Repository: CleasbyCode/pdvzip Branch: main Commit: 352c741e6290 Files: 21 Total size: 548.5 KB Directory structure: gitextract_u94dvs2j/ ├── LICENSE ├── README.md └── src/ ├── archive_analysis.cpp ├── binary_utils.cpp ├── compile_pdvzip.sh ├── display_info.cpp ├── file_io.cpp ├── image_processing.cpp ├── image_processing_internal.h ├── image_resize.cpp ├── lodepng/ │ ├── LICENSE │ ├── lodepng.cpp │ └── lodepng.h ├── main.cpp ├── pdvzip.h ├── polyglot_assembly.cpp ├── program_args.cpp ├── script_builder.cpp ├── script_builder_internal.h ├── script_text_builder.cpp └── user_input.cpp ================================================ FILE CONTENTS ================================================ ================================================ FILE: LICENSE ================================================ MIT License Copyright (c) 2022-2026 Nicholas Cleasby Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ================================================ FILE: README.md ================================================ # pdvzip Embed a ***ZIP*** or ***JAR*** file within a ***PNG*** image to create a ***tweetable*** and "[***executable***](https://github.com/CleasbyCode/pdvzip#extracting-your-embedded-files)" ***PNG*** polyglot file. Share the image on ***X-Twitter*** and a few other compatible platforms, which retains the embedded archive. *Note: For compatibility reasons, please ***do not*** use encrypted / password protected ZIP files.* There is also a [***Web edition***](https://cleasbycode.co.uk/pdvzip/app/), which you can use immediately, as a convenient alternative to downloading and compiling the CLI source code. Web file uploads are limited to **20MB**. Based on the similar idea by [***David Buchanan***](https://www.da.vidbuchanan.co.uk/), from his original ***Python*** program [***tweetable-polyglot-png***](https://github.com/DavidBuchanan314/tweetable-polyglot-png), ***pdvzip*** uses different methods for [***storing***](https://github.com/CleasbyCode/pdvzip#png-image-requirements-for-arbitrary-data-preservation) and [***extracting***](https://github.com/CleasbyCode/pdvzip#extracting-your-embedded-files) embedded files within a ***PNG*** image. ![Demo Image](https://github.com/CleasbyCode/pdvzip/blob/main/demo_image/HDO2mHoWYAAUxIy.png) ***Credits:*** *Image* - [***@KCP228***](https://x.com/KCP228) *PowerShell Script* - [***@gierrofo***](https://x.com/gierrofo) The ***Linux/Windows*** extraction script is stored within the ***iCCP*** chunk of the ***PNG*** image. The embedded ***ZIP/JAR*** file is stored within its own ***IDAT*** chunk, which will be the last ***IDAT*** chunk of the image file. With ***pdvzip***, you can embed a ***ZIP/JAR*** file up to a maximum size of ***2GB** (cover image + archive file). Compatible sites, ***listed below***, have their own ***much smaller*** size limits. ## Compatible Platforms *Posting size limit measured by the combined size of the cover image + compressed data file.* * ***X-Twitter*** (**5MB**), ***Flickr*** (**200MB**), ***ImgBB*** (**32MB**), ***PostImage*** (**32MB**), ***ImgPile*** (**8MB**). *Image dimension size limits:* * ***PNG-32/24*** (*Truecolor*) **68x68** Min. - **900x900** Max. * ***PNG-8*** (*Indexed-color*) **68x68** Min. - **4096x4096** Max. ## Usage (Linux) ```console $ chmod +x compile_pdvzip.sh $ ./compile_pdvzip.sh Compiling pdvzip... Compilation successful. Executable 'pdvzip' created. $ sudo cp pdvzip /usr/bin $ pdvzip Usage: pdvzip pdvzip --info $ pdvzip my_cover_image.png document_pdf.zip Created PNG-ZIP polyglot image file: pzip_55183.png (4038367 bytes). Complete! $ pdvzip my_cover_image.png hello_world.jar Created PNG-JAR polyglot image file: pjar_19662.png (1016336 bytes). Complete! ``` ## Extracting Your Embedded File(s) **Important:** When saving images from ***X-Twitter***, click the image in the post to ***fully expand it***, before saving. The following section covers the extraction of embedded ***ZIP*** files. ***JAR*** files are covered later. ***pdvzip*** (for ***Linux***) will attempt to ***automatically set executable permissions*** on newly created polyglot image files. You will need to manually set executable permissions using ***chmod*** on these polyglot images downloaded from hosting sites or copied from another machine. https://github.com/user-attachments/assets/8feca575-b135-4f58-839a-2159fce09b44 https://github.com/user-attachments/assets/77472a02-52dd-4a5c-a035-b30dcc842cce https://github.com/user-attachments/assets/a143e694-31f5-4235-ace1-30217fe8ab41 ***Linux - using bash (or sh) shell environment.*** ```console $ ./pzip_55183.png ``` **For any other Linux shell environment, you will probably need to invoke bash (or sh) to run the image file.** ```console mx% bash ./pzip_55183.png ``` Alternative extraction (***Linux***). Using ***wget*** to download and run the image directly from the hosting site. ***X-Twitter*** ***wget*** example: **Image with embedded ***python*** script**. ```console $ wget -O Fibo.png "https://pbs.twimg.com/media/GLXTYeCWMAAA6B_.png";chmod +x Fibo.png;bash ./Fibo.png ``` **Windows** ***(Rename the image file extension to '.cmd')*** ```console G:\demo> ren pzip_55183.png pzip_55183.cmd G:\demo> .\pzip_55183.cmd ``` Alternative extraction (***Windows***). Using ***iwr*** to download and run the image directly from the hosting site. ***Flickr*** ***iwr*** example: **Image with embedded mp4 video file.** ```console iwr -o swing.cmd "https://live.staticflickr.com/65535/54025688614_2f9d474cba_o_d.png";.\swing.cmd ``` Opening the ***.cmd*** file from the desktop, on its first run, ***Windows*** may display a security warning. Clear this by clicking '***More info***' then select '***Run anyway***'. To avoid security warnings, run the file from a ***Windows console***, as shown in the above example. ***The file (or folder) within the ZIP archive that appears first within the ZIP file record, determines what extraction script, based on file type, is used.*** For common ***video & audio*** files, ***Linux*** will first attempt to use the media player ***mpv*** or ***vlc*** if no ***mpv***. ***Firefox*** is used as a last resort. ***Windows*** uses the default media player. ***PDF*** - ***Linux*** will use ***evince*** or ***firefox***. ***Windows*** uses the default ***PDF*** viewer. ***Python*** - ***Linux*** & ***Windows*** use ***python3*** to run these programs. ***PowerShell*** - ***Linux*** uses ***pwsh*** (if installed), ***Windows*** uses either ***powershell.exe*** or ***pwsh.exe*** to run these scripts. ***Folder*** - ***Linux*** uses ***xdg-open***, ***Windows*** uses ***powershell.exe*** with II (***Invoke-Item***) command, to open zipped folders. For any other file type within your ***ZIP*** file, ***Linux*** & ***Windows*** will rely on the operating system's set default method/application. Obviously, the compressed/embedded file needs to be compatible with the operating system you run it on. If the archive file is ***JAR*** or the compressed file type within the ***ZIP*** archive is ***PowerShell***, ***Python***, ***Shell Script*** or a ***Windows/Linux Executable, pdvzip*** will give you the option to provide command-line arguments for your file, if required. The ***command-line arguments*** will be added to the ***Linux/Windows*** extraction script, embedded within the ***iCCP*** chunk of your ***PNG*** cover image. Make sure to enclose arguments containing spaces, such as file & directory names, within "quotation" marks. e.g. ```console $ ./pdvzip my_cover_image.png jdvrif_linux_executable.zip For this file type you can provide command-line arguments here, if required. Linux: -e ../my_cover_image.jpg "../my document file.pdf" ``` Also, be aware when using arguments for the compressed ***ZIP*** file types (not ***JAR***), that you are always working from within a created subdirectory "***pdvzip_xxxx (e.g. pdvzip_5444)***". https://github.com/user-attachments/assets/e55e9671-423c-4439-89e6-356c0080b4c1 https://github.com/user-attachments/assets/8d6d97c1-4c70-4f60-bba5-b01fad08b60e To just get access to the file(s) within the ***ZIP*** archive, rename the '***.png***' file extension to '***.zip***'. Treat the ***ZIP*** archive as read-only, do not add or remove files from the ***PNG-ZIP*** polyglot file. ## Executing Embedded Java Programs ***Linux Option 1:*** ```console $ java -jar pjar_19662.png Note: If you use this method to run your embedded Java program, you will have to manually add command-line arguments (if required) to the end of the command, as your embedded arguments will not work with this method. e.g. user1@mx:~/Desktop$ java -jar ./pjar_19662.png -u john_s -a 42 -f "John Smith" ``` ***Linux Option 2a, using bash (or sh) shell environment:*** ```console $ ./pjar_19662.png Note: This method will execute the embedded Java program and also use any embedded command-line arguments with the Java program. ``` ***Linux Option 2b, using any other shell environment, you will need to invoke bash (or sh) to execute the image:*** ```console mx% bash ./pjar_19662.png ``` ***Windows Option 1:*** ```console PS C:\Users\Nick\Desktop\jar_demo> java -jar .\pjar_19662.png Note: If you use this method to run your embedded Java program, you will have to manually add command-line arguments (if required) to the end of the command, as your embedded arguments will not work with this method. e.g. PS C:\Users\Nick\Desktop\jar_demo> java -jar .\pjar_19662.png -u john_s -a 42 -f "John Smith" ``` ***Windows Option 2:*** ```console PS C:\Users\Nick\Desktop\jar_demo> ren .\pjar_19662.png .\pjar_19662.cmd PS C:\Users\Nick\Desktop\jar_demo> .\pjar_19662.cmd Note: This method will execute the embedded Java program and will also use any embedded command-line arguments with the Java program. ``` https://github.com/user-attachments/assets/9451ad50-4c7c-4fa3-a1be-3854189bde00 ## PNG Image Requirements for Arbitrary Data Preservation ***PNG*** file size (image + archive file) must not exceed the platform's size limit. The site will either refuse to upload your image or it will convert your image to ***jpg***, such as ***X-Twitter***, and you will lose the embedded content. ***Dimensions:*** ***PNG-32/24 (Truecolor)*** Image dimensions can be set between a minimum of **68 x 68** and a maximum of **900 x 900**. ***Note:*** *A cover image that is detected as ***PNG-32/24 Truecolor (color type 6 or 2),*** with less than 257 colors, will be converted by ***pdvzip*** to a ***PNG-8 Indexed-color (color type 3)*** image. This is done for compatiblity reasons as it should prevent platforms such as ***X-Twitter*** from also converting your image, which would result in the loss of the embedded archive file.* ***PNG-8 (Indexed-color)*** Image dimensions can be set between a minimum of **68 x 68** and a maximum of **4096 x 4096**. ***PNG Chunks:*** For example, with ***X-Twitter*** you can ***overfill*** the following ***PNG*** chunks with arbitrary data, in which the platform will preserve as long as you keep within the image dimension & file size limits. ***bKGD, cHRM, gAMA, hIST,*** *iCCP (Limited size chunk. 10KB Max. with X-Twitter)*, ***IDAT (Use as last IDAT chunk, after the final image IDAT chunk), PLTE (Use only with ***PNG-32/24*** images), pHYs, sBIT, sPLT, sRGB,*** *tRNS (Use only with PNG-32 images).* *Other platforms may differ in what chunks they preserve and which ones you can overfill.* ***pdvzip*** uses the chunks ***iCCP*** (stores extraction script) and ***IDAT*** (stores the ***ZIP/JAR*** file) for your arbitrary data. ## ***ZIP/JAR*** File Size & Other Important Information To work out the maximum ***ZIP/JAR*** file size, start with the size limit, minus the image size, minus ***1500*** bytes (extraction script size). ***X-Twitter*** example: (**5MB** limit) **5,242,880** - (**307,200** [image] + **1500** [extraction script]) = **4,934,180 bytes** available for your ***ZIP/JAR*** file. * Make sure your ***ZIP/JAR*** file is a standard ***ZIP/JAR*** archive, compatible with ***Linux*** unzip & ***Windows*** Explorer. * Do not include more than one ***.zip*** file within the main ***ZIP*** archive. (***.rar*** files are ok). * Do not include other ***pdvzip*** created ***PNG*** image files within the main ***ZIP*** archive, as they are essentially ***.zip*** files. * Always use file extensions for your file(s) within the ***ZIP*** archive: ***my_doc.pdf***, ***my_video.mp4***, ***my_program.py***, etc. A file without an extension within a ***ZIP*** archive will be considered a ***Linux*** executable. ## An 8 File Tweetable PNG Polyglot ![Polyglot Image](https://github.com/CleasbyCode/pdvzip/blob/main/demo_image/Png_P0wershell_Z1p.png) https://github.com/user-attachments/assets/d1b5888c-fe91-4a58-8ad6-731d9165a57c A while ago I put together an 8 file (tweetable) PNG polyglot file. I recently found it again, so thought I would share it here. I have made some changes to the polyglot, such as improving the PowerShell script and using a different MP4 video file that is embedded within the image (this is extracted and played by the PowerShell script). The PNG polyglot file consists of the image itself - PNG, a Web page, ZIP archive, MP3 audio file, JAR (executable Java program), RAR archive, PDF and a PS1 (PowerShell) script. To open and view the PDF document within the PNG image, just change the file extension to .pdf, under Windows you should be able to view the PDF using most Web browsers, such as Brave, Chrome & Firefox. It is the same with Linux, including most Linux PDF viewers. To play the audio file, change the extension to .mp3, and open the file under Windows with the VLC media player or the Windows legacy media player. With Linux, use the VLC media player. To run the Java program, change the extension to .jar. From the Desktop in both Windows and Linux, you should be able to just double-click the icon to run. It should open and display the Calculator app on your Desktop. To access the ZIP archive with Windows, change the extension to .zip and open it with Windows Explorer. You can also use the Expand-Archive command from a Windows terminal. With Linux use the CLI tool ***unzip***. To access the RAR archive with Windows, change the extension to .rar and use the WinRAR application. With Linux use the ***unrar*** CLI tool (e.g. $ unrar e image_file.rar). To view the embedded Web page, just change the file extension to .htm, open and view it with any browser. To run the embedded PowerShell script on Windows, change the file extension to .ps1 and from the terminal run the following command: ```console PS C:\Users\Nick\Desktop> powershell -ExecutionPolicy Bypass -File .\image_file.ps1 ``` To run the PowerShell script on Linux, first make sure you have PowerShell installed as it is not installed by default. Again, change the file extension to .ps1. From the Linux terminal, run the following command: ```console $ pwsh ./image_file.ps1 ``` The PowerShell script will extract and play an MP4 video file embedded within the image. Video credit: The video file used in the PowerShell example is the work of [***@doopiidoop***](https://x.com/doopiidoop) ## Third-Party Libraries This project includes the following third-party library: - **LodePNG** by Lode Vandevenne - License: zlib/libpng (see [***LICENSE***](https://github.com/lvandeve/lodepng/blob/master/LICENSE) file) - Copyright (c) 2005-2024 Lode Vandevenne ## ================================================ FILE: src/archive_analysis.cpp ================================================ #include "pdvzip.h" namespace { template [[nodiscard]] T readZipField(std::span data, std::size_t offset, std::string_view context) { static_assert(sizeof(T) == 2 || sizeof(T) == 4); try { if constexpr (sizeof(T) == 2) { return static_cast(readLe16(data, offset)); } else { return static_cast(readLe32(data, offset)); } } catch (const std::exception&) { throw std::runtime_error(std::format("{}: Truncated ZIP record.", context)); } } [[nodiscard]] bool containsControlCharacters(std::string_view value) { return std::ranges::any_of(value, [](unsigned char c) { return std::iscntrl(c) != 0; }); } [[nodiscard]] char toLowerAscii(char ch) { if (ch >= 'A' && ch <= 'Z') { return static_cast(ch - 'A' + 'a'); } return ch; } [[nodiscard]] std::string_view readZipStringView(std::span data, std::size_t start, std::size_t length, std::string_view overflow_error, std::string_view bounds_error) { const std::size_t end = checkedAdd(start, length, overflow_error); if (end > data.size()) { throw std::runtime_error(std::string(bounds_error)); } return std::string_view(reinterpret_cast(data.data() + start), length); } [[nodiscard]] bool hasWindowsReservedSegmentName(std::string_view segment) { const std::size_t dot_pos = segment.find('.'); const std::string_view stem = segment.substr(0, dot_pos); auto equalsReservedName = [](std::string_view lhs, std::string_view rhs) { return std::ranges::equal(lhs, rhs, [](char a, char b) { return toLowerAscii(a) == b; }); }; if (equalsReservedName(stem, "con"sv) || equalsReservedName(stem, "prn"sv) || equalsReservedName(stem, "aux"sv) || equalsReservedName(stem, "nul"sv)) { return true; } return stem.size() == 4 && stem[3] >= '1' && stem[3] <= '9' && ((toLowerAscii(stem[0]) == 'c' && toLowerAscii(stem[1]) == 'o' && toLowerAscii(stem[2]) == 'm') || (toLowerAscii(stem[0]) == 'l' && toLowerAscii(stem[1]) == 'p' && toLowerAscii(stem[2]) == 't')); } [[nodiscard]] bool hasWindowsInvalidPathCharacter(std::string_view segment) { return std::ranges::any_of(segment, [](char ch) { return ch == '<' || ch == '>' || ch == ':' || ch == '"' || ch == '|' || ch == '?' || ch == '*'; }); } [[nodiscard]] std::string makePortableEntryKey(std::string_view path) { std::string key; key.reserve(path.size()); for (char ch : path) { key.push_back(ch == '\\' ? '/' : toLowerAscii(ch)); } while (!key.empty() && key.back() == '/') { key.pop_back(); } return key; } [[nodiscard]] bool isUnsafeEntryPath(std::string_view path); struct LocalEntrySpan { std::size_t begin; std::size_t end; }; constexpr std::size_t ZIP_WRAP_PREFIX_SIZE = 8, ZIP_WRAP_TRAILER_SIZE = 4, LOCAL_RECORD_MIN_SIZE = 30, LOCAL_RECORD_NAME_INDEX = 30, CENTRAL_RECORD_MIN_SIZE = 46, CENTRAL_RECORD_NAME_INDEX = 46, CENTRAL_VERSION_MADE_BY = 4, CENTRAL_FLAGS_OFFSET = 8, CENTRAL_CRC32 = 16, CENTRAL_COMPRESSED_SIZE = 20, CENTRAL_UNCOMPRESSED_SIZE = 24, CENTRAL_NAME_LENGTH_OFFSET = 28, CENTRAL_EXTRA_LENGTH_OFFSET = 30, CENTRAL_COMMENT_LENGTH_OFFSET = 32, CENTRAL_DISK_START = 34, CENTRAL_EXTERNAL_ATTRIBUTES = 38, CENTRAL_LOCAL_OFFSET = 42; struct CentralDirectoryBounds { std::size_t start; std::size_t end; uint16_t total_records; }; struct CentralEntryMetadata { std::size_t entry_number; uint16_t version_made_by; uint16_t flags; uint32_t crc32; uint32_t compressed_size; uint32_t uncompressed_size; uint16_t disk_start; uint32_t external_attributes; std::size_t local_header_offset; std::string_view name; std::size_t record_size; }; struct ArchiveEntryTracking { std::uint64_t total_uncompressed = 0; std::unordered_set seen_entries; std::unordered_set file_entries; std::unordered_set directory_entries; std::vector local_spans; void reserve(std::size_t total_records) { seen_entries.reserve(total_records); file_entries.reserve(total_records); directory_entries.reserve(total_records); local_spans.reserve(total_records); } }; void validateEntryName(std::string_view entry_name, std::string_view control_label, std::string_view unsafe_error, std::optional entry_number = std::nullopt) { if (containsControlCharacters(entry_name)) { throw std::runtime_error(entry_number ? std::format("{} {} contains unsupported control characters.", control_label, *entry_number) : std::string(control_label)); } if (isUnsafeEntryPath(entry_name)) { throw std::runtime_error(std::format("{}: \"{}\".", unsafe_error, entry_name)); } } [[nodiscard]] bool isUnixLikeZipHost(uint16_t version_made_by) { const Byte host = static_cast(version_made_by >> 8); return host == 3 // UNIX || host == 19; // macOS/OS X } void validateEntryAttributes(uint16_t version_made_by, uint16_t flags, uint32_t external_attributes, std::string_view entry_name, std::size_t entry_number) { constexpr uint16_t GENERAL_PURPOSE_ENCRYPTED = 1u << 0, GENERAL_PURPOSE_STRONG_ENCRYPTION = 1u << 6; constexpr uint32_t UNIX_FILE_TYPE_MASK = 0170000, UNIX_REGULAR_FILE = 0100000, UNIX_DIRECTORY = 0040000, UNIX_SYMLINK = 0120000; if ((flags & (GENERAL_PURPOSE_ENCRYPTED | GENERAL_PURPOSE_STRONG_ENCRYPTION)) != 0) { throw std::runtime_error(std::format( "Archive Security Error: Encrypted archive entry {} is not supported.", entry_number)); } if (!isUnixLikeZipHost(version_made_by)) { return; } const uint32_t mode_type = (external_attributes >> 16) & UNIX_FILE_TYPE_MASK; if (mode_type == 0) { return; } if (mode_type == UNIX_SYMLINK) { throw std::runtime_error(std::format( "Archive Security Error: Symlink archive entry {} is not supported: \"{}\".", entry_number, entry_name)); } if (mode_type != UNIX_REGULAR_FILE && mode_type != UNIX_DIRECTORY) { throw std::runtime_error(std::format( "Archive Security Error: Special archive entry {} is not supported: \"{}\".", entry_number, entry_name)); } if (mode_type == UNIX_DIRECTORY && !entry_name.ends_with('/')) { throw std::runtime_error(std::format( "Archive File Error: Directory metadata does not match archive entry path {}.", entry_number)); } if (mode_type == UNIX_REGULAR_FILE && entry_name.ends_with('/')) { throw std::runtime_error(std::format( "Archive File Error: File metadata does not match archive entry path {}.", entry_number)); } } void validateEntrySizeMetadata(uint32_t compressed_size, uint32_t uncompressed_size, std::uint64_t& total_uncompressed, bool is_directory, std::size_t entry_number) { constexpr std::uint64_t MAX_TOTAL_UNCOMPRESSED_SIZE = 2ULL * 1024 * 1024 * 1024; if (compressed_size == UINT32_MAX || uncompressed_size == UINT32_MAX) { throw std::runtime_error(std::format( "Archive File Error: ZIP64 size metadata is not supported for entry {}.", entry_number)); } if (is_directory) { // A directory entry must have no actual content (uncompressed_size == 0). // compressed_size may legitimately be non-zero — Java's jar tool deflates // directory entries, producing a 2-byte empty-stream marker (0x03 0x00). if (uncompressed_size != 0) { throw std::runtime_error(std::format( "Archive File Error: Directory entry {} has non-zero uncompressed size.", entry_number)); } return; } if (static_cast(uncompressed_size) > MAX_TOTAL_UNCOMPRESSED_SIZE || total_uncompressed > MAX_TOTAL_UNCOMPRESSED_SIZE - static_cast(uncompressed_size)) { throw std::runtime_error("Archive Security Error: Total uncompressed archive size exceeds the safety limit."); } total_uncompressed += uncompressed_size; } void validateEntryPathCollision(std::string_view entry_name, std::unordered_set& seen_entries, std::unordered_set& file_entries, std::unordered_set& directory_entries, std::size_t entry_number) { const bool is_directory = entry_name.ends_with('/'); const std::string key = makePortableEntryKey(entry_name); if (key.empty()) { throw std::runtime_error(std::format( "Archive Security Error: Empty normalized path for archive entry {}.", entry_number)); } if (!seen_entries.insert(key).second) { throw std::runtime_error(std::format( "Archive Security Error: Duplicate or case-conflicting archive entry path detected: \"{}\".", entry_name)); } std::string parent; parent.reserve(key.size()); for (char ch : key) { if (ch == '/') { if (file_entries.contains(parent)) { throw std::runtime_error(std::format( "Archive Security Error: Archive entry {} conflicts with file path \"{}\".", entry_number, parent)); } directory_entries.insert(parent); } parent.push_back(ch); } if (is_directory) { if (file_entries.contains(key)) { throw std::runtime_error(std::format( "Archive Security Error: Directory entry {} conflicts with an existing file path.", entry_number)); } directory_entries.insert(key); return; } if (directory_entries.contains(key)) { throw std::runtime_error(std::format( "Archive Security Error: File entry {} conflicts with an existing directory path.", entry_number)); } file_entries.insert(key); } [[nodiscard]] bool descriptor32Matches(std::span archive_data, std::size_t offset, uint32_t crc32, uint32_t compressed_size, uint32_t uncompressed_size) { return readLe32(archive_data, offset) == crc32 && readLe32(archive_data, offset + 4) == compressed_size && readLe32(archive_data, offset + 8) == uncompressed_size; } [[nodiscard]] std::size_t readDataDescriptorLength(std::span archive_data, std::size_t descriptor_start, std::size_t central_start, uint32_t crc32, uint32_t compressed_size, uint32_t uncompressed_size, std::size_t entry_number) { constexpr std::size_t DESCRIPTOR_WITHOUT_SIGNATURE_SIZE = 12, DESCRIPTOR_WITH_SIGNATURE_SIZE = 16; if (descriptor_start > central_start) { throw std::runtime_error(std::format( "Archive File Error: Compressed data for entry {} extends past the central directory.", entry_number)); } const std::size_t available = central_start - descriptor_start; if (available >= DESCRIPTOR_WITH_SIGNATURE_SIZE && hasLe32Signature(archive_data, descriptor_start, ZIP_DATA_DESCRIPTOR_SIGNATURE) && descriptor32Matches(archive_data, descriptor_start + 4, crc32, compressed_size, uncompressed_size)) { return DESCRIPTOR_WITH_SIGNATURE_SIZE; } if (available >= DESCRIPTOR_WITHOUT_SIGNATURE_SIZE && descriptor32Matches(archive_data, descriptor_start, crc32, compressed_size, uncompressed_size)) { return DESCRIPTOR_WITHOUT_SIGNATURE_SIZE; } throw std::runtime_error(std::format( "Archive File Error: Data descriptor for entry {} is missing or inconsistent.", entry_number)); } void validateLocalEntryPayload(std::span archive_data, std::size_t local_header_start, std::size_t local_record_end, std::size_t central_start, uint16_t central_flags, uint32_t crc32, uint32_t compressed_size, uint32_t uncompressed_size, std::vector& local_spans, std::size_t entry_number) { constexpr uint16_t GENERAL_PURPOSE_ENCRYPTED = 1u << 0, GENERAL_PURPOSE_DATA_DESCRIPTOR = 1u << 3, GENERAL_PURPOSE_STRONG_ENCRYPTION = 1u << 6; constexpr uint16_t FLAGS_THAT_AFFECT_LAYOUT = GENERAL_PURPOSE_ENCRYPTED | GENERAL_PURPOSE_DATA_DESCRIPTOR | GENERAL_PURPOSE_STRONG_ENCRYPTION; const uint16_t local_flags = readZipField(archive_data, local_header_start + 6, "Archive File Error"); if ((local_flags & FLAGS_THAT_AFFECT_LAYOUT) != (central_flags & FLAGS_THAT_AFFECT_LAYOUT)) { throw std::runtime_error(std::format( "Archive File Error: Local and central ZIP flags differ for entry {}.", entry_number)); } const bool has_data_descriptor = (central_flags & GENERAL_PURPOSE_DATA_DESCRIPTOR) != 0; if (!has_data_descriptor) { const uint32_t local_crc32 = readZipField(archive_data, local_header_start + 14, "Archive File Error"); const uint32_t local_compressed_size = readZipField(archive_data, local_header_start + 18, "Archive File Error"); const uint32_t local_uncompressed_size = readZipField(archive_data, local_header_start + 22, "Archive File Error"); if (local_crc32 != crc32 || local_compressed_size != compressed_size || local_uncompressed_size != uncompressed_size) { throw std::runtime_error(std::format( "Archive File Error: Local and central size metadata differ for entry {}.", entry_number)); } } const std::size_t compressed_end = checkedAdd( local_record_end, static_cast(compressed_size), "Archive File Error: Local compressed data size overflow."); if (compressed_end > central_start) { throw std::runtime_error(std::format( "Archive File Error: Compressed data for entry {} extends into the central directory.", entry_number)); } std::size_t local_payload_end = compressed_end; if (has_data_descriptor) { local_payload_end = checkedAdd( compressed_end, readDataDescriptorLength( archive_data, compressed_end, central_start, crc32, compressed_size, uncompressed_size, entry_number), "Archive File Error: Local data descriptor size overflow."); if (local_payload_end > central_start) { throw std::runtime_error(std::format( "Archive File Error: Data descriptor for entry {} extends into the central directory.", entry_number)); } } local_spans.push_back(LocalEntrySpan{ .begin = local_header_start, .end = local_payload_end }); } void validateLocalEntrySpans(std::vector& local_spans) { std::ranges::sort(local_spans, [](const LocalEntrySpan& lhs, const LocalEntrySpan& rhs) { return lhs.begin < rhs.begin; }); for (std::size_t i = 1; i < local_spans.size(); ++i) { if (local_spans[i].begin < local_spans[i - 1].end) { throw std::runtime_error("Archive File Error: Local ZIP entry payloads overlap."); } } } [[nodiscard]] std::size_t centralRecordSize(std::size_t name_length, std::size_t extra_length, std::size_t comment_length) { return checkedAdd( CENTRAL_RECORD_MIN_SIZE, checkedAdd( name_length, checkedAdd( extra_length, comment_length, "Archive File Error: Central directory metadata length overflow."), "Archive File Error: Central directory metadata length overflow."), "Archive File Error: Central directory record size overflow."); } [[nodiscard]] CentralDirectoryBounds readCentralDirectoryBounds(std::span archive_data, std::size_t eocd_index) { const uint16_t disk_number = readZipField(archive_data, eocd_index + 4, "Archive File Error"); const uint16_t central_dir_disk = readZipField(archive_data, eocd_index + 6, "Archive File Error"); const uint16_t records_on_disk = readZipField(archive_data, eocd_index + 8, "Archive File Error"); const uint16_t total_records = readZipField(archive_data, eocd_index + 10, "Archive File Error"); const uint32_t central_size = readZipField(archive_data, eocd_index + 12, "Archive File Error"); const uint32_t central_offset = readZipField(archive_data, eocd_index + 16, "Archive File Error"); if (disk_number != 0 || central_dir_disk != 0 || records_on_disk != total_records) { throw std::runtime_error("Archive File Error: Multi-disk ZIP archives are not supported."); } if (total_records == 0) { throw std::runtime_error("Archive File Error: Archive contains no central directory entries."); } if (total_records == UINT16_MAX || central_size == UINT32_MAX || central_offset == UINT32_MAX) { throw std::runtime_error("Archive File Error: ZIP64 archives are not supported."); } const std::size_t central_start = checkedAdd( ZIP_WRAP_PREFIX_SIZE, static_cast(central_offset), "Archive File Error: Central directory offset overflow."); const std::size_t central_end = checkedAdd( central_start, static_cast(central_size), "Archive File Error: Central directory size overflow."); if (central_start > archive_data.size() || central_end > archive_data.size() || central_end > eocd_index) { throw std::runtime_error("Archive File Error: Central directory bounds are invalid."); } if (central_end != eocd_index) { throw std::runtime_error("Archive File Error: Central directory does not end at the EOCD record."); } return CentralDirectoryBounds{ .start = central_start, .end = central_end, .total_records = total_records }; } [[nodiscard]] CentralEntryMetadata readCentralEntryMetadata(std::span archive_data, std::size_t cursor, std::size_t entry_number) { if (cursor > archive_data.size() || CENTRAL_RECORD_MIN_SIZE > archive_data.size() - cursor) { throw std::runtime_error("Archive File Error: Truncated central directory file header."); } if (!hasLe32Signature(archive_data, cursor, ZIP_CENTRAL_DIRECTORY_SIGNATURE)) { throw std::runtime_error("Archive File Error: Invalid central directory file header signature."); } const uint16_t version_made_by = readZipField(archive_data, cursor + CENTRAL_VERSION_MADE_BY, "Archive File Error"); const uint16_t flags = readZipField(archive_data, cursor + CENTRAL_FLAGS_OFFSET, "Archive File Error"); const uint32_t crc32 = readZipField(archive_data, cursor + CENTRAL_CRC32, "Archive File Error"); const uint32_t compressed_size = readZipField(archive_data, cursor + CENTRAL_COMPRESSED_SIZE, "Archive File Error"); const uint32_t uncompressed_size = readZipField(archive_data, cursor + CENTRAL_UNCOMPRESSED_SIZE, "Archive File Error"); const std::size_t name_length = readZipField(archive_data, cursor + CENTRAL_NAME_LENGTH_OFFSET, "Archive File Error"); const std::size_t extra_length = readZipField(archive_data, cursor + CENTRAL_EXTRA_LENGTH_OFFSET, "Archive File Error"); const std::size_t comment_length = readZipField(archive_data, cursor + CENTRAL_COMMENT_LENGTH_OFFSET, "Archive File Error"); const uint16_t disk_start = readZipField(archive_data, cursor + CENTRAL_DISK_START, "Archive File Error"); const uint32_t external_attributes = readZipField(archive_data, cursor + CENTRAL_EXTERNAL_ATTRIBUTES, "Archive File Error"); const std::size_t local_header_offset = readZipField(archive_data, cursor + CENTRAL_LOCAL_OFFSET, "Archive File Error"); const std::size_t name_start = checkedAdd( cursor, CENTRAL_RECORD_NAME_INDEX, "Archive File Error: Central directory filename offset overflow."); const std::string_view name = readZipStringView( archive_data, name_start, name_length, "Archive File Error: Central directory filename length overflow.", "Archive File Error: Central directory filename exceeds archive bounds."); const std::size_t record_size = centralRecordSize(name_length, extra_length, comment_length); return CentralEntryMetadata{ .entry_number = entry_number, .version_made_by = version_made_by, .flags = flags, .crc32 = crc32, .compressed_size = compressed_size, .uncompressed_size = uncompressed_size, .disk_start = disk_start, .external_attributes = external_attributes, .local_header_offset = local_header_offset, .name = name, .record_size = record_size }; } void validateCentralRecordSpan(std::size_t cursor, std::size_t record_size, std::size_t central_end, std::size_t archive_size) { if (record_size > archive_size - cursor) { throw std::runtime_error("Archive File Error: Central directory entry exceeds archive bounds."); } if (cursor > central_end || record_size > central_end - cursor) { throw std::runtime_error("Archive File Error: Central directory entry exceeds declared directory size."); } } void validateCentralEntryMetadata(const CentralEntryMetadata& entry, ArchiveEntryTracking& tracking) { if (entry.disk_start != 0) { throw std::runtime_error(std::format( "Archive File Error: Multi-disk local header reference on entry {} is not supported.", entry.entry_number)); } validateEntryName( entry.name, "Archive File Error: Entry", "Archive Security Error: Unsafe archive entry path detected", entry.entry_number); validateEntryAttributes( entry.version_made_by, entry.flags, entry.external_attributes, entry.name, entry.entry_number); validateEntrySizeMetadata( entry.compressed_size, entry.uncompressed_size, tracking.total_uncompressed, entry.name.ends_with('/'), entry.entry_number); validateEntryPathCollision( entry.name, tracking.seen_entries, tracking.file_entries, tracking.directory_entries, entry.entry_number); } void validateLocalEntryForCentralEntry(std::span archive_data, std::size_t central_start, const CentralEntryMetadata& entry, std::vector& local_spans) { const std::size_t local_header_start = checkedAdd( ZIP_WRAP_PREFIX_SIZE, entry.local_header_offset, "Archive File Error: Local file header offset overflow."); if (local_header_start >= central_start) { throw std::runtime_error("Archive File Error: Local file header points inside the central directory."); } if (local_header_start > archive_data.size() || LOCAL_RECORD_MIN_SIZE > archive_data.size() - local_header_start) { throw std::runtime_error("Archive File Error: Truncated local file header."); } if (!hasLe32Signature(archive_data, local_header_start, ZIP_LOCAL_FILE_HEADER_SIGNATURE)) { throw std::runtime_error(std::format( "Archive File Error: Invalid local file header signature for entry {}.", entry.entry_number)); } const std::size_t local_name_length = readZipField(archive_data, local_header_start + 26, "Archive File Error"); const std::size_t local_extra_length = readZipField(archive_data, local_header_start + 28, "Archive File Error"); const std::size_t local_name_start = checkedAdd( local_header_start, LOCAL_RECORD_NAME_INDEX, "Archive File Error: Local filename offset overflow."); const std::size_t local_record_end = checkedAdd( checkedAdd( local_name_start, local_name_length, "Archive File Error: Local filename length overflow."), local_extra_length, "Archive File Error: Local header extra-field length overflow."); if (local_record_end > archive_data.size()) { throw std::runtime_error("Archive File Error: Local file header exceeds archive bounds."); } const std::string_view local_entry_name = readZipStringView( archive_data, local_name_start, local_name_length, "Archive File Error: Local filename length overflow.", "Archive File Error: Local file header exceeds archive bounds."); validateEntryName( local_entry_name, "Archive File Error: Local entry", "Archive Security Error: Unsafe local archive entry path detected", entry.entry_number); if (local_entry_name != entry.name) { throw std::runtime_error(std::format( "Archive Security Error: Local and central directory names differ for entry {}.", entry.entry_number)); } validateLocalEntryPayload( archive_data, local_header_start, local_record_end, central_start, entry.flags, entry.crc32, entry.compressed_size, entry.uncompressed_size, local_spans, entry.entry_number); } [[nodiscard]] std::string parseFirstZipFilename(std::span archive_data) { constexpr std::size_t ZIP_LOCAL_HEADER_INDEX = 8, ZIP_LOCAL_HEADER_MIN_SIZE = 30, FILENAME_LENGTH_INDEX = ZIP_LOCAL_HEADER_INDEX + 26, EXTRA_LENGTH_INDEX = ZIP_LOCAL_HEADER_INDEX + 28, FILENAME_INDEX = ZIP_LOCAL_HEADER_INDEX + 30, FIRST_FILENAME_MIN_LENGTH = 4; if (archive_data.size() < ZIP_LOCAL_HEADER_INDEX + ZIP_LOCAL_HEADER_MIN_SIZE) { throw std::runtime_error("Archive File Error: ZIP header is truncated."); } if (!hasLe32Signature(archive_data, ZIP_LOCAL_HEADER_INDEX, ZIP_LOCAL_FILE_HEADER_SIGNATURE)) { throw std::runtime_error("Archive File Error: Missing ZIP local file header signature."); } const std::size_t filename_length = readZipField(archive_data, FILENAME_LENGTH_INDEX, "Archive File Error"); const std::size_t extra_length = readZipField(archive_data, EXTRA_LENGTH_INDEX, "Archive File Error"); if (filename_length < FIRST_FILENAME_MIN_LENGTH) { throw std::runtime_error( "File Error:\n\nName length of first file within archive is too short.\n" "Increase length (minimum 4 characters). Make sure it has a valid extension."); } const std::string filename(readZipStringView( archive_data, FILENAME_INDEX, filename_length, "Archive File Error: First filename length overflow.", "Archive File Error: First filename extends past archive bounds.")); // Extra field bounds validation helps catch malformed local headers early. if (checkedAdd( FILENAME_INDEX + filename_length, extra_length, "Archive File Error: First ZIP header extra field length overflow.") > archive_data.size()) { throw std::runtime_error("Archive File Error: First ZIP header extra field extends past archive bounds."); } validateEntryName( filename, "Archive File Error: First filename contains unsupported control characters.", "Archive Security Error: Unsafe first archive entry path detected"); return filename; } [[nodiscard]] bool isUnsafeEntryPath(std::string_view path) { if (path.empty()) { return true; } if (path.find('\\') != std::string::npos) { return true; } if (path[0] == '/') { return true; } if (path.size() >= 2 && std::isalpha(static_cast(path[0])) && path[1] == ':') { return true; } std::size_t segment_start = 0; for (std::size_t i = 0; i <= path.size(); ++i) { if (i < path.size() && path[i] != '/') { continue; } const std::string_view segment = path.substr(segment_start, i - segment_start); const bool trailing_directory_separator = (i == path.size() && segment.empty()); if (!trailing_directory_separator && (segment.empty() || segment == "."sv || segment == ".."sv || segment.back() == '.' || segment.back() == ' ' || hasWindowsInvalidPathCharacter(segment) || hasWindowsReservedSegmentName(segment))) { return true; } segment_start = i + 1; } return false; } [[nodiscard]] std::size_t findEndOfCentralDirectory(std::span archive_data) { constexpr std::size_t EOCD_MIN_SIZE = 22; if (archive_data.size() < ZIP_WRAP_PREFIX_SIZE + ZIP_WRAP_TRAILER_SIZE + EOCD_MIN_SIZE) { throw std::runtime_error("Archive File Error: Archive is too small."); } if (const auto eocd = findZipEocdLocator(archive_data, ZIP_WRAP_PREFIX_SIZE, archive_data.size() - ZIP_WRAP_TRAILER_SIZE)) { return eocd->index; } throw std::runtime_error("Archive File Error: End of central directory record not found."); } } // anonymous namespace ArchiveMetadata analyzeArchive(std::span archive_data, bool is_zip_file) { ArchiveMetadata metadata{ .file_type = FileType::UNKNOWN_FILE_TYPE, .first_filename = parseFirstZipFilename(archive_data) }; const std::string_view filename = metadata.first_filename; if (!is_zip_file) { if (filename != "META-INF/MANIFEST.MF" && filename != "META-INF/") { throw std::runtime_error("File Type Error: Archive does not appear to be a valid JAR file."); } metadata.file_type = FileType::JAR; return metadata; } // --- ZIP path: inspect the first record's filename/extension --- const bool is_folder = filename.back() == '/'; const std::size_t dot_pos = filename.rfind('.'); // Check for folders (entries ending with '/'). if (dot_pos == std::string_view::npos) { metadata.file_type = is_folder ? FileType::FOLDER : FileType::LINUX_EXECUTABLE; return metadata; } // A name with a dot could still be a folder if it ends with '/'. if (is_folder) { if (filename[filename.size() - 2] == '.') { throw std::runtime_error("ZIP File Error: Invalid folder name within ZIP archive."); } metadata.file_type = FileType::FOLDER; return metadata; } // Match extension against the known list. const std::string_view extension = filename.substr(dot_pos + 1); for (std::size_t i = 0; i < EXTENSION_LIST.size(); ++i) { if (std::ranges::equal(EXTENSION_LIST[i], extension, [](char lhs, char rhs) { return lhs == toLowerAscii(rhs); })) { // Indices 0..28 all map to VIDEO_AUDIO; 29+ map 1:1 with the enum. metadata.file_type = static_cast(std::max(i, static_cast(FileType::VIDEO_AUDIO))); return metadata; } } return metadata; } void validateArchiveEntryPaths(std::span archive_data) { const std::size_t eocd_index = findEndOfCentralDirectory(archive_data); const CentralDirectoryBounds central_directory = readCentralDirectoryBounds(archive_data, eocd_index); std::size_t cursor = central_directory.start; ArchiveEntryTracking tracking; tracking.reserve(central_directory.total_records); for (uint16_t i = 0; i < central_directory.total_records; ++i) { const CentralEntryMetadata entry = readCentralEntryMetadata( archive_data, cursor, i + 1); validateCentralEntryMetadata(entry, tracking); validateLocalEntryForCentralEntry( archive_data, central_directory.start, entry, tracking.local_spans); validateCentralRecordSpan(cursor, entry.record_size, central_directory.end, archive_data.size()); cursor = checkedAdd( cursor, entry.record_size, "Archive File Error: Central directory cursor overflow."); } if (cursor != central_directory.end) { throw std::runtime_error("Archive File Error: Central directory size does not match parsed records."); } validateLocalEntrySpans(tracking.local_spans); } ================================================ FILE: src/binary_utils.cpp ================================================ #include "pdvzip.h" namespace binary_utils_detail { [[noreturn]] void throwOutOfRange(std::string_view fn_name) { throw std::out_of_range(std::format("{}: index out of bounds", fn_name)); } } // namespace binary_utils_detail namespace { [[nodiscard]] bool isSupportedFieldLength(std::size_t length) { return length == 2 || length == 4; } void validateFieldBounds(std::size_t data_size, std::size_t offset, std::size_t length, std::string_view fn_name) { if (!isSupportedFieldLength(length)) { throw std::invalid_argument(std::format("{}: unsupported length {}", fn_name, length)); } if (offset > data_size || length > (data_size - offset)) { throw std::out_of_range(std::format("{}: index out of bounds", fn_name)); } } [[nodiscard]] std::size_t maxFieldValue(std::size_t length) { return (length == 2) ? static_cast(UINT16_MAX) : static_cast(UINT32_MAX); } [[nodiscard]] std::size_t fieldByteShift(std::size_t length, std::size_t index, std::endian byte_order) { return (byte_order == std::endian::big) ? ((length - 1 - index) * 8) : (index * 8); } } // anonymous namespace void writeValueAt( std::span data, std::size_t offset, std::size_t value, std::size_t length, std::endian byte_order) { validateFieldBounds(data.size(), offset, length, "writeValueAt"); if (value > maxFieldValue(length)) { throw std::out_of_range(std::format("writeValueAt: value {} exceeds {}-byte field", value, length)); } for (std::size_t i = 0; i < length; ++i) { data[offset + i] = static_cast((value >> fieldByteShift(length, i, byte_order)) & 0xFF); } } std::size_t readValueAt( std::span data, std::size_t offset, std::size_t length, std::endian byte_order) { validateFieldBounds(data.size(), offset, length, "readValueAt"); std::size_t value = 0; for (std::size_t i = 0; i < length; ++i) { value |= static_cast(data[offset + i]) << fieldByteShift(length, i, byte_order); } return value; } std::size_t checkedAdd(std::size_t lhs, std::size_t rhs, std::string_view context) { if (lhs > std::numeric_limits::max() - rhs) { throw std::runtime_error(std::string(context)); } return lhs + rhs; } std::size_t checkedMultiply(std::size_t lhs, std::size_t rhs, std::string_view context) { if (lhs != 0 && rhs > std::numeric_limits::max() / lhs) { throw std::runtime_error(std::string(context)); } return lhs * rhs; } std::optional findZipEocdLocator( std::span data, std::size_t archive_begin, std::size_t archive_end) { constexpr std::size_t EOCD_MIN_SIZE = 22, EOCD_SIGNATURE_SIZE = 4, EOCD_COMMENT_LENGTH_OFFSET = 20, MAX_EOCD_SEARCH_DISTANCE = EOCD_MIN_SIZE + static_cast(UINT16_MAX); if (archive_end > data.size() || archive_end < archive_begin || archive_end - archive_begin < EOCD_MIN_SIZE) { return std::nullopt; } const std::size_t distance_floor = (archive_end > MAX_EOCD_SEARCH_DISTANCE) ? archive_end - MAX_EOCD_SEARCH_DISTANCE : std::size_t{0}; const std::size_t search_floor = std::max(archive_begin, distance_floor); const std::size_t search_start = archive_end - EOCD_SIGNATURE_SIZE; if (search_start < search_floor) { return std::nullopt; } for (std::size_t pos = search_start; ; --pos) { if (hasLe32Signature(data, pos, ZIP_END_CENTRAL_DIRECTORY_SIGNATURE) && pos + EOCD_MIN_SIZE <= archive_end) { const uint16_t comment_length = readLe16(data, pos + EOCD_COMMENT_LENGTH_OFFSET); if (comment_length == archive_end - pos - EOCD_MIN_SIZE) { return ZipEocdLocator{ .index = pos, .comment_length = comment_length }; } } if (pos == search_floor) { break; } } return std::nullopt; } ================================================ FILE: src/compile_pdvzip.sh ================================================ #!/bin/bash # compile_pdvzip.sh — Build script for pdvzip (multi-file layout) set -euo pipefail CXX="${CXX:-g++}" CXXFLAGS="-std=c++23 -O3 -mtune=native -pipe -Wall -Wextra -Wpedantic -Wshadow -DNDEBUG -D_FORTIFY_SOURCE=3 -DLODEPNG_NO_COMPILE_DISK -DLODEPNG_NO_COMPILE_ANCILLARY_CHUNKS -s -flto=auto -fuse-linker-plugin -fstack-protector-strong -fPIE" LDFLAGS="-pie -Wl,-z,relro,-z,now" TARGET="pdvzip" SRCDIR="." SOURCES=( "$SRCDIR/main.cpp" "$SRCDIR/display_info.cpp" "$SRCDIR/program_args.cpp" "$SRCDIR/file_io.cpp" "$SRCDIR/binary_utils.cpp" "$SRCDIR/image_processing.cpp" "$SRCDIR/image_resize.cpp" "$SRCDIR/archive_analysis.cpp" "$SRCDIR/user_input.cpp" "$SRCDIR/script_builder.cpp" "$SRCDIR/script_text_builder.cpp" "$SRCDIR/polyglot_assembly.cpp" "$SRCDIR/lodepng/lodepng.cpp" ) echo "Compiling $TARGET..." $CXX $CXXFLAGS "${SOURCES[@]}" $LDFLAGS -o "$TARGET" echo "Compilation successful. Executable '$TARGET' created." ================================================ FILE: src/display_info.cpp ================================================ #include "pdvzip.h" void displayInfo() { std::print(R"( PNG Data Vehicle ZIP/JAR Edition (PDVZIP v4.5). Created by Nicholas Cleasby (@CleasbyCode) 6/08/2022. Use PDVZIP to embed a ZIP/JAR file within a PNG image, to create a tweetable and "executable" PNG-ZIP/JAR polyglot file. The supported hosting sites will retain the embedded archive within the PNG image. PNG image size limits are platform dependant: X/Twitter (5MB), Flickr (200MB), Imgbb (32MB), PostImage (32MB), ImgPile (8MB). Once the ZIP file has been embedded within a PNG image, it can be shared on your chosen hosting site or 'executed' whenever you want to access the embedded file(s). pdvzip (Linux) will attempt to automatically set executable permissions on newly created polyglot image files. You will need to manually set executable permissions using chmod on these polyglot images downloaded from hosting sites. From a Linux terminal: ./pzip_image.png (chmod +x pzip_image.png, if required). From a Windows terminal: First, rename the '.png' file extension to '.cmd', then .\pzip_image.cmd For common video/audio files, Linux uses the media player vlc or mpv. Windows uses the set default media player. PDF, Linux uses either evince or firefox. Windows uses the set default PDF viewer. Python, Linux & Windows use python3 to run these programs. PowerShell, Linux uses pwsh command (if PowerShell installed). Depending on the installed version of PowerShell, Windows uses either pwsh.exe or powershell.exe, to run these scripts. Folder, Linux uses xdg-open, Windows uses powershell.exe with II (Invoke-Item) command, to open zipped folders. For any other media type/file extension, Linux & Windows will rely on the operating system's method or set default application for those files. PNG Image Requirements for Arbitrary Data Preservation PNG file size (image + embedded content) must not exceed the hosting site's size limits. The site will either refuse to upload your image or it will convert your image to jpg, such as X/Twitter. Dimensions: The following dimension size limits are specific to pdvzip and not necessarily the exact hosting site's size limits. PNG-32/24 (Truecolor) Image dimensions can be set between a minimum of 68x68 and a maximum of 900x900. These dimension size limits are for compatibility reasons, allowing it to work with all the above listed platforms. Note: Images that are created & saved within your image editor as PNG-32/24 that are either black & white/grayscale, images with 256 colours or less, will be converted by X/Twitter to PNG-8 and you will lose the embedded content. If you want to use a simple "single" colour PNG-32/24 image, then fill an area with a gradient colour instead of a single solid colour. X/Twitter should then keep the image as PNG-32/24. PNG-8 (Indexed-colour) Image dimensions can be set between a minimum of 68x68 and a maximum of 4096x4096. PNG Chunks: For example, with X/Twitter, you can overfill the following PNG chunks with arbitrary data, in which the platform will preserve as long as you keep within the image dimension & file size limits. Other platforms may differ in what chunks they preserve and which you can overfill. bKGD, cHRM, gAMA, hIST, iCCP, (Only 10KB max. with X/Twitter). IDAT, (Use as last IDAT chunk, after the final image IDAT chunk). PLTE, (Use only with PNG-32 & PNG-24 for arbitrary data). pHYs, sBIT, sPLT, sRGB, tRNS. (PNG-32 only). This program uses the iCCP (extraction script) and IDAT (zip file) chunk names for storing arbitrary data. ZIP File Size & Other Information To work out the maximum ZIP file size, start with the hosting site's size limit, minus your PNG image size, minus 1500 bytes (extraction script size). X/Twitter example: (5MB Image Limit) 5,242,880 - (image size 307,200 + extraction script size 1500) = 4,934,180 bytes available for your ZIP file. Make sure ZIP file is a standard ZIP archive, compatible with Linux unzip & Windows Explorer. Do not include other .zip files within the main ZIP archive. (.rar files are ok). Do not include other pdvzip created PNG image files within the main ZIP archive, as they are essentially .zip files. Use file extensions for your media file within the ZIP archive: my_doc.pdf, my_video.mp4, my_program.py, etc. A file without an extension will be treated as a Linux executable. Paint.net application is recommended for easily creating compatible PNG image files. )"); } ================================================ FILE: src/file_io.cpp ================================================ #include "pdvzip.h" namespace { [[nodiscard]] bool equalsIgnoreAsciiCase(std::string_view lhs, std::string_view rhs) { return std::ranges::equal(lhs, rhs, [](unsigned char a, unsigned char b) { return std::tolower(a) == std::tolower(b); }); } } // anonymous namespace bool hasValidFilename(const fs::path& p) { const auto filename = p.filename().string(); return !filename.empty() && std::ranges::none_of(filename, [](unsigned char c) { return std::iscntrl(c) != 0; }); } bool hasFileExtension(const fs::path& p, std::initializer_list exts) { const std::string extension = p.extension().string(); return std::ranges::any_of(exts, [&extension](std::string_view ext) { return equalsIgnoreAsciiCase(extension, ext); }); } namespace { struct ScopedFd { int fd{-1}; explicit ScopedFd(int file_descriptor) noexcept : fd(file_descriptor) {} ~ScopedFd() { if (fd >= 0) { ::close(fd); } } ScopedFd(const ScopedFd&) = delete; ScopedFd& operator=(const ScopedFd&) = delete; ScopedFd(ScopedFd&& other) noexcept : fd(other.fd) { other.fd = -1; } ScopedFd& operator=(ScopedFd&& other) noexcept { if (this != &other) { if (fd >= 0) { ::close(fd); } fd = other.fd; other.fd = -1; } return *this; } [[nodiscard]] int get() const noexcept { return fd; } }; [[nodiscard]] ScopedFd openFileForReadOrThrow(const fs::path& path) { int flags = O_RDONLY | O_CLOEXEC; #ifdef O_NOFOLLOW flags |= O_NOFOLLOW; #endif ScopedFd handle(::open(path.c_str(), flags)); if (handle.get() < 0) { const std::error_code ec(errno, std::generic_category()); throw std::runtime_error(std::format( "Failed to open file: {} ({})", path.string(), ec.message())); } return handle; } [[nodiscard]] std::size_t fdFileSizeChecked(int fd, const fs::path& path) { struct stat st{}; if (::fstat(fd, &st) != 0) { const std::error_code ec(errno, std::generic_category()); throw std::runtime_error(std::format( "Error: Failed to stat \"{}\": {}", path.string(), ec.message())); } if (!S_ISREG(st.st_mode)) { throw std::runtime_error(std::format( "Error: File \"{}\" not found or not a regular file.", path.string())); } if (st.st_size < 0) { throw std::runtime_error(std::format( "Error: Negative file size reported for \"{}\".", path.string())); } const auto raw_file_size = static_cast(st.st_size); if (raw_file_size > std::numeric_limits::max()) { throw std::runtime_error("Error: File is too large to process on this platform."); } const std::size_t file_size = static_cast(raw_file_size); if (!file_size) { throw std::runtime_error("Error: File is empty."); } return file_size; } void validateCoverImageConstraints(const fs::path& path, std::size_t file_size) { // Smallest representable PNG: 8-byte signature + 25-byte IHDR + 12-byte IEND // + a minimal IDAT chunk; this is the practical floor below which the file // cannot be a valid PNG. constexpr std::size_t MIN_PNG_SIZE = 87; constexpr std::size_t MAX_COVER_IMAGE_SIZE = 4 * 1024 * 1024; if (!hasFileExtension(path, {".png"})) { throw std::runtime_error("Image File Error: Invalid image extension. Only expecting \".png\"."); } if (file_size < MIN_PNG_SIZE) { throw std::runtime_error("Image File Error: Cover image too small. Not a valid PNG."); } if (file_size > MAX_COVER_IMAGE_SIZE) { throw std::runtime_error("Image File Error: Cover image exceeds the 4MB size limit."); } } void validateArchiveConstraints(const fs::path& path, std::size_t file_size) { // PNG chunk lengths are 31-bit per the PNG specification. Keep the ZIP // payload within the range this program can emit as the final IDAT chunk. constexpr std::size_t MAX_ARCHIVE_SIZE = static_cast(std::numeric_limits::max()); if (!hasFileExtension(path, {".zip", ".jar"})) { throw std::runtime_error("Archive File Error: Invalid file extension. Only expecting \".zip\" or \".jar\"."); } if (file_size < 30) { throw std::runtime_error("Archive File Error: Invalid file size."); } if (file_size > MAX_ARCHIVE_SIZE) { throw std::runtime_error("Archive File Error: File exceeds maximum size limit."); } } void validateTypeSpecificConstraints(const fs::path& path, std::size_t file_size, FileTypeCheck check_type) { if (check_type == FileTypeCheck::cover_image) { validateCoverImageConstraints(path, file_size); } else if (check_type == FileTypeCheck::archive_file) { validateArchiveConstraints(path, file_size); } } [[nodiscard]] vBytes makeReadBuffer(std::size_t file_size, bool wrap_archive) { const std::size_t prefix_size = wrap_archive ? 8 : 0; const std::size_t buffer_size = wrap_archive ? checkedAdd(file_size, CHUNK_FIELDS_COMBINED_LENGTH, "Archive File Error: Wrapped archive size overflow.") : file_size; vBytes vec(buffer_size, 0); if (wrap_archive) { constexpr auto IDAT_MARKER_BYTES = std::to_array({ 0x00, 0x00, 0x00, 0x00, 0x49, 0x44, 0x41, 0x54 }); std::copy(IDAT_MARKER_BYTES.begin(), IDAT_MARKER_BYTES.end(), vec.begin()); } if (prefix_size > vec.size()) { throw std::runtime_error("Archive File Error: Wrapped archive prefix overflow."); } return vec; } void readFileContents(int fd, const fs::path& path, vBytes& vec, std::size_t file_size, bool wrap_archive) { const std::size_t prefix_size = wrap_archive ? 8 : 0; std::size_t total_read = 0; while (total_read < file_size) { const std::size_t remaining = file_size - total_read; const std::size_t chunk = std::min( remaining, static_cast(std::numeric_limits::max())); const ssize_t rc = ::read(fd, vec.data() + prefix_size + total_read, chunk); if (rc < 0) { if (errno == EINTR) { continue; } const std::error_code ec(errno, std::generic_category()); throw std::runtime_error(std::format( "Failed to read file: {} ({})", path.string(), ec.message())); } if (rc == 0) { throw std::runtime_error("Failed to read full file: partial read"); } total_read += static_cast(rc); } } void validateWrappedArchiveSignature(const vBytes& vec, bool wrap_archive) { if (wrap_archive && !hasLe32Signature(vec, 8, ZIP_LOCAL_FILE_HEADER_SIGNATURE)) { throw std::runtime_error("Archive File Error: Signature check failure. Not a valid archive file."); } } } // anonymous namespace vBytes readFile(const fs::path& path, FileTypeCheck check_type) { if (!hasValidFilename(path)) { throw std::runtime_error("Invalid Input Error: Filename contains unsupported control characters."); } // Open the file first, then validate via fstat on the resulting fd. This // avoids a TOCTOU race where a stat-then-open pair could observe a // different file than the one ultimately read. const ScopedFd handle = openFileForReadOrThrow(path); const std::size_t file_size = fdFileSizeChecked(handle.get(), path); validateTypeSpecificConstraints(path, file_size, check_type); const bool wrap_archive = (check_type == FileTypeCheck::archive_file); vBytes vec = makeReadBuffer(file_size, wrap_archive); readFileContents(handle.get(), path, vec, file_size, wrap_archive); validateWrappedArchiveSignature(vec, wrap_archive); return vec; } void writePolyglotFile(const vBytes& image_vec, bool is_zip_file) { if (image_vec.size() > static_cast(std::numeric_limits::max())) { throw std::runtime_error("Write File Error: Output exceeds maximum writable size."); } std::random_device rd; std::mt19937 gen(rd()); std::uniform_int_distribution<> dist(10000, 99999); const std::string_view prefix = is_zip_file ? "pzip_" : "pjar_"; constexpr std::size_t MAX_NAME_ATTEMPTS = 256; std::string filename; std::ofstream ofs; for (std::size_t i = 0; i < MAX_NAME_ATTEMPTS; ++i) { filename = std::format("{}{}.png", prefix, dist(gen)); // noreplace (C++23) atomically fails if the file already exists, // eliminating the TOCTOU race between exists() and open(). ofs.open(filename, std::ios::binary | std::ios::out | std::ios::noreplace); if (ofs) { break; } ofs.clear(); } if (!ofs) { throw std::runtime_error("Write File Error: Unable to create a unique output file."); } ofs.write(reinterpret_cast(image_vec.data()), static_cast(image_vec.size())); if (!ofs) { throw std::runtime_error("Write File Error: Failed while writing output file."); } ofs.close(); if (!ofs) { throw std::runtime_error("Write File Error: Failed while finalizing output file."); } // Fsync the output to disk so the polyglot survives a power loss between // here and the kernel's writeback. The fd is reopened just for the sync — // std::ofstream doesn't expose its underlying descriptor portably. { ScopedFd sync_fd(::open(filename.c_str(), O_RDONLY | O_CLOEXEC)); if (sync_fd.get() >= 0) { ::fsync(sync_fd.get()); } } std::print("\nCreated {} polyglot image file: {} ({} bytes).\n\nComplete!\n\n", is_zip_file ? "PNG-ZIP" : "PNG-JAR", filename, image_vec.size()); std::error_code ec; fs::permissions( filename, fs::perms::owner_all | fs::perms::group_read | fs::perms::group_exec | fs::perms::others_read | fs::perms::others_exec, ec); if (ec) { std::println(stderr, "\nWarning: Could not set executable permissions for {}.