692 lines
29 KiB
C
692 lines
29 KiB
C
/*
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* Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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#include "zstd_compress_internal.h"
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#include "zstd_opt.h"
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#include "zstd_lazy.h" /* ZSTD_updateTree, ZSTD_updateTree_extDict */
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#define ZSTD_LITFREQ_ADD 2 /* scaling factor for litFreq, so that frequencies adapt faster to new stats. Also used for matchSum (?) */
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#define ZSTD_FREQ_DIV 4 /* log factor when using previous stats to init next stats */
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#define ZSTD_MAX_PRICE (1<<30)
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/*-*************************************
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* Price functions for optimal parser
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***************************************/
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static void ZSTD_setLog2Prices(optState_t* optPtr)
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{
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optPtr->log2litSum = ZSTD_highbit32(optPtr->litSum+1);
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optPtr->log2litLengthSum = ZSTD_highbit32(optPtr->litLengthSum+1);
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optPtr->log2matchLengthSum = ZSTD_highbit32(optPtr->matchLengthSum+1);
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optPtr->log2offCodeSum = ZSTD_highbit32(optPtr->offCodeSum+1);
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optPtr->factor = 1 + ((optPtr->litSum>>5) / optPtr->litLengthSum)
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+ ((optPtr->litSum<<1) / (optPtr->litSum + optPtr->matchSum)); /* => {0,1}, == (optPtr->matchSum <= optPtr->litSum) */
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}
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static void ZSTD_rescaleFreqs(optState_t* optPtr, const BYTE* src, size_t srcSize)
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{
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optPtr->cachedLiterals = NULL;
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optPtr->cachedPrice = optPtr->cachedLitLength = 0;
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optPtr->staticPrices = 0;
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if (optPtr->litLengthSum == 0) { /* first init */
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unsigned u;
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if (srcSize <= 1024) optPtr->staticPrices = 1;
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assert(optPtr->litFreq!=NULL);
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for (u=0; u<=MaxLit; u++)
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optPtr->litFreq[u] = 0;
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for (u=0; u<srcSize; u++)
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optPtr->litFreq[src[u]]++;
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optPtr->litSum = 0;
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for (u=0; u<=MaxLit; u++) {
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optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> ZSTD_FREQ_DIV);
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optPtr->litSum += optPtr->litFreq[u];
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}
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for (u=0; u<=MaxLL; u++)
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optPtr->litLengthFreq[u] = 1;
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optPtr->litLengthSum = MaxLL+1;
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for (u=0; u<=MaxML; u++)
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optPtr->matchLengthFreq[u] = 1;
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optPtr->matchLengthSum = MaxML+1;
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optPtr->matchSum = (ZSTD_LITFREQ_ADD << Litbits);
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for (u=0; u<=MaxOff; u++)
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optPtr->offCodeFreq[u] = 1;
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optPtr->offCodeSum = (MaxOff+1);
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} else {
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unsigned u;
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optPtr->litSum = 0;
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for (u=0; u<=MaxLit; u++) {
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optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> (ZSTD_FREQ_DIV+1));
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optPtr->litSum += optPtr->litFreq[u];
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}
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optPtr->litLengthSum = 0;
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for (u=0; u<=MaxLL; u++) {
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optPtr->litLengthFreq[u] = 1 + (optPtr->litLengthFreq[u]>>(ZSTD_FREQ_DIV+1));
