AuroraMiddleware/zstd
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minor code refactoring

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This commit is contained in:
Yann Collet 2016-03-18 12:37:45 +01:00
parent 1d1ae40258
commit a910dc8238
1 changed files with 65 additions and 73 deletions
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138
lib/zstd_compress.c
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@ -445,7 +445,7 @@ size_t ZSTD_noCompressBlock (void* dst, size_t dstCapacity, const void* src, siz
static size_t ZSTD_noCompressLiterals (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
BYTE* const ostart = (BYTE* const)dst;
const U32 flSize = 1 + (srcSize>31) + (srcSize>4095);
U32 const flSize = 1 + (srcSize>31) + (srcSize>4095);
if (srcSize + flSize > dstCapacity) return ERROR(dstSize_tooSmall);
@ -473,7 +473,7 @@ static size_t ZSTD_noCompressLiterals (void* dst, size_t dstCapacity, const void
static size_t ZSTD_compressRleLiteralsBlock (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
BYTE* const ostart = (BYTE* const)dst;
U32 flSize = 1 + (srcSize>31) + (srcSize>4095);
U32 const flSize = 1 + (srcSize>31) + (srcSize>4095);
(void)dstCapacity; /* dstCapacity guaranteed to be >=4, hence large enough */
@ -486,7 +486,7 @@ static size_t ZSTD_compressRleLiteralsBlock (void* dst, size_t dstCapacity, cons
ostart[0] = (BYTE)((IS_RLE<<6) + (2<<4) + (srcSize >> 8));
ostart[1] = (BYTE)srcSize;
break;
default: /*note : should not be necessary : flSize is necessary within {1,2,3} */
default: /*note : should not be necessary : flSize is necessarily within {1,2,3} */
case 3: /* 2 - 2 - 20 */
ostart[0] = (BYTE)((IS_RLE<<6) + (3<<4) + (srcSize >> 16));
ostart[1] = (BYTE)(srcSize>>8);
@ -505,57 +505,57 @@ static size_t ZSTD_compressLiterals (ZSTD_CCtx* zc,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize)
{
const size_t minGain = ZSTD_minGain(srcSize);
size_t const minGain = ZSTD_minGain(srcSize);
size_t const lhSize = 3 + (srcSize >= 1 KB) + (srcSize >= 16 KB);
BYTE* const ostart = (BYTE*)dst;
const size_t lhSize = 3 + (srcSize >= 1 KB) + (srcSize >= 16 KB);
U32 singleStream = srcSize < 256;
U32 hType = IS_HUF;
size_t clitSize;
size_t cLitSize;
if (dstCapacity < lhSize+1) return ERROR(dstSize_tooSmall); /* not enough space for compression */
if (zc->flagStaticTables && (lhSize==3)) {
hType = IS_PCH;
singleStream = 1;
clitSize = HUF_compress1X_usingCTable(ostart+lhSize, dstCapacity-lhSize, src, srcSize, zc->hufTable);
cLitSize = HUF_compress1X_usingCTable(ostart+lhSize, dstCapacity-lhSize, src, srcSize, zc->hufTable);
} else {
clitSize = singleStream ? HUF_compress1X(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 12)
cLitSize = singleStream ? HUF_compress1X(ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 12)
: HUF_compress2 (ostart+lhSize, dstCapacity-lhSize, src, srcSize, 255, 12);
}
if ((clitSize==0) || (clitSize >= srcSize - minGain)) return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
if (clitSize==1) return ZSTD_compressRleLiteralsBlock(dst, dstCapacity, src, srcSize);
if ((cLitSize==0) || (cLitSize >= srcSize - minGain))