\n" "You may need to do this manually with: chmod +x \"{}\"", filename, filename); } } ================================================ FILE: src/image_processing.cpp ================================================ #include "image_processing_internal.h" using image_processing_internal::copyPalette; using image_processing_internal::resizeImage; using image_processing_internal::throwLodepngError; namespace { constexpr std::size_t RGBA_COMPONENTS = image_processing_internal::RGBA_COMPONENTS; [[nodiscard]] constexpr std::uint32_t pngChunkType(char a, char b, char c, char d) { return (static_cast(static_cast(a)) << 24) | (static_cast(static_cast(b)) << 16) | (static_cast(static_cast(c)) << 8) | static_cast(static_cast(d)); } [[nodiscard]] constexpr std::uint32_t packRgbaKey(Byte red, Byte green, Byte blue, Byte alpha) { return (static_cast(red) << 24) | (static_cast(green) << 16) | (static_cast(blue) << 8) | static_cast(alpha); } struct PngIhdr { std::size_t width; std::size_t height; Byte bit_depth; Byte color_type; }; constexpr uint16_t MIN_RGB_COLORS = 257, MIN_SAFE_DIMENSION = 68, MAX_PLTE_DIMENSION = 4096, MAX_RGB_DIMENSION = 900, MAX_RESIZE_ITERATIONS = 200; constexpr std::size_t IHDR_WIDTH_START = 0x10, IHDR_HEIGHT_END = 0x18, // Exclusive: covers width (0x10..0x13) + height (0x14..0x17). IHDR_CRC_START = 0x1D, IHDR_CRC_END = 0x21; // Exclusive. class PaletteIndexTable { static constexpr std::size_t TABLE_SIZE = 512; static constexpr std::size_t TABLE_MASK = TABLE_SIZE - 1; std::array keys_{}; std::array values_{}; std::array occupied_{}; [[nodiscard]] static constexpr std::size_t hash(std::uint32_t key) { key ^= key >> 16; key *= 0x7feb352dU; key ^= key >> 15; key *= 0x846ca68bU; key ^= key >> 16; return static_cast(key) & TABLE_MASK; } public: void insertIfAbsent(std::uint32_t key, Byte value) { std::size_t slot = hash(key); for (std::size_t probe = 0; probe < TABLE_SIZE; ++probe) { if (!occupied_[slot]) { occupied_[slot] = true; keys_[slot] = key; values_[slot] = value; return; } if (keys_[slot] == key) { return; } slot = (slot + 1) & TABLE_MASK; } throw std::runtime_error("convertToPalette: Palette lookup table is full."); } [[nodiscard]] bool find(std::uint32_t key, Byte& value) const { std::size_t slot = hash(key); for (std::size_t probe = 0; probe < TABLE_SIZE; ++probe) { if (!occupied_[slot]) { return false; } if (keys_[slot] == key) { value = values_[slot]; return true; } slot = (slot + 1) & TABLE_MASK; } return false; } }; [[nodiscard]] PngIhdr readPngIhdr(std::span png_data) { constexpr auto PNG_SIG = std::to_array({ 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A }); constexpr std::size_t MIN_IHDR_TOTAL_SIZE = 33, IHDR_LENGTH_INDEX = 8, IHDR_NAME_INDEX = 12, WIDTH_INDEX = 16, HEIGHT_INDEX = 20, BIT_DEPTH_INDEX = 24, COLOR_TYPE_INDEX = 25; if (png_data.size() < MIN_IHDR_TOTAL_SIZE) { throw std::runtime_error("PNG Error: File too small to contain a valid IHDR chunk."); } if (!std::equal(PNG_SIG.begin(), PNG_SIG.end(), png_data.begin())) { throw std::runtime_error("PNG Error: Invalid signature."); } if (readValueAt(png_data, IHDR_NAME_INDEX, 4) != pngChunkType('I', 'H', 'D', 'R')) { throw std::runtime_error("PNG Error: First chunk is not IHDR."); } if (readValueAt(png_data, IHDR_LENGTH_INDEX, 4) != 13) { throw std::runtime_error("PNG Error: IHDR chunk length is invalid."); } return PngIhdr{ .width = readValueAt(png_data, WIDTH_INDEX, 4), .height = readValueAt(png_data, HEIGHT_INDEX, 4), .bit_depth = png_data[BIT_DEPTH_INDEX], .color_type = png_data[COLOR_TYPE_INDEX] }; } void validateInputPngForDecode(const PngIhdr& ihdr) { constexpr std::size_t MIN_DIMENSION = 68, MAX_DIMENSION = 4096; const bool supported_color_type = ihdr.color_type == INDEXED_PLTE || ihdr.color_type == TRUECOLOR_RGB || ihdr.color_type == TRUECOLOR_RGBA; if (!supported_color_type) { throw std::runtime_error("Image File Error: Unsupported PNG color type."); } const bool supported_bit_depth = (ihdr.color_type == INDEXED_PLTE && (ihdr.bit_depth == 1 || ihdr.bit_depth == 2 || ihdr.bit_depth == 4 || ihdr.bit_depth == 8)) || ((ihdr.color_type == TRUECOLOR_RGB || ihdr.color_type == TRUECOLOR_RGBA) && ihdr.bit_depth == 8); if (!supported_bit_depth) { throw std::runtime_error("Image File Error: Unsupported PNG bit depth."); } if (ihdr.width < MIN_DIMENSION || ihdr.height < MIN_DIMENSION) { throw std::runtime_error("Image File Error: Cover image dimensions are too small."); } if (ihdr.width > MAX_DIMENSION || ihdr.height > MAX_DIMENSION) { throw std::runtime_error("Image File Error: Cover image dimensions exceed the supported limit."); } } // ============================================================================ // Internal: Convert truecolor image to indexed palette // ============================================================================ void convertToPalette( vBytes& image_file_vec, const vBytes& image, unsigned width, unsigned height, const LodePNGColorStats& stats, LodePNGColorType raw_color_type) { constexpr Byte PALETTE_BIT_DEPTH = 8, ALPHA_OPAQUE = 255; constexpr std::size_t RGB_COMPONENTS = 3, MAX_PALETTE_SIZE = 256; // Validate color type — this function only handles RGB and RGBA input. if (raw_color_type != LCT_RGB && raw_color_type != LCT_RGBA) { throw std::runtime_error(std::format( "convertToPalette: Unsupported color type {}. Expected RGB or RGBA.", static_cast(raw_color_type))); } const std::size_t palette_size = stats.numcolors; if (palette_size == 0) { throw std::runtime_error("convertToPalette: Palette is empty."); } if (palette_size > MAX_PALETTE_SIZE) { throw std::runtime_error(std::format( "convertToPalette: Palette has {} colors, exceeds maximum of {}.", palette_size, MAX_PALETTE_SIZE)); } const std::size_t channels = (raw_color_type == LCT_RGBA) ? RGBA_COMPONENTS : RGB_COMPONENTS; PaletteIndexTable color_to_index; for (std::size_t i = 0; i < palette_size; ++i) { const Byte* src = &stats.palette[i * RGBA_COMPONENTS]; color_to_index.insertIfAbsent(packRgbaKey(src[0], src[1], src[2], src[3]), static_cast(i)); } // Map each pixel to its palette index. const std::size_t pixel_count = checkedMultiply( static_cast(width), static_cast(height), "Image Error: Indexed image dimensions overflow."); const std::size_t image_span = checkedMultiply( pixel_count, channels, "Image Error: Indexed image byte span overflow."); if (image.size() < image_span) { throw std::runtime_error("Image Error: Decoded image buffer is truncated."); } vBytes indexed_image(pixel_count); const Byte* pixel = image.data(); for (std::size_t i = 0; i < pixel_count; ++i) { const std::uint32_t key = packRgbaKey( pixel[0], pixel[1], pixel[2], (channels == RGBA_COMPONENTS) ? pixel[3] : ALPHA_OPAQUE ); Byte palette_index = 0; if (!color_to_index.find(key, palette_index)) { throw std::runtime_error(std::format( "convertToPalette: Pixel {} has color 0x{:08X} not found in palette.", i, key)); } indexed_image[i] = palette_index; pixel += channels; } // Encode as 8-bit palette PNG. lodepng::State encode_state; encode_state.info_raw.colortype = LCT_PALETTE; encode_state.info_raw.bitdepth = PALETTE_BIT_DEPTH; encode_state.info_png.color.colortype = LCT_PALETTE; encode_state.info_png.color.bitdepth = PALETTE_BIT_DEPTH; encode_state.encoder.auto_convert = 0; copyPalette(stats.palette, palette_size, encode_state.info_png.color); copyPalette(stats.palette, palette_size, encode_state.info_raw); vBytes output; unsigned error = lodepng::encode(output, indexed_image.data(), width, height, encode_state); throwLodepngError("LodePNG encode error", error); image_file_vec = std::move(output); } // ============================================================================ // Internal: Strip non-essential chunks, keeping only IHDR, PLTE, tRNS, IDAT, IEND // ============================================================================ void stripAndCopyChunks(vBytes& image_file_vec, Byte color_type) { constexpr std::uint32_t IHDR_TYPE = pngChunkType('I', 'H', 'D', 'R'), PLTE_TYPE = pngChunkType('P', 'L', 'T', 'E'), TRNS_TYPE = pngChunkType('t', 'R', 'N', 'S'), IDAT_TYPE = pngChunkType('I', 'D', 'A', 'T'), IEND_TYPE = pngChunkType('I', 'E', 'N', 'D'); constexpr std::size_t PNG_SIGNATURE_SIZE = 8, CHUNK_OVERHEAD = 12, // length(4) + name(4) + crc(4) LENGTH_FIELD_SIZE = 4, TYPE_FIELD_SIZE = 4; // In-place memmove compaction: walk chunks once, shifting kept chunks toward // the front. Avoids allocating a second image-sized buffer. std::size_t read_pos = PNG_SIGNATURE_SIZE; std::size_t write_pos = PNG_SIGNATURE_SIZE; bool saw_idat = false; bool saw_iend = false; while (read_pos < image_file_vec.size()) { if (CHUNK_OVERHEAD > image_file_vec.size() - read_pos) { throw std::runtime_error("PNG Error: Truncated chunk header."); } const std::size_t data_length = readValueAt(image_file_vec, read_pos, LENGTH_FIELD_SIZE); if (data_length > image_file_vec.size() - read_pos - CHUNK_OVERHEAD) { throw std::runtime_error(std::format( "PNG Error: Chunk at offset 0x{:X} exceeds file size.", read_pos)); } const std::size_t name_index = read_pos + LENGTH_FIELD_SIZE; const std::uint32_t chunk_type = static_cast( readValueAt(image_file_vec, name_index, TYPE_FIELD_SIZE)); const bool is_idat = chunk_type == IDAT_TYPE; const bool is_iend = chunk_type == IEND_TYPE; const bool keep_chunk = chunk_type == IHDR_TYPE || is_idat || is_iend || chunk_type == TRNS_TYPE || (color_type == INDEXED_PLTE && chunk_type == PLTE_TYPE); const std::size_t total_chunk_size = CHUNK_OVERHEAD + data_length; if (keep_chunk) { if (write_pos != read_pos) { std::memmove( image_file_vec.data() + write_pos, image_file_vec.data() + read_pos, total_chunk_size); } write_pos += total_chunk_size; } saw_idat = saw_idat || is_idat; read_pos += total_chunk_size; if (is_iend) { saw_iend = true; break; } } if (!saw_idat) { throw std::runtime_error("PNG Error: No IDAT chunk found."); } if (!saw_iend) { throw std::runtime_error("PNG Error: Missing IEND chunk."); } image_file_vec.resize(write_pos); } [[nodiscard]] bool canConvertToPalette(Byte input_color_type, const LodePNGColorStats& stats) { return (input_color_type == TRUECOLOR_RGB || input_color_type == TRUECOLOR_RGBA) && (stats.numcolors < MIN_RGB_COLORS); } [[nodiscard]] bool pngRangeHasProblemCharacter(std::span png_data, std::size_t start, std::size_t end) { const auto bytes = png_data.subspan(start, end - start); return std::ranges::any_of(bytes, isLinuxProblemMetacharacter); } [[nodiscard]] bool ihdrHasLinuxProblemCharacter(std::span png_data) { if (png_data.size() < IHDR_CRC_END) { throw std::runtime_error("PNG Error: IHDR chunk is truncated after optimization."); } return pngRangeHasProblemCharacter(png_data, IHDR_WIDTH_START, IHDR_HEIGHT_END) || pngRangeHasProblemCharacter(png_data, IHDR_CRC_START, IHDR_CRC_END); } [[nodiscard]] bool candidateIhdrIsLinuxSafe(unsigned width, unsigned height, Byte bit_depth, Byte color_type) { Byte ihdr[17] = { 'I', 'H', 'D', 'R', static_cast((width >> 24) & 0xFF), static_cast((width >> 16) & 0xFF), static_cast((width >> 8) & 0xFF), static_cast(width & 0xFF), static_cast((height >> 24) & 0xFF), static_cast((height >> 16) & 0xFF), static_cast((height >> 8) & 0xFF), static_cast(height & 0xFF), bit_depth, color_type, 0, 0, 0 // compression, filter, interlace - lodepng default is 0 for all. }; const auto dimension_bytes = std::span(ihdr).subspan(4, 8); if (std::ranges::any_of(dimension_bytes, isLinuxProblemMetacharacter)) { return false; } const uint32_t crc = lodepng_crc32(ihdr, sizeof(ihdr)); const Byte crc_bytes[4] = { static_cast((crc >> 24) & 0xFF), static_cast((crc >> 16) & 0xFF), static_cast((crc >> 8) & 0xFF), static_cast(crc & 0xFF), }; return !std::ranges::any_of(crc_bytes, isLinuxProblemMetacharacter); } [[nodiscard]] std::optional> findLinuxSafeResizeTarget(const PngIhdr& current) { for (unsigned delta = 1; delta <= MAX_RESIZE_ITERATIONS; ++delta) { if (current.width < MIN_SAFE_DIMENSION + delta || current.height < MIN_SAFE_DIMENSION + delta) { break; } const unsigned width = static_cast(current.width) - delta; const unsigned height = static_cast(current.height) - delta; if (candidateIhdrIsLinuxSafe(width, height, current.bit_depth, current.color_type)) { return std::make_pair(width, height); } } return std::nullopt; } void ensureLinuxSafeIhdr(vBytes& image_file_vec) { if (!ihdrHasLinuxProblemCharacter(image_file_vec)) { return; } const PngIhdr current = readPngIhdr(image_file_vec); const auto target = findLinuxSafeResizeTarget(current); if (!target) { throw std::runtime_error( "Image Error: Could not eliminate problem characters from IHDR " "within the resize iteration limit."); } resizeImage(image_file_vec, target->first, target->second); // Sanity-check that the encoder produced the IHDR we predicted. if (ihdrHasLinuxProblemCharacter(image_file_vec)) { throw std::runtime_error( "Image Error: Post-resize IHDR still contains problem characters. " "Encoder produced an unexpected IHDR layout."); } } [[nodiscard]] std::size_t maxDimensionForColorType(Byte color_type) { if (color_type == INDEXED_PLTE) { return MAX_PLTE_DIMENSION; } if (color_type == TRUECOLOR_RGB || color_type == TRUECOLOR_RGBA) { return MAX_RGB_DIMENSION; } return 0; } void validateFinalImageCompatibility(const PngIhdr& ihdr) { const std::size_t max_dimension = maxDimensionForColorType(ihdr.color_type); const bool has_valid_dimensions = max_dimension != 0 && ihdr.width >= MIN_SAFE_DIMENSION && ihdr.width <= max_dimension && ihdr.height >= MIN_SAFE_DIMENSION && ihdr.height <= max_dimension; if (has_valid_dimensions) { return; } if (max_dimension == 0) { std::print(stderr, "\nImage File Error: Color type of cover image is not supported.\n\n" "Supported types: PNG-32/24 (Truecolor) or PNG-8 (Indexed-Color)."); } else { std::print(stderr, "\nImage File Error: Dimensions of cover image are not within the supported range.\n\n" "Supported ranges:\n" " - PNG-32/24 Truecolor: [68 x 68] to [900 x 900]\n" " - PNG-8 Indexed-Color: [68 x 68] to [4096 x 4096]\n"); } throw std::runtime_error("Incompatible image. Aborting."); } } // anonymous namespace // ============================================================================ // Public: Optimize image for polyglot embedding // ============================================================================ void optimizeImage(vBytes& image_file_vec) { validateInputPngForDecode(readPngIhdr(image_file_vec)); lodepng::State state; vBytes image; unsigned width = 0; unsigned height = 0; unsigned error = lodepng::decode(image, width, height, state, image_file_vec); throwLodepngError("LodePNG decode error", error, true); LodePNGColorStats stats; lodepng_color_stats_init(&stats); stats.allow_palette = 1; stats.allow_greyscale = 0; error = lodepng_compute_color_stats(&stats, image.data(), width, height, &state.info_raw); throwLodepngError("LodePNG stats error", error); const Byte input_color_type = static_cast(state.info_png.color.colortype); if (canConvertToPalette(input_color_type, stats)) { convertToPalette(image_file_vec, image, width, height, stats, state.info_raw.colortype); } else { stripAndCopyChunks(image_file_vec, input_color_type); } // Problem metacharacters can appear in IHDR width/height bytes or the IHDR CRC // and break the Linux extraction script. Compute safe dimensions analytically // over a 17-byte scratch buffer, then resize at most once — far cheaper than // repeatedly decoding and re-encoding the whole PNG. // Checked ranges: width+height at 0x10..0x17 and CRC at 0x1D..0x20. ensureLinuxSafeIhdr(image_file_vec); validateFinalImageCompatibility(readPngIhdr(image_file_vec)); } ================================================ FILE: src/image_processing_internal.h ================================================ #pragma once #include "pdvzip.h" namespace image_processing_internal { constexpr std::size_t RGBA_COMPONENTS = 4; inline void throwLodepngError(std::string_view context, unsigned error, bool include_error_text = false) { if (!error) return; throw std::runtime_error(include_error_text ? std::format("{} {}: {}", context, error, lodepng_error_text(error)) : std::format("{}: {}", context, error)); } inline void copyPalette(const Byte* palette, std::size_t count, LodePNGColorMode& target) { if (count > 0 && palette == nullptr) { throw std::runtime_error("LodePNG palette setup error: source palette is null"); } for (std::size_t i = 0; i < count; ++i) { const Byte* p = &palette[i * RGBA_COMPONENTS]; throwLodepngError("LodePNG palette setup error", lodepng_palette_add(&target, p[0], p[1], p[2], p[3])); } } void resizeImage(vBytes& image_file_vec, unsigned new_width, unsigned new_height); } // namespace image_processing_internal ================================================ FILE: src/image_resize.cpp ================================================ #include "image_processing_internal.h" #if defined(__SSE2__) || defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 2) #include #define PDVZIP_HAS_X86_SIMD 1 #else #define PDVZIP_HAS_X86_SIMD 0 #endif namespace { struct ResizeAxisSample { unsigned lower{}; unsigned upper{}; unsigned nearest{}; float lower_weight{}; float upper_weight{}; }; [[nodiscard]] std::vector buildResizeAxisSamples(unsigned source_size, unsigned target_size) { constexpr double SAMPLING_OFFSET = 0.5; std::vector samples(target_size); const double ratio = static_cast(source_size) / static_cast(target_size); for (unsigned i = 0; i < target_size; ++i) { const double source_position = std::clamp( (i + SAMPLING_OFFSET) * ratio - SAMPLING_OFFSET, 0.0, static_cast(source_size - 1) ); const unsigned lower = static_cast(source_position); const float upper_weight = static_cast(source_position - static_cast(lower)); samples[i] = ResizeAxisSample{ .lower = lower, .upper = std::min(lower + 1, source_size - 1), .nearest = static_cast(std::round(source_position)), .lower_weight = 1.0f - upper_weight, .upper_weight = upper_weight }; } return samples; } template inline void interpolatePixelScalar( Byte* destination, const Byte* top_left, const Byte* top_right, const Byte* bottom_left, const Byte* bottom_right, float top_left_weight, float top_right_weight, float bottom_left_weight, float bottom_right_weight ) { for (unsigned channel = 0; channel < Channels; ++channel) { const float value = top_left_weight * static_cast(top_left[channel]) + top_right_weight * static_cast(top_right[channel]) + bottom_left_weight * static_cast(bottom_left[channel]) + bottom_right_weight * static_cast(bottom_right[channel]); destination[channel] = static_cast(std::clamp(std::round(value), 0.0f, 255.0f)); } } #if PDVZIP_HAS_X86_SIMD template [[nodiscard]] inline __m128 loadPixelAsFloat(const Byte* source) { if constexpr (Channels == 4) { return _mm_setr_ps( static_cast(source[0]), static_cast(source[1]), static_cast(source[2]), static_cast(source[3])); } else { return _mm_setr_ps( static_cast(source[0]), static_cast(source[1]), static_cast(source[2]), 0.0f); } } template inline void storeRoundedPixel(Byte* destination, __m128 value) { const __m128 clamped = _mm_min_ps(_mm_max_ps(value, _mm_setzero_ps()), _mm_set1_ps(255.0f)); const __m128 biased = _mm_add_ps(clamped, _mm_set1_ps(0.5f)); const __m128i rounded = _mm_cvttps_epi32(biased); alignas(16) int components[4]{}; _mm_storeu_si128(reinterpret_cast<__m128i*>(components), rounded); for (unsigned channel = 0; channel < Channels; ++channel) { destination[channel] = static_cast(components[channel]); } } template inline void interpolatePixelSimd( Byte* destination, const Byte* top_left, const Byte* top_right, const Byte* bottom_left, const Byte* bottom_right, float top_left_weight, float top_right_weight, float bottom_left_weight, float bottom_right_weight ) { const __m128 sum = _mm_add_ps( _mm_add_ps( _mm_mul_ps(loadPixelAsFloat(top_left), _mm_set1_ps(top_left_weight)), _mm_mul_ps(loadPixelAsFloat(top_right), _mm_set1_ps(top_right_weight))), _mm_add_ps( _mm_mul_ps(loadPixelAsFloat(bottom_left), _mm_set1_ps(bottom_left_weight)), _mm_mul_ps(loadPixelAsFloat(bottom_right), _mm_set1_ps(bottom_right_weight)))); storeRoundedPixel(destination, sum); } #endif template inline void interpolatePixel( Byte* destination, const Byte* top_left, const Byte* top_right, const Byte* bottom_left, const Byte* bottom_right, float top_left_weight, float top_right_weight, float bottom_left_weight, float bottom_right_weight ) { #if PDVZIP_HAS_X86_SIMD interpolatePixelSimd( destination, top_left, top_right, bottom_left, bottom_right, top_left_weight, top_right_weight, bottom_left_weight, bottom_right_weight); #else interpolatePixelScalar( destination, top_left, top_right, bottom_left, bottom_right, top_left_weight, top_right_weight, bottom_left_weight, bottom_right_weight); #endif } void resizePaletteImage( vBytes& resized, const vBytes& pixels, unsigned width, unsigned new_width, unsigned new_height, const std::vector& x_samples, const std::vector& y_samples ) { for (unsigned y = 0; y < new_height; ++y) { const std::size_t source_row = static_cast(y_samples[y].nearest) * width; Byte* const destination_row = resized.data() + static_cast(y) * new_width; for (unsigned x = 0; x < new_width; ++x) { destination_row[x] = pixels[source_row + x_samples[x].nearest]; } } } template void resizeTruecolorImage( vBytes& resized, const vBytes& pixels, unsigned width, unsigned new_width, unsigned new_height, const std::vector& x_samples, const std::vector& y_samples ) { const std::size_t source_row_stride = static_cast(width) * Channels; const std::size_t destination_row_stride = static_cast(new_width) * Channels; for (unsigned y = 0; y < new_height; ++y) { const ResizeAxisSample& y_sample = y_samples[y]; const Byte* const top_row = pixels.data() + static_cast(y_sample.lower) * source_row_stride; const Byte* const bottom_row = pixels.data() + static_cast(y_sample.upper) * source_row_stride; Byte* const destination_row = resized.data() + static_cast(y) * destination_row_stride; for (unsigned x = 0; x < new_width; ++x) { const ResizeAxisSample& x_sample = x_samples[x]; const std::size_t left_offset = static_cast(x_sample.lower) * Channels; const std::size_t right_offset = static_cast(x_sample.upper) * Channels; const float top_left_weight = x_sample.lower_weight * y_sample.lower_weight; const float top_right_weight = x_sample.upper_weight * y_sample.lower_weight; const float bottom_left_weight = x_sample.lower_weight * y_sample.upper_weight; const float bottom_right_weight = x_sample.upper_weight * y_sample.upper_weight; interpolatePixel( destination_row + static_cast(x) * Channels, top_row + left_offset, top_row + right_offset, bottom_row + left_offset, bottom_row + right_offset, top_left_weight, top_right_weight, bottom_left_weight, bottom_right_weight); } } } void decodePreservingColorType( const vBytes& image_file_vec, vBytes& pixels, unsigned& width, unsigned& height, lodepng::State& decode_state) { decode_state.decoder.color_convert = 0; const unsigned error = lodepng::decode(pixels, width, height, decode_state, image_file_vec); image_processing_internal::throwLodepngError("LodePNG decode error", error); } void validateResizeTarget(unsigned new_width, unsigned new_height, unsigned width, unsigned height) { constexpr unsigned MIN_DIMENSION = 68; if (new_width < MIN_DIMENSION || new_height < MIN_DIMENSION) { throw std::runtime_error("Image Error: Resize target dimensions are below the minimum."); } if (new_width > width || new_height > height) { throw std::runtime_error("Image Error: Resize target must not exceed source dimensions."); } } void validateDecodedResizeFormat(bool is_palette, unsigned channels, unsigned bitdepth) { if (channels == 0) { throw std::runtime_error("Image Error: Decoded image reports 0 channels."); } if (!is_palette && bitdepth != 8) { throw std::runtime_error("Image Error: Only 8-bit truecolor/grayscale PNGs are supported."); } if (!is_palette && channels != 3 && channels != 4) { throw std::runtime_error("Image Error: Resize only supports RGB/RGBA truecolor PNGs."); } } void redecodeSubBytePalette( const vBytes& image_file_vec, const lodepng::State& decode_state, vBytes& pixels, unsigned& width, unsigned& height) { lodepng::State redecode_state; redecode_state.decoder.color_convert = 1; redecode_state.info_raw.colortype = LCT_PALETTE; redecode_state.info_raw.bitdepth = 8; // Copy the palette into info_raw so lodepng can convert. const auto& src_color = decode_state.info_png.color; image_processing_internal::copyPalette(src_color.palette, src_color.palettesize, redecode_state.info_raw); pixels.clear(); const unsigned error = lodepng::decode(pixels, width, height, redecode_state, image_file_vec); image_processing_internal::throwLodepngError("LodePNG re-decode error", error); } [[nodiscard]] std::size_t bytesPerPixel(bool is_palette, unsigned channels) { return is_palette ? 1 : channels; } void validateSourceBufferSize(const vBytes& pixels, unsigned width, unsigned height, std::size_t bytes_per_pixel) { const std::size_t source_pixel_count = checkedMultiply( static_cast(width), static_cast(height), "Image Error: Source image dimensions overflow."); const std::size_t source_byte_count = checkedMultiply( source_pixel_count, bytes_per_pixel, "Image Error: Source image buffer size overflow."); if (pixels.size() < source_byte_count) { throw std::runtime_error("Image Error: Decoded image buffer is truncated."); } } [[nodiscard]] vBytes makeResizedPixelBuffer(unsigned new_width, unsigned new_height, std::size_t bytes_per_pixel) { const std::size_t resized_pixel_count = checkedMultiply( static_cast(new_width), static_cast(new_height), "Image Error: Resized image dimensions overflow."); return vBytes(checkedMultiply( resized_pixel_count, bytes_per_pixel, "Image Error: Resized image buffer size overflow.")); } void resizePixels( vBytes& resized, const vBytes& pixels, unsigned width, unsigned new_width, unsigned new_height, bool is_palette, unsigned channels, const std::vector& x_samples, const std::vector& y_samples) { if (is_palette) { resizePaletteImage(resized, pixels, width, new_width, new_height, x_samples, y_samples); } else if (channels == 4) { resizeTruecolorImage<4>(resized, pixels, width, new_width, new_height, x_samples, y_samples); } else { resizeTruecolorImage<3>(resized, pixels, width, new_width, new_height, x_samples, y_samples); } } [[nodiscard]] lodepng::State makeEncodeState( const LodePNGColorMode& png_color, bool is_palette, unsigned decoded_bitdepth) { lodepng::State encode_state; // For sub-byte palettes we decoded to 8-bit, so encode as 8-bit palette. const unsigned encode_bitdepth = (is_palette && decoded_bitdepth < 8) ? 8 : png_color.bitdepth; encode_state.info_raw.colortype = png_color.colortype; encode_state.info_raw.bitdepth = encode_bitdepth; encode_state.info_png.color.colortype = png_color.colortype; encode_state.info_png.color.bitdepth = encode_bitdepth; encode_state.encoder.auto_convert = 0; if (is_palette) { image_processing_internal::copyPalette(png_color.palette, png_color.palettesize, encode_state.info_png.color); image_processing_internal::copyPalette(png_color.palette, png_color.palettesize, encode_state.info_raw); } return encode_state; } } // namespace namespace image_processing_internal { void resizeImage(vBytes& image_file_vec, unsigned new_width, unsigned new_height) { lodepng::State decode_state; vBytes pixels; unsigned width = 0; unsigned height = 0; decodePreservingColorType(image_file_vec, pixels, width, height, decode_state); validateResizeTarget(new_width, new_height, width, height); if (new_width == width && new_height == height) { // Nothing to resample — keep the current encoding untouched. return; } const auto& raw = decode_state.info_raw; const unsigned channels = lodepng_get_channels(&raw); const unsigned bitdepth = raw.bitdepth; const bool is_palette = (raw.colortype == LCT_PALETTE); validateDecodedResizeFormat(is_palette, channels, bitdepth); // Sub-byte palette images need conversion to 8-bit palette first; bilinear // interpolation on packed palette indices would add disproportionate complexity. if (is_palette && bitdepth < 8) { redecodeSubBytePalette(image_file_vec, decode_state, pixels, width, height); // From here on, treat as 8-bit palette (1 byte per pixel index). } const std::vector x_samples = buildResizeAxisSamples(width, new_width); const std::vector y_samples = buildResizeAxisSamples(height, new_height); // Palette images use 1 byte per pixel index; truecolor uses `channels`. const std::size_t pixel_size = bytesPerPixel(is_palette, channels); validateSourceBufferSize(pixels, width, height, pixel_size); vBytes resized = makeResizedPixelBuffer(new_width, new_height, pixel_size); resizePixels(resized, pixels, width, new_width, new_height, is_palette, channels, x_samples, y_samples); // Re-encode with the same color type and palette. const auto& png_color = decode_state.info_png.color; lodepng::State encode_state = makeEncodeState(png_color, is_palette, bitdepth); vBytes output; unsigned error = lodepng::encode(output, resized, new_width, new_height, encode_state); throwLodepngError("LodePNG encode error", error); image_file_vec = std::move(output); } } // namespace image_processing_internal ================================================ FILE: src/lodepng/LICENSE ================================================ Copyright (c) 2005-2018 Lode Vandevenne This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution. ================================================ FILE: src/lodepng/lodepng.cpp ================================================ /* LodePNG version 20260119 Copyright (c) 2005-2026 Lode Vandevenne This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution. */ /* The manual and changelog are in the header file "lodepng.h" Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C. */ #include "lodepng.h" #ifdef LODEPNG_COMPILE_DISK #include /* LONG_MAX */ #include /* file handling */ #endif /* LODEPNG_COMPILE_DISK */ #ifdef LODEPNG_COMPILE_ALLOCATORS #include /* allocations */ #endif /* LODEPNG_COMPILE_ALLOCATORS */ /* pdvzip: use SSE2 for a few encoder byte-comparison and byte-sum hot paths. */ #if defined(__SSE2__) || defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 2) #include #define LODEPNG_PDVZIP_SSE2 1 #else #define LODEPNG_PDVZIP_SSE2 0 #endif #if defined(_MSC_VER) && (_MSC_VER >= 1310) /*Visual Studio: A few warning types are not desired here.*/ #pragma warning( disable : 4244 ) /*implicit conversions: not warned by gcc -Wall -Wextra and requires too much casts*/ #pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/ #endif /*_MSC_VER */ const char* LODEPNG_VERSION_STRING = "20260119"; /* This source file is divided into the following large parts. The code sections with the "LODEPNG_COMPILE_" #defines divide this up further in an intermixed way. -Tools for C and common code for PNG and Zlib -C Code for Zlib (huffman, deflate, ...) -C Code for PNG (file format chunks, adam7, PNG filters, color conversions, ...) -The C++ wrapper around all of the above */ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ /* // Tools for C, and common code for PNG and Zlib. // */ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ /*The malloc, realloc and free functions defined here with "lodepng_" in front of the name, so that you can easily change them to others related to your platform if needed. Everything else in the code calls these. Pass -DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out #define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and define them in your own project's source files without needing to change lodepng source code. Don't forget to remove "static" if you copypaste them from here.*/ #ifdef LODEPNG_COMPILE_ALLOCATORS static void* lodepng_malloc(size_t size) { #ifdef LODEPNG_MAX_ALLOC if(size > LODEPNG_MAX_ALLOC) return 0; #endif return malloc(size); } /* NOTE: when realloc returns NULL, it leaves the original memory untouched */ static void* lodepng_realloc(void* ptr, size_t new_size) { #ifdef LODEPNG_MAX_ALLOC if(new_size > LODEPNG_MAX_ALLOC) return 0; #endif return realloc(ptr, new_size); } static void lodepng_free(void* ptr) { free(ptr); } #else /*LODEPNG_COMPILE_ALLOCATORS*/ /* TODO: support giving additional void* payload to the custom allocators */ void* lodepng_malloc(size_t size); void* lodepng_realloc(void* ptr, size_t new_size); void lodepng_free(void* ptr); #endif /*LODEPNG_COMPILE_ALLOCATORS*/ /* convince the compiler to inline a function, for use when this measurably improves performance */ /* inline is not available in C90, but use it when supported by the compiler */ #if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || (defined(__cplusplus) && (__cplusplus >= 199711L)) #define LODEPNG_INLINE inline #else #define LODEPNG_INLINE /* not available */ #endif /* restrict is not available in C90, but use it when supported by the compiler */ #if (defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))) ||\ (defined(_MSC_VER) && (_MSC_VER >= 1400)) || \ (defined(__WATCOMC__) && (__WATCOMC__ >= 1250) && !defined(__cplusplus)) #define LODEPNG_RESTRICT __restrict #else #define LODEPNG_RESTRICT /* not available */ #endif /* Replacements for C library functions such as memcpy and strlen, to support platforms where a full C library is not available. The compiler can recognize them and compile to something as fast. */ static void lodepng_memcpy(void* LODEPNG_RESTRICT dst, const void* LODEPNG_RESTRICT src, size_t size) { size_t i; for(i = 0; i < size; i++) ((char*)dst)[i] = ((const char*)src)[i]; } static void lodepng_memset(void* LODEPNG_RESTRICT dst, int value, size_t num) { size_t i; for(i = 0; i < num; i++) ((char*)dst)[i] = (char)value; } /* does not check memory out of bounds, do not use on untrusted data */ static size_t lodepng_strlen(const char* a) { const char* orig = a; /* avoid warning about unused function in case of disabled COMPILE... macros */ (void)(&lodepng_strlen); while(*a) a++; return (size_t)(a - orig); } #define LODEPNG_MAX(a, b) (((a) > (b)) ? (a) : (b)) #define LODEPNG_MIN(a, b) (((a) < (b)) ? (a) : (b)) #if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER) /* Safely check if adding two integers will overflow (no undefined behavior, compiler removing the code, etc...) and output result. */ static int lodepng_addofl(size_t a, size_t b, size_t* result) { *result = a + b; /* Unsigned addition is well defined and safe in C90 */ return *result < a; } #endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER)*/ #ifdef LODEPNG_COMPILE_DECODER /* Safely check if multiplying two integers will overflow (no undefined behavior, compiler removing the code, etc...) and output result. */ static int lodepng_mulofl(size_t a, size_t b, size_t* result) { *result = a * b; /* Unsigned multiplication is well defined and safe in C90 */ return (a != 0 && *result / a != b); } #ifdef LODEPNG_COMPILE_ZLIB /* Safely check if a + b > c, even if overflow could happen. */ static int lodepng_gtofl(size_t a, size_t b, size_t c) { size_t d; if(lodepng_addofl(a, b, &d)) return 1; return d > c; } #endif /*LODEPNG_COMPILE_ZLIB*/ #endif /*LODEPNG_COMPILE_DECODER*/ /* Often in case of an error a value is assigned to a variable and then it breaks out of a loop (to go to the cleanup phase of a function). This macro does that. It makes the error handling code shorter and more readable. Example: if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83); */ #define CERROR_BREAK(errorvar, code){\ errorvar = code;\ break;\ } /*version of CERROR_BREAK that assumes the common case where the error variable is named "error"*/ #define ERROR_BREAK(code) CERROR_BREAK(error, code) /*Set error var to the error code, and return it.*/ #define CERROR_RETURN_ERROR(errorvar, code){\ errorvar = code;\ return code;\ } /*Try the code, if it returns error, also return the error.*/ #define CERROR_TRY_RETURN(call){\ unsigned error_ = call;\ if(error_) return error_;\ } /*Set error var to the error code, and return from the void function.*/ #define CERROR_RETURN(errorvar, code){\ errorvar = code;\ return;\ } /* About uivector, ucvector and string: -All of them wrap dynamic arrays or text strings in a similar way. -LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version. -The string tools are made to avoid problems with compilers that declare things like strncat as deprecated. -They're not used in the interface, only internally in this file as static functions. -As with many other structs in this file, the init and cleanup functions serve as ctor and dtor. */ #ifdef LODEPNG_COMPILE_ZLIB #ifdef LODEPNG_COMPILE_ENCODER /*dynamic vector of unsigned ints*/ typedef struct uivector { unsigned* data; size_t size; /*size in number of unsigned longs*/ size_t allocsize; /*allocated size in bytes*/ } uivector; static void uivector_cleanup(void* p) { ((uivector*)p)->size = ((uivector*)p)->allocsize = 0; lodepng_free(((uivector*)p)->data); ((uivector*)p)->data = NULL; } /*returns 1 if success, 0 if failure ==> nothing done*/ static unsigned uivector_resize(uivector* p, size_t size) { size_t allocsize = size * sizeof(unsigned); if(allocsize > p->allocsize) { size_t newsize = allocsize + (p->allocsize >> 1u); void* data = lodepng_realloc(p->data, newsize); if(data) { p->allocsize = newsize; p->data = (unsigned*)data; } else return 0; /*error: not enough memory*/ } p->size = size; return 1; /*success*/ } static void uivector_init(uivector* p) { p->data = NULL; p->size = p->allocsize = 0; } /*returns 1 if success, 0 if failure ==> nothing done*/ static unsigned uivector_push_back(uivector* p, unsigned c) { if(!uivector_resize(p, p->size + 1)) return 0; p->data[p->size - 1] = c; return 1; } #endif /*LODEPNG_COMPILE_ENCODER*/ #endif /*LODEPNG_COMPILE_ZLIB*/ /* /////////////////////////////////////////////////////////////////////////// */ /*dynamic vector of unsigned chars*/ typedef struct ucvector { unsigned char* data; size_t size; /*used size*/ size_t allocsize; /*allocated size*/ } ucvector; /*returns 1 if success, 0 if failure ==> nothing done*/ static unsigned ucvector_reserve(ucvector* p, size_t size) { if(size > p->allocsize) { size_t newsize = size + (p->allocsize >> 1u); void* data = lodepng_realloc(p->data, newsize); if(data) { p->allocsize = newsize; p->data = (unsigned char*)data; } else return 0; /*error: not enough memory*/ } return 1; /*success*/ } /*returns 1 if success, 0 if failure ==> nothing done*/ static unsigned ucvector_resize(ucvector* p, size_t size) { p->size = size; return ucvector_reserve(p, size); } static ucvector ucvector_init(unsigned char* buffer, size_t size) { ucvector v; v.data = buffer; v.allocsize = v.size = size; return v; } /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_PNG #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*also appends null termination character*/ static char* alloc_string_sized(const char* in, size_t insize) { char* out = (char*)lodepng_malloc(insize + 1); if(out) { lodepng_memcpy(out, in, insize); out[insize] = 0; } return out; } /* dynamically allocates a new string with a copy of the null terminated input text */ static char* alloc_string(const char* in) { return alloc_string_sized(in, lodepng_strlen(in)); } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ #endif /*LODEPNG_COMPILE_PNG*/ /* ////////////////////////////////////////////////////////////////////////// */ #if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG) static unsigned lodepng_read32bitInt(const unsigned char* buffer) { return (((unsigned)buffer[0] << 24u) | ((unsigned)buffer[1] << 16u) | ((unsigned)buffer[2] << 8u) | (unsigned)buffer[3]); } #endif /*defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG)*/ #if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER) /*buffer must have at least 4 allocated bytes available*/ static void lodepng_set32bitInt(unsigned char* buffer, unsigned value) { buffer[0] = (unsigned char)((value >> 24) & 0xff); buffer[1] = (unsigned char)((value >> 16) & 0xff); buffer[2] = (unsigned char)((value >> 8) & 0xff); buffer[3] = (unsigned char)((value ) & 0xff); } #endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/ /* ////////////////////////////////////////////////////////////////////////// */ /* / File IO / */ /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_DISK /* returns negative value on error. This should be pure C compatible, so no fstat. */ static long lodepng_filesize(FILE* file) { long size; if(fseek(file, 0, SEEK_END) != 0) return -1; size = ftell(file); /* It may give LONG_MAX as directory size, this is invalid for us. */ if(size == LONG_MAX) return -1; if(fseek(file, 0, SEEK_SET) != 0) return -1; return size; } /* Allocates the output buffer to the file size and reads the file into it. Returns error code.*/ static unsigned lodepng_load_file_(unsigned char** out, size_t* outsize, FILE* file) { long size = lodepng_filesize(file); if(size < 0) return 78; *outsize = (size_t)size; *out = (unsigned char*)lodepng_malloc((size_t)size); if(!(*out) && size > 0) return 83; /*the above malloc failed*/ if(fread(*out, 1, *outsize, file) != *outsize) return 78; return 0; /*ok*/ } unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename) { unsigned error; FILE* file = fopen(filename, "rb"); if(!file) return 78; error = lodepng_load_file_(out, outsize, file); fclose(file); return error; } /*write given buffer to the file, overwriting the file, it doesn't append to it.*/ unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename) { FILE* file = fopen(filename, "wb" ); if(!file) return 79; fwrite(buffer, 1, buffersize, file); fclose(file); return 0; } #endif /*LODEPNG_COMPILE_DISK*/ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ /* // End of common code and tools. Begin of Zlib related code. // */ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_ZLIB #ifdef LODEPNG_COMPILE_ENCODER typedef struct { ucvector* data; unsigned char bp; /*ok to overflow, indicates bit pos inside byte*/ } LodePNGBitWriter; static void LodePNGBitWriter_init(LodePNGBitWriter* writer, ucvector* data) { writer->data = data; writer->bp = 0; } /*TODO: this ignores potential out of memory errors*/ #define WRITEBIT(writer, bit){\ /* append new byte */\ if(((writer->bp) & 7u) == 0) {\ if(!ucvector_resize(writer->data, writer->data->size + 1)) return;\ writer->data->data[writer->data->size - 1] = 0;\ }\ (writer->data->data[writer->data->size - 1]) |= (bit << ((writer->bp) & 7u));\ ++writer->bp;\ } /* LSB of value is written first, and LSB of bytes is used first */ static void writeBits(LodePNGBitWriter* writer, unsigned value, size_t nbits) { if(nbits == 1) { /* compiler should statically compile this case if nbits == 1 */ WRITEBIT(writer, value); } else { /* TODO: increase output size only once here rather than in each WRITEBIT */ size_t i; for(i = 0; i != nbits; ++i) { WRITEBIT(writer, (unsigned char)((value >> i) & 1)); } } } /* This one is to use for adding huffman symbol, the value bits are written MSB first */ static void writeBitsReversed(LodePNGBitWriter* writer, unsigned value, size_t nbits) { size_t i; for(i = 0; i != nbits; ++i) { /* TODO: increase output size only once here rather than in each WRITEBIT */ WRITEBIT(writer, (unsigned char)((value >> (nbits - 1u - i)) & 1u)); } } #endif /*LODEPNG_COMPILE_ENCODER*/ #ifdef LODEPNG_COMPILE_DECODER typedef struct { const unsigned char* data; size_t size; /*size of data in bytes*/ size_t bitsize; /*size of data in bits, end of valid bp values, should be 8*size*/ size_t bp; unsigned buffer; /*buffer for reading bits. NOTE: 'unsigned' must support at least 32 bits*/ } LodePNGBitReader; /* data size argument is in bytes. Returns error if size too large causing overflow */ static unsigned LodePNGBitReader_init(LodePNGBitReader* reader, const unsigned char* data, size_t size) { size_t temp; reader->data = data; reader->size = size; /* size in bits, return error if overflow (if size_t is 32 bit this supports up to 500MB) */ if(lodepng_mulofl(size, 8u, &reader->bitsize)) return 105; /*ensure incremented bp can be compared to bitsize without overflow even when it would be incremented 32 too much and trying to ensure 32 more bits*/ if(lodepng_addofl(reader->bitsize, 64u, &temp)) return 105; reader->bp = 0; reader->buffer = 0; return 0; /*ok*/ } /* ensureBits functions: Ensures the reader can at least read nbits bits in one or more readBits calls, safely even if not enough bits are available. The nbits parameter is unused but is given for documentation purposes, error checking for amount of bits must be done beforehand. */ /*See ensureBits documentation above. This one ensures up to 9 bits */ static LODEPNG_INLINE void ensureBits9(LodePNGBitReader* reader, size_t nbits) { size_t start = reader->bp >> 3u; size_t size = reader->size; if(start + 1u < size) { reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u); reader->buffer >>= (reader->bp & 7u); } else { reader->buffer = 0; if(start + 0u < size) reader->buffer = reader->data[start + 0]; reader->buffer >>= (reader->bp & 7u); } (void)nbits; } /*See ensureBits documentation above. This one ensures up to 17 bits */ static LODEPNG_INLINE void ensureBits17(LodePNGBitReader* reader, size_t nbits) { size_t start = reader->bp >> 3u; size_t size = reader->size; if(start + 2u < size) { reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | ((unsigned)reader->data[start + 2] << 16u); reader->buffer >>= (reader->bp & 7u); } else { reader->buffer = 0; if(start + 0u < size) reader->buffer |= reader->data[start + 0]; if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); reader->buffer >>= (reader->bp & 7u); } (void)nbits; } /*See ensureBits documentation above. This one ensures up to 25 bits */ static LODEPNG_INLINE void ensureBits25(LodePNGBitReader* reader, size_t nbits) { size_t start = reader->bp >> 3u; size_t size = reader->size; if(start + 3u < size) { reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u); reader->buffer >>= (reader->bp & 7u); } else { reader->buffer = 0; if(start + 0u < size) reader->buffer |= reader->data[start + 0]; if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u); reader->buffer >>= (reader->bp & 7u); } (void)nbits; } /*See ensureBits documentation above. This one ensures up to 32 bits */ static LODEPNG_INLINE void ensureBits32(LodePNGBitReader* reader, size_t nbits) { size_t start = reader->bp >> 3u; size_t size = reader->size; if(start + 4u < size) { reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u); reader->buffer >>= (reader->bp & 7u); reader->buffer |= (((unsigned)reader->data[start + 4] << 24u) << (8u - (reader->bp & 7u))); } else { reader->buffer = 0; if(start + 0u < size) reader->buffer |= reader->data[start + 0]; if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u); if(start + 3u < size) reader->buffer |= ((unsigned)reader->data[start + 3] << 24u); reader->buffer >>= (reader->bp & 7u); } (void)nbits; } /* Get bits without advancing the bit pointer. Must have enough bits available with ensureBits. Max nbits is 31. */ static LODEPNG_INLINE unsigned peekBits(LodePNGBitReader* reader, size_t nbits) { /* The shift allows nbits to be only up to 31. */ return reader->buffer & ((1u << nbits) - 1u); } /* Must have enough bits available with ensureBits */ static LODEPNG_INLINE void advanceBits(LodePNGBitReader* reader, size_t nbits) { reader->buffer >>= nbits; reader->bp += nbits; } /* Must have enough bits available with ensureBits */ static LODEPNG_INLINE unsigned readBits(LodePNGBitReader* reader, size_t nbits) { unsigned result = peekBits(reader, nbits); advanceBits(reader, nbits); return result; } #endif /*LODEPNG_COMPILE_DECODER*/ static unsigned reverseBits(unsigned bits, unsigned num) { /*TODO: implement faster lookup table based version when needed*/ unsigned i, result = 0; for(i = 0; i < num; i++) result |= ((bits >> (num - i - 1u)) & 1u) << i; return result; } /* ////////////////////////////////////////////////////////////////////////// */ /* / Deflate - Huffman / */ /* ////////////////////////////////////////////////////////////////////////// */ #define FIRST_LENGTH_CODE_INDEX 257 #define LAST_LENGTH_CODE_INDEX 285 /*256 literals, the end code, some length codes, and 2 unused codes*/ #define NUM_DEFLATE_CODE_SYMBOLS 288 /*the distance codes have their own symbols, 30 used, 2 unused*/ #define NUM_DISTANCE_SYMBOLS 32 /*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/ #define NUM_CODE_LENGTH_CODES 19 /*the base lengths represented by codes 257-285*/ static const unsigned LENGTHBASE[29] = {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258}; /*the extra bits used by codes 257-285 (added to base length)*/ static const unsigned LENGTHEXTRA[29] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0}; /*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/ static const unsigned DISTANCEBASE[30] = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577}; /*the extra bits of backwards distances (added to base)*/ static const unsigned DISTANCEEXTRA[30] = {0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13}; /*the order in which "code length alphabet code lengths" are stored as specified by deflate, out of this the huffman tree of the dynamic huffman tree lengths is generated*/ static const unsigned CLCL_ORDER[NUM_CODE_LENGTH_CODES] = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; /* ////////////////////////////////////////////////////////////////////////// */ /* Huffman tree struct, containing multiple representations of the tree */ typedef struct HuffmanTree { unsigned* codes; /*the huffman codes (bit patterns representing the symbols)*/ unsigned* lengths; /*the lengths of the huffman codes*/ unsigned maxbitlen; /*maximum number of bits a single code can get*/ unsigned numcodes; /*number of symbols in the alphabet = number of codes*/ /* for reading only */ unsigned char* table_len; /*length of symbol from lookup table, or max length if secondary lookup needed*/ unsigned short* table_value; /*value of symbol from lookup table, or pointer to secondary table if needed*/ } HuffmanTree; static void HuffmanTree_init(HuffmanTree* tree) { tree->codes = 0; tree->lengths = 0; tree->table_len = 0; tree->table_value = 0; } static void HuffmanTree_cleanup(HuffmanTree* tree) { lodepng_free(tree->codes); lodepng_free(tree->lengths); lodepng_free(tree->table_len); lodepng_free(tree->table_value); } /* amount of bits for first huffman table lookup (aka root bits), see HuffmanTree_makeTable and huffmanDecodeSymbol.*/ /* values 8u and 9u work the fastest */ #define FIRSTBITS 9u /* a symbol value too big to represent any valid symbol, to indicate reading disallowed huffman bits combination, which is possible in case of only 0 or 1 present symbols. */ #define INVALIDSYMBOL 65535u /* make table for huffman decoding */ static unsigned HuffmanTree_makeTable(HuffmanTree* tree) { static const unsigned headsize = 1u << FIRSTBITS; /*size of the first table*/ static const unsigned mask = (1u << FIRSTBITS) /*headsize*/ - 1u; size_t i, numpresent, pointer, size; /*total table size*/ unsigned* maxlens = (unsigned*)lodepng_malloc(headsize * sizeof(unsigned)); if(!maxlens) return 83; /*alloc fail*/ /* compute maxlens: max total bit length of symbols sharing prefix in the first table*/ lodepng_memset(maxlens, 0, headsize * sizeof(*maxlens)); for(i = 0; i < tree->numcodes; i++) { unsigned symbol = tree->codes[i]; unsigned l = tree->lengths[i]; unsigned index; if(l <= FIRSTBITS) continue; /*symbols that fit in first table don't increase secondary table size*/ /*get the FIRSTBITS MSBs, the MSBs of the symbol are encoded first. See later comment about the reversing*/ index = reverseBits(symbol >> (l - FIRSTBITS), FIRSTBITS); maxlens[index] = LODEPNG_MAX(maxlens[index], l); } /* compute total table size: size of first table plus all secondary tables for symbols longer than FIRSTBITS */ size = headsize; for(i = 0; i < headsize; ++i) { unsigned l = maxlens[i]; if(l > FIRSTBITS) size += (((size_t)1) << (l - FIRSTBITS)); } tree->table_len = (unsigned char*)lodepng_malloc(size * sizeof(*tree->table_len)); tree->table_value = (unsigned short*)lodepng_malloc(size * sizeof(*tree->table_value)); if(!tree->table_len || !tree->table_value) { lodepng_free(maxlens); /* freeing tree->table values is done at a higher scope */ return 83; /*alloc fail*/ } /*initialize with an invalid length to indicate unused entries*/ for(i = 0; i < size; ++i) tree->table_len[i] = 16; /*fill in the first table for long symbols: max prefix size and pointer to secondary tables*/ pointer = headsize; for(i = 0; i < headsize; ++i) { unsigned l = maxlens[i]; if(l <= FIRSTBITS) continue; tree->table_len[i] = l; tree->table_value[i] = (unsigned short)pointer; pointer += (((size_t)1) << (l - FIRSTBITS)); } lodepng_free(maxlens); /*fill in the first table for short symbols, or secondary table for long symbols*/ numpresent = 0; for(i = 0; i < tree->numcodes; ++i) { unsigned l = tree->lengths[i]; unsigned symbol, reverse; if(l == 0) continue; symbol = tree->codes[i]; /*the huffman bit pattern. i itself is the value.*/ /*reverse bits, because the huffman bits are given in MSB first order but the bit reader reads LSB first*/ reverse = reverseBits(symbol, l); numpresent++; if(l <= FIRSTBITS) { /*short symbol, fully in first table, replicated num times if l < FIRSTBITS*/ unsigned num = 1u << (FIRSTBITS - l); unsigned j; for(j = 0; j < num; ++j) { /*bit reader will read the l bits of symbol first, the remaining FIRSTBITS - l bits go to the MSB's*/ unsigned index = reverse | (j << l); if(tree->table_len[index] != 16) return 55; /*invalid tree: long symbol shares prefix with short symbol*/ tree->table_len[index] = l; tree->table_value[index] = (unsigned short)i; } } else { /*long symbol, shares prefix with other long symbols in first lookup table, needs second lookup*/ /*the FIRSTBITS MSBs of the symbol are the first table index*/ unsigned index = reverse & mask; unsigned maxlen = tree->table_len[index]; /*log2 of secondary table length, should be >= l - FIRSTBITS*/ unsigned tablelen = maxlen - FIRSTBITS; unsigned start = tree->table_value[index]; /*starting index in secondary table*/ unsigned num = 1u << (tablelen - (l - FIRSTBITS)); /*amount of entries of this symbol in secondary table*/ unsigned j; if(maxlen < l) return 55; /*invalid tree: long symbol shares prefix with short symbol*/ for(j = 0; j < num; ++j) { unsigned reverse2 = reverse >> FIRSTBITS; /* l - FIRSTBITS bits */ unsigned index2 = start + (reverse2 | (j << (l - FIRSTBITS))); tree->table_len[index2] = l; tree->table_value[index2] = (unsigned short)i; } } } if(numpresent < 2) { /* In case of exactly 1 symbol, in theory the huffman symbol needs 0 bits, but deflate uses 1 bit instead. In case of 0 symbols, no symbols can appear at all, but such huffman tree could still exist (e.g. if distance codes are never used). In both cases, not all symbols of the table will be filled in. Fill them in with an invalid symbol value so returning them from huffmanDecodeSymbol will cause error. */ for(i = 0; i < size; ++i) { if(tree->table_len[i] == 16) { /* As length, use a value smaller than FIRSTBITS for the head table, and a value larger than FIRSTBITS for the secondary table, to ensure valid behavior for advanceBits when reading this symbol. */ tree->table_len[i] = (i < headsize) ? 1 : (FIRSTBITS + 1); tree->table_value[i] = INVALIDSYMBOL; } } } else { /* A good huffman tree has N * 2 - 1 nodes, of which N - 1 are internal nodes. If that is not the case (due to too long length codes), the table will not have been fully used, and this is an error (not all bit combinations can be decoded): an oversubscribed huffman tree, indicated by error 55. */ for(i = 0; i < size; ++i) { if(tree->table_len[i] == 16) return 55; } } return 0; } /* Second step for the ...makeFromLengths and ...makeFromFrequencies functions. numcodes, lengths and maxbitlen must already be filled in correctly. return value is error. */ static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) { unsigned* blcount; unsigned* nextcode; unsigned error = 0; unsigned bits, n; tree->codes = (unsigned*)lodepng_malloc(tree->numcodes * sizeof(unsigned)); blcount = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned)); nextcode = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned)); if(!tree->codes || !blcount || !nextcode) error = 83; /*alloc fail*/ if(!error) { for(n = 0; n != tree->maxbitlen + 1; n++) blcount[n] = nextcode[n] = 0; /*step 1: count number of instances of each code length*/ for(bits = 0; bits != tree->numcodes; ++bits) ++blcount[tree->lengths[bits]]; /*step 2: generate the nextcode values*/ for(bits = 1; bits <= tree->maxbitlen; ++bits) { nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) << 1u; } /*step 3: generate all the codes*/ for(n = 0; n != tree->numcodes; ++n) { if(tree->lengths[n] != 0) { tree->codes[n] = nextcode[tree->lengths[n]]++; /*remove superfluous bits from the code*/ tree->codes[n] &= ((1u << tree->lengths[n]) - 1u); } } } lodepng_free(blcount); lodepng_free(nextcode); if(!error) error = HuffmanTree_makeTable(tree); return error; } /* given the code lengths (as stored in the PNG file), generate the tree as defined by Deflate. maxbitlen is the maximum bits that a code in the tree can have. return value is error. */ static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen, size_t numcodes, unsigned maxbitlen) { unsigned i; tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned)); if(!tree->lengths) return 83; /*alloc fail*/ for(i = 0; i != numcodes; ++i) tree->lengths[i] = bitlen[i]; tree->numcodes = (unsigned)numcodes; /*number of symbols*/ tree->maxbitlen = maxbitlen; return HuffmanTree_makeFromLengths2(tree); } #ifdef LODEPNG_COMPILE_ENCODER /*BPM: Boundary Package Merge, see "A Fast and Space-Economical Algorithm for Length-Limited Coding", Jyrki Katajainen, Alistair Moffat, Andrew Turpin, 1995.*/ /*chain node for boundary package merge*/ typedef struct BPMNode { int weight; /*the sum of all weights in this chain*/ unsigned index; /*index of this leaf node (called "count" in the paper)*/ struct BPMNode* tail; /*the next nodes in this chain (null if last)*/ int in_use; } BPMNode; /*lists of chains*/ typedef struct BPMLists { /*memory pool*/ unsigned memsize; BPMNode* memory; unsigned numfree; unsigned nextfree; BPMNode** freelist; /*two heads of lookahead chains per list*/ unsigned listsize; BPMNode** chains0; BPMNode** chains1; } BPMLists; /*creates a new chain node with the given parameters, from the memory in the lists */ static BPMNode* bpmnode_create(BPMLists* lists, int weight, unsigned index, BPMNode* tail) { unsigned i; BPMNode* result; /*memory full, so garbage collect*/ if(lists->nextfree >= lists->numfree) { /*mark only those that are in use*/ for(i = 0; i != lists->memsize; ++i) lists->memory[i].in_use = 0; for(i = 0; i != lists->listsize; ++i) { BPMNode* node; for(node = lists->chains0[i]; node != 0; node = node->tail) node->in_use = 1; for(node = lists->chains1[i]; node != 0; node = node->tail) node->in_use = 1; } /*collect those that are free*/ lists->numfree = 0; for(i = 0; i != lists->memsize; ++i) { if(!lists->memory[i].in_use) lists->freelist[lists->numfree++] = &lists->memory[i]; } lists->nextfree = 0; } result = lists->freelist[lists->nextfree++]; result->weight = weight; result->index = index; result->tail = tail; return result; } /*sort the leaves with stable mergesort*/ static void bpmnode_sort(BPMNode* leaves, size_t num) { BPMNode* mem = (BPMNode*)lodepng_malloc(sizeof(*leaves) * num); size_t width, counter = 0; for(width = 1; width < num; width *= 2) { BPMNode* a = (counter & 1) ? mem : leaves; BPMNode* b = (counter & 1) ? leaves : mem; size_t p; for(p = 0; p < num; p += 2 * width) { size_t q = (p + width > num) ? num : (p + width); size_t r = (p + 2 * width > num) ? num : (p + 2 * width); size_t i = p, j = q, k; for(k = p; k < r; k++) { if(i < q && (j >= r || a[i].weight <= a[j].weight)) b[k] = a[i++]; else b[k] = a[j++]; } } counter++; } if(counter & 1) lodepng_memcpy(leaves, mem, sizeof(*leaves) * num); lodepng_free(mem); } /*Boundary Package Merge step, numpresent is the amount of leaves, and c is the current chain.*/ static void boundaryPM(BPMLists* lists, BPMNode* leaves, size_t numpresent, int c, int num) { unsigned lastindex = lists->chains1[c]->index; if(c == 0) { if(lastindex >= numpresent) return; lists->chains0[c] = lists->chains1[c]; lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, 0); } else { /*sum of the weights of the head nodes of the previous lookahead chains.*/ int sum = lists->chains0[c - 1]->weight + lists->chains1[c - 1]->weight; lists->chains0[c] = lists->chains1[c]; if(lastindex < numpresent && sum > leaves[lastindex].weight) { lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, lists->chains1[c]->tail); return; } lists->chains1[c] = bpmnode_create(lists, sum, lastindex, lists->chains1[c - 1]); /*in the end we are only interested in the chain of the last list, so no need to recurse if we're at the last one (this gives measurable speedup)*/ if(num + 1 < (int)(2 * numpresent - 2)) { boundaryPM(lists, leaves, numpresent, c - 1, num); boundaryPM(lists, leaves, numpresent, c - 1, num); } } } unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies, size_t numcodes, unsigned maxbitlen) { unsigned error = 0; unsigned i; size_t numpresent = 0; /*number of symbols with non-zero frequency*/ BPMNode* leaves; /*the symbols, only those with > 0 frequency*/ if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/ if((1u << maxbitlen) < (unsigned)numcodes) return 80; /*error: represent all symbols*/ leaves = (BPMNode*)lodepng_malloc(numcodes * sizeof(*leaves)); if(!leaves) return 83; /*alloc fail*/ for(i = 0; i != numcodes; ++i) { if(frequencies[i] > 0) { leaves[numpresent].weight = (int)frequencies[i]; leaves[numpresent].index = i; ++numpresent; } } lodepng_memset(lengths, 0, numcodes * sizeof(*lengths)); /*ensure at least two present symbols. There should be at least one symbol according to RFC 1951 section 3.2.7. Some decoders incorrectly require two. To make these work as well ensure there are at least two symbols. The Package-Merge code below also doesn't work correctly if there's only one symbol, it'd give it the theoretical 0 bits but in practice zlib wants 1 bit*/ if(numpresent == 0) { lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/ } else if(numpresent == 1) { lengths[leaves[0].index] = 1; lengths[leaves[0].index == 0 ? 1 : 0] = 1; } else { BPMLists lists; BPMNode* node; bpmnode_sort(leaves, numpresent); lists.listsize = maxbitlen; lists.memsize = 2 * maxbitlen * (maxbitlen + 1); lists.nextfree = 0; lists.numfree = lists.memsize; lists.memory = (BPMNode*)lodepng_malloc(lists.memsize * sizeof(*lists.memory)); lists.freelist = (BPMNode**)lodepng_malloc(lists.memsize * sizeof(BPMNode*)); lists.chains0 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*)); lists.chains1 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*)); if(!lists.memory || !lists.freelist || !lists.chains0 || !lists.chains1) error = 83; /*alloc fail*/ if(!error) { for(i = 0; i != lists.memsize; ++i) lists.freelist[i] = &lists.memory[i]; bpmnode_create(&lists, leaves[0].weight, 1, 0); bpmnode_create(&lists, leaves[1].weight, 2, 0); for(i = 0; i != lists.listsize; ++i) { lists.chains0[i] = &lists.memory[0]; lists.chains1[i] = &lists.memory[1]; } /*each boundaryPM call adds one chain to the last list, and we need 2 * numpresent - 2 chains.