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optPtr->litLengthSum += optPtr->litLengthFreq[u];
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}
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optPtr->matchLengthSum = 0;
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optPtr->matchSum = 0;
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for (u=0; u<=MaxML; u++) {
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optPtr->matchLengthFreq[u] = 1 + (optPtr->matchLengthFreq[u]>>ZSTD_FREQ_DIV);
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optPtr->matchLengthSum += optPtr->matchLengthFreq[u];
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optPtr->matchSum += optPtr->matchLengthFreq[u] * (u + 3);
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}
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optPtr->matchSum *= ZSTD_LITFREQ_ADD;
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optPtr->offCodeSum = 0;
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for (u=0; u<=MaxOff; u++) {
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optPtr->offCodeFreq[u] = 1 + (optPtr->offCodeFreq[u]>>ZSTD_FREQ_DIV);
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optPtr->offCodeSum += optPtr->offCodeFreq[u];
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}
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}
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ZSTD_setLog2Prices(optPtr);
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}
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static U32 ZSTD_getLiteralPrice(optState_t* const optPtr,
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U32 const litLength, const BYTE* const literals)
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{
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U32 price;
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if (optPtr->staticPrices)
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return ZSTD_highbit32((U32)litLength+1) + (litLength*6); /* 6 bit per literal - no statistic used */
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if (litLength == 0)
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return optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[0]+1);
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/* literals */
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if (optPtr->cachedLiterals == literals) {
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U32 u;
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U32 const additional = litLength - optPtr->cachedLitLength;
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const BYTE* const literals2 = optPtr->cachedLiterals + optPtr->cachedLitLength;
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price = optPtr->cachedPrice + additional * optPtr->log2litSum;
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for (u=0; u < additional; u++)
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price -= ZSTD_highbit32(optPtr->litFreq[literals2[u]]+1);
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optPtr->cachedPrice = price;
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optPtr->cachedLitLength = litLength;
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} else {
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U32 u;
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price = litLength * optPtr->log2litSum;
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for (u=0; u < litLength; u++)
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price -= ZSTD_highbit32(optPtr->litFreq[literals[u]]+1);
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if (litLength >= 12) {
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optPtr->cachedLiterals = literals;
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optPtr->cachedPrice = price;
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optPtr->cachedLitLength = litLength;
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}
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}
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/* literal Length */
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{ U32 const llCode = ZSTD_LLcode(litLength);
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price += LL_bits[llCode] + optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1);
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}
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return price;
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}
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/* ZSTD_getPrice() :
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* optLevel: when <2, favors small offset for decompression speed (improved cache efficiency) */
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FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr,
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U32 const litLength, const BYTE* const literals, U32 const offset, U32 const matchLength,
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int const optLevel)
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{
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U32 price;
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U32 const offCode = ZSTD_highbit32(offset+1);
