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

minor optimization for small files

Browse Source
This commit is contained in:
Yann Collet 2016-01-31 02:04:15 +01:00
parent e93d6ced17
commit 61e16ce07c
4 changed files with 32 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
lib/fse.c
View File

@ -848,10 +848,13 @@ size_t FSE_buildCTable_raw (FSE_CTable* ct, unsigned nbBits)
tableU16[s] = (U16)(tableSize + s);
/* Build Symbol Transformation Table */
{
const U32 deltaNbBits = (nbBits << 16) - (1 << nbBits);
for (s=0; s<=maxSymbolValue; s++) {
symbolTT[s].deltaNbBits = (nbBits << 16) - (1 << nbBits);
symbolTT[s].deltaNbBits = deltaNbBits;
symbolTT[s].deltaFindState = s-1;
}
}
return 0;
}

23
lib/zstd_compress.c
View File

@ -544,10 +544,11 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
}
/* Sequences Header */
if ((oend-op) < MIN_SEQUENCES_SIZE)
return ERROR(dstSize_tooSmall);
MEM_writeLE16(op, (U16)nbSeq); op+=2;
if ((oend-op) < MIN_SEQUENCES_SIZE) return ERROR(dstSize_tooSmall);
if (nbSeq < 128) *op++ = (BYTE)nbSeq;
else {
op[0] = (nbSeq>>8) + 128; op[1] = (BYTE)nbSeq; op+=2;
}
if (nbSeq==0) goto _check_compressibility;
/* dumps : contains rests of large lengths */
@ -946,12 +947,7 @@ void ZSTD_compressBlock_fast_generic(ZSTD_CCtx* zc,
/* init */
ZSTD_resetSeqStore(seqStorePtr);
if (ip < lowest+4) {
hashTable[ZSTD_hashPtr(lowest+1, hBits, mls)] = lowIndex+1;
hashTable[ZSTD_hashPtr(lowest+2, hBits, mls)] = lowIndex+2;
hashTable[ZSTD_hashPtr(lowest+3, hBits, mls)] = lowIndex+3;
ip = lowest+4;
}
if (ip < lowest+REPCODE_STARTVALUE) ip = lowest+REPCODE_STARTVALUE;
/* Main Search Loop */
while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
@ -1056,12 +1052,9 @@ void ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
/* init */
ZSTD_resetSeqStore(seqStorePtr);
/* skip first 4 positions to avoid read overflow during repcode match check */
/* skip first position to avoid read overflow during repcode match check */
hashTable[ZSTD_hashPtr(ip+0, hBits, mls)] = (U32)(ip-base+0);
hashTable[ZSTD_hashPtr(ip+1, hBits, mls)] = (U32)(ip-base+1);
hashTable[ZSTD_hashPtr(ip+2, hBits, mls)] = (U32)(ip-base+2);
hashTable[ZSTD_hashPtr(ip+3, hBits, mls)] = (U32)(ip-base+3);
ip += 4;
ip += REPCODE_STARTVALUE;
/* Main Search Loop */
while (ip < ilimit) { /* < instead of <=, because (ip+1) */

