Mercurial > hg
view contrib/python-zstandard/zstd/compress/zstd_ldm.h @ 37495:b1fb341d8a61
zstandard: vendor python-zstandard 0.9.0
This was just released. It features a number of goodies. More info at
https://gregoryszorc.com/blog/2018/04/09/release-of-python-zstandard-0.9/.
The clang-format ignore list was updated to reflect the new source
of files.
The project contains a vendored copy of zstandard 1.3.4. The old
version was 1.1.3. One of the changes between those versions is that
zstandard is now dual licensed BSD + GPLv2 and the patent rights grant
has been removed. Good riddance.
The API should be backwards compatible. So no changes in core
should be needed. However, there were a number of changes in the
library that we'll want to adapt to. Those will be addressed in
subsequent commits.
Differential Revision: https://phab.mercurial-scm.org/D3198
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Mon, 09 Apr 2018 10:13:29 -0700 |
parents | |
children | 73fef626dae3 |
line wrap: on
line source
/* * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the * LICENSE file in the root directory of this source tree) and the GPLv2 (found * in the COPYING file in the root directory of this source tree). */ #ifndef ZSTD_LDM_H #define ZSTD_LDM_H #if defined (__cplusplus) extern "C" { #endif #include "zstd_compress_internal.h" /* ldmParams_t, U32 */ #include "zstd.h" /* ZSTD_CCtx, size_t */ /*-************************************* * Long distance matching ***************************************/ #define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_DEFAULTMAX /** * ZSTD_ldm_generateSequences(): * * Generates the sequences using the long distance match finder. * Generates long range matching sequences in `sequences`, which parse a prefix * of the source. `sequences` must be large enough to store every sequence, * which can be checked with `ZSTD_ldm_getMaxNbSeq()`. * @returns 0 or an error code. * * NOTE: The user must have called ZSTD_window_update() for all of the input * they have, even if they pass it to ZSTD_ldm_generateSequences() in chunks. * NOTE: This function returns an error if it runs out of space to store * sequences. */ size_t ZSTD_ldm_generateSequences( ldmState_t* ldms, rawSeqStore_t* sequences, ldmParams_t const* params, void const* src, size_t srcSize); /** * ZSTD_ldm_blockCompress(): * * Compresses a block using the predefined sequences, along with a secondary * block compressor. The literals section of every sequence is passed to the * secondary block compressor, and those sequences are interspersed with the * predefined sequences. Returns the length of the last literals. * Updates `rawSeqStore.pos` to indicate how many sequences have been consumed. * `rawSeqStore.seq` may also be updated to split the last sequence between two * blocks. * @return The length of the last literals. * * NOTE: The source must be at most the maximum block size, but the predefined * sequences can be any size, and may be longer than the block. In the case that * they are longer than the block, the last sequences may need to be split into * two. We handle that case correctly, and update `rawSeqStore` appropriately. * NOTE: This function does not return any errors. */ size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore, ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize, int const extDict); /** * ZSTD_ldm_skipSequences(): * * Skip past `srcSize` bytes worth of sequences in `rawSeqStore`. * Avoids emitting matches less than `minMatch` bytes. * Must be called for data with is not passed to ZSTD_ldm_blockCompress(). */ void ZSTD_ldm_skipSequences(rawSeqStore_t* rawSeqStore, size_t srcSize, U32 const minMatch); /** ZSTD_ldm_getTableSize() : * Estimate the space needed for long distance matching tables or 0 if LDM is * disabled. */ size_t ZSTD_ldm_getTableSize(ldmParams_t params); /** ZSTD_ldm_getSeqSpace() : * Return an upper bound on the number of sequences that can be produced by * the long distance matcher, or 0 if LDM is disabled. */ size_t ZSTD_ldm_getMaxNbSeq(ldmParams_t params, size_t maxChunkSize); /** ZSTD_ldm_getTableSize() : * Return prime8bytes^(minMatchLength-1) */ U64 ZSTD_ldm_getHashPower(U32 minMatchLength); /** ZSTD_ldm_adjustParameters() : * If the params->hashEveryLog is not set, set it to its default value based on * windowLog and params->hashLog. * * Ensures that params->bucketSizeLog is <= params->hashLog (setting it to * params->hashLog if it is not). * * Ensures that the minMatchLength >= targetLength during optimal parsing. */ void ZSTD_ldm_adjustParameters(ldmParams_t* params, ZSTD_compressionParameters const* cParams); #if defined (__cplusplus) } #endif #endif /* ZSTD_FAST_H */