AuroraMiddleware/zstd
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

minor compress sequence refactor

Browse Source
This commit is contained in:
Yann Collet 2015-08-08 02:16:11 +01:00
parent 56213d89f9
commit 8a46c159c5
1 changed files with 22 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
lib/zstd.c
View File

@ -158,6 +158,8 @@ static const U32 g_searchStrength = 8;
#define MLFSELog 10
#define LLFSELog 10
#define OffFSELog 9
#define MAX(a,b) ((a)<(b)?(b):(a))
#define MaxSeq MAX(MaxLL, MaxML)
#define LITERAL_NOENTROPY 63
#define COMMAND_NOENTROPY 7 /* to remove */
@ -575,26 +577,25 @@ static size_t ZSTD_compressSequences(BYTE* dst, size_t maxDstSize,
const seqStore_t* seqStorePtr,
size_t lastLLSize, size_t srcSize)
{
U32 count[256];
S16 norm[256];
U32 count[MaxSeq];
S16 norm[MaxSeq];
size_t mostFrequent;
U32 max = 255;
U32 tableLog = 11;
U32 CTable_LitLength [FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL )];
U32 CTable_OffsetBits [FSE_CTABLE_SIZE_U32(OffFSELog,MaxOff)];
U32 CTable_MatchLength[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML )];
U32 LLtype, Offtype, MLtype;
U32 LLtype, Offtype, MLtype; /* compressed, raw or rle */
const BYTE* const op_lit_start = seqStorePtr->litStart;
const BYTE* op_lit = seqStorePtr->lit;
const BYTE* const op_litLength_start = seqStorePtr->litLengthStart;
const BYTE* const llTable = seqStorePtr->litLengthStart;
const BYTE* op_litLength = seqStorePtr->litLength;
const U32* op_offset = seqStorePtr->offset;
const BYTE* op_matchLength = seqStorePtr->matchLength;
const size_t nbSeq = op_litLength - op_litLength_start;
const BYTE* const mlTable = seqStorePtr->matchLengthStart;
const U32* const offsetTable = seqStorePtr->offsetStart;
BYTE* const offCodeTable = seqStorePtr->offCodeStart;
BYTE* op = dst;
BYTE* const oend = dst + maxDstSize;
BYTE* const offsetBits_start = seqStorePtr->offCodeStart;
BYTE* offsetBitsPtr = offsetBits_start;
const size_t nbSeq = op_litLength - llTable;
const size_t minGain = ZSTD_minGain(srcSize);
const size_t maxCSize = srcSize - minGain;
const size_t minSeqSize = 1 /*lastL*/ + 2 /*dHead*/ + 2 /*dumpsIn*/ + 5 /*SeqHead*/ + 3 /*SeqIn*/ + 1 /*margin*/ + ZSTD_blockHeaderSize;
@ -622,13 +623,11 @@ static size_t ZSTD_compressSequences(BYTE* dst, size_t maxDstSize,
op += cSize;
}
/* Encode Sequences */
/* seqHeader */
/* Sequences Header */
op += ZSTD_writeProgressive(op, lastLLSize);
seqHead = op;
/* dumps */
/* dumps : contains too large lengths */
{
size_t dumpsLength = seqStorePtr->dumps - seqStorePtr->dumpsStart;
if (dumpsLength < 512)
@ -675,19 +674,17 @@ static size_t ZSTD_compressSequences(BYTE* dst, size_t maxDstSize,
{
/* create Offset codes */
size_t i;
const U32* const op_offset_start = seqStorePtr->offsetStart;
max = MaxOff;
for (i=0; i<nbSeq; i++)
{
offsetBits_start[i] = (BYTE)ZSTD_highbit(op_offset_start[i]) + 1;
if (op_offset_start[i]==0) offsetBits_start[i]=0;
offCodeTable[i] = (BYTE)ZSTD_highbit(offsetTable[i]) + 1;
if (offsetTable[i]==0) offCodeTable[i]=0;
}
offsetBitsPtr += nbSeq;
mostFrequent = FSE_countFast(count, &max, offsetBits_start, nbSeq);
mostFrequent = FSE_countFast(count, &max, offCodeTable, nbSeq);
}
if ((mostFrequent == nbSeq) && (nbSeq > 2))
{
*op++ = *offsetBits_start;
*op++ = *offCodeTable;
FSE_buildCTable_rle(CTable_OffsetBits, (BYTE)max);
Offtype = bt_rle;
}
@ -737,6 +734,7 @@ static size_t ZSTD_compressSequences(BYTE* dst, size_t maxDstSize,
FSE_CState_t stateMatchLength;
FSE_CState_t stateOffsetBits;
FSE_CState_t stateLitLength;
int i;
errorCode = FSE_initCStream(&blockStream, op, oend-op);
if (FSE_isError(errorCode)) return 0; /* not enough space remaining */
@ -744,13 +742,13 @@ static size_t ZSTD_compressSequences(BYTE* dst, size_t maxDstSize,
FSE_initCState(&stateOffsetBits, CTable_OffsetBits);
FSE_initCState(&stateLitLength, CTable_LitLength);
while (op_litLength > op_litLength_start)
for (i=nbSeq-1; i>=0; i--)
{
BYTE matchLength = *(--op_matchLength);
U32 offset = *(--op_offset);
BYTE offCode = *(--offsetBitsPtr); /* 32b*/ /* 64b*/
BYTE matchLength = mlTable[i];
U32 offset = offsetTable[i];
BYTE offCode = offCodeTable[i]; /* 32b*/ /* 64b*/
U32 nbBits = (offCode-1) * (!!offCode);
BYTE litLength = *(--op_litLength); /* (7)*/ /* (7)*/
BYTE litLength = llTable[i]; /* (7)*/ /* (7)*/
FSE_encodeSymbol(&blockStream, &stateMatchLength, matchLength); /* 17 */ /* 17 */
if (ZSTD_32bits()) FSE_flushBits(&blockStream); /* 7 */
FSE_addBits(&blockStream, offset, nbBits); /* 32 */ /* 42 */