*/ for(i = 2; i != 2 * numpresent - 2; ++i) boundaryPM(&lists, leaves, numpresent, (int)maxbitlen - 1, (int)i); for(node = lists.chains1[maxbitlen - 1]; node; node = node->tail) { for(i = 0; i != node->index; ++i) ++lengths[leaves[i].index]; } } lodepng_free(lists.memory); lodepng_free(lists.freelist); lodepng_free(lists.chains0); lodepng_free(lists.chains1); } lodepng_free(leaves); return error; } /*Create the Huffman tree given the symbol frequencies*/ static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies, size_t mincodes, size_t numcodes, unsigned maxbitlen) { unsigned error = 0; while(!frequencies[numcodes - 1] && numcodes > mincodes) --numcodes; /*trim zeroes*/ tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned)); if(!tree->lengths) return 83; /*alloc fail*/ tree->maxbitlen = maxbitlen; tree->numcodes = (unsigned)numcodes; /*number of symbols*/ error = lodepng_huffman_code_lengths(tree->lengths, frequencies, numcodes, maxbitlen); if(!error) error = HuffmanTree_makeFromLengths2(tree); return error; } #endif /*LODEPNG_COMPILE_ENCODER*/ /*get the literal and length code tree of a deflated block with fixed tree, as per the deflate specification*/ static unsigned generateFixedLitLenTree(HuffmanTree* tree) { unsigned i, error = 0; unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); if(!bitlen) return 83; /*alloc fail*/ /*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/ for(i = 0; i <= 143; ++i) bitlen[i] = 8; for(i = 144; i <= 255; ++i) bitlen[i] = 9; for(i = 256; i <= 279; ++i) bitlen[i] = 7; for(i = 280; i <= 287; ++i) bitlen[i] = 8; error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15); lodepng_free(bitlen); return error; } /*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/ static unsigned generateFixedDistanceTree(HuffmanTree* tree) { unsigned i, error = 0; unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); if(!bitlen) return 83; /*alloc fail*/ /*there are 32 distance codes, but 30-31 are unused*/ for(i = 0; i != NUM_DISTANCE_SYMBOLS; ++i) bitlen[i] = 5; error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15); lodepng_free(bitlen); return error; } #ifdef LODEPNG_COMPILE_DECODER /* returns the code. The bit reader must already have been ensured at least 15 bits */ static unsigned huffmanDecodeSymbol(LodePNGBitReader* reader, const HuffmanTree* codetree) { unsigned short code = peekBits(reader, FIRSTBITS); unsigned short l = codetree->table_len[code]; unsigned short value = codetree->table_value[code]; if(l <= FIRSTBITS) { advanceBits(reader, l); return value; } else { advanceBits(reader, FIRSTBITS); value += peekBits(reader, l - FIRSTBITS); advanceBits(reader, codetree->table_len[value] - FIRSTBITS); return codetree->table_value[value]; } } #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_DECODER /* ////////////////////////////////////////////////////////////////////////// */ /* / Inflator (Decompressor) / */ /* ////////////////////////////////////////////////////////////////////////// */ /*get the tree of a deflated block with fixed tree, as specified in the deflate specification Returns error code.*/ static unsigned getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) { unsigned error = generateFixedLitLenTree(tree_ll); if(error) return error; return generateFixedDistanceTree(tree_d); } /*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/ static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d, LodePNGBitReader* reader) { /*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/ unsigned error = 0; unsigned n, HLIT, HDIST, HCLEN, i; /*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/ unsigned* bitlen_ll = 0; /*lit,len code lengths*/ unsigned* bitlen_d = 0; /*dist code lengths*/ /*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/ unsigned* bitlen_cl = 0; HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/ if(reader->bitsize - reader->bp < 14) return 49; /*error: the bit pointer is or will go past the memory*/ ensureBits17(reader, 14); /*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/ HLIT = readBits(reader, 5) + 257; /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/ HDIST = readBits(reader, 5) + 1; /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/ HCLEN = readBits(reader, 4) + 4; bitlen_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned)); if(!bitlen_cl) return 83 /*alloc fail*/; HuffmanTree_init(&tree_cl); while(!error) { /*read the code length codes out of 3 * (amount of code length codes) bits*/ if(lodepng_gtofl(reader->bp, HCLEN * 3, reader->bitsize)) { ERROR_BREAK(50); /*error: the bit pointer is or will go past the memory*/ } for(i = 0; i != HCLEN; ++i) { ensureBits9(reader, 3); /*out of bounds already checked above */ bitlen_cl[CLCL_ORDER[i]] = readBits(reader, 3); } for(i = HCLEN; i != NUM_CODE_LENGTH_CODES; ++i) { bitlen_cl[CLCL_ORDER[i]] = 0; } error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7); if(error) break; /*now we can use this tree to read the lengths for the tree that this function will return*/ bitlen_ll = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/); lodepng_memset(bitlen_ll, 0, NUM_DEFLATE_CODE_SYMBOLS * sizeof(*bitlen_ll)); lodepng_memset(bitlen_d, 0, NUM_DISTANCE_SYMBOLS * sizeof(*bitlen_d)); /*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/ i = 0; while(i < HLIT + HDIST) { unsigned code; ensureBits25(reader, 22); /* up to 15 bits for huffman code, up to 7 extra bits below*/ code = huffmanDecodeSymbol(reader, &tree_cl); if(code <= 15) /*a length code*/ { if(i < HLIT) bitlen_ll[i] = code; else bitlen_d[i - HLIT] = code; ++i; } else if(code == 16) /*repeat previous*/ { unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/ unsigned value; /*set value to the previous code*/ if(i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/ replength += readBits(reader, 2); if(i < HLIT + 1) value = bitlen_ll[i - 1]; else value = bitlen_d[i - HLIT - 1]; /*repeat this value in the next lengths*/ for(n = 0; n < replength; ++n) { if(i >= HLIT + HDIST) ERROR_BREAK(13); /*error: i is larger than the amount of codes*/ if(i < HLIT) bitlen_ll[i] = value; else bitlen_d[i - HLIT] = value; ++i; } } else if(code == 17) /*repeat "0" 3-10 times*/ { unsigned replength = 3; /*read in the bits that indicate repeat length*/ replength += readBits(reader, 3); /*repeat this value in the next lengths*/ for(n = 0; n < replength; ++n) { if(i >= HLIT + HDIST) ERROR_BREAK(14); /*error: i is larger than the amount of codes*/ if(i < HLIT) bitlen_ll[i] = 0; else bitlen_d[i - HLIT] = 0; ++i; } } else if(code == 18) /*repeat "0" 11-138 times*/ { unsigned replength = 11; /*read in the bits that indicate repeat length*/ replength += readBits(reader, 7); /*repeat this value in the next lengths*/ for(n = 0; n < replength; ++n) { if(i >= HLIT + HDIST) ERROR_BREAK(15); /*error: i is larger than the amount of codes*/ if(i < HLIT) bitlen_ll[i] = 0; else bitlen_d[i - HLIT] = 0; ++i; } } else /*if(code == INVALIDSYMBOL)*/ { ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ } /*check if any of the ensureBits above went out of bounds*/ if(reader->bp > reader->bitsize) { /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol (10=no endcode, 11=wrong jump outside of tree)*/ /* TODO: revise error codes 10,11,50: the above comment is no longer valid */ ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ } } if(error) break; if(bitlen_ll[256] == 0) ERROR_BREAK(64); /*the length of the end code 256 must be larger than 0*/ /*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/ error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15); if(error) break; error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15); break; /*end of error-while*/ } lodepng_free(bitlen_cl); lodepng_free(bitlen_ll); lodepng_free(bitlen_d); HuffmanTree_cleanup(&tree_cl); return error; } /*inflate a block with dynamic of fixed Huffman tree. btype must be 1 or 2.*/ static unsigned inflateHuffmanBlock(ucvector* out, LodePNGBitReader* reader, unsigned btype, size_t max_output_size) { unsigned error = 0; HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/ HuffmanTree tree_d; /*the huffman tree for distance codes*/ const size_t reserved_size = 260; /* must be at least 258 for max length, and a few extra for adding a few extra literals */ int done = 0; if(!ucvector_reserve(out, out->size + reserved_size)) return 83; /*alloc fail*/ HuffmanTree_init(&tree_ll); HuffmanTree_init(&tree_d); if(btype == 1) error = getTreeInflateFixed(&tree_ll, &tree_d); else /*if(btype == 2)*/ error = getTreeInflateDynamic(&tree_ll, &tree_d, reader); while(!error && !done) /*decode all symbols until end reached, breaks at end code*/ { /*code_ll is literal, length or end code*/ unsigned code_ll; /* ensure enough bits for 2 huffman code reads (15 bits each): if the first is a literal, a second literal is read at once. This appears to be slightly faster, than ensuring 20 bits here for 1 huffman symbol and the potential 5 extra bits for the length symbol.*/ ensureBits32(reader, 30); code_ll = huffmanDecodeSymbol(reader, &tree_ll); if(code_ll <= 255) { /*slightly faster code path if multiple literals in a row*/ out->data[out->size++] = (unsigned char)code_ll; code_ll = huffmanDecodeSymbol(reader, &tree_ll); } if(code_ll <= 255) /*literal symbol*/ { out->data[out->size++] = (unsigned char)code_ll; } else if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/ { unsigned code_d, distance; unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/ size_t start, backward, length; /*part 1: get length base*/ length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX]; /*part 2: get extra bits and add the value of that to length*/ numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX]; if(numextrabits_l != 0) { /* bits already ensured above */ ensureBits25(reader, 5); length += readBits(reader, numextrabits_l); } /*part 3: get distance code*/ ensureBits32(reader, 28); /* up to 15 for the huffman symbol, up to 13 for the extra bits */ code_d = huffmanDecodeSymbol(reader, &tree_d); if(code_d > 29) { if(code_d <= 31) { ERROR_BREAK(18); /*error: invalid distance code (30-31 are never used)*/ } else /* if(code_d == INVALIDSYMBOL) */{ ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ } } distance = DISTANCEBASE[code_d]; /*part 4: get extra bits from distance*/ numextrabits_d = DISTANCEEXTRA[code_d]; if(numextrabits_d != 0) { /* bits already ensured above */ distance += readBits(reader, numextrabits_d); } /*part 5: fill in all the out[n] values based on the length and dist*/ start = out->size; if(distance > start) ERROR_BREAK(52); /*too long backward distance*/ backward = start - distance; out->size += length; if(distance < length) { size_t forward; lodepng_memcpy(out->data + start, out->data + backward, distance); start += distance; for(forward = distance; forward < length; ++forward) { out->data[start++] = out->data[backward++]; } } else { lodepng_memcpy(out->data + start, out->data + backward, length); } } else if(code_ll == 256) { done = 1; /*end code, finish the loop*/ } else /*if(code_ll == INVALIDSYMBOL)*/ { ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ } if(out->allocsize - out->size < reserved_size) { if(!ucvector_reserve(out, out->size + reserved_size)) ERROR_BREAK(83); /*alloc fail*/ } /*check if any of the ensureBits above went out of bounds*/ if(reader->bp > reader->bitsize) { /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol (10=no endcode, 11=wrong jump outside of tree)*/ /* TODO: revise error codes 10,11,50: the above comment is no longer valid */ ERROR_BREAK(51); /*error, bit pointer jumps past memory*/ } if(max_output_size && out->size > max_output_size) { ERROR_BREAK(109); /*error, larger than max size*/ } } HuffmanTree_cleanup(&tree_ll); HuffmanTree_cleanup(&tree_d); return error; } static unsigned inflateNoCompression(ucvector* out, LodePNGBitReader* reader, const LodePNGDecompressSettings* settings) { size_t bytepos; size_t size = reader->size; unsigned LEN, NLEN, error = 0; /*go to first boundary of byte*/ bytepos = (reader->bp + 7u) >> 3u; /*read LEN (2 bytes) and NLEN (2 bytes)*/ if(bytepos + 4 >= size) return 52; /*error, bit pointer will jump past memory*/ LEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2; NLEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2; /*check if 16-bit NLEN is really the one's complement of LEN*/ if(!settings->ignore_nlen && LEN + NLEN != 65535) { return 21; /*error: NLEN is not one's complement of LEN*/ } if(!ucvector_resize(out, out->size + LEN)) return 83; /*alloc fail*/ /*read the literal data: LEN bytes are now stored in the out buffer*/ if(bytepos + LEN > size) return 23; /*error: reading outside of in buffer*/ /*out->data can be NULL (when LEN is zero), and arithmetic on NULL ptr is undefined*/ if (LEN) { lodepng_memcpy(out->data + out->size - LEN, reader->data + bytepos, LEN); bytepos += LEN; } reader->bp = bytepos << 3u; return error; } static unsigned lodepng_inflatev(ucvector* out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { unsigned BFINAL = 0; LodePNGBitReader reader; unsigned error = LodePNGBitReader_init(&reader, in, insize); if(error) return error; while(!BFINAL) { unsigned BTYPE; if(reader.bitsize - reader.bp < 3) return 52; /*error, bit pointer will jump past memory*/ ensureBits9(&reader, 3); BFINAL = readBits(&reader, 1); BTYPE = readBits(&reader, 2); if(BTYPE == 3) return 20; /*error: invalid BTYPE*/ else if(BTYPE == 0) error = inflateNoCompression(out, &reader, settings); /*no compression*/ else error = inflateHuffmanBlock(out, &reader, BTYPE, settings->max_output_size); /*compression, BTYPE 01 or 10*/ if(!error && settings->max_output_size && out->size > settings->max_output_size) error = 109; if(error) break; } return error; } unsigned lodepng_inflate(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { ucvector v = ucvector_init(*out, *outsize); unsigned error = lodepng_inflatev(&v, in, insize, settings); *out = v.data; *outsize = v.size; return error; } static unsigned inflatev(ucvector* out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { if(settings->custom_inflate) { unsigned error = settings->custom_inflate(&out->data, &out->size, in, insize, settings); out->allocsize = out->size; if(error) { /*the custom inflate is allowed to have its own error codes, however, we translate it to code 110*/ error = 110; /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/ if(settings->max_output_size && out->size > settings->max_output_size) error = 109; } return error; } else { return lodepng_inflatev(out, in, insize, settings); } } #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER /* ////////////////////////////////////////////////////////////////////////// */ /* / Deflator (Compressor) / */ /* ////////////////////////////////////////////////////////////////////////// */ static const unsigned MAX_SUPPORTED_DEFLATE_LENGTH = 258; /*search the index in the array, that has the largest value smaller than or equal to the given value, given array must be sorted (if no value is smaller, it returns the size of the given array)*/ static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value) { /*binary search (only small gain over linear). TODO: use CPU log2 instruction for getting symbols instead*/ size_t left = 1; size_t right = array_size - 1; while(left <= right) { size_t mid = (left + right) >> 1; if(array[mid] >= value) right = mid - 1; else left = mid + 1; } if(left >= array_size || array[left] > value) left--; return left; } static void addLengthDistance(uivector* values, size_t length, size_t distance) { /*values in encoded vector are those used by deflate: 0-255: literal bytes 256: end 257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits) 286-287: invalid*/ unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length); unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]); unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance); unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]); size_t pos = values->size; /*TODO: return error when this fails (out of memory)*/ unsigned ok = uivector_resize(values, values->size + 4); if(ok) { values->data[pos + 0] = length_code + FIRST_LENGTH_CODE_INDEX; values->data[pos + 1] = extra_length; values->data[pos + 2] = dist_code; values->data[pos + 3] = extra_distance; } } /*3 bytes of data get encoded into two bytes. The hash cannot use more than 3 bytes as input because 3 is the minimum match length for deflate*/ static const unsigned HASH_NUM_VALUES = 65536; static const unsigned HASH_BIT_MASK = 65535; /*HASH_NUM_VALUES - 1, but C90 does not like that as initializer*/ typedef struct Hash { int* head; /*hash value to head circular pos - can be outdated if went around window*/ /*circular pos to prev circular pos*/ unsigned short* chain; int* val; /*circular pos to hash value*/ /*TODO: do this not only for zeros but for any repeated byte. However for PNG it's always going to be the zeros that dominate, so not important for PNG*/ int* headz; /*similar to head, but for chainz*/ unsigned short* chainz; /*those with same amount of zeros*/ unsigned short* zeros; /*length of zeros streak, used as a second hash chain*/ } Hash; static unsigned hash_init(Hash* hash, unsigned windowsize) { unsigned i; hash->head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES); hash->val = (int*)lodepng_malloc(sizeof(int) * windowsize); hash->chain = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); hash->zeros = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); hash->headz = (int*)lodepng_malloc(sizeof(int) * (MAX_SUPPORTED_DEFLATE_LENGTH + 1)); hash->chainz = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); if(!hash->head || !hash->chain || !hash->val || !hash->headz|| !hash->chainz || !hash->zeros) { return 83; /*alloc fail*/ } /*initialize hash table*/ for(i = 0; i != HASH_NUM_VALUES; ++i) hash->head[i] = -1; for(i = 0; i != windowsize; ++i) hash->val[i] = -1; for(i = 0; i != windowsize; ++i) hash->chain[i] = i; /*same value as index indicates uninitialized*/ for(i = 0; i <= MAX_SUPPORTED_DEFLATE_LENGTH; ++i) hash->headz[i] = -1; for(i = 0; i != windowsize; ++i) hash->chainz[i] = i; /*same value as index indicates uninitialized*/ return 0; } static void hash_cleanup(Hash* hash) { lodepng_free(hash->head); lodepng_free(hash->val); lodepng_free(hash->chain); lodepng_free(hash->zeros); lodepng_free(hash->headz); lodepng_free(hash->chainz); } static unsigned getHash(const unsigned char* data, size_t size, size_t pos) { unsigned result = 0; if(pos + 2 < size) { /*A simple shift and xor hash is used. Since the data of PNGs is dominated by zeroes due to the filters, a better hash does not have a significant effect on speed in traversing the chain, and causes more time spend on calculating the hash.*/ result ^= ((unsigned)data[pos + 0] << 0u); result ^= ((unsigned)data[pos + 1] << 4u); result ^= ((unsigned)data[pos + 2] << 8u); } else { size_t amount, i; if(pos >= size) return 0; amount = size - pos; for(i = 0; i != amount; ++i) result ^= ((unsigned)data[pos + i] << (i * 8u)); } return result & HASH_BIT_MASK; } #if LODEPNG_PDVZIP_SSE2 static unsigned countLowOneBits16(unsigned mask) { unsigned count = 0; while(mask & 1u) { ++count; mask >>= 1u; } return count; } #endif static unsigned countZeros(const unsigned char* data, size_t size, size_t pos) { const unsigned char* start = data + pos; const unsigned char* end = start + MAX_SUPPORTED_DEFLATE_LENGTH; if(end > data + size) end = data + size; data = start; #if LODEPNG_PDVZIP_SSE2 { const __m128i zero = _mm_setzero_si128(); while((size_t)(end - data) >= 16) { const __m128i bytes = _mm_loadu_si128((const __m128i*)data); const unsigned mask = (unsigned)_mm_movemask_epi8(_mm_cmpeq_epi8(bytes, zero)); if(mask != 0xffffu) { return (unsigned)(data - start) + countLowOneBits16(mask); } data += 16; } } #endif while(data != end && *data == 0) ++data; /*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/ return (unsigned)(data - start); } static unsigned countMatchingBytes(const unsigned char* foreptr, const unsigned char* backptr, const unsigned char* lastptr) { const unsigned char* start = foreptr; #if LODEPNG_PDVZIP_SSE2 while((size_t)(lastptr - foreptr) >= 16) { const __m128i front = _mm_loadu_si128((const __m128i*)foreptr); const __m128i back = _mm_loadu_si128((const __m128i*)backptr); const unsigned mask = (unsigned)_mm_movemask_epi8(_mm_cmpeq_epi8(front, back)); if(mask != 0xffffu) { return (unsigned)(foreptr - start) + countLowOneBits16(mask); } foreptr += 16; backptr += 16; } #endif while(foreptr != lastptr && *backptr == *foreptr) { ++backptr; ++foreptr; } return (unsigned)(foreptr - start); } /*wpos = pos & (windowsize - 1)*/ static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, unsigned short numzeros) { hash->val[wpos] = (int)hashval; if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval]; hash->head[hashval] = (int)wpos; hash->zeros[wpos] = numzeros; if(hash->headz[numzeros] != -1) hash->chainz[wpos] = hash->headz[numzeros]; hash->headz[numzeros] = (int)wpos; } /* LZ77-encode the data. Return value is error code. The input are raw bytes, the output is in the form of unsigned integers with codes representing for example literal bytes, or length/distance pairs. It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a sliding window (of windowsize) is used, and all past bytes in that window can be used as the "dictionary". A brute force search through all possible distances would be slow, and this hash technique is one out of several ways to speed this up. */ static unsigned encodeLZ77(uivector* out, Hash* hash, const unsigned char* in, size_t inpos, size_t insize, unsigned windowsize, unsigned minmatch, unsigned nicematch, unsigned lazymatching) { size_t pos; unsigned i, error = 0; /*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/ unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8u; unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64; unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/ unsigned numzeros = 0; unsigned offset; /*the offset represents the distance in LZ77 terminology*/ unsigned length; unsigned lazy = 0; unsigned lazylength = 0, lazyoffset = 0; unsigned hashval; unsigned current_offset, current_length; unsigned prev_offset; const unsigned char *lastptr, *foreptr, *backptr; unsigned hashpos; if(windowsize == 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/ if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/ if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH; for(pos = inpos; pos < insize; ++pos) { size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/ unsigned chainlength = 0; hashval = getHash(in, insize, pos); if(usezeros && hashval == 0) { if(numzeros == 0) numzeros = countZeros(in, insize, pos); else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros; } else { numzeros = 0; } updateHashChain(hash, wpos, hashval, numzeros); /*the length and offset found for the current position*/ length = 0; offset = 0; hashpos = hash->chain[wpos]; lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH]; /*search for the longest string*/ prev_offset = 0; for(;;) { if(chainlength++ >= maxchainlength) break; current_offset = (unsigned)(hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize); if(current_offset < prev_offset) break; /*stop when went completely around the circular buffer*/ prev_offset = current_offset; if(current_offset > 0) { /*test the next characters*/ foreptr = &in[pos]; backptr = &in[pos - current_offset]; /*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/ if(numzeros >= 3) { unsigned skip = hash->zeros[hashpos]; if(skip > numzeros) skip = numzeros; backptr += skip; foreptr += skip; } foreptr += countMatchingBytes(foreptr, backptr, lastptr); current_length = (unsigned)(foreptr - &in[pos]); if(current_length > length) { length = current_length; /*the longest length*/ offset = current_offset; /*the offset that is related to this longest length*/ /*jump out once a length of max length is found (speed gain). This also jumps out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/ if(current_length >= nicematch) break; } } if(hashpos == hash->chain[hashpos]) break; if(numzeros >= 3 && length > numzeros) { hashpos = hash->chainz[hashpos]; if(hash->zeros[hashpos] != numzeros) break; } else { hashpos = hash->chain[hashpos]; /*outdated hash value, happens if particular value was not encountered in whole last window*/ if(hash->val[hashpos] != (int)hashval) break; } } if(lazymatching) { if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH) { lazy = 1; lazylength = length; lazyoffset = offset; continue; /*try the next byte*/ } if(lazy) { lazy = 0; if(pos == 0) ERROR_BREAK(81); if(length > lazylength + 1) { /*push the previous character as literal*/ if(!uivector_push_back(out, in[pos - 1])) ERROR_BREAK(83 /*alloc fail*/); } else { length = lazylength; offset = lazyoffset; hash->head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/ hash->headz[numzeros] = -1; /*idem*/ --pos; } } } if(length >= 3 && offset > windowsize) ERROR_BREAK(86 /*too big (or overflown negative) offset*/); /*encode it as length/distance pair or literal value*/ if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/ { if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); } else if(length < minmatch || (length == 3 && offset > 4096)) { /*compensate for the fact that longer offsets have more extra bits, a length of only 3 may be not worth it then*/ if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); } else { addLengthDistance(out, length, offset); for(i = 1; i < length; ++i) { ++pos; wpos = pos & (windowsize - 1); hashval = getHash(in, insize, pos); if(usezeros && hashval == 0) { if(numzeros == 0) numzeros = countZeros(in, insize, pos); else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros; } else { numzeros = 0; } updateHashChain(hash, wpos, hashval, numzeros); } } } /*end of the loop through each character of input*/ return error; } /* /////////////////////////////////////////////////////////////////////////// */ static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize) { /*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte, 2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/ size_t i, numdeflateblocks = (datasize + 65534u) / 65535u; size_t datapos = 0; for(i = 0; i != numdeflateblocks; ++i) { unsigned BFINAL, BTYPE, LEN, NLEN; unsigned char firstbyte; size_t pos = out->size; BFINAL = (i == numdeflateblocks - 1); BTYPE = 0; LEN = 65535; if(datasize - datapos < 65535u) LEN = (unsigned)datasize - (unsigned)datapos; NLEN = 65535 - LEN; if(!ucvector_resize(out, out->size + LEN + 5)) return 83; /*alloc fail*/ firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1u) << 1u) + ((BTYPE & 2u) << 1u)); out->data[pos + 0] = firstbyte; out->data[pos + 1] = (unsigned char)(LEN & 255); out->data[pos + 2] = (unsigned char)(LEN >> 8u); out->data[pos + 3] = (unsigned char)(NLEN & 255); out->data[pos + 4] = (unsigned char)(NLEN >> 8u); lodepng_memcpy(out->data + pos + 5, data + datapos, LEN); datapos += LEN; } return 0; } /* write the lz77-encoded data, which has lit, len and dist codes, to compressed stream using huffman trees. tree_ll: the tree for lit and len codes. tree_d: the tree for distance codes. */ static void writeLZ77data(LodePNGBitWriter* writer, const uivector* lz77_encoded, const HuffmanTree* tree_ll, const HuffmanTree* tree_d) { size_t i = 0; for(i = 0; i != lz77_encoded->size; ++i) { unsigned val = lz77_encoded->data[i]; writeBitsReversed(writer, tree_ll->codes[val], tree_ll->lengths[val]); if(val > 256) /*for a length code, 3 more things have to be added*/ { unsigned length_index = val - FIRST_LENGTH_CODE_INDEX; unsigned n_length_extra_bits = LENGTHEXTRA[length_index]; unsigned length_extra_bits = lz77_encoded->data[++i]; unsigned distance_code = lz77_encoded->data[++i]; unsigned distance_index = distance_code; unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index]; unsigned distance_extra_bits = lz77_encoded->data[++i]; writeBits(writer, length_extra_bits, n_length_extra_bits); writeBitsReversed(writer, tree_d->codes[distance_code], tree_d->lengths[distance_code]); writeBits(writer, distance_extra_bits, n_distance_extra_bits); } } } /*Deflate for a block of type "dynamic", that is, with freely, optimally, created huffman trees*/ static unsigned deflateDynamic(LodePNGBitWriter* writer, Hash* hash, const unsigned char* data, size_t datapos, size_t dataend, const LodePNGCompressSettings* settings, unsigned final) { unsigned error = 0; /* A block is compressed as follows: The PNG data is lz77 encoded, resulting in literal bytes and length/distance pairs. This is then huffman compressed with two huffman trees. One huffman tree is used for the lit and len values ("ll"), another huffman tree is used for the dist values ("d"). These two trees are stored using their code lengths, and to compress even more these code lengths are also run-length encoded and huffman compressed. This gives a huffman tree of code lengths "cl". The code lengths used to describe this third tree are the code length code lengths ("clcl"). */ /*The lz77 encoded data, represented with integers since there will also be length and distance codes in it*/ uivector lz77_encoded; HuffmanTree tree_ll; /*tree for lit,len values*/ HuffmanTree tree_d; /*tree for distance codes*/ HuffmanTree tree_cl; /*tree for encoding the code lengths representing tree_ll and tree_d*/ unsigned* frequencies_ll = 0; /*frequency of lit,len codes*/ unsigned* frequencies_d = 0; /*frequency of dist codes*/ unsigned* frequencies_cl = 0; /*frequency of code length codes*/ unsigned* bitlen_lld = 0; /*lit,len,dist code lengths (int bits), literally (without repeat codes).*/ unsigned* bitlen_lld_e = 0; /*bitlen_lld encoded with repeat codes (this is a rudimentary run length compression)*/ size_t datasize = dataend - datapos; /* If we could call "bitlen_cl" the the code length code lengths ("clcl"), that is the bit lengths of codes to represent tree_cl in CLCL_ORDER, then due to the huffman compression of huffman tree representations ("two levels"), there are some analogies: bitlen_lld is to tree_cl what data is to tree_ll and tree_d. bitlen_lld_e is to bitlen_lld what lz77_encoded is to data. bitlen_cl is to bitlen_lld_e what bitlen_lld is to lz77_encoded. */ unsigned BFINAL = final; size_t i; size_t numcodes_ll, numcodes_d, numcodes_lld, numcodes_lld_e, numcodes_cl; unsigned HLIT, HDIST, HCLEN; uivector_init(&lz77_encoded); HuffmanTree_init(&tree_ll); HuffmanTree_init(&tree_d); HuffmanTree_init(&tree_cl); /* could fit on stack, but >1KB is on the larger side so allocate instead */ frequencies_ll = (unsigned*)lodepng_malloc(286 * sizeof(*frequencies_ll)); frequencies_d = (unsigned*)lodepng_malloc(30 * sizeof(*frequencies_d)); frequencies_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl)); if(!frequencies_ll || !frequencies_d || !frequencies_cl) error = 83; /*alloc fail*/ /*This while loop never loops due to a break at the end, it is here to allow breaking out of it to the cleanup phase on error conditions.*/ while(!error) { lodepng_memset(frequencies_ll, 0, 286 * sizeof(*frequencies_ll)); lodepng_memset(frequencies_d, 0, 30 * sizeof(*frequencies_d)); lodepng_memset(frequencies_cl, 0, NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl)); if(settings->use_lz77) { error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize, settings->minmatch, settings->nicematch, settings->lazymatching); if(error) break; } else { if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83 /*alloc fail*/); for(i = datapos; i < dataend; ++i) lz77_encoded.data[i - datapos] = data[i]; /*no LZ77, but still will be Huffman compressed*/ } /*Count the frequencies of lit, len and dist codes*/ for(i = 0; i != lz77_encoded.size; ++i) { unsigned symbol = lz77_encoded.data[i]; ++frequencies_ll[symbol]; if(symbol > 256) { unsigned dist = lz77_encoded.data[i + 2]; ++frequencies_d[dist]; i += 3; } } frequencies_ll[256] = 1; /*there will be exactly 1 end code, at the end of the block*/ /*Make both huffman trees, one for the lit and len codes, one for the dist codes*/ error = HuffmanTree_makeFromFrequencies(&tree_ll, frequencies_ll, 257, 286, 15); if(error) break; /*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/ error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d, 2, 30, 15); if(error) break; numcodes_ll = LODEPNG_MIN(tree_ll.numcodes, 286); numcodes_d = LODEPNG_MIN(tree_d.numcodes, 30); /*store the code lengths of both generated trees in bitlen_lld*/ numcodes_lld = numcodes_ll + numcodes_d; bitlen_lld = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld)); /*numcodes_lld_e never needs more size than bitlen_lld*/ bitlen_lld_e = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld_e)); if(!bitlen_lld || !bitlen_lld_e) ERROR_BREAK(83); /*alloc fail*/ numcodes_lld_e = 0; for(i = 0; i != numcodes_ll; ++i) bitlen_lld[i] = tree_ll.lengths[i]; for(i = 0; i != numcodes_d; ++i) bitlen_lld[numcodes_ll + i] = tree_d.lengths[i]; /*run-length compress bitlen_ldd into bitlen_lld_e by using repeat codes 16 (copy length 3-6 times), 17 (3-10 zeroes), 18 (11-138 zeroes)*/ for(i = 0; i != numcodes_lld; ++i) { unsigned j = 0; /*amount of repetitions*/ while(i + j + 1 < numcodes_lld && bitlen_lld[i + j + 1] == bitlen_lld[i]) ++j; if(bitlen_lld[i] == 0 && j >= 2) /*repeat code for zeroes*/ { ++j; /*include the first zero*/ if(j <= 10) /*repeat code 17 supports max 10 zeroes*/ { bitlen_lld_e[numcodes_lld_e++] = 17; bitlen_lld_e[numcodes_lld_e++] = j - 3; } else /*repeat code 18 supports max 138 zeroes*/ { if(j > 138) j = 138; bitlen_lld_e[numcodes_lld_e++] = 18; bitlen_lld_e[numcodes_lld_e++] = j - 11; } i += (j - 1); } else if(j >= 3) /*repeat code for value other than zero*/ { size_t k; unsigned num = j / 6u, rest = j % 6u; bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i]; for(k = 0; k < num; ++k) { bitlen_lld_e[numcodes_lld_e++] = 16; bitlen_lld_e[numcodes_lld_e++] = 6 - 3; } if(rest >= 3) { bitlen_lld_e[numcodes_lld_e++] = 16; bitlen_lld_e[numcodes_lld_e++] = rest - 3; } else j -= rest; i += j; } else /*too short to benefit from repeat code*/ { bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i]; } } /*generate tree_cl, the huffmantree of huffmantrees*/ for(i = 0; i != numcodes_lld_e; ++i) { ++frequencies_cl[bitlen_lld_e[i]]; /*after a repeat code come the bits that specify the number of repetitions, those don't need to be in the frequencies_cl calculation*/ if(bitlen_lld_e[i] >= 16) ++i; } error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl, NUM_CODE_LENGTH_CODES, NUM_CODE_LENGTH_CODES, 7); if(error) break; /*compute amount of code-length-code-lengths to output*/ numcodes_cl = NUM_CODE_LENGTH_CODES; /*trim zeros at the end (using CLCL_ORDER), but minimum size must be 4 (see HCLEN below)*/ while(numcodes_cl > 4u && tree_cl.lengths[CLCL_ORDER[numcodes_cl - 1u]] == 0) { numcodes_cl--; } /* Write everything into the output After the BFINAL and BTYPE, the dynamic block consists out of the following: - 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN - (HCLEN+4)*3 bits code lengths of code length alphabet - HLIT + 257 code lengths of lit/length alphabet (encoded using the code length alphabet, + possible repetition codes 16, 17, 18) - HDIST + 1 code lengths of distance alphabet (encoded using the code length alphabet, + possible repetition codes 16, 17, 18) - compressed data - 256 (end code) */ /*Write block type*/ writeBits(writer, BFINAL, 1); writeBits(writer, 0, 1); /*first bit of BTYPE "dynamic"*/ writeBits(writer, 1, 1); /*second bit of BTYPE "dynamic"*/ /*write the HLIT, HDIST and HCLEN values*/ /*all three sizes take trimmed ending zeroes into account, done either by HuffmanTree_makeFromFrequencies or in the loop for numcodes_cl above, which saves space. */ HLIT = (unsigned)(numcodes_ll - 257); HDIST = (unsigned)(numcodes_d - 1); HCLEN = (unsigned)(numcodes_cl - 4); writeBits(writer, HLIT, 5); writeBits(writer, HDIST, 5); writeBits(writer, HCLEN, 4); /*write the code lengths of the code length alphabet ("bitlen_cl")*/ for(i = 0; i != numcodes_cl; ++i) writeBits(writer, tree_cl.lengths[CLCL_ORDER[i]], 3); /*write the lengths of the lit/len AND the dist alphabet*/ for(i = 0; i != numcodes_lld_e; ++i) { writeBitsReversed(writer, tree_cl.codes[bitlen_lld_e[i]], tree_cl.lengths[bitlen_lld_e[i]]); /*extra bits of repeat codes*/ if(bitlen_lld_e[i] == 16) writeBits(writer, bitlen_lld_e[++i], 2); else if(bitlen_lld_e[i] == 17) writeBits(writer, bitlen_lld_e[++i], 3); else if(bitlen_lld_e[i] == 18) writeBits(writer, bitlen_lld_e[++i], 7); } /*write the compressed data symbols*/ writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d); /*error: the length of the end code 256 must be larger than 0*/ if(tree_ll.lengths[256] == 0) ERROR_BREAK(64); /*write the end code*/ writeBitsReversed(writer, tree_ll.codes[256], tree_ll.lengths[256]); break; /*end of error-while*/ } /*cleanup*/ uivector_cleanup(&lz77_encoded); HuffmanTree_cleanup(&tree_ll); HuffmanTree_cleanup(&tree_d); HuffmanTree_cleanup(&tree_cl); lodepng_free(frequencies_ll); lodepng_free(frequencies_d); lodepng_free(frequencies_cl); lodepng_free(bitlen_lld); lodepng_free(bitlen_lld_e); return error; } static unsigned deflateFixed(LodePNGBitWriter* writer, Hash* hash, const unsigned char* data, size_t datapos, size_t dataend, const LodePNGCompressSettings* settings, unsigned final) { HuffmanTree tree_ll; /*tree for literal values and length codes*/ HuffmanTree tree_d; /*tree for distance codes*/ unsigned BFINAL = final; unsigned error = 0; size_t i; HuffmanTree_init(&tree_ll); HuffmanTree_init(&tree_d); error = generateFixedLitLenTree(&tree_ll); if(!error) error = generateFixedDistanceTree(&tree_d); if(!error) { writeBits(writer, BFINAL, 1); writeBits(writer, 1, 1); /*first bit of BTYPE*/ writeBits(writer, 0, 1); /*second bit of BTYPE*/ if(settings->use_lz77) /*LZ77 encoded*/ { uivector lz77_encoded; uivector_init(&lz77_encoded); error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize, settings->minmatch, settings->nicematch, settings->lazymatching); if(!error) writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d); uivector_cleanup(&lz77_encoded); } else /*no LZ77, but still will be Huffman compressed*/ { for(i = datapos; i < dataend; ++i) { writeBitsReversed(writer, tree_ll.codes[data[i]], tree_ll.lengths[data[i]]); } } /*add END code*/ if(!error) writeBitsReversed(writer,tree_ll.codes[256], tree_ll.lengths[256]); } /*cleanup*/ HuffmanTree_cleanup(&tree_ll); HuffmanTree_cleanup(&tree_d); return error; } static unsigned lodepng_deflatev(ucvector* out, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings) { unsigned error = 0; size_t i, blocksize, numdeflateblocks; Hash hash; LodePNGBitWriter writer; LodePNGBitWriter_init(&writer, out); if(settings->btype > 2) return 61; else if(settings->btype == 0) return deflateNoCompression(out, in, insize); else if(settings->btype == 1) blocksize = insize; else /*if(settings->btype == 2)*/ { /*on PNGs, deflate blocks of 65-262k seem to give most dense encoding*/ blocksize = insize / 8u + 8; if(blocksize < 65536) blocksize = 65536; if(blocksize > 262144) blocksize = 262144; } numdeflateblocks = (insize + blocksize - 1) / blocksize; if(numdeflateblocks == 0) numdeflateblocks = 1; error = hash_init(&hash, settings->windowsize); if(!error) { for(i = 0; i != numdeflateblocks && !error; ++i) { unsigned final = (i == numdeflateblocks - 1); size_t start = i * blocksize; size_t end = start + blocksize; if(end > insize) end = insize; if(settings->btype == 1) error = deflateFixed(&writer, &hash, in, start, end, settings, final); else if(settings->btype == 2) error = deflateDynamic(&writer, &hash, in, start, end, settings, final); } } hash_cleanup(&hash); return error; } unsigned lodepng_deflate(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings) { ucvector v = ucvector_init(*out, *outsize); unsigned error = lodepng_deflatev(&v, in, insize, settings); *out = v.data; *outsize = v.size; return error; } static unsigned deflate(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings) { if(settings->custom_deflate) { unsigned error = settings->custom_deflate(out, outsize, in, insize, settings); /*the custom deflate is allowed to have its own error codes, however, we translate it to code 111*/ return error ? 111 : 0; } else { return lodepng_deflate(out, outsize, in, insize, settings); } } #endif /*LODEPNG_COMPILE_DECODER*/ /* ////////////////////////////////////////////////////////////////////////// */ /* / Adler32 / */ /* ////////////////////////////////////////////////////////////////////////// */ static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) { unsigned s1 = adler & 0xffffu; unsigned s2 = (adler >> 16u) & 0xffffu; while(len != 0u) { unsigned i; /*at least 5552 sums can be done before the sums overflow, saving a lot of module divisions*/ unsigned amount = len > 5552u ? 5552u : len; len -= amount; for(i = 0; i != amount; ++i) { s1 += (*data++); s2 += s1; } s1 %= 65521u; s2 %= 65521u; } return (s2 << 16u) | s1; } /*Return the adler32 of the bytes data[0..len-1]*/ static unsigned adler32(const unsigned char* data, unsigned len) { return update_adler32(1u, data, len); } /* ////////////////////////////////////////////////////////////////////////// */ /* / Zlib / */ /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_DECODER static unsigned lodepng_zlib_decompressv(ucvector* out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { unsigned error = 0; unsigned CM, CINFO, FDICT; if(insize < 2) return 53; /*error, size of zlib data too small*/ /*read information from zlib header*/ if((in[0] * 256 + in[1]) % 31 != 0) { /*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/ return 24; } CM = in[0] & 15; CINFO = (in[0] >> 4) & 15; /*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/ FDICT = (in[1] >> 5) & 1; /*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/ if(CM != 8 || CINFO > 7) { /*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/ return 25; } if(FDICT != 0) { /*error: the specification of PNG says about the zlib stream: "The additional flags shall not specify a preset dictionary."*/ return 26; } error = inflatev(out, in + 2, insize - 2, settings); if(error) return error; if(!settings->ignore_adler32) { unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]); unsigned checksum = adler32(out->data, (unsigned)(out->size)); if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/ } return 0; /*no error*/ } unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { ucvector v = ucvector_init(*out, *outsize); unsigned error = lodepng_zlib_decompressv(&v, in, insize, settings); *out = v.data; *outsize = v.size; return error; } /*expected_size is expected output size, to avoid intermediate allocations. Set to 0 if not known. */ static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { unsigned error; if(settings->custom_zlib) { error = settings->custom_zlib(out, outsize, in, insize, settings); if(error) { /*the custom zlib is allowed to have its own error codes, however, we translate it to code 110*/ error = 110; /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/ if(settings->max_output_size && *outsize > settings->max_output_size) error = 109; } } else { ucvector v = ucvector_init(*out, *outsize); if(expected_size) { /*reserve the memory to avoid intermediate reallocations*/ ucvector_resize(&v, *outsize + expected_size); v.size = *outsize; } error = lodepng_zlib_decompressv(&v, in, insize, settings); *out = v.data; *outsize = v.size; } return error; } #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings) { size_t i; unsigned error; unsigned char* deflatedata = 0; size_t deflatesize = 0; error = deflate(&deflatedata, &deflatesize, in, insize, settings); *out = NULL; *outsize = 0; if(!error) { *outsize = deflatesize + 6; *out = (unsigned char*)lodepng_malloc(*outsize); if(!*out) error = 83; /*alloc fail*/ } if(!error) { unsigned ADLER32 = adler32(in, (unsigned)insize); /*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/ unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/ unsigned FLEVEL = 0; unsigned FDICT = 0; unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64; unsigned FCHECK = 31 - CMFFLG % 31; CMFFLG += FCHECK; (*out)[0] = (unsigned char)(CMFFLG >> 8); (*out)[1] = (unsigned char)(CMFFLG & 255); for(i = 0; i != deflatesize; ++i) (*out)[i + 2] = deflatedata[i]; lodepng_set32bitInt(&(*out)[*outsize - 4], ADLER32); } lodepng_free(deflatedata); return error; } /* compress using the default or custom zlib function */ static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings) { if(settings->custom_zlib) { unsigned error = settings->custom_zlib(out, outsize, in, insize, settings); /*the custom zlib is allowed to have its own error codes, however, we translate it to code 111*/ return error ? 111 : 0; } else { return lodepng_zlib_compress(out, outsize, in, insize, settings); } } #endif /*LODEPNG_COMPILE_ENCODER*/ #else /*no LODEPNG_COMPILE_ZLIB*/ #ifdef LODEPNG_COMPILE_DECODER static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { if(!settings->custom_zlib) return 87; /*no custom zlib function provided */ (void)expected_size; return settings->custom_zlib(out, outsize, in, insize, settings); } #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings) { if(!settings->custom_zlib) return 87; /*no custom zlib function provided */ return settings->custom_zlib(out, outsize, in, insize, settings); } #endif /*LODEPNG_COMPILE_ENCODER*/ #endif /*LODEPNG_COMPILE_ZLIB*/ /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_ENCODER /*this is a good tradeoff between speed and compression ratio*/ #define DEFAULT_WINDOWSIZE 2048 void lodepng_compress_settings_init(LodePNGCompressSettings* settings) { /*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/ settings->btype = 2; settings->use_lz77 = 1; settings->windowsize = DEFAULT_WINDOWSIZE; settings->minmatch = 3; settings->nicematch = 128; settings->lazymatching = 1; settings->custom_zlib = 0; settings->custom_deflate = 0; settings->custom_context = 0; } const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0}; #endif /*LODEPNG_COMPILE_ENCODER*/ #ifdef LODEPNG_COMPILE_DECODER void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) { settings->ignore_adler32 = 0; settings->ignore_nlen = 0; settings->max_output_size = 0; settings->custom_zlib = 0; settings->custom_inflate = 0; settings->custom_context = 0; } const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0, 0, 0, 0, 0}; #endif /*LODEPNG_COMPILE_DECODER*/ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ /* // End of Zlib related code. Begin of PNG related code. // */ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_PNG /* ////////////////////////////////////////////////////////////////////////// */ /* / CRC32 / */ /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_CRC static const unsigned lodepng_crc32_table0[256] = { 0x00000000u, 0x77073096u, 0xee0e612cu, 0x990951bau, 0x076dc419u, 0x706af48fu, 0xe963a535u, 0x9e6495a3u, 0x0edb8832u, 0x79dcb8a4u, 0xe0d5e91eu, 0x97d2d988u, 0x09b64c2bu, 0x7eb17cbdu, 0xe7b82d07u, 0x90bf1d91u, 0x1db71064u, 0x6ab020f2u, 0xf3b97148u, 0x84be41deu, 0x1adad47du, 0x6ddde4ebu, 0xf4d4b551u, 0x83d385c7u, 0x136c9856u, 0x646ba8c0u, 0xfd62f97au, 0x8a65c9ecu, 0x14015c4fu, 0x63066cd9u, 0xfa0f3d63u, 0x8d080df5u, 0x3b6e20c8u, 0x4c69105eu, 0xd56041e4u, 0xa2677172u, 0x3c03e4d1u, 0x4b04d447u, 0xd20d85fdu, 0xa50ab56bu, 0x35b5a8fau, 0x42b2986cu, 0xdbbbc9d6u, 0xacbcf940u, 0x32d86ce3u, 0x45df5c75u, 0xdcd60dcfu, 0xabd13d59u, 0x26d930acu, 0x51de003au, 0xc8d75180u, 0xbfd06116u, 0x21b4f4b5u, 0x56b3c423u, 0xcfba9599u, 0xb8bda50fu, 0x2802b89eu, 0x5f058808u, 0xc60cd9b2u, 0xb10be924u, 0x2f6f7c87u, 0x58684c11u, 0xc1611dabu, 0xb6662d3du, 0x76dc4190u, 0x01db7106u, 0x98d220bcu, 0xefd5102au, 0x71b18589u, 0x06b6b51fu, 0x9fbfe4a5u, 0xe8b8d433u, 0x7807c9a2u, 0x0f00f934u, 0x9609a88eu, 0xe10e9818u, 0x7f6a0dbbu, 0x086d3d2du, 0x91646c97u, 0xe6635c01u, 0x6b6b51f4u, 0x1c6c6162u, 0x856530d8u, 0xf262004eu, 0x6c0695edu, 0x1b01a57bu, 0x8208f4c1u, 0xf50fc457u, 0x65b0d9c6u, 0x12b7e950u, 0x8bbeb8eau, 0xfcb9887cu, 0x62dd1ddfu, 0x15da2d49u, 0x8cd37cf3u, 0xfbd44c65u, 0x4db26158u, 0x3ab551ceu, 0xa3bc0074u, 0xd4bb30e2u, 0x4adfa541u, 0x3dd895d7u, 0xa4d1c46du, 0xd3d6f4fbu, 0x4369e96au, 0x346ed9fcu, 0xad678846u, 0xda60b8d0u, 0x44042d73u, 0x33031de5u, 0xaa0a4c5fu, 0xdd0d7cc9u, 0x5005713cu, 0x270241aau, 0xbe0b1010u, 0xc90c2086u, 0x5768b525u, 0x206f85b3u, 0xb966d409u, 0xce61e49fu, 0x5edef90eu, 0x29d9c998u, 0xb0d09822u, 0xc7d7a8b4u, 0x59b33d17u, 0x2eb40d81u, 0xb7bd5c3bu, 0xc0ba6cadu, 0xedb88320u, 0x9abfb3b6u, 0x03b6e20cu, 0x74b1d29au, 0xead54739u, 0x9dd277afu, 0x04db2615u, 0x73dc1683u, 0xe3630b12u, 0x94643b84u, 0x0d6d6a3eu, 0x7a6a5aa8u, 0xe40ecf0bu, 0x9309ff9du, 0x0a00ae27u, 0x7d079eb1u, 0xf00f9344u, 0x8708a3d2u, 0x1e01f268u, 0x6906c2feu, 0xf762575du, 0x806567cbu, 0x196c3671u, 0x6e6b06e7u, 0xfed41b76u, 0x89d32be0u, 0x10da7a5au, 0x67dd4accu, 0xf9b9df6fu, 0x8ebeeff9u, 0x17b7be43u, 0x60b08ed5u, 0xd6d6a3e8u, 0xa1d1937eu, 0x38d8c2c4u, 0x4fdff252u, 0xd1bb67f1u, 0xa6bc5767u, 0x3fb506ddu, 0x48b2364bu, 0xd80d2bdau, 0xaf0a1b4cu, 0x36034af6u, 0x41047a60u, 0xdf60efc3u, 0xa867df55u, 0x316e8eefu, 0x4669be79u, 0xcb61b38cu, 0xbc66831au, 0x256fd2a0u, 0x5268e236u, 0xcc0c7795u, 0xbb0b4703u, 0x220216b9u, 0x5505262fu, 0xc5ba3bbeu, 0xb2bd0b28u, 0x2bb45a92u, 0x5cb36a04u, 0xc2d7ffa7u, 0xb5d0cf31u, 0x2cd99e8bu, 0x5bdeae1du, 0x9b64c2b0u, 0xec63f226u, 0x756aa39cu, 0x026d930au, 0x9c0906a9u, 0xeb0e363fu, 0x72076785u, 0x05005713u, 0x95bf4a82u, 0xe2b87a14u, 0x7bb12baeu, 0x0cb61b38u, 0x92d28e9bu, 0xe5d5be0du, 0x7cdcefb7u, 0x0bdbdf21u, 0x86d3d2d4u, 0xf1d4e242u, 0x68ddb3f8u, 0x1fda836eu, 0x81be16cdu, 0xf6b9265bu, 0x6fb077e1u, 0x18b74777u, 0x88085ae6u, 0xff0f6a70u, 0x66063bcau, 0x11010b5cu, 0x8f659effu, 0xf862ae69u, 0x616bffd3u, 0x166ccf45u, 0xa00ae278u, 0xd70dd2eeu, 0x4e048354u, 0x3903b3c2u, 0xa7672661u, 0xd06016f7u, 0x4969474du, 0x3e6e77dbu, 0xaed16a4au, 0xd9d65adcu, 0x40df0b66u, 0x37d83bf0u, 0xa9bcae53u, 0xdebb9ec5u, 0x47b2cf7fu, 0x30b5ffe9u, 0xbdbdf21cu, 0xcabac28au, 0x53b39330u, 0x24b4a3a6u, 0xbad03605u, 0xcdd70693u, 0x54de5729u, 0x23d967bfu, 0xb3667a2eu, 0xc4614ab8u, 0x5d681b02u, 0x2a6f2b94u, 0xb40bbe37u, 0xc30c8ea1u, 0x5a05df1bu, 0x2d02ef8du }; static const unsigned lodepng_crc32_table1[256] = { 0x00000000u, 0x191b3141u, 0x32366282u, 0x2b2d53c3u, 0x646cc504u, 0x7d77f445u, 0x565aa786u, 0x4f4196c7u, 0xc8d98a08u, 0xd1c2bb49u, 0xfaefe88au, 0xe3f4d9cbu, 0xacb54f0cu, 0xb5ae7e4du, 0x9e832d8eu, 0x87981ccfu, 0x4ac21251u, 0x53d92310u, 0x78f470d3u, 0x61ef4192u, 0x2eaed755u, 0x37b5e614u, 0x1c98b5d7u, 0x05838496u, 0x821b9859u, 0x9b00a918u, 0xb02dfadbu, 0xa936cb9au, 0xe6775d5du, 0xff6c6c1cu, 0xd4413fdfu, 0xcd5a0e9eu, 0x958424a2u, 0x8c9f15e3u, 0xa7b24620u, 0xbea97761u, 0xf1e8e1a6u, 0xe8f3d0e7u, 0xc3de8324u, 0xdac5b265u, 0x5d5daeaau, 0x44469febu, 0x6f6bcc28u, 0x7670fd69u, 0x39316baeu, 0x202a5aefu, 0x0b07092cu, 0x121c386du, 0xdf4636f3u, 0xc65d07b2u, 0xed705471u, 0xf46b6530u, 0xbb2af3f7u, 0xa231c2b6u, 0x891c9175u, 0x9007a034u, 0x179fbcfbu, 0x0e848dbau, 0x25a9de79u, 0x3cb2ef38u, 0x73f379ffu, 0x6ae848beu, 0x41c51b7du, 0x58de2a3cu, 0xf0794f05u, 0xe9627e44u, 0xc24f2d87u, 0xdb541cc6u, 0x94158a01u, 0x8d0ebb40u, 0xa623e883u, 0xbf38d9c2u, 0x38a0c50du, 0x21bbf44cu, 0x0a96a78fu, 0x138d96ceu, 0x5ccc0009u, 0x45d73148u, 0x6efa628bu, 0x77e153cau, 0xbabb5d54u, 0xa3a06c15u, 0x888d3fd6u, 0x91960e97u, 0xded79850u, 0xc7cca911u, 0xece1fad2u, 0xf5facb93u, 0x7262d75cu, 0x6b79e61du, 0x4054b5deu, 0x594f849fu, 0x160e1258u, 0x0f152319u, 0x243870dau, 0x3d23419bu, 0x65fd6ba7u, 0x7ce65ae6u, 0x57cb0925u, 0x4ed03864u, 0x0191aea3u, 0x188a9fe2u, 0x33a7cc21u, 0x2abcfd60u, 0xad24e1afu, 0xb43fd0eeu, 0x9f12832du, 0x8609b26cu, 0xc94824abu, 0xd05315eau, 0xfb7e4629u, 0xe2657768u, 0x2f3f79f6u, 0x362448b7u, 0x1d091b74u, 0x04122a35u, 0x4b53bcf2u, 0x52488db3u, 0x7965de70u, 0x607eef31u, 0xe7e6f3feu, 0xfefdc2bfu, 0xd5d0917cu, 0xcccba03du, 0x838a36fau, 0x9a9107bbu, 0xb1bc5478u, 0xa8a76539u, 0x3b83984bu, 0x2298a90au, 0x09b5fac9u, 0x10aecb88u, 0x5fef5d4fu, 0x46f46c0eu, 0x6dd93fcdu, 0x74c20e8cu, 0xf35a1243u, 0xea412302u, 0xc16c70c1u, 0xd8774180u, 0x9736d747u, 0x8e2de606u, 0xa500b5c5u, 0xbc1b8484u, 0x71418a1au, 0x685abb5bu, 0x4377e898u, 0x5a6cd9d9u, 0x152d4f1eu, 0x0c367e5fu, 0x271b2d9cu, 0x3e001cddu, 0xb9980012u, 0xa0833153u, 0x8bae6290u, 0x92b553d1u, 0xddf4c516u, 0xc4eff457u, 0xefc2a794u, 0xf6d996d5u, 0xae07bce9u, 0xb71c8da8u, 0x9c31de6bu, 0x852aef2au, 0xca6b79edu, 0xd37048acu, 0xf85d1b6fu, 0xe1462a2eu, 0x66de36e1u, 0x7fc507a0u, 0x54e85463u, 0x4df36522u, 0x02b2f3e5u, 0x1ba9c2a4u, 0x30849167u, 0x299fa026u, 0xe4c5aeb8u, 0xfdde9ff9u, 0xd6f3cc3au, 0xcfe8fd7bu, 0x80a96bbcu, 0x99b25afdu, 0xb29f093eu, 0xab84387fu, 0x2c1c24b0u, 0x350715f1u, 0x1e2a4632u, 0x07317773u, 0x4870e1b4u, 0x516bd0f5u, 0x7a468336u, 0x635db277u, 0xcbfad74eu, 0xd2e1e60fu, 0xf9ccb5ccu, 0xe0d7848du, 0xaf96124au, 0xb68d230bu, 0x9da070c8u, 0x84bb4189u, 0x03235d46u, 0x1a386c07u, 0x31153fc4u, 0x280e0e85u, 0x674f9842u, 0x7e54a903u, 0x5579fac0u, 0x4c62cb81u, 0x8138c51fu, 0x9823f45eu, 0xb30ea79du, 0xaa1596dcu, 0xe554001bu, 0xfc4f315au, 0xd7626299u, 0xce7953d8u, 0x49e14f17u, 0x50fa7e56u, 0x7bd72d95u, 0x62cc1cd4u, 0x2d8d8a13u, 0x3496bb52u, 0x1fbbe891u, 0x06a0d9d0u, 0x5e7ef3ecu, 0x4765c2adu, 0x6c48916eu, 0x7553a02fu, 0x3a1236e8u, 0x230907a9u, 0x0824546au, 0x113f652bu, 0x96a779e4u, 0x8fbc48a5u, 0xa4911b66u, 0xbd8a2a27u, 0xf2cbbce0u, 0xebd08da1u, 0xc0fdde62u, 0xd9e6ef23u, 0x14bce1bdu, 0x0da7d0fcu, 0x268a833fu, 0x3f91b27eu, 0x70d024b9u, 0x69cb15f8u, 0x42e6463bu, 0x5bfd777au, 0xdc656bb5u, 0xc57e5af4u, 0xee530937u, 0xf7483876u, 0xb809aeb1u, 0xa1129ff0u, 0x8a3fcc33u, 0x9324fd72u }; static const unsigned lodepng_crc32_table2[256] = { 0x00000000u, 0x01c26a37u, 0x0384d46eu, 0x0246be59u, 0x0709a8dcu, 0x06cbc2ebu, 0x048d7cb2u, 0x054f1685u, 0x0e1351b8u, 0x0fd13b8fu, 0x0d9785d6u, 0x0c55efe1u, 0x091af964u, 0x08d89353u, 0x0a9e2d0au, 0x0b5c473du, 0x1c26a370u, 0x1de4c947u, 0x1fa2771eu, 0x1e601d29u, 0x1b2f0bacu, 0x1aed619bu, 0x18abdfc2u, 0x1969b5f5u, 0x1235f2c8u, 0x13f798ffu, 0x11b126a6u, 0x10734c91u, 0x153c5a14u, 0x14fe3023u, 0x16b88e7au, 0x177ae44du, 0x384d46e0u, 0x398f2cd7u, 0x3bc9928eu, 0x3a0bf8b9u, 0x3f44ee3cu, 0x3e86840bu, 0x3cc03a52u, 0x3d025065u, 0x365e1758u, 0x379c7d6fu, 0x35dac336u, 0x3418a901u, 0x3157bf84u, 0x3095d5b3u, 0x32d36beau, 0x331101ddu, 0x246be590u, 0x25a98fa7u, 0x27ef31feu, 0x262d5bc9u, 0x23624d4cu, 0x22a0277bu, 0x20e69922u, 0x2124f315u, 0x2a78b428u, 0x2bbade1fu, 0x29fc6046u, 0x283e0a71u, 0x2d711cf4u, 0x2cb376c3u, 0x2ef5c89au, 0x2f37a2adu, 0x709a8dc0u, 0x7158e7f7u, 0x731e59aeu, 0x72dc3399u, 0x7793251cu, 0x76514f2bu, 0x7417f172u, 0x75d59b45u, 0x7e89dc78u, 0x7f4bb64fu, 0x7d0d0816u, 0x7ccf6221u, 0x798074a4u, 0x78421e93u, 0x7a04a0cau, 0x7bc6cafdu, 0x6cbc2eb0u, 0x6d7e4487u, 0x6f38fadeu, 0x6efa90e9u, 0x6bb5866cu, 0x6a77ec5bu, 0x68315202u, 0x69f33835u, 0x62af7f08u, 0x636d153fu, 0x612bab66u, 0x60e9c151u, 0x65a6d7d4u, 0x6464bde3u, 0x662203bau, 0x67e0698du, 0x48d7cb20u, 0x4915a117u, 0x4b531f4eu, 0x4a917579u, 0x4fde63fcu, 0x4e1c09cbu, 0x4c5ab792u, 0x4d98dda5u, 0x46c49a98u, 0x4706f0afu, 0x45404ef6u, 0x448224c1u, 0x41cd3244u, 0x400f5873u, 0x4249e62au, 0x438b8c1du, 0x54f16850u, 0x55330267u, 0x5775bc3eu, 0x56b7d609u, 0x53f8c08cu, 0x523aaabbu, 0x507c14e2u, 0x51be7ed5u, 0x5ae239e8u, 0x5b2053dfu, 0x5966ed86u, 0x58a487b1u, 0x5deb9134u, 0x5c29fb03u, 0x5e6f455au, 0x5fad2f6du, 0xe1351b80u, 0xe0f771b7u, 0xe2b1cfeeu, 0xe373a5d9u, 0xe63cb35cu, 0xe7fed96bu, 0xe5b86732u, 0xe47a0d05u, 0xef264a38u, 0xeee4200fu, 0xeca29e56u, 0xed60f461u, 0xe82fe2e4u, 0xe9ed88d3u, 0xebab368au, 0xea695cbdu, 0xfd13b8f0u, 0xfcd1d2c7u, 0xfe976c9eu, 0xff5506a9u, 0xfa1a102cu, 0xfbd87a1bu, 0xf99ec442u, 0xf85cae75u, 0xf300e948u, 0xf2c2837fu, 0xf0843d26u, 0xf1465711u, 0xf4094194u, 0xf5cb2ba3u, 0xf78d95fau, 0xf64fffcdu, 0xd9785d60u, 0xd8ba3757u, 0xdafc890eu, 0xdb3ee339u, 0xde71f5bcu, 0xdfb39f8bu, 0xddf521d2u, 0xdc374be5u, 0xd76b0cd8u, 0xd6a966efu, 0xd4efd8b6u, 0xd52db281u, 0xd062a404u, 0xd1a0ce33u, 0xd3e6706au, 0xd2241a5du, 0xc55efe10u, 0xc49c9427u, 0xc6da2a7eu, 0xc7184049u, 0xc25756ccu, 0xc3953cfbu, 0xc1d382a2u, 0xc011e895u, 0xcb4dafa8u, 0xca8fc59fu, 0xc8c97bc6u, 0xc90b11f1u, 0xcc440774u, 0xcd866d43u, 0xcfc0d31au, 0xce02b92du, 0x91af9640u, 0x906dfc77u, 0x922b422eu, 0x93e92819u, 0x96a63e9cu, 0x976454abu, 0x9522eaf2u, 0x94e080c5u, 0x9fbcc7f8u, 0x9e7eadcfu, 0x9c381396u, 0x9dfa79a1u, 0x98b56f24u, 0x99770513u, 0x9b31bb4au, 0x9af3d17du, 0x8d893530u, 0x8c4b5f07u, 0x8e0de15eu, 0x8fcf8b69u, 0x8a809decu, 0x8b42f7dbu, 0x89044982u, 0x88c623b5u, 0x839a6488u, 0x82580ebfu, 0x801eb0e6u, 0x81dcdad1u, 0x8493cc54u, 0x8551a663u, 0x8717183au, 0x86d5720du, 0xa9e2d0a0u, 0xa820ba97u, 0xaa6604ceu, 0xaba46ef9u, 0xaeeb787cu, 0xaf29124bu, 0xad6fac12u, 0xacadc625u, 0xa7f18118u, 0xa633eb2fu, 0xa4755576u, 0xa5b73f41u, 0xa0f829c4u, 0xa13a43f3u, 0xa37cfdaau, 0xa2be979du, 0xb5c473d0u, 0xb40619e7u, 0xb640a7beu, 0xb782cd89u, 0xb2cddb0cu, 0xb30fb13bu, 0xb1490f62u, 0xb08b6555u, 0xbbd72268u, 0xba15485fu, 0xb853f606u, 0xb9919c31u, 0xbcde8ab4u, 0xbd1ce083u, 0xbf5a5edau, 0xbe9834edu }; static const unsigned lodepng_crc32_table3[256] = { 0x00000000u, 0xb8bc6765u, 0xaa09c88bu, 0x12b5afeeu, 0x8f629757u, 0x37def032u, 0x256b5fdcu, 0x9dd738b9u, 0xc5b428efu, 0x7d084f8au, 0x6fbde064u, 0xd7018701u, 0x4ad6bfb8u, 0xf26ad8ddu, 0xe0df7733u, 0x58631056u, 0x5019579fu, 0xe8a530fau, 0xfa109f14u, 0x42acf871u, 0xdf7bc0c8u, 0x67c7a7adu, 0x75720843u, 0xcdce6f26u, 0x95ad7f70u, 0x2d111815u, 0x3fa4b7fbu, 0x8718d09eu, 0x1acfe827u, 0xa2738f42u, 0xb0c620acu, 0x087a47c9u, 0xa032af3eu, 0x188ec85bu, 0x0a3b67b5u, 0xb28700d0u, 0x2f503869u, 0x97ec5f0cu, 0x8559f0e2u, 0x3de59787u, 0x658687d1u, 0xdd3ae0b4u, 0xcf8f4f5au, 0x7733283fu, 0xeae41086u, 0x525877e3u, 0x40edd80du, 0xf851bf68u, 0xf02bf8a1u, 0x48979fc4u, 0x5a22302au, 0xe29e574fu, 0x7f496ff6u, 0xc7f50893u, 0xd540a77du, 0x6dfcc018u, 0x359fd04eu, 0x8d23b72bu, 0x9f9618c5u, 0x272a7fa0u, 0xbafd4719u, 0x0241207cu, 0x10f48f92u, 0xa848e8f7u, 0x9b14583du, 0x23a83f58u, 0x311d90b6u, 0x89a1f7d3u, 0x1476cf6au, 0xaccaa80fu, 0xbe7f07e1u, 0x06c36084u, 0x5ea070d2u, 0xe61c17b7u, 0xf4a9b859u, 0x4c15df3cu, 0xd1c2e785u, 0x697e80e0u, 0x7bcb2f0eu, 0xc377486bu, 0xcb0d0fa2u, 0x73b168c7u, 0x6104c729u, 0xd9b8a04cu, 0x446f98f5u, 0xfcd3ff90u, 0xee66507eu, 0x56da371bu, 0x0eb9274du, 0xb6054028u, 0xa4b0efc6u, 0x1c0c88a3u, 0x81dbb01au, 0x3967d77fu, 0x2bd27891u, 0x936e1ff4u, 0x3b26f703u, 0x839a9066u, 0x912f3f88u, 0x299358edu, 0xb4446054u, 0x0cf80731u, 0x1e4da8dfu, 0xa6f1cfbau, 0xfe92dfecu, 0x462eb889u, 0x549b1767u, 0xec277002u, 0x71f048bbu, 0xc94c2fdeu, 0xdbf98030u, 0x6345e755u, 0x6b3fa09cu, 0xd383c7f9u, 0xc1366817u, 0x798a0f72u, 0xe45d37cbu, 0x5ce150aeu, 0x4e54ff40u, 0xf6e89825u, 0xae8b8873u, 0x1637ef16u, 0x048240f8u, 0xbc3e279du, 0x21e91f24u, 0x99557841u, 0x8be0d7afu, 0x335cb0cau, 0xed59b63bu, 0x55e5d15eu, 0x47507eb0u, 0xffec19d5u, 0x623b216cu, 0xda874609u, 0xc832e9e7u, 0x708e8e82u, 0x28ed9ed4u, 0x9051f9b1u, 0x82e4565fu, 0x3a58313au, 0xa78f0983u, 0x1f336ee6u, 0x0d86c108u, 0xb53aa66du, 0xbd40e1a4u, 0x05fc86c1u, 0x1749292fu, 0xaff54e4au, 0x322276f3u, 0x8a9e1196u, 0x982bbe78u, 0x2097d91du, 0x78f4c94bu, 0xc048ae2eu, 0xd2fd01c0u, 0x6a4166a5u, 0xf7965e1cu, 0x4f2a3979u, 0x5d9f9697u, 0xe523f1f2u, 0x4d6b1905u, 0xf5d77e60u, 0xe762d18eu, 0x5fdeb6ebu, 0xc2098e52u, 0x7ab5e937u, 0x680046d9u, 0xd0bc21bcu, 0x88df31eau, 0x3063568fu, 0x22d6f961u, 0x9a6a9e04u, 0x07bda6bdu, 0xbf01c1d8u, 0xadb46e36u, 0x15080953u, 0x1d724e9au, 0xa5ce29ffu, 0xb77b8611u, 0x0fc7e174u, 0x9210d9cdu, 0x2aacbea8u, 0x38191146u, 0x80a57623u, 0xd8c66675u, 0x607a0110u, 0x72cfaefeu, 0xca73c99bu, 0x57a4f122u, 0xef189647u, 0xfdad39a9u, 0x45115eccu, 0x764dee06u, 0xcef18963u, 0xdc44268du, 0x64f841e8u, 0xf92f7951u, 0x41931e34u, 0x5326b1dau, 0xeb9ad6bfu, 0xb3f9c6e9u, 0x0b45a18cu, 0x19f00e62u, 0xa14c6907u, 0x3c9b51beu, 0x842736dbu, 0x96929935u, 0x2e2efe50u, 0x2654b999u, 0x9ee8defcu, 0x8c5d7112u, 0x34e11677u, 0xa9362eceu, 0x118a49abu, 0x033fe645u, 0xbb838120u, 0xe3e09176u, 0x5b5cf613u, 0x49e959fdu, 0xf1553e98u, 0x6c820621u, 0xd43e6144u, 0xc68bceaau, 0x7e37a9cfu, 0xd67f4138u, 0x6ec3265du, 0x7c7689b3u, 0xc4caeed6u, 0x591dd66fu, 0xe1a1b10au, 0xf3141ee4u, 0x4ba87981u, 0x13cb69d7u, 0xab770eb2u, 0xb9c2a15cu, 0x017ec639u, 0x9ca9fe80u, 0x241599e5u, 0x36a0360bu, 0x8e1c516eu, 0x866616a7u, 0x3eda71c2u, 0x2c6fde2cu, 0x94d3b949u, 0x090481f0u, 0xb1b8e695u, 0xa30d497bu, 0x1bb12e1eu, 0x43d23e48u, 0xfb6e592du, 0xe9dbf6c3u, 0x516791a6u, 0xccb0a91fu, 0x740cce7au, 0x66b96194u, 0xde0506f1u }; static const unsigned lodepng_crc32_table4[256] = { 0x00000000u, 0x3d6029b0u, 0x7ac05360u, 0x47a07ad0u, 0xf580a6c0u, 0xc8e08f70u, 0x8f40f5a0u, 0xb220dc10u, 0x30704bc1u, 0x0d106271u, 0x4ab018a1u, 0x77d03111u, 0xc5f0ed01u, 0xf890c4b1u, 0xbf30be61u, 0x825097d1u, 0x60e09782u, 0x5d80be32u, 0x1a20c4e2u, 0x2740ed52u, 0x95603142u, 0xa80018f2u, 0xefa06222u, 0xd2c04b92u, 0x5090dc43u, 0x6df0f5f3u, 0x2a508f23u, 0x1730a693u, 0xa5107a83u, 0x98705333u, 0xdfd029e3u, 0xe2b00053u, 0xc1c12f04u, 0xfca106b4u, 0xbb017c64u, 0x866155d4u, 0x344189c4u, 0x0921a074u, 0x4e81daa4u, 0x73e1f314u, 0xf1b164c5u, 0xccd14d75u, 0x8b7137a5u, 0xb6111e15u, 0x0431c205u, 0x3951ebb5u, 0x7ef19165u, 0x4391b8d5u, 0xa121b886u, 0x9c419136u, 0xdbe1ebe6u, 0xe681c256u, 0x54a11e46u, 0x69c137f6u, 0x2e614d26u, 0x13016496u, 0x9151f347u, 0xac31daf7u, 0xeb91a027u, 0xd6f18997u, 0x64d15587u, 0x59b17c37u, 0x1e1106e7u, 0x23712f57u, 0x58f35849u, 0x659371f9u, 0x22330b29u, 0x1f532299u, 0xad73fe89u, 0x9013d739u, 0xd7b3ade9u, 0xead38459u, 0x68831388u, 0x55e33a38u, 0x124340e8u, 0x2f236958u, 0x9d03b548u, 0xa0639cf8u, 0xe7c3e628u, 0xdaa3cf98u, 0x3813cfcbu, 0x0573e67bu, 0x42d39cabu, 0x7fb3b51bu, 0xcd93690bu, 0xf0f340bbu, 0xb7533a6bu, 0x8a3313dbu, 0x0863840au, 0x3503adbau, 0x72a3d76au, 0x4fc3fedau, 0xfde322cau, 0xc0830b7au, 0x872371aau, 0xba43581au, 0x9932774du, 0xa4525efdu, 0xe3f2242du, 0xde920d9du, 0x6cb2d18du, 0x51d2f83du, 0x167282edu, 0x2b12ab5du, 0xa9423c8cu, 0x9422153cu, 0xd3826fecu, 0xeee2465cu, 0x5cc29a4cu, 0x61a2b3fcu, 0x2602c92cu, 0x1b62e09cu, 0xf9d2e0cfu, 0xc4b2c97fu, 0x8312b3afu, 0xbe729a1fu, 0x0c52460fu, 0x31326fbfu, 0x7692156fu, 0x4bf23cdfu, 0xc9a2ab0eu, 0xf4c282beu, 0xb362f86eu, 0x8e02d1deu, 0x3c220dceu, 0x0142247eu, 0x46e25eaeu, 0x7b82771eu, 0xb1e6b092u, 0x8c869922u, 0xcb26e3f2u, 0xf646ca42u, 0x44661652u, 0x79063fe2u, 0x3ea64532u, 0x03c66c82u, 0x8196fb53u, 0xbcf6d2e3u, 0xfb56a833u, 0xc6368183u, 0x74165d93u, 0x49767423u, 0x0ed60ef3u, 0x33b62743u, 0xd1062710u, 0xec660ea0u, 0xabc67470u, 0x96a65dc0u, 0x248681d0u, 0x19e6a860u, 0x5e46d2b0u, 0x6326fb00u, 0xe1766cd1u, 0xdc164561u, 0x9bb63fb1u, 0xa6d61601u, 0x14f6ca11u, 0x2996e3a1u, 0x6e369971u, 0x5356b0c1u, 0x70279f96u, 0x4d47b626u, 0x0ae7ccf6u, 0x3787e546u, 0x85a73956u, 0xb8c710e6u, 0xff676a36u, 0xc2074386u, 0x4057d457u, 0x7d37fde7u, 0x3a978737u, 0x07f7ae87u, 0xb5d77297u, 0x88b75b27u, 0xcf1721f7u, 0xf2770847u, 0x10c70814u, 0x2da721a4u, 0x6a075b74u, 0x576772c4u, 0xe547aed4u, 0xd8278764u, 0x9f87fdb4u, 0xa2e7d404u, 0x20b743d5u, 0x1dd76a65u, 0x5a7710b5u, 0x67173905u, 0xd537e515u, 0xe857cca5u, 0xaff7b675u, 0x92979fc5u, 0xe915e8dbu, 0xd475c16bu, 0x93d5bbbbu, 0xaeb5920bu, 0x1c954e1bu, 0x21f567abu, 0x66551d7bu, 0x5b3534cbu, 0xd965a31au, 0xe4058aaau, 0xa3a5f07au, 0x9ec5d9cau, 0x2ce505dau, 0x11852c6au, 0x562556bau, 0x6b457f0au, 0x89f57f59u, 0xb49556e9u, 0xf3352c39u, 0xce550589u, 0x7c75d999u, 0x4115f029u, 0x06b58af9u, 0x3bd5a349u, 0xb9853498u, 0x84e51d28u, 0xc34567f8u, 0xfe254e48u, 0x4c059258u, 0x7165bbe8u, 0x36c5c138u, 0x0ba5e888u, 0x28d4c7dfu, 0x15b4ee6fu, 0x521494bfu, 0x6f74bd0fu, 0xdd54611fu, 0xe03448afu, 0xa794327fu, 0x9af41bcfu, 0x18a48c1eu, 0x25c4a5aeu, 0x6264df7eu, 0x5f04f6ceu, 0xed242adeu, 0xd044036eu, 0x97e479beu, 0xaa84500eu, 0x4834505du, 0x755479edu, 0x32f4033du, 0x0f942a8du, 0xbdb4f69du, 0x80d4df2du, 0xc774a5fdu, 0xfa148c4du, 0x78441b9cu, 0x4524322cu, 0x028448fcu, 0x3fe4614cu, 0x8dc4bd5cu, 0xb0a494ecu, 0xf704ee3cu, 0xca64c78cu }; static const unsigned lodepng_crc32_table5[256] = { 0x00000000u, 0xcb5cd3a5u, 0x4dc8a10bu, 0x869472aeu, 0x9b914216u, 0x50cd91b3u, 0xd659e31du, 0x1d0530b8u, 0xec53826du, 0x270f51c8u, 0xa19b2366u, 0x6ac7f0c3u, 0x77c2c07bu, 0xbc9e13deu, 