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U32 const mlBase = matchLength - MINMATCH;
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assert(matchLength >= MINMATCH);
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if (optPtr->staticPrices) /* fixed scheme, do not use statistics */
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return ZSTD_getLiteralPrice(optPtr, litLength, literals) + ZSTD_highbit32((U32)mlBase+1) + 16 + offCode;
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price = offCode + optPtr->log2offCodeSum - ZSTD_highbit32(optPtr->offCodeFreq[offCode]+1);
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if ((optLevel<2) /*static*/ && offCode >= 20) price += (offCode-19)*2; /* handicap for long distance offsets, favor decompression speed */
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/* match Length */
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{ U32 const mlCode = ZSTD_MLcode(mlBase);
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price += ML_bits[mlCode] + optPtr->log2matchLengthSum - ZSTD_highbit32(optPtr->matchLengthFreq[mlCode]+1);
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}
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price += ZSTD_getLiteralPrice(optPtr, litLength, literals) + optPtr->factor;
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DEBUGLOG(8, "ZSTD_getPrice(ll:%u, ml:%u) = %u", litLength, matchLength, price);
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return price;
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}
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static void ZSTD_updateStats(optState_t* optPtr, U32 litLength, const BYTE* literals, U32 offsetCode, U32 matchLength)
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{
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/* literals */
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{ U32 u;
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for (u=0; u < litLength; u++)
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optPtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
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optPtr->litSum += litLength*ZSTD_LITFREQ_ADD;
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}
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/* literal Length */
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{ U32 const llCode = ZSTD_LLcode(litLength);
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optPtr->litLengthFreq[llCode]++;
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optPtr->litLengthSum++;
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}
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/* match offset code (0-2=>repCode; 3+=>offset+2) */
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{ U32 const offCode = ZSTD_highbit32(offsetCode+1);
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assert(offCode <= MaxOff);
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optPtr->offCodeFreq[offCode]++;
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optPtr->offCodeSum++;
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}
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/* match Length */
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{ U32 const mlBase = matchLength - MINMATCH;
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U32 const mlCode = ZSTD_MLcode(mlBase);
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optPtr->matchLengthFreq[mlCode]++;
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optPtr->matchLengthSum++;
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}
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}
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/* function safe only for comparisons */
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MEM_STATIC U32 ZSTD_readMINMATCH(const void* memPtr, U32 length)
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{
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switch (length)
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{
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default :
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case 4 : return MEM_read32(memPtr);
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case 3 : if (MEM_isLittleEndian())
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return MEM_read32(memPtr)<<8;
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else
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return MEM_read32(memPtr)>>8;
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}
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}
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/* Update hashTable3 up to ip (excluded)
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Assumption : always within prefix (i.e. not within extDict) */
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static U32 ZSTD_insertAndFindFirstIndexHash3 (ZSTD_CCtx* zc, const BYTE* ip)
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{
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U32* const hashTable3 = zc->hashTable3;
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U32 const hashLog3 = zc->hashLog3;
