1 Educational Decoder 2 =================== 3 4 `zstd_decompress.c` is a self-contained implementation in C99 of a decoder, 5 according to the [Zstandard format specification]. 6 While it does not implement as many features as the reference decoder, 7 such as the streaming API or content checksums, it is written to be easy to 8 follow and understand, to help understand how the Zstandard format works. 9 It's laid out to match the [format specification], 10 so it can be used to understand how complex segments could be implemented. 11 It also contains implementations of Huffman and FSE table decoding. 12 13 [Zstandard format specification]: https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md 14 [format specification]: https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md 15 16 While the library's primary objective is code clarity, 17 it also happens to compile into a small object file. 18 The object file can be made even smaller by removing error messages, 19 using the macro directive `ZDEC_NO_MESSAGE` at compilation time. 20 This can be reduced even further by foregoing dictionary support, 21 by defining `ZDEC_NO_DICTIONARY`. 22 23 `harness.c` provides a simple test harness around the decoder: 24 25 harness <input-file> <output-file> [dictionary] 26 27 As an additional resource to be used with this decoder, 28 see the `decodecorpus` tool in the [tests] directory. 29 It generates valid Zstandard frames that can be used to verify 30 a Zstandard decoder implementation. 31 Note that to use the tool to verify this decoder implementation, 32 the --content-size flag should be set, 33 as this decoder does not handle streaming decoding, 34 and so it must know the decompressed size in advance. 35 36 [tests]: https://github.com/facebook/zstd/blob/dev/tests/ 37
Indexes created Mon Jun 01 00:24:59 UTC 2026