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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
commit | 19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch) | |
tree | 42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/zstd/doc/educational_decoder/README.md | |
parent | Initial commit. (diff) | |
download | ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.tar.xz ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.zip |
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/zstd/doc/educational_decoder/README.md')
-rw-r--r-- | src/zstd/doc/educational_decoder/README.md | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/zstd/doc/educational_decoder/README.md b/src/zstd/doc/educational_decoder/README.md new file mode 100644 index 000000000..c89451ca0 --- /dev/null +++ b/src/zstd/doc/educational_decoder/README.md @@ -0,0 +1,36 @@ +Educational Decoder +=================== + +`zstd_decompress.c` is a self-contained implementation in C99 of a decoder, +according to the [Zstandard format specification]. +While it does not implement as many features as the reference decoder, +such as the streaming API or content checksums, it is written to be easy to +follow and understand, to help understand how the Zstandard format works. +It's laid out to match the [format specification], +so it can be used to understand how complex segments could be implemented. +It also contains implementations of Huffman and FSE table decoding. + +[Zstandard format specification]: https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md +[format specification]: https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md + +While the library's primary objective is code clarity, +it also happens to compile into a small object file. +The object file can be made even smaller by removing error messages, +using the macro directive `ZDEC_NO_MESSAGE` at compilation time. +This can be reduced even further by foregoing dictionary support, +by defining `ZDEC_NO_DICTIONARY`. + +`harness.c` provides a simple test harness around the decoder: + + harness <input-file> <output-file> [dictionary] + +As an additional resource to be used with this decoder, +see the `decodecorpus` tool in the [tests] directory. +It generates valid Zstandard frames that can be used to verify +a Zstandard decoder implementation. +Note that to use the tool to verify this decoder implementation, +the --content-size flag should be set, +as this decoder does not handle streaming decoding, +and so it must know the decompressed size in advance. + +[tests]: https://github.com/facebook/zstd/blob/dev/tests/ |