0x3a0a6170u, 0xf156b2d5u, 0x03d6029bu, 0xc88ad13eu, 0x4e1ea390u, 0x85427035u, 0x9847408du, 0x531b9328u, 0xd58fe186u, 0x1ed33223u, 0xef8580f6u, 0x24d95353u, 0xa24d21fdu, 0x6911f258u, 0x7414c2e0u, 0xbf481145u, 0x39dc63ebu, 0xf280b04eu, 0x07ac0536u, 0xccf0d693u, 0x4a64a43du, 0x81387798u, 0x9c3d4720u, 0x57619485u, 0xd1f5e62bu, 0x1aa9358eu, 0xebff875bu, 0x20a354feu, 0xa6372650u, 0x6d6bf5f5u, 0x706ec54du, 0xbb3216e8u, 0x3da66446u, 0xf6fab7e3u, 0x047a07adu, 0xcf26d408u, 0x49b2a6a6u, 0x82ee7503u, 0x9feb45bbu, 0x54b7961eu, 0xd223e4b0u, 0x197f3715u, 0xe82985c0u, 0x23755665u, 0xa5e124cbu, 0x6ebdf76eu, 0x73b8c7d6u, 0xb8e41473u, 0x3e7066ddu, 0xf52cb578u, 0x0f580a6cu, 0xc404d9c9u, 0x4290ab67u, 0x89cc78c2u, 0x94c9487au, 0x5f959bdfu, 0xd901e971u, 0x125d3ad4u, 0xe30b8801u, 0x28575ba4u, 0xaec3290au, 0x659ffaafu, 0x789aca17u, 0xb3c619b2u, 0x35526b1cu, 0xfe0eb8b9u, 0x0c8e08f7u, 0xc7d2db52u, 0x4146a9fcu, 0x8a1a7a59u, 0x971f4ae1u, 0x5c439944u, 0xdad7ebeau, 0x118b384fu, 0xe0dd8a9au, 0x2b81593fu, 0xad152b91u, 0x6649f834u, 0x7b4cc88cu, 0xb0101b29u, 0x36846987u, 0xfdd8ba22u, 0x08f40f5au, 0xc3a8dcffu, 0x453cae51u, 0x8e607df4u, 0x93654d4cu, 0x58399ee9u, 0xdeadec47u, 0x15f13fe2u, 0xe4a78d37u, 0x2ffb5e92u, 0xa96f2c3cu, 0x6233ff99u, 0x7f36cf21u, 0xb46a1c84u, 0x32fe6e2au, 0xf9a2bd8fu, 0x0b220dc1u, 0xc07ede64u, 0x46eaaccau, 0x8db67f6fu, 0x90b34fd7u, 0x5bef9c72u, 0xdd7beedcu, 0x16273d79u, 0xe7718facu, 0x2c2d5c09u, 0xaab92ea7u, 0x61e5fd02u, 0x7ce0cdbau, 0xb7bc1e1fu, 0x31286cb1u, 0xfa74bf14u, 0x1eb014d8u, 0xd5ecc77du, 0x5378b5d3u, 0x98246676u, 0x852156ceu, 0x4e7d856bu, 0xc8e9f7c5u, 0x03b52460u, 0xf2e396b5u, 0x39bf4510u, 0xbf2b37beu, 0x7477e41bu, 0x6972d4a3u, 0xa22e0706u, 0x24ba75a8u, 0xefe6a60du, 0x1d661643u, 0xd63ac5e6u, 0x50aeb748u, 0x9bf264edu, 0x86f75455u, 0x4dab87f0u, 0xcb3ff55eu, 0x006326fbu, 0xf135942eu, 0x3a69478bu, 0xbcfd3525u, 0x77a1e680u, 0x6aa4d638u, 0xa1f8059du, 0x276c7733u, 0xec30a496u, 0x191c11eeu, 0xd240c24bu, 0x54d4b0e5u, 0x9f886340u, 0x828d53f8u, 0x49d1805du, 0xcf45f2f3u, 0x04192156u, 0xf54f9383u, 0x3e134026u, 0xb8873288u, 0x73dbe12du, 0x6eded195u, 0xa5820230u, 0x2316709eu, 0xe84aa33bu, 0x1aca1375u, 0xd196c0d0u, 0x5702b27eu, 0x9c5e61dbu, 0x815b5163u, 0x4a0782c6u, 0xcc93f068u, 0x07cf23cdu, 0xf6999118u, 0x3dc542bdu, 0xbb513013u, 0x700de3b6u, 0x6d08d30eu, 0xa65400abu, 0x20c07205u, 0xeb9ca1a0u, 0x11e81eb4u, 0xdab4cd11u, 0x5c20bfbfu, 0x977c6c1au, 0x8a795ca2u, 0x41258f07u, 0xc7b1fda9u, 0x0ced2e0cu, 0xfdbb9cd9u, 0x36e74f7cu, 0xb0733dd2u, 0x7b2fee77u, 0x662adecfu, 0xad760d6au, 0x2be27fc4u, 0xe0beac61u, 0x123e1c2fu, 0xd962cf8au, 0x5ff6bd24u, 0x94aa6e81u, 0x89af5e39u, 0x42f38d9cu, 0xc467ff32u, 0x0f3b2c97u, 0xfe6d9e42u, 0x35314de7u, 0xb3a53f49u, 0x78f9ececu, 0x65fcdc54u, 0xaea00ff1u, 0x28347d5fu, 0xe368aefau, 0x16441b82u, 0xdd18c827u, 0x5b8cba89u, 0x90d0692cu, 0x8dd55994u, 0x46898a31u, 0xc01df89fu, 0x0b412b3au, 0xfa1799efu, 0x314b4a4au, 0xb7df38e4u, 0x7c83eb41u, 0x6186dbf9u, 0xaada085cu, 0x2c4e7af2u, 0xe712a957u, 0x15921919u, 0xdececabcu, 0x585ab812u, 0x93066bb7u, 0x8e035b0fu, 0x455f88aau, 0xc3cbfa04u, 0x089729a1u, 0xf9c19b74u, 0x329d48d1u, 0xb4093a7fu, 0x7f55e9dau, 0x6250d962u, 0xa90c0ac7u, 0x2f987869u, 0xe4c4abccu }; static const unsigned lodepng_crc32_table6[256] = { 0x00000000u, 0xa6770bb4u, 0x979f1129u, 0x31e81a9du, 0xf44f2413u, 0x52382fa7u, 0x63d0353au, 0xc5a73e8eu, 0x33ef4e67u, 0x959845d3u, 0xa4705f4eu, 0x020754fau, 0xc7a06a74u, 0x61d761c0u, 0x503f7b5du, 0xf64870e9u, 0x67de9cceu, 0xc1a9977au, 0xf0418de7u, 0x56368653u, 0x9391b8ddu, 0x35e6b369u, 0x040ea9f4u, 0xa279a240u, 0x5431d2a9u, 0xf246d91du, 0xc3aec380u, 0x65d9c834u, 0xa07ef6bau, 0x0609fd0eu, 0x37e1e793u, 0x9196ec27u, 0xcfbd399cu, 0x69ca3228u, 0x582228b5u, 0xfe552301u, 0x3bf21d8fu, 0x9d85163bu, 0xac6d0ca6u, 0x0a1a0712u, 0xfc5277fbu, 0x5a257c4fu, 0x6bcd66d2u, 0xcdba6d66u, 0x081d53e8u, 0xae6a585cu, 0x9f8242c1u, 0x39f54975u, 0xa863a552u, 0x0e14aee6u, 0x3ffcb47bu, 0x998bbfcfu, 0x5c2c8141u, 0xfa5b8af5u, 0xcbb39068u, 0x6dc49bdcu, 0x9b8ceb35u, 0x3dfbe081u, 0x0c13fa1cu, 0xaa64f1a8u, 0x6fc3cf26u, 0xc9b4c492u, 0xf85cde0fu, 0x5e2bd5bbu, 0x440b7579u, 0xe27c7ecdu, 0xd3946450u, 0x75e36fe4u, 0xb044516au, 0x16335adeu, 0x27db4043u, 0x81ac4bf7u, 0x77e43b1eu, 0xd19330aau, 0xe07b2a37u, 0x460c2183u, 0x83ab1f0du, 0x25dc14b9u, 0x14340e24u, 0xb2430590u, 0x23d5e9b7u, 0x85a2e203u, 0xb44af89eu, 0x123df32au, 0xd79acda4u, 0x71edc610u, 0x4005dc8du, 0xe672d739u, 0x103aa7d0u, 0xb64dac64u, 0x87a5b6f9u, 0x21d2bd4du, 0xe47583c3u, 0x42028877u, 0x73ea92eau, 0xd59d995eu, 0x8bb64ce5u, 0x2dc14751u, 0x1c295dccu, 0xba5e5678u, 0x7ff968f6u, 0xd98e6342u, 0xe86679dfu, 0x4e11726bu, 0xb8590282u, 0x1e2e0936u, 0x2fc613abu, 0x89b1181fu, 0x4c162691u, 0xea612d25u, 0xdb8937b8u, 0x7dfe3c0cu, 0xec68d02bu, 0x4a1fdb9fu, 0x7bf7c102u, 0xdd80cab6u, 0x1827f438u, 0xbe50ff8cu, 0x8fb8e511u, 0x29cfeea5u, 0xdf879e4cu, 0x79f095f8u, 0x48188f65u, 0xee6f84d1u, 0x2bc8ba5fu, 0x8dbfb1ebu, 0xbc57ab76u, 0x1a20a0c2u, 0x8816eaf2u, 0x2e61e146u, 0x1f89fbdbu, 0xb9fef06fu, 0x7c59cee1u, 0xda2ec555u, 0xebc6dfc8u, 0x4db1d47cu, 0xbbf9a495u, 0x1d8eaf21u, 0x2c66b5bcu, 0x8a11be08u, 0x4fb68086u, 0xe9c18b32u, 0xd82991afu, 0x7e5e9a1bu, 0xefc8763cu, 0x49bf7d88u, 0x78576715u, 0xde206ca1u, 0x1b87522fu, 0xbdf0599bu, 0x8c184306u, 0x2a6f48b2u, 0xdc27385bu, 0x7a5033efu, 0x4bb82972u, 0xedcf22c6u, 0x28681c48u, 0x8e1f17fcu, 0xbff70d61u, 0x198006d5u, 0x47abd36eu, 0xe1dcd8dau, 0xd034c247u, 0x7643c9f3u, 0xb3e4f77du, 0x1593fcc9u, 0x247be654u, 0x820cede0u, 0x74449d09u, 0xd23396bdu, 0xe3db8c20u, 0x45ac8794u, 0x800bb91au, 0x267cb2aeu, 0x1794a833u, 0xb1e3a387u, 0x20754fa0u, 0x86024414u, 0xb7ea5e89u, 0x119d553du, 0xd43a6bb3u, 0x724d6007u, 0x43a57a9au, 0xe5d2712eu, 0x139a01c7u, 0xb5ed0a73u, 0x840510eeu, 0x22721b5au, 0xe7d525d4u, 0x41a22e60u, 0x704a34fdu, 0xd63d3f49u, 0xcc1d9f8bu, 0x6a6a943fu, 0x5b828ea2u, 0xfdf58516u, 0x3852bb98u, 0x9e25b02cu, 0xafcdaab1u, 0x09baa105u, 0xfff2d1ecu, 0x5985da58u, 0x686dc0c5u, 0xce1acb71u, 0x0bbdf5ffu, 0xadcafe4bu, 0x9c22e4d6u, 0x3a55ef62u, 0xabc30345u, 0x0db408f1u, 0x3c5c126cu, 0x9a2b19d8u, 0x5f8c2756u, 0xf9fb2ce2u, 0xc813367fu, 0x6e643dcbu, 0x982c4d22u, 0x3e5b4696u, 0x0fb35c0bu, 0xa9c457bfu, 0x6c636931u, 0xca146285u, 0xfbfc7818u, 0x5d8b73acu, 0x03a0a617u, 0xa5d7ada3u, 0x943fb73eu, 0x3248bc8au, 0xf7ef8204u, 0x519889b0u, 0x6070932du, 0xc6079899u, 0x304fe870u, 0x9638e3c4u, 0xa7d0f959u, 0x01a7f2edu, 0xc400cc63u, 0x6277c7d7u, 0x539fdd4au, 0xf5e8d6feu, 0x647e3ad9u, 0xc209316du, 0xf3e12bf0u, 0x55962044u, 0x90311ecau, 0x3646157eu, 0x07ae0fe3u, 0xa1d90457u, 0x579174beu, 0xf1e67f0au, 0xc00e6597u, 0x66796e23u, 0xa3de50adu, 0x05a95b19u, 0x34414184u, 0x92364a30u }; static const unsigned lodepng_crc32_table7[256] = { 0x00000000u, 0xccaa009eu, 0x4225077du, 0x8e8f07e3u, 0x844a0efau, 0x48e00e64u, 0xc66f0987u, 0x0ac50919u, 0xd3e51bb5u, 0x1f4f1b2bu, 0x91c01cc8u, 0x5d6a1c56u, 0x57af154fu, 0x9b0515d1u, 0x158a1232u, 0xd92012acu, 0x7cbb312bu, 0xb01131b5u, 0x3e9e3656u, 0xf23436c8u, 0xf8f13fd1u, 0x345b3f4fu, 0xbad438acu, 0x767e3832u, 0xaf5e2a9eu, 0x63f42a00u, 0xed7b2de3u, 0x21d12d7du, 0x2b142464u, 0xe7be24fau, 0x69312319u, 0xa59b2387u, 0xf9766256u, 0x35dc62c8u, 0xbb53652bu, 0x77f965b5u, 0x7d3c6cacu, 0xb1966c32u, 0x3f196bd1u, 0xf3b36b4fu, 0x2a9379e3u, 0xe639797du, 0x68b67e9eu, 0xa41c7e00u, 0xaed97719u, 0x62737787u, 0xecfc7064u, 0x205670fau, 0x85cd537du, 0x496753e3u, 0xc7e85400u, 0x0b42549eu, 0x01875d87u, 0xcd2d5d19u, 0x43a25afau, 0x8f085a64u, 0x562848c8u, 0x9a824856u, 0x140d4fb5u, 0xd8a74f2bu, 0xd2624632u, 0x1ec846acu, 0x9047414fu, 0x5ced41d1u, 0x299dc2edu, 0xe537c273u, 0x6bb8c590u, 0xa712c50eu, 0xadd7cc17u, 0x617dcc89u, 0xeff2cb6au, 0x2358cbf4u, 0xfa78d958u, 0x36d2d9c6u, 0xb85dde25u, 0x74f7debbu, 0x7e32d7a2u, 0xb298d73cu, 0x3c17d0dfu, 0xf0bdd041u, 0x5526f3c6u, 0x998cf358u, 0x1703f4bbu, 0xdba9f425u, 0xd16cfd3cu, 0x1dc6fda2u, 0x9349fa41u, 0x5fe3fadfu, 0x86c3e873u, 0x4a69e8edu, 0xc4e6ef0eu, 0x084cef90u, 0x0289e689u, 0xce23e617u, 0x40ace1f4u, 0x8c06e16au, 0xd0eba0bbu, 0x1c41a025u, 0x92cea7c6u, 0x5e64a758u, 0x54a1ae41u, 0x980baedfu, 0x1684a93cu, 0xda2ea9a2u, 0x030ebb0eu, 0xcfa4bb90u, 0x412bbc73u, 0x8d81bcedu, 0x8744b5f4u, 0x4beeb56au, 0xc561b289u, 0x09cbb217u, 0xac509190u, 0x60fa910eu, 0xee7596edu, 0x22df9673u, 0x281a9f6au, 0xe4b09ff4u, 0x6a3f9817u, 0xa6959889u, 0x7fb58a25u, 0xb31f8abbu, 0x3d908d58u, 0xf13a8dc6u, 0xfbff84dfu, 0x37558441u, 0xb9da83a2u, 0x7570833cu, 0x533b85dau, 0x9f918544u, 0x111e82a7u, 0xddb48239u, 0xd7718b20u, 0x1bdb8bbeu, 0x95548c5du, 0x59fe8cc3u, 0x80de9e6fu, 0x4c749ef1u, 0xc2fb9912u, 0x0e51998cu, 0x04949095u, 0xc83e900bu, 0x46b197e8u, 0x8a1b9776u, 0x2f80b4f1u, 0xe32ab46fu, 0x6da5b38cu, 0xa10fb312u, 0xabcaba0bu, 0x6760ba95u, 0xe9efbd76u, 0x2545bde8u, 0xfc65af44u, 0x30cfafdau, 0xbe40a839u, 0x72eaa8a7u, 0x782fa1beu, 0xb485a120u, 0x3a0aa6c3u, 0xf6a0a65du, 0xaa4de78cu, 0x66e7e712u, 0xe868e0f1u, 0x24c2e06fu, 0x2e07e976u, 0xe2ade9e8u, 0x6c22ee0bu, 0xa088ee95u, 0x79a8fc39u, 0xb502fca7u, 0x3b8dfb44u, 0xf727fbdau, 0xfde2f2c3u, 0x3148f25du, 0xbfc7f5beu, 0x736df520u, 0xd6f6d6a7u, 0x1a5cd639u, 0x94d3d1dau, 0x5879d144u, 0x52bcd85du, 0x9e16d8c3u, 0x1099df20u, 0xdc33dfbeu, 0x0513cd12u, 0xc9b9cd8cu, 0x4736ca6fu, 0x8b9ccaf1u, 0x8159c3e8u, 0x4df3c376u, 0xc37cc495u, 0x0fd6c40bu, 0x7aa64737u, 0xb60c47a9u, 0x3883404au, 0xf42940d4u, 0xfeec49cdu, 0x32464953u, 0xbcc94eb0u, 0x70634e2eu, 0xa9435c82u, 0x65e95c1cu, 0xeb665bffu, 0x27cc5b61u, 0x2d095278u, 0xe1a352e6u, 0x6f2c5505u, 0xa386559bu, 0x061d761cu, 0xcab77682u, 0x44387161u, 0x889271ffu, 0x825778e6u, 0x4efd7878u, 0xc0727f9bu, 0x0cd87f05u, 0xd5f86da9u, 0x19526d37u, 0x97dd6ad4u, 0x5b776a4au, 0x51b26353u, 0x9d1863cdu, 0x1397642eu, 0xdf3d64b0u, 0x83d02561u, 0x4f7a25ffu, 0xc1f5221cu, 0x0d5f2282u, 0x079a2b9bu, 0xcb302b05u, 0x45bf2ce6u, 0x89152c78u, 0x50353ed4u, 0x9c9f3e4au, 0x121039a9u, 0xdeba3937u, 0xd47f302eu, 0x18d530b0u, 0x965a3753u, 0x5af037cdu, 0xff6b144au, 0x33c114d4u, 0xbd4e1337u, 0x71e413a9u, 0x7b211ab0u, 0xb78b1a2eu, 0x39041dcdu, 0xf5ae1d53u, 0x2c8e0fffu, 0xe0240f61u, 0x6eab0882u, 0xa201081cu, 0xa8c40105u, 0x646e019bu, 0xeae10678u, 0x264b06e6u }; /* Computes the cyclic redundancy check as used by PNG chunks*/ unsigned lodepng_crc32(const unsigned char* data, size_t length) { /*Using the Slicing by Eight algorithm*/ unsigned r = 0xffffffffu; while(length >= 8) { r = lodepng_crc32_table7[(data[0] ^ (r & 0xffu))] ^ lodepng_crc32_table6[(data[1] ^ ((r >> 8) & 0xffu))] ^ lodepng_crc32_table5[(data[2] ^ ((r >> 16) & 0xffu))] ^ lodepng_crc32_table4[(data[3] ^ ((r >> 24) & 0xffu))] ^ lodepng_crc32_table3[data[4]] ^ lodepng_crc32_table2[data[5]] ^ lodepng_crc32_table1[data[6]] ^ lodepng_crc32_table0[data[7]]; data += 8; length -= 8; } while(length--) { r = lodepng_crc32_table0[(r ^ *data++) & 0xffu] ^ (r >> 8); } return r ^ 0xffffffffu; } #else /* LODEPNG_COMPILE_CRC */ /*in this case, the function is only declared here, and must be defined externally so that it will be linked in. Example implementation that uses a much smaller lookup table for memory constrained cases: unsigned lodepng_crc32(const unsigned char* data, size_t length) { unsigned r = 0xffffffffu; static const unsigned table[16] = { 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c, 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c }; while(length--) { r = table[(r ^ *data) & 0xf] ^ (r >> 4); r = table[(r ^ (*data >> 4)) & 0xf] ^ (r >> 4); data++; } return r ^ 0xffffffffu; } */ unsigned lodepng_crc32(const unsigned char* data, size_t length); #endif /* LODEPNG_COMPILE_CRC */ /* ////////////////////////////////////////////////////////////////////////// */ /* / Reading and writing PNG color channel bits / */ /* ////////////////////////////////////////////////////////////////////////// */ /* The color channel bits of less-than-8-bit pixels are read with the MSB of bytes first, so LodePNGBitWriter and LodePNGBitReader can't be used for those. */ static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream) { unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1); ++(*bitpointer); return result; } /* TODO: make this faster */ static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) { unsigned result = 0; size_t i; for(i = 0 ; i < nbits; ++i) { result <<= 1u; result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream); } return result; } static void setBitOfReversedStream(size_t* bitpointer, unsigned char* bitstream, unsigned char bit) { /*the current bit in bitstream may be 0 or 1 for this to work*/ if(bit == 0) bitstream[(*bitpointer) >> 3u] &= (unsigned char)(~(1u << (7u - ((*bitpointer) & 7u)))); else bitstream[(*bitpointer) >> 3u] |= (1u << (7u - ((*bitpointer) & 7u))); ++(*bitpointer); } /* ////////////////////////////////////////////////////////////////////////// */ /* / PNG chunks / */ /* ////////////////////////////////////////////////////////////////////////// */ unsigned lodepng_chunk_length(const unsigned char* chunk) { return lodepng_read32bitInt(chunk); } void lodepng_chunk_type(char type[5], const unsigned char* chunk) { unsigned i; for(i = 0; i != 4; ++i) type[i] = (char)chunk[4 + i]; type[4] = 0; /*null termination char*/ } unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type) { if(lodepng_strlen(type) != 4) return 0; return (chunk[4] == type[0] && chunk[5] == type[1] && chunk[6] == type[2] && chunk[7] == type[3]); } /* chunk type name must exist only out of alphabetic characters a-z or A-Z */ static unsigned char lodepng_chunk_type_name_valid(const unsigned char* chunk) { unsigned i; for(i = 0; i != 4; ++i) { char c = (char)chunk[4 + i]; if(!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))) { return 0; /* not valid */ } } return 1; /* valid */ } unsigned char lodepng_chunk_ancillary(const unsigned char* chunk) { return((chunk[4] & 32) != 0); } unsigned char lodepng_chunk_private(const unsigned char* chunk) { return((chunk[5] & 32) != 0); } /* this is an error if it is reserved: the third character must be uppercase in the PNG standard, lowercasing this character is reserved for possible future extension by the spec*/ static unsigned char lodepng_chunk_reserved(const unsigned char* chunk) { return((chunk[6] & 32) != 0); } unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk) { return((chunk[7] & 32) != 0); } unsigned char* lodepng_chunk_data(unsigned char* chunk) { return &chunk[8]; } const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk) { return &chunk[8]; } unsigned lodepng_chunk_check_crc(const unsigned char* chunk) { unsigned length = lodepng_chunk_length(chunk); unsigned crc = lodepng_read32bitInt(&chunk[length + 8]); /*the CRC is taken of the data and the 4 chunk type letters, not the length*/ unsigned checksum = lodepng_crc32(&chunk[4], length + 4); if(crc != checksum) return 1; else return 0; } void lodepng_chunk_generate_crc(unsigned char* chunk) { unsigned length = lodepng_chunk_length(chunk); unsigned crc = lodepng_crc32(&chunk[4], length + 4); lodepng_set32bitInt(chunk + 8 + length, crc); } unsigned char* lodepng_chunk_next(unsigned char* chunk, unsigned char* end) { size_t available_size = (size_t)(end - chunk); if(chunk >= end || available_size < 12) return end; /*too small to contain a chunk*/ if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47 && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) { /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */ return chunk + 8; } else { size_t total_chunk_length; if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end; if(total_chunk_length > available_size) return end; /*outside of range*/ return chunk + total_chunk_length; } } const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end) { size_t available_size = (size_t)(end - chunk); if(chunk >= end || available_size < 12) return end; /*too small to contain a chunk*/ if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47 && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) { /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */ return chunk + 8; } else { size_t total_chunk_length; if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end; if(total_chunk_length > available_size) return end; /*outside of range*/ return chunk + total_chunk_length; } } unsigned char* lodepng_chunk_find(unsigned char* chunk, unsigned char* end, const char type[5]) { for(;;) { if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */ if(lodepng_chunk_type_equals(chunk, type)) return chunk; chunk = lodepng_chunk_next(chunk, end); } } const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]) { for(;;) { if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */ if(lodepng_chunk_type_equals(chunk, type)) return chunk; chunk = lodepng_chunk_next_const(chunk, end); } } unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk) { unsigned i; size_t total_chunk_length, new_length; unsigned char *chunk_start, *new_buffer; if(!lodepng_chunk_type_name_valid(chunk)) { return 121; /* invalid chunk type name */ } if(lodepng_chunk_reserved(chunk)) { return 122; /* invalid third lowercase character */ } if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return 77; if(lodepng_addofl(*outsize, total_chunk_length, &new_length)) return 77; new_buffer = (unsigned char*)lodepng_realloc(*out, new_length); if(!new_buffer) return 83; /*alloc fail*/ (*out) = new_buffer; (*outsize) = new_length; chunk_start = &(*out)[new_length - total_chunk_length]; for(i = 0; i != total_chunk_length; ++i) chunk_start[i] = chunk[i]; return 0; } /*Sets length and name and allocates the space for data and crc but does not set data or crc yet. Returns the start of the chunk in chunk. The start of the data is at chunk + 8. To finalize chunk, add the data, then use lodepng_chunk_generate_crc */ static unsigned lodepng_chunk_init(unsigned char** chunk, ucvector* out, size_t length, const char* type) { size_t new_length = out->size; if(lodepng_addofl(new_length, length, &new_length)) return 77; if(lodepng_addofl(new_length, 12, &new_length)) return 77; if(!ucvector_resize(out, new_length)) return 83; /*alloc fail*/ *chunk = out->data + new_length - length - 12u; /*1: length*/ lodepng_set32bitInt(*chunk, (unsigned)length); /*2: chunk name (4 letters)*/ lodepng_memcpy(*chunk + 4, type, 4); return 0; } /* like lodepng_chunk_create but with custom allocsize */ static unsigned lodepng_chunk_createv(ucvector* out, size_t length, const char* type, const unsigned char* data) { unsigned char* chunk; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, length, type)); /*3: the data*/ lodepng_memcpy(chunk + 8, data, length); /*4: CRC (of the chunkname characters and the data)*/ lodepng_chunk_generate_crc(chunk); return 0; } unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, size_t length, const char* type, const unsigned char* data) { ucvector v = ucvector_init(*out, *outsize); unsigned error = lodepng_chunk_createv(&v, length, type, data); *out = v.data; *outsize = v.size; return error; } /* ////////////////////////////////////////////////////////////////////////// */ /* / Color types, channels, bits / */ /* ////////////////////////////////////////////////////////////////////////// */ /*checks if the colortype is valid and the bitdepth bd is allowed for this colortype. Return value is a LodePNG error code.*/ static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) { switch(colortype) { case LCT_GREY: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break; case LCT_RGB: if(!( bd == 8 || bd == 16)) return 37; break; case LCT_PALETTE: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 )) return 37; break; case LCT_GREY_ALPHA: if(!( bd == 8 || bd == 16)) return 37; break; case LCT_RGBA: if(!( bd == 8 || bd == 16)) return 37; break; case LCT_MAX_OCTET_VALUE: return 31; /* invalid color type */ default: return 31; /* invalid color type */ } return 0; /*allowed color type / bits combination*/ } static unsigned getNumColorChannels(LodePNGColorType colortype) { switch(colortype) { case LCT_GREY: return 1; case LCT_RGB: return 3; case LCT_PALETTE: return 1; case LCT_GREY_ALPHA: return 2; case LCT_RGBA: return 4; case LCT_MAX_OCTET_VALUE: return 0; /* invalid color type */ default: return 0; /*invalid color type*/ } } static unsigned lodepng_get_bpp_lct(LodePNGColorType colortype, unsigned bitdepth) { /*bits per pixel is amount of channels * bits per channel*/ return getNumColorChannels(colortype) * bitdepth; } /* ////////////////////////////////////////////////////////////////////////// */ void lodepng_color_mode_init(LodePNGColorMode* info) { info->key_defined = 0; info->key_r = info->key_g = info->key_b = 0; info->colortype = LCT_RGBA; info->bitdepth = 8; info->palette = 0; info->palettesize = 0; } /*allocates palette memory if needed, and initializes all colors to black*/ static void lodepng_color_mode_alloc_palette(LodePNGColorMode* info) { size_t i; /*if the palette is already allocated, it will have size 1024 so no reallocation needed in that case*/ /*the palette must have room for up to 256 colors with 4 bytes each.*/ if(!info->palette) info->palette = (unsigned char*)lodepng_malloc(1024); if(!info->palette) return; /*alloc fail*/ for(i = 0; i != 256; ++i) { /*Initialize all unused colors with black, the value used for invalid palette indices. This is an error according to the PNG spec, but common PNG decoders make it black instead. That makes color conversion slightly faster due to no error handling needed.*/ info->palette[i * 4 + 0] = 0; info->palette[i * 4 + 1] = 0; info->palette[i * 4 + 2] = 0; info->palette[i * 4 + 3] = 255; } } void lodepng_color_mode_cleanup(LodePNGColorMode* info) { lodepng_palette_clear(info); } unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source) { lodepng_color_mode_cleanup(dest); lodepng_memcpy(dest, source, sizeof(LodePNGColorMode)); if(source->palette) { dest->palette = (unsigned char*)lodepng_malloc(1024); if(!dest->palette && source->palettesize) return 83; /*alloc fail*/ lodepng_memcpy(dest->palette, source->palette, source->palettesize * 4); } return 0; } LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth) { LodePNGColorMode result; lodepng_color_mode_init(&result); result.colortype = colortype; result.bitdepth = bitdepth; return result; } static int lodepng_color_mode_equal(const LodePNGColorMode* a, const LodePNGColorMode* b) { size_t i; if(a->colortype != b->colortype) return 0; if(a->bitdepth != b->bitdepth) return 0; if(a->key_defined != b->key_defined) return 0; if(a->key_defined) { if(a->key_r != b->key_r) return 0; if(a->key_g != b->key_g) return 0; if(a->key_b != b->key_b) return 0; } if(a->palettesize != b->palettesize) return 0; for(i = 0; i != a->palettesize * 4; ++i) { if(a->palette[i] != b->palette[i]) return 0; } return 1; } void lodepng_palette_clear(LodePNGColorMode* info) { if(info->palette) lodepng_free(info->palette); info->palette = 0; info->palettesize = 0; } unsigned lodepng_palette_add(LodePNGColorMode* info, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { if(!info->palette) /*allocate palette if empty*/ { lodepng_color_mode_alloc_palette(info); if(!info->palette) return 83; /*alloc fail*/ } if(info->palettesize >= 256) { return 108; /*too many palette values*/ } info->palette[4 * info->palettesize + 0] = r; info->palette[4 * info->palettesize + 1] = g; info->palette[4 * info->palettesize + 2] = b; info->palette[4 * info->palettesize + 3] = a; ++info->palettesize; return 0; } /*calculate bits per pixel out of colortype and bitdepth*/ unsigned lodepng_get_bpp(const LodePNGColorMode* info) { return lodepng_get_bpp_lct(info->colortype, info->bitdepth); } unsigned lodepng_get_channels(const LodePNGColorMode* info) { return getNumColorChannels(info->colortype); } unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info) { return info->colortype == LCT_GREY || info->colortype == LCT_GREY_ALPHA; } unsigned lodepng_is_alpha_type(const LodePNGColorMode* info) { return (info->colortype & 4) != 0; /*4 or 6*/ } unsigned lodepng_is_palette_type(const LodePNGColorMode* info) { return info->colortype == LCT_PALETTE; } unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info) { size_t i; for(i = 0; i != info->palettesize; ++i) { if(info->palette[i * 4 + 3] < 255) return 1; } return 0; } unsigned lodepng_can_have_alpha(const LodePNGColorMode* info) { return info->key_defined || lodepng_is_alpha_type(info) || lodepng_has_palette_alpha(info); } static size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { size_t bpp = lodepng_get_bpp_lct(colortype, bitdepth); size_t n = (size_t)w * (size_t)h; return ((n / 8u) * bpp) + ((n & 7u) * bpp + 7u) / 8u; } size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color) { return lodepng_get_raw_size_lct(w, h, color->colortype, color->bitdepth); } #ifdef LODEPNG_COMPILE_PNG /*in an idat chunk, each scanline is a multiple of 8 bits, unlike the lodepng output buffer, and in addition has one extra byte per line: the filter byte. So this gives a larger result than lodepng_get_raw_size. Set h to 1 to get the size of 1 row including filter byte. */ static size_t lodepng_get_raw_size_idat(unsigned w, unsigned h, unsigned bpp) { /* + 1 for the filter byte, and possibly plus padding bits per line. */ /* Ignoring casts, the expression is equal to (w * bpp + 7) / 8 + 1, but avoids overflow of w * bpp */ size_t line = ((size_t)(w / 8u) * bpp) + 1u + ((w & 7u) * bpp + 7u) / 8u; return (size_t)h * line; } #ifdef LODEPNG_COMPILE_DECODER /*Safely checks whether size_t overflow can be caused due to amount of pixels. This check is overcautious rather than precise. If this check indicates no overflow, you can safely compute in a size_t (but not an unsigned): -(size_t)w * (size_t)h * 8 -amount of bytes in IDAT (including filter, padding and Adam7 bytes) -amount of bytes in raw color model Returns 1 if overflow possible, 0 if not. */ static int lodepng_pixel_overflow(unsigned w, unsigned h, const LodePNGColorMode* pngcolor, const LodePNGColorMode* rawcolor) { size_t bpp = LODEPNG_MAX(lodepng_get_bpp(pngcolor), lodepng_get_bpp(rawcolor)); size_t numpixels, total; size_t line; /* bytes per line in worst case */ if(lodepng_mulofl((size_t)w, (size_t)h, &numpixels)) return 1; if(lodepng_mulofl(numpixels, 8, &total)) return 1; /* bit pointer with 8-bit color, or 8 bytes per channel color */ /* Bytes per scanline with the expression "(w / 8u) * bpp) + ((w & 7u) * bpp + 7u) / 8u" */ if(lodepng_mulofl((size_t)(w / 8u), bpp, &line)) return 1; if(lodepng_addofl(line, ((w & 7u) * bpp + 7u) / 8u, &line)) return 1; if(lodepng_addofl(line, 5, &line)) return 1; /* 5 bytes overhead per line: 1 filterbyte, 4 for Adam7 worst case */ if(lodepng_mulofl(line, h, &total)) return 1; /* Total bytes in worst case */ return 0; /* no overflow */ } #endif /*LODEPNG_COMPILE_DECODER*/ #endif /*LODEPNG_COMPILE_PNG*/ #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS static void LodePNGUnknownChunks_init(LodePNGInfo* info) { unsigned i; for(i = 0; i != 3; ++i) info->unknown_chunks_data[i] = 0; for(i = 0; i != 3; ++i) info->unknown_chunks_size[i] = 0; } static void LodePNGUnknownChunks_cleanup(LodePNGInfo* info) { unsigned i; for(i = 0; i != 3; ++i) lodepng_free(info->unknown_chunks_data[i]); } static unsigned LodePNGUnknownChunks_copy(LodePNGInfo* dest, const LodePNGInfo* src) { unsigned i; LodePNGUnknownChunks_cleanup(dest); for(i = 0; i != 3; ++i) { size_t j; dest->unknown_chunks_size[i] = src->unknown_chunks_size[i]; dest->unknown_chunks_data[i] = (unsigned char*)lodepng_malloc(src->unknown_chunks_size[i]); if(!dest->unknown_chunks_data[i] && dest->unknown_chunks_size[i]) return 83; /*alloc fail*/ for(j = 0; j < src->unknown_chunks_size[i]; ++j) { dest->unknown_chunks_data[i][j] = src->unknown_chunks_data[i][j]; } } return 0; } /******************************************************************************/ static void LodePNGText_init(LodePNGInfo* info) { info->text_num = 0; info->text_keys = NULL; info->text_strings = NULL; } static void LodePNGText_cleanup(LodePNGInfo* info) { size_t i; for(i = 0; i != info->text_num; ++i) { lodepng_free(info->text_keys[i]); lodepng_free(info->text_strings[i]); } lodepng_free(info->text_keys); lodepng_free(info->text_strings); } static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source) { size_t i = 0; dest->text_keys = NULL; dest->text_strings = NULL; dest->text_num = 0; for(i = 0; i != source->text_num; ++i) { CERROR_TRY_RETURN(lodepng_add_text(dest, source->text_keys[i], source->text_strings[i])); } return 0; } static unsigned lodepng_add_text_sized(LodePNGInfo* info, const char* key, const char* str, size_t size) { char** new_keys = (char**)(lodepng_realloc(info->text_keys, sizeof(char*) * (info->text_num + 1))); char** new_strings = (char**)(lodepng_realloc(info->text_strings, sizeof(char*) * (info->text_num + 1))); if(new_keys) info->text_keys = new_keys; if(new_strings) info->text_strings = new_strings; if(!new_keys || !new_strings) return 83; /*alloc fail*/ ++info->text_num; info->text_keys[info->text_num - 1] = alloc_string(key); info->text_strings[info->text_num - 1] = alloc_string_sized(str, size); if(!info->text_keys[info->text_num - 1] || !info->text_strings[info->text_num - 1]) return 83; /*alloc fail*/ return 0; } unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str) { return lodepng_add_text_sized(info, key, str, lodepng_strlen(str)); } void lodepng_clear_text(LodePNGInfo* info) { LodePNGText_cleanup(info); /*cleanup only deconstructs, need to init again to set appropriate pointers to NULL*/ LodePNGText_init(info); } /******************************************************************************/ static void LodePNGIText_init(LodePNGInfo* info) { info->itext_num = 0; info->itext_keys = NULL; info->itext_langtags = NULL; info->itext_transkeys = NULL; info->itext_strings = NULL; } static void LodePNGIText_cleanup(LodePNGInfo* info) { size_t i; for(i = 0; i != info->itext_num; ++i) { lodepng_free(info->itext_keys[i]); lodepng_free(info->itext_langtags[i]); lodepng_free(info->itext_transkeys[i]); lodepng_free(info->itext_strings[i]); } lodepng_free(info->itext_keys); lodepng_free(info->itext_langtags); lodepng_free(info->itext_transkeys); lodepng_free(info->itext_strings); } static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source) { size_t i = 0; dest->itext_keys = NULL; dest->itext_langtags = NULL; dest->itext_transkeys = NULL; dest->itext_strings = NULL; dest->itext_num = 0; for(i = 0; i != source->itext_num; ++i) { CERROR_TRY_RETURN(lodepng_add_itext(dest, source->itext_keys[i], source->itext_langtags[i], source->itext_transkeys[i], source->itext_strings[i])); } return 0; } void lodepng_clear_itext(LodePNGInfo* info) { LodePNGIText_cleanup(info); /*cleanup only deconstructs, need to init again to set appropriate pointers to NULL*/ LodePNGIText_init(info); } static unsigned lodepng_add_itext_sized(LodePNGInfo* info, const char* key, const char* langtag, const char* transkey, const char* str, size_t size) { char** new_keys = (char**)(lodepng_realloc(info->itext_keys, sizeof(char*) * (info->itext_num + 1))); char** new_langtags = (char**)(lodepng_realloc(info->itext_langtags, sizeof(char*) * (info->itext_num + 1))); char** new_transkeys = (char**)(lodepng_realloc(info->itext_transkeys, sizeof(char*) * (info->itext_num + 1))); char** new_strings = (char**)(lodepng_realloc(info->itext_strings, sizeof(char*) * (info->itext_num + 1))); if(new_keys) info->itext_keys = new_keys; if(new_langtags) info->itext_langtags = new_langtags; if(new_transkeys) info->itext_transkeys = new_transkeys; if(new_strings) info->itext_strings = new_strings; if(!new_keys || !new_langtags || !new_transkeys || !new_strings) return 83; /*alloc fail*/ ++info->itext_num; info->itext_keys[info->itext_num - 1] = alloc_string(key); info->itext_langtags[info->itext_num - 1] = alloc_string(langtag); info->itext_transkeys[info->itext_num - 1] = alloc_string(transkey); info->itext_strings[info->itext_num - 1] = alloc_string_sized(str, size); return 0; } unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag, const char* transkey, const char* str) { return lodepng_add_itext_sized(info, key, langtag, transkey, str, lodepng_strlen(str)); } unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) { if(info->iccp_defined) lodepng_clear_icc(info); if(profile_size == 0) return 123; /*invalid ICC profile size*/ info->iccp_name = alloc_string(name); if(!info->iccp_name) return 83; /*alloc fail*/ info->iccp_profile = (unsigned char*)lodepng_malloc(profile_size); if(!info->iccp_profile) { lodepng_free(info->iccp_name); return 83; /*alloc fail*/ } lodepng_memcpy(info->iccp_profile, profile, profile_size); info->iccp_profile_size = profile_size; info->iccp_defined = 1; return 0; /*ok*/ } static void lodepng_init_icc(LodePNGInfo* info) { info->iccp_defined = 0; info->iccp_name = NULL; info->iccp_profile = NULL; info->iccp_profile_size = 0; } void lodepng_clear_icc(LodePNGInfo* info) { lodepng_free(info->iccp_name); lodepng_free(info->iccp_profile); lodepng_init_icc(info); } unsigned lodepng_set_exif(LodePNGInfo* info, const unsigned char* exif, unsigned exif_size) { if(info->exif_defined) lodepng_clear_exif(info); info->exif = (unsigned char*)lodepng_malloc(exif_size); if(!info->exif) return 83; /*alloc fail*/ lodepng_memcpy(info->exif, exif, exif_size); info->exif_size = exif_size; info->exif_defined = 1; return 0; /*ok*/ } static void lodepng_init_exif(LodePNGInfo* info) { info->exif_defined = 0; info->exif = NULL; info->exif_size = 0; } void lodepng_clear_exif(LodePNGInfo* info) { lodepng_free(info->exif); lodepng_init_exif(info); } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ void lodepng_info_init(LodePNGInfo* info) { lodepng_color_mode_init(&info->color); info->interlace_method = 0; info->compression_method = 0; info->filter_method = 0; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS info->background_defined = 0; info->background_r = info->background_g = info->background_b = 0; LodePNGText_init(info); LodePNGIText_init(info); lodepng_init_icc(info); lodepng_init_exif(info); info->time_defined = 0; info->phys_defined = 0; info->gama_defined = 0; info->chrm_defined = 0; info->srgb_defined = 0; info->cicp_defined = 0; info->cicp_color_primaries = 0; info->cicp_transfer_function = 0; info->cicp_matrix_coefficients = 0; info->cicp_video_full_range_flag = 0; info->mdcv_defined = 0; info->mdcv_red_x = 0; info->mdcv_red_y = 0; info->mdcv_green_x = 0; info->mdcv_green_y = 0; info->mdcv_blue_x = 0; info->mdcv_blue_y = 0; info->mdcv_white_x = 0; info->mdcv_white_y = 0; info->mdcv_max_luminance = 0; info->mdcv_min_luminance = 0; info->clli_defined = 0; info->clli_max_cll = 0; info->clli_max_fall = 0; info->sbit_defined = 0; info->sbit_r = info->sbit_g = info->sbit_b = info->sbit_a = 0; LodePNGUnknownChunks_init(info); #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } void lodepng_info_cleanup(LodePNGInfo* info) { lodepng_color_mode_cleanup(&info->color); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS LodePNGText_cleanup(info); LodePNGIText_cleanup(info); lodepng_clear_icc(info); lodepng_clear_exif(info); LodePNGUnknownChunks_cleanup(info); #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source) { lodepng_info_cleanup(dest); lodepng_memcpy(dest, source, sizeof(LodePNGInfo)); /*ensure to initialize all fields pointing to allocated data to NULL first*/ lodepng_color_mode_init(&dest->color); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS LodePNGText_init(dest); LodePNGIText_init(dest); lodepng_init_icc(dest); lodepng_init_exif(dest); LodePNGUnknownChunks_init(dest); #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ CERROR_TRY_RETURN(lodepng_color_mode_copy(&dest->color, &source->color)); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS CERROR_TRY_RETURN(LodePNGText_copy(dest, source)); CERROR_TRY_RETURN(LodePNGIText_copy(dest, source)); if(source->iccp_defined) { CERROR_TRY_RETURN(lodepng_set_icc(dest, source->iccp_name, source->iccp_profile, source->iccp_profile_size)); } if(source->exif_defined) { CERROR_TRY_RETURN(lodepng_set_exif(dest, source->exif, source->exif_size)); } CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source)); #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ return 0; } /* ////////////////////////////////////////////////////////////////////////// */ /*index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to*/ static void addColorBits(unsigned char* out, size_t index, unsigned bits, unsigned in) { unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/ /*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/ unsigned p = index & m; in &= (1u << bits) - 1u; /*filter out any other bits of the input value*/ in = in << (bits * (m - p)); if(p == 0) out[index * bits / 8u] = in; else out[index * bits / 8u] |= in; } typedef struct ColorTree ColorTree; /* One node of a color tree This is the data structure used to count the number of unique colors and to get a palette index for a color. It's like an octree, but because the alpha channel is used too, each node has 16 instead of 8 children. */ struct ColorTree { ColorTree* children[16]; /*up to 16 pointers to ColorTree of next level*/ int index; /*the payload. Only has a meaningful value if this is in the last level*/ }; static void color_tree_init(ColorTree* tree) { lodepng_memset(tree->children, 0, 16 * sizeof(*tree->children)); tree->index = -1; } static void color_tree_cleanup(ColorTree* tree) { int i; for(i = 0; i != 16; ++i) { if(tree->children[i]) { color_tree_cleanup(tree->children[i]); lodepng_free(tree->children[i]); } } } /*returns -1 if color not present, its index otherwise*/ static int color_tree_get(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { int bit = 0; for(bit = 0; bit < 8; ++bit) { int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1); if(!tree->children[i]) return -1; else tree = tree->children[i]; } return tree ? tree->index : -1; } #ifdef LODEPNG_COMPILE_ENCODER static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { return color_tree_get(tree, r, g, b, a) >= 0; } #endif /*LODEPNG_COMPILE_ENCODER*/ /*color is not allowed to already exist. Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist") Returns error code, or 0 if ok*/ static unsigned color_tree_add(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a, unsigned index) { int bit; for(bit = 0; bit < 8; ++bit) { int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1); if(!tree->children[i]) { tree->children[i] = (ColorTree*)lodepng_malloc(sizeof(ColorTree)); if(!tree->children[i]) return 83; /*alloc fail*/ color_tree_init(tree->children[i]); } tree = tree->children[i]; } tree->index = (int)index; return 0; } /*put a pixel, given its RGBA color, into image of any color type*/ static unsigned rgba8ToPixel(unsigned char* out, size_t i, const LodePNGColorMode* mode, ColorTree* tree /*for palette*/, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { if(mode->colortype == LCT_GREY) { unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/ if(mode->bitdepth == 8) out[i] = gray; else if(mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = gray; else { /*take the most significant bits of gray*/ gray = ((unsigned)gray >> (8u - mode->bitdepth)) & ((1u << mode->bitdepth) - 1u); addColorBits(out, i, mode->bitdepth, gray); } } else if(mode->colortype == LCT_RGB) { if(mode->bitdepth == 8) { out[i * 3 + 0] = r; out[i * 3 + 1] = g; out[i * 3 + 2] = b; } else { out[i * 6 + 0] = out[i * 6 + 1] = r; out[i * 6 + 2] = out[i * 6 + 3] = g; out[i * 6 + 4] = out[i * 6 + 5] = b; } } else if(mode->colortype == LCT_PALETTE) { int index = color_tree_get(tree, r, g, b, a); if(index < 0) return 82; /*color not in palette*/ if(mode->bitdepth == 8) out[i] = index; else addColorBits(out, i, mode->bitdepth, (unsigned)index); } else if(mode->colortype == LCT_GREY_ALPHA) { unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/ if(mode->bitdepth == 8) { out[i * 2 + 0] = gray; out[i * 2 + 1] = a; } else if(mode->bitdepth == 16) { out[i * 4 + 0] = out[i * 4 + 1] = gray; out[i * 4 + 2] = out[i * 4 + 3] = a; } } else if(mode->colortype == LCT_RGBA) { if(mode->bitdepth == 8) { out[i * 4 + 0] = r; out[i * 4 + 1] = g; out[i * 4 + 2] = b; out[i * 4 + 3] = a; } else { out[i * 8 + 0] = out[i * 8 + 1] = r; out[i * 8 + 2] = out[i * 8 + 3] = g; out[i * 8 + 4] = out[i * 8 + 5] = b; out[i * 8 + 6] = out[i * 8 + 7] = a; } } return 0; /*no error*/ } /*put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type*/ static void rgba16ToPixel(unsigned char* out, size_t i, const LodePNGColorMode* mode, unsigned short r, unsigned short g, unsigned short b, unsigned short a) { if(mode->colortype == LCT_GREY) { unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/ out[i * 2 + 0] = (gray >> 8) & 255; out[i * 2 + 1] = gray & 255; } else if(mode->colortype == LCT_RGB) { out[i * 6 + 0] = (r >> 8) & 255; out[i * 6 + 1] = r & 255; out[i * 6 + 2] = (g >> 8) & 255; out[i * 6 + 3] = g & 255; out[i * 6 + 4] = (b >> 8) & 255; out[i * 6 + 5] = b & 255; } else if(mode->colortype == LCT_GREY_ALPHA) { unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/ out[i * 4 + 0] = (gray >> 8) & 255; out[i * 4 + 1] = gray & 255; out[i * 4 + 2] = (a >> 8) & 255; out[i * 4 + 3] = a & 255; } else if(mode->colortype == LCT_RGBA) { out[i * 8 + 0] = (r >> 8) & 255; out[i * 8 + 1] = r & 255; out[i * 8 + 2] = (g >> 8) & 255; out[i * 8 + 3] = g & 255; out[i * 8 + 4] = (b >> 8) & 255; out[i * 8 + 5] = b & 255; out[i * 8 + 6] = (a >> 8) & 255; out[i * 8 + 7] = a & 255; } } /*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/ static void getPixelColorRGBA8(unsigned char* r, unsigned char* g, unsigned char* b, unsigned char* a, const unsigned char* in, size_t i, const LodePNGColorMode* mode) { if(mode->colortype == LCT_GREY) { if(mode->bitdepth == 8) { *r = *g = *b = in[i]; if(mode->key_defined && *r == mode->key_r) *a = 0; else *a = 255; } else if(mode->bitdepth == 16) { *r = *g = *b = in[i * 2 + 0]; if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; else *a = 255; } else { unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ size_t j = i * mode->bitdepth; unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); *r = *g = *b = (value * 255) / highest; if(mode->key_defined && value == mode->key_r) *a = 0; else *a = 255; } } else if(mode->colortype == LCT_RGB) { if(mode->bitdepth == 8) { *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2]; if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0; else *a = 255; } else { *r = in[i * 6 + 0]; *g = in[i * 6 + 2]; *b = in[i * 6 + 4]; if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; else *a = 255; } } else if(mode->colortype == LCT_PALETTE) { unsigned index; if(mode->bitdepth == 8) index = in[i]; else { size_t j = i * mode->bitdepth; index = readBitsFromReversedStream(&j, in, mode->bitdepth); } /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ *r = mode->palette[index * 4 + 0]; *g = mode->palette[index * 4 + 1]; *b = mode->palette[index * 4 + 2]; *a = mode->palette[index * 4 + 3]; } else if(mode->colortype == LCT_GREY_ALPHA) { if(mode->bitdepth == 8) { *r = *g = *b = in[i * 2 + 0]; *a = in[i * 2 + 1]; } else { *r = *g = *b = in[i * 4 + 0]; *a = in[i * 4 + 2]; } } else if(mode->colortype == LCT_RGBA) { if(mode->bitdepth == 8) { *r = in[i * 4 + 0]; *g = in[i * 4 + 1]; *b = in[i * 4 + 2]; *a = in[i * 4 + 3]; } else { *r = in[i * 8 + 0]; *g = in[i * 8 + 2]; *b = in[i * 8 + 4]; *a = in[i * 8 + 6]; } } } /*Similar to getPixelColorRGBA8, but with all the for loops inside of the color mode test cases, optimized to convert the colors much faster, when converting to the common case of RGBA with 8 bit per channel. buffer must be RGBA with enough memory.*/ static void getPixelColorsRGBA8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels, const unsigned char* LODEPNG_RESTRICT in, const LodePNGColorMode* mode) { unsigned num_channels = 4; size_t i; if(mode->colortype == LCT_GREY) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i]; buffer[3] = 255; } if(mode->key_defined) { buffer -= numpixels * num_channels; for(i = 0; i != numpixels; ++i, buffer += num_channels) { if(buffer[0] == mode->key_r) buffer[3] = 0; } } } else if(mode->bitdepth == 16) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i * 2]; buffer[3] = mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r ? 0 : 255; } } else { unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ size_t j = 0; for(i = 0; i != numpixels; ++i, buffer += num_channels) { unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest; buffer[3] = mode->key_defined && value == mode->key_r ? 0 : 255; } } } else if(mode->colortype == LCT_RGB) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { lodepng_memcpy(buffer, &in[i * 3], 3); buffer[3] = 255; } if(mode->key_defined) { buffer -= numpixels * num_channels; for(i = 0; i != numpixels; ++i, buffer += num_channels) { if(buffer[0] == mode->key_r && buffer[1]== mode->key_g && buffer[2] == mode->key_b) buffer[3] = 0; } } } else { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = in[i * 6 + 0]; buffer[1] = in[i * 6 + 2]; buffer[2] = in[i * 6 + 4]; buffer[3] = mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b ? 0 : 255; } } } else if(mode->colortype == LCT_PALETTE) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { unsigned index = in[i]; /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ lodepng_memcpy(buffer, &mode->palette[index * 4], 4); } } else { size_t j = 0; for(i = 0; i != numpixels; ++i, buffer += num_channels) { unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth); /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ lodepng_memcpy(buffer, &mode->palette[index * 4], 4); } } } else if(mode->colortype == LCT_GREY_ALPHA) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0]; buffer[3] = in[i * 2 + 1]; } } else { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0]; buffer[3] = in[i * 4 + 2]; } } } else if(mode->colortype == LCT_RGBA) { if(mode->bitdepth == 8) { lodepng_memcpy(buffer, in, numpixels * 4); } else { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = in[i * 8 + 0]; buffer[1] = in[i * 8 + 2]; buffer[2] = in[i * 8 + 4]; buffer[3] = in[i * 8 + 6]; } } } } /*Similar to getPixelColorsRGBA8, but with 3-channel RGB output.*/ static void getPixelColorsRGB8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels, const unsigned char* LODEPNG_RESTRICT in, const LodePNGColorMode* mode) { const unsigned num_channels = 3; size_t i; if(mode->colortype == LCT_GREY) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i]; } } else if(mode->bitdepth == 16) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i * 2]; } } else { unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ size_t j = 0; for(i = 0; i != numpixels; ++i, buffer += num_channels) { unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest; } } } else if(mode->colortype == LCT_RGB) { if(mode->bitdepth == 8) { lodepng_memcpy(buffer, in, numpixels * 3); } else { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = in[i * 6 + 0]; buffer[1] = in[i * 6 + 2]; buffer[2] = in[i * 6 + 4]; } } } else if(mode->colortype == LCT_PALETTE) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { unsigned index = in[i]; /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ lodepng_memcpy(buffer, &mode->palette[index * 4], 3); } } else { size_t j = 0; for(i = 0; i != numpixels; ++i, buffer += num_channels) { unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth); /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ lodepng_memcpy(buffer, &mode->palette[index * 4], 3); } } } else if(mode->colortype == LCT_GREY_ALPHA) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0]; } } else { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0]; } } } else if(mode->colortype == LCT_RGBA) { if(mode->bitdepth == 8) { for(i = 0; i != numpixels; ++i, buffer += num_channels) { lodepng_memcpy(buffer, &in[i * 4], 3); } } else { for(i = 0; i != numpixels; ++i, buffer += num_channels) { buffer[0] = in[i * 8 + 0]; buffer[1] = in[i * 8 + 2]; buffer[2] = in[i * 8 + 4]; } } } } /*Get RGBA16 color of pixel with index i (y * width + x) from the raw image with given color type, but the given color type must be 16-bit itself.*/ static void getPixelColorRGBA16(unsigned short* r, unsigned short* g, unsigned short* b, unsigned short* a, const unsigned char* in, size_t i, const LodePNGColorMode* mode) { if(mode->colortype == LCT_GREY) { *r = *g = *b = 256 * in[i * 2 + 0] + in[i * 2 + 1]; if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; else *a = 65535; } else if(mode->colortype == LCT_RGB) { *r = 256u * in[i * 6 + 0] + in[i * 6 + 1]; *g = 256u * in[i * 6 + 2] + in[i * 6 + 3]; *b = 256u * in[i * 6 + 4] + in[i * 6 + 5]; if(mode->key_defined && 256u * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r && 256u * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g && 256u * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; else *a = 65535; } else if(mode->colortype == LCT_GREY_ALPHA) { *r = *g = *b = 256u * in[i * 4 + 0] + in[i * 4 + 1]; *a = 256u * in[i * 4 + 2] + in[i * 4 + 3]; } else if(mode->colortype == LCT_RGBA) { *r = 256u * in[i * 8 + 0] + in[i * 8 + 1]; *g = 256u * in[i * 8 + 2] + in[i * 8 + 3]; *b = 256u * in[i * 8 + 4] + in[i * 8 + 5]; *a = 256u * in[i * 8 + 6] + in[i * 8 + 7]; } } unsigned lodepng_convert(unsigned char* out, const unsigned char* in, const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, unsigned w, unsigned h) { size_t i; ColorTree tree; size_t numpixels = (size_t)w * (size_t)h; unsigned error = 0; if(mode_in->colortype == LCT_PALETTE && !mode_in->palette) { return 107; /* error: must provide palette if input mode is palette */ } if(lodepng_color_mode_equal(mode_out, mode_in)) { size_t numbytes = lodepng_get_raw_size(w, h, mode_in); lodepng_memcpy(out, in, numbytes); return 0; } if(mode_out->colortype == LCT_PALETTE) { size_t palettesize = mode_out->palettesize; const unsigned char* palette = mode_out->palette; size_t palsize = (size_t)1u << mode_out->bitdepth; /*if the user specified output palette but did not give the values, assume they want the values of the input color type (assuming that one is palette). Note that we never create a new palette ourselves.*/ if(palettesize == 0) { palettesize = mode_in->palettesize; palette = mode_in->palette; /*if the input was also palette with same bitdepth, then the color types are also equal, so copy literally. This to preserve the exact indices that were in the PNG even in case there are duplicate colors in the palette.*/ if(mode_in->colortype == LCT_PALETTE && mode_in->bitdepth == mode_out->bitdepth) { size_t numbytes = lodepng_get_raw_size(w, h, mode_in); lodepng_memcpy(out, in, numbytes); return 0; } } if(palettesize < palsize) palsize = palettesize; color_tree_init(&tree); for(i = 0; i != palsize; ++i) { const unsigned char* p = &palette[i * 4]; error = color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned)i); if(error) break; } } if(!error) { if(mode_in->bitdepth == 16 && mode_out->bitdepth == 16) { for(i = 0; i != numpixels; ++i) { unsigned short r = 0, g = 0, b = 0, a = 0; getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); rgba16ToPixel(out, i, mode_out, r, g, b, a); } } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGBA) { getPixelColorsRGBA8(out, numpixels, in, mode_in); } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGB) { getPixelColorsRGB8(out, numpixels, in, mode_in); } else { unsigned char r = 0, g = 0, b = 0, a = 0; for(i = 0; i != numpixels; ++i) { getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a); if(error) break; } } } if(mode_out->colortype == LCT_PALETTE) { color_tree_cleanup(&tree); } return error; } /* Converts a single rgb color without alpha from one type to another, color bits truncated to their bitdepth. In case of single channel (gray or palette), only the r channel is used. Slow function, do not use to process all pixels of an image. Alpha channel not supported on purpose: this is for bKGD, supporting alpha may prevent it from finding a color in the palette, from the specification it looks like bKGD should ignore the alpha values of the palette since it can use any palette index but doesn't have an alpha channel. Idem with ignoring color key. */ unsigned lodepng_convert_rgb( unsigned* r_out, unsigned* g_out, unsigned* b_out, unsigned r_in, unsigned g_in, unsigned b_in, const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in) { unsigned r = 0, g = 0, b = 0; unsigned mul = 65535 / ((1u << mode_in->bitdepth) - 1u); /*65535, 21845, 4369, 257, 1*/ unsigned shift = 16 - mode_out->bitdepth; if(mode_in->colortype == LCT_GREY || mode_in->colortype == LCT_GREY_ALPHA) { r = g = b = r_in * mul; } else if(mode_in->colortype == LCT_RGB || mode_in->colortype == LCT_RGBA) { r = r_in * mul; g = g_in * mul; b = b_in * mul; } else if(mode_in->colortype == LCT_PALETTE) { if(r_in >= mode_in->palettesize) return 82; r = mode_in->palette[r_in * 4 + 0] * 257u; g = mode_in->palette[r_in * 4 + 1] * 257u; b = mode_in->palette[r_in * 4 + 2] * 257u; } else { return 31; } /* now convert to output format */ if(mode_out->colortype == LCT_GREY || mode_out->colortype == LCT_GREY_ALPHA) { *r_out = r >> shift ; } else if(mode_out->colortype == LCT_RGB || mode_out->colortype == LCT_RGBA) { *r_out = r >> shift ; *g_out = g >> shift ; *b_out = b >> shift ; } else if(mode_out->colortype == LCT_PALETTE) { unsigned i; /* a 16-bit color cannot be in the palette */ if((r >> 8) != (r & 255) || (g >> 8) != (g & 255) || (b >> 8) != (b & 255)) return 82; for(i = 0; i < mode_out->palettesize; i++) { unsigned j = i * 4; if((r >> 8) == mode_out->palette[j + 0] && (g >> 8) == mode_out->palette[j + 1] && (b >> 8) == mode_out->palette[j + 2]) { *r_out = i; return 0; } } return 82; } else { return 31; } return 0; } #ifdef LODEPNG_COMPILE_ENCODER void lodepng_color_stats_init(LodePNGColorStats* stats) { /*stats*/ stats->colored = 0; stats->key = 0; stats->key_r = stats->key_g = stats->key_b = 0; stats->alpha = 0; stats->numcolors = 0; stats->bits = 1; stats->numpixels = 0; /*settings*/ stats->allow_palette = 1; stats->allow_greyscale = 1; } /*function used for debug purposes with C++*/ /*void printColorStats(LodePNGColorStats* p) { std::cout << "colored: " << (int)p->colored << ", "; std::cout << "key: " << (int)p->key << ", "; std::cout << "key_r: " << (int)p->key_r << ", "; std::cout << "key_g: " << (int)p->key_g << ", "; std::cout << "key_b: " << (int)p->key_b << ", "; std::cout << "alpha: " << (int)p->alpha << ", "; std::cout << "numcolors: " << (int)p->numcolors << ", "; std::cout << "bits: " << (int)p->bits << std::endl; }*/ /*Returns how many bits needed to represent given value (max 8 bit)*/ static unsigned getValueRequiredBits(unsigned char value) { if(value == 0 || value == 255) return 1; /*The scaling of 2-bit and 4-bit values uses multiples of 85 and 17*/ if(value % 17 == 0) return value % 85 == 0 ? 2 : 4; return 8; } /*stats must already have been inited. */ unsigned lodepng_compute_color_stats(LodePNGColorStats* stats, const unsigned char* in, unsigned w, unsigned h, const LodePNGColorMode* mode_in) { size_t i; ColorTree tree; size_t numpixels = (size_t)w * (size_t)h; unsigned error = 0; /* mark things as done already if it would be impossible to have a more expensive case */ unsigned colored_done = lodepng_is_greyscale_type(mode_in) ? 1 : 0; unsigned alpha_done = lodepng_can_have_alpha(mode_in) ? 0 : 1; unsigned numcolors_done = 0; unsigned bpp = lodepng_get_bpp(mode_in); unsigned bits_done = (stats->bits == 1 && bpp == 1) ? 