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Merge pull request #584 from terrelln/huff-repeat

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Allow compressor to repeat Huffman tables
This commit is contained in:
Yann Collet
2017-03-02 17:20:11 -08:00
committed by GitHub
parent e02409fdc3 d051cd5b43
commit f44b55c18d
3 changed files with 153 additions and 45 deletions
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lib/compress/zstd_compress.c
+31 -16
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@@ -79,10 +79,11 @@ struct ZSTD_CCtx_s {
U32* chainTable;
HUF_CElt* hufTable;
U32 flagStaticTables;
HUF_repeat flagStaticHufTable;
FSE_CTable offcodeCTable [FSE_CTABLE_SIZE_U32(OffFSELog, MaxOff)];
FSE_CTable matchlengthCTable[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML)];
FSE_CTable litlengthCTable [FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL)];
unsigned tmpCounters[1024];
unsigned tmpCounters[HUF_WORKSPACE_SIZE_U32];
};
ZSTD_CCtx* ZSTD_createCCtx(void)
@@ -252,8 +253,11 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
ZSTD_compResetPolicy_e const crp)
{
if (crp == ZSTDcrp_continue)
if (ZSTD_equivalentParams(params, zc->params))
if (ZSTD_equivalentParams(params, zc->params)) {
zc->flagStaticTables = 0;
zc->flagStaticHufTable = HUF_repeat_none;
return ZSTD_continueCCtx(zc, params, frameContentSize);
}
{ size_t const blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, (size_t)1 << params.cParams.windowLog);
U32 const divider = (params.cParams.searchLength==3) ? 3 : 4;
@@ -287,6 +291,7 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
ptr = zc->hashTable3 + h3Size;
zc->hufTable = (HUF_CElt*)ptr;
zc->flagStaticTables = 0;
zc->flagStaticHufTable = HUF_repeat_none;
ptr = ((U32*)ptr) + 256; /* note : HUF_CElt* is incomplete type, size is simulated using U32 */
zc->nextToUpdate = 1;
@@ -372,12 +377,15 @@ size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx, unsigned long
/* copy entropy tables */
dstCCtx->flagStaticTables = srcCCtx->flagStaticTables;
dstCCtx->flagStaticHufTable = srcCCtx->flagStaticHufTable;
if (srcCCtx->flagStaticTables) {
memcpy(dstCCtx->hufTable, srcCCtx->hufTable, 256*4);
memcpy(dstCCtx->litlengthCTable, srcCCtx->litlengthCTable, sizeof(dstCCtx->litlengthCTable));
memcpy(dstCCtx->matchlengthCTable, srcCCtx->matchlengthCTable, sizeof(dstCCtx->matchlengthCTable));
memcpy(dstCCtx->offcodeCTable, srcCCtx->offcodeCTable, sizeof(dstCCtx->offcodeCTable));
}
if (srcCCtx->flagStaticHufTable) {
memcpy(dstCCtx->hufTable, srcCCtx->hufTable, 256*4);
}
return 0;
}
@@ -491,24 +499,27 @@ static size_t ZSTD_compressLiterals (ZSTD_CCtx* zc,
/* small ? don't even attempt compression (speed opt) */
# define LITERAL_NOENTROPY 63
{ size_t const minLitSize = zc->flagStaticTables ? 6 : LITERAL_NOENTROPY;
{ size_t const minLitSize = zc->flagStaticHufTable == HUF_repeat_valid ? 6 : LITERAL_NOENTROPY;
if (srcSize <= minLitSize) return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
}
if (dstCapacity < lhSize+1) return ERROR(dstSize_tooSmall); /* not enough space for compression */
if (zc->flagStaticTables && (lhSize==3)) {
hType = set_repeat;
singleStream = 1;
cLitSize = HUF_compress1X_usingCTable(ostart+lhSize, dstCapacity-lhSize, src, srcSize, zc->hufTable);
} else {
cLitSize = singleStream ? HUF_compress1X_wksp(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 11, zc->tmpCounters, sizeof(zc->tmpCounters))
: HUF_compress4X_wksp(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 11, zc->tmpCounters, sizeof(zc->tmpCounters));
{ HUF_repeat repeat = zc->flagStaticHufTable;
if (repeat == HUF_repeat_valid && lhSize == 3) singleStream = 1;
cLitSize = singleStream ? HUF_compress1X_repeat(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 11, zc->tmpCounters, sizeof(zc->tmpCounters), zc->hufTable, &repeat)
: HUF_compress4X_repeat(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 11, zc->tmpCounters, sizeof(zc->tmpCounters), zc->hufTable, &repeat);
if (repeat != HUF_repeat_none) { hType = set_repeat; } /* reused the existing table */
else { zc->flagStaticHufTable = HUF_repeat_check; } /* now have a table to reuse */
}
if ((cLitSize==0) | (cLitSize >= srcSize - minGain))
if ((cLitSize==0) | (cLitSize >= srcSize - minGain)) {
zc->flagStaticHufTable = HUF_repeat_none;
return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
if (cLitSize==1)
}
if (cLitSize==1) {
zc->flagStaticHufTable = HUF_repeat_none;
return ZSTD_compressRleLiteralsBlock(dst, dstCapacity, src, srcSize);
}
/* Build header */
switch(lhSize)
@@ -772,9 +783,12 @@ MEM_STATIC size_t ZSTD_compressSequences (ZSTD_CCtx* zc,
/* check compressibility */
_check_compressibility:
{ size_t const minGain = ZSTD_minGain(srcSize);
size_t const maxCSize = srcSize - minGain;
if ((size_t)(op-ostart) >= maxCSize) return 0; }
{ size_t const minGain = ZSTD_minGain(srcSize);
size_t const maxCSize = srcSize - minGain;
if ((size_t)(op-ostart) >= maxCSize) {
zc->flagStaticHufTable = HUF_repeat_none;
return 0;
} }
/* confirm repcodes */
{ int i; for (i=0; i<ZSTD_REP_NUM; i++) zc->rep[i] = zc->repToConfirm[i]; }
@@ -2624,6 +2638,7 @@ static size_t ZSTD_loadDictEntropyStats(ZSTD_CCtx* cctx, const void* dict, size_
}
cctx->flagStaticTables = 1;
cctx->flagStaticHufTable = HUF_repeat_valid;
return dictPtr - (const BYTE*)dict;
}