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zstd_opt.h: improved price function

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This commit is contained in:
Przemyslaw Skibinski
2016-11-23 17:22:54 +01:00
parent ad3e94512c
commit 9ca65af810
2 changed files with 34 additions and 14 deletions
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lib/common/zstd_internal.h
+1
View File
@@ -222,6 +222,7 @@ typedef struct {
U32 log2litSum;
U32 log2offCodeSum;
U32 factor;
U32 staticPrices;
U32 cachedPrice;
U32 cachedLitLength;
const BYTE* cachedLiterals;
lib/compress/zstd_opt.h
+33 -14
View File
@@ -15,8 +15,9 @@
#define ZSTD_OPT_H_91842398743
#define ZSTD_FREQ_DIV 5
#define ZSTD_MAX_PRICE (1<<30)
#define ZSTD_LITFREQ_ADD 2
#define ZSTD_FREQ_DIV 4
#define ZSTD_MAX_PRICE (1<<30)
/*-*************************************
* Price functions for optimal parser
@@ -31,22 +32,32 @@ FORCE_INLINE void ZSTD_setLog2Prices(seqStore_t* ssPtr)
}
MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr)
MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr, const BYTE* src, size_t srcSize)
{
unsigned u;
ssPtr->cachedLiterals = NULL;
ssPtr->cachedPrice = ssPtr->cachedLitLength = 0;
ssPtr->staticPrices = 0;
if (ssPtr->litLengthSum == 0) {
ssPtr->litSum = (2<<Litbits);
if (srcSize <= 1024) ssPtr->staticPrices = 1;
for (u=0; u<=MaxLit; u++)
ssPtr->litFreq[u] = 0;
for (u=0; u<srcSize; u++)
ssPtr->litFreq[src[u]]++;
ssPtr->litSum = 0;
ssPtr->litLengthSum = MaxLL+1;
ssPtr->matchLengthSum = MaxML+1;
ssPtr->offCodeSum = (MaxOff+1);
ssPtr->matchSum = (2<<Litbits);
ssPtr->matchSum = (ZSTD_LITFREQ_ADD<<Litbits);
for (u=0; u<=MaxLit; u++)
ssPtr->litFreq[u] = 2;
for (u=0; u<=MaxLit; u++) {
ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u]>>ZSTD_FREQ_DIV);
ssPtr->litSum += ssPtr->litFreq[u];
}
for (u=0; u<=MaxLL; u++)
ssPtr->litLengthFreq[u] = 1;
for (u=0; u<=MaxML; u++)
@@ -61,11 +72,11 @@ MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr)
ssPtr->litSum = 0;
for (u=0; u<=MaxLit; u++) {
ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u]>>ZSTD_FREQ_DIV);
ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u]>>(ZSTD_FREQ_DIV+1));
ssPtr->litSum += ssPtr->litFreq[u];
}
for (u=0; u<=MaxLL; u++) {
ssPtr->litLengthFreq[u] = 1 + (ssPtr->litLengthFreq[u]>>ZSTD_FREQ_DIV);
ssPtr->litLengthFreq[u] = 1 + (ssPtr->litLengthFreq[u]>>(ZSTD_FREQ_DIV+1));
ssPtr->litLengthSum += ssPtr->litLengthFreq[u];
}
for (u=0; u<=MaxML; u++) {
@@ -73,6 +84,7 @@ MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr)
ssPtr->matchLengthSum += ssPtr->matchLengthFreq[u];
ssPtr->matchSum += ssPtr->matchLengthFreq[u] * (u + 3);
}
ssPtr->matchSum *= ZSTD_LITFREQ_ADD;
for (u=0; u<=MaxOff; u++) {
ssPtr->offCodeFreq[u] = 1 + (ssPtr->offCodeFreq[u]>>ZSTD_FREQ_DIV);
ssPtr->offCodeSum += ssPtr->offCodeFreq[u];
@@ -87,6 +99,9 @@ FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t* ssPtr, U32 litLength, const BY
{
U32 price, u;
if (ssPtr->staticPrices)
return ZSTD_highbit32((U32)litLength+1) + (litLength*6);
if (litLength == 0)
return ssPtr->log2litLengthSum - ZSTD_highbit32(ssPtr->litLengthFreq[0]+1);
@@ -124,9 +139,13 @@ FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t* ssPtr, U32 litLength, const BY
FORCE_INLINE U32 ZSTD_getPrice(seqStore_t* seqStorePtr, U32 litLength, const BYTE* literals, U32 offset, U32 matchLength, const int ultra)
{
/* offset */
U32 price;
BYTE const offCode = (BYTE)ZSTD_highbit32(offset+1);
U32 price = offCode + seqStorePtr->log2offCodeSum - ZSTD_highbit32(seqStorePtr->offCodeFreq[offCode]+1);
if (seqStorePtr->staticPrices)
return ZSTD_getLiteralPrice(seqStorePtr, litLength, literals) + ZSTD_highbit32((U32)matchLength+1) + 16 + offCode;
price = offCode + seqStorePtr->log2offCodeSum - ZSTD_highbit32(seqStorePtr->offCodeFreq[offCode]+1);
if (!ultra && offCode >= 20) price += (offCode-19)*2;
/* match Length */
@@ -144,9 +163,9 @@ MEM_STATIC void ZSTD_updatePrice(seqStore_t* seqStorePtr, U32 litLength, const B
U32 u;
/* literals */
seqStorePtr->litSum += litLength;
seqStorePtr->litSum += litLength*ZSTD_LITFREQ_ADD;
for (u=0; u < litLength; u++)
seqStorePtr->litFreq[literals[u]]++;
seqStorePtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
/* literal Length */
{ const BYTE LL_deltaCode = 19;
@@ -401,7 +420,7 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
/* init */
ctx->nextToUpdate3 = ctx->nextToUpdate;
ZSTD_rescaleFreqs(seqStorePtr);
ZSTD_rescaleFreqs(seqStorePtr, src, srcSize);
ip += (ip==prefixStart);
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) rep[i]=ctx->rep[i]; }
@@ -656,7 +675,7 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) rep[i]=ctx->rep[i]; }
ctx->nextToUpdate3 = ctx->nextToUpdate;
ZSTD_rescaleFreqs(seqStorePtr);
ZSTD_rescaleFreqs(seqStorePtr, src, srcSize);
ip += (ip==prefixStart);
/* Match Loop */