1 : 0; unsigned sixteen = 0; /* whether the input image is 16 bit */ unsigned maxnumcolors = 257; if(bpp <= 8) maxnumcolors = LODEPNG_MIN(257, stats->numcolors + (1u << bpp)); stats->numpixels += numpixels; /*if palette not allowed, no need to compute numcolors*/ if(!stats->allow_palette) numcolors_done = 1; color_tree_init(&tree); /*If the stats was already filled in from previous data, fill its palette in tree and mark things as done already if we know they are the most expensive case already*/ if(stats->alpha) alpha_done = 1; if(stats->colored) colored_done = 1; if(stats->bits == 16) numcolors_done = 1; if(stats->bits >= bpp) bits_done = 1; if(stats->numcolors >= maxnumcolors) numcolors_done = 1; if(!numcolors_done) { for(i = 0; i < stats->numcolors; i++) { const unsigned char* color = &stats->palette[i * 4]; error = color_tree_add(&tree, color[0], color[1], color[2], color[3], (unsigned)i); if(error) goto cleanup; } } /*Check if the 16-bit input is truly 16-bit*/ if(mode_in->bitdepth == 16 && !sixteen) { unsigned short r = 0, g = 0, b = 0, a = 0; for(i = 0; i != numpixels; ++i) { getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); if((r & 255) != ((r >> 8) & 255) || (g & 255) != ((g >> 8) & 255) || (b & 255) != ((b >> 8) & 255) || (a & 255) != ((a >> 8) & 255)) /*first and second byte differ*/ { stats->bits = 16; sixteen = 1; bits_done = 1; numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/ break; } } } if(sixteen) { unsigned short r = 0, g = 0, b = 0, a = 0; for(i = 0; i != numpixels; ++i) { getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); if(!colored_done && (r != g || r != b)) { stats->colored = 1; colored_done = 1; } if(!alpha_done) { unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b); if(a != 65535 && (a != 0 || (stats->key && !matchkey))) { stats->alpha = 1; stats->key = 0; alpha_done = 1; } else if(a == 0 && !stats->alpha && !stats->key) { stats->key = 1; stats->key_r = r; stats->key_g = g; stats->key_b = b; } else if(a == 65535 && stats->key && matchkey) { /* Color key cannot be used if an opaque pixel also has that RGB color. */ stats->alpha = 1; stats->key = 0; alpha_done = 1; } } if(alpha_done && numcolors_done && colored_done && bits_done) break; } if(stats->key && !stats->alpha) { for(i = 0; i != numpixels; ++i) { getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) { /* Color key cannot be used if an opaque pixel also has that RGB color. */ stats->alpha = 1; stats->key = 0; alpha_done = 1; } } } } else /* < 16-bit */ { unsigned char r = 0, g = 0, b = 0, a = 0; unsigned char pr = 0, pg = 0, pb = 0, pa = 0; for(i = 0; i != numpixels; ++i) { getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); /*skip if color same as before, this speeds up large non-photographic images with many same colors by avoiding 'color_tree_has' below */ if(i != 0 && r == pr && g == pg && b == pb && a == pa) continue; pr = r; pg = g; pb = b; pa = a; if(!bits_done && stats->bits < 8) { /*only r is checked, < 8 bits is only relevant for grayscale*/ unsigned bits = getValueRequiredBits(r); if(bits > stats->bits) stats->bits = bits; } bits_done = (stats->bits >= bpp); if(!colored_done && (r != g || r != b)) { stats->colored = 1; colored_done = 1; if(stats->bits < 8) stats->bits = 8; /*PNG has no colored modes with less than 8-bit per channel*/ } if(!alpha_done) { unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b); if(a != 255 && (a != 0 || (stats->key && !matchkey))) { stats->alpha = 1; stats->key = 0; alpha_done = 1; if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ } else if(a == 0 && !stats->alpha && !stats->key) { stats->key = 1; stats->key_r = r; stats->key_g = g; stats->key_b = b; } else if(a == 255 && stats->key && matchkey) { /* Color key cannot be used if an opaque pixel also has that RGB color. */ stats->alpha = 1; stats->key = 0; alpha_done = 1; if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ } } if(!numcolors_done) { if(!color_tree_has(&tree, r, g, b, a)) { error = color_tree_add(&tree, r, g, b, a, stats->numcolors); if(error) goto cleanup; if(stats->numcolors < 256) { unsigned char* p = stats->palette; unsigned n = stats->numcolors; p[n * 4 + 0] = r; p[n * 4 + 1] = g; p[n * 4 + 2] = b; p[n * 4 + 3] = a; } ++stats->numcolors; numcolors_done = stats->numcolors >= maxnumcolors; } } if(alpha_done && numcolors_done && colored_done && bits_done) break; } if(stats->key && !stats->alpha) { for(i = 0; i != numpixels; ++i) { getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) { /* Color key cannot be used if an opaque pixel also has that RGB color. */ stats->alpha = 1; stats->key = 0; alpha_done = 1; if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ } } } /*make the stats's key always 16-bit for consistency - repeat each byte twice*/ stats->key_r += (stats->key_r << 8); stats->key_g += (stats->key_g << 8); stats->key_b += (stats->key_b << 8); } cleanup: color_tree_cleanup(&tree); return error; } #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*Adds a single color to the color stats. The stats must already have been inited. The color must be given as 16-bit (with 2 bytes repeating for 8-bit and 65535 for opaque alpha channel). This function is expensive, do not call it for all pixels of an image but only for a few additional values. */ static unsigned lodepng_color_stats_add(LodePNGColorStats* stats, unsigned r, unsigned g, unsigned b, unsigned a) { unsigned error = 0; unsigned char image[8]; LodePNGColorMode mode; lodepng_color_mode_init(&mode); image[0] = r >> 8; image[1] = r; image[2] = g >> 8; image[3] = g; image[4] = b >> 8; image[5] = b; image[6] = a >> 8; image[7] = a; mode.bitdepth = 16; mode.colortype = LCT_RGBA; error = lodepng_compute_color_stats(stats, image, 1, 1, &mode); lodepng_color_mode_cleanup(&mode); return error; } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /*Computes a minimal PNG color model that can contain all colors as indicated by the stats. The stats should be computed with lodepng_compute_color_stats. mode_in is raw color profile of the image the stats were computed on, to copy palette order from when relevant. Minimal PNG color model means the color type and bit depth that gives smallest amount of bits in the output image, e.g. gray if only grayscale pixels, palette if less than 256 colors, color key if only single transparent color, ... This is used if auto_convert is enabled (it is by default). */ static unsigned auto_choose_color(LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, const LodePNGColorStats* stats) { unsigned error = 0; unsigned palettebits; size_t i, n; size_t numpixels = stats->numpixels; unsigned palette_ok, gray_ok; unsigned alpha = stats->alpha; unsigned key = stats->key; unsigned bits = stats->bits; mode_out->key_defined = 0; if(key && numpixels <= 16) { alpha = 1; /*too few pixels to justify tRNS chunk overhead*/ key = 0; if(bits < 8) bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ } gray_ok = !stats->colored; if(!stats->allow_greyscale) gray_ok = 0; if(!gray_ok && bits < 8) bits = 8; n = stats->numcolors; palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8)); palette_ok = n <= 256 && bits <= 8 && n != 0; /*n==0 means likely numcolors wasn't computed*/ if(numpixels < n * 2) palette_ok = 0; /*don't add palette overhead if image has only a few pixels*/ if(gray_ok && !alpha && bits <= palettebits) palette_ok = 0; /*gray is less overhead*/ if(!stats->allow_palette) palette_ok = 0; if(palette_ok) { const unsigned char* p = stats->palette; lodepng_palette_clear(mode_out); /*remove potential earlier palette*/ for(i = 0; i != stats->numcolors; ++i) { error = lodepng_palette_add(mode_out, p[i * 4 + 0], p[i * 4 + 1], p[i * 4 + 2], p[i * 4 + 3]); if(error) break; } mode_out->colortype = LCT_PALETTE; mode_out->bitdepth = palettebits; if(mode_in->colortype == LCT_PALETTE && mode_in->palettesize >= mode_out->palettesize && mode_in->bitdepth == mode_out->bitdepth) { /*If input should have same palette colors, keep original to preserve its order and prevent conversion*/ lodepng_color_mode_cleanup(mode_out); /*clears palette, keeps the above set colortype and bitdepth fields as-is*/ lodepng_color_mode_copy(mode_out, mode_in); } } else /*8-bit or 16-bit per channel*/ { mode_out->bitdepth = bits; mode_out->colortype = alpha ? (gray_ok ? LCT_GREY_ALPHA : LCT_RGBA) : (gray_ok ? LCT_GREY : LCT_RGB); if(key) { unsigned mask = (1u << mode_out->bitdepth) - 1u; /*stats always uses 16-bit, mask converts it*/ mode_out->key_r = stats->key_r & mask; mode_out->key_g = stats->key_g & mask; mode_out->key_b = stats->key_b & mask; mode_out->key_defined = 1; } } return error; } #endif /* #ifdef LODEPNG_COMPILE_ENCODER */ /*Paeth predictor, used by PNG filter type 4*/ static unsigned char paethPredictor(unsigned char a, unsigned char b, unsigned char c) { /* the subtractions of unsigned char cast it to a signed type. With gcc, short is faster than int, with clang int is as fast (as of april 2023)*/ short pa = (b - c) < 0 ? -(b - c) : (b - c); short pb = (a - c) < 0 ? -(a - c) : (a - c); /* writing it out like this compiles to something faster than introducing a temp variable*/ short pc = (a + b - c - c) < 0 ? -(a + b - c - c) : (a + b - c - c); /* return input value associated with smallest of pa, pb, pc (with certain priority if equal) */ if(pb < pa) { a = b; pa = pb; } return (pc < pa) ? c : a; } /*shared values used by multiple Adam7 related functions*/ static const unsigned ADAM7_IX[7] = { 0, 4, 0, 2, 0, 1, 0 }; /*x start values*/ static const unsigned ADAM7_IY[7] = { 0, 0, 4, 0, 2, 0, 1 }; /*y start values*/ static const unsigned ADAM7_DX[7] = { 8, 8, 4, 4, 2, 2, 1 }; /*x delta values*/ static const unsigned ADAM7_DY[7] = { 8, 8, 8, 4, 4, 2, 2 }; /*y delta values*/ /* Outputs various dimensions and positions in the image related to the Adam7 reduced images. passw: output containing the width of the 7 passes passh: output containing the height of the 7 passes filter_passstart: output containing the index of the start and end of each reduced image with filter bytes padded_passstart output containing the index of the start and end of each reduced image when without filter bytes but with padded scanlines passstart: output containing the index of the start and end of each reduced image without padding between scanlines, but still padding between the images w, h: width and height of non-interlaced image bpp: bits per pixel "padded" is only relevant if bpp is less than 8 and a scanline or image does not end at a full byte */ static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8], size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp) { /*the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass*/ unsigned i; /*calculate width and height in pixels of each pass*/ for(i = 0; i != 7; ++i) { passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i]; passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i]; if(passw[i] == 0) passh[i] = 0; if(passh[i] == 0) passw[i] = 0; } filter_passstart[0] = padded_passstart[0] = passstart[0] = 0; for(i = 0; i != 7; ++i) { /*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/ filter_passstart[i + 1] = filter_passstart[i] + ((passw[i] && passh[i]) ? passh[i] * (1u + (passw[i] * bpp + 7u) / 8u) : 0); /*bits padded if needed to fill full byte at end of each scanline*/ padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7u) / 8u); /*only padded at end of reduced image*/ passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7u) / 8u; } } #ifdef LODEPNG_COMPILE_DECODER /* ////////////////////////////////////////////////////////////////////////// */ /* / PNG Decoder / */ /* ////////////////////////////////////////////////////////////////////////// */ /*read the information from the header and store it in the LodePNGInfo. return value is error*/ unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize) { unsigned width, height; LodePNGInfo* info = &state->info_png; if(insize == 0 || in == 0) { CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/ } if(insize < 33) { CERROR_RETURN_ERROR(state->error, 27); /*error: the data length is smaller than the length of a PNG header*/ } /*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/ /* TODO: remove this. One should use a new LodePNGState for new sessions */ lodepng_info_cleanup(info); lodepng_info_init(info); if(in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71 || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) { CERROR_RETURN_ERROR(state->error, 28); /*error: the first 8 bytes are not the correct PNG signature*/ } if(lodepng_chunk_length(in + 8) != 13) { CERROR_RETURN_ERROR(state->error, 94); /*error: header size must be 13 bytes*/ } if(!lodepng_chunk_type_equals(in + 8, "IHDR")) { CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/ } /*read the values given in the header*/ width = lodepng_read32bitInt(&in[16]); height = lodepng_read32bitInt(&in[20]); /*TODO: remove the undocumented feature that allows to give null pointers to width or height*/ if(w) *w = width; if(h) *h = height; info->color.bitdepth = in[24]; info->color.colortype = (LodePNGColorType)in[25]; info->compression_method = in[26]; info->filter_method = in[27]; info->interlace_method = in[28]; /*errors returned only after the parsing so other values are still output*/ /*error: invalid image size*/ if(width == 0 || height == 0) CERROR_RETURN_ERROR(state->error, 93); /*error: invalid colortype or bitdepth combination*/ state->error = checkColorValidity(info->color.colortype, info->color.bitdepth); if(state->error) return state->error; /*error: only compression method 0 is allowed in the specification*/ if(info->compression_method != 0) CERROR_RETURN_ERROR(state->error, 32); /*error: only filter method 0 is allowed in the specification*/ if(info->filter_method != 0) CERROR_RETURN_ERROR(state->error, 33); /*error: only interlace methods 0 and 1 exist in the specification*/ if(info->interlace_method > 1) CERROR_RETURN_ERROR(state->error, 34); if(!state->decoder.ignore_crc) { unsigned crc = lodepng_read32bitInt(&in[29]); unsigned checksum = lodepng_crc32(&in[12], 17); if(crc != checksum) { CERROR_RETURN_ERROR(state->error, 57); /*invalid CRC*/ } } return state->error; } static unsigned unfilterScanline(unsigned char* recon, const unsigned char* scanline, const unsigned char* precon, size_t bytewidth, unsigned char filterType, size_t length) { /* For PNG filter method 0 unfilter a PNG image scanline by scanline. when the pixels are smaller than 1 byte, the filter works byte per byte (bytewidth = 1) precon is the previous unfiltered scanline, recon the result, scanline the current one the incoming scanlines do NOT include the filtertype byte, that one is given in the parameter filterType instead recon and scanline MAY be the same memory address! precon must be disjoint. */ size_t i; switch(filterType) { case 0: for(i = 0; i != length; ++i) recon[i] = scanline[i]; break; case 1: { size_t j = 0; for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i]; for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + recon[j]; break; } case 2: if(precon) { for(i = 0; i != length; ++i) recon[i] = scanline[i] + precon[i]; } else { for(i = 0; i != length; ++i) recon[i] = scanline[i]; } break; case 3: if(precon) { size_t j = 0; for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i] + (precon[i] >> 1u); /* Unroll independent paths of this predictor. A 6x and 8x version is also possible but that adds too much code. Whether this speeds up anything depends on compiler and settings. */ if(bytewidth >= 4) { for(; i + 3 < length; i += 4, j += 4) { unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2], s3 = scanline[i + 3]; unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2], r3 = recon[j + 3]; unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2], p3 = precon[i + 3]; recon[i + 0] = s0 + ((r0 + p0) >> 1u); recon[i + 1] = s1 + ((r1 + p1) >> 1u); recon[i + 2] = s2 + ((r2 + p2) >> 1u); recon[i + 3] = s3 + ((r3 + p3) >> 1u); } } else if(bytewidth >= 3) { for(; i + 2 < length; i += 3, j += 3) { unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2]; unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2]; unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2]; recon[i + 0] = s0 + ((r0 + p0) >> 1u); recon[i + 1] = s1 + ((r1 + p1) >> 1u); recon[i + 2] = s2 + ((r2 + p2) >> 1u); } } else if(bytewidth >= 2) { for(; i + 1 < length; i += 2, j += 2) { unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1]; unsigned char r0 = recon[j + 0], r1 = recon[j + 1]; unsigned char p0 = precon[i + 0], p1 = precon[i + 1]; recon[i + 0] = s0 + ((r0 + p0) >> 1u); recon[i + 1] = s1 + ((r1 + p1) >> 1u); } } for(; i != length; ++i, ++j) recon[i] = scanline[i] + ((recon[j] + precon[i]) >> 1u); } else { size_t j = 0; for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i]; for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + (recon[j] >> 1u); } break; case 4: if(precon) { /* Unroll independent paths of this predictor. Whether this speeds up anything depends on compiler and settings. */ if(bytewidth == 8) { unsigned char a0, b0 = 0, c0, d0 = 0, a1, b1 = 0, c1, d1 = 0; unsigned char a2, b2 = 0, c2, d2 = 0, a3, b3 = 0, c3, d3 = 0; unsigned char a4, b4 = 0, c4, d4 = 0, a5, b5 = 0, c5, d5 = 0; unsigned char a6, b6 = 0, c6, d6 = 0, a7, b7 = 0, c7, d7 = 0; for(i = 0; i + 7 < length; i += 8) { c0 = b0; c1 = b1; c2 = b2; c3 = b3; c4 = b4; c5 = b5; c6 = b6; c7 = b7; b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2]; b3 = precon[i + 3]; b4 = precon[i + 4]; b5 = precon[i + 5]; b6 = precon[i + 6]; b7 = precon[i + 7]; a0 = d0; a1 = d1; a2 = d2; a3 = d3; a4 = d4; a5 = d5; a6 = d6; a7 = d7; d0 = scanline[i + 0] + paethPredictor(a0, b0, c0); d1 = scanline[i + 1] + paethPredictor(a1, b1, c1); d2 = scanline[i + 2] + paethPredictor(a2, b2, c2); d3 = scanline[i + 3] + paethPredictor(a3, b3, c3); d4 = scanline[i + 4] + paethPredictor(a4, b4, c4); d5 = scanline[i + 5] + paethPredictor(a5, b5, c5); d6 = scanline[i + 6] + paethPredictor(a6, b6, c6); d7 = scanline[i + 7] + paethPredictor(a7, b7, c7); recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2; recon[i + 3] = d3; recon[i + 4] = d4; recon[i + 5] = d5; recon[i + 6] = d6; recon[i + 7] = d7; } } else if(bytewidth == 6) { unsigned char a0, b0 = 0, c0, d0 = 0, a1, b1 = 0, c1, d1 = 0; unsigned char a2, b2 = 0, c2, d2 = 0, a3, b3 = 0, c3, d3 = 0; unsigned char a4, b4 = 0, c4, d4 = 0, a5, b5 = 0, c5, d5 = 0; for(i = 0; i + 5 < length; i += 6) { c0 = b0; c1 = b1; c2 = b2; c3 = b3; c4 = b4; c5 = b5; b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2]; b3 = precon[i + 3]; b4 = precon[i + 4]; b5 = precon[i + 5]; a0 = d0; a1 = d1; a2 = d2; a3 = d3; a4 = d4; a5 = d5; d0 = scanline[i + 0] + paethPredictor(a0, b0, c0); d1 = scanline[i + 1] + paethPredictor(a1, b1, c1); d2 = scanline[i + 2] + paethPredictor(a2, b2, c2); d3 = scanline[i + 3] + paethPredictor(a3, b3, c3); d4 = scanline[i + 4] + paethPredictor(a4, b4, c4); d5 = scanline[i + 5] + paethPredictor(a5, b5, c5); recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2; recon[i + 3] = d3; recon[i + 4] = d4; recon[i + 5] = d5; } } else if(bytewidth == 4) { unsigned char a0, b0 = 0, c0, d0 = 0, a1, b1 = 0, c1, d1 = 0; unsigned char a2, b2 = 0, c2, d2 = 0, a3, b3 = 0, c3, d3 = 0; for(i = 0; i + 3 < length; i += 4) { c0 = b0; c1 = b1; c2 = b2; c3 = b3; b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2]; b3 = precon[i + 3]; a0 = d0; a1 = d1; a2 = d2; a3 = d3; d0 = scanline[i + 0] + paethPredictor(a0, b0, c0); d1 = scanline[i + 1] + paethPredictor(a1, b1, c1); d2 = scanline[i + 2] + paethPredictor(a2, b2, c2); d3 = scanline[i + 3] + paethPredictor(a3, b3, c3); recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2; recon[i + 3] = d3; } } else if(bytewidth == 3) { unsigned char a0, b0 = 0, c0, d0 = 0; unsigned char a1, b1 = 0, c1, d1 = 0; unsigned char a2, b2 = 0, c2, d2 = 0; for(i = 0; i + 2 < length; i += 3) { c0 = b0; c1 = b1; c2 = b2; b0 = precon[i + 0]; b1 = precon[i + 1]; b2 = precon[i + 2]; a0 = d0; a1 = d1; a2 = d2; d0 = scanline[i + 0] + paethPredictor(a0, b0, c0); d1 = scanline[i + 1] + paethPredictor(a1, b1, c1); d2 = scanline[i + 2] + paethPredictor(a2, b2, c2); recon[i + 0] = d0; recon[i + 1] = d1; recon[i + 2] = d2; } } else if(bytewidth == 2) { unsigned char a0, b0 = 0, c0, d0 = 0; unsigned char a1, b1 = 0, c1, d1 = 0; for(i = 0; i + 1 < length; i += 2) { c0 = b0; c1 = b1; b0 = precon[i + 0]; b1 = precon[i + 1]; a0 = d0; a1 = d1; d0 = scanline[i + 0] + paethPredictor(a0, b0, c0); d1 = scanline[i + 1] + paethPredictor(a1, b1, c1); recon[i + 0] = d0; recon[i + 1] = d1; } } else if(bytewidth == 1) { unsigned char a, b = 0, c, d = 0; for(i = 0; i != length; ++i) { c = b; b = precon[i]; a = d; d = scanline[i] + paethPredictor(a, b, c); recon[i] = d; } } else { /* Normally not a possible case, but this would handle it correctly */ for(i = 0; i != bytewidth; ++i) { recon[i] = (scanline[i] + precon[i]); /*paethPredictor(0, precon[i], 0) is always precon[i]*/ } } /* finish any remaining bytes */ for(; i != length; ++i) { recon[i] = (scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[i - bytewidth])); } } else { size_t j = 0; for(i = 0; i != bytewidth; ++i) { recon[i] = scanline[i]; } for(i = bytewidth; i != length; ++i, ++j) { /*paethPredictor(recon[i - bytewidth], 0, 0) is always recon[i - bytewidth]*/ recon[i] = (scanline[i] + recon[j]); } } break; default: return 36; /*error: invalid filter type given*/ } return 0; } static unsigned unfilter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { /* For PNG filter method 0 this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times) out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes) */ unsigned y; unsigned char* prevline = 0; /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/ size_t bytewidth = (bpp + 7u) / 8u; /*the width of a scanline in bytes, not including the filter type*/ size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u; for(y = 0; y < h; ++y) { size_t outindex = linebytes * y; size_t inindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ unsigned char filterType = in[inindex]; CERROR_TRY_RETURN(unfilterScanline(&out[outindex], &in[inindex + 1], prevline, bytewidth, filterType, linebytes)); prevline = &out[outindex]; } return 0; } /* in: Adam7 interlaced image, with no padding bits between scanlines, but between reduced images so that each reduced image starts at a byte. out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h bpp: bits per pixel out has the following size in bits: w * h * bpp. in is possibly bigger due to padding bits between reduced images. out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation (because that's likely a little bit faster) NOTE: comments about padding bits are only relevant if bpp < 8 */ static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8]; unsigned i; Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); if(bpp >= 8) { for(i = 0; i != 7; ++i) { unsigned x, y, b; size_t bytewidth = bpp / 8u; for(y = 0; y < passh[i]; ++y) for(x = 0; x < passw[i]; ++x) { size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth; size_t pixeloutstart = ((ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * (size_t)w + ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bytewidth; for(b = 0; b < bytewidth; ++b) { out[pixeloutstart + b] = in[pixelinstart + b]; } } } } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ { for(i = 0; i != 7; ++i) { unsigned x, y, b; unsigned ilinebits = bpp * passw[i]; unsigned olinebits = bpp * w; size_t obp, ibp; /*bit pointers (for out and in buffer)*/ for(y = 0; y < passh[i]; ++y) for(x = 0; x < passw[i]; ++x) { ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp); obp = (ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bpp; for(b = 0; b < bpp; ++b) { unsigned char bit = readBitFromReversedStream(&ibp, in); setBitOfReversedStream(&obp, out, bit); } } } } } static void removePaddingBits(unsigned char* out, const unsigned char* in, size_t olinebits, size_t ilinebits, unsigned h) { /* After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers for the Adam7 code, the color convert code and the output to the user. in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7 only useful if (ilinebits - olinebits) is a value in the range 1..7 */ unsigned y; size_t diff = ilinebits - olinebits; size_t ibp = 0, obp = 0; /*input and output bit pointers*/ for(y = 0; y < h; ++y) { size_t x; for(x = 0; x < olinebits; ++x) { unsigned char bit = readBitFromReversedStream(&ibp, in); setBitOfReversedStream(&obp, out, bit); } ibp += diff; } } /*out must be buffer big enough to contain full image, and in must contain the full decompressed data from the IDAT chunks (with filter index bytes and possible padding bits) return value is error*/ static unsigned postProcessScanlines(unsigned char* out, unsigned char* in, unsigned w, unsigned h, const LodePNGInfo* info_png) { /* This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype. Steps: *) if no Adam7: 1) unfilter 2) remove padding bits (= possible extra bits per scanline if bpp < 8) *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace NOTE: the in buffer will be overwritten with intermediate data! */ unsigned bpp = lodepng_get_bpp(&info_png->color); if(bpp == 0) return 31; /*error: invalid colortype*/ if(info_png->interlace_method == 0) { if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) { CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp)); removePaddingBits(out, in, w * bpp, ((w * bpp + 7u) / 8u) * 8u, h); } /*we can immediately filter into the out buffer, no other steps needed*/ else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp)); } else /*interlace_method is 1 (Adam7)*/ { unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8]; unsigned i; Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); for(i = 0; i != 7; ++i) { CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp)); /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline, move bytes instead of bits or move not at all*/ if(bpp < 8) { /*remove padding bits in scanlines; after this there still may be padding bits between the different reduced images: each reduced image still starts nicely at a byte*/ removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp, ((passw[i] * bpp + 7u) / 8u) * 8u, passh[i]); } } Adam7_deinterlace(out, in, w, h, bpp); } return 0; } static unsigned readChunk_PLTE(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) { unsigned pos = 0, i; color->palettesize = chunkLength / 3u; if(color->palettesize == 0 || color->palettesize > 256) return 38; /*error: palette too small or big*/ lodepng_color_mode_alloc_palette(color); if(!color->palette && color->palettesize) { color->palettesize = 0; return 83; /*alloc fail*/ } for(i = 0; i != color->palettesize; ++i) { color->palette[4 * i + 0] = data[pos++]; /*R*/ color->palette[4 * i + 1] = data[pos++]; /*G*/ color->palette[4 * i + 2] = data[pos++]; /*B*/ color->palette[4 * i + 3] = 255; /*alpha*/ } return 0; /* OK */ } static unsigned readChunk_tRNS(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) { unsigned i; if(color->colortype == LCT_PALETTE) { /*error: more alpha values given than there are palette entries*/ if(chunkLength > color->palettesize) return 39; for(i = 0; i != chunkLength; ++i) color->palette[4 * i + 3] = data[i]; } else if(color->colortype == LCT_GREY) { /*error: this chunk must be 2 bytes for grayscale image*/ if(chunkLength != 2) return 30; color->key_defined = 1; color->key_r = color->key_g = color->key_b = 256u * data[0] + data[1]; } else if(color->colortype == LCT_RGB) { /*error: this chunk must be 6 bytes for RGB image*/ if(chunkLength != 6) return 41; color->key_defined = 1; color->key_r = 256u * data[0] + data[1]; color->key_g = 256u * data[2] + data[3]; color->key_b = 256u * data[4] + data[5]; } else return 42; /*error: tRNS chunk not allowed for other color models*/ return 0; /* OK */ } #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*background color chunk (bKGD)*/ static unsigned readChunk_bKGD(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(info->color.colortype == LCT_PALETTE) { /*error: this chunk must be 1 byte for indexed color image*/ if(chunkLength != 1) return 43; /*error: invalid palette index, or maybe this chunk appeared before PLTE*/ if(data[0] >= info->color.palettesize) return 103; info->background_defined = 1; info->background_r = info->background_g = info->background_b = data[0]; } else if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) { /*error: this chunk must be 2 bytes for grayscale image*/ if(chunkLength != 2) return 44; /*the values are truncated to bitdepth in the PNG file*/ info->background_defined = 1; info->background_r = info->background_g = info->background_b = 256u * data[0] + data[1]; } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) { /*error: this chunk must be 6 bytes for grayscale image*/ if(chunkLength != 6) return 45; /*the values are truncated to bitdepth in the PNG file*/ info->background_defined = 1; info->background_r = 256u * data[0] + data[1]; info->background_g = 256u * data[2] + data[3]; info->background_b = 256u * data[4] + data[5]; } return 0; /* OK */ } /*text chunk (tEXt)*/ static unsigned readChunk_tEXt(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { unsigned error = 0; char *key = 0, *str = 0; while(!error) /*not really a while loop, only used to break on error*/ { unsigned length, string2_begin; length = 0; while(length < chunkLength && data[length] != 0) ++length; /*even though it's not allowed by the standard, no error is thrown if there's no null termination char, if the text is empty*/ if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ key = (char*)lodepng_malloc(length + 1); if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ lodepng_memcpy(key, data, length); key[length] = 0; string2_begin = length + 1; /*skip keyword null terminator*/ length = (unsigned)(chunkLength < string2_begin ? 0 : chunkLength - string2_begin); str = (char*)lodepng_malloc(length + 1); if(!str) CERROR_BREAK(error, 83); /*alloc fail*/ lodepng_memcpy(str, data + string2_begin, length); str[length] = 0; error = lodepng_add_text(info, key, str); break; } lodepng_free(key); lodepng_free(str); return error; } /*compressed text chunk (zTXt)*/ static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder, const unsigned char* data, size_t chunkLength) { unsigned error = 0; /*copy the object to change parameters in it*/ LodePNGDecompressSettings zlibsettings = decoder->zlibsettings; unsigned length, string2_begin; char *key = 0; unsigned char* str = 0; size_t size = 0; while(!error) /*not really a while loop, only used to break on error*/ { for(length = 0; length < chunkLength && data[length] != 0; ++length) ; if(length + 2 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/ if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ key = (char*)lodepng_malloc(length + 1); if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ lodepng_memcpy(key, data, length); key[length] = 0; if(data[length + 1] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/ string2_begin = length + 2; if(string2_begin > chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/ length = (unsigned)chunkLength - string2_begin; zlibsettings.max_output_size = decoder->max_text_size; /*will fail if zlib error, e.g. if length is too small*/ error = zlib_decompress(&str, &size, 0, &data[string2_begin], length, &zlibsettings); /*error: compressed text larger than decoder->max_text_size*/ if(error && size > zlibsettings.max_output_size) error = 112; if(error) break; error = lodepng_add_text_sized(info, key, (char*)str, size); break; } lodepng_free(key); lodepng_free(str); return error; } /*international text chunk (iTXt)*/ static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder, const unsigned char* data, size_t chunkLength) { unsigned error = 0; unsigned i; /*copy the object to change parameters in it*/ LodePNGDecompressSettings zlibsettings = decoder->zlibsettings; unsigned length, begin, compressed; char *key = 0, *langtag = 0, *transkey = 0; while(!error) /*not really a while loop, only used to break on error*/ { /*Quick check if the chunk length isn't too small. Even without check it'd still fail with other error checks below if it's too short. This just gives a different error code.*/ if(chunkLength < 5) CERROR_BREAK(error, 30); /*iTXt chunk too short*/ /*read the key*/ for(length = 0; length < chunkLength && data[length] != 0; ++length) ; if(length + 3 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination char, corrupt?*/ if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ key = (char*)lodepng_malloc(length + 1); if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ lodepng_memcpy(key, data, length); key[length] = 0; /*read the compression method*/ compressed = data[length + 1]; if(data[length + 2] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/ /*even though it's not allowed by the standard, no error is thrown if there's no null termination char, if the text is empty for the next 3 texts*/ /*read the langtag*/ begin = length + 3; length = 0; for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length; langtag = (char*)lodepng_malloc(length + 1); if(!langtag) CERROR_BREAK(error, 83); /*alloc fail*/ lodepng_memcpy(langtag, data + begin, length); langtag[length] = 0; /*read the transkey*/ begin += length + 1; length = 0; for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length; transkey = (char*)lodepng_malloc(length + 1); if(!transkey) CERROR_BREAK(error, 83); /*alloc fail*/ lodepng_memcpy(transkey, data + begin, length); transkey[length] = 0; /*read the actual text*/ begin += length + 1; length = (unsigned)chunkLength < begin ? 0 : (unsigned)chunkLength - begin; if(compressed) { unsigned char* str = 0; size_t size = 0; zlibsettings.max_output_size = decoder->max_text_size; /*will fail if zlib error, e.g. if length is too small*/ error = zlib_decompress(&str, &size, 0, &data[begin], length, &zlibsettings); /*error: compressed text larger than decoder->max_text_size*/ if(error && size > zlibsettings.max_output_size) error = 112; if(!error) error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)str, size); lodepng_free(str); } else { error = lodepng_add_itext_sized(info, key, langtag, transkey, (const char*)(data + begin), length); } break; } lodepng_free(key); lodepng_free(langtag); lodepng_free(transkey); return error; } static unsigned readChunk_tIME(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 7) return 73; /*invalid tIME chunk size*/ info->time_defined = 1; info->time.year = 256u * data[0] + data[1]; info->time.month = data[2]; info->time.day = data[3]; info->time.hour = data[4]; info->time.minute = data[5]; info->time.second = data[6]; return 0; /* OK */ } static unsigned readChunk_pHYs(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 9) return 74; /*invalid pHYs chunk size*/ info->phys_defined = 1; info->phys_x = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3]; info->phys_y = 16777216u * data[4] + 65536u * data[5] + 256u * data[6] + data[7]; info->phys_unit = data[8]; return 0; /* OK */ } static unsigned readChunk_gAMA(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 4) return 96; /*invalid gAMA chunk size*/ info->gama_defined = 1; info->gama_gamma = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3]; return 0; /* OK */ } static unsigned readChunk_cHRM(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 32) return 97; /*invalid cHRM chunk size*/ info->chrm_defined = 1; info->chrm_white_x = 16777216u * data[ 0] + 65536u * data[ 1] + 256u * data[ 2] + data[ 3]; info->chrm_white_y = 16777216u * data[ 4] + 65536u * data[ 5] + 256u * data[ 6] + data[ 7]; info->chrm_red_x = 16777216u * data[ 8] + 65536u * data[ 9] + 256u * data[10] + data[11]; info->chrm_red_y = 16777216u * data[12] + 65536u * data[13] + 256u * data[14] + data[15]; info->chrm_green_x = 16777216u * data[16] + 65536u * data[17] + 256u * data[18] + data[19]; info->chrm_green_y = 16777216u * data[20] + 65536u * data[21] + 256u * data[22] + data[23]; info->chrm_blue_x = 16777216u * data[24] + 65536u * data[25] + 256u * data[26] + data[27]; info->chrm_blue_y = 16777216u * data[28] + 65536u * data[29] + 256u * data[30] + data[31]; return 0; /* OK */ } static unsigned readChunk_sRGB(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 1) return 98; /*invalid sRGB chunk size (this one is never ignored)*/ info->srgb_defined = 1; info->srgb_intent = data[0]; return 0; /* OK */ } static unsigned readChunk_iCCP(LodePNGInfo* info, const LodePNGDecoderSettings* decoder, const unsigned char* data, size_t chunkLength) { unsigned error = 0; unsigned i; size_t size = 0; /*copy the object to change parameters in it*/ LodePNGDecompressSettings zlibsettings = decoder->zlibsettings; unsigned length, string2_begin; if(info->iccp_defined) lodepng_clear_icc(info); for(length = 0; length < chunkLength && data[length] != 0; ++length) ; if(length + 2 >= chunkLength) return 75; /*no null termination, corrupt?*/ if(length < 1 || length > 79) return 89; /*keyword too short or long*/ info->iccp_name = (char*)lodepng_malloc(length + 1); if(!info->iccp_name) return 83; /*alloc fail*/ info->iccp_name[length] = 0; for(i = 0; i != length; ++i) info->iccp_name[i] = (char)data[i]; if(data[length + 1] != 0) return 72; /*the 0 byte indicating compression must be 0*/ string2_begin = length + 2; if(string2_begin > chunkLength) return 75; /*no null termination, corrupt?*/ length = (unsigned)chunkLength - string2_begin; zlibsettings.max_output_size = decoder->max_icc_size; error = zlib_decompress(&info->iccp_profile, &size, 0, &data[string2_begin], length, &zlibsettings); /*error: ICC profile larger than decoder->max_icc_size*/ if(error && size > zlibsettings.max_output_size) error = 113; info->iccp_profile_size = (unsigned)size; if(!error && !info->iccp_profile_size) error = 123; /*invalid ICC profile size*/ if(!error) info->iccp_defined = 1; return error; } static unsigned readChunk_cICP(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 4) return 117; /*invalid cICP chunk size*/ info->cicp_defined = 1; /* No error checking for value ranges is done here, that is up to a CICP handling library, not the PNG decoding. Just pass on the metadata. */ info->cicp_color_primaries = data[0]; info->cicp_transfer_function = data[1]; info->cicp_matrix_coefficients = data[2]; info->cicp_video_full_range_flag = data[3]; return 0; /* OK */ } static unsigned readChunk_mDCV(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 24) return 119; /*invalid mDCV chunk size*/ info->mdcv_defined = 1; info->mdcv_red_x = 256u * data[0] + data[1]; info->mdcv_red_y = 256u * data[2] + data[3]; info->mdcv_green_x = 256u * data[4] + data[5]; info->mdcv_green_y = 256u * data[6] + data[7]; info->mdcv_blue_x = 256u * data[8] + data[9]; info->mdcv_blue_y = 256u * data[10] + data[11]; info->mdcv_white_x = 256u * data[12] + data[13]; info->mdcv_white_y = 256u * data[14] + data[15]; info->mdcv_max_luminance = 16777216u * data[16] + 65536u * data[17] + 256u * data[18] + data[19]; info->mdcv_min_luminance = 16777216u * data[20] + 65536u * data[21] + 256u * data[22] + data[23]; return 0; /* OK */ } static unsigned readChunk_cLLI(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { if(chunkLength != 8) return 120; /*invalid cLLI chunk size*/ info->clli_defined = 1; info->clli_max_cll = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3]; info->clli_max_fall = 16777216u * data[4] + 65536u * data[5] + 256u * data[6] + data[7]; return 0; /* OK */ } static unsigned readChunk_eXIf(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { return lodepng_set_exif(info, data, (unsigned)chunkLength); } /*significant bits chunk (sBIT)*/ static unsigned readChunk_sBIT(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { unsigned bitdepth = (info->color.colortype == LCT_PALETTE) ? 8 : info->color.bitdepth; if(info->color.colortype == LCT_GREY) { /*error: this chunk must be 1 bytes for grayscale image*/ if(chunkLength != 1) return 114; if(data[0] == 0 || data[0] > bitdepth) return 115; info->sbit_defined = 1; info->sbit_r = info->sbit_g = info->sbit_b = data[0]; /*setting g and b is not required, but sensible*/ } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_PALETTE) { /*error: this chunk must be 3 bytes for RGB and palette image*/ if(chunkLength != 3) return 114; if(data[0] == 0 || data[1] == 0 || data[2] == 0) return 115; if(data[0] > bitdepth || data[1] > bitdepth || data[2] > bitdepth) return 115; info->sbit_defined = 1; info->sbit_r = data[0]; info->sbit_g = data[1]; info->sbit_b = data[2]; } else if(info->color.colortype == LCT_GREY_ALPHA) { /*error: this chunk must be 2 byte for grayscale with alpha image*/ if(chunkLength != 2) return 114; if(data[0] == 0 || data[1] == 0) return 115; if(data[0] > bitdepth || data[1] > bitdepth) return 115; info->sbit_defined = 1; info->sbit_r = info->sbit_g = info->sbit_b = data[0]; /*setting g and b is not required, but sensible*/ info->sbit_a = data[1]; } else if(info->color.colortype == LCT_RGBA) { /*error: this chunk must be 4 bytes for grayscale image*/ if(chunkLength != 4) return 114; if(data[0] == 0 || data[1] == 0 || data[2] == 0 || data[3] == 0) return 115; if(data[0] > bitdepth || data[1] > bitdepth || data[2] > bitdepth || data[3] > bitdepth) return 115; info->sbit_defined = 1; info->sbit_r = data[0]; info->sbit_g = data[1]; info->sbit_b = data[2]; info->sbit_a = data[3]; } return 0; /* OK */ } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos, const unsigned char* in, size_t insize) { const unsigned char* chunk = in + pos; unsigned chunkLength; const unsigned char* data; unsigned unhandled = 0; unsigned error = 0; if(pos + 4 > insize) return 30; chunkLength = lodepng_chunk_length(chunk); if(chunkLength > 2147483647) return 63; data = lodepng_chunk_data_const(chunk); if(chunkLength + 12 > insize - pos) return 30; if(lodepng_chunk_type_equals(chunk, "PLTE")) { error = readChunk_PLTE(&state->info_png.color, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "tRNS")) { error = readChunk_tRNS(&state->info_png.color, data, chunkLength); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS } else if(lodepng_chunk_type_equals(chunk, "bKGD")) { error = readChunk_bKGD(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "tEXt")) { error = readChunk_tEXt(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "zTXt")) { error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "iTXt")) { error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "tIME")) { error = readChunk_tIME(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "pHYs")) { error = readChunk_pHYs(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "gAMA")) { error = readChunk_gAMA(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "cHRM")) { error = readChunk_cHRM(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "sRGB")) { error = readChunk_sRGB(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "iCCP")) { error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "cICP")) { error = readChunk_cICP(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "mDCV")) { error = readChunk_mDCV(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "cLLI")) { error = readChunk_cLLI(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "eXIf")) { error = readChunk_eXIf(&state->info_png, data, chunkLength); } else if(lodepng_chunk_type_equals(chunk, "sBIT")) { error = readChunk_sBIT(&state->info_png, data, chunkLength); #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } else { /* unhandled chunk is ok (is not an error) */ unhandled = 1; } if(!error && !unhandled && !state->decoder.ignore_crc) { if(lodepng_chunk_check_crc(chunk)) return 57; /*invalid CRC*/ } return error; } /*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/ static void decodeGeneric(unsigned char** out, unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize) { unsigned char IEND = 0; const unsigned char* chunk; /*points to beginning of next chunk*/ unsigned char* idat; /*the data from idat chunks, zlib compressed*/ size_t idatsize = 0; unsigned char* scanlines = 0; size_t scanlines_size = 0, expected_size = 0; size_t outsize = 0; /*for unknown chunk order*/ unsigned unknown = 0; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/ #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /* safe output values in case error happens */ *out = 0; *w = *h = 0; state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/ if(state->error) return; if(lodepng_pixel_overflow(*w, *h, &state->info_png.color, &state->info_raw)) { CERROR_RETURN(state->error, 92); /*overflow possible due to amount of pixels*/ } /*the input filesize is a safe upper bound for the sum of idat chunks size*/ idat = (unsigned char*)lodepng_malloc(insize); if(!idat) CERROR_RETURN(state->error, 83); /*alloc fail*/ chunk = &in[33]; /*first byte of the first chunk after the header*/ /*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk. IDAT data is put at the start of the in buffer*/ while(!IEND && !state->error) { unsigned chunkLength; const unsigned char* data; /*the data in the chunk*/ size_t pos = (size_t)(chunk - in); /*error: next chunk out of bounds of the in buffer*/ if(chunk < in || pos + 12 > insize) { if(state->decoder.ignore_end) break; /*other errors may still happen though*/ CERROR_BREAK(state->error, 30); } /*length of the data of the chunk, excluding the 12 bytes for length, chunk type and CRC*/ chunkLength = lodepng_chunk_length(chunk); /*error: chunk length larger than the max PNG chunk size*/ if(chunkLength > 2147483647) { if(state->decoder.ignore_end) break; /*other errors may still happen though*/ CERROR_BREAK(state->error, 63); } if(pos + (size_t)chunkLength + 12 > insize || pos + (size_t)chunkLength + 12 < pos) { CERROR_BREAK(state->error, 64); /*error: size of the in buffer too small to contain next chunk (or int overflow)*/ } data = lodepng_chunk_data_const(chunk); unknown = 0; /*IDAT chunk, containing compressed image data*/ if(lodepng_chunk_type_equals(chunk, "IDAT")) { size_t newsize; if(lodepng_addofl(idatsize, chunkLength, &newsize)) CERROR_BREAK(state->error, 95); if(newsize > insize) CERROR_BREAK(state->error, 95); lodepng_memcpy(idat + idatsize, data, chunkLength); idatsize += chunkLength; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS critical_pos = 3; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } else if(lodepng_chunk_type_equals(chunk, "IEND")) { /*IEND chunk*/ IEND = 1; } else if(lodepng_chunk_type_equals(chunk, "PLTE")) { /*palette chunk (PLTE)*/ state->error = readChunk_PLTE(&state->info_png.color, data, chunkLength); if(state->error) break; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS critical_pos = 2; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } else if(lodepng_chunk_type_equals(chunk, "tRNS")) { /*palette transparency chunk (tRNS). Even though this one is an ancillary chunk , it is still compiled in without 'LODEPNG_COMPILE_ANCILLARY_CHUNKS' because it contains essential color information that affects the alpha channel of pixels. */ state->error = readChunk_tRNS(&state->info_png.color, data, chunkLength); if(state->error) break; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*background color chunk (bKGD)*/ } else if(lodepng_chunk_type_equals(chunk, "bKGD")) { state->error = readChunk_bKGD(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "tEXt")) { /*text chunk (tEXt)*/ if(state->decoder.read_text_chunks) { state->error = readChunk_tEXt(&state->info_png, data, chunkLength); if(state->error) break; } } else if(lodepng_chunk_type_equals(chunk, "zTXt")) { /*compressed text chunk (zTXt)*/ if(state->decoder.read_text_chunks) { state->error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength); if(state->error) break; } } else if(lodepng_chunk_type_equals(chunk, "iTXt")) { /*international text chunk (iTXt)*/ if(state->decoder.read_text_chunks) { state->error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength); if(state->error) break; } } else if(lodepng_chunk_type_equals(chunk, "tIME")) { state->error = readChunk_tIME(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "pHYs")) { state->error = readChunk_pHYs(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "gAMA")) { state->error = readChunk_gAMA(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "cHRM")) { state->error = readChunk_cHRM(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "sRGB")) { state->error = readChunk_sRGB(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "iCCP")) { state->error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "cICP")) { state->error = readChunk_cICP(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "mDCV")) { state->error = readChunk_mDCV(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "cLLI")) { state->error = readChunk_cLLI(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "eXIf")) { state->error = readChunk_eXIf(&state->info_png, data, chunkLength); if(state->error) break; } else if(lodepng_chunk_type_equals(chunk, "sBIT")) { state->error = readChunk_sBIT(&state->info_png, data, chunkLength); if(state->error) break; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } else /*it's not an implemented chunk type, so ignore it: skip over the data*/ { if(!lodepng_chunk_type_name_valid(chunk)) { CERROR_BREAK(state->error, 121); /* invalid chunk type name */ } if(lodepng_chunk_reserved(chunk)) { CERROR_BREAK(state->error, 122); /* invalid third lowercase character */ } /*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/ if(!state->decoder.ignore_critical && !lodepng_chunk_ancillary(chunk)) { CERROR_BREAK(state->error, 69); } unknown = 1; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS if(state->decoder.remember_unknown_chunks) { state->error = lodepng_chunk_append(&state->info_png.unknown_chunks_data[critical_pos - 1], &state->info_png.unknown_chunks_size[critical_pos - 1], chunk); if(state->error) break; } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } if(!state->decoder.ignore_crc && !unknown) /*check CRC if wanted, only on known chunk types*/ { if(lodepng_chunk_check_crc(chunk)) CERROR_BREAK(state->error, 57); /*invalid CRC*/ } if(!IEND) chunk = lodepng_chunk_next_const(chunk, in + insize); } if(!state->error && state->info_png.color.colortype == LCT_PALETTE && !state->info_png.color.palette) { state->error = 106; /* error: PNG file must have PLTE chunk if color type is palette */ } if(!state->error) { /*predict output size, to allocate exact size for output buffer to avoid more dynamic allocation. If the decompressed size does not match the prediction, the image must be corrupt.*/ if(state->info_png.interlace_method == 0) { unsigned bpp = lodepng_get_bpp(&state->info_png.color); expected_size = lodepng_get_raw_size_idat(*w, *h, bpp); } else { unsigned bpp = lodepng_get_bpp(&state->info_png.color); /*Adam-7 interlaced: expected size is the sum of the 7 sub-images sizes*/ expected_size = 0; expected_size += lodepng_get_raw_size_idat((*w + 7) >> 3, (*h + 7) >> 3, bpp); if(*w > 4) expected_size += lodepng_get_raw_size_idat((*w + 3) >> 3, (*h + 7) >> 3, bpp); expected_size += lodepng_get_raw_size_idat((*w + 3) >> 2, (*h + 3) >> 3, bpp); if(*w > 2) expected_size += lodepng_get_raw_size_idat((*w + 1) >> 2, (*h + 3) >> 2, bpp); expected_size += lodepng_get_raw_size_idat((*w + 1) >> 1, (*h + 1) >> 2, bpp); if(*w > 1) expected_size += lodepng_get_raw_size_idat((*w + 0) >> 1, (*h + 1) >> 1, bpp); expected_size += lodepng_get_raw_size_idat((*w + 0), (*h + 0) >> 1, bpp); } state->error = zlib_decompress(&scanlines, &scanlines_size, expected_size, idat, idatsize, &state->decoder.zlibsettings); } if(!state->error && scanlines_size != expected_size) state->error = 91; /*decompressed size doesn't match prediction*/ lodepng_free(idat); if(!state->error) { outsize = lodepng_get_raw_size(*w, *h, &state->info_png.color); *out = (unsigned char*)lodepng_malloc(outsize); if(!*out) state->error = 83; /*alloc fail*/ } if(!state->error) { lodepng_memset(*out, 0, outsize); state->error = postProcessScanlines(*out, scanlines, *w, *h, &state->info_png); } lodepng_free(scanlines); } unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize) { *out = 0; decodeGeneric(out, w, h, state, in, insize); if(state->error) return state->error; if(!state->decoder.color_convert || lodepng_color_mode_equal(&state->info_raw, &state->info_png.color)) { /*same color type, no copying or converting of data needed*/ /*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype the raw image has to the end user*/ if(!state->decoder.color_convert) { state->error = lodepng_color_mode_copy(&state->info_raw, &state->info_png.color); if(state->error) return state->error; } } else { /*color conversion needed*/ unsigned char* data = *out; size_t outsize; /*TODO: check if this works according to the statement in the documentation: "The converter can convert from grayscale input color type, to 8-bit grayscale or grayscale with alpha"*/ if(!(state->info_raw.colortype == LCT_RGB || state->info_raw.colortype == LCT_RGBA) && !(state->info_raw.bitdepth == 8)) { return 56; /*unsupported color mode conversion*/ } outsize = lodepng_get_raw_size(*w, *h, &state->info_raw); *out = (unsigned char*)lodepng_malloc(outsize); if(!(*out)) { state->error = 83; /*alloc fail*/ } else state->error = lodepng_convert(*out, data, &state->info_raw, &state->info_png.color, *w, *h); lodepng_free(data); } return state->error; } unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize, LodePNGColorType colortype, unsigned bitdepth) { unsigned error; LodePNGState state; lodepng_state_init(&state); state.info_raw.colortype = colortype; state.info_raw.bitdepth = bitdepth; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*disable reading things that this function doesn't output*/ state.decoder.read_text_chunks = 0; state.decoder.remember_unknown_chunks = 0; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ error = lodepng_decode(out, w, h, &state, in, insize); lodepng_state_cleanup(&state); return error; } unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) { return lodepng_decode_memory(out, w, h, in, insize, LCT_RGBA, 8); } unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) { return lodepng_decode_memory(out, w, h, in, insize, LCT_RGB, 8); } #ifdef LODEPNG_COMPILE_DISK unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename, LodePNGColorType colortype, unsigned bitdepth) { unsigned char* buffer = 0; size_t buffersize; unsigned error; /* safe output values in case error happens */ *out = 0; *w = *h = 0; error = lodepng_load_file(&buffer, &buffersize, filename); if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth); lodepng_free(buffer); return error; } unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) { return lodepng_decode_file(out, w, h, filename, LCT_RGBA, 8); } unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) { return lodepng_decode_file(out, w, h, filename, LCT_RGB, 8); } #endif /*LODEPNG_COMPILE_DISK*/ void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings) { settings->color_convert = 1; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS settings->read_text_chunks = 1; settings->remember_unknown_chunks = 0; settings->max_text_size = 16777216; settings->max_icc_size = 16777216; /* 16MB is much more than enough for any reasonable ICC profile */ #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ settings->ignore_crc = 0; settings->ignore_critical = 0; settings->ignore_end = 0; lodepng_decompress_settings_init(&settings->zlibsettings); } #endif /*LODEPNG_COMPILE_DECODER*/ #if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) void lodepng_state_init(LodePNGState* state) { #ifdef LODEPNG_COMPILE_DECODER lodepng_decoder_settings_init(&state->decoder); #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER lodepng_encoder_settings_init(&state->encoder); #endif /*LODEPNG_COMPILE_ENCODER*/ lodepng_color_mode_init(&state->info_raw); lodepng_info_init(&state->info_png); state->error = 1; } void lodepng_state_cleanup(LodePNGState* state) { lodepng_color_mode_cleanup(&state->info_raw); lodepng_info_cleanup(&state->info_png); } unsigned lodepng_state_copy(LodePNGState* dest, const LodePNGState* source) { lodepng_state_cleanup(dest); *dest = *source; lodepng_color_mode_init(&dest->info_raw); lodepng_info_init(&dest->info_png); dest->error = lodepng_color_mode_copy(&dest->info_raw, &source->info_raw); if(dest->error) return dest->error; dest->error = lodepng_info_copy(&dest->info_png, &source->info_png); return dest->error; } #endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */ #ifdef LODEPNG_COMPILE_ENCODER /* ////////////////////////////////////////////////////////////////////////// */ /* / PNG Encoder / */ /* ////////////////////////////////////////////////////////////////////////// */ static unsigned writeSignature(ucvector* out) { size_t pos = out->size; const unsigned char signature[] = {137, 80, 78, 71, 13, 10, 26, 10}; /*8 bytes PNG signature, aka the magic bytes*/ if(!ucvector_resize(out, out->size + 8)) return 83; /*alloc fail*/ lodepng_memcpy(out->data + pos, signature, 8); return 0; } static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method) { unsigned char *chunk, *data; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 13, "IHDR")); data = chunk + 8; lodepng_set32bitInt(data + 0, w); /*width*/ lodepng_set32bitInt(data + 4, h); /*height*/ data[8] = (unsigned char)bitdepth; /*bit depth*/ data[9] = (unsigned char)colortype; /*color type*/ data[10] = 0; /*compression method*/ data[11] = 0; /*filter method*/ data[12] = interlace_method; /*interlace method*/ lodepng_chunk_generate_crc(chunk); return 0; } /* only adds the chunk if needed (there is a key or palette with alpha) */ static unsigned addChunk_PLTE(ucvector* out, const LodePNGColorMode* info) { unsigned char* chunk; size_t i, j = 8; if(info->palettesize == 0 || info->palettesize > 256) { return 68; /*invalid palette size, it is only allowed to be 1-256*/ } CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, info->palettesize * 3, "PLTE")); for(i = 0; i != info->palettesize; ++i) { /*add all channels except alpha channel*/ chunk[j++] = info->palette[i * 4 + 0]; chunk[j++] = info->palette[i * 4 + 1]; chunk[j++] = info->palette[i * 4 + 2]; } lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_tRNS(ucvector* out, const LodePNGColorMode* info) { unsigned char* chunk = 0; if(info->colortype == LCT_PALETTE) { size_t i, amount = info->palettesize; /*the tail of palette values that all have 255 as alpha, does not have to be encoded*/ for(i = info->palettesize; i != 0; --i) { if(info->palette[4 * (i - 1) + 3] != 255) break; --amount; } if(amount) { CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, amount, "tRNS")); /*add the alpha channel values from the palette*/ for(i = 0; i != amount; ++i) chunk[8 + i] = info->palette[4 * i + 3]; } } else if(info->colortype == LCT_GREY) { if(info->key_defined) { CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "tRNS")); chunk[8] = (unsigned char)(info->key_r >> 8); chunk[9] = (unsigned char)(info->key_r & 255); } } else if(info->colortype == LCT_RGB) { if(info->key_defined) { CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "tRNS")); chunk[8] = (unsigned char)(info->key_r >> 8); chunk[9] = (unsigned char)(info->key_r & 255); chunk[10] = (unsigned char)(info->key_g >> 8); chunk[11] = (unsigned char)(info->key_g & 255); chunk[12] = (unsigned char)(info->key_b >> 8); chunk[13] = (unsigned char)(info->key_b & 255); } } if(chunk) lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_IDAT(ucvector* out, const unsigned char* data, size_t datasize, const LodePNGCompressSettings* zlibsettings) { unsigned error = 0; unsigned char* zlib = 0; size_t pos = 0; size_t zlibsize = 0; /* max chunk length allowed by the specification is 2147483647 bytes */ const size_t max_chunk_length = 2147483647u; error = zlib_compress(&zlib, &zlibsize, data, datasize, zlibsettings); while(!error) { if(zlibsize - pos > max_chunk_length) { error = lodepng_chunk_createv(out, max_chunk_length, "IDAT", zlib + pos); pos += max_chunk_length; } else { error = lodepng_chunk_createv(out, zlibsize - pos, "IDAT", zlib + pos); break; } } lodepng_free(zlib); return error; } static unsigned addChunk_IEND(ucvector* out) { return lodepng_chunk_createv(out, 0, "IEND", 0); } #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS static unsigned addChunk_tEXt(ucvector* out, const char* keyword, const char* textstring) { unsigned char* chunk = 0; size_t keysize = lodepng_strlen(keyword), textsize = lodepng_strlen(textstring); size_t size = keysize + 1 + textsize; if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, size, "tEXt")); lodepng_memcpy(chunk + 8, keyword, keysize); chunk[8 + keysize] = 0; /*null termination char*/ lodepng_memcpy(chunk + 9 + keysize, textstring, textsize); lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_zTXt(ucvector* out, const char* keyword, const char* textstring, const LodePNGCompressSettings* zlibsettings) { unsigned error = 0; unsigned char* chunk = 0; unsigned char* compressed = 0; size_t compressedsize = 0; size_t textsize = lodepng_strlen(textstring); size_t keysize = lodepng_strlen(keyword); if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ error = zlib_compress(&compressed, &compressedsize, (const unsigned char*)textstring, textsize, zlibsettings); if(!error) { size_t size = keysize + 2 + compressedsize; error = lodepng_chunk_init(&chunk, out, size, "zTXt"); } if(!error) { lodepng_memcpy(chunk + 8, keyword, keysize); chunk[8 + keysize] = 0; /*null termination char*/ chunk[9 + keysize] = 0; /*compression method: 0*/ lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize); lodepng_chunk_generate_crc(chunk); } lodepng_free(compressed); return error; } static unsigned addChunk_iTXt(ucvector* out, unsigned compress, const char* keyword, const char* langtag, const char* transkey, const char* textstring, const LodePNGCompressSettings* zlibsettings) { unsigned error = 0; unsigned char* chunk = 0; unsigned char* compressed = 0; size_t compressedsize = 0; size_t textsize = lodepng_strlen(textstring); size_t keysize = lodepng_strlen(keyword), langsize = lodepng_strlen(langtag), transsize = lodepng_strlen(transkey); if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ if(compress) { error = zlib_compress(&compressed, &compressedsize, (const unsigned char*)textstring, textsize, zlibsettings); } if(!error) { size_t size = keysize + 3 + langsize + 1 + transsize + 1 + (compress ? compressedsize : textsize); error = lodepng_chunk_init(&chunk, out, size, "iTXt"); } if(!error) { size_t pos = 8; lodepng_memcpy(chunk + pos, keyword, keysize); pos += keysize; chunk[pos++] = 0; /*null termination char*/ chunk[pos++] = (compress ? 1 : 0); /*compression flag*/ chunk[pos++] = 0; /*compression method: 0*/ lodepng_memcpy(chunk + pos, langtag, langsize); pos += langsize; chunk[pos++] = 0; /*null termination char*/ lodepng_memcpy(chunk + pos, transkey, transsize); pos += transsize; chunk[pos++] = 0; /*null termination char*/ if(compress) { lodepng_memcpy(chunk + pos, compressed, compressedsize); } else { lodepng_memcpy(chunk + pos, textstring, textsize); } lodepng_chunk_generate_crc(chunk); } lodepng_free(compressed); return error; } static unsigned addChunk_bKGD(ucvector* out, const LodePNGInfo* info) { unsigned char* chunk = 0; if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) { CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "bKGD")); chunk[8] = (unsigned char)(info->background_r >> 8); chunk[9] = (unsigned char)(info->background_r & 255); } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) { CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "bKGD")); chunk[8] = (unsigned char)(info->background_r >> 8); chunk[9] = (unsigned char)(info->background_r & 255); chunk[10] = (unsigned char)(info->background_g >> 8); chunk[11] = (unsigned char)(info->background_g & 255); chunk[12] = (unsigned char)(info->background_b >> 8); chunk[13] = (unsigned char)(info->background_b & 255); } else if(info->color.colortype == LCT_PALETTE) { CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 1, "bKGD")); chunk[8] = (unsigned char)(info->background_r & 255); /*palette index*/ } if(chunk) lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_tIME(ucvector* out, const LodePNGTime* time) { unsigned char* chunk; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 7, "tIME")); chunk[8] = (unsigned char)(time->year >> 8); chunk[9] = (unsigned char)(time->year & 255); chunk[10] = (unsigned char)time->month; chunk[11] = (unsigned char)time->day; chunk[12] = (unsigned char)time->hour; chunk[13] = (unsigned char)time->minute; chunk[14] = (unsigned char)time->second; lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_pHYs(ucvector* out, const LodePNGInfo* info) { unsigned char* chunk; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 9, "pHYs")); lodepng_set32bitInt(chunk + 8, info->phys_x); lodepng_set32bitInt(chunk + 12, info->phys_y); chunk[16] = info->phys_unit; lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_gAMA(ucvector* out, const LodePNGInfo* info) { unsigned char* chunk; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "gAMA")); lodepng_set32bitInt(chunk + 8, info->gama_gamma); lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_cHRM(ucvector* out, const LodePNGInfo* info) { unsigned char* chunk; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 32, "cHRM")); lodepng_set32bitInt(chunk + 8, info->chrm_white_x); lodepng_set32bitInt(chunk + 12, info->chrm_white_y); lodepng_set32bitInt(chunk + 16, info->chrm_red_x); lodepng_set32bitInt(chunk + 20, info->chrm_red_y); lodepng_set32bitInt(chunk + 24, info->chrm_green_x); lodepng_set32bitInt(chunk + 28, info->chrm_green_y); lodepng_set32bitInt(chunk + 32, info->chrm_blue_x); lodepng_set32bitInt(chunk + 36, info->chrm_blue_y); lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_sRGB(ucvector* out, const LodePNGInfo* info) { unsigned char data = info->srgb_intent; return lodepng_chunk_createv(out, 1, "sRGB", &data); } static unsigned addChunk_iCCP(ucvector* out, const LodePNGInfo* info, const LodePNGCompressSettings* zlibsettings) { unsigned error = 0; unsigned char* chunk = 0; unsigned char* compressed = 0; size_t compressedsize = 0; size_t keysize = lodepng_strlen(info->iccp_name); if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ error = zlib_compress(&compressed, &compressedsize, info->iccp_profile, info->iccp_profile_size, zlibsettings); if(!error) { size_t size = keysize + 2 + compressedsize; error = lodepng_chunk_init(&chunk, out, size, "iCCP"); } if(!error) { lodepng_memcpy(chunk + 8, info->iccp_name, keysize); chunk[8 + keysize] = 0; /*null termination char*/ chunk[9 + keysize] = 0; /*compression method: 0*/ lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize); lodepng_chunk_generate_crc(chunk); } lodepng_free(compressed); return error; } static unsigned addChunk_cICP(ucvector* out, const LodePNGInfo* info) { unsigned char* chunk; /* Allow up to 255 since they are bytes. The ITU-R-BT.709 spec has a more restricted set of valid values for each field, but that's up to the error handling of a CICP library, not the PNG encoding/decoding, to manage. */ if(info->cicp_color_primaries > 255) return 116; if(info->cicp_transfer_function > 255) return 116; if(info->cicp_matrix_coefficients > 255) return 116; if(info->cicp_video_full_range_flag > 255) return 116; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "cICP")); chunk[8 + 0] = (unsigned char)info->cicp_color_primaries; chunk[8 + 1] = (unsigned char)info->cicp_transfer_function; chunk[8 + 2] = (unsigned char)info->cicp_matrix_coefficients; chunk[8 + 3] = (unsigned char)info->cicp_video_full_range_flag; lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_mDCV(ucvector* out, const LodePNGInfo* info) { unsigned char* chunk; /* Allow up to 65535 since they are 16-bit ints. */ if(info->mdcv_red_x > 65535) return 118; if(info->mdcv_red_y > 65535) return 118; if(info->mdcv_green_x > 65535) return 118; if(info->mdcv_green_y > 65535) return 118; if(info->mdcv_blue_x > 65535) return 118; if(info->mdcv_blue_y > 65535) return 118; if(info->mdcv_white_x > 65535) return 118; if(info->mdcv_white_y > 65535) return 118; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 24, "mDCV")); chunk[8 + 0] = (unsigned char)((info->mdcv_red_x) >> 8u); chunk[8 + 1] = (unsigned char)(info->mdcv_red_x); chunk[8 + 2] = (unsigned char)((info->mdcv_red_y) >> 8u); chunk[8 + 3] = (unsigned char)(info->mdcv_red_y); chunk[8 + 4] = (unsigned char)((info->mdcv_green_x) >> 8u); chunk[8 + 5] = (unsigned char)(info->mdcv_green_x); chunk[8 + 6] = (unsigned char)((info->mdcv_green_y) >> 8u); chunk[8 + 7] = (unsigned char)(info->mdcv_green_y); chunk[8 + 8] = (unsigned char)((info->mdcv_blue_x) >> 8u); chunk[8 + 9] = (unsigned char)(info->mdcv_blue_x); chunk[8 + 10] = (unsigned char)((info->mdcv_blue_y) >> 8u); chunk[8 + 11] = (unsigned char)(info->mdcv_blue_y); chunk[8 + 12] = (unsigned char)((info->mdcv_white_x) >> 8u); chunk[8 + 13] = (unsigned char)(info->mdcv_white_x); chunk[8 + 14] = (unsigned char)((info->mdcv_white_y) >> 8u); chunk[8 + 15] = (unsigned char)(info->mdcv_white_y); lodepng_set32bitInt(chunk + 8 + 16, info->mdcv_max_luminance); lodepng_set32bitInt(chunk + 8 + 20, info->mdcv_min_luminance); lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_cLLI(ucvector* out, const LodePNGInfo* info) { unsigned char* chunk; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 8, "cLLI")); lodepng_set32bitInt(chunk + 8 + 0, info->clli_max_cll); lodepng_set32bitInt(chunk + 8 + 4, info->clli_max_fall); lodepng_chunk_generate_crc(chunk); return 0; } static unsigned addChunk_eXIf(ucvector* out, const LodePNGInfo* info) { return lodepng_chunk_createv(out, info->exif_size, "eXIf", info->exif); } static unsigned addChunk_sBIT(ucvector* out, const LodePNGInfo* info) { unsigned bitdepth = (info->color.colortype == LCT_PALETTE) ? 