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fix compression ratio for blocks <= 16 KB

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This commit is contained in:
Yann Collet 2016-03-08 00:03:59 +01:00
parent 2486371008
commit 370b08e840
3 changed files with 30 additions and 26 deletions
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52
lib/zstd_compress.c
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@ -147,13 +147,14 @@ void ZSTD_validateParams(ZSTD_parameters* params)
const U32 btPlus = (params->strategy == ZSTD_btlazy2) || (params->strategy == ZSTD_btopt);
const U32 searchLengthMax = (params->strategy == ZSTD_fast) ? ZSTD_SEARCHLENGTH_MAX : ZSTD_SEARCHLENGTH_MAX-1;
const U32 searchLengthMin = (params->strategy == ZSTD_btopt) ? ZSTD_SEARCHLENGTH_MIN : ZSTD_SEARCHLENGTH_MIN+1;
const U32 hashLog3Min = (params->strategy == ZSTD_btopt) ? ZSTD_HASHLOG3_MIN : 0;
/* validate params */
if (MEM_32bits()) if (params->windowLog > 25) params->windowLog = 25; /* 32 bits mode cannot flush > 24 bits */
CLAMP(params->windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
CLAMP(params->contentLog, ZSTD_CONTENTLOG_MIN, ZSTD_CONTENTLOG_MAX);
CLAMP(params->hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
CLAMP(params->hashLog3, ZSTD_HASHLOG3_MIN, ZSTD_HASHLOG3_MAX);
CLAMP(params->hashLog3, hashLog3Min, ZSTD_HASHLOG3_MAX);
CLAMP(params->searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
CLAMP(params->searchLength, searchLengthMin, searchLengthMax);
CLAMP(params->targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
@ -174,10 +175,11 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
{ /* note : params considered validated here */
const size_t blockSize = MIN(BLOCKSIZE, (size_t)1 << params.windowLog);
/* reserve table memory */
const U32 contentLog = (params.strategy == ZSTD_fast) ? 1 : params.contentLog;
const U32 contentLog = (params.strategy == ZSTD_fast) ? 1 : params.contentLog;
const size_t tableSpace = ((1 << contentLog) + (1 << params.hashLog) + (1 << params.hashLog3)) * sizeof(U32);
const size_t neededSpace = tableSpace + (256*sizeof(U32)) + (3*blockSize)
+ ((params.strategy == ZSTD_btopt) ? ((1<<MLbits) + (1<<LLbits) + (1<<Offbits) + (1<<Litbits))*sizeof(U32) + (ZSTD_OPT_NUM+1)*(sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t)) : 0);
const size_t optSpace = ((1<<MLbits) + (1<<LLbits) + (1<<Offbits) + (1<<Litbits))*sizeof(U32) + (ZSTD_OPT_NUM+1)*(sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t));
const size_t neededSpace = tableSpace + (256*sizeof(U32)) /* huffTable */ + (3*blockSize)
+ ((params.strategy == ZSTD_btopt) ? optSpace : 0);
if (zc->workSpaceSize < neededSpace) {
free(zc->workSpace);
@ -204,7 +206,7 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
zc->blockSize = blockSize;
zc->seqStore.offsetStart = (U32*) (zc->seqStore.buffer);
zc->seqStore.offCodeStart = (BYTE*) (zc->seqStore.offsetStart) + blockSize;
zc->seqStore.offCodeStart = (BYTE*) (zc->seqStore.offsetStart + (blockSize>>2));
zc->seqStore.litStart = zc->seqStore.offCodeStart + (blockSize>>2);
zc->seqStore.litLengthStart = zc->seqStore.litStart + blockSize;
zc->seqStore.matchLengthStart = zc->seqStore.litLengthStart + (blockSize>>2);
@ -227,9 +229,9 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
}
/*! ZSTD_copyCCtx
* Duplicate an existing context @srcCCtx into another one @dstCCtx.
* Only works during stage 0 (i.e. before first call to ZSTD_compressContinue())
/*! ZSTD_copyCCtx() :
* Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
