| /* |
| * Copyright (c) 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). |
| * You may select, at your option, one of the above-listed licenses. |
| */ |
| |
| #ifndef ZSTD_LDM_H |
| #define ZSTD_LDM_H |
| |
| |
| #include "zstd_compress_internal.h" /* ldmParams_t, U32 */ |
| #include <linux/zstd.h> /* ZSTD_CCtx, size_t */ |
| |
| /*-************************************* |
| * Long distance matching |
| ***************************************/ |
| |
| #define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_LIMIT_DEFAULT |
| |
| void ZSTD_ldm_fillHashTable( |
| ldmState_t* state, const BYTE* ip, |
| const BYTE* iend, ldmParams_t const* params); |
| |
| /* |
| * 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], |
| void const* src, size_t srcSize); |
| |
| /* |
| * ZSTD_ldm_skipSequences(): |
| * |
| * Skip past `srcSize` bytes worth of sequences in `rawSeqStore`. |
| * Avoids emitting matches less than `minMatch` bytes. |
| * Must be called for data that is not passed to ZSTD_ldm_blockCompress(). |
| */ |
| void ZSTD_ldm_skipSequences(rawSeqStore_t* rawSeqStore, size_t srcSize, |
| U32 const minMatch); |
| |
| /* ZSTD_ldm_skipRawSeqStoreBytes(): |
| * Moves forward in rawSeqStore by nbBytes, updating fields 'pos' and 'posInSequence'. |
| * Not to be used in conjunction with ZSTD_ldm_skipSequences(). |
| * Must be called for data with is not passed to ZSTD_ldm_blockCompress(). |
| */ |
| void ZSTD_ldm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes); |
| |
| /* 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_adjustParameters() : |
| * If the params->hashRateLog 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); |
| |
| |
| #endif /* ZSTD_FAST_H */ |