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ZSTD_initCStream() optimization : do not allocate a CDict when no dictionary used

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This commit is contained in:
Yann Collet 2016-10-27 14:20:55 -07:00
parent bfae317ae3
commit ee5b725823
2 changed files with 20 additions and 13 deletions
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31
lib/compress/zstd_compress.c
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@ -2489,13 +2489,13 @@ static size_t ZSTD_checkDictNCount(short* normalizedCounter, unsigned dictMaxSym
/* Dictionary format :
Magic == ZSTD_DICT_MAGIC (4 bytes)
HUF_writeCTable(256)
FSE_writeNCount(off)
FSE_writeNCount(ml)
FSE_writeNCount(ll)
RepOffsets
Dictionary content
Magic == ZSTD_DICT_MAGIC (4 bytes)
HUF_writeCTable(256)
FSE_writeNCount(off)
FSE_writeNCount(ml)
FSE_writeNCount(ll)
RepOffsets
Dictionary content
*/
/*! ZSTD_loadDictEntropyStats() :
@return : size read from dictionary
@ -2839,6 +2839,7 @@ struct ZSTD_CStream_s {
ZSTD_cStreamStage stage;
U32 checksum;
U32 frameEnded;
ZSTD_parameters params;
ZSTD_customMem customMem;
}; /* typedef'd to ZSTD_CStream within "zstd.h" */
@ -2884,7 +2885,10 @@ size_t ZSTD_CStreamOutSize(void) { return ZSTD_compressBound(ZSTD_BLOCKSIZE_ABSO
size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize)
{
CHECK_F(ZSTD_compressBegin_usingCDict(zcs->cctx, zcs->cdict, pledgedSrcSize));
if (zcs->inBuffSize==0) return ERROR(stage_wrong); /* zcs has not been init at least once */
if (zcs->cdict) CHECK_F(ZSTD_compressBegin_usingCDict(zcs->cctx, zcs->cdict, pledgedSrcSize))
else CHECK_F(ZSTD_compressBegin_advanced(zcs->cctx, NULL, 0, zcs->params, pledgedSrcSize));
zcs->inToCompress = 0;
zcs->inBuffPos = 0;
@ -2916,12 +2920,15 @@ size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
if (zcs->outBuff == NULL) return ERROR(memory_allocation);
}
ZSTD_freeCDict(zcs->cdictLocal);
zcs->cdictLocal = ZSTD_createCDict_advanced(dict, dictSize, params, zcs->customMem);
if (zcs->cdictLocal == NULL) return ERROR(memory_allocation);
zcs->cdict = zcs->cdictLocal;
if (dict) {
ZSTD_freeCDict(zcs->cdictLocal);
zcs->cdictLocal = ZSTD_createCDict_advanced(dict, dictSize, params, zcs->customMem);
if (zcs->cdictLocal == NULL) return ERROR(memory_allocation);
zcs->cdict = zcs->cdictLocal;
} else zcs->cdict = NULL;
zcs->checksum = params.fParams.checksumFlag > 0;
zcs->params = params;
return ZSTD_resetCStream(zcs, pledgedSrcSize);
}

2
lib/zstd.h
View File

@ -460,7 +460,7 @@ ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dic
ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize is optional and can be zero == unknown */
ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); /**< note : cdict will just be referenced, and must outlive compression session */
ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); /**< re-use compression parameters from previous init; saves dictionary loading */
ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); /**< re-use compression parameters from previous init; skip dictionary loading stage; zcs must be init at least once before */
ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);