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1/*2 * Copyright (c) Yann Collet, Facebook, Inc.3 * All rights reserved.4 *5 * This source code is licensed under both the BSD-style license (found in the6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found7 * in the COPYING file in the root directory of this source tree).8 * You may select, at your option, one of the above-listed licenses.9 */10 11#ifndef ZSTD_LDM_H12#define ZSTD_LDM_H13 14 15#include "zstd_compress_internal.h" /* ldmParams_t, U32 */16#include <linux/zstd.h> /* ZSTD_CCtx, size_t */17 18/*-*************************************19* Long distance matching20***************************************/21 22#define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_LIMIT_DEFAULT23 24void ZSTD_ldm_fillHashTable(25 ldmState_t* state, const BYTE* ip,26 const BYTE* iend, ldmParams_t const* params);27 28/*29 * ZSTD_ldm_generateSequences():30 *31 * Generates the sequences using the long distance match finder.32 * Generates long range matching sequences in `sequences`, which parse a prefix33 * of the source. `sequences` must be large enough to store every sequence,34 * which can be checked with `ZSTD_ldm_getMaxNbSeq()`.35 * @returns 0 or an error code.36 *37 * NOTE: The user must have called ZSTD_window_update() for all of the input38 * they have, even if they pass it to ZSTD_ldm_generateSequences() in chunks.39 * NOTE: This function returns an error if it runs out of space to store40 * sequences.41 */42size_t ZSTD_ldm_generateSequences(43 ldmState_t* ldms, rawSeqStore_t* sequences,44 ldmParams_t const* params, void const* src, size_t srcSize);45 46/*47 * ZSTD_ldm_blockCompress():48 *49 * Compresses a block using the predefined sequences, along with a secondary50 * block compressor. The literals section of every sequence is passed to the51 * secondary block compressor, and those sequences are interspersed with the52 * predefined sequences. Returns the length of the last literals.53 * Updates `rawSeqStore.pos` to indicate how many sequences have been consumed.54 * `rawSeqStore.seq` may also be updated to split the last sequence between two55 * blocks.56 * @return The length of the last literals.57 *58 * NOTE: The source must be at most the maximum block size, but the predefined59 * sequences can be any size, and may be longer than the block. In the case that60 * they are longer than the block, the last sequences may need to be split into61 * two. We handle that case correctly, and update `rawSeqStore` appropriately.62 * NOTE: This function does not return any errors.63 */64size_t ZSTD_ldm_blockCompress(rawSeqStore_t* rawSeqStore,65 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],66 ZSTD_paramSwitch_e useRowMatchFinder,67 void const* src, size_t srcSize);68 69/*70 * ZSTD_ldm_skipSequences():71 *72 * Skip past `srcSize` bytes worth of sequences in `rawSeqStore`.73 * Avoids emitting matches less than `minMatch` bytes.74 * Must be called for data that is not passed to ZSTD_ldm_blockCompress().75 */76void ZSTD_ldm_skipSequences(rawSeqStore_t* rawSeqStore, size_t srcSize,77 U32 const minMatch);78 79/* ZSTD_ldm_skipRawSeqStoreBytes():80 * Moves forward in rawSeqStore by nbBytes, updating fields 'pos' and 'posInSequence'.81 * Not to be used in conjunction with ZSTD_ldm_skipSequences().82 * Must be called for data with is not passed to ZSTD_ldm_blockCompress().83 */84void ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes);85 86/* ZSTD_ldm_getTableSize() :87 * Estimate the space needed for long distance matching tables or 0 if LDM is88 * disabled.89 */90size_t ZSTD_ldm_getTableSize(ldmParams_t params);91 92/* ZSTD_ldm_getSeqSpace() :93 * Return an upper bound on the number of sequences that can be produced by94 * the long distance matcher, or 0 if LDM is disabled.95 */96size_t ZSTD_ldm_getMaxNbSeq(ldmParams_t params, size_t maxChunkSize);97 98/* ZSTD_ldm_adjustParameters() :99 * If the params->hashRateLog is not set, set it to its default value based on100 * windowLog and params->hashLog.101 *102 * Ensures that params->bucketSizeLog is <= params->hashLog (setting it to103 * params->hashLog if it is not).104 *105 * Ensures that the minMatchLength >= targetLength during optimal parsing.106 */107void ZSTD_ldm_adjustParameters(ldmParams_t* params,108 ZSTD_compressionParameters const* cParams);109 110 111#endif /* ZSTD_FAST_H */112