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const BYTE* const base = zc->base;
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U32 idx = zc->nextToUpdate3;
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U32 const target = zc->nextToUpdate3 = (U32)(ip - base);
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size_t const hash3 = ZSTD_hash3Ptr(ip, hashLog3);
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while(idx < target) {
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hashTable3[ZSTD_hash3Ptr(base+idx, hashLog3)] = idx;
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idx++;
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}
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return hashTable3[hash3];
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}
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/*-*************************************
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* Binary Tree search
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***************************************/
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FORCE_INLINE_TEMPLATE
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U32 ZSTD_insertBtAndGetAllMatches (
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ZSTD_CCtx* zc,
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const BYTE* const ip, const BYTE* const iLimit, const int extDict,
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U32 nbCompares, U32 const mls, U32 const sufficient_len,
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U32 rep[ZSTD_REP_NUM], U32 const ll0,
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ZSTD_match_t* matches, const U32 lengthToBeat)
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{
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const BYTE* const base = zc->base;
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U32 const current = (U32)(ip-base);
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U32 const hashLog = zc->appliedParams.cParams.hashLog;
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U32 const minMatch = (mls==3) ? 3 : 4;
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U32* const hashTable = zc->hashTable;
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size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
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U32 matchIndex = hashTable[h];
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U32* const bt = zc->chainTable;
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U32 const btLog = zc->appliedParams.cParams.chainLog - 1;
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U32 const btMask= (1U << btLog) - 1;
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size_t commonLengthSmaller=0, commonLengthLarger=0;
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const BYTE* const dictBase = zc->dictBase;
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U32 const dictLimit = zc->dictLimit;
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const BYTE* const dictEnd = dictBase + dictLimit;
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const BYTE* const prefixStart = base + dictLimit;
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U32 const btLow = btMask >= current ? 0 : current - btMask;
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U32 const windowLow = zc->lowLimit;
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U32* smallerPtr = bt + 2*(current&btMask);
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U32* largerPtr = bt + 2*(current&btMask) + 1;
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U32 matchEndIdx = current+8+1; /* farthest referenced position of any match => detects repetitive patterns */
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U32 dummy32; /* to be nullified at the end */
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U32 mnum = 0;
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size_t bestLength = lengthToBeat-1;
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DEBUGLOG(7, "ZSTD_insertBtAndGetAllMatches");
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/* check repCode */
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{ U32 const lastR = ZSTD_REP_NUM + ll0;
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U32 repCode;
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for (repCode = ll0; repCode < lastR; repCode++) {
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U32 const repOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
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U32 const repIndex = current - repOffset;
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U32 repLen = 0;
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assert(current >= dictLimit);
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if (repOffset-1 /* intentional overflow, discards 0 and -1 */ < current-dictLimit) { /* equivalent to `current > repIndex >= dictLimit` */
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if (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repOffset, minMatch)) {
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repLen = (U32)ZSTD_count(ip+minMatch, ip+minMatch-repOffset, iLimit) + minMatch;
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}