8 : info->color.bitdepth; unsigned char* chunk = 0; if(info->color.colortype == LCT_GREY) { if(info->sbit_r == 0 || info->sbit_r > bitdepth) return 115; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 1, "sBIT")); chunk[8] = info->sbit_r; } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_PALETTE) { if(info->sbit_r == 0 || info->sbit_g == 0 || info->sbit_b == 0) return 115; if(info->sbit_r > bitdepth || info->sbit_g > bitdepth || info->sbit_b > bitdepth) return 115; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 3, "sBIT")); chunk[8] = info->sbit_r; chunk[9] = info->sbit_g; chunk[10] = info->sbit_b; } else if(info->color.colortype == LCT_GREY_ALPHA) { if(info->sbit_r == 0 || info->sbit_a == 0) return 115; if(info->sbit_r > bitdepth || info->sbit_a > bitdepth) return 115; CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "sBIT")); chunk[8] = info->sbit_r; chunk[9] = info->sbit_a; } else if(info->color.colortype == LCT_RGBA) { if(info->sbit_r == 0 || info->sbit_g == 0 || info->sbit_b == 0 || info->sbit_a == 0 || info->sbit_r > bitdepth || info->sbit_g > bitdepth || info->sbit_b > bitdepth || info->sbit_a > bitdepth) { return 115; } CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "sBIT")); chunk[8] = info->sbit_r; chunk[9] = info->sbit_g; chunk[10] = info->sbit_b; chunk[11] = info->sbit_a; } if(chunk) lodepng_chunk_generate_crc(chunk); return 0; } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ static void filterScanline(unsigned char* out, const unsigned char* scanline, const unsigned char* prevline, size_t length, size_t bytewidth, unsigned char filterType) { size_t i; switch(filterType) { case 0: /*None*/ for(i = 0; i != length; ++i) out[i] = scanline[i]; break; case 1: /*Sub*/ for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - scanline[i - bytewidth]; break; case 2: /*Up*/ if(prevline) { for(i = 0; i != length; ++i) out[i] = scanline[i] - prevline[i]; } else { for(i = 0; i != length; ++i) out[i] = scanline[i]; } break; case 3: /*Average*/ if(prevline) { for(i = 0; i != bytewidth; ++i) out[i] = scanline[i] - (prevline[i] >> 1); for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) >> 1); } else { for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - (scanline[i - bytewidth] >> 1); } break; case 4: /*Paeth*/ if(prevline) { /*paethPredictor(0, prevline[i], 0) is always prevline[i]*/ for(i = 0; i != bytewidth; ++i) out[i] = (scanline[i] - prevline[i]); for(i = bytewidth; i < length; ++i) { out[i] = (scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth])); } } else { for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; /*paethPredictor(scanline[i - bytewidth], 0, 0) is always scanline[i - bytewidth]*/ for(i = bytewidth; i < length; ++i) out[i] = (scanline[i] - scanline[i - bytewidth]); } break; default: return; /*invalid filter type given*/ } } static size_t sumUnsignedBytes(const unsigned char* data, size_t length) { size_t sum = 0; #if LODEPNG_PDVZIP_SSE2 { const __m128i zero = _mm_setzero_si128(); while(length >= 16) { unsigned long long partial[2]; const __m128i bytes = _mm_loadu_si128((const __m128i*)data); const __m128i sad = _mm_sad_epu8(bytes, zero); _mm_storeu_si128((__m128i*)partial, sad); sum += (size_t)partial[0] + (size_t)partial[1]; data += 16; length -= 16; } } #endif while(length--) sum += *data++; return sum; } static size_t sumFilteredAbsBytes(const unsigned char* data, size_t length) { size_t sum = 0; #if LODEPNG_PDVZIP_SSE2 { const __m128i zero = _mm_setzero_si128(); const __m128i all_ones = _mm_cmpeq_epi8(zero, zero); while(length >= 16) { unsigned long long partial[2]; const __m128i bytes = _mm_loadu_si128((const __m128i*)data); const __m128i inverted = _mm_xor_si128(bytes, all_ones); const __m128i magnitudes = _mm_min_epu8(bytes, inverted); const __m128i sad = _mm_sad_epu8(magnitudes, zero); _mm_storeu_si128((__m128i*)partial, sad); sum += (size_t)partial[0] + (size_t)partial[1]; data += 16; length -= 16; } } #endif while(length--) { unsigned char s = *data++; sum += s < 128 ? s : (255U - s); } return sum; } /* integer binary logarithm, max return value is 31 */ static size_t ilog2(size_t i) { size_t result = 0; if(i >= 65536) { result += 16; i >>= 16; } if(i >= 256) { result += 8; i >>= 8; } if(i >= 16) { result += 4; i >>= 4; } if(i >= 4) { result += 2; i >>= 2; } if(i >= 2) { result += 1; /*i >>= 1;*/ } return result; } /* integer approximation for i * log2(i), helper function for LFS_ENTROPY */ static size_t ilog2i(size_t i) { size_t l; if(i == 0) return 0; l = ilog2(i); /* approximate i*log2(i): l is integer logarithm, ((i - (1u << l)) << 1u) linearly approximates the missing fractional part multiplied by i */ return i * l + ((i - (((size_t)1) << l)) << 1u); } static unsigned filter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, const LodePNGColorMode* color, const LodePNGEncoderSettings* settings) { /* For PNG filter method 0 out must be a buffer with as size: h + (w * h * bpp + 7u) / 8u, because there are the scanlines with 1 extra byte per scanline */ unsigned bpp = lodepng_get_bpp(color); /*the width of a scanline in bytes, not including the filter type*/ size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u; /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/ size_t bytewidth = (bpp + 7u) / 8u; const unsigned char* prevline = 0; unsigned x, y; unsigned error = 0; LodePNGFilterStrategy strategy = settings->filter_strategy; if(settings->filter_palette_zero && (color->colortype == LCT_PALETTE || color->bitdepth < 8)) { /*if the filter_palette_zero setting is enabled, override the filter strategy with zero for all scanlines for palette and less-than-8-bitdepth images*/ strategy = LFS_ZERO; } if(bpp == 0) return 31; /*error: invalid color type*/ if(strategy >= LFS_ZERO && strategy <= LFS_FOUR) { unsigned char type = (unsigned char)strategy; for(y = 0; y != h; ++y) { size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ size_t inindex = linebytes * y; out[outindex] = type; /*filter type byte*/ filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type); prevline = &in[inindex]; } } else if(strategy == LFS_MINSUM) { /*adaptive filtering: independently for each row, try all five filter types and select the one that produces the smallest sum of absolute values per row.*/ unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ size_t smallest = 0; unsigned char type, bestType = 0; for(type = 0; type != 5; ++type) { attempt[type] = (unsigned char*)lodepng_malloc(linebytes); if(!attempt[type]) error = 83; /*alloc fail*/ } if(!error) { for(y = 0; y != h; ++y) { /*try the 5 filter types*/ for(type = 0; type != 5; ++type) { size_t sum = 0; filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); /*calculate the sum of the result*/ if(type == 0) { sum = sumUnsignedBytes(attempt[type], linebytes); } else { /*For differences, each byte should be treated as signed, values above 127 are negative (converted to signed char). Filtertype 0 isn't a difference though, so use unsigned there. This means filtertype 0 is almost never chosen, but that is justified.*/ sum = sumFilteredAbsBytes(attempt[type], linebytes); } /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/ if(type == 0 || sum < smallest) { bestType = type; smallest = sum; } } prevline = &in[y * linebytes]; /*now fill the out values*/ out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/ for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x]; } } for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); } else if(strategy == LFS_ENTROPY) { unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ size_t bestSum = 0; unsigned type, bestType = 0; unsigned count[256]; for(type = 0; type != 5; ++type) { attempt[type] = (unsigned char*)lodepng_malloc(linebytes); if(!attempt[type]) error = 83; /*alloc fail*/ } if(!error) { for(y = 0; y != h; ++y) { /*try the 5 filter types*/ for(type = 0; type != 5; ++type) { size_t sum = 0; filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); lodepng_memset(count, 0, 256 * sizeof(*count)); for(x = 0; x != linebytes; ++x) ++count[attempt[type][x]]; ++count[type]; /*the filter type itself is part of the scanline*/ for(x = 0; x != 256; ++x) { sum += ilog2i(count[x]); } /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/ if(type == 0 || sum > bestSum) { bestType = type; bestSum = sum; } } prevline = &in[y * linebytes]; /*now fill the out values*/ out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/ for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x]; } } for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); } else if(strategy == LFS_PREDEFINED) { for(y = 0; y != h; ++y) { size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ size_t inindex = linebytes * y; unsigned char type = settings->predefined_filters[y]; out[outindex] = type; /*filter type byte*/ filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type); prevline = &in[inindex]; } } else if(strategy == LFS_BRUTE_FORCE) { /*brute force filter chooser. deflate the scanline after every filter attempt to see which one deflates best. This is very slow and gives only slightly smaller, sometimes even larger, result*/ size_t size[5]; unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ size_t smallest = 0; unsigned type = 0, bestType = 0; unsigned char* dummy; LodePNGCompressSettings zlibsettings; lodepng_memcpy(&zlibsettings, &settings->zlibsettings, sizeof(LodePNGCompressSettings)); /*use fixed tree on the attempts so that the tree is not adapted to the filtertype on purpose, to simulate the true case where the tree is the same for the whole image. Sometimes it gives better result with dynamic tree anyway. Using the fixed tree sometimes gives worse, but in rare cases better compression. It does make this a bit less slow, so it's worth doing this.*/ zlibsettings.btype = 1; /*a custom encoder likely doesn't read the btype setting and is optimized for complete PNG images only, so disable it*/ zlibsettings.custom_zlib = 0; zlibsettings.custom_deflate = 0; for(type = 0; type != 5; ++type) { attempt[type] = (unsigned char*)lodepng_malloc(linebytes); if(!attempt[type]) error = 83; /*alloc fail*/ } if(!error) { for(y = 0; y != h; ++y) /*try the 5 filter types*/ { for(type = 0; type != 5; ++type) { unsigned testsize = (unsigned)linebytes; /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/ filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); size[type] = 0; dummy = 0; zlib_compress(&dummy, &size[type], attempt[type], testsize, &zlibsettings); lodepng_free(dummy); /*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/ if(type == 0 || size[type] < smallest) { bestType = type; smallest = size[type]; } } prevline = &in[y * linebytes]; out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/ for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x]; } } for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); } else return 88; /* unknown filter strategy */ return error; } static void addPaddingBits(unsigned char* out, const unsigned char* in, size_t olinebits, size_t ilinebits, unsigned h) { /*The opposite of the removePaddingBits function olinebits must be >= ilinebits*/ unsigned y; size_t diff = olinebits - ilinebits; size_t obp = 0, ibp = 0; /*bit pointers*/ for(y = 0; y != h; ++y) { size_t x; for(x = 0; x < ilinebits; ++x) { unsigned char bit = readBitFromReversedStream(&ibp, in); setBitOfReversedStream(&obp, out, bit); } /*obp += diff; --> no, fill in some value in the padding bits too, to avoid "Use of uninitialised value of size ###" warning from valgrind*/ for(x = 0; x != diff; ++x) setBitOfReversedStream(&obp, out, 0); } } /* in: non-interlaced image with size w*h out: the same pixels, but re-ordered according to PNG's Adam7 interlacing, with no padding bits between scanlines, but between reduced images so that each reduced image starts at a byte. bpp: bits per pixel there are no padding bits, not between scanlines, not between reduced images in has the following size in bits: w * h * bpp. out is possibly bigger due to padding bits between reduced images NOTE: comments about padding bits are only relevant if bpp < 8 */ static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8]; unsigned i; Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); if(bpp >= 8) { for(i = 0; i != 7; ++i) { unsigned x, y, b; size_t bytewidth = bpp / 8u; for(y = 0; y < passh[i]; ++y) for(x = 0; x < passw[i]; ++x) { size_t pixelinstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth; size_t pixeloutstart = passstart[i] + (y * passw[i] + x) * bytewidth; for(b = 0; b < bytewidth; ++b) { out[pixeloutstart + b] = in[pixelinstart + b]; } } } } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ { for(i = 0; i != 7; ++i) { unsigned x, y, b; unsigned ilinebits = bpp * passw[i]; unsigned olinebits = bpp * w; size_t obp, ibp; /*bit pointers (for out and in buffer)*/ for(y = 0; y < passh[i]; ++y) for(x = 0; x < passw[i]; ++x) { ibp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp; obp = (8 * passstart[i]) + (y * ilinebits + x * bpp); for(b = 0; b < bpp; ++b) { unsigned char bit = readBitFromReversedStream(&ibp, in); setBitOfReversedStream(&obp, out, bit); } } } } } /*out must be buffer big enough to contain uncompressed IDAT chunk data, and in must contain the full image. return value is error**/ static unsigned preProcessScanlines(unsigned char** out, size_t* outsize, const unsigned char* in, unsigned w, unsigned h, const LodePNGInfo* info_png, const LodePNGEncoderSettings* settings) { /* This function converts the pure 2D image with the PNG's colortype, into filtered-padded-interlaced data. Steps: *) if no Adam7: 1) add padding bits (= possible extra bits per scanline if bpp < 8) 2) filter *) if adam7: 1) Adam7_interlace 2) 7x add padding bits 3) 7x filter */ size_t bpp = lodepng_get_bpp(&info_png->color); unsigned error = 0; if(info_png->interlace_method == 0) { /*image size plus an extra byte per scanline + possible padding bits*/ *outsize = (size_t)h + ((size_t)h * (((size_t)w * bpp + 7u) / 8u)); *out = (unsigned char*)lodepng_malloc(*outsize); if(!(*out) && (*outsize)) error = 83; /*alloc fail*/ if(!error) { /*non multiple of 8 bits per scanline, padding bits needed per scanline*/ if(bpp < 8 && (size_t)w * bpp != (((size_t)w * bpp + 7u) / 8u) * 8u) { unsigned char* padded = (unsigned char*)lodepng_malloc(h * ((w * bpp + 7u) / 8u)); if(!padded) error = 83; /*alloc fail*/ if(!error) { addPaddingBits(padded, in, (((size_t)w * bpp + 7u) / 8u) * 8u, (size_t)w * bpp, h); error = filter(*out, padded, w, h, &info_png->color, settings); } lodepng_free(padded); } else { /*we can immediately filter into the out buffer, no other steps needed*/ error = filter(*out, in, w, h, &info_png->color, settings); } } } else /*interlace_method is 1 (Adam7)*/ { unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8]; unsigned char* adam7; Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, (unsigned)bpp); *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/ *out = (unsigned char*)lodepng_malloc(*outsize); if(!(*out)) error = 83; /*alloc fail*/ adam7 = (unsigned char*)lodepng_malloc(passstart[7]); if(!adam7 && passstart[7]) error = 83; /*alloc fail*/ if(!error) { unsigned i; Adam7_interlace(adam7, in, w, h, (unsigned)bpp); for(i = 0; i != 7; ++i) { if(bpp < 8) { unsigned char* padded = (unsigned char*)lodepng_malloc(padded_passstart[i + 1] - padded_passstart[i]); if(!padded) ERROR_BREAK(83); /*alloc fail*/ addPaddingBits(padded, &adam7[passstart[i]], (((size_t)passw[i] * bpp + 7u) / 8u) * 8u, (size_t)passw[i] * bpp, passh[i]); error = filter(&(*out)[filter_passstart[i]], padded, passw[i], passh[i], &info_png->color, settings); lodepng_free(padded); } else { error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]], passw[i], passh[i], &info_png->color, settings); } if(error) break; } } lodepng_free(adam7); } return error; } #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS static unsigned addUnknownChunks(ucvector* out, unsigned char* data, size_t datasize) { unsigned char* inchunk = data; while((size_t)(inchunk - data) < datasize) { CERROR_TRY_RETURN(lodepng_chunk_append(&out->data, &out->size, inchunk)); out->allocsize = out->size; /*fix the allocsize again*/ inchunk = lodepng_chunk_next(inchunk, data + datasize); } return 0; } static unsigned isGrayICCProfile(const unsigned char* profile, unsigned size) { /* It is a gray profile if bytes 16-19 are "GRAY", rgb profile if bytes 16-19 are "RGB ". We do not perform any full parsing of the ICC profile here, other than check those 4 bytes to grayscale profile. Other than that, validity of the profile is not checked. This is needed only because the PNG specification requires using a non-gray color model if there is an ICC profile with "RGB " (sadly limiting compression opportunities if the input data is grayscale RGB data), and requires using a gray color model if it is "GRAY". */ if(size < 20) return 0; return profile[16] == 'G' && profile[17] == 'R' && profile[18] == 'A' && profile[19] == 'Y'; } static unsigned isRGBICCProfile(const unsigned char* profile, unsigned size) { /* See comment in isGrayICCProfile*/ if(size < 20) return 0; return profile[16] == 'R' && profile[17] == 'G' && profile[18] == 'B' && profile[19] == ' '; } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ unsigned lodepng_encode(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h, LodePNGState* state) { unsigned char* data = 0; /*uncompressed version of the IDAT chunk data*/ size_t datasize = 0; ucvector outv = ucvector_init(NULL, 0); LodePNGInfo info; const LodePNGInfo* info_png = &state->info_png; LodePNGColorMode auto_color; unsigned error = 0; lodepng_info_init(&info); lodepng_color_mode_init(&auto_color); /*provide some proper output values if error will happen*/ *out = 0; *outsize = 0; /*check input values validity*/ if((info_png->color.colortype == LCT_PALETTE || state->encoder.force_palette) && (info_png->color.palettesize == 0 || info_png->color.palettesize > 256)) { /*this error is returned even if auto_convert is enabled and thus encoder could generate the palette by itself: while allowing this could be possible in theory, it may complicate the code or edge cases, and always requiring to give a palette when setting this color type is a simpler contract*/ error = 68; /*invalid palette size, it is only allowed to be 1-256*/ goto cleanup; } if(state->encoder.zlibsettings.btype > 2) { error = 61; /*error: invalid btype*/ goto cleanup; } if(info_png->interlace_method > 1) { error = 71; /*error: invalid interlace mode*/ goto cleanup; } error = checkColorValidity(info_png->color.colortype, info_png->color.bitdepth); if(error) goto cleanup; /*error: invalid color type given*/ error = checkColorValidity(state->info_raw.colortype, state->info_raw.bitdepth); if(error) goto cleanup; /*error: invalid color type given*/ /* color convert and compute scanline filter types */ CERROR_TRY_RETURN(lodepng_info_copy(&info, &state->info_png)); if(state->encoder.auto_convert) { LodePNGColorStats stats; unsigned allow_convert = 1; lodepng_color_stats_init(&stats); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS if(info_png->iccp_defined && isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) { /*the PNG specification does not allow to use palette with a GRAY ICC profile, even if the palette has only gray colors, so disallow it.*/ stats.allow_palette = 0; } if(info_png->iccp_defined && isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) { /*the PNG specification does not allow to use grayscale color with RGB ICC profile, so disallow gray.*/ stats.allow_greyscale = 0; } #endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */ error = lodepng_compute_color_stats(&stats, image, w, h, &state->info_raw); if(error) goto cleanup; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS if(info_png->background_defined) { /*the background chunk's color must be taken into account as well*/ unsigned r = 0, g = 0, b = 0; LodePNGColorMode mode16 = lodepng_color_mode_make(LCT_RGB, 16); lodepng_convert_rgb(&r, &g, &b, info_png->background_r, info_png->background_g, info_png->background_b, &mode16, &info_png->color); error = lodepng_color_stats_add(&stats, r, g, b, 65535); if(error) goto cleanup; } #endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */ error = auto_choose_color(&auto_color, &state->info_raw, &stats); if(error) goto cleanup; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS if(info_png->sbit_defined) { /*if sbit is defined, due to strict requirements of which sbit values can be present for which color modes, auto_convert can't be done in many cases. However, do support a few cases here. TODO: more conversions may be possible, and it may also be possible to get a more appropriate color type out of auto_choose_color if knowledge about sbit is used beforehand */ unsigned sbit_max = LODEPNG_MAX(LODEPNG_MAX(LODEPNG_MAX(info_png->sbit_r, info_png->sbit_g), info_png->sbit_b), info_png->sbit_a); unsigned equal = (!info_png->sbit_g || info_png->sbit_g == info_png->sbit_r) && (!info_png->sbit_b || info_png->sbit_b == info_png->sbit_r) && (!info_png->sbit_a || info_png->sbit_a == info_png->sbit_r); allow_convert = 0; if(info.color.colortype == LCT_PALETTE && auto_color.colortype == LCT_PALETTE) { /* input and output are palette, and in this case it may happen that palette data is expected to be copied from info_raw into the info_png */ allow_convert = 1; } /*going from 8-bit RGB to palette (or 16-bit as long as sbit_max <= 8) is possible since both are 8-bit RGB for sBIT's purposes*/ if(info.color.colortype == LCT_RGB && auto_color.colortype == LCT_PALETTE && sbit_max <= 8) { allow_convert = 1; } /*going from 8-bit RGBA to palette is also ok but only if sbit_a is exactly 8*/ if(info.color.colortype == LCT_RGBA && auto_color.colortype == LCT_PALETTE && info_png->sbit_a == 8 && sbit_max <= 8) { allow_convert = 1; } /*going from 16-bit RGB(A) to 8-bit RGB(A) is ok if all sbit values are <= 8*/ if((info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA) && info.color.bitdepth == 16 && auto_color.colortype == info.color.colortype && auto_color.bitdepth == 8 && sbit_max <= 8) { allow_convert = 1; } /*going to less channels is ok if all bit values are equal (all possible values in sbit, as well as the chosen bitdepth of the result). Due to how auto_convert works, we already know that auto_color.colortype has less than or equal amount of channels than info.colortype. Palette is not used here. This conversion is not allowed if info_png->sbit_r < auto_color.bitdepth, because specifically for alpha, non-presence of an sbit value heavily implies that alpha's bit depth is equal to the PNG bit depth (rather than the bit depths set in the r, g and b sbit values, by how the PNG specification describes handling tRNS chunk case with sBIT), so be conservative here about ignoring user input.*/ if(info.color.colortype != LCT_PALETTE && auto_color.colortype != LCT_PALETTE && equal && info_png->sbit_r == auto_color.bitdepth) { allow_convert = 1; } } #endif if(state->encoder.force_palette) { if(info.color.colortype != LCT_GREY && info.color.colortype != LCT_GREY_ALPHA && (auto_color.colortype == LCT_GREY || auto_color.colortype == LCT_GREY_ALPHA)) { /*user specifically forced a PLTE palette, so cannot convert to grayscale types because the PNG specification only allows writing a suggested palette in PLTE for truecolor types*/ allow_convert = 0; } } if(allow_convert) { lodepng_color_mode_copy(&info.color, &auto_color); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*also convert the background chunk*/ if(info_png->background_defined) { if(lodepng_convert_rgb(&info.background_r, &info.background_g, &info.background_b, info_png->background_r, info_png->background_g, info_png->background_b, &info.color, &info_png->color)) { error = 104; goto cleanup; } } #endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */ } } #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS if(info_png->iccp_defined) { unsigned gray_icc = isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size); unsigned rgb_icc = isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size); unsigned gray_png = info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA; if(!gray_icc && !rgb_icc) { error = 100; /* Disallowed profile color type for PNG */ goto cleanup; } if(gray_icc != gray_png) { /*Not allowed to use RGB/RGBA/palette with GRAY ICC profile or vice versa, or in case of auto_convert, it wasn't possible to find appropriate model*/ error = state->encoder.auto_convert ? 102 : 101; goto cleanup; } } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ if(!lodepng_color_mode_equal(&state->info_raw, &info.color)) { unsigned char* converted; size_t size = ((size_t)w * (size_t)h * (size_t)lodepng_get_bpp(&info.color) + 7u) / 8u; converted = (unsigned char*)lodepng_malloc(size); if(!converted && size) error = 83; /*alloc fail*/ if(!error) { error = lodepng_convert(converted, image, &info.color, &state->info_raw, w, h); } if(!error) { error = preProcessScanlines(&data, &datasize, converted, w, h, &info, &state->encoder); } lodepng_free(converted); if(error) goto cleanup; } else { error = preProcessScanlines(&data, &datasize, image, w, h, &info, &state->encoder); if(error) goto cleanup; } /* output all PNG chunks */ { #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS size_t i; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /*write signature and chunks*/ error = writeSignature(&outv); if(error) goto cleanup; /*IHDR*/ error = addChunk_IHDR(&outv, w, h, info.color.colortype, info.color.bitdepth, info.interlace_method); if(error) goto cleanup; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*unknown chunks between IHDR and PLTE*/ if(info.unknown_chunks_data[0]) { error = addUnknownChunks(&outv, info.unknown_chunks_data[0], info.unknown_chunks_size[0]); if(error) goto cleanup; } /*color profile chunks must come before PLTE */ if(info.cicp_defined) { error = addChunk_cICP(&outv, &info); if(error) goto cleanup; } if(info.mdcv_defined) { error = addChunk_mDCV(&outv, &info); if(error) goto cleanup; } if(info.clli_defined) { error = addChunk_cLLI(&outv, &info); if(error) goto cleanup; } if(info.iccp_defined) { error = addChunk_iCCP(&outv, &info, &state->encoder.zlibsettings); if(error) goto cleanup; } if(info.srgb_defined) { error = addChunk_sRGB(&outv, &info); if(error) goto cleanup; } if(info.gama_defined) { error = addChunk_gAMA(&outv, &info); if(error) goto cleanup; } if(info.chrm_defined) { error = addChunk_cHRM(&outv, &info); if(error) goto cleanup; } if(info_png->sbit_defined) { error = addChunk_sBIT(&outv, &info); if(error) goto cleanup; } if(info.exif_defined) { error = addChunk_eXIf(&outv, &info); if(error) goto cleanup; } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /*PLTE*/ if(info.color.colortype == LCT_PALETTE) { error = addChunk_PLTE(&outv, &info.color); if(error) goto cleanup; } if(state->encoder.force_palette && (info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA)) { /*force_palette means: write suggested palette for truecolor in PLTE chunk*/ error = addChunk_PLTE(&outv, &info.color); if(error) goto cleanup; } /*tRNS (this will only add if when necessary) */ error = addChunk_tRNS(&outv, &info.color); if(error) goto cleanup; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*bKGD (must come between PLTE and the IDAt chunks*/ if(info.background_defined) { error = addChunk_bKGD(&outv, &info); if(error) goto cleanup; } /*pHYs (must come before the IDAT chunks)*/ if(info.phys_defined) { error = addChunk_pHYs(&outv, &info); if(error) goto cleanup; } /*unknown chunks between PLTE and IDAT*/ if(info.unknown_chunks_data[1]) { error = addUnknownChunks(&outv, info.unknown_chunks_data[1], info.unknown_chunks_size[1]); if(error) goto cleanup; } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /*IDAT (multiple IDAT chunks must be consecutive)*/ error = addChunk_IDAT(&outv, data, datasize, &state->encoder.zlibsettings); if(error) goto cleanup; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*tIME*/ if(info.time_defined) { error = addChunk_tIME(&outv, &info.time); if(error) goto cleanup; } /*tEXt and/or zTXt*/ for(i = 0; i != info.text_num; ++i) { if(lodepng_strlen(info.text_keys[i]) > 79) { error = 66; /*text chunk too large*/ goto cleanup; } if(lodepng_strlen(info.text_keys[i]) < 1) { error = 67; /*text chunk too small*/ goto cleanup; } if(state->encoder.text_compression) { error = addChunk_zTXt(&outv, info.text_keys[i], info.text_strings[i], &state->encoder.zlibsettings); if(error) goto cleanup; } else { error = addChunk_tEXt(&outv, info.text_keys[i], info.text_strings[i]); if(error) goto cleanup; } } /*LodePNG version id in text chunk*/ if(state->encoder.add_id) { unsigned already_added_id_text = 0; for(i = 0; i != info.text_num; ++i) { const char* k = info.text_keys[i]; /* Could use strcmp, but we're not calling or reimplementing this C library function for this use only */ if(k[0] == 'L' && k[1] == 'o' && k[2] == 'd' && k[3] == 'e' && k[4] == 'P' && k[5] == 'N' && k[6] == 'G' && k[7] == '\0') { already_added_id_text = 1; break; } } if(already_added_id_text == 0) { error = addChunk_tEXt(&outv, "LodePNG", LODEPNG_VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/ if(error) goto cleanup; } } /*iTXt*/ for(i = 0; i != info.itext_num; ++i) { if(lodepng_strlen(info.itext_keys[i]) > 79) { error = 66; /*text chunk too large*/ goto cleanup; } if(lodepng_strlen(info.itext_keys[i]) < 1) { error = 67; /*text chunk too small*/ goto cleanup; } error = addChunk_iTXt( &outv, state->encoder.text_compression, info.itext_keys[i], info.itext_langtags[i], info.itext_transkeys[i], info.itext_strings[i], &state->encoder.zlibsettings); if(error) goto cleanup; } /*unknown chunks between IDAT and IEND*/ if(info.unknown_chunks_data[2]) { error = addUnknownChunks(&outv, info.unknown_chunks_data[2], info.unknown_chunks_size[2]); if(error) goto cleanup; } #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ error = addChunk_IEND(&outv); if(error) goto cleanup; } cleanup: lodepng_info_cleanup(&info); lodepng_free(data); lodepng_color_mode_cleanup(&auto_color); /*instead of cleaning the vector up, give it to the output*/ *out = outv.data; *outsize = outv.size; state->error = error; /*TODO: remove this and make input state const*/ return error; } unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { unsigned error; LodePNGState state; lodepng_state_init(&state); state.info_raw.colortype = colortype; state.info_raw.bitdepth = bitdepth; state.info_png.color.colortype = colortype; state.info_png.color.bitdepth = bitdepth; error = lodepng_encode(out, outsize, image, w, h, &state); lodepng_state_cleanup(&state); return error; } unsigned lodepng_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) { return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGBA, 8); } unsigned lodepng_encode24(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) { return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGB, 8); } #ifdef LODEPNG_COMPILE_DISK unsigned lodepng_encode_file(const char* filename, const unsigned char* image, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { unsigned char* buffer; size_t buffersize; unsigned error = lodepng_encode_memory(&buffer, &buffersize, image, w, h, colortype, bitdepth); if(!error) error = lodepng_save_file(buffer, buffersize, filename); lodepng_free(buffer); return error; } unsigned lodepng_encode32_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) { return lodepng_encode_file(filename, image, w, h, LCT_RGBA, 8); } unsigned lodepng_encode24_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) { return lodepng_encode_file(filename, image, w, h, LCT_RGB, 8); } #endif /*LODEPNG_COMPILE_DISK*/ void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings) { lodepng_compress_settings_init(&settings->zlibsettings); settings->filter_palette_zero = 1; settings->filter_strategy = LFS_MINSUM; settings->auto_convert = 1; settings->force_palette = 0; settings->predefined_filters = 0; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS settings->add_id = 0; settings->text_compression = 1; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } #endif /*LODEPNG_COMPILE_ENCODER*/ #endif /*LODEPNG_COMPILE_PNG*/ #ifdef LODEPNG_COMPILE_ERROR_TEXT /* This returns the description of a numerical error code in English. This is also the documentation of all the error codes. */ const char* lodepng_error_text(unsigned code) { switch(code) { case 0: return "no error, everything went ok"; case 1: return "nothing done yet"; /*the Encoder/Decoder has done nothing yet, error checking makes no sense yet*/ case 10: return "end of input memory reached without huffman end code"; /*while huffman decoding*/ case 11: return "error in code tree made it jump outside of huffman tree"; /*while huffman decoding*/ case 13: return "problem while processing dynamic deflate block"; case 14: return "problem while processing dynamic deflate block"; case 15: return "problem while processing dynamic deflate block"; /*this error could happen if there are only 0 or 1 symbols present in the huffman code:*/ case 16: return "invalid code while processing dynamic deflate block"; case 17: return "end of out buffer memory reached while inflating"; case 18: return "invalid distance code while inflating"; case 19: return "end of out buffer memory reached while inflating"; case 20: return "invalid deflate block BTYPE encountered while decoding"; case 21: return "NLEN is not ones complement of LEN in a deflate block"; /*end of out buffer memory reached while inflating: This can happen if the inflated deflate data is longer than the amount of bytes required to fill up all the pixels of the image, given the color depth and image dimensions. Something that doesn't happen in a normal, well encoded, PNG image.*/ case 22: return "end of out buffer memory reached while inflating"; case 23: return "end of in buffer memory reached while inflating"; case 24: return "invalid FCHECK in zlib header"; case 25: return "invalid compression method in zlib header"; case 26: return "FDICT encountered in zlib header while it's not used for PNG"; case 27: return "PNG file is smaller than a PNG header"; /*Checks the magic file header, the first 8 bytes of the PNG file*/ case 28: return "incorrect PNG signature, it's no PNG or corrupted"; case 29: return "first chunk is not the header chunk"; case 30: return "chunk length too large, chunk broken off at end of file"; case 31: return "illegal PNG color type or bpp"; case 32: return "illegal PNG compression method"; case 33: return "illegal PNG filter method"; case 34: return "illegal PNG interlace method"; case 35: return "chunk length of a chunk is too large or the chunk too small"; case 36: return "illegal PNG filter type encountered"; case 37: return "illegal bit depth for this color type given"; case 38: return "the palette is too small or too big"; /*0, or more than 256 colors*/ case 39: return "tRNS chunk before PLTE or has more entries than palette size"; case 40: return "tRNS chunk has wrong size for grayscale image"; case 41: return "tRNS chunk has wrong size for RGB image"; case 42: return "tRNS chunk appeared while it was not allowed for this color type"; case 43: return "bKGD chunk has wrong size for palette image"; case 44: return "bKGD chunk has wrong size for grayscale image"; case 45: return "bKGD chunk has wrong size for RGB image"; case 48: return "empty input buffer given to decoder. Maybe caused by non-existing file?"; case 49: return "jumped past memory while generating dynamic huffman tree"; case 50: return "jumped past memory while generating dynamic huffman tree"; case 51: return "jumped past memory while inflating huffman block"; case 52: return "jumped past memory while inflating"; case 53: return "size of zlib data too small"; case 54: return "repeat symbol in tree while there was no value symbol yet"; /*jumped past tree while generating huffman tree, this could be when the tree will have more leaves than symbols after generating it out of the given lengths. They call this an oversubscribed dynamic bit lengths tree in zlib.*/ case 55: return "jumped past tree while generating huffman tree"; case 56: return "given output image colortype or bitdepth not supported for color conversion"; case 57: return "invalid CRC encountered (checking CRC can be disabled)"; case 58: return "invalid ADLER32 encountered (checking ADLER32 can be disabled)"; case 59: return "requested color conversion not supported"; case 60: return "invalid window size given in the settings of the encoder (must be 0-32768)"; case 61: return "invalid BTYPE given in the settings of the encoder (only 0, 1 and 2 are allowed)"; /*LodePNG leaves the choice of RGB to grayscale conversion formula to the user.*/ case 62: return "conversion from color to grayscale not supported"; /*(2^31-1)*/ case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk"; /*this would result in the inability of a deflated block to ever contain an end code. It must be at least 1.*/ case 64: return "the length of the END symbol 256 in the Huffman tree is 0"; case 66: return "the length of a text chunk keyword given to the encoder is longer than the maximum of 79 bytes"; case 67: return "the length of a text chunk keyword given to the encoder is smaller than the minimum of 1 byte"; case 68: return "tried to encode a PLTE chunk with a palette that has less than 1 or more than 256 colors"; case 69: return "unknown chunk type with 'critical' flag encountered by the decoder"; case 71: return "invalid interlace mode given to encoder (must be 0 or 1)"; case 72: return "while decoding, invalid compression method encountered in zTXt, iTXt or iCCP chunk (it must be 0)"; case 73: return "invalid tIME chunk size"; case 74: return "invalid pHYs chunk size"; /*length could be wrong, or data chopped off*/ case 75: return "no null termination char found while decoding text chunk"; case 76: return "iTXt chunk too short to contain required bytes"; case 77: return "integer overflow in buffer size"; case 78: return "failed to open file for reading"; /*file doesn't exist or couldn't be opened for reading*/ case 79: return "failed to open file for writing"; case 80: return "tried creating a tree of 0 symbols"; case 81: return "lazy matching at pos 0 is impossible"; case 82: return "color conversion to palette requested while a color isn't in palette, or index out of bounds"; case 83: return "memory allocation failed"; case 84: return "given image too small to contain all pixels to be encoded"; case 86: return "impossible offset in lz77 encoding (internal bug)"; case 87: return "must provide custom zlib function pointer if LODEPNG_COMPILE_ZLIB is not defined"; case 88: return "invalid filter strategy given for LodePNGEncoderSettings.filter_strategy"; case 89: return "text chunk keyword too short or long: must have size 1-79"; /*the windowsize in the LodePNGCompressSettings. Requiring POT(==> & instead of %) makes encoding 12% faster.*/ case 90: return "windowsize must be a power of two"; case 91: return "invalid decompressed idat size"; case 92: return "integer overflow due to too many pixels"; case 93: return "zero width or height is invalid"; case 94: return "header chunk must have a size of 13 bytes"; case 95: return "integer overflow with combined idat chunk size"; case 96: return "invalid gAMA chunk size"; case 97: return "invalid cHRM chunk size"; case 98: return "invalid sRGB chunk size"; case 99: return "invalid sRGB rendering intent"; case 100: return "invalid ICC profile color type, the PNG specification only allows RGB or GRAY"; case 101: return "PNG specification does not allow RGB ICC profile on gray color types and vice versa"; case 102: return "not allowed to set grayscale ICC profile with colored pixels by PNG specification"; case 103: return "invalid palette index in bKGD chunk. Maybe it came before PLTE chunk?"; case 104: return "invalid bKGD color while encoding (e.g. palette index out of range)"; case 105: return "integer overflow of bitsize"; case 106: return "PNG file must have PLTE chunk if color type is palette"; case 107: return "color convert from palette mode requested without setting the palette data in it"; case 108: return "tried to add more than 256 values to a palette"; /*this limit can be configured in LodePNGDecompressSettings*/ case 109: return "tried to decompress zlib or deflate data larger than desired max_output_size"; case 110: return "custom zlib or inflate decompression failed"; case 111: return "custom zlib or deflate compression failed"; /*max text size limit can be configured in LodePNGDecoderSettings. This error prevents unreasonable memory consumption when decoding due to impossibly large text sizes.*/ case 112: return "compressed text unreasonably large"; /*max ICC size limit can be configured in LodePNGDecoderSettings. This error prevents unreasonable memory consumption when decoding due to impossibly large ICC profile*/ case 113: return "ICC profile unreasonably large"; case 114: return "sBIT chunk has wrong size for the color type of the image"; case 115: return "sBIT value out of range"; case 116: return "cICP value out of range"; case 117: return "invalid cICP chunk size"; case 118: return "mDCV value out of range"; case 119: return "invalid mDCV chunk size"; case 120: return "invalid cLLI chunk size"; case 121: return "invalid chunk type name: may only contain [a-zA-Z]"; case 122: return "invalid chunk type name: third character must be uppercase"; case 123: return "invalid ICC profile size"; } return "unknown error code"; } #endif /*LODEPNG_COMPILE_ERROR_TEXT*/ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ /* // C++ Wrapper // */ /* ////////////////////////////////////////////////////////////////////////// */ /* ////////////////////////////////////////////////////////////////////////// */ #ifdef LODEPNG_COMPILE_CPP namespace lodepng { #ifdef LODEPNG_COMPILE_DISK /* Resizes the vector to the file size and reads the file into it. Returns error code.*/ static unsigned load_file_(std::vector& buffer, FILE* file) { long size = lodepng_filesize(file); if(size < 0) return 78; buffer.resize((size_t)size); if(size == 0) return 0; /*ok*/ if(fread(&buffer[0], 1, buffer.size(), file) != buffer.size()) return 78; return 0; /*ok*/ } unsigned load_file(std::vector& buffer, const std::string& filename) { unsigned error; FILE* file = fopen(filename.c_str(), "rb"); if(!file) return 78; error = load_file_(buffer, file); fclose(file); return error; } /*write given buffer to the file, overwriting the file, it doesn't append to it.*/ unsigned save_file(const std::vector& buffer, const std::string& filename) { return lodepng_save_file(buffer.empty() ? 0 : &buffer[0], buffer.size(), filename.c_str()); } #endif /* LODEPNG_COMPILE_DISK */ #ifdef LODEPNG_COMPILE_ZLIB #ifdef LODEPNG_COMPILE_DECODER unsigned decompress(std::vector& out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings& settings) { unsigned char* buffer = 0; size_t buffersize = 0; unsigned error = zlib_decompress(&buffer, &buffersize, 0, in, insize, &settings); if(buffer) { out.insert(out.end(), buffer, &buffer[buffersize]); lodepng_free(buffer); } return error; } unsigned decompress(std::vector& out, const std::vector& in, const LodePNGDecompressSettings& settings) { return decompress(out, in.empty() ? 0 : &in[0], in.size(), settings); } #endif /* LODEPNG_COMPILE_DECODER */ #ifdef LODEPNG_COMPILE_ENCODER unsigned compress(std::vector& out, const unsigned char* in, size_t insize, const LodePNGCompressSettings& settings) { unsigned char* buffer = 0; size_t buffersize = 0; unsigned error = zlib_compress(&buffer, &buffersize, in, insize, &settings); if(buffer) { out.insert(out.end(), buffer, &buffer[buffersize]); lodepng_free(buffer); } return error; } unsigned compress(std::vector& out, const std::vector& in, const LodePNGCompressSettings& settings) { return compress(out, in.empty() ? 0 : &in[0], in.size(), settings); } #endif /* LODEPNG_COMPILE_ENCODER */ #endif /* LODEPNG_COMPILE_ZLIB */ #ifdef LODEPNG_COMPILE_PNG State::State() { lodepng_state_init(this); } State::State(const State& other) { lodepng_state_init(this); lodepng_state_copy(this, &other); } State::~State() { lodepng_state_cleanup(this); } State& State::operator=(const State& other) { lodepng_state_copy(this, &other); return *this; } #ifdef LODEPNG_COMPILE_DECODER unsigned decode(std::vector& out, unsigned& w, unsigned& h, const unsigned char* in, size_t insize, LodePNGColorType colortype, unsigned bitdepth) { unsigned char* buffer = 0; unsigned error = lodepng_decode_memory(&buffer, &w, &h, in, insize, colortype, bitdepth); if(buffer && !error) { State state; state.info_raw.colortype = colortype; state.info_raw.bitdepth = bitdepth; size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw); out.insert(out.end(), buffer, &buffer[buffersize]); } lodepng_free(buffer); return error; } unsigned decode(std::vector& out, unsigned& w, unsigned& h, const std::vector& in, LodePNGColorType colortype, unsigned bitdepth) { return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colortype, bitdepth); } unsigned decode(std::vector& out, unsigned& w, unsigned& h, State& state, const unsigned char* in, size_t insize) { unsigned char* buffer = NULL; unsigned error = lodepng_decode(&buffer, &w, &h, &state, in, insize); if(buffer && !error) { size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw); out.insert(out.end(), buffer, &buffer[buffersize]); } lodepng_free(buffer); return error; } unsigned decode(std::vector& out, unsigned& w, unsigned& h, State& state, const std::vector& in) { return decode(out, w, h, state, in.empty() ? 0 : &in[0], in.size()); } #ifdef LODEPNG_COMPILE_DISK unsigned decode(std::vector& out, unsigned& w, unsigned& h, const std::string& filename, LodePNGColorType colortype, unsigned bitdepth) { std::vector buffer; /* safe output values in case error happens */ w = h = 0; unsigned error = load_file(buffer, filename); if(error) return error; return decode(out, w, h, buffer, colortype, bitdepth); } #endif /* LODEPNG_COMPILE_DECODER */ #endif /* LODEPNG_COMPILE_DISK */ #ifdef LODEPNG_COMPILE_ENCODER unsigned encode(std::vector& out, const unsigned char* in, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { unsigned char* buffer; size_t buffersize; unsigned error = lodepng_encode_memory(&buffer, &buffersize, in, w, h, colortype, bitdepth); if(buffer) { out.insert(out.end(), buffer, &buffer[buffersize]); lodepng_free(buffer); } return error; } unsigned encode(std::vector& out, const std::vector& in, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84; return encode(out, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth); } unsigned encode(std::vector& out, const unsigned char* in, unsigned w, unsigned h, State& state) { unsigned char* buffer; size_t buffersize; unsigned error = lodepng_encode(&buffer, &buffersize, in, w, h, &state); if(buffer) { out.insert(out.end(), buffer, &buffer[buffersize]); lodepng_free(buffer); } return error; } unsigned encode(std::vector& out, const std::vector& in, unsigned w, unsigned h, State& state) { if(lodepng_get_raw_size(w, h, &state.info_raw) > in.size()) return 84; return encode(out, in.empty() ? 0 : &in[0], w, h, state); } #ifdef LODEPNG_COMPILE_DISK unsigned encode(const std::string& filename, const unsigned char* in, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { std::vector buffer; unsigned error = encode(buffer, in, w, h, colortype, bitdepth); if(!error) error = save_file(buffer, filename); return error; } unsigned encode(const std::string& filename, const std::vector& in, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84; return encode(filename, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth); } #endif /* LODEPNG_COMPILE_DISK */ #endif /* LODEPNG_COMPILE_ENCODER */ #endif /* LODEPNG_COMPILE_PNG */ } /* namespace lodepng */ #endif /*LODEPNG_COMPILE_CPP*/ ================================================ FILE: src/lodepng/lodepng.h ================================================ /* LodePNG version 20260119 Copyright (c) 2005-2026 Lode Vandevenne This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution. */ #ifndef LODEPNG_H #define LODEPNG_H #include /*for size_t*/ extern const char* LODEPNG_VERSION_STRING; /* The following #defines are used to create code sections. They can be disabled to disable code sections, which can give faster compile time and smaller binary. The "NO_COMPILE" defines are designed to be used to pass as defines to the compiler command to disable them without modifying this header, e.g. -DLODEPNG_NO_COMPILE_ZLIB for gcc or clang. */ /*deflate & zlib. If disabled, you must specify alternative zlib functions in the custom_zlib field of the compress and decompress settings*/ #ifndef LODEPNG_NO_COMPILE_ZLIB /*pass -DLODEPNG_NO_COMPILE_ZLIB to the compiler to disable this, or comment out LODEPNG_COMPILE_ZLIB below*/ #define LODEPNG_COMPILE_ZLIB #endif /*png encoder and png decoder*/ #ifndef LODEPNG_NO_COMPILE_PNG /*pass -DLODEPNG_NO_COMPILE_PNG to the compiler to disable this, or comment out LODEPNG_COMPILE_PNG below*/ #define LODEPNG_COMPILE_PNG #endif /*deflate&zlib decoder and png decoder*/ #ifndef LODEPNG_NO_COMPILE_DECODER /*pass -DLODEPNG_NO_COMPILE_DECODER to the compiler to disable this, or comment out LODEPNG_COMPILE_DECODER below*/ #define LODEPNG_COMPILE_DECODER #endif /*deflate&zlib encoder and png encoder*/ #ifndef LODEPNG_NO_COMPILE_ENCODER /*pass -DLODEPNG_NO_COMPILE_ENCODER to the compiler to disable this, or comment out LODEPNG_COMPILE_ENCODER below*/ #define LODEPNG_COMPILE_ENCODER #endif /*the optional built in harddisk file loading and saving functions*/ #ifndef LODEPNG_NO_COMPILE_DISK /*pass -DLODEPNG_NO_COMPILE_DISK to the compiler to disable this, or comment out LODEPNG_COMPILE_DISK below*/ /*#define LODEPNG_COMPILE_DISK*/ /*disabled for pdvzip: we handle our own file I/O*/ #endif /*support for chunks other than IHDR, IDAT, PLTE, tRNS, IEND: ancillary and unknown chunks*/ #ifndef LODEPNG_NO_COMPILE_ANCILLARY_CHUNKS /*pass -DLODEPNG_NO_COMPILE_ANCILLARY_CHUNKS to the compiler to disable this, or comment out LODEPNG_COMPILE_ANCILLARY_CHUNKS below*/ /*#define LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /*disabled for pdvzip: iCCP chunk built manually, no other ancillary chunks needed*/ #endif /*ability to convert error numerical codes to English text string*/ #ifndef LODEPNG_NO_COMPILE_ERROR_TEXT /*pass -DLODEPNG_NO_COMPILE_ERROR_TEXT to the compiler to disable this, or comment out LODEPNG_COMPILE_ERROR_TEXT below*/ #define LODEPNG_COMPILE_ERROR_TEXT #endif /*Compile the default allocators (C's free, malloc and realloc). If you disable this, you can define the functions lodepng_free, lodepng_malloc and lodepng_realloc in your source files with custom allocators.*/ #ifndef LODEPNG_NO_COMPILE_ALLOCATORS /*pass -DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler to disable the built-in ones, or comment out LODEPNG_COMPILE_ALLOCATORS below*/ #define LODEPNG_COMPILE_ALLOCATORS #endif /*Disable built-in CRC function, in that case a custom implementation of lodepng_crc32 must be defined externally so that it can be linked in. The default built-in CRC code comes with 8KB of lookup tables, so for memory constrained environment you may want it disabled and provide a much smaller implementation externally as said above. You can find such an example implementation in a comment in the lodepng.c(pp) file in the 'else' case of the searchable LODEPNG_COMPILE_CRC section.*/ #ifndef LODEPNG_NO_COMPILE_CRC /*pass -DLODEPNG_NO_COMPILE_CRC to the compiler to disable the built-in one, or comment out LODEPNG_COMPILE_CRC below*/ #define LODEPNG_COMPILE_CRC #endif /*compile the C++ version (you can disable the C++ wrapper here even when compiling for C++)*/ #ifdef __cplusplus #ifndef LODEPNG_NO_COMPILE_CPP /*pass -DLODEPNG_NO_COMPILE_CPP to the compiler to disable C++ (not needed if a C-only compiler), or comment out LODEPNG_COMPILE_CPP below*/ #define LODEPNG_COMPILE_CPP #endif #endif #ifdef LODEPNG_COMPILE_CPP #include #include #endif /*LODEPNG_COMPILE_CPP*/ #ifdef LODEPNG_COMPILE_PNG /*The PNG color types (also used for raw image).*/ typedef enum LodePNGColorType { LCT_GREY = 0, /*grayscale: 1,2,4,8,16 bit*/ LCT_RGB = 2, /*RGB: 8,16 bit*/ LCT_PALETTE = 3, /*palette: 1,2,4,8 bit*/ LCT_GREY_ALPHA = 4, /*grayscale with alpha: 8,16 bit*/ LCT_RGBA = 6, /*RGB with alpha: 8,16 bit*/ /*LCT_MAX_OCTET_VALUE lets the compiler allow this enum to represent any invalid byte value from 0 to 255 that could be present in an invalid PNG file header. Do not use, compare with or set the name LCT_MAX_OCTET_VALUE, instead either use the valid color type names above, or numeric values like 1 or 7 when checking for particular disallowed color type byte values, or cast to integer to print it.*/ LCT_MAX_OCTET_VALUE = 255 } LodePNGColorType; #ifdef LODEPNG_COMPILE_DECODER /* Converts PNG data in memory to raw pixel data. out: Output parameter. Pointer to buffer that will contain the raw pixel data. After decoding, its size is w * h * (bytes per pixel) bytes larger than initially. Bytes per pixel depends on colortype and bitdepth. Must be freed after usage with free(*out). Note: for 16-bit per channel colors, uses big endian format like PNG does. w: Output parameter. Pointer to width of pixel data. h: Output parameter. Pointer to height of pixel data. in: Memory buffer with the PNG file. insize: size of the in buffer. colortype: the desired color type for the raw output image. See explanation on PNG color types. bitdepth: the desired bit depth for the raw output image. See explanation on PNG color types. Return value: LodePNG error code (0 means no error). */ unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize, LodePNGColorType colortype, unsigned bitdepth); /*Same as lodepng_decode_memory, but always decodes to 32-bit RGBA raw image*/ unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize); /*Same as lodepng_decode_memory, but always decodes to 24-bit RGB raw image*/ unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize); #ifdef LODEPNG_COMPILE_DISK /* Load PNG from disk, from file with given name. Same as the other decode functions, but instead takes a filename as input. NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and decode in-memory.*/ unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename, LodePNGColorType colortype, unsigned bitdepth); /*Same as lodepng_decode_file, but always decodes to 32-bit RGBA raw image. NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and decode in-memory.*/ unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename); /*Same as lodepng_decode_file, but always decodes to 24-bit RGB raw image. NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and decode in-memory.*/ unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename); #endif /*LODEPNG_COMPILE_DISK*/ #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER /* Converts raw pixel data into a PNG image in memory. The colortype and bitdepth of the output PNG image cannot be chosen, they are automatically determined by the colortype, bitdepth and content of the input pixel data. Note: for 16-bit per channel colors, needs big endian format like PNG does. out: Output parameter. Pointer to buffer that will contain the PNG image data. Must be freed after usage with free(*out). outsize: Output parameter. Pointer to the size in bytes of the out buffer. image: The raw pixel data to encode. The size of this buffer should be w * h * (bytes per pixel), bytes per pixel depends on colortype and bitdepth. w: width of the raw pixel data in pixels. h: height of the raw pixel data in pixels. colortype: the color type of the raw input image. See explanation on PNG color types. bitdepth: the bit depth of the raw input image. See explanation on PNG color types. Return value: LodePNG error code (0 means no error). */ unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth); /*Same as lodepng_encode_memory, but always encodes from 32-bit RGBA raw image.*/ unsigned lodepng_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h); /*Same as lodepng_encode_memory, but always encodes from 24-bit RGB raw image.*/ unsigned lodepng_encode24(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h); #ifdef LODEPNG_COMPILE_DISK /* Converts raw pixel data into a PNG file on disk. Same as the other encode functions, but instead takes a filename as output. NOTE: This overwrites existing files without warning! NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and encode in-memory.*/ unsigned lodepng_encode_file(const char* filename, const unsigned char* image, unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth); /*Same as lodepng_encode_file, but always encodes from 32-bit RGBA raw image. NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and encode in-memory.*/ unsigned lodepng_encode32_file(const char* filename, const unsigned char* image, unsigned w, unsigned h); /*Same as lodepng_encode_file, but always encodes from 24-bit RGB raw image. NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and encode in-memory.*/ unsigned lodepng_encode24_file(const char* filename, const unsigned char* image, unsigned w, unsigned h); #endif /*LODEPNG_COMPILE_DISK*/ #endif /*LODEPNG_COMPILE_ENCODER*/ #ifdef LODEPNG_COMPILE_CPP namespace lodepng { #ifdef LODEPNG_COMPILE_DECODER /*Same as lodepng_decode_memory, but decodes to an std::vector. The colortype is the format to output the pixels to. Default is RGBA 8-bit per channel.*/ unsigned decode(std::vector& out, unsigned& w, unsigned& h, const unsigned char* in, size_t insize, LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); unsigned decode(std::vector& out, unsigned& w, unsigned& h, const std::vector& in, LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); #ifdef LODEPNG_COMPILE_DISK /* Converts PNG file from disk to raw pixel data in memory. Same as the other decode functions, but instead takes a filename as input. NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and decode in-memory. */ unsigned decode(std::vector& out, unsigned& w, unsigned& h, const std::string& filename, LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); #endif /* LODEPNG_COMPILE_DISK */ #endif /* LODEPNG_COMPILE_DECODER */ #ifdef LODEPNG_COMPILE_ENCODER /*Same as lodepng_encode_memory, but encodes to an std::vector. colortype is that of the raw input data. The output PNG color type will be auto chosen.*/ unsigned encode(std::vector& out, const unsigned char* in, unsigned w, unsigned h, LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); unsigned encode(std::vector& out, const std::vector& in, unsigned w, unsigned h, LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); #ifdef LODEPNG_COMPILE_DISK /* Converts 32-bit RGBA raw pixel data into a PNG file on disk. Same as the other encode functions, but instead takes a filename as output. NOTE: This overwrites existing files without warning! NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and decode in-memory. */ unsigned encode(const std::string& filename, const unsigned char* in, unsigned w, unsigned h, LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); unsigned encode(const std::string& filename, const std::vector& in, unsigned w, unsigned h, LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); #endif /* LODEPNG_COMPILE_DISK */ #endif /* LODEPNG_COMPILE_ENCODER */ } /* namespace lodepng */ #endif /*LODEPNG_COMPILE_CPP*/ #endif /*LODEPNG_COMPILE_PNG*/ #ifdef LODEPNG_COMPILE_ERROR_TEXT /*Returns an English description of the numerical error code.*/ const char* lodepng_error_text(unsigned code); #endif /*LODEPNG_COMPILE_ERROR_TEXT*/ #ifdef LODEPNG_COMPILE_DECODER /*Settings for zlib decompression*/ typedef struct LodePNGDecompressSettings LodePNGDecompressSettings; struct LodePNGDecompressSettings { /* Check LodePNGDecoderSettings for more ignorable errors such as ignore_crc */ unsigned ignore_adler32; /*if 1, continue and don't give an error message if the Adler32 checksum is corrupted*/ unsigned ignore_nlen; /*ignore complement of len checksum in uncompressed blocks*/ /*Maximum decompressed size, beyond this the decoder may (and is encouraged to) stop decoding, return an error, output a data size > max_output_size and all the data up to that point. This is not hard limit nor a guarantee, but can prevent excessive memory usage. This setting is ignored by the PNG decoder, but is used by the deflate/zlib decoder and can be used by custom ones. Set to 0 to impose no limit (the default).*/ size_t max_output_size; /*use custom zlib decoder instead of built in one (default: null). Should return 0 if success, any non-0 if error (numeric value not exposed).*/ unsigned (*custom_zlib)(unsigned char**, size_t*, const unsigned char*, size_t, const LodePNGDecompressSettings*); /*use custom deflate decoder instead of built in one (default: null) if custom_zlib is not null, custom_inflate is ignored (the zlib format uses deflate). Should return 0 if success, any non-0 if error (numeric value not exposed).*/ unsigned (*custom_inflate)(unsigned char**, size_t*, const unsigned char*, size_t, const LodePNGDecompressSettings*); const void* custom_context; /*optional custom settings for custom functions*/ }; extern const LodePNGDecompressSettings lodepng_default_decompress_settings; void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings); #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER /* Settings for zlib compression. Tweaking these settings tweaks the balance between speed and compression ratio. */ typedef struct LodePNGCompressSettings LodePNGCompressSettings; struct LodePNGCompressSettings /*deflate = compress*/ { /*LZ77 related settings*/ unsigned btype; /*the block type for LZ (0, 1, 2 or 3, see zlib standard). Should be 2 for proper compression.*/ unsigned use_lz77; /*whether or not to use LZ77. Should be 1 for proper compression.*/ unsigned windowsize; /*must be a power of two <= 32768. higher compresses more but is slower. Default value: 2048.*/ unsigned minmatch; /*minimum lz77 length. 