* Only works during stage 0 (i.e. before first call to ZSTD_compressContinue()).
* @return : 0, or an error code */
size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx)
{
@ -2363,7 +2365,7 @@ static const ZSTD_parameters ZSTD_defaultParameters[4][ZSTD_MAX_CLEVEL+1] = {
{ 0, 17, 18, 17, 0, 7, 4,128, ZSTD_btopt }, /* level 16 */
{ 0, 17, 18, 17, 0, 8, 4,128, ZSTD_btopt }, /* level 17 */
{ 0, 17, 18, 17, 0, 8, 4,256, ZSTD_btopt }, /* level 18 */
{ 0, 17, 18, 17, 0, 9, 4,256, ZSTD_btopt }, /* level 19 */
{ 0, 17, 18, 17, 16, 9, 3,256, ZSTD_btopt }, /* level 19 */
{ 0, 17, 18, 17, 0, 10, 4,512, ZSTD_btopt }, /* level 20 */
{ 0, 17, 18, 17, 0, 11, 4,512, ZSTD_btopt }, /* level 21 */
{ 0, 17, 18, 17, 0, 11, 4,512, ZSTD_btopt }, /* level 21-2 */
@ -2384,22 +2386,22 @@ static const ZSTD_parameters ZSTD_defaultParameters[4][ZSTD_MAX_CLEVEL+1] = {
{ 0, 14, 14, 14, 0, 6, 4, 4, ZSTD_lazy2 }, /* level 7.*/
{ 0, 14, 14, 14, 0, 7, 4, 4, ZSTD_lazy2 }, /* level 8.*/
{ 0, 14, 15, 14, 0, 6, 4, 4, ZSTD_btlazy2 }, /* level 9.*/
{ 0, 14, 15, 14, 0, 3, 3, 6, ZSTD_btopt }, /* level 10.*/
{ 0, 14, 15, 14, 0, 6, 3, 8, ZSTD_btopt }, /* level 11.*/
{ 0, 14, 15, 14, 0, 6, 3, 16, ZSTD_btopt }, /* level 12.*/
{ 0, 14, 15, 14, 0, 6, 3, 24, ZSTD_btopt }, /* level 13.*/
{ 0, 14, 15, 15, 0, 6, 3, 48, ZSTD_btopt }, /* level 14.*/
{ 0, 14, 15, 15, 0, 6, 3, 64, ZSTD_btopt }, /* level 15.*/
{ 0, 14, 15, 15, 0, 6, 3, 96, ZSTD_btopt }, /* level 16.*/
{ 0, 14, 15, 15, 0, 6, 3,128, ZSTD_btopt }, /* level 17.*/
{ 0, 14, 15, 15, 0, 6, 3,256, ZSTD_btopt }, /* level 18.*/
{ 0, 14, 15, 15, 0, 7, 3,256, ZSTD_btopt }, /* level 19.*/
{ 0, 14, 15, 15, 0, 8, 3,256, ZSTD_btopt }, /* level 20.*/
{ 0, 14, 15, 15, 0, 9, 3,256, ZSTD_btopt }, /* level 21.*/
{ 0, 14, 15, 15, 0, 10, 3,256, ZSTD_btopt }, /* level 22.*/
{ 0, 14, 15, 15, 0, 11, 3,256, ZSTD_btopt }, /* level 23.*/
{ 0, 14, 15, 15, 0, 12, 3,256, ZSTD_btopt }, /* level 24.*/
{ 0, 14, 15, 15, 0, 13, 3,256, ZSTD_btopt }, /* level 25.*/
{ 0, 14, 15, 14, 16, 3, 3, 6, ZSTD_btopt }, /* level 10.*/
{ 0, 14, 15, 14, 16, 6, 3, 8, ZSTD_btopt }, /* level 11.*/
{ 0, 14, 15, 14, 16, 6, 3, 16, ZSTD_btopt }, /* level 12.*/
{ 0, 14, 15, 14, 16, 6, 3, 24, ZSTD_btopt }, /* level 13.*/
{ 0, 14, 15, 15, 16, 6, 3, 48, ZSTD_btopt }, /* level 14.*/
{ 0, 14, 15, 15, 16, 6, 3, 64, ZSTD_btopt }, /* level 15.*/
{ 0, 14, 15, 15, 16, 6, 3, 96, ZSTD_btopt }, /* level 16.*/
{ 0, 14, 15, 15, 16, 6, 3,128, ZSTD_btopt }, /* level 17.*/
{ 0, 14, 15, 15, 16, 6, 3,256, ZSTD_btopt }, /* level 18.*/
{ 0, 14, 15, 15, 16, 7, 3,256, ZSTD_btopt }, /* level 19.*/
{ 0, 14, 15, 15, 16, 8, 3,256, ZSTD_btopt }, /* level 20.*/
{ 0, 14, 15, 15, 16, 9, 3,256, ZSTD_btopt }, /* level 21.*/
{ 0, 14, 15, 15, 16, 10, 3,256, ZSTD_btopt }, /* level 22.*/
{ 0, 14, 15, 15, 16, 11, 3,256, ZSTD_btopt }, /* level 23.*/
{ 0, 14, 15, 15, 16, 12, 3,256, ZSTD_btopt }, /* level 24.*/
{ 0, 14, 15, 15, 16, 13, 3,256, ZSTD_btopt }, /* level 25.*/
},
};

3
lib/zstd_decompress.c
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@ -822,7 +822,8 @@ static size_t ZSTD_decompressSequences(
nbSeq--;
ZSTD_decodeSequence(&sequence, &seqState, mls);
oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litLimit_8, base, vBase, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
if (ZSTD_isError(oneSeqSize))
return oneSeqSize;
op += oneSeqSize;
}

1
programs/fuzzer.c
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@ -344,6 +344,7 @@ static int basicUnitTests(U32 seed, double compressibility)
DISPLAYLEVEL(4, "OK \n");
/* nbSeq limit test */
if (0)
{
#define _3BYTESTESTLENGTH 131000
#define NB3BYTESSEQLOG 9