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} else { /* repIndex < dictLimit || repIndex >= current */
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const BYTE* const repMatch = dictBase + repIndex;
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assert(current >= windowLow);
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if ( extDict /* this case only valid in extDict mode */
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&& ( ((repOffset-1) /*intentional overflow*/ < current - windowLow) /* equivalent to `current > repIndex >= windowLow` */
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& (((U32)((dictLimit-1) - repIndex) >= 3) ) /* intentional overflow : do not test positions overlapping 2 memory segments */)
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&& (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) {
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repLen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iLimit, dictEnd, prefixStart) + minMatch;
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} }
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/* save longer solution */
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if (repLen > bestLength) {
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DEBUGLOG(8, "found rep-match %u of length %u",
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repCode - ll0, (U32)repLen);
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bestLength = repLen;
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matches[mnum].off = repCode - ll0;
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matches[mnum].len = (U32)repLen;
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mnum++;
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if ( (repLen > sufficient_len)
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| (ip+repLen == iLimit) ) { /* best possible */
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return mnum;
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} } } }
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/* HC3 match finder */
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if ((mls == 3) /*static*/ && (bestLength < mls)) {
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U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3 (zc, ip);
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if ((matchIndex3 > windowLow)
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& (current - matchIndex3 < (1<<18)) /*heuristic : longer distance likely too expensive*/ ) {
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size_t mlen;
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if ((!extDict) /*static*/ || (matchIndex3 >= dictLimit)) {
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const BYTE* const match = base + matchIndex3;
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mlen = ZSTD_count(ip, match, iLimit);
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} else {
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const BYTE* const match = dictBase + matchIndex3;
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mlen = ZSTD_count_2segments(ip, match, iLimit, dictEnd, prefixStart);
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}
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/* save best solution */
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if (mlen >= mls /* == 3 > bestLength */) {
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DEBUGLOG(8, "found small match with hlog3, of length %u",
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(U32)mlen);
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bestLength = mlen;
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assert(current > matchIndex3);
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assert(mnum==0); /* no prior solution */
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matches[0].off = (current - matchIndex3) + ZSTD_REP_MOVE;
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matches[0].len = (U32)mlen;
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mnum = 1;
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if ( (mlen > sufficient_len) |
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(ip+mlen == iLimit) ) { /* best possible length */
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zc->nextToUpdate = current+1; /* skip insertion */
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return 1;
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} } } }
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hashTable[h] = current; /* Update Hash Table */
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while (nbCompares-- && (matchIndex > windowLow)) {
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U32* const nextPtr = bt + 2*(matchIndex & btMask);
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size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
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const BYTE* match;
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assert(current > matchIndex);
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if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