return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
if (cLitSize==1)
return ZSTD_compressRleLiteralsBlock(dst, dstCapacity, src, srcSize);
/* Build header */
switch(lhSize)
{
case 3: /* 2 - 2 - 10 - 10 */
ostart[0] = (BYTE)((srcSize>>6) + (singleStream << 4) + (hType<<6));
ostart[1] = (BYTE)((srcSize<<2) + (clitSize>>8));
ostart[2] = (BYTE)(clitSize);
ostart[1] = (BYTE)((srcSize<<2) + (cLitSize>>8));
ostart[2] = (BYTE)(cLitSize);
break;
case 4: /* 2 - 2 - 14 - 14 */
ostart[0] = (BYTE)((srcSize>>10) + (2<<4) + (hType<<6));
ostart[1] = (BYTE)(srcSize>> 2);
ostart[2] = (BYTE)((srcSize<<6) + (clitSize>>8));
ostart[3] = (BYTE)(clitSize);
ostart[2] = (BYTE)((srcSize<<6) + (cLitSize>>8));
ostart[3] = (BYTE)(cLitSize);
break;
default: /* should not be necessary, lhSize is {3,4,5} */
default: /* should not be necessary, lhSize is only {3,4,5} */
case 5: /* 2 - 2 - 18 - 18 */
ostart[0] = (BYTE)((srcSize>>14) + (3<<4) + (hType<<6));
ostart[1] = (BYTE)(srcSize>>6);
ostart[2] = (BYTE)((srcSize<<2) + (clitSize>>16));
ostart[3] = (BYTE)(clitSize>>8);
ostart[4] = (BYTE)(clitSize);
ostart[2] = (BYTE)((srcSize<<2) + (cLitSize>>16));
ostart[3] = (BYTE)(cLitSize>>8);
ostart[4] = (BYTE)(cLitSize);
break;
}
return lhSize+clitSize;
return lhSize+cLitSize;
}
#define LITERAL_NOENTROPY 63 /* don't even attempt to compress literals below this threshold (cheap heuristic) */
size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
void* dst, size_t dstCapacity,
size_t srcSize)
@ -563,36 +563,30 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
const seqStore_t* seqStorePtr = &(zc->seqStore);
U32 count[MaxSeq+1];
S16 norm[MaxSeq+1];
size_t mostFrequent;
U32 max;
FSE_CTable* CTable_LitLength = zc->litlengthCTable;
FSE_CTable* CTable_OffsetBits = zc->offcodeCTable;
FSE_CTable* CTable_MatchLength = zc->matchlengthCTable;
U32 LLtype, Offtype, MLtype; /* compressed, raw or rle */
const BYTE* const op_lit_start = seqStorePtr->litStart;
const BYTE* const llTable = seqStorePtr->litLengthStart;
const BYTE* const llPtr = seqStorePtr->litLength;
const BYTE* const mlTable = seqStorePtr->matchLengthStart;
const U32* const offsetTable = seqStorePtr->offsetStart;
BYTE* const offCodeTable = seqStorePtr->offCodeStart;
BYTE* const ostart = (BYTE*)dst;
BYTE* op = ostart;
BYTE* const oend = ostart + dstCapacity;
const size_t nbSeq = llPtr - llTable;
const size_t minGain = ZSTD_minGain(srcSize);
const size_t maxCSize = srcSize - minGain;
BYTE* op = ostart;
size_t const nbSeq = llPtr - llTable;
BYTE* seqHead;
/* Compress literals */
# define LITERAL_NOENTROPY 63 /* don't even attempt to compress literals below this threshold (cheap heuristic) */
{
size_t cSize;
size_t litSize = seqStorePtr->lit - op_lit_start;
const size_t minLitSize = zc->flagStaticTables ? 6 : LITERAL_NOENTROPY;
if (litSize <= minLitSize)
cSize = ZSTD_noCompressLiterals(op, dstCapacity, op_lit_start, litSize);
else
cSize = ZSTD_compressLiterals(zc, op, dstCapacity, op_lit_start, litSize);
const BYTE* const literals = seqStorePtr->litStart;
size_t const litSize = seqStorePtr->lit - literals;
size_t const minLitSize = zc->flagStaticTables ? 6 : LITERAL_NOENTROPY;
size_t const cSize = (litSize <= minLitSize) ?