3 is normally best, 6 can be better for some PNGs. Default: 0*/ unsigned nicematch; /*stop searching if >= this length found. Set to 258 for best compression. Default: 128*/ unsigned lazymatching; /*use lazy matching: better compression but a bit slower. Default: true*/ /*use custom zlib encoder instead of built in one (default: null)*/ unsigned (*custom_zlib)(unsigned char**, size_t*, const unsigned char*, size_t, const LodePNGCompressSettings*); /*use custom deflate encoder instead of built in one (default: null) if custom_zlib is used, custom_deflate is ignored since only the built in zlib function will call custom_deflate*/ unsigned (*custom_deflate)(unsigned char**, size_t*, const unsigned char*, size_t, const LodePNGCompressSettings*); const void* custom_context; /*optional custom settings for custom functions*/ }; extern const LodePNGCompressSettings lodepng_default_compress_settings; void lodepng_compress_settings_init(LodePNGCompressSettings* settings); #endif /*LODEPNG_COMPILE_ENCODER*/ #ifdef LODEPNG_COMPILE_PNG /* Color mode of an image. Contains all information required to decode the pixel bits to RGBA colors. This information is the same as used in the PNG file format, and is used both for PNG and raw image data in LodePNG. */ typedef struct LodePNGColorMode { /*header (IHDR)*/ LodePNGColorType colortype; /*color type, see PNG standard or documentation further in this header file*/ unsigned bitdepth; /*bits per sample, see PNG standard or documentation further in this header file*/ /* palette (PLTE and tRNS) Dynamically allocated with the colors of the palette, including alpha. This field may not be allocated directly, use lodepng_color_mode_init first, then lodepng_palette_add per color to correctly initialize it (to ensure size of exactly 1024 bytes). The alpha channels must be set as well, set them to 255 for opaque images. When decoding, with the default settings you can ignore this palette, since LodePNG already fills the palette colors in the pixels of the raw RGBA output, but when decoding to the original PNG color mode it is needed to reconstruct the colors. The palette is only supported for color type 3. */ unsigned char* palette; /*palette in RGBARGBA... order. Must be either 0, or when allocated must have 1024 bytes*/ size_t palettesize; /*palette size in number of colors (amount of used bytes is 4 * palettesize)*/ /* transparent color key (tRNS) This color uses the same bit depth as the bitdepth value in this struct, which can be 1-bit to 16-bit. For grayscale PNGs, r, g and b will all 3 be set to the same. When decoding, by default you can ignore this information, since LodePNG sets pixels with this key to transparent already in the raw RGBA output. The color key is only supported for color types 0 and 2. */ unsigned key_defined; /*is a transparent color key given? 0 = false, 1 = true*/ unsigned key_r; /*red/grayscale component of color key*/ unsigned key_g; /*green component of color key*/ unsigned key_b; /*blue component of color key*/ } LodePNGColorMode; /*init, cleanup and copy functions to use with this struct*/ void lodepng_color_mode_init(LodePNGColorMode* info); void lodepng_color_mode_cleanup(LodePNGColorMode* info); /*return value is error code (0 means no error)*/ unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source); /* Makes a temporary LodePNGColorMode that does not need cleanup (no palette) */ LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth); void lodepng_palette_clear(LodePNGColorMode* info); /*add 1 color to the palette*/ unsigned lodepng_palette_add(LodePNGColorMode* info, unsigned char r, unsigned char g, unsigned char b, unsigned char a); /*get the total amount of bits per pixel, based on colortype and bitdepth in the struct*/ unsigned lodepng_get_bpp(const LodePNGColorMode* info); /*get the amount of color channels used, based on colortype in the struct. If a palette is used, it counts as 1 channel.*/ unsigned lodepng_get_channels(const LodePNGColorMode* info); /*is it a grayscale type? (only colortype 0 or 4)*/ unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info); /*has it got an alpha channel? (only colortype 2 or 6)*/ unsigned lodepng_is_alpha_type(const LodePNGColorMode* info); /*has it got a palette? (only colortype 3)*/ unsigned lodepng_is_palette_type(const LodePNGColorMode* info); /*only returns true if there is a palette and there is a value in the palette with alpha < 255. Loops through the palette to check this.*/ unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info); /* Check if the given color info indicates the possibility of having non-opaque pixels in the PNG image. Returns true if the image can have translucent or invisible pixels (it still be opaque if it doesn't use such pixels). Returns false if the image can only have opaque pixels. In detail, it returns true only if it's a color type with alpha, or has a palette with non-opaque values, or if "key_defined" is true. */ unsigned lodepng_can_have_alpha(const LodePNGColorMode* info); /*Returns the byte size of a raw image buffer with given width, height and color mode*/ size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*The information of a Time chunk in PNG.*/ typedef struct LodePNGTime { unsigned year; /*2 bytes used (0-65535)*/ unsigned month; /*1-12*/ unsigned day; /*1-31*/ unsigned hour; /*0-23*/ unsigned minute; /*0-59*/ unsigned second; /*0-60 (to allow for leap seconds)*/ } LodePNGTime; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /*Information about the PNG image, except pixels, width and height.*/ typedef struct LodePNGInfo { /*header (IHDR), palette (PLTE) and transparency (tRNS) chunks*/ unsigned compression_method;/*compression method of the original file. Always 0.*/ unsigned filter_method; /*filter method of the original file*/ unsigned interlace_method; /*interlace method of the original file: 0=none, 1=Adam7*/ LodePNGColorMode color; /*color type and bits, palette and transparency of the PNG file*/ #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /* Suggested background color chunk (bKGD) This uses the same color mode and bit depth as the PNG (except no alpha channel), with values truncated to the bit depth in the unsigned integer. For grayscale and palette PNGs, the value is stored in background_r. The values in background_g and background_b are then unused. The decoder will set them equal to background_r, the encoder ignores them in this case. When decoding, you may get these in a different color mode than the one you requested for the raw pixels: the colortype and bitdepth defined by info_png.color, that is the ones defined in the header of the PNG image, are used. When encoding with auto_convert, you must use the color model defined in info_png.color for these values. The encoder normally ignores info_png.color when auto_convert is on, but will use it to interpret these values (and convert copies of them to its chosen color model). When encoding, avoid setting this to an expensive color, such as a non-gray value when the image is gray, or the compression will be worse since it will be forced to write the PNG with a more expensive color mode (when auto_convert is on). The decoder does not use this background color to edit the color of pixels. This is a completely optional metadata feature. */ unsigned background_defined; /*is a suggested background color given?*/ unsigned background_r; /*red/gray/palette component of suggested background color*/ unsigned background_g; /*green component of suggested background color*/ unsigned background_b; /*blue component of suggested background color*/ /* Non-international text chunks (tEXt and zTXt) The char** arrays each contain num strings. The actual messages are in text_strings, while text_keys are keywords that give a short description what the actual text represents, e.g. Title, Author, Description, or anything else. All the string fields below including strings, keys, names and language tags are null terminated. The PNG specification uses null characters for the keys, names and tags, and forbids null characters to appear in the main text which is why we can use null termination everywhere here. A keyword is minimum 1 character and maximum 79 characters long (plus the additional null terminator). It's discouraged to use a single line length longer than 79 characters for texts. Don't allocate these text buffers yourself. Use the init/cleanup functions correctly and use lodepng_add_text and lodepng_clear_text. Standard text chunk keywords and strings are encoded using Latin-1. */ size_t text_num; /*the amount of texts in these char** buffers (there may be more texts in itext)*/ char** text_keys; /*the keyword of a text chunk (e.g. "Comment")*/ char** text_strings; /*the actual text*/ /* International text chunks (iTXt) Similar to the non-international text chunks, but with additional strings "langtags" and "transkeys", and the following text encodings are used: keys: Latin-1, langtags: ASCII, transkeys and strings: UTF-8. keys must be 1-79 characters (plus the additional null terminator), the other strings are any length. */ size_t itext_num; /*the amount of international texts in this PNG*/ char** itext_keys; /*the English keyword of the text chunk (e.g. "Comment")*/ char** itext_langtags; /*language tag for this text's language, ISO/IEC 646 string, e.g. ISO 639 language tag*/ char** itext_transkeys; /*keyword translated to the international language - UTF-8 string*/ char** itext_strings; /*the actual international text - UTF-8 string*/ /* Optional exif metadata in exif_size bytes. Don't allocate this buffer yourself. Use the init/cleanup functions correctly and use lodepng_set_exif and lodepng_clear_exif. The exif data is in exif-encoded form but without JPEG markers, starting with the 'II' or 'MM' marker that indicates endianness. It's up to an exif handling library to encode/decode its information. */ unsigned exif_defined; /* Whether exif metadata is present, that is, the PNG image has an eXIf chunk */ unsigned char* exif; /* The bytes of the exif metadata, if present */ unsigned exif_size; /* The size of the exif data in bytes */ /*time chunk (tIME)*/ unsigned time_defined; /*set to 1 to make the encoder generate a tIME chunk*/ LodePNGTime time; /*phys chunk (pHYs)*/ unsigned phys_defined; /*if 0, there is no pHYs chunk and the values below are undefined, if 1 else there is one*/ unsigned phys_x; /*pixels per unit in x direction*/ unsigned phys_y; /*pixels per unit in y direction*/ unsigned phys_unit; /*may be 0 (unknown unit) or 1 (metre)*/ /* Color profile related chunk types: cICP, iCPP, sRGB, gAMA, cHRM, sBIT LodePNG does not apply any color conversions on pixels in the encoder or decoder and does not interpret these color profile values. It merely passes on the information. If you wish to use color profiles and convert colors, a separate color management library should be used. There is also a limited library for this in lodepng_util.h. There are 4 types of (sets of) chunks providing color information. If multiple are present, each will be decoded by LodePNG, but only one should be handled by the user, with the following order of priority depending on what the user supports: 1: cICP: Coding-independent code points (CICP) 2: iCCP: ICC profile 3: sRGB: indicates the image is in the sRGB color profile 4: gAMA and cHRM: indicates a gamma and chromaticity value to define the color profile */ /* gAMA chunk: Image gamma Optional, overridden by cICP, iCCP or sRGB if those are present. Together with cHRM, this is a primitive way of specifying the image color profile. */ unsigned gama_defined; /* Whether a gAMA chunk is present (0 = not present, 1 = present). */ unsigned gama_gamma; /* Gamma exponent times 100000 */ /* cHRM chunk: Primary chromaticities and white point Optional, overridden by cICP, iCCP or sRGB if those are present. Together with gAMA, this is a primitive way of specifying the image color profile. */ unsigned chrm_defined; /* Whether a cHRM chunk is present (0 = not present, 1 = present). */ unsigned chrm_white_x; /* White Point x times 100000 */ unsigned chrm_white_y; /* White Point y times 100000 */ unsigned chrm_red_x; /* Red x times 100000 */ unsigned chrm_red_y; /* Red y times 100000 */ unsigned chrm_green_x; /* Green x times 100000 */ unsigned chrm_green_y; /* Green y times 100000 */ unsigned chrm_blue_x; /* Blue x times 100000 */ unsigned chrm_blue_y; /* Blue y times 100000 */ /* sRGB chunk: Indicates the image is in the sRGB color space. Optional. Should not appear at the same time as iCCP. If gAMA is also present gAMA must contain value 45455. If cHRM is also present cHRM must contain respectively 31270,32900,64000,33000,30000,60000,15000,6000. */ unsigned srgb_defined; /* Whether an sRGB chunk is present (0 = not present, 1 = present). */ unsigned srgb_intent; /* Rendering intent: 0=perceptual, 1=rel. colorimetric, 2=saturation, 3=abs. colorimetric */ /* iCCP chunk: Embedded ICC profile. Optional. Should not appear at the same time as sRGB. Contains ICC profile, which can use any version of the ICC.1 specification by the International Color Consortium. See its specification for more details. LodePNG does not parse or use the ICC profile (except its color space header field for "RGB" or "GRAY", see below), a separate library to handle the ICC data format is needed to use it for color management and conversions. For encoding, if iCCP is present, the PNG specification recommends to also add gAMA and cHRM chunks that approximate the ICC profile, for compatibility with applications that don't use the ICC chunk. This is not required, and it's up to the user to compute approximate values and set then in the appropriate gama_ and chrm_ fields, LodePNG does not do this automatically since it does not interpret the ICC profile. For encoding, the ICC profile is required by the PNG specification to be an "RGB" profile for non-gray PNG color types (types 2, 3 and 6) and a "GRAY" profile for gray PNG color types (types 1 and 4). If you disable auto_convert, you must ensure the ICC profile type matches your requested color type, else the encoder gives an error. If auto_convert is enabled (the default), and the ICC profile is not a correct match for the pixel data, this will result in an encoder error if the pixel data has non-gray pixels for a GRAY profile, or a silent less-optimal compression of the pixel data if the pixels could be encoded as grayscale but the ICC profile is RGB. To avoid this do not set an ICC profile in the image unless there is a good reason for it, and when doing so make sure you compute it carefully to avoid the above problems. */ unsigned iccp_defined; /* Whether an iCCP chunk is present (0 = not present, 1 = present). */ char* iccp_name; /* Null terminated string with profile name, 1-79 bytes */ /* The ICC profile in iccp_profile_size bytes. Don't allocate this buffer yourself. Use the init/cleanup functions correctly and use lodepng_set_icc and lodepng_clear_icc. */ unsigned char* iccp_profile; unsigned iccp_profile_size; /* The size of iccp_profile in bytes */ /* cICP chunk: Coding-independent code points for video signal type identification. Optional. If present, and supported, overrides iCCP, sRGB, gAMA and cHRM. The meaning of the values are as defined in the specification ITU-T-H.273. LodePNG does not use these values, only passes on the metadata. The meaning of the values is they are enum values representing certain color spaces, including HDR color spaces, such as Display P3, PQ and HLG. The video full range flag value should typically be 1 for the use cases of PNG images, but can be 0 for narrow-range images in certain video editing workflows. */ unsigned cicp_defined; /* Whether an cICP chunk is present (0 = not present, 1 = present). */ unsigned cicp_color_primaries; /* Colour primaries value */ unsigned cicp_transfer_function; /* Transfer characteristics value */ unsigned cicp_matrix_coefficients; /* Matrix coefficients value */ unsigned cicp_video_full_range_flag; /* Video full range flag value */ /* mDCV chunk: Mastering Display Color Volume. Optional, typically used in conjunction with certain HDR color spaces that can be represented by the cICP chunk. See the PNG specification, third edition, for more information on this chunk. All the red, green, blue and white x and y values are encoded as 16-bit integers and therefore must be in range 0-65536. The min and max luminance values are 32-bit integers. */ unsigned mdcv_defined; /* Whether an mDCV chunk is present (0 = not present, 1 = present). */ /* Mastering display color primary chromaticities (CIE 1931 x,y of R,G,B) */ unsigned mdcv_red_x; /* Red x times 50000 */ unsigned mdcv_red_y; /* Red y times 50000 */ unsigned mdcv_green_x; /* Green x times 50000 */ unsigned mdcv_green_y; /* Green y times 50000 */ unsigned mdcv_blue_x; /* Blue x times 50000 */ unsigned mdcv_blue_y; /* Blue y times 50000 */ /* Mastering display white point chromaticity (CIE 1931 x,y) */ unsigned mdcv_white_x; /* White Point x times 50000 */ unsigned mdcv_white_y; /* White Point y times 50000 */ /* Mastering display luminance */ unsigned mdcv_max_luminance; /* Max luminance in cd/m^2 times 10000 */ unsigned mdcv_min_luminance; /* Min luminance in cd/m^2 times 10000 */ /* cLLI chunk: Content Light Level Information. Optional, typically used in conjunction with certain HDR color spaces that can be represented by the cICP chunk. See the PNG specification, third edition, for more information on this chunk. The clli_max_cll and clli_max_fall values are 32-bit integers. */ unsigned clli_defined; /* Whether a cLLI chunk is present (0 = not present, 1 = present). */ unsigned clli_max_cll; /* Maximum Content Light Level (MaxCLL) in cd/m^2 times 10000 */ unsigned clli_max_fall; /* Maximum Frame-Average Light Level (MaxFALL) in cd/m^2 times 10000 */ /* sBIT chunk: significant bits. Optional metadata, only set this if needed. If defined, these values give the bit depth of the original data. Since PNG only stores 1, 2, 4, 8 or 16-bit per channel data, the significant bits value can be used to indicate the original encoded data has another sample depth, such as 10 or 12. Encoders using this value, when storing the pixel data, should use the most significant bits of the data to store the original bits, and use a good sample depth scaling method such as "left bit replication" to fill in the least significant bits, rather than fill zeroes. Decoders using this value, if able to work with data that's e.g. 10-bit or 12-bit, should right shift the data to go back to the original bit depth, but decoders are also allowed to ignore sbit and work e.g. with the 8-bit or 16-bit data from the PNG directly, since thanks to the encoder contract, the values encoded in PNG are in valid range for the PNG bit depth. For grayscale images, sbit_g and sbit_b are not used, and for images that don't use color type RGBA or grayscale+alpha, sbit_a is not used (it's not used even for palette images with translucent palette values, or images with color key). The values that are used must be greater than zero and smaller than or equal to the PNG bit depth. The color type from the header in the PNG image defines these used and unused fields: if decoding with a color mode conversion, such as always decoding to RGBA, this metadata still only uses the color type of the original PNG, and may e.g. lack the alpha channel info if the PNG was RGB. When encoding with auto_convert (as well as without), also always the color model defined in info_png.color determines this. NOTE: enabling sbit can hurt compression, because the encoder can then not always use auto_convert to choose a more optimal color mode for the data, because the PNG format has strict requirements for the allowed sbit values in combination with color modes. For example, setting these fields to 10-bit will force the encoder to keep using a 16-bit per channel color mode, even if the pixel data would in fact fit in a more efficient 8-bit mode. */ unsigned sbit_defined; /*is significant bits given? if not, the values below are unused*/ unsigned sbit_r; /*red or gray component of significant bits*/ unsigned sbit_g; /*green component of significant bits*/ unsigned sbit_b; /*blue component of significant bits*/ unsigned sbit_a; /*alpha component of significant bits*/ /* End of color profile related chunks */ /* unknown chunks: chunks not known by LodePNG, passed on byte for byte. There are 3 buffers, one for each position in the PNG where unknown chunks can appear. Each buffer contains all unknown chunks for that position consecutively. The 3 positions are: 0: between IHDR and PLTE, 1: between PLTE and IDAT, 2: between IDAT and IEND. For encoding, do not store critical chunks or known chunks that are enabled with a "_defined" flag above in here, since the encoder will blindly follow this and could then encode an invalid PNG file (such as one with two IHDR chunks or the disallowed combination of sRGB with iCCP). But do use this if you wish to store an ancillary chunk that is not supported by LodePNG (such as sPLT or hIST), or any non-standard PNG chunk. Do not allocate or traverse this data yourself. Use the chunk traversing functions declared later, such as lodepng_chunk_next and lodepng_chunk_append, to read/write this struct. */ unsigned char* unknown_chunks_data[3]; size_t unknown_chunks_size[3]; /*size in bytes of the unknown chunks, given for protection*/ #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } LodePNGInfo; /*init, cleanup and copy functions to use with this struct*/ void lodepng_info_init(LodePNGInfo* info); /*destructs the LodePNGInfo and brings it to invalid state, requiring lodepng_info_init again before reusing it*/ void lodepng_info_cleanup(LodePNGInfo* info); /*return value is error code (0 means no error)*/ unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source); #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str); /*push back both texts at once*/ void lodepng_clear_text(LodePNGInfo* info); /*use this to clear the texts again after you filled them in*/ unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag, const char* transkey, const char* str); /*push back the 4 texts of 1 chunk at once*/ void lodepng_clear_itext(LodePNGInfo* info); /*use this to clear the itexts again after you filled them in*/ /*replaces if exists*/ unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size); void lodepng_clear_icc(LodePNGInfo* info); /*use this to clear the profile again after you filled it in*/ /*replaces if exists*/ unsigned lodepng_set_exif(LodePNGInfo* info, const unsigned char* exif, unsigned exif_size); void lodepng_clear_exif(LodePNGInfo* info); /*use this to clear the exif metadata again after you filled it in*/ #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ /* Converts raw buffer from one color type to another color type, based on LodePNGColorMode structs to describe the input and output color type. See the reference manual at the end of this header file to see which color conversions are supported. return value = LodePNG error code (0 if all went ok, an error if the conversion isn't supported) The out buffer must have size (w * h * bpp + 7) / 8, where bpp is the bits per pixel of the output color type (lodepng_get_bpp). For < 8 bpp images, there should not be padding bits at the end of scanlines. For 16-bit per channel colors, uses big endian format like PNG does. Return value is LodePNG error code */ unsigned lodepng_convert(unsigned char* out, const unsigned char* in, const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, unsigned w, unsigned h); #ifdef LODEPNG_COMPILE_DECODER /* Settings for the decoder. This contains settings for the PNG and the Zlib decoder, but not the Info settings from the Info structs. */ typedef struct LodePNGDecoderSettings { LodePNGDecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/ /* Check LodePNGDecompressSettings for more ignorable errors such as ignore_adler32 */ unsigned ignore_crc; /*ignore CRC checksums*/ unsigned ignore_critical; /*ignore unknown critical chunks*/ unsigned ignore_end; /*ignore issues at end of file if possible (missing IEND chunk, too large chunk, ...)*/ /* TODO: make a system involving warnings with levels and a strict mode instead. Other potentially recoverable errors: srgb rendering intent value, size of content of ancillary chunks, more than 79 characters for some strings, placement/combination rules for ancillary chunks, crc of unknown chunks, allowed characters in string keys, invalid characters in chunk types names, etc... */ unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/ #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS unsigned read_text_chunks; /*if false but remember_unknown_chunks is true, they're stored in the unknown chunks*/ /*store all bytes from unknown chunks in the LodePNGInfo (off by default, useful for a png editor)*/ unsigned remember_unknown_chunks; /* maximum size for decompressed text chunks. If a text chunk's text is larger than this, an error is returned, unless reading text chunks is disabled or this limit is set higher or disabled. Set to 0 to allow any size. By default it is a value that prevents unreasonably large strings from hogging memory. */ size_t max_text_size; /* maximum size for compressed ICC chunks. If the ICC profile is larger than this, an error will be returned. Set to 0 to allow any size. By default this is a value that prevents ICC profiles that would be much larger than any legitimate profile could be to hog memory. */ size_t max_icc_size; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } LodePNGDecoderSettings; void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings); #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER /*strategy to use to choose the PNG filter per scanline. Strategies 0-4 correspond to each of the 5 filter types PNG supports, the next values are adaptive strategies*/ typedef enum LodePNGFilterStrategy { /*every filter at zero*/ LFS_ZERO = 0, /*every filter at 1, 2, 3 or 4 (paeth), unlike LFS_ZERO not a good choice, but for testing*/ LFS_ONE = 1, LFS_TWO = 2, LFS_THREE = 3, LFS_FOUR = 4, /*Use the filter out of the 5 above types that gives minimum sum, by trying each one. This is the adaptive filtering suggested heuristic in the PNG standard chapter 'Filter selection'.*/ LFS_MINSUM, /*Use the filter type that gives smallest Shannon entropy for this scanline. Depending on the image, this is better or worse than minsum.*/ LFS_ENTROPY, /* Brute-force-search PNG filters by compressing each filter for each scanline. Experimental, very slow, and only rarely gives better compression than MINSUM. */ LFS_BRUTE_FORCE, /*use predefined_filters buffer: you specify the filter type for each scanline*/ LFS_PREDEFINED } LodePNGFilterStrategy; /*Gives characteristics about the integer RGBA colors of the image (count, alpha channel usage, bit depth, ...), which helps decide which color model to use for encoding. Used internally by default if "auto_convert" is enabled. Public because it's useful for custom algorithms.*/ typedef struct LodePNGColorStats { unsigned colored; /*not grayscale*/ unsigned key; /*image is not opaque and color key is possible instead of full alpha*/ unsigned short key_r; /*key values, always as 16-bit, in 8-bit case the byte is duplicated, e.g. 65535 means 255*/ unsigned short key_g; unsigned short key_b; unsigned alpha; /*image is not opaque and alpha channel or alpha palette required*/ unsigned numcolors; /*amount of colors, up to 257. Not valid if bits == 16 or allow_palette is disabled.*/ unsigned char palette[1024]; /*Remembers up to the first 256 RGBA colors, in no particular order, only valid when numcolors is valid*/ unsigned bits; /*bits per channel (not for palette). 1,2 or 4 for grayscale only. 16 if 16-bit per channel required.*/ size_t numpixels; /*user settings for computing/using the stats*/ unsigned allow_palette; /*default 1. if 0, disallow choosing palette colortype in auto_choose_color, and don't count numcolors*/ unsigned allow_greyscale; /*default 1. if 0, choose RGB or RGBA even if the image only has gray colors*/ } LodePNGColorStats; void lodepng_color_stats_init(LodePNGColorStats* stats); /*Get a LodePNGColorStats of the image. The stats must already have been inited. Returns error code (e.g. alloc fail) or 0 if ok.*/ unsigned lodepng_compute_color_stats(LodePNGColorStats* stats, const unsigned char* image, unsigned w, unsigned h, const LodePNGColorMode* mode_in); /*Settings for the encoder.*/ typedef struct LodePNGEncoderSettings { LodePNGCompressSettings zlibsettings; /*settings for the zlib encoder, such as window size, ...*/ /*automatically choose output PNG color type. If false, must explicitly choose the output color type in state.info_png.color.colortype, info_png.color.bitdepth and optionally its palette. Default: true*/ unsigned auto_convert; /*If true, follows the suggestion in the PNG standard in chapter 'Filter selection': if the PNG uses a palette or lower than 8 bit depth, set all filters to zero. In other cases this will use the heuristic from the chosen filter_strategy. The PNG standard suggests LFS_MINSUM for those cases.*/ unsigned filter_palette_zero; /*Which filter strategy to use when not using zeroes due to filter_palette_zero. Set filter_palette_zero to 0 to ensure always using your chosen strategy. Default: LFS_MINSUM*/ LodePNGFilterStrategy filter_strategy; /*used if filter_strategy is LFS_PREDEFINED. In that case, this must point to a buffer with the same length as the amount of scanlines in the image, and each value must <= 5. You have to cleanup this buffer, LodePNG will never free it. Don't forget that filter_palette_zero must be set to 0 to ensure this is also used on palette or low bitdepth images.*/ const unsigned char* predefined_filters; /*force creating a PLTE chunk if colortype is 2 or 6 (= a suggested palette). If colortype is 3, PLTE is always created. If color type is explicitly set to a grayscale type (1 or 4), this is not done and is ignored. If enabling this, a palette must be present in the info_png. NOTE: enabling this may worsen compression if auto_convert is used to choose optimal color mode, because it cannot use grayscale color modes in this case*/ unsigned force_palette; #ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS /*add LodePNG identifier and version as a text chunk, for debugging*/ unsigned add_id; /*encode text chunks as zTXt chunks instead of tEXt chunks, and use compression in iTXt chunks*/ unsigned text_compression; #endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ } LodePNGEncoderSettings; void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings); #endif /*LODEPNG_COMPILE_ENCODER*/ #if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) /*The settings, state and information for extended encoding and decoding. Using this struct requires using lodepng_state_init to initialize it and using lodepng_state_cleanup to deconstruct it. If using C++, you can use lodepng::State instead which does those things automatically with RAII. While a LodePNGState can be reused once in a chain of lodepng_decode followed by lodepng_encode, it's not recommended to reuse it for multiple encode, decode or inspect calls, and if any such function returns an error code, the LodePNGState should not be reused at all as it can be in an unexpected state.. */ typedef struct LodePNGState { #ifdef LODEPNG_COMPILE_DECODER LodePNGDecoderSettings decoder; /*the decoding settings*/ #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER LodePNGEncoderSettings encoder; /*the encoding settings*/ #endif /*LODEPNG_COMPILE_ENCODER*/ LodePNGColorMode info_raw; /*specifies the format in which you would like to get the raw pixel buffer*/ LodePNGInfo info_png; /*info of the PNG image obtained after decoding*/ unsigned error; /*deprecated, use the return value of the encode/decode functions to check errors instead*/ } LodePNGState; /*init, cleanup and copy functions to use with this struct*/ void lodepng_state_init(LodePNGState* state); /*destructs the LodePNGState and brings it to invalid state, requiring lodepng_info_init again before reusing it*/ void lodepng_state_cleanup(LodePNGState* state); /*return value is error code (0 means no error)*/ unsigned lodepng_state_copy(LodePNGState* dest, const LodePNGState* source); #endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */ #ifdef LODEPNG_COMPILE_DECODER /* Same as lodepng_decode_memory, but uses a LodePNGState to allow custom settings and getting much more information about the PNG image and color mode. */ unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize); /* Read the PNG header, but not the actual data. This returns only the information that is in the IHDR chunk of the PNG, such as width, height and color type. The information is placed in the info_png field of the LodePNGState. */ unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize); #endif /*LODEPNG_COMPILE_DECODER*/ /* Reads one metadata chunk (other than IHDR, which is handled by lodepng_inspect) of the PNG file and outputs what it read in the state. Returns error code on failure. Use lodepng_inspect first with a new state, then e.g. lodepng_chunk_find_const to find the desired chunk type, and if non null use lodepng_inspect_chunk (with chunk_pointer - start_of_file as pos). Supports most metadata chunks from the PNG standard (gAMA, bKGD, tEXt, ...). Ignores unsupported, unknown, non-metadata or IHDR chunks (without error). Requirements: &in[pos] must point to start of a chunk, must use regular lodepng_inspect first since format of most other chunks depends on IHDR, and if there is a PLTE chunk, that one must be inspected before tRNS or bKGD. */ unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos, const unsigned char* in, size_t insize); #ifdef LODEPNG_COMPILE_ENCODER /*This function allocates the out buffer with standard malloc and stores the size in *outsize.*/ unsigned lodepng_encode(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h, LodePNGState* state); #endif /*LODEPNG_COMPILE_ENCODER*/ /* The lodepng_chunk functions are normally not needed, except to traverse the unknown chunks stored in the LodePNGInfo struct, or add new ones to it. It also allows traversing the chunks of an encoded PNG file yourself. The chunk pointer always points to the beginning of the chunk itself, that is the first byte of the 4 length bytes. In the PNG file format, chunks have the following format: -4 bytes length: length of the data of the chunk in bytes (chunk itself is 12 bytes longer) -4 bytes chunk type (ASCII a-z,A-Z only, see below) -length bytes of data (may be 0 bytes if length was 0) -4 bytes of CRC, computed on chunk name + data The first chunk starts at the 8th byte of the PNG file, the entire rest of the file exists out of concatenated chunks with the above format. PNG standard chunk ASCII naming conventions: -First byte: uppercase = critical, lowercase = ancillary -Second byte: uppercase = public, lowercase = private -Third byte: must be uppercase -Fourth byte: uppercase = unsafe to copy, lowercase = safe to copy */ /* Gets the length of the data of the chunk. Total chunk length has 12 bytes more. There must be at least 4 bytes to read from. If the result value is too large, it may be corrupt data. */ unsigned lodepng_chunk_length(const unsigned char* chunk); /*puts the 4-byte type in null terminated string*/ void lodepng_chunk_type(char type[5], const unsigned char* chunk); /*check if the type is the given type*/ unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type); /*0: it's one of the critical chunk types, 1: it's an ancillary chunk (see PNG standard)*/ unsigned char lodepng_chunk_ancillary(const unsigned char* chunk); /*0: public, 1: private (see PNG standard)*/ unsigned char lodepng_chunk_private(const unsigned char* chunk); /*0: the chunk is unsafe to copy, 1: the chunk is safe to copy (see PNG standard)*/ unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk); /*get pointer to the data of the chunk, where the input points to the header of the chunk*/ unsigned char* lodepng_chunk_data(unsigned char* chunk); const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk); /*returns 0 if the crc is correct, 1 if it's incorrect (0 for OK as usual!)*/ unsigned lodepng_chunk_check_crc(const unsigned char* chunk); /*generates the correct CRC from the data and puts it in the last 4 bytes of the chunk*/ void lodepng_chunk_generate_crc(unsigned char* chunk); /* Iterate to next chunks, allows iterating through all chunks of the PNG file. Input must be at the beginning of a chunk (result of a previous lodepng_chunk_next call, or the 8th byte of a PNG file which always has the first chunk), or alternatively may point to the first byte of the PNG file (which is not a chunk but the magic header, the function will then skip over it and return the first real chunk). Will output pointer to the start of the next chunk, or at or beyond end of the file if there is no more chunk after this or possibly if the chunk is corrupt. Start this process at the 8th byte of the PNG file. In a non-corrupt PNG file, the last chunk should have name "IEND". */ unsigned char* lodepng_chunk_next(unsigned char* chunk, unsigned char* end); const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end); /*Finds the first chunk with the given type in the range [chunk, end), or returns NULL if not found.*/ unsigned char* lodepng_chunk_find(unsigned char* chunk, unsigned char* end, const char type[5]); const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]); /* Appends chunk to the data in out. The given chunk should already have its chunk header. The out variable and outsize are updated to reflect the new reallocated buffer. Returns error code (0 if it went ok) */ unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk); /* Appends new chunk to out. The chunk to append is given by giving its length, type and data separately. The type is a 4-letter string. The out variable and outsize are updated to reflect the new reallocated buffer. Returns error code (0 if it went ok) */ unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, size_t length, const char* type, const unsigned char* data); /*Calculate CRC32 of buffer*/ unsigned lodepng_crc32(const unsigned char* buf, size_t len); #endif /*LODEPNG_COMPILE_PNG*/ #ifdef LODEPNG_COMPILE_ZLIB /* This zlib part can be used independently to zlib compress and decompress a buffer. It cannot be used to create gzip files however, and it only supports the part of zlib that is required for PNG, it does not support dictionaries. */ #ifdef LODEPNG_COMPILE_DECODER /*Inflate a buffer. Inflate is the decompression step of deflate. Out buffer must be freed after use.*/ unsigned lodepng_inflate(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings); /* Decompresses Zlib data. Reallocates the out buffer and appends the data. The data must be according to the zlib specification. Either, *out must be NULL and *outsize must be 0, or, *out must be a valid buffer and *outsize its size in bytes. out must be freed by user after usage. */ unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings); #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER /* Compresses data with Zlib. Reallocates the out buffer and appends the data. Zlib adds a small header and trailer around the deflate data. The data is output in the format of the zlib specification. Either, *out must be NULL and *outsize must be 0, or, *out must be a valid buffer and *outsize its size in bytes. out must be freed by user after usage. */ unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings); /* Find length-limited Huffman code for given frequencies. This function is in the public interface only for tests, it's used internally by lodepng_deflate. */ unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies, size_t numcodes, unsigned maxbitlen); /*Compress a buffer with deflate. See RFC 1951. Out buffer must be freed after use.*/ unsigned lodepng_deflate(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodePNGCompressSettings* settings); #endif /*LODEPNG_COMPILE_ENCODER*/ #endif /*LODEPNG_COMPILE_ZLIB*/ #ifdef LODEPNG_COMPILE_DISK /* Load a file from disk into buffer. The function allocates the out buffer, and after usage you should free it. out: output parameter, contains pointer to loaded buffer. outsize: output parameter, size of the allocated out buffer filename: the path to the file to load return value: error code (0 means ok) NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and decode in-memory. */ unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename); /* Save a file from buffer to disk. Warning, if it exists, this function overwrites the file without warning! buffer: the buffer to write buffersize: size of the buffer to write filename: the path to the file to save to return value: error code (0 means ok) NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and encode in-memory */ unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename); #endif /*LODEPNG_COMPILE_DISK*/ #ifdef LODEPNG_COMPILE_CPP /* The LodePNG C++ wrapper uses std::vectors instead of manually allocated memory buffers. */ namespace lodepng { #ifdef LODEPNG_COMPILE_PNG /* Wrapper around LodePNGState, which automatically calls lodepng_state_init in the constructor and lodepng_state_cleanup in the desctructor.*/ class State : public LodePNGState { public: State(); State(const State& other); ~State(); State& operator=(const State& other); }; #ifdef LODEPNG_COMPILE_DECODER /* Same as other lodepng::decode, but using a State for more settings and information. */ unsigned decode(std::vector& out, unsigned& w, unsigned& h, State& state, const unsigned char* in, size_t insize); unsigned decode(std::vector& out, unsigned& w, unsigned& h, State& state, const std::vector& in); #endif /*LODEPNG_COMPILE_DECODER*/ #ifdef LODEPNG_COMPILE_ENCODER /* Same as other lodepng::encode, but using a State for more settings and information. */ unsigned encode(std::vector& out, const unsigned char* in, unsigned w, unsigned h, State& state); unsigned encode(std::vector& out, const std::vector& in, unsigned w, unsigned h, State& state); #endif /*LODEPNG_COMPILE_ENCODER*/ #ifdef LODEPNG_COMPILE_DISK /* Load a file from disk into an std::vector. return value: error code (0 means ok) NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and decode in-memory */ unsigned load_file(std::vector& buffer, const std::string& filename); /* Save the binary data in an std::vector to a file on disk. The file is overwritten without warning. NOTE: Wide-character filenames are not supported, you can use an external method to handle such files and encode in-memory */ unsigned save_file(const std::vector& buffer, const std::string& filename); #endif /* LODEPNG_COMPILE_DISK */ #endif /* LODEPNG_COMPILE_PNG */ #ifdef LODEPNG_COMPILE_ZLIB #ifdef LODEPNG_COMPILE_DECODER /* Zlib-decompress an unsigned char buffer */ unsigned decompress(std::vector& out, const unsigned char* in, size_t insize, const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings); /* Zlib-decompress an std::vector */ unsigned decompress(std::vector& out, const std::vector& in, const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings); #endif /* LODEPNG_COMPILE_DECODER */ #ifdef LODEPNG_COMPILE_ENCODER /* Zlib-compress an unsigned char buffer */ unsigned compress(std::vector& out, const unsigned char* in, size_t insize, const LodePNGCompressSettings& settings = lodepng_default_compress_settings); /* Zlib-compress an std::vector */ unsigned compress(std::vector& out, const std::vector& in, const LodePNGCompressSettings& settings = lodepng_default_compress_settings); #endif /* LODEPNG_COMPILE_ENCODER */ #endif /* LODEPNG_COMPILE_ZLIB */ } /* namespace lodepng */ #endif /*LODEPNG_COMPILE_CPP*/ /* TODO: [.] test if there are no memory leaks or security exploits - done a lot but needs to be checked often [.] check compatibility with various compilers - done but needs to be redone for every newer version [X] converting color to 16-bit per channel types [X] support color profile chunk types (but never let them touch RGB values by default) [ ] support all second edition public PNG chunk types (almost done except sPLT and hIST) [X] support non-animation third edition public PNG chunk types: eXIf, cICP, mDCV, cLLI [ ] make sure encoder generates no chunks with size > (2^31)-1 [ ] partial decoding (stream processing) [X] let the "isFullyOpaque" function check color keys and transparent palettes too [X] better name for the variables "codes", "codesD", "codelengthcodes", "clcl" and "lldl" [ ] allow treating some errors like warnings, when image is recoverable (e.g. 69, 57, 58) [ ] make warnings like: oob palette, checksum fail, data after iend, wrong/unknown crit chunk, no null terminator in text, ... [ ] error messages with line numbers (and version) [ ] errors in state instead of as return code? [ ] new errors/warnings like suspiciously big decompressed ztxt or iccp chunk [ ] let the C++ wrapper catch exceptions coming from the standard library and return LodePNG error codes [ ] allow user to provide custom color conversion functions, e.g. for premultiplied alpha, padding bits or not, ... [ ] allow user to give data (void*) to custom allocator [X] provide alternatives for C library functions not present on some platforms (memcpy, ...) */ #endif /*LODEPNG_H inclusion guard*/ /* LodePNG Documentation --------------------- 0. table of contents -------------------- 1. about 1.1. supported features 1.2. features not supported 2. C and C++ version 3. security 4. decoding 5. encoding 6. color conversions 6.1. PNG color types 6.2. color conversions 6.3. padding bits 6.4. A note about 16-bits per channel and endianness 7. error values 8. chunks and PNG editing 9. compiler support 10. examples 10.1. decoder C++ example 10.2. decoder C example 11. state settings reference 12. changes 13. contact information 1. about -------- PNG is a file format to store raster images losslessly with good compression, supporting different color types and alpha channel. LodePNG is a PNG codec according to the Portable Network Graphics (PNG) Specification (Second Edition) - W3C Recommendation 10 November 2003. The specifications used are: *) Portable Network Graphics (PNG) Specification (Second Edition): http://www.w3.org/TR/2003/REC-PNG-20031110 *) RFC 1950 ZLIB Compressed Data Format version 3.3: http://www.gzip.org/zlib/rfc-zlib.html *) RFC 1951 DEFLATE Compressed Data Format Specification ver 1.3: http://www.gzip.org/zlib/rfc-deflate.html The most recent version of LodePNG can currently be found at http://lodev.org/lodepng/ LodePNG works both in C (ISO C90) and C++, with a C++ wrapper that adds extra functionality. LodePNG exists out of two files: -lodepng.h: the header file for both C and C++ -lodepng.c(pp): give it the name lodepng.c or lodepng.cpp (or .cc) depending on your usage If you want to start using LodePNG right away without reading this doc, get the examples from the LodePNG website to see how to use it in code, or check the smaller examples in chapter 13 here. LodePNG is simple but only supports the basic requirements. To achieve simplicity, the following design choices were made: There are no dependencies on any external library. There are functions to decode and encode a PNG with a single function call, and extended versions of these functions taking a LodePNGState struct allowing to specify or get more information. By default the colors of the raw image are always RGB or RGBA, no matter what color type the PNG file uses. To read and write files, there are simple functions to convert the files to/from buffers in memory. This all makes LodePNG suitable for loading textures in games, demos and small programs, ... It's less suitable for full fledged image editors, loading PNGs over network (it requires all the image data to be available before decoding can begin), life-critical systems, ... 1.1. supported features ----------------------- The following features are supported by the decoder: *) decoding of PNGs with any color type, bit depth and interlace mode, to a 24- or 32-bit color raw image, or the same color type as the PNG *) encoding of PNGs, from any raw image to 24- or 32-bit color, or the same color type as the raw image *) Adam7 interlace and deinterlace for any color type *) loading the image from harddisk or decoding it from a buffer from other sources than harddisk *) support for alpha channels, including RGBA color model, translucent palettes and color keying *) zlib decompression (inflate) *) zlib compression (deflate) *) CRC32 and ADLER32 checksums *) colorimetric color profile conversions: currently experimentally available in lodepng_util.cpp only, plus alternatively ability to pass on chroma/gamma/ICC profile information to other color management system. *) handling of unknown chunks, allowing making a PNG editor that stores custom and unknown chunks. *) the following chunks are supported by both encoder and decoder: IHDR: header information PLTE: color palette IDAT: pixel data IEND: the final chunk tRNS: transparency for palettized images tEXt: textual information zTXt: compressed textual information iTXt: international textual information bKGD: suggested background color pHYs: physical dimensions tIME: modification time cHRM: RGB chromaticities gAMA: RGB gamma correction iCCP: ICC color profile sRGB: rendering intent sBIT: significant bits 1.2. features not supported --------------------------- The following features are not (yet) supported: *) some features needed to make a conformant PNG-Editor might be still missing. *) partial loading/stream processing. All data must be available and is processed in one call. *) The hIST and sPLT public chunks are not (yet) supported but treated as unknown chunks 2. C and C++ version -------------------- The C version uses buffers allocated with alloc that you need to free() yourself. You need to use init and cleanup functions for each struct whenever using a struct from the C version to avoid exploits and memory leaks. The C++ version has extra functions with std::vectors in the interface and the lodepng::State class which is a LodePNGState with constructor and destructor. These files work without modification for both C and C++ compilers because all the additional C++ code is in "#ifdef __cplusplus" blocks that make C-compilers ignore it, and the C code is made to compile both with strict ISO C90 and C++. To use the C++ version, you need to rename the source file to lodepng.cpp (instead of lodepng.c), and compile it with a C++ compiler. To use the C version, you need to rename the source file to lodepng.c (instead of lodepng.cpp), and compile it with a C compiler. 3. Security ----------- Even if carefully designed, it's always possible that LodePNG contains possible exploits. If you discover one, please let me know, and it will be fixed. When using LodePNG, care has to be taken with the C version of LodePNG, as well as the C-style structs when working with C++. The following conventions are used for all C-style structs: -if a struct has a corresponding init function, always call the init function when making a new one -if a struct has a corresponding cleanup function, call it before the struct disappears to avoid memory leaks -if a struct has a corresponding copy function, use the copy function instead of "=". The destination must also be inited already. 4. Decoding ----------- Decoding converts a PNG compressed image to a raw pixel buffer. Most documentation on using the decoder is at its declarations in the header above. For C, simple decoding can be done with functions such as lodepng_decode32, and more advanced decoding can be done with the struct LodePNGState and lodepng_decode. For C++, all decoding can be done with the various lodepng::decode functions, and lodepng::State can be used for advanced features. When using the LodePNGState, it uses the following fields for decoding: *) LodePNGInfo info_png: it stores extra information about the PNG (the input) in here *) LodePNGColorMode info_raw: here you can say what color mode of the raw image (the output) you want to get *) LodePNGDecoderSettings decoder: you can specify a few extra settings for the decoder to use LodePNGInfo info_png -------------------- After decoding, this contains extra information of the PNG image, except the actual pixels, width and height because these are already gotten directly from the decoder functions. It contains for example the original color type of the PNG image, text comments, suggested background color, etc... More details about the LodePNGInfo struct are at its declaration documentation. LodePNGColorMode info_raw ------------------------- When decoding, here you can specify which color type you want the resulting raw image to be. If this is different from the colortype of the PNG, then the decoder will automatically convert the result. This conversion always works, except if you want it to convert a color PNG to grayscale or to a palette with missing colors. By default, 32-bit color is used for the result. LodePNGDecoderSettings decoder ------------------------------ The settings can be used to ignore the errors created by invalid CRC and Adler32 chunks, and to disable the decoding of tEXt chunks. There's also a setting color_convert, true by default. If false, no conversion is done, the resulting data will be as it was in the PNG (after decompression) and you'll have to puzzle the colors of the pixels together yourself using the color type information in the LodePNGInfo. 5. Encoding ----------- Encoding converts a raw pixel buffer to a PNG compressed image. Most documentation on using the encoder is at its declarations in the header above. For C, simple encoding can be done with functions such as lodepng_encode32, and more advanced decoding can be done with the struct LodePNGState and lodepng_encode. For C++, all encoding can be done with the various lodepng::encode functions, and lodepng::State can be used for advanced features. Like the decoder, the encoder can also give errors. However it gives less errors since the encoder input is trusted, the decoder input (a PNG image that could be forged by anyone) is not trusted. When using the LodePNGState, it uses the following fields for encoding: *) LodePNGInfo info_png: here you specify how you want the PNG (the output) to be. *) LodePNGColorMode info_raw: here you say what color type of the raw image (the input) has *) LodePNGEncoderSettings encoder: you can specify a few settings for the encoder to use LodePNGInfo info_png -------------------- When encoding, you use this the opposite way as when decoding: for encoding, you fill in the values you want the PNG to have before encoding. By default it's not needed to specify a color type for the PNG since it's automatically chosen, but it's possible to choose it yourself given the right settings. The encoder will not always exactly match the LodePNGInfo struct you give, it tries as close as possible. Some things are ignored by the encoder. The encoder uses, for example, the following settings from it when applicable: colortype and bitdepth, text chunks, time chunk, the color key, the palette, the background color, the interlace method, unknown chunks, ... When encoding to a PNG with colortype 3, the encoder will generate a PLTE chunk. If the palette contains any colors for which the alpha channel is not 255 (so there are translucent colors in the palette), it'll add a tRNS chunk. LodePNGColorMode info_raw ------------------------- You specify the color type of the raw image that you give to the input here, including a possible transparent color key and palette you happen to be using in your raw image data. By default, 32-bit color is assumed, meaning your input has to be in RGBA format with 4 bytes (unsigned chars) per pixel. LodePNGEncoderSettings encoder ------------------------------ The following settings are supported (some are in sub-structs): *) auto_convert: when this option is enabled, the encoder will automatically choose the smallest possible color mode (including color key) that can encode the colors of all pixels without information loss. *) btype: the block type for LZ77. 0 = uncompressed, 1 = fixed huffman tree, 2 = dynamic huffman tree (best compression). Should be 2 for proper compression. *) use_lz77: whether or not to use LZ77 for compressed block types. Should be true for proper compression. *) windowsize: the window size used by the LZ77 encoder (1 - 32768). Has value 2048 by default, but can be set to 32768 for better, but slow, compression. *) force_palette: if colortype is 2 or 6, you can make the encoder write a PLTE chunk if force_palette is true. This can used as suggested palette to convert to by viewers that don't support more than 256 colors (if those still exist) *) add_id: add text chunk "Encoder: LodePNG " to the image. *) text_compression: default 1. If 1, it'll store texts as zTXt instead of tEXt chunks. zTXt chunks use zlib compression on the text. This gives a smaller result on large texts but a larger result on small texts (such as a single program name). It's all tEXt or all zTXt though, there's no separate setting per text yet. 6. color conversions -------------------- An important thing to note about LodePNG, is that the color type of the PNG, and the color type of the raw image, are completely independent. By default, when you decode a PNG, you get the result as a raw image in the color type you want, no matter whether the PNG was encoded with a palette, grayscale or RGBA color. And if you encode an image, by default LodePNG will automatically choose the PNG color type that gives good compression based on the values of colors and amount of colors in the image. It can be configured to let you control it instead as well, though. To be able to do this, LodePNG does conversions from one color mode to another. It can convert from almost any color type to any other color type, except the following conversions: RGB to grayscale is not supported, and converting to a palette when the palette doesn't have a required color is not supported. This is not supported on purpose: this is information loss which requires a color reduction algorithm that is beyond the scope of a PNG encoder (yes, RGB to gray is easy, but there are multiple ways if you want to give some channels more weight). By default, when decoding, you get the raw image in 32-bit RGBA or 24-bit RGB color, no matter what color type the PNG has. And by default when encoding, LodePNG automatically picks the best color model for the output PNG, and expects the input image to be 32-bit RGBA or 24-bit RGB. So, unless you want to control the color format of the images yourself, you can skip this chapter. 6.1. PNG color types -------------------- A PNG image can have many color types, ranging from 1-bit color to 64-bit color, as well as palettized color modes. After the zlib decompression and unfiltering in the PNG image is done, the raw pixel data will have that color type and thus a certain amount of bits per pixel. If you want the output raw image after decoding to have another color type, a conversion is done by LodePNG. The PNG specification gives the following color types: 0: grayscale, bit depths 1, 2, 4, 8, 16 2: RGB, bit depths 8 and 16 3: palette, bit depths 1, 2, 4 and 8 4: grayscale with alpha, bit depths 8 and 16 6: RGBA, bit depths 8 and 16 Bit depth is the amount of bits per pixel per color channel. So the total amount of bits per pixel is: amount of channels * bitdepth. 6.2. color conversions ---------------------- As explained in the sections about the encoder and decoder, you can specify color types and bit depths in info_png and info_raw to change the default behaviour. If, when decoding, you want the raw image to be something else than the default, you need to set the color type and bit depth you want in the LodePNGColorMode, or the parameters colortype and bitdepth of the simple decoding function. If, when encoding, you use another color type than the default in the raw input image, you need to specify its color type and bit depth in the LodePNGColorMode of the raw image, or use the parameters colortype and bitdepth of the simple encoding function. If, when encoding, you don't want LodePNG to choose the output PNG color type but control it yourself, you need to set auto_convert in the encoder settings to false, and specify the color type you want in the LodePNGInfo of the encoder (including palette: it can generate a palette if auto_convert is true, otherwise not). If the input and output color type differ (whether user chosen or auto chosen), LodePNG will do a color conversion, which follows the rules below, and may sometimes result in an error. To avoid some confusion: -the decoder converts from PNG to raw image -the encoder converts from raw image to PNG -the colortype and bitdepth in LodePNGColorMode info_raw, are those of the raw image -the colortype and bitdepth in the color field of LodePNGInfo info_png, are those of the PNG -when encoding, the color type in LodePNGInfo is ignored if auto_convert is enabled, it is automatically generated instead -when decoding, the color type in LodePNGInfo is set by the decoder to that of the original PNG image, but it can be ignored since the raw image has the color type you requested instead -if the color type of the LodePNGColorMode and PNG image aren't the same, a conversion between the color types is done if the color types are supported. If it is not supported, an error is returned. If the types are the same, no conversion is done. -even though some conversions aren't supported, LodePNG supports loading PNGs from any colortype and saving PNGs to any colortype, sometimes it just requires preparing the raw image correctly before encoding. -both encoder and decoder use the same color converter. The function lodepng_convert does the color conversion. It is available in the interface but normally isn't needed since the encoder and decoder already call it. Non supported color conversions: -color to grayscale when non-gray pixels are present: no error is thrown, but the result will look ugly because only the red channel is taken (it assumes all three channels are the same in this case so ignores green and blue). The reason no error is given is to allow converting from three-channel grayscale images to one-channel even if there are numerical imprecisions. -anything to palette when the palette does not have an exact match for a from-color in it: in this case an error is thrown Supported color conversions: -anything to 8-bit RGB, 8-bit RGBA, 16-bit RGB, 16-bit RGBA -any gray or gray+alpha, to gray or gray+alpha -anything to a palette, as long as the palette has the requested colors in it -removing alpha channel -higher to smaller bitdepth, and vice versa If you want no color conversion to be done (e.g. for speed or control): -In the encoder, you can make it save a PNG with any color type by giving the raw color mode and LodePNGInfo the same color mode, and setting auto_convert to false. -In the decoder, you can make it store the pixel data in the same color type as the PNG has, by setting the color_convert setting to false. Settings in info_raw are then ignored. 