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Diffstat (limited to 'src/zstd/lib/compress/zstd_ldm.h')
-rw-r--r-- | src/zstd/lib/compress/zstd_ldm.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/src/zstd/lib/compress/zstd_ldm.h b/src/zstd/lib/compress/zstd_ldm.h new file mode 100644 index 00000000..d6d3d42c --- /dev/null +++ b/src/zstd/lib/compress/zstd_ldm.h @@ -0,0 +1,67 @@ +/* + * 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 + +#include "zstd_compress.h" + +#if defined (__cplusplus) +extern "C" { +#endif + +/*-************************************* +* Long distance matching +***************************************/ + +#define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_DEFAULTMAX +#define ZSTD_LDM_HASHEVERYLOG_NOTSET 9999 + +/** ZSTD_compressBlock_ldm_generic() : + * + * This is a block compressor intended for long distance matching. + * + * The function searches for matches of length at least + * ldmParams.minMatchLength using a hash table in cctx->ldmState. + * Matches can be at a distance of up to cParams.windowLog. + * + * Upon finding a match, the unmatched literals are compressed using a + * ZSTD_blockCompressor (depending on the strategy in the compression + * parameters), which stores the matched sequences. The "long distance" + * match is then stored with the remaining literals from the + * ZSTD_blockCompressor. */ +size_t ZSTD_compressBlock_ldm(ZSTD_CCtx* cctx, const void* src, size_t srcSize); +size_t ZSTD_compressBlock_ldm_extDict(ZSTD_CCtx* ctx, + const void* src, size_t srcSize); + +/** ZSTD_ldm_initializeParameters() : + * Initialize the long distance matching parameters to their default values. */ +size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm); + +/** ZSTD_ldm_getTableSize() : + * Estimate the space needed for long distance matching tables. */ +size_t ZSTD_ldm_getTableSize(U32 hashLog, U32 bucketSizeLog); + +/** 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). */ +void ZSTD_ldm_adjustParameters(ldmParams_t* params, U32 windowLog); + +#if defined (__cplusplus) +} +#endif + +#endif /* ZSTD_FAST_H */ |