ZSTD_noCompressLiterals(op, dstCapacity, literals, litSize) :
ZSTD_compressLiterals(zc, op, dstCapacity, literals, litSize);
if (ZSTD_isError(cSize)) return cSize;
op += cSize;
}
@ -609,7 +603,7 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
return ERROR(dstSize_tooSmall);
seqHead = op;
{
size_t dumpsLength = seqStorePtr->dumps - seqStorePtr->dumpsStart;
size_t const dumpsLength = seqStorePtr->dumps - seqStorePtr->dumpsStart;
if (dumpsLength < 512) {
op[0] = (BYTE)(dumpsLength >> 8);
op[1] = (BYTE)(dumpsLength);
@ -629,8 +623,8 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
#define MAX_SEQ_FOR_STATIC_FSE 1000
/* CTable for Literal Lengths */
max = MaxLL;
mostFrequent = FSE_countFast(count, &max, llTable, nbSeq);
{ U32 max = MaxLL;
size_t const mostFrequent = FSE_countFast(count, &max, llTable, nbSeq);
if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
*op++ = llTable[0];
FSE_buildCTable_rle(CTable_LitLength, (BYTE)max);
@ -643,7 +637,7 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
} else {
size_t NCountSize;
size_t nbSeq_1 = nbSeq;
U32 tableLog = FSE_optimalTableLog(LLFSELog, nbSeq, max);
const U32 tableLog = FSE_optimalTableLog(LLFSELog, nbSeq, max);
if (count[llTable[nbSeq-1]]>1) { count[llTable[nbSeq-1]]--; nbSeq_1--; }
FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
NCountSize = FSE_writeNCount(op, oend-op, norm, max, tableLog); /* overflow protected */
@ -651,17 +645,13 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
op += NCountSize;
FSE_buildCTable(CTable_LitLength, norm, max, tableLog);
LLtype = FSE_ENCODING_DYNAMIC;
}
}}
/* CTable for Offset codes */
{ /* create Offset codes */
size_t i; for (i=0; i<nbSeq; i++) {
offCodeTable[i] = (BYTE)ZSTD_highbit(offsetTable[i]) + 1;
if (offsetTable[i]==0) offCodeTable[i]=0;
}
}
max = MaxOff;
mostFrequent = FSE_countFast(count, &max, offCodeTable, nbSeq);
/* Offset codes */
{ size_t i; for (i=0; i<nbSeq; i++) offCodeTable[i] = offsetTable[i] ? (BYTE)ZSTD_highbit(offsetTable[i]) + 1 : 0; }
{ U32 max = MaxOff;
size_t const mostFrequent = FSE_countFast(count, &max, offCodeTable, nbSeq);
if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
*op++ = offCodeTable[0];
FSE_buildCTable_rle(CTable_OffsetBits, (BYTE)max);
@ -674,7 +664,7 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
} else {
size_t NCountSize;
size_t nbSeq_1 = nbSeq;
U32 tableLog = FSE_optimalTableLog(OffFSELog, nbSeq, max);
const U32 tableLog = FSE_optimalTableLog(OffFSELog, nbSeq, max);
if (count[offCodeTable[nbSeq-1]]>1) { count[offCodeTable[nbSeq-1]]--; nbSeq_1--; }
FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
NCountSize = FSE_writeNCount(op, oend-op, norm, max, tableLog); /* overflow protected */
@ -682,11 +672,11 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
op += NCountSize;
FSE_buildCTable(CTable_OffsetBits, norm, max, tableLog);
Offtype = FSE_ENCODING_DYNAMIC;
}
}}
/* CTable for MatchLengths */
max = MaxML;
mostFrequent = FSE_countFast(count, &max, mlTable, nbSeq);
{ U32 max = MaxML;
size_t const mostFrequent = FSE_countFast(count, &max, mlTable, nbSeq);
if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