27
lib/zstd_decompress.c
View File

@ -273,7 +273,8 @@ void ZSTD_copyDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx)
static size_t ZSTD_decodeFrameHeader_Part1(ZSTD_DCtx* zc, const void* src, size_t srcSize)
{
U32 magicNumber;
if (srcSize != ZSTD_frameHeaderSize_min) return ERROR(srcSize_wrong);
if (srcSize != ZSTD_frameHeaderSize_min)
return ERROR(srcSize_wrong);
magicNumber = MEM_readLE32(src);
if (magicNumber != ZSTD_MAGICNUMBER) return ERROR(prefix_unknown);
zc->headerSize = ZSTD_frameHeaderSize_min;
@ -300,7 +301,8 @@ size_t ZSTD_getFrameParams(ZSTD_parameters* params, const void* src, size_t srcS
static size_t ZSTD_decodeFrameHeader_Part2(ZSTD_DCtx* zc, const void* src, size_t srcSize)
{
size_t result;
if (srcSize != zc->headerSize) return ERROR(srcSize_wrong);
if (srcSize != zc->headerSize)
return ERROR(srcSize_wrong);
result = ZSTD_getFrameParams(&(zc->params), src, srcSize);
if ((MEM_32bits()) && (zc->params.windowLog > 25)) return ERROR(frameParameter_unsupportedBy32bitsImplementation);
return result;
@ -313,7 +315,8 @@ size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, blockProperties_t* bp
BYTE headerFlags;
U32 cSize;
if (srcSize < 3) return ERROR(srcSize_wrong);
if (srcSize < 3)
return ERROR(srcSize_wrong);
headerFlags = *in;
cSize = in[2] + (in[1]<<8) + ((in[0] & 7)<<16);
@ -335,7 +338,7 @@ static size_t ZSTD_copyRawBlock(void* dst, size_t maxDstSize, const void* src, s
}
/** ZSTD_decodeLiteralsBlock
/*! ZSTD_decodeLiteralsBlock
@return : nb of bytes read from src (< srcSize ) */
size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
const void* src, size_t srcSize) /* note : srcSize < BLOCKSIZE */
@ -426,8 +429,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
break;
}
if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) /* risk reading beyond src buffer with wildcopy */
{
if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */
if (litSize > srcSize-lhSize) return ERROR(corruption_detected);
memcpy(dctx->litBuffer, istart+lhSize, litSize);
dctx->litPtr = dctx->litBuffer;
@ -483,11 +485,14 @@ size_t ZSTD_decodeSeqHeaders(int* nbSeq, const BYTE** dumpsPtr, size_t* dumpsLen
size_t dumpsLength;
/* check */
if (srcSize < MIN_SEQUENCES_SIZE) return ERROR(srcSize_wrong);
if (srcSize < MIN_SEQUENCES_SIZE)
return ERROR(srcSize_wrong);
/* SeqHead */
*nbSeq = MEM_readLE16(ip); ip+=2;
if (*nbSeq==0) return 2;
*nbSeq = *ip++;
if (*nbSeq==0) return 1;
if (*nbSeq >= 128)
*nbSeq = ((nbSeq[0]-128)<<8) + *ip++;
LLtype = *ip >> 6;
Offtype = (*ip >> 4) & 3;
@ -787,10 +792,10 @@ static size_t ZSTD_decompressSequences(
seqState_t seqState;
memset(&sequence, 0, sizeof(sequence));
sequence.offset = 4;
sequence.offset = REPCODE_STARTVALUE;
seqState.dumps = dumps;
seqState.dumpsEnd = dumps + dumpsLength;
seqState.prevOffset = 4;
seqState.prevOffset = REPCODE_STARTVALUE;
errorCode = BIT_initDStream(&(seqState.DStream), ip, iend-ip);
if (ERR_isError(errorCode)) return ERROR(corruption_detected);
FSE_initDState(&(seqState.stateLL), &(seqState.DStream), DTableLL);

4
lib/zstd_internal.h
View File

@ -81,7 +81,7 @@ static const size_t ZSTD_frameHeaderSize_min = 5;
#define IS_RLE 3
#define MINMATCH 4
#define REPCODE_STARTVALUE 4
#define REPCODE_STARTVALUE 1
#define MLbits 7
#define LLbits 6
@ -102,7 +102,7 @@ static const size_t ZSTD_frameHeaderSize_min = 5;
#define HufLog 12
#define MIN_SEQUENCES_SIZE 2 /*seqNb*/
#define MIN_SEQUENCES_SIZE 1 /* seqNb */
#define MIN_CBLOCK_SIZE (1 /*litCSize*/ + MIN_SEQUENCES_SIZE)
#define WILDCOPY_OVERLENGTH 8