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assert(matchIndex+matchLength >= dictLimit); /* ensure the condition is correct when !extDict */
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match = base + matchIndex;
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matchLength += ZSTD_count(ip+matchLength, match+matchLength, iLimit);
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} else {
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match = dictBase + matchIndex;
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matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dictEnd, prefixStart);
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if (matchIndex+matchLength >= dictLimit)
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match = base + matchIndex; /* prepare for match[matchLength] */
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}
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if (matchLength > bestLength) {
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DEBUGLOG(8, "found match of length %u at distance %u",
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(U32)matchLength, current - matchIndex);
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assert(matchEndIdx > matchIndex);
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if (matchLength > matchEndIdx - matchIndex)
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matchEndIdx = matchIndex + (U32)matchLength;
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bestLength = matchLength;
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matches[mnum].off = (current - matchIndex) + ZSTD_REP_MOVE;
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matches[mnum].len = (U32)matchLength;
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mnum++;
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if (matchLength > ZSTD_OPT_NUM) break;
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if (ip+matchLength == iLimit) { /* equal : no way to know if inf or sup */
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break; /* drop, to preserve bt consistency (miss a little bit of compression) */
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}
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}
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if (match[matchLength] < ip[matchLength]) {
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/* match smaller than current */
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*smallerPtr = matchIndex; /* update smaller idx */
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commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
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if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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smallerPtr = nextPtr+1; /* new candidate => larger than match, which was smaller than current */
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matchIndex = nextPtr[1]; /* new matchIndex, larger than previous, closer to current */
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} else {
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*largerPtr = matchIndex;
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commonLengthLarger = matchLength;
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if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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largerPtr = nextPtr;
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matchIndex = nextPtr[0];
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} }
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*smallerPtr = *largerPtr = 0;
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assert(matchEndIdx > current+8);
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zc->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */
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return mnum;
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}
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FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches (
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ZSTD_CCtx* zc, /* Index table will be updated */
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const BYTE* ip, const BYTE* const iHighLimit, int const extDict,
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U32 const maxNbAttempts, U32 const matchLengthSearch, U32 const sufficient_len,
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U32 rep[ZSTD_REP_NUM], U32 const ll0,
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ZSTD_match_t* matches, U32 const lengthToBeat)
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{
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DEBUGLOG(7, "ZSTD_BtGetAllMatches");
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if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
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if (extDict) ZSTD_updateTree_extDict(zc, ip, iHighLimit, maxNbAttempts, matchLengthSearch);
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else ZSTD_updateTree(zc, ip, iHighLimit, maxNbAttempts, matchLengthSearch);
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switch(matchLengthSearch)
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{
