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make it possible to specify LDM parameters in any order

dev
Yann Collet 2018-03-19 11:07:04 -07:00
parent cbc71e40f6
commit 9618c0c804
4 changed files with 33 additions and 40 deletions
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12
lib/compress/zstd_compress.c
View File

@ -478,17 +478,15 @@ size_t ZSTD_CCtxParam_setParameter(
return ZSTD_ldm_initializeParameters(&CCtxParams->ldmParams, value);
case ZSTD_p_ldmHashLog :
if (value) { /* 0 : does not change current ldmHashLog */
if (value>0) /* 0 ==> auto */
CLAMPCHECK(value, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
CCtxParams->ldmParams.hashLog = value;
}
CCtxParams->ldmParams.hashLog = value;
return CCtxParams->ldmParams.hashLog;
case ZSTD_p_ldmMinMatch :
if (value) { /* 0 : does not change current ldmMinMatch */
if (value>0) /* 0 ==> default */
CLAMPCHECK(value, ZSTD_LDM_MINMATCH_MIN, ZSTD_LDM_MINMATCH_MAX);
CCtxParams->ldmParams.minMatchLength = value;
}
CCtxParams->ldmParams.minMatchLength = value;
return CCtxParams->ldmParams.minMatchLength;
case ZSTD_p_ldmBucketSizeLog :
@ -988,8 +986,6 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
zbuff, pledgedSrcSize)) {
DEBUGLOG(4, "ZSTD_equivalentParams()==1 -> continue mode (wLog1=%u, blockSize1=%u)",
zc->appliedParams.cParams.windowLog, (U32)zc->blockSize);
assert(!(params.ldmParams.enableLdm &&
params.ldmParams.hashEveryLog == ZSTD_LDM_HASHEVERYLOG_NOTSET));
return ZSTD_continueCCtx(zc, params, pledgedSrcSize);
} }
DEBUGLOG(4, "ZSTD_equivalentParams()==0 -> reset CCtx");

12
lib/compress/zstd_ldm.c
View File

@ -21,10 +21,8 @@ size_t ZSTD_ldm_initializeParameters(ldmParams_t* params, U32 enableLdm)
{
ZSTD_STATIC_ASSERT(LDM_BUCKET_SIZE_LOG <= ZSTD_LDM_BUCKETSIZELOG_MAX);
params->enableLdm = enableLdm>0;
params->hashLog = 0;
params->bucketSizeLog = LDM_BUCKET_SIZE_LOG;
params->minMatchLength = LDM_MIN_MATCH_LENGTH;
params->hashEveryLog = ZSTD_LDM_HASHEVERYLOG_NOTSET;
if (!params->bucketSizeLog) params->bucketSizeLog = LDM_BUCKET_SIZE_LOG;
if (!params->minMatchLength) params->minMatchLength = LDM_MIN_MATCH_LENGTH;
return 0;
}
@ -32,6 +30,9 @@ void ZSTD_ldm_adjustParameters(ldmParams_t* params,
ZSTD_compressionParameters const* cParams)
{
U32 const windowLog = cParams->windowLog;
DEBUGLOG(4, "ZSTD_ldm_adjustParameters");
if (!params->bucketSizeLog) params->bucketSizeLog = LDM_BUCKET_SIZE_LOG;
if (!params->minMatchLength) params->minMatchLength = LDM_MIN_MATCH_LENGTH;
if (cParams->strategy >= ZSTD_btopt) {
/* Get out of the way of the optimal parser */
U32 const minMatch = MAX(cParams->targetLength, params->minMatchLength);
@ -43,7 +44,7 @@ void ZSTD_ldm_adjustParameters(ldmParams_t* params,
params->hashLog = MAX(ZSTD_HASHLOG_MIN, windowLog - LDM_HASH_RLOG);
assert(params->hashLog <= ZSTD_HASHLOG_MAX);
}
if (params->hashEveryLog == ZSTD_LDM_HASHEVERYLOG_NOTSET) {
if (params->hashEveryLog == 0) {
params->hashEveryLog =
windowLog < params->hashLog ? 0 : windowLog - params->hashLog;
}
@ -183,6 +184,7 @@ static U64 ZSTD_ldm_ipow(U64 base, U64 exp)
}
U64 ZSTD_ldm_getHashPower(U32 minMatchLength) {
DEBUGLOG(4, "ZSTD_ldm_getHashPower: mml=%u", minMatchLength);
assert(minMatchLength >= ZSTD_LDM_MINMATCH_MIN);
return ZSTD_ldm_ipow(prime8bytes, minMatchLength - 1);
}

