Integrate build system support for the Zstandard (zstd) library and implement the corresponding C++ decompression stream classes, enabling future use of zstd-compressed streams in ZIP packages. Build System (Part 2a): - Add `--with-system-zstd=[yes|no|auto]` configure option. - Implement system library checks (`zstd.h`, `libzstd`) in configure.ac. - Define rules (`external/zstd/*`) for downloading and building the internal zstd static library (decompression components only). - Set up necessary CFLAGS/LIBS via configure.ac and config_host.mk.in. - Configure linking via RepositoryExternal.mk (`gb_LinkTarget__use_zstd`). - Update auxiliary files (download.lst, distro-configs, etc.). C++ Implementation (Part 2b): - Implement `InflateZstd` (in `include/package`) and `InflaterBytesZstd` (in `package/inc`) inheriting from `Inflater`/`InflaterBytes`. - Use the zstd streaming API (`ZSTD_decompressStream`) following the existing single-call pattern established by the zlib implementation. - Manage context (`ZSTD_DCtx`) and input buffer (`ZSTD_inBuffer`) state. - Handle errors, stream completion (`ret == 0`), and input truncation. - Add new classes to `package/Library_package2.mk` build. This completes the infrastructure for zstd decompression support. The next step (Part 2c) involves adding logic to select the appropriate Inflater based on the ZIP entry's compression method ID. Change-Id: Ia673f3f19b6a751ba5225394fcf8c3f145c4ae63 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/184243 Tested-by: Jenkins Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>
ZIP Support
Reading and writing ZIP files.