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case 3 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 3, sufficient_len, rep, ll0, matches, lengthToBeat);
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default :
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case 4 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 4, sufficient_len, rep, ll0, matches, lengthToBeat);
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case 5 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 5, sufficient_len, rep, ll0, matches, lengthToBeat);
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case 7 :
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case 6 : return ZSTD_insertBtAndGetAllMatches(zc, ip, iHighLimit, extDict, maxNbAttempts, 6, sufficient_len, rep, ll0, matches, lengthToBeat);
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}
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}
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/*-*******************************
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* Optimal parser
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*********************************/
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typedef struct repcodes_s {
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U32 rep[3];
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} repcodes_t;
|
|
|
|
repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0)
|
|
{
|
|
repcodes_t newReps;
|
|
if (offset >= ZSTD_REP_NUM) { /* full offset */
|
|
newReps.rep[2] = rep[1];
|
|
newReps.rep[1] = rep[0];
|
|
newReps.rep[0] = offset - ZSTD_REP_MOVE;
|
|
} else { /* repcode */
|
|
U32 const repCode = offset + ll0;
|
|
if (repCode > 0) { /* note : if repCode==0, no change */
|
|
U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
|
|
newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2];
|
|
newReps.rep[1] = rep[0];
|
|
newReps.rep[0] = currentOffset;
|
|
} else { /* repCode == 0 */
|
|
memcpy(&newReps, rep, sizeof(newReps));
|
|
}
|
|
}
|
|
return newReps;
|
|
}
|
|
|
|
/* update opt[pos] and last_pos */
|
|
#define SET_PRICE(pos, mlen_, offset_, litlen_, price_, rep_) \
|
|
{ \
|
|
while (last_pos < pos) { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; } \
|
|
opt[pos].mlen = mlen_; \
|
|
opt[pos].off = offset_; \
|
|
opt[pos].litlen = litlen_; \
|
|
opt[pos].price = price_; \
|
|
memcpy(opt[pos].rep, &rep_, sizeof(rep_)); \
|
|
}
|
|
|
|
FORCE_INLINE_TEMPLATE
|
|
size_t ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
|
|
const void* src, size_t srcSize,
|
|
const int optLevel, const int extDict)
|
|
{
|
|
seqStore_t* const seqStorePtr = &(ctx->seqStore);
|
|
optState_t* const optStatePtr = &(ctx->optState);
|
|
const BYTE* const istart = (const BYTE*)src;
|
|
const BYTE* ip = istart;
|
|
const BYTE* anchor = istart;
|
|
const BYTE* const iend = istart + srcSize;
|
|
const BYTE* const ilimit = iend - 8;
|
|
const BYTE* const base = ctx->base;
|
|
const BYTE* const prefixStart = base + ctx->dictLimit;
|
|
|
|
U32 const maxSearches = 1U << ctx->appliedParams.cParams.searchLog;
|
|
U32 const sufficient_len = MIN(ctx->appliedParams.cParams.targetLength, ZSTD_OPT_NUM -1);
|
|
U32 const mls = ctx->appliedParams.cParams.searchLength;
|
|
U32 const minMatch = (ctx->appliedParams.cParams.searchLength == 3) ? 3 : 4;
|
|
|
|
ZSTD_optimal_t* const opt = optStatePtr->priceTable;
|
|
ZSTD_match_t* const matches = optStatePtr->matchTable;
|
|
U32 rep[ZSTD_REP_NUM];
|
|
|
|
/* init */
|
|
DEBUGLOG(5, "ZSTD_compressBlock_opt_generic");
|
|
ctx->nextToUpdate3 = ctx->nextToUpdate;
|
|
ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize);
|
|
ip += (ip==prefixStart);
|
|
{ int i; for (i=0; i<ZSTD_REP_NUM; i++) rep[i]=seqStorePtr->rep[i]; }
|
|
|
|
/* Match Loop */
|
|
while (ip < ilimit) {
|
|
U32 cur, last_pos = 0;
|
|
U32 best_mlen, best_off;
|
|
|
|
/* find first match */
|
|
{ U32 const litlen = (U32)(ip - anchor);
|
|
U32 const ll0 = !litlen;
|
|
U32 const nbMatches = ZSTD_BtGetAllMatches(ctx, ip, iend, extDict, maxSearches, mls, sufficient_len, rep, ll0, matches, minMatch);
|
|
if (!nbMatches) { ip++; continue; }
|
|
|
|
/* initialize opt[0] */
|
|
{ U32 i ; for (i=0; i<ZSTD_REP_NUM; i++) opt[0].rep[i] = rep[i]; }
|
|
opt[0].mlen = 1;
|
|
opt[0].litlen = litlen;
|
|
|
|
/* large match -> immediate encoding */
|
|
{ U32 const maxML = matches[nbMatches-1].len;
|
|
DEBUGLOG(7, "found %u matches of maxLength=%u and offset=%u at cPos=%u => start new serie",
|
|
nbMatches, maxML, matches[nbMatches-1].off, (U32)(ip-prefixStart));
|
|
|
|
if (maxML > sufficient_len) {
|
|
best_mlen = maxML;
|
|
best_off = matches[nbMatches-1].off;
|
|
DEBUGLOG(7, "large match (%u>%u), immediate encoding",
|
|
best_mlen, sufficient_len);
|
|
cur = 0;
|
|
last_pos = 1;
|
|
goto _shortestPath;
|
|
} }
|
|
|
|
/* set prices for first matches starting position == 0 */
|
|
{ U32 pos = minMatch;
|
|
U32 matchNb;
|
|
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
|
|
U32 const offset = matches[matchNb].off;
|
|
U32 const end = matches[matchNb].len;
|
|
repcodes_t const repHistory = ZSTD_updateRep(rep, offset, ll0);
|
|
for ( ; pos <= end ; pos++) {
|
|
U32 const matchPrice = ZSTD_getPrice(optStatePtr, litlen, anchor, offset, pos, optLevel);
|
|
DEBUGLOG(7, "rPos:%u => set initial price : %u",
|
|
pos, matchPrice);