*op++ = *mlTable;
FSE_buildCTable_rle(CTable_MatchLength, (BYTE)max);
@ -698,29 +688,27 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
MLtype = FSE_ENCODING_RAW;
} else {
size_t NCountSize;
U32 tableLog = FSE_optimalTableLog(MLFSELog, nbSeq, max);
const U32 tableLog = FSE_optimalTableLog(MLFSELog, nbSeq, max);
FSE_normalizeCount(norm, tableLog, count, nbSeq, max);
NCountSize = FSE_writeNCount(op, oend-op, norm, max, tableLog); /* overflow protected */
if (FSE_isError(NCountSize)) return ERROR(GENERIC);
op += NCountSize;
FSE_buildCTable(CTable_MatchLength, norm, max, tableLog);
MLtype = FSE_ENCODING_DYNAMIC;
}
}}
seqHead[0] += (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2));
zc->flagStaticTables = 0;
/* Encoding Sequences */
{
size_t streamSize, errorCode;
BIT_CStream_t blockStream;
FSE_CState_t stateMatchLength;
FSE_CState_t stateOffsetBits;
FSE_CState_t stateLitLength;
int i;
FSE_CState_t stateMatchLength;
FSE_CState_t stateOffsetBits;
FSE_CState_t stateLitLength;
errorCode = BIT_initCStream(&blockStream, op, oend-op);
if (ERR_isError(errorCode)) return ERROR(dstSize_tooSmall); /* not enough space remaining */
{ size_t const errorCode = BIT_initCStream(&blockStream, op, oend-op);
if (ERR_isError(errorCode)) return ERROR(dstSize_tooSmall); } /* not enough space remaining */
/* first symbols */
FSE_initCState2(&stateMatchLength, CTable_MatchLength, mlTable[nbSeq-1]);
@ -729,12 +717,12 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
BIT_addBits(&blockStream, offsetTable[nbSeq-1], offCodeTable[nbSeq-1] ? (offCodeTable[nbSeq-1]-1) : 0);
BIT_flushBits(&blockStream);
for (i=(int)nbSeq-2; i>=0; i--) {
BYTE mlCode = mlTable[i];
U32 offset = offsetTable[i];
BYTE offCode = offCodeTable[i]; /* 32b*/ /* 64b*/
U32 nbBits = (offCode-1) + (!offCode);
BYTE litLength = llTable[i]; /* (7)*/ /* (7)*/
{ int i; for (i=(int)nbSeq-2; i>=0; i--) {
const BYTE mlCode = mlTable[i];
const U32 offset = offsetTable[i];
const BYTE offCode = offCodeTable[i]; /* 32b*/ /* 64b*/
const U32 nbBits = (offCode-1) + (!offCode);
const BYTE litLength = llTable[i]; /* (7)*/ /* (7)*/
FSE_encodeSymbol(&blockStream, &stateMatchLength, mlCode); /* 17 */ /* 17 */
if (MEM_32bits()) BIT_flushBits(&blockStream); /* 7 */
FSE_encodeSymbol(&blockStream, &stateLitLength, litLength); /* 17 */ /* 27 */
@ -742,20 +730,24 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
if (MEM_32bits()) BIT_flushBits(&blockStream); /* 7 */
BIT_addBits(&blockStream, offset, nbBits); /* 31 */ /* 62 */ /* 24 bits max in 32-bits mode */
BIT_flushBits(&blockStream); /* 7 */ /* 7 */
}
}}
FSE_flushCState(&blockStream, &stateMatchLength);
FSE_flushCState(&blockStream, &stateOffsetBits);
FSE_flushCState(&blockStream, &stateLitLength);
streamSize = BIT_closeCStream(&blockStream);
{ size_t const streamSize = BIT_closeCStream(&blockStream);
if (streamSize==0) return ERROR(dstSize_tooSmall); /* not enough space */
op += streamSize;
op += streamSize; }
}
/* check compressibility */
_check_compressibility:
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) return 0;
}
return op - ostart;
}