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Added multiplier, renamed new enum to something more useful

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This commit is contained in:
Sen Huang 2019-10-21 15:29:55 -04:00
parent 1f3a51fb52
commit 676f89902a
2 changed files with 16 additions and 9 deletions
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17
lib/compress/zstd_compress.c
View File

@ -387,7 +387,7 @@ ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter param)
case ZSTD_c_forceAttachDict:
ZSTD_STATIC_ASSERT(ZSTD_dictDefaultAttach < ZSTD_dictForceCopy);
bounds.lowerBound = ZSTD_dictDefaultAttach;
bounds.upperBound = ZSTD_dictForceSource; /* note : how to ensure at compile time that this is the highest value enum ? */
bounds.upperBound = ZSTD_dictForceLoad; /* note : how to ensure at compile time that this is the highest value enum ? */
return bounds;
case ZSTD_c_literalCompressionMode:
@ -2890,7 +2890,8 @@ ZSTD_compress_insertDictionary(ZSTD_compressedBlockState_t* bs,
bs, ms, ws, params, dict, dictSize, dtlm, workspace);
}
#define ZSTD_USE_CDICT_PARAMS_CUTOFF (1 MB)
#define ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF (128 KB)
#define ZSTD_USE_CDICT_PARAMS_DICTSIZE_MULTIPLIER (6)
/*! ZSTD_compressBegin_internal() :
* @return : 0, or an error code */
@ -2908,8 +2909,10 @@ static size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
assert(!((dict) && (cdict))); /* either dict or cdict, not both */
if ( (cdict)
&& (cdict->dictContentSize > 0)
&& (pledgedSrcSize < ZSTD_USE_CDICT_PARAMS_CUTOFF || cdict->compressionLevel == 0)
&& (params->attachDictPref != ZSTD_dictForceSource) ) {
&& ( (pledgedSrcSize < ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF
|| pledgedSrcSize < cdict->dictContentSize * ZSTD_USE_CDICT_PARAMS_DICTSIZE_MULTIPLIER)
|| cdict->compressionLevel == 0)
&& (params->attachDictPref != ZSTD_dictForceLoad) ) {
return ZSTD_resetCCtx_usingCDict(cctx, cdict, params, pledgedSrcSize, zbuff);
}
@ -3357,8 +3360,10 @@ size_t ZSTD_compressBegin_usingCDict_advanced(
DEBUGLOG(4, "ZSTD_compressBegin_usingCDict_advanced");
RETURN_ERROR_IF(cdict==NULL, dictionary_wrong);
{ ZSTD_CCtx_params params = cctx->requestedParams;
params.cParams = ( (pledgedSrcSize < ZSTD_USE_CDICT_PARAMS_CUTOFF) || (cdict->compressionLevel == 0) )
&& (params.attachDictPref != ZSTD_dictForceSource) ?
params.cParams = ( (pledgedSrcSize < ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF
|| pledgedSrcSize < cdict->dictContentSize * ZSTD_USE_CDICT_PARAMS_DICTSIZE_MULTIPLIER)
|| (cdict->compressionLevel == 0) )
&& (params.attachDictPref != ZSTD_dictForceLoad) ?
ZSTD_getCParamsFromCDict(cdict)
: ZSTD_getCParams(cdict->compressionLevel,
pledgedSrcSize,

8
lib/zstd.h
View File

@ -1166,8 +1166,10 @@ typedef enum {
* faster than copying the CDict's tables.
*
* - The CDict's tables are not used at all, and instead we use the working
* context alone to determine how our tables are initialized. This method
* should be used when using a small dictionary to compress a large input.
* context alone to reload the dictionary and use params based on the source
* size. See ZSTD_compress_insertDictionary() and ZSTD_compress_usingDict().
* This method is effective when the dictionary sizes are very small relative
* to the input size, and the input size is fairly large to begin with.
*
* Zstd has a simple internal heuristic that selects which strategy to use
* at the beginning of a compression. However, if experimentation shows that
@ -1177,7 +1179,7 @@ typedef enum {
ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */
ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */
ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */
ZSTD_dictForceSource = 3, /* Always use src input to determine tables */
ZSTD_dictForceLoad = 3, /* Always reload the dictionary */
} ZSTD_dictAttachPref_e;
typedef enum {