f2372fba3b
Reasoning: In `HuffmanTablesSegment` (`src/utils/huffman_utils.h`), `start` was annotated `WEBP_COUNTED_BY_OR_NULL(size)` as it points to an allocation of `size` elements. `curr_table` was annotated `WEBP_UNSAFE_INDEXABLE` because it iterates within `[start, start + size)`, a bound that cannot be expressed statically in the struct without ABI changes. The code manually checks bounds for `curr_table` (e.g., `src/utils/huffman_utils.c:240-241`). To support the annotation on `start`, allocation sites in `VP8LBuildHuffmanTable` and `VP8LHuffmanTablesAllocate` (`src/utils/huffman_utils.c`) were refactored to assign `start` and `size` side-by-side, using `WEBP_BIDI_INDEXABLE` local variables to hold the safe pointer returned by `WebPSafeMalloc`. `VP8LHuffmanTablesDeallocate` was updated to set `size` to 0 when `start` is freed. The `root_table` parameter of `BuildHuffmanTable` (`src/utils/huffman_utils.c:86`) was annotated `WEBP_BIDI_INDEXABLE` to accommodate accesses to secondary tables beyond the `root table` size since with explicitly annotating the local variable `table` as `WEBP_BIDI_INDEXABLE`, `table` inherits its bounds from `root_table`. Call sites in `VP8LBuildHuffmanTable` required `WEBP_UNSAFE_FORGE_BIDI_INDEXABLE` to convert the unsafe `curr_table` to the safe `root_table`. The `table` parameter of `ReplicateValue` (`src/utils/huffman_utils.c:59`) was annotated `WEBP_COUNTED_BY(end - step + 1)` and the function was refactored to avoid modifying `end`. Call sites in `BuildHuffmanTable` required `WEBP_UNSAFE_FORGE_BIDI_INDEXABLE` because the strided access patterns used for Huffman table construction cannot be statically verified by the compiler. Bug: 432511821 Change-Id: I77c5c82ac36bc9bb79cd5119a4113ac5d62af762
WebP Codec
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WebP codec is a library to encode and decode images in WebP format. This package contains the library that can be used in other programs to add WebP support, as well as the command line tools 'cwebp' and 'dwebp' to compress and decompress images respectively.
See https://developers.google.com/speed/webp for details on the image format.
The latest source tree is available at https://chromium.googlesource.com/webm/libwebp
It is released under the same license as the WebM project. See https://www.webmproject.org/license/software/ or the "COPYING" file for details. An additional intellectual property rights grant can be found in the file PATENTS.
Building
See the building documentation.
Encoding and Decoding Tools
The examples/ directory contains tools to encode and decode images and animations, view information about WebP images, and more. See the tools documentation.
APIs
See the APIs documentation, and API usage examples in the
examples/ directory.
Bugs
Please report all bugs to the issue tracker. For security reports, select 'Security report' from the Template dropdown.
Patches welcome! See how to contribute.
Discuss
Email: webp-discuss@webmproject.org
Web: https://groups.google.com/a/webmproject.org/group/webp-discuss