6.3. padding bits ----------------- In the PNG file format, if a less than 8-bit per pixel color type is used and the scanlines have a bit amount that isn't a multiple of 8, then padding bits are used so that each scanline starts at a fresh byte. But that is NOT true for the LodePNG raw input and output. The raw input image you give to the encoder, and the raw output image you get from the decoder will NOT have these padding bits, e.g. in the case of a 1-bit image with a width of 7 pixels, the first pixel of the second scanline will the 8th bit of the first byte, not the first bit of a new byte. 6.4. A note about 16-bits per channel and endianness ---------------------------------------------------- LodePNG uses unsigned char arrays for 16-bit per channel colors too, just like for any other color format. The 16-bit values are stored in big endian (most significant byte first) in these arrays. This is the opposite order of the little endian used by x86 CPU's. LodePNG always uses big endian because the PNG file format does so internally. Conversions to other formats than PNG uses internally are not supported by LodePNG on purpose, there are myriads of formats, including endianness of 16-bit colors, the order in which you store R, G, B and A, and so on. Supporting and converting to/from all that is outside the scope of LodePNG. This may mean that, depending on your use case, you may want to convert the big endian output of LodePNG to little endian with a for loop. This is certainly not always needed, many applications and libraries support big endian 16-bit colors anyway, but it means you cannot simply cast the unsigned char* buffer to an unsigned short* buffer on x86 CPUs. 7. error values --------------- All functions in LodePNG that return an error code, return 0 if everything went OK, or a non-zero code if there was an error. The meaning of the LodePNG error values can be retrieved with the function lodepng_error_text: given the numerical error code, it returns a description of the error in English as a string. Check the implementation of lodepng_error_text to see the meaning of each code. It is not recommended to use the numerical values to programmatically make different decisions based on error types as the numbers are not guaranteed to stay backwards compatible. They are for human consumption only. Programmatically only 0 or non-0 matter. 8. chunks and PNG editing ------------------------- If you want to add extra chunks to a PNG you encode, or use LodePNG for a PNG editor that should follow the rules about handling of unknown chunks, or if your program is able to read other types of chunks than the ones handled by LodePNG, then that's possible with the chunk functions of LodePNG. A PNG chunk has the following layout: 4 bytes length 4 bytes type name length bytes data 4 bytes CRC 8.1. iterating through chunks ----------------------------- If you have a buffer containing the PNG image data, then the first chunk (the IHDR chunk) starts at byte number 8 of that buffer. The first 8 bytes are the signature of the PNG and are not part of a chunk. But if you start at byte 8 then you have a chunk, and can check the following things of it. NOTE: none of these functions check for memory buffer boundaries. To avoid exploits, always make sure the buffer contains all the data of the chunks. When using lodepng_chunk_next, make sure the returned value is within the allocated memory. unsigned lodepng_chunk_length(const unsigned char* chunk): Get the length of the chunk's data. The total chunk length is this length + 12. void lodepng_chunk_type(char type[5], const unsigned char* chunk): unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type): Get the type of the chunk or compare if it's a certain type unsigned char lodepng_chunk_critical(const unsigned char* chunk): unsigned char lodepng_chunk_private(const unsigned char* chunk): unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk): Check if the chunk is critical in the PNG standard (only IHDR, PLTE, IDAT and IEND are). Check if the chunk is private (public chunks are part of the standard, private ones not). Check if the chunk is safe to copy. If it's not, then, when modifying data in a critical chunk, unsafe to copy chunks of the old image may NOT be saved in the new one if your program doesn't handle that type of unknown chunk. unsigned char* lodepng_chunk_data(unsigned char* chunk): const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk): Get a pointer to the start of the data of the chunk. unsigned lodepng_chunk_check_crc(const unsigned char* chunk): void lodepng_chunk_generate_crc(unsigned char* chunk): Check if the crc is correct or generate a correct one. unsigned char* lodepng_chunk_next(unsigned char* chunk): const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk): Iterate to the next chunk. This works if you have a buffer with consecutive chunks. Note that these functions do no boundary checking of the allocated data whatsoever, so make sure there is enough data available in the buffer to be able to go to the next chunk. unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk): unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, unsigned length, const char* type, const unsigned char* data): These functions are used to create new chunks that are appended to the data in *out that has length *outsize. The append function appends an existing chunk to the new data. The create function creates a new chunk with the given parameters and appends it. Type is the 4-letter name of the chunk. 8.2. chunks in info_png ----------------------- The LodePNGInfo struct contains fields with the unknown chunk in it. It has 3 buffers (each with size) to contain 3 types of unknown chunks: the ones that come before the PLTE chunk, the ones that come between the PLTE and the IDAT chunks, and the ones that come after the IDAT chunks. It's necessary to make the distinction between these 3 cases because the PNG standard forces to keep the ordering of unknown chunks compared to the critical chunks, but does not force any other ordering rules. info_png.unknown_chunks_data[0] is the chunks before PLTE info_png.unknown_chunks_data[1] is the chunks after PLTE, before IDAT info_png.unknown_chunks_data[2] is the chunks after IDAT The chunks in these 3 buffers can be iterated through and read by using the same way described in the previous subchapter. When using the decoder to decode a PNG, you can make it store all unknown chunks if you set the option settings.remember_unknown_chunks to 1. By default, this option is off (0). The encoder will always encode unknown chunks that are stored in the info_png. If you need it to add a particular chunk that isn't known by LodePNG, you can use lodepng_chunk_append or lodepng_chunk_create to the chunk data in info_png.unknown_chunks_data[x]. Chunks that are known by LodePNG should not be added in that way. E.g. to make LodePNG add a bKGD chunk, set background_defined to true and add the correct parameters there instead. 9. compiler support ------------------- No libraries other than the current standard C library are needed to compile LodePNG. For the C++ version, only the standard C++ library is needed on top. Add the files lodepng.c(pp) and lodepng.h to your project, include lodepng.h where needed, and your program can read/write PNG files. It is compatible with C90 and up, and C++03 and up. If performance is important, use optimization when compiling! For both the encoder and decoder, this makes a large difference. Make sure that LodePNG is compiled with the same compiler of the same version and with the same settings as the rest of the program, or the interfaces with std::vectors and std::strings in C++ can be incompatible. CHAR_BITS must be 8 or higher, because LodePNG uses unsigned chars for octets. *) gcc and g++ LodePNG is developed in gcc so this compiler is natively supported. It gives no warnings with compiler options "-Wall -Wextra -pedantic -ansi", with gcc and g++ version 4.7.1 on Linux, 32-bit and 64-bit. *) Clang Fully supported and warning-free. *) Mingw The Mingw compiler (a port of gcc for Windows) should be fully supported by LodePNG. *) Visual Studio and Visual C++ Express Edition LodePNG should be warning-free with warning level W4. Two warnings were disabled with pragmas though: warning 4244 about implicit conversions, and warning 4996 where it wants to use a non-standard function fopen_s instead of the standard C fopen. Visual Studio may want "stdafx.h" files to be included in each source file and give an error "unexpected end of file while looking for precompiled header". This is not standard C++ and will not be added to the stock LodePNG. You can disable it for lodepng.cpp only by right clicking it, Properties, C/C++, Precompiled Headers, and set it to Not Using Precompiled Headers there. NOTE: Modern versions of VS should be fully supported, but old versions, e.g. VS6, are not guaranteed to work. *) Compilers on Macintosh LodePNG has been reported to work both with gcc and LLVM for Macintosh, both for C and C++. *) Other Compilers If you encounter problems on any compilers, feel free to let me know and I may try to fix it if the compiler is modern and standards compliant. 10. examples ------------ This decoder example shows the most basic usage of LodePNG. More complex examples can be found on the LodePNG website. NOTE: these examples do not support wide-character filenames, you can use an external method to handle such files and encode or decode in-memory 10.1. decoder C++ example ------------------------- #include "lodepng.h" #include int main(int argc, char *argv[]) { const char* filename = argc > 1 ? argv[1] : "test.png"; //load and decode std::vector image; unsigned width, height; unsigned error = lodepng::decode(image, width, height, filename); //if there's an error, display it if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl; //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ... } 10.2. decoder C example ----------------------- #include "lodepng.h" int main(int argc, char *argv[]) { unsigned error; unsigned char* image; size_t width, height; const char* filename = argc > 1 ? argv[1] : "test.png"; error = lodepng_decode32_file(&image, &width, &height, filename); if(error) printf("decoder error %u: %s\n", error, lodepng_error_text(error)); / * use image here * / free(image); return 0; } 11. state settings reference ---------------------------- A quick reference of some settings to set on the LodePNGState For decoding: state.decoder.zlibsettings.ignore_adler32: ignore ADLER32 checksums state.decoder.zlibsettings.custom_...: use custom inflate function state.decoder.ignore_crc: ignore CRC checksums state.decoder.ignore_critical: ignore unknown critical chunks state.decoder.ignore_end: ignore missing IEND chunk. May fail if this corruption causes other errors state.decoder.color_convert: convert internal PNG color to chosen one state.decoder.read_text_chunks: whether to read in text metadata chunks state.decoder.remember_unknown_chunks: whether to read in unknown chunks state.info_raw.colortype: desired color type for decoded image state.info_raw.bitdepth: desired bit depth for decoded image state.info_raw....: more color settings, see struct LodePNGColorMode state.info_png....: no settings for decoder but output, see struct LodePNGInfo For encoding: state.encoder.zlibsettings.btype: disable compression by setting it to 0 state.encoder.zlibsettings.use_lz77: use LZ77 in compression state.encoder.zlibsettings.windowsize: tweak LZ77 windowsize state.encoder.zlibsettings.minmatch: tweak min LZ77 length to match state.encoder.zlibsettings.nicematch: tweak LZ77 match where to stop searching state.encoder.zlibsettings.lazymatching: try one more LZ77 matching state.encoder.zlibsettings.custom_...: use custom deflate function state.encoder.auto_convert: choose optimal PNG color type, if 0 uses info_png state.encoder.filter_palette_zero: PNG filter strategy for palette state.encoder.filter_strategy: PNG filter strategy to encode with state.encoder.force_palette: add palette even if not encoding to one state.encoder.add_id: add LodePNG identifier and version as a text chunk state.encoder.text_compression: use compressed text chunks for metadata state.info_raw.colortype: color type of raw input image you provide state.info_raw.bitdepth: bit depth of raw input image you provide state.info_raw: more color settings, see struct LodePNGColorMode state.info_png.color.colortype: desired color type if auto_convert is false state.info_png.color.bitdepth: desired bit depth if auto_convert is false state.info_png.color....: more color settings, see struct LodePNGColorMode state.info_png....: more PNG related settings, see struct LodePNGInfo 12. changes ----------- The version number of LodePNG is the date of the change given in the format yyyymmdd. Some changes aren't backwards compatible. Those are indicated with a (!) symbol. Not all changes are listed here, the commit history in github lists more: https://github.com/lvandeve/lodepng *) 6 may 2025 (!): renamed mDCv to mDCV and cLLi to cLLI as per the recent rename in the draft png third edition spec. Please note that as long as the third edition is not finalized, backwards-incompatible changes to its features are possible. *) 23 dec 2024: added support for the mDCv and cLLi chunks (for png third edition spec) *) 22 dec 2024: added support for the cICP chunk (for png third edition spec) *) 15 dec 2024: added support for the eXIf chunk (for png third edition spec) *) 10 apr 2023: faster CRC32 implementation, but with larger lookup table. *) 13 jun 2022: added support for the sBIT chunk. *) 09 jan 2022: minor decoder speed improvements. *) 27 jun 2021: added warnings that file reading/writing functions don't support wide-character filenames (support for this is not planned, opening files is not the core part of PNG decoding/decoding and is platform dependent). *) 17 oct 2020: prevent decoding too large text/icc chunks by default. *) 06 mar 2020: simplified some of the dynamic memory allocations. *) 12 jan 2020: (!) added 'end' argument to lodepng_chunk_next to allow correct overflow checks. *) 14 aug 2019: around 25% faster decoding thanks to huffman lookup tables. *) 15 jun 2019: (!) auto_choose_color API changed (for bugfix: don't use palette if gray ICC profile) and non-ICC LodePNGColorProfile renamed to LodePNGColorStats. *) 30 dec 2018: code style changes only: removed newlines before opening braces. *) 10 sep 2018: added way to inspect metadata chunks without full decoding. *) 19 aug 2018: (!) fixed color mode bKGD is encoded with and made it use palette index in case of palette. *) 10 aug 2018: (!) added support for gAMA, cHRM, sRGB and iCCP chunks. This change is backwards compatible unless you relied on unknown_chunks for those. *) 11 jun 2018: less restrictive check for pixel size integer overflow *) 14 jan 2018: allow optionally ignoring a few more recoverable errors *) 17 sep 2017: fix memory leak for some encoder input error cases *) 27 nov 2016: grey+alpha auto color model detection bugfix *) 18 apr 2016: Changed qsort to custom stable sort (for platforms w/o qsort). *) 09 apr 2016: Fixed colorkey usage detection, and better file loading (within the limits of pure C90). *) 08 dec 2015: Made load_file function return error if file can't be opened. *) 24 oct 2015: Bugfix with decoding to palette output. *) 18 apr 2015: Boundary PM instead of just package-merge for faster encoding. *) 24 aug 2014: Moved to github *) 23 aug 2014: Reduced needless memory usage of decoder. *) 28 jun 2014: Removed fix_png setting, always support palette OOB for simplicity. Made ColorProfile public. *) 09 jun 2014: Faster encoder by fixing hash bug and more zeros optimization. *) 22 dec 2013: Power of two windowsize required for optimization. *) 15 apr 2013: Fixed bug with LAC_ALPHA and color key. *) 25 mar 2013: Added an optional feature to ignore some PNG errors (fix_png). *) 11 mar 2013: (!) Bugfix with custom free. Changed from "my" to "lodepng_" prefix for the custom allocators and made it possible with a new #define to use custom ones in your project without needing to change lodepng's code. *) 28 jan 2013: Bugfix with color key. *) 27 oct 2012: Tweaks in text chunk keyword length error handling. *) 8 oct 2012: (!) Added new filter strategy (entropy) and new auto color mode. (no palette). Better deflate tree encoding. New compression tweak settings. Faster color conversions while decoding. Some internal cleanups. *) 23 sep 2012: Reduced warnings in Visual Studio a little bit. *) 1 sep 2012: (!) Removed #define's for giving custom (de)compression functions and made it work with function pointers instead. *) 23 jun 2012: Added more filter strategies. Made it easier to use custom alloc and free functions and toggle #defines from compiler flags. Small fixes. *) 6 may 2012: (!) Made plugging in custom zlib/deflate functions more flexible. *) 22 apr 2012: (!) Made interface more consistent, renaming a lot. Removed redundant C++ codec classes. Reduced amount of structs. Everything changed, but it is cleaner now imho and functionality remains the same. Also fixed several bugs and shrunk the implementation code. Made new samples. *) 6 nov 2011: (!) By default, the encoder now automatically chooses the best PNG color model and bit depth, based on the amount and type of colors of the raw image. For this, autoLeaveOutAlphaChannel replaced by auto_choose_color. *) 9 oct 2011: simpler hash chain implementation for the encoder. *) 8 sep 2011: lz77 encoder lazy matching instead of greedy matching. *) 23 aug 2011: tweaked the zlib compression parameters after benchmarking. A bug with the PNG filtertype heuristic was fixed, so that it chooses much better ones (it's quite significant). A setting to do an experimental, slow, brute force search for PNG filter types is added. *) 17 aug 2011: (!) changed some C zlib related function names. *) 16 aug 2011: made the code less wide (max 120 characters per line). *) 17 apr 2011: code cleanup. Bugfixes. Convert low to 16-bit per sample colors. *) 21 feb 2011: fixed compiling for C90. Fixed compiling with sections disabled. *) 11 dec 2010: encoding is made faster, based on suggestion by Peter Eastman to optimize long sequences of zeros. *) 13 nov 2010: added LodePNG_InfoColor_hasPaletteAlpha and LodePNG_InfoColor_canHaveAlpha functions for convenience. *) 7 nov 2010: added LodePNG_error_text function to get error code description. *) 30 oct 2010: made decoding slightly faster *) 26 oct 2010: (!) changed some C function and struct names (more consistent). Reorganized the documentation and the declaration order in the header. *) 08 aug 2010: only changed some comments and external samples. *) 05 jul 2010: fixed bug thanks to warnings in the new gcc version. *) 14 mar 2010: fixed bug where too much memory was allocated for char buffers. *) 02 sep 2008: fixed bug where it could create empty tree that linux apps could read by ignoring the problem but windows apps couldn't. *) 06 jun 2008: added more error checks for out of memory cases. *) 26 apr 2008: added a few more checks here and there to ensure more safety. *) 06 mar 2008: crash with encoding of strings fixed *) 02 feb 2008: support for international text chunks added (iTXt) *) 23 jan 2008: small cleanups, and #defines to divide code in sections *) 20 jan 2008: support for unknown chunks allowing using LodePNG for an editor. *) 18 jan 2008: support for tIME and pHYs chunks added to encoder and decoder. *) 17 jan 2008: ability to encode and decode compressed zTXt chunks added Also various fixes, such as in the deflate and the padding bits code. *) 13 jan 2008: Added ability to encode Adam7-interlaced images. Improved filtering code of encoder. *) 07 jan 2008: (!) changed LodePNG to use ISO C90 instead of C++. A C++ wrapper around this provides an interface almost identical to before. Having LodePNG be pure ISO C90 makes it more portable. The C and C++ code are together in these files but it works both for C and C++ compilers. *) 29 dec 2007: (!) changed most integer types to unsigned int + other tweaks *) 30 aug 2007: bug fixed which makes this Borland C++ compatible *) 09 aug 2007: some VS2005 warnings removed again *) 21 jul 2007: deflate code placed in new namespace separate from zlib code *) 08 jun 2007: fixed bug with 2- and 4-bit color, and small interlaced images *) 04 jun 2007: improved support for Visual Studio 2005: crash with accessing invalid std::vector element [0] fixed, and level 3 and 4 warnings removed *) 02 jun 2007: made the encoder add a tag with version by default *) 27 may 2007: zlib and png code separated (but still in the same file), simple encoder/decoder functions added for more simple usage cases *) 19 may 2007: minor fixes, some code cleaning, new error added (error 69), moved some examples from here to lodepng_examples.cpp *) 12 may 2007: palette decoding bug fixed *) 24 apr 2007: changed the license from BSD to the zlib license *) 11 mar 2007: very simple addition: ability to encode bKGD chunks. *) 04 mar 2007: (!) tEXt chunk related fixes, and support for encoding palettized PNG images. Plus little interface change with palette and texts. *) 03 mar 2007: Made it encode dynamic Huffman shorter with repeat codes. Fixed a bug where the end code of a block had length 0 in the Huffman tree. *) 26 feb 2007: Huffman compression with dynamic trees (BTYPE 2) now implemented and supported by the encoder, resulting in smaller PNGs at the output. *) 27 jan 2007: Made the Adler-32 test faster so that a timewaste is gone. *) 24 jan 2007: gave encoder an error interface. Added color conversion from any greyscale type to 8-bit greyscale with or without alpha. *) 21 jan 2007: (!) Totally changed the interface. It allows more color types to convert to and is more uniform. See the manual for how it works now. *) 07 jan 2007: Some cleanup & fixes, and a few changes over the last days: encode/decode custom tEXt chunks, separate classes for zlib & deflate, and at last made the decoder give errors for incorrect Adler32 or Crc. *) 01 jan 2007: Fixed bug with encoding PNGs with less than 8 bits per channel. *) 29 dec 2006: Added support for encoding images without alpha channel, and cleaned out code as well as making certain parts faster. *) 28 dec 2006: Added "Settings" to the encoder. *) 26 dec 2006: The encoder now does LZ77 encoding and produces much smaller files now. Removed some code duplication in the decoder. Fixed little bug in an example. *) 09 dec 2006: (!) Placed output parameters of public functions as first parameter. Fixed a bug of the decoder with 16-bit per color. *) 15 oct 2006: Changed documentation structure *) 09 oct 2006: Encoder class added. It encodes a valid PNG image from the given image buffer, however for now it's not compressed. *) 08 sep 2006: (!) Changed to interface with a Decoder class *) 30 jul 2006: (!) LodePNG_InfoPng , width and height are now retrieved in different way. Renamed decodePNG to decodePNGGeneric. *) 29 jul 2006: (!) Changed the interface: image info is now returned as a struct of type LodePNG::LodePNG_Info, instead of a vector, which was a bit clumsy. *) 28 jul 2006: Cleaned the code and added new error checks. Corrected terminology "deflate" into "inflate". *) 23 jun 2006: Added SDL example in the documentation in the header, this example allows easy debugging by displaying the PNG and its transparency. *) 22 jun 2006: (!) Changed way to obtain error value. Added loadFile function for convenience. Made decodePNG32 faster. *) 21 jun 2006: (!) Changed type of info vector to unsigned. Changed position of palette in info vector. Fixed an important bug that happened on PNGs with an uncompressed block. *) 16 jun 2006: Internally changed unsigned into unsigned where needed, and performed some optimizations. *) 07 jun 2006: (!) Renamed functions to decodePNG and placed them in LodePNG namespace. Changed the order of the parameters. Rewrote the documentation in the header. Renamed files to lodepng.cpp and lodepng.h *) 22 apr 2006: Optimized and improved some code *) 07 sep 2005: (!) Changed to std::vector interface *) 12 aug 2005: Initial release (C++, decoder only) */ ================================================ FILE: src/main.cpp ================================================ #include "pdvzip.h" namespace { int run(int argc, char** argv) { auto args = ProgramArgs::parse(argc, argv); if (args.info_mode) { displayInfo(); return 0; } vBytes image_vec = readFile(*args.image_file_path, FileTypeCheck::cover_image); vBytes archive_vec = readFile(*args.archive_file_path); optimizeImage(image_vec); const std::size_t original_image_size = image_vec.size(); const std::size_t archive_file_size = archive_vec.size(); const bool is_zip_file = hasFileExtension(*args.archive_file_path, {".zip"}); // Update the IDAT chunk length to include the archive. writeValueAt(archive_vec, 0, archive_file_size - CHUNK_FIELDS_COMBINED_LENGTH, 4); // Reject unsafe archive entry paths (zip-slip style traversal/absolute paths). validateArchiveEntryPaths(archive_vec); // Determine what kind of file is embedded and capture the first archive path. const ArchiveMetadata archive_metadata = analyzeArchive(archive_vec, is_zip_file); // Prompt for optional arguments (scripts, executables, JAR). const UserArguments user_args = promptForArguments(archive_metadata.file_type); // Build the iCCP chunk containing the extraction script. vBytes script_vec = buildExtractionScript(archive_metadata.file_type, archive_metadata.first_filename, user_args); // Assemble the polyglot: embed script + archive, fix offsets, finalize CRC. embedChunks(image_vec, std::move(script_vec), std::move(archive_vec), original_image_size); writePolyglotFile(image_vec, is_zip_file); return 0; } } // anonymous namespace int main(int argc, char** argv) { try { return run(argc, argv); } catch (const std::exception& e) { std::println(std::cerr, "\n{}\n", e.what()); return 1; } } ================================================ FILE: src/pdvzip.h ================================================ // PNG Data Vehicle, ZIP/JAR Edition (PDVZIP v4.5) // Created by Nicholas Cleasby (@CleasbyCode) 6/08/2022 #pragma once #include "lodepng/lodepng.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include namespace fs = std::filesystem; using Byte = std::uint8_t; using vBytes = std::vector; using std::operator""sv; enum class FileTypeCheck : Byte { cover_image = 1, archive_file = 2 }; enum class FileType : std::size_t { VIDEO_AUDIO = 29, PDF, PYTHON, POWERSHELL, BASH_SHELL, WINDOWS_EXECUTABLE, UNKNOWN_FILE_TYPE, FOLDER, LINUX_EXECUTABLE, JAR }; constexpr auto EXTENSION_LIST = std::to_array({ "mp4", "mp3", "wav", "mpg", "webm", "flac", "3gp", "aac", "aiff", "aif", "alac", "ape", "avchd", "avi", "dsd", "divx", "f4v", "flv", "m4a", "m4v", "mkv", "mov", "midi", "mpeg", "ogg", "pcm", "swf", "wma", "wmv", "xvid", "pdf", "py", "ps1", "sh", "exe" }); constexpr Byte INDEXED_PLTE = 3, TRUECOLOR_RGB = 2, TRUECOLOR_RGBA = 6; constexpr std::size_t CHUNK_FIELDS_COMBINED_LENGTH = 12, MAX_SCRIPT_SIZE = 1500; constexpr uint32_t ZIP_LOCAL_FILE_HEADER_SIGNATURE = 0x04034B50, ZIP_CENTRAL_DIRECTORY_SIGNATURE = 0x02014B50, ZIP_END_CENTRAL_DIRECTORY_SIGNATURE = 0x06054B50, ZIP_DATA_DESCRIPTOR_SIGNATURE = 0x08074B50; // Metacharacters that can break bash parsing or redirect before execution reaches // the embedded extraction script. constexpr auto LINUX_PROBLEM_METACHARACTERS = std::to_array({ 0x22, 0x27, 0x28, 0x29, 0x3B, 0x3E, 0x60 }); struct UserArguments { std::string linux_args; std::string windows_args; }; struct ProgramArgs { std::optional image_file_path; std::optional archive_file_path; bool info_mode = false; static ProgramArgs parse(int argc, char** argv); }; // display_info.cpp void displayInfo(); // file_io.cpp [[nodiscard]] bool hasValidFilename(const fs::path& p); [[nodiscard]] bool hasFileExtension(const fs::path& p, std::initializer_list exts); [[nodiscard]] vBytes readFile(const fs::path& path, FileTypeCheck check_type = FileTypeCheck::archive_file); void writePolyglotFile(const vBytes& image_vec, bool is_zip_file); // binary_utils.cpp void writeValueAt( std::span data, std::size_t offset, std::size_t value, std::size_t length, std::endian byte_order = std::endian::big); [[nodiscard]] std::size_t readValueAt( std::span data, std::size_t offset, std::size_t length, std::endian byte_order = std::endian::big); [[nodiscard]] std::size_t checkedAdd(std::size_t lhs, std::size_t rhs, std::string_view context); [[nodiscard]] std::size_t checkedMultiply(std::size_t lhs, std::size_t rhs, std::string_view context); namespace binary_utils_detail { [[noreturn]] void throwOutOfRange(std::string_view fn_name); } [[nodiscard]] inline uint16_t readLe16(std::span data, std::size_t offset) { if (offset > data.size() || data.size() - offset < 2) { binary_utils_detail::throwOutOfRange("readLe16"); } return static_cast( static_cast(data[offset]) | (static_cast(data[offset + 1]) << 8)); } [[nodiscard]] inline uint32_t readLe32(std::span data, std::size_t offset) { if (offset > data.size() || data.size() - offset < 4) { binary_utils_detail::throwOutOfRange("readLe32"); } return static_cast(data[offset]) | (static_cast(data[offset + 1]) << 8) | (static_cast(data[offset + 2]) << 16) | (static_cast(data[offset + 3]) << 24); } inline void writeLe16(std::span data, std::size_t offset, uint16_t value) { if (offset > data.size() || data.size() - offset < 2) { binary_utils_detail::throwOutOfRange("writeLe16"); } data[offset] = static_cast(value & 0xFF); data[offset + 1] = static_cast((value >> 8) & 0xFF); } inline void writeLe32(std::span data, std::size_t offset, uint32_t value) { if (offset > data.size() || data.size() - offset < 4) { binary_utils_detail::throwOutOfRange("writeLe32"); } data[offset] = static_cast(value & 0xFF); data[offset + 1] = static_cast((value >> 8) & 0xFF); data[offset + 2] = static_cast((value >> 16) & 0xFF); data[offset + 3] = static_cast((value >> 24) & 0xFF); } [[nodiscard]] inline bool hasLe32Signature(std::span data, std::size_t offset, uint32_t signature) { return offset <= data.size() && data.size() - offset >= 4 && readLe32(data, offset) == signature; } [[nodiscard]] inline bool isLinuxProblemMetacharacter(Byte value) { return std::ranges::contains(LINUX_PROBLEM_METACHARACTERS, value); } struct ZipEocdLocator { std::size_t index; uint16_t comment_length; }; [[nodiscard]] std::optional findZipEocdLocator( std::span data, std::size_t archive_begin, std::size_t archive_end); // image_processing.cpp void optimizeImage(vBytes& image_file_vec); // archive_analysis.cpp struct ArchiveMetadata { FileType file_type; std::string first_filename; }; ArchiveMetadata analyzeArchive(std::span archive_data, bool is_zip_file); void validateArchiveEntryPaths(std::span archive_data); // user_input.cpp UserArguments promptForArguments(FileType file_type); // script_builder.cpp vBytes buildExtractionScript( FileType file_type, const std::string& first_filename, const UserArguments& user_args); // polyglot_assembly.cpp void embedChunks(vBytes& image_vec, vBytes script_vec, vBytes archive_vec, std::size_t original_image_size); ================================================ FILE: src/polyglot_assembly.cpp ================================================ #include "pdvzip.h" namespace { constexpr std::size_t ICCP_CHUNK_INDEX = 0x21, VALUE_BYTE_LENGTH_FOUR = 4, ARCHIVE_INSERT_INDEX_DIFF = 12, EXCLUDE_SIZE_AND_CRC_LENGTH = 8, LAST_IDAT_INDEX_DIFF = 4, LAST_IDAT_CRC_INDEX_DIFF = 16; struct ZipEocdInfo { std::size_t index; uint16_t total_records; uint32_t central_size; uint32_t central_offset; uint16_t comment_length; }; [[nodiscard]] ZipEocdInfo findZipEocd( std::span image_vec, std::size_t zip_base_offset, std::size_t zip_end_offset) { constexpr std::size_t EOCD_MIN_SIZE = 22, EOCD_DISK_NUMBER_OFFSET = 4, EOCD_CENTRAL_DISK_OFFSET = 6, EOCD_RECORDS_ON_DISK = 8, EOCD_TOTAL_RECORDS_OFFSET = 10, EOCD_CENTRAL_SIZE_OFFSET = 12, EOCD_CENTRAL_OFFSET = 16; if (zip_end_offset > image_vec.size() || zip_end_offset < zip_base_offset || zip_end_offset - zip_base_offset < EOCD_MIN_SIZE) { throw std::runtime_error("ZIP Error: Archive is too small."); } const auto locator = findZipEocdLocator(image_vec, zip_base_offset, zip_end_offset); if (!locator) { throw std::runtime_error("ZIP Error: End of Central Directory signature not found."); } const std::size_t pos = locator->index; const auto info = ZipEocdInfo{ .index = pos, .total_records = readLe16(image_vec, pos + EOCD_TOTAL_RECORDS_OFFSET), .central_size = readLe32(image_vec, pos + EOCD_CENTRAL_SIZE_OFFSET), .central_offset = readLe32(image_vec, pos + EOCD_CENTRAL_OFFSET), .comment_length = locator->comment_length, }; const uint16_t disk_number = readLe16(image_vec, pos + EOCD_DISK_NUMBER_OFFSET); const uint16_t central_disk = readLe16(image_vec, pos + EOCD_CENTRAL_DISK_OFFSET); const uint16_t records_on_disk = readLe16(image_vec, pos + EOCD_RECORDS_ON_DISK); if (disk_number != 0 || central_disk != 0 || records_on_disk != info.total_records || info.total_records == UINT16_MAX || info.central_size == UINT32_MAX || info.central_offset == UINT32_MAX) { throw std::runtime_error("ZIP Error: ZIP64 or multi-disk archives are not supported."); } if (info.total_records == 0) { throw std::runtime_error("ZIP Error: Archive contains no records."); } const std::size_t central_start = checkedAdd( zip_base_offset, static_cast(info.central_offset), "ZIP Error: Central directory offset overflow."); const std::size_t central_end = checkedAdd( central_start, static_cast(info.central_size), "ZIP Error: Central directory size overflow."); if (central_start > zip_end_offset || central_end > zip_end_offset || central_end != pos) { throw std::runtime_error("ZIP Error: Central directory bounds are invalid."); } return info; } // Fix all ZIP record offsets so the archive remains valid after being embedded // behind the PNG wrapper bytes. void fixZipOffsets(vBytes& image_vec, std::size_t original_image_size, std::size_t script_data_size) { constexpr std::size_t ZIP_BASE_SHIFT = 8, PNG_TRAILING_BYTES = 16, CENTRAL_RECORD_MIN_SIZE = 46, CENTRAL_NAME_LENGTH_OFFSET = 28, CENTRAL_EXTRA_LENGTH_OFFSET = 30, CENTRAL_COMMENT_LENGTH_OFFSET = 32, CENTRAL_DISK_START_OFFSET = 34, CENTRAL_LOCAL_OFFSET_OFFSET = 42; const std::size_t zip_base_offset = checkedAdd( checkedAdd(original_image_size, script_data_size, "ZIP Error: Base offset overflow."), ZIP_BASE_SHIFT, "ZIP Error: Base offset overflow."); if (image_vec.size() < PNG_TRAILING_BYTES) { throw std::runtime_error("ZIP Error: Embedded image is truncated."); } const std::size_t zip_end_offset = image_vec.size() - PNG_TRAILING_BYTES; const ZipEocdInfo eocd = findZipEocd(image_vec, zip_base_offset, zip_end_offset); const std::size_t central_start = checkedAdd( zip_base_offset, static_cast(eocd.central_offset), "ZIP Error: Central directory offset overflow."); const std::size_t central_end = checkedAdd( central_start, static_cast(eocd.central_size), "ZIP Error: Central directory size overflow."); if (central_start > zip_end_offset || central_end > zip_end_offset || central_end != eocd.index) { throw std::runtime_error("ZIP Error: Central directory bounds are invalid."); } if (central_start > UINT32_MAX) { throw std::runtime_error("ZIP Error: Central directory offset exceeds ZIP32 limits."); } if (eocd.comment_length > UINT16_MAX - PNG_TRAILING_BYTES) { throw std::runtime_error("ZIP Error: Comment length overflow."); } writeLe16(image_vec, eocd.index + 20, static_cast(eocd.comment_length + PNG_TRAILING_BYTES)); writeLe32(image_vec, eocd.index + 16, static_cast(central_start)); std::size_t cursor = central_start; for (uint16_t i = 0; i < eocd.total_records; ++i) { if (cursor > image_vec.size() || CENTRAL_RECORD_MIN_SIZE > image_vec.size() - cursor) { throw std::runtime_error("ZIP Error: Truncated central directory file header."); } if (!hasLe32Signature(image_vec, cursor, ZIP_CENTRAL_DIRECTORY_SIGNATURE)) { throw std::runtime_error(std::format( "ZIP Error: Invalid central directory file header signature at record {}.", i + 1)); } const std::size_t name_length = readLe16(image_vec, cursor + CENTRAL_NAME_LENGTH_OFFSET); const std::size_t extra_length = readLe16(image_vec, cursor + CENTRAL_EXTRA_LENGTH_OFFSET); const std::size_t comment_length = readLe16(image_vec, cursor + CENTRAL_COMMENT_LENGTH_OFFSET); const uint16_t entry_disk_start = readLe16(image_vec, cursor + CENTRAL_DISK_START_OFFSET); const std::size_t record_size = CENTRAL_RECORD_MIN_SIZE + name_length + extra_length + comment_length; if (entry_disk_start != 0) { throw std::runtime_error(std::format( "ZIP Error: Multi-disk local header reference on record {} is not supported.", i + 1)); } if (record_size > image_vec.size() - cursor || cursor + record_size > central_end) { throw std::runtime_error("ZIP Error: Central directory entry exceeds archive bounds."); } const std::size_t local_offset = checkedAdd( zip_base_offset, static_cast(readLe32(image_vec, cursor + CENTRAL_LOCAL_OFFSET_OFFSET)), "ZIP Error: Local file header offset overflow."); if (local_offset > UINT32_MAX) { throw std::runtime_error("ZIP Error: Local file header offset exceeds ZIP32 limits."); } if (local_offset >= central_start || 4 > image_vec.size() - local_offset) { throw std::runtime_error("ZIP Error: Local file header offset is out of bounds."); } if (!hasLe32Signature(image_vec, local_offset, ZIP_LOCAL_FILE_HEADER_SIGNATURE)) { throw std::runtime_error(std::format( "ZIP Error: Local file header signature mismatch for record {}.", i + 1)); } writeLe32(image_vec, cursor + CENTRAL_LOCAL_OFFSET_OFFSET, static_cast(local_offset)); cursor += record_size; } if (cursor != central_end) { throw std::runtime_error("ZIP Error: Central directory size does not match parsed records."); } } void validateEmbedInputs(const vBytes& image_vec, const vBytes& script_vec, const vBytes& archive_vec) { if (image_vec.size() < ICCP_CHUNK_INDEX || image_vec.size() < ARCHIVE_INSERT_INDEX_DIFF) { throw std::runtime_error("Embed Error: Optimized PNG is too small for chunk insertion."); } if (script_vec.size() < CHUNK_FIELDS_COMBINED_LENGTH) { throw std::runtime_error("Embed Error: Script chunk is truncated."); } if (archive_vec.size() < CHUNK_FIELDS_COMBINED_LENGTH) { throw std::runtime_error("Embed Error: Archive chunk is truncated."); } } void reserveEmbeddedImageSize(vBytes& image_vec, std::size_t script_size, std::size_t archive_size) { const std::size_t output_size = checkedAdd( checkedAdd(image_vec.size(), script_size, "Embed Error: Output image size overflow."), archive_size, "Embed Error: Output image size overflow."); image_vec.reserve(output_size); } void insertScriptChunk(vBytes& image_vec, const vBytes& script_vec) { image_vec.insert(image_vec.begin() + ICCP_CHUNK_INDEX, script_vec.begin(), script_vec.end()); } void insertArchiveChunk(vBytes& image_vec, const vBytes& archive_vec) { image_vec.insert(image_vec.end() - ARCHIVE_INSERT_INDEX_DIFF, archive_vec.begin(), archive_vec.end()); } void writeLastIdatCrc( vBytes& image_vec, std::size_t original_image_size, std::size_t script_data_size, std::size_t archive_file_size) { const std::size_t last_idat_index = checkedAdd( checkedAdd(original_image_size, script_data_size, "Embed Error: IDAT index overflow."), LAST_IDAT_INDEX_DIFF, "Embed Error: IDAT index overflow."); const std::size_t complete_size = image_vec.size(); if (archive_file_size < EXCLUDE_SIZE_AND_CRC_LENGTH) { throw std::runtime_error("Embed Error: Archive too small for CRC computation."); } const std::size_t crc_length = archive_file_size - EXCLUDE_SIZE_AND_CRC_LENGTH; if (last_idat_index > complete_size || crc_length > complete_size - last_idat_index) { throw std::runtime_error("Embed Error: IDAT CRC region exceeds image bounds."); } const uint32_t last_idat_crc = lodepng_crc32(&image_vec[last_idat_index], crc_length); const std::size_t crc_index = complete_size - LAST_IDAT_CRC_INDEX_DIFF; writeValueAt(image_vec, crc_index, last_idat_crc, VALUE_BYTE_LENGTH_FOUR); } } // anonymous namespace // ============================================================================ // Public: Embed the script chunk and archive into the image // ============================================================================ void embedChunks(vBytes& image_vec, vBytes script_vec, vBytes archive_vec, std::size_t original_image_size) { validateEmbedInputs(image_vec, script_vec, archive_vec); const std::size_t script_data_size = script_vec.size() - CHUNK_FIELDS_COMBINED_LENGTH; const std::size_t archive_file_size = archive_vec.size(); reserveEmbeddedImageSize(image_vec, script_vec.size(), archive_vec.size()); // Insert iCCP script chunk after the PNG header. insertScriptChunk(image_vec, script_vec); script_vec = vBytes{}; // Release memory. // Insert archive data before the IEND chunk. insertArchiveChunk(image_vec, archive_vec); archive_vec = vBytes{}; // Release memory. // Fix ZIP internal offsets (must happen before CRC computation, // since the offsets are within the CRC-covered region). fixZipOffsets(image_vec, original_image_size, script_data_size); // Recompute the last IDAT chunk CRC. writeLastIdatCrc(image_vec, original_image_size, script_data_size, archive_file_size); } ================================================ FILE: src/program_args.cpp ================================================ #include "pdvzip.h" namespace { [[nodiscard]] bool isInfoModeRequest(int argc, char** argv) { return argc == 2 && argv[1] != nullptr && std::string_view(argv[1]) == "--info"; } [[nodiscard]] std::string usageFor(std::string_view program_name) { return std::format( "Usage: {} \n" " {} --info", program_name, program_name); } } // anonymous namespace ProgramArgs ProgramArgs::parse(int argc, char** argv) { if (argc < 1 || argv == nullptr || argv[0] == nullptr) { throw std::runtime_error("Invalid program invocation: missing program name"); } if (isInfoModeRequest(argc, argv)) { return ProgramArgs{ .image_file_path = {}, .archive_file_path = {}, .info_mode = true }; } if (argc != 3) { const std::string prog = fs::path(argv[0]).filename().string(); throw std::runtime_error(usageFor(prog)); } if (argv[1] == nullptr || argv[2] == nullptr) { throw std::runtime_error("Invalid program invocation: missing input path."); } return ProgramArgs{ .image_file_path = argv[1], .archive_file_path = argv[2], }; } ================================================ FILE: src/script_builder.cpp ================================================ #include "script_builder_internal.h" using script_builder_internal::buildScriptText; namespace { constexpr std::size_t SCRIPT_INDEX = 0x16; constexpr std::size_t ICCP_CHUNK_NAME_INDEX = 0x04; constexpr std::size_t ICCP_CHUNK_NAME_LENGTH = 4; constexpr std::size_t ICCP_CRC_INDEX_DIFF = 8; constexpr std::size_t LENGTH_FIRST_BYTE_INDEX = 3; constexpr std::size_t LENGTH_INDEX = 0; constexpr std::size_t VALUE_LENGTH = 4; constexpr std::size_t PAD_OFFSET = 8; constexpr std::size_t MAX_PAD_ATTEMPTS = 32; constexpr std::string_view PAD = "........"; [[nodiscard]] vBytes makeIccpChunkSkeleton() { return vBytes{ 0x00, 0x00, 0x00, 0x00, 0x69, 0x43, 0x43, 0x50, 0x44, 0x56, 0x5A, 0x49, 0x50, 0x5F, 0x5F, 0x00, 0x00, 0x0D, 0x52, 0x45, 0x4D, 0x3B, 0x0D, 0x0A, 0x00, 0x00, 0x00, 0x00 }; } void insertScriptText(vBytes& script_vec, std::string_view script_text) { script_vec.insert( script_vec.begin() + SCRIPT_INDEX, script_text.begin(), script_text.end()); } [[nodiscard]] std::size_t writeChunkLength(vBytes& script_vec) { const std::size_t chunk_data_size = script_vec.size() - CHUNK_FIELDS_COMBINED_LENGTH; writeValueAt(script_vec, LENGTH_INDEX, chunk_data_size, VALUE_LENGTH); return chunk_data_size; } void padChunkLengthUntilLinuxSafe(vBytes& script_vec, std::size_t& chunk_data_size) { std::size_t pad_attempts = 0; while (isLinuxProblemMetacharacter(script_vec[LENGTH_FIRST_BYTE_INDEX])) { if (++pad_attempts > MAX_PAD_ATTEMPTS) { throw std::runtime_error("Script Error: Could not make iCCP chunk length Linux-safe."); } script_vec.insert( script_vec.begin() + chunk_data_size + PAD_OFFSET, PAD.begin(), PAD.end()); chunk_data_size = script_vec.size() - CHUNK_FIELDS_COMBINED_LENGTH; writeValueAt(script_vec, LENGTH_INDEX, chunk_data_size, VALUE_LENGTH); } } void writeChunkCrc(vBytes& script_vec, std::size_t chunk_data_size) { const std::size_t iccp_chunk_length = chunk_data_size + ICCP_CHUNK_NAME_LENGTH; const uint32_t crc = lodepng_crc32(&script_vec[ICCP_CHUNK_NAME_INDEX], iccp_chunk_length); const std::size_t crc_index = chunk_data_size + ICCP_CRC_INDEX_DIFF; writeValueAt(script_vec, crc_index, crc, VALUE_LENGTH); } } // namespace // ============================================================================ // Public: Build the extraction script chunk (iCCP) // ============================================================================ vBytes buildExtractionScript( FileType file_type, const std::string& first_filename, const UserArguments& user_args) { vBytes script_vec = makeIccpChunkSkeleton(); script_vec.reserve(script_vec.size() + MAX_SCRIPT_SIZE); const std::string script_text = buildScriptText(file_type, first_filename, user_args); insertScriptText(script_vec, script_text); std::size_t chunk_data_size = writeChunkLength(script_vec); // If the first byte of the chunk length is a problematic metacharacter for // the Linux extraction script, pad the chunk until it lands on a safe byte. padChunkLengthUntilLinuxSafe(script_vec, chunk_data_size); if (chunk_data_size > MAX_SCRIPT_SIZE) { throw std::runtime_error("Script Size Error: Extraction script exceeds size limit."); } writeChunkCrc(script_vec, chunk_data_size); return script_vec; } ================================================ FILE: src/script_builder_internal.h ================================================ #pragma once #include "pdvzip.h" namespace script_builder_internal { std::string buildScriptText( FileType file_type, const std::string& first_filename, const UserArguments& user_args); } // namespace script_builder_internal ================================================ FILE: src/script_text_builder.cpp ================================================ #include "script_builder_internal.h" namespace { // ============================================================================ // Internal: Script templates (Linux + Windows pairs per file type) // ============================================================================ constexpr auto CRLF = "\r\n"sv; constexpr auto TOKEN_LINUX_FILENAME_ARG = "{{LINUX_FILENAME_ARG}}"sv; constexpr auto TOKEN_WINDOWS_FILENAME_ARG = "{{WINDOWS_FILENAME_ARG}}"sv; constexpr auto TOKEN_LINUX_ARGS = "{{LINUX_ARGS}}"sv; constexpr auto TOKEN_WINDOWS_ARGS = "{{WINDOWS_ARGS}}"sv; constexpr auto TOKEN_LINUX_ARGS_COMBINED = "{{LINUX_ARGS_COMBINED}}"sv; constexpr auto TOKEN_WINDOWS_ARGS_COMBINED = "{{WINDOWS_ARGS_COMBINED}}"sv; #define LINUX_EXTRACT_ITEM R"(ITEM={{LINUX_FILENAME_ARG}};SELF=$(basename -- "$0");DIR="pdvzip_$$";clear;mkdir "$DIR"||exit;mv -- "$0" "$DIR"||exit;cd "$DIR"||exit;unzip -qo -- "$SELF"||exit;)" #define LINUX_EXTRACT_ITEM_HASH R"(ITEM={{LINUX_FILENAME_ARG}};SELF=$(basename -- "$0");DIR="pdvzip_$$";clear;mkdir "$DIR"||exit;mv -- "$0" "$DIR"||exit;cd "$DIR"||exit;unzip -qo -- "$SELF"||exit;hash -r;)" #define LINUX_EXTRACT_ITEM_HASH_NULL R"(ITEM={{LINUX_FILENAME_ARG}};SELF=$(basename -- "$0");DIR="pdvzip_$$";NUL="/dev/null";clear;mkdir "$DIR"||exit;mv -- "$0" "$DIR"||exit;cd "$DIR"||exit;unzip -qo -- "$SELF"||exit;hash -r;)" #define LINUX_EXTRACT_NO_ITEM R"(SELF=$(basename -- "$0");DIR="pdvzip_$$";clear;mkdir "$DIR"||exit;mv -- "$0" "$DIR"||exit;cd "$DIR"||exit;unzip -qo -- "$SELF"||exit;)" #define WINDOWS_EXTRACT R"(#&cls&setlocal EnableDelayedExpansion&set "DIR=pdvzip_!RANDOM!"&mkdir ".\!DIR!"||exit /b&move "%~dpnx0" ".\!DIR!"||exit /b&cd ".\!DIR!"||exit /b&cls&tar -xf "%~n0%~x0"||exit /b&ren "%~n0%~x0" *.png&)" #define WINDOWS_PYTHON_EXTRACT R"(#&cls&setlocal EnableDelayedExpansion&set "APP=python3"&set "DIR=pdvzip_!RANDOM!"&mkdir ".\!DIR!"||exit /b&move "%~dpnx0" ".\!DIR!"||exit /b&cd ".\!DIR!"||exit /b&cls&tar -xf "%~n0%~x0"||exit /b&ren "%~n0%~x0" *.png&)" #define WINDOWS_POWERSHELL_EXTRACT R"(#&cls&setlocal EnableDelayedExpansion&set "PDIR=%SystemDrive%\Program Files\PowerShell\"&set "DIR=pdvzip_!RANDOM!"&mkdir ".\!DIR!"||exit /b&move "%~dpnx0" ".\!DIR!"||exit /b&cd ".\!DIR!"||exit /b&cls&tar -xf "%~n0%~x0"||exit /b&ren "%~n0%~x0" *.png&)" struct ScriptTemplate { std::string_view linux_part; std::string_view windows_part; }; struct PlaceholderReplacement { std::string_view token; std::string value; }; [[nodiscard]] ScriptTemplate getScriptTemplate(FileType file_type) { switch (file_type) { case FileType::VIDEO_AUDIO: return { std::string_view(LINUX_EXTRACT_ITEM_HASH_NULL R"(if command -v mpv >$NUL 2>&1;then clear;mpv --quiet --geometry=50%:50% "$ITEM" &> $NUL;elif command -v vlc >$NUL 2>&1;then clear;vlc --play-and-exit --no-video-title-show "$ITEM" &> $NUL;elif command -v firefox >$NUL 2>&1;then clear;firefox "$ITEM" &> $NUL;else clear;fi;exit;)"), std::string_view(WINDOWS_EXTRACT R"(start "" {{WINDOWS_FILENAME_ARG}}&exit)") }; case FileType::PDF: return { std::string_view(LINUX_EXTRACT_ITEM_HASH_NULL R"(if command -v evince >$NUL 2>&1;then clear;evince "$ITEM" &> $NUL;else firefox "$ITEM" &> $NUL;clear;fi;exit;)"), std::string_view(WINDOWS_EXTRACT R"(start "" {{WINDOWS_FILENAME_ARG}}&exit)") }; case FileType::PYTHON: return { std::string_view(LINUX_EXTRACT_ITEM_HASH R"(if command -v python3 >/dev/null 2>&1;then clear;python3 "$ITEM" {{LINUX_ARGS}};else clear;fi;exit;)"), std::string_view(WINDOWS_PYTHON_EXTRACT R"(where "!APP!" >nul 2>&1 && ("!APP!" {{WINDOWS_FILENAME_ARG}} {{WINDOWS_ARGS}} ) || (cls&exit)&echo.&exit)") }; case FileType::POWERSHELL: return { std::string_view(LINUX_EXTRACT_ITEM_HASH R"(if command -v pwsh >/dev/null 2>&1;then clear;pwsh "$ITEM" {{LINUX_ARGS}};else clear;fi;exit;)"), std::string_view(WINDOWS_POWERSHELL_EXTRACT R"(IF EXIST "!PDIR!" (pwsh -ExecutionPolicy Bypass -File {{WINDOWS_FILENAME_ARG}} {{WINDOWS_ARGS}}&echo.&exit) ELSE (powershell -ExecutionPolicy Bypass -File {{WINDOWS_FILENAME_ARG}} {{WINDOWS_ARGS}}&echo.&exit))") }; case FileType::BASH_SHELL: return { std::string_view(LINUX_EXTRACT_ITEM R"(chmod +x -- "$ITEM";"$ITEM" {{LINUX_ARGS}};exit;)"), std::string_view(WINDOWS_EXTRACT R"({{WINDOWS_FILENAME_ARG}} {{WINDOWS_ARGS}}&cls&exit)") }; case FileType::WINDOWS_EXECUTABLE: return { std::string_view(LINUX_EXTRACT_NO_ITEM R"(clear;exit;)"), std::string_view(WINDOWS_EXTRACT R"({{WINDOWS_FILENAME_ARG}} {{WINDOWS_ARGS_COMBINED}}&echo.&exit)") }; case FileType::FOLDER: return { std::string_view(LINUX_EXTRACT_ITEM R"(xdg-open "$ITEM" >/dev/null 2>&1;clear;exit;)"), std::string_view(WINDOWS_EXTRACT R"(start "" {{WINDOWS_FILENAME_ARG}}&cls&exit)") }; case FileType::LINUX_EXECUTABLE: return { std::string_view(LINUX_EXTRACT_ITEM R"(chmod +x -- "$ITEM";"$ITEM" {{LINUX_ARGS_COMBINED}};exit;)"), std::string_view(WINDOWS_EXTRACT R"(cls&exit)") }; case FileType::JAR: return { R"(clear;hash -r;if command -v java >/dev/null 2>&1;then clear;java -jar "$0" {{LINUX_ARGS}};else clear;fi;exit;)"sv, R"(#&cls&setlocal EnableDelayedExpansion&set "APP=java"&cls&where "!APP!" >nul 2>&1 && ("!APP!" -jar "%~dpnx0" {{WINDOWS_ARGS}} ) || (cls)&ren "%~dpnx0" *.png&echo.&exit)"sv }; case FileType::UNKNOWN_FILE_TYPE: default: return { std::string_view(LINUX_EXTRACT_ITEM R"(xdg-open "$ITEM" >/dev/null 2>&1;exit;)"), std::string_view(WINDOWS_EXTRACT R"(start "" {{WINDOWS_FILENAME_ARG}}&echo.&exit)") }; } } #undef LINUX_EXTRACT_ITEM #undef LINUX_EXTRACT_ITEM_HASH #undef LINUX_EXTRACT_ITEM_HASH_NULL #undef LINUX_EXTRACT_NO_ITEM #undef WINDOWS_EXTRACT #undef WINDOWS_PYTHON_EXTRACT #undef WINDOWS_POWERSHELL_EXTRACT void validateScriptInput(std::string_view value, std::string_view field_name) { const bool has_control_char = std::ranges::any_of(value, [](unsigned char c) { return std::iscntrl(c) != 0; }); if (has_control_char) { throw std::runtime_error(std::format( "Arguments Error: {} contains unsupported control characters.", field_name)); } } std::vector splitPosixArguments(std::string_view input, std::string_view field_name) { enum class QuoteState : Byte { none, single, double_quote }; auto syntaxError = [&](std::string_view reason) { throw std::runtime_error(std::format( "Arguments Error: {} {}", field_name, reason)); }; std::vector args; std::string current; QuoteState state = QuoteState::none; bool escaped = false; bool token_started = false; for (char ch : input) { if (state == QuoteState::single) { if (ch == '\'') { state = QuoteState::none; } else { current.push_back(ch); } token_started = true; continue; } if (escaped) { current.push_back(ch); escaped = false; token_started = true; continue; } if (state == QuoteState::double_quote) { if (ch == '"') { state = QuoteState::none; } else if (ch == '\\') { escaped = true; } else { current.push_back(ch); } token_started = true; continue; } if (std::isspace(static_cast(ch))) { if (token_started) { args.push_back(current); current.clear(); token_started = false; } continue; } switch (ch) { case '\\': escaped = true; token_started = true; break; case '\'': state = QuoteState::single; token_started = true; break; case '"': state = QuoteState::double_quote; token_started = true; break; default: current.push_back(ch); token_started = true; break; } } if (escaped) { syntaxError("end with an unfinished escape sequence."); } if (state != QuoteState::none) { syntaxError("contain unmatched quotes."); } if (token_started) { args.push_back(current); } return args; } std::vector splitWindowsArguments(std::string_view input, std::string_view field_name) { auto syntaxError = [&](std::string_view reason) { throw std::runtime_error(std::format( "Arguments Error: {} {}", field_name, reason)); }; std::vector args; std::size_t i = 0; while (i < input.size()) { while (i < input.size() && std::isspace(static_cast(input[i]))) { ++i; } if (i >= input.size()) { break; } std::string current; bool in_quotes = false; std::size_t backslashes = 0; while (i < input.size()) { const char ch = input[i]; if (ch == '\\') { ++backslashes; ++i; continue; } if (ch == '"') { if ((backslashes % 2) == 0) { current.append(backslashes / 2, '\\'); backslashes = 0; if (in_quotes && (i + 1) < input.size() && input[i + 1] == '"') { current.push_back('"'); i += 2; continue; } in_quotes = !in_quotes; ++i; continue; } current.append(backslashes / 2, '\\'); current.push_back('"'); backslashes = 0; ++i; continue; } if (backslashes > 0) { current.append(backslashes, '\\'); backslashes = 0; } if (!in_quotes && std::isspace(static_cast(ch))) { break; } current.push_back(ch); ++i; } if (backslashes > 0) { current.append(backslashes, '\\'); } if (in_quotes) { syntaxError("contain unmatched double quotes."); } args.push_back(std::move(current)); while (i < input.size() && std::isspace(static_cast(input[i]))) { ++i; } } return args; } std::string quotePosixArgument(std::string_view arg) { std::string out; out.reserve(arg.size() + 2); out.push_back('\''); for (char ch : arg) { if (ch == '\'') { out.append("'\\''"); } else { out.push_back(ch); } } out.push_back('\''); return out; } std::string quoteWindowsArgumentForCmd(std::string_view arg) { std::string out; out.reserve(arg.size() * 2 + 2); out.push_back('"'); std::size_t backslashes = 0; for (char ch : arg) { if (ch == '\\') { ++backslashes; continue; } if (ch == '"') { out.append(backslashes * 2 + 1, '\\'); out.push_back('"'); backslashes = 0; continue; } if (backslashes > 0) { out.append(backslashes, '\\'); backslashes = 0; } // Prevent percent-expansion in CMD (including inside quoted args). if (ch == '%') { out.append("%%"); } else if (ch == '!') { // Inside double quotes with delayed expansion enabled, // '!' cannot be escaped by any means. Break out of the // quoted region, emit ^! (literal '!' outside quotes), // then immediately reopen the quoted region. out.append("\"^!\""); } else { out.push_back(ch); } } if (backslashes > 0) { out.append(backslashes * 2, '\\'); } out.push_back('"'); return out; } std::string makePosixCommandPath(std::string_view path) { if (path.empty()) { throw std::runtime_error("Script Error: Archive filename is empty."); } std::string out("./"); out.append(path); return out; } std::string makeWindowsCommandPath(std::string_view path) { if (path.empty()) { throw std::runtime_error("Script Error: Archive filename is empty."); } std::string out; out.reserve(path.size() + 2); out.append(".\\"); for (char ch : path) { out.push_back(ch == '/' ? '\\' : ch); } return out; } template std::string renderArguments(std::string_view raw_args, std::string_view field_name, SplitFn split, QuoteFn quote) { const auto args = split(raw_args, field_name); if (args.empty()) { return {}; } std::string rendered; rendered.reserve(raw_args.size() * 2 + args.size()); for (std::size_t i = 0; i < args.size(); ++i) { if (i > 0) { rendered.push_back(' '); } rendered.append(quote(args[i])); } return rendered; } std::string renderPosixArguments(std::string_view raw_args, std::string_view field_name) { return renderArguments(raw_args, field_name, splitPosixArguments, quotePosixArgument); } std::string renderWindowsArguments(std::string_view raw_args, std::string_view field_name) { return renderArguments(raw_args, field_name, splitWindowsArguments, quoteWindowsArgumentForCmd); } void ensureNoUnresolvedPlaceholders(std::string_view script_text) { constexpr auto TOKENS = std::to_array({ TOKEN_LINUX_FILENAME_ARG, TOKEN_WINDOWS_FILENAME_ARG, TOKEN_LINUX_ARGS, TOKEN_WINDOWS_ARGS, TOKEN_LINUX_ARGS_COMBINED, TOKEN_WINDOWS_ARGS_COMBINED }); for (const std::string_view token : TOKENS) { if (script_text.find(token) != std::string::npos) { throw std::runtime_error("Script Error: Unresolved placeholder token in extraction script template."); } } } void rejectTemplateDelimiters(std::string_view value, std::string_view field_name) { if (value.find("{{") != std::string::npos) { throw std::runtime_error(std::format( "Script Error: {} contains reserved template delimiter '{{}}'.", field_name)); } } std::string renderTemplate(std::string_view template_text, std::span replacements) { std::string rendered; rendered.reserve(template_text.size() + 256); std::size_t position = 0; while (position < template_text.size()) { const std::size_t marker = template_text.find("{{", position); if (marker == std::string_view::npos) { rendered.append(template_text.substr(position)); break; } rendered.append(template_text.substr(position, marker - position)); bool matched = false; for (const PlaceholderReplacement& replacement : replacements) { if (template_text.substr(marker, replacement.token.size()) == replacement.token) { rendered.append(replacement.value); position = marker + replacement.token.size(); matched = true; break; } } if (!matched) { rendered.append("{{"); position = marker + 2; } } return rendered; } void validateScriptInputs(const std::string& first_filename, const UserArguments& user_args) { validateScriptInput(first_filename, "Archive filename"); validateScriptInput(user_args.linux_args, "Linux arguments"); validateScriptInput(user_args.windows_args, "Windows arguments"); // Reject values that contain template token delimiters, so user input cannot // impersonate a placeholder while the template is rendered. rejectTemplateDelimiters(first_filename, "Archive filename"); rejectTemplateDelimiters(user_args.linux_args, "Linux arguments"); rejectTemplateDelimiters(user_args.windows_args, "Windows arguments"); } [[nodiscard]] std::string_view combinedArgumentsRaw(const UserArguments& user_args) { return user_args.linux_args.empty() ? std::string_view(user_args.windows_args) : std::string_view(user_args.linux_args); } [[nodiscard]] std::array makePlaceholderReplacements( const std::string& first_filename, const UserArguments& user_args ) { const std::string_view args_combined_raw = combinedArgumentsRaw(user_args); return std::array{{ { TOKEN_LINUX_FILENAME_ARG, quotePosixArgument(makePosixCommandPath(first_filename)) }, { TOKEN_WINDOWS_FILENAME_ARG, quoteWindowsArgumentForCmd(makeWindowsCommandPath(first_filename)) }, { TOKEN_LINUX_ARGS, renderPosixArguments(user_args.linux_args, "Linux arguments") }, { TOKEN_WINDOWS_ARGS, renderWindowsArguments(user_args.windows_args, "Windows arguments") }, { TOKEN_LINUX_ARGS_COMBINED, renderPosixArguments(args_combined_raw, "Combined Linux arguments") }, { TOKEN_WINDOWS_ARGS_COMBINED, renderWindowsArguments(args_combined_raw, "Combined Windows arguments") }, }}; } [[nodiscard]] std::string joinScriptTemplate(const ScriptTemplate& script_template) { std::string template_text; template_text.reserve(script_template.linux_part.size() + CRLF.size() + script_template.windows_part.size()); template_text.append(script_template.linux_part); template_text.append(CRLF); template_text.append(script_template.windows_part); return template_text; } } // namespace namespace script_builder_internal { std::string buildScriptText( FileType file_type, const std::string& first_filename, const UserArguments& user_args) { validateScriptInputs(first_filename, user_args); const ScriptTemplate script_template = getScriptTemplate(file_type); const std::array replacements = makePlaceholderReplacements(first_filename, user_args); const std::string template_text = joinScriptTemplate(script_template); std::string script_text = renderTemplate(template_text, replacements); ensureNoUnresolvedPlaceholders(script_text); return script_text; } } // namespace script_builder_internal ================================================ FILE: src/user_input.cpp ================================================ #include "pdvzip.h" namespace { constexpr std::size_t MAX_ARG_LENGTH = 1024; [[nodiscard]] bool fileTypeAcceptsArguments(FileType file_type) { return (file_type > FileType::PDF && file_type < FileType::UNKNOWN_FILE_TYPE) || file_type == FileType::LINUX_EXECUTABLE || file_type == FileType::JAR; } void readArgumentLine(std::string& out, std::string_view label) { out.clear(); out.reserve(MAX_ARG_LENGTH); while (out.size() < MAX_ARG_LENGTH) { const int ch = std::cin.get(); if (ch == std::char_traits::eof()) { if (std::cin.bad()) { throw std::runtime_error(std::format( "Input Error: Failed to read {} (stdin closed or unreadable).", label)); } return; } if (ch == '\n') { return; } out.push_back(static_cast(ch)); } // We've read MAX_ARG_LENGTH characters without seeing a newline. // If the next character is a newline or EOF, the line is exactly at the cap. const int next = std::cin.peek(); if (next == std::char_traits::eof() || next == '\n') { if (next == '\n') { std::cin.get(); } return; } throw std::runtime_error(std::format( "Input Error: {} exceed maximum length of {} bytes.", label, MAX_ARG_LENGTH)); } } // anonymous namespace UserArguments promptForArguments(FileType file_type) { UserArguments args; if (!fileTypeAcceptsArguments(file_type)) { return args; } std::println("\nFor this file type, if required, you can provide command-line arguments here."); if (file_type != FileType::WINDOWS_EXECUTABLE) { std::print("\nLinux: "); readArgumentLine(args.linux_args, "Linux arguments"); } if (file_type != FileType::LINUX_EXECUTABLE) { std::print("\nWindows: "); readArgumentLine(args.windows_args, "Windows arguments"); } return args; }