12
lib/compress/zstd_ldm.h
View File

@ -22,7 +22,6 @@ extern "C" {
***************************************/
#define ZSTD_LDM_DEFAULT_WINDOW_LOG ZSTD_WINDOWLOG_DEFAULTMAX
#define ZSTD_LDM_HASHEVERYLOG_NOTSET 9999
/**
* ZSTD_ldm_generateSequences():
@ -39,8 +38,8 @@ extern "C" {
* sequences.
*/
size_t ZSTD_ldm_generateSequences(
ldmState_t* ldms, rawSeqStore_t* sequences,
ldmParams_t const* params, void const* src, size_t srcSize);
ldmState_t* ldms, rawSeqStore_t* sequences,
ldmParams_t const* params, void const* src, size_t srcSize);
/**
* ZSTD_ldm_blockCompress():
@ -61,9 +60,10 @@ size_t ZSTD_ldm_generateSequences(
* 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],
ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize,
int const extDict);
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
ZSTD_compressionParameters const* cParams,
void const* src, size_t srcSize,
int const extDict);
/** ZSTD_ldm_initializeParameters() :

37
lib/zstd.h
View File

@ -991,38 +991,33 @@ typedef enum {
* Special: value 0 means "do not change strategy". */
ZSTD_p_enableLongDistanceMatching=160, /* Enable long distance matching.
* This parameter is designed to improve the compression
* ratio for large inputs with long distance matches.
* This increases the memory usage as well as window size.
* Note: setting this parameter sets all the LDM parameters
* as well as ZSTD_p_windowLog. It should be set after
* ZSTD_p_compressionLevel and before ZSTD_p_windowLog and
* other LDM parameters. Setting the compression level
* after this parameter overrides the window log, though LDM
* will remain enabled until explicitly disabled. */
* This parameter is designed to improve compression ratio
* for large inputs, thanks to long distance matches.
* It increases memory usage and window size.
* Note: setting this parameter sets ZSTD_p_windowLog.
* Setting compression level after LDM overrides the window log,
* though LDM will remain enabled until explicitly disabled. */
ZSTD_p_ldmHashLog, /* Size of the table for long distance matching, as a power of 2.
* Larger values increase memory usage and compression ratio, but decrease
* compression speed.
* Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX
* (default: windowlog - 7).
* Special: value 0 means "do not change ldmHashLog". */
* Special: value 0 means "automatically determine hashlog". */
ZSTD_p_ldmMinMatch, /* Minimum size of searched matches for long distance matcher.
* Larger/too small values usually decrease compression ratio.
* Must be clamped between ZSTD_LDM_MINMATCH_MIN
* and ZSTD_LDM_MINMATCH_MAX (default: 64).
* Special: value 0 means "do not change ldmMinMatch". */
* Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX.
* Special: value 0 means "use default value" (default: 64). */
ZSTD_p_ldmBucketSizeLog, /* Log size of each bucket in the LDM hash table for collision resolution.
* Larger values usually improve collision resolution but may decrease
* compression speed.
* The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX (default: 3).
* note : 0 is a valid value */
* Larger values improve collision resolution but decrease compression speed.
* The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX .
* Special: value 0 means "use default value" (default: 3). */
ZSTD_p_ldmHashEveryLog, /* Frequency of inserting/looking up entries in the LDM hash table.
* The default is MAX(0, (windowLog - ldmHashLog)) to
* optimize hash table usage.
* Larger values improve compression speed. Deviating far from the
* default value will likely result in a decrease in compression ratio.
* Must be clamped between 0 and ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN.
* note : 0 is a valid value */
* Larger values improve compression speed.
* Deviating far from default value will likely result in a compression ratio decrease.
* Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN).
* Special: value 0 means "automatically determine hashEveryLog". */
/* frame parameters */
ZSTD_p_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1)