|
|
SET_PRICE(pos, pos, offset, litlen, matchPrice, repHistory); /* note : macro modifies last_pos */
|
|
} } }
|
|
}
|
|
|
|
/* check further positions */
|
|
for (cur = 1; cur <= last_pos; cur++) {
|
|
const BYTE* const inr = ip + cur;
|
|
assert(cur < ZSTD_OPT_NUM);
|
|
|
|
/* Fix current position with one literal if cheaper */
|
|
{ U32 const litlen = (opt[cur-1].mlen == 1) ? opt[cur-1].litlen + 1 : 1;
|
|
U32 price;
|
|
if (cur > litlen) {
|
|
price = opt[cur - litlen].price + ZSTD_getLiteralPrice(optStatePtr, litlen, inr-litlen);
|
|
} else {
|
|
price = ZSTD_getLiteralPrice(optStatePtr, litlen, anchor);
|
|
}
|
|
if (price <= opt[cur].price) {
|
|
DEBUGLOG(7, "rPos:%u : better price (%u<%u) using literal",
|
|
cur, price, opt[cur].price);
|
|
SET_PRICE(cur, 1/*mlen*/, 0/*offset*/, litlen, price, opt[cur-1].rep);
|
|
} }
|
|
|
|
/* last match must start at a minimum distance of 8 from oend */
|
|
if (inr > ilimit) continue;
|
|
|
|
if (cur == last_pos) break;
|
|
|
|
if ( (optLevel==0) /*static*/
|
|
&& (opt[cur+1].price <= opt[cur].price) )
|
|
continue; /* skip unpromising positions; about ~+6% speed, -0.01 ratio */
|
|
|
|
{ U32 const ll0 = (opt[cur].mlen != 1);
|
|
U32 const litlen = (opt[cur].mlen == 1) ? opt[cur].litlen : 0;
|
|
U32 const basePrice = (cur > litlen) ? opt[cur-litlen].price : 0;
|
|
const BYTE* const baseLiterals = ip + cur - litlen;
|
|
U32 const nbMatches = ZSTD_BtGetAllMatches(ctx, inr, iend, extDict, maxSearches, mls, sufficient_len, opt[cur].rep, ll0, matches, minMatch);
|
|
U32 matchNb;
|
|
if (!nbMatches) continue;
|
|
assert(baseLiterals >= prefixStart);
|
|
|
|
{ U32 const maxML = matches[nbMatches-1].len;
|
|
DEBUGLOG(7, "rPos:%u, found %u matches, of maxLength=%u",
|
|
cur, nbMatches, maxML);
|
|
|
|
if ( (maxML > sufficient_len)
|
|
| (cur + maxML >= ZSTD_OPT_NUM) ) {
|
|
best_mlen = maxML;
|
|
best_off = matches[nbMatches-1].off;
|
|
last_pos = cur + 1;
|
|
goto _shortestPath;
|
|
}
|
|
}
|
|
|
|
/* set prices using matches found at position == cur */
|
|
for (matchNb = 0; matchNb < nbMatches; matchNb++) {
|
|
U32 const offset = matches[matchNb].off;
|
|
repcodes_t const repHistory = ZSTD_updateRep(opt[cur].rep, offset, ll0);
|
|
U32 const lastML = matches[matchNb].len;
|
|
U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch;
|
|
U32 mlen;
|
|
|
|
DEBUGLOG(7, "testing match %u => offCode=%u, mlen=%u, llen=%u",
|
|
matchNb, matches[matchNb].off, lastML, litlen);
|
|
|
|
for (mlen = lastML; mlen >= startML; mlen--) {
|
|
U32 const pos = cur + mlen;
|
|
U32 const price = basePrice + ZSTD_getPrice(optStatePtr, litlen, baseLiterals, offset, mlen, optLevel);
|
|
|
|
if ((pos > last_pos) || (price < opt[pos].price)) {
|
|
DEBUGLOG(7, "rPos:%u => new better price (%u<%u)",
|
|
pos, price, opt[pos].price);
|
|
SET_PRICE(pos, mlen, offset, litlen, price, repHistory); /* note : macro modifies last_pos */
|
|
} else {
|
|
if (optLevel==0) break; /* gets ~+10% speed for about -0.01 ratio loss */
|
|
}
|
|
} } }
|
|
} /* for (cur = 1; cur <= last_pos; cur++) */
|
|
|
|
best_mlen = opt[last_pos].mlen;
|
|
best_off = opt[last_pos].off;
|
|
cur = last_pos - best_mlen;
|
|
|
|
_shortestPath: /* cur, last_pos, best_mlen, best_off have to be set */
|
|
assert(opt[0].mlen == 1);
|
|
|
|
/* reverse traversal */
|
|
DEBUGLOG(7, "start reverse traversal (last_pos:%u, cur:%u)",
|
|
last_pos, cur);
|
|
{ U32 selectedMatchLength = best_mlen;
|
|
U32 selectedOffset = best_off;
|
|
U32 pos = cur;
|
|
while (1) {
|
|
U32 const mlen = opt[pos].mlen;
|
|
U32 const off = opt[pos].off;
|
|
opt[pos].mlen = selectedMatchLength;
|
|
opt[pos].off = selectedOffset;
|
|
selectedMatchLength = mlen;
|
|
selectedOffset = off;
|
|
if (mlen > pos) break;
|
|
pos -= mlen;
|
|
} }
|
|
|
|
/* save sequences */
|
|
{ U32 pos;
|
|
for (pos=0; pos < last_pos; ) {
|
|
U32 const llen = (U32)(ip - anchor);
|
|
U32 const mlen = opt[pos].mlen;
|
|
U32 const offset = opt[pos].off;
|
|
if (mlen == 1) { ip++; pos++; continue; } /* literal position => move on */
|
|
pos += mlen; ip += mlen;
|
|
|
|
/* repcodes update : like ZSTD_updateRep(), but update in place */
|
|
if (offset >= ZSTD_REP_NUM) { /* full offset */
|
|
rep[2] = rep[1];
|
|
rep[1] = rep[0];
|
|
rep[0] = offset - ZSTD_REP_MOVE;
|
|
} else { /* repcode */
|
|
U32 const repCode = offset + (llen==0);
|
|
if (repCode) { /* note : if repCode==0, no change */
|
|
U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
|
|
if (repCode >= 2) rep[2] = rep[1];
|
|
rep[1] = rep[0];
|
|
rep[0] = currentOffset;
|
|
}
|
|
}
|
|
|
|
ZSTD_updateStats(optStatePtr, llen, anchor, offset, mlen);
|
|
ZSTD_storeSeq(seqStorePtr, llen, anchor, offset, mlen-MINMATCH);
|
|
anchor = ip;
|
|
} }
|
|
ZSTD_setLog2Prices(optStatePtr);
|
|
} /* while (ip < ilimit) */
|
|
|
|
/* Save reps for next block */
|
|
{ int i; for (i=0; i<ZSTD_REP_NUM; i++) seqStorePtr->repToConfirm[i] = rep[i]; }
|
|
|
|
/* Return the last literals size */
|
|
return iend - anchor;
|
|
}
|
|
|
|
|
|
size_t ZSTD_compressBlock_btopt(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
DEBUGLOG(5, "ZSTD_compressBlock_btopt");
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0 /*optLevel*/, 0 /*extDict*/);
|
|
}
|
|
|
|
size_t ZSTD_compressBlock_btultra(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 2 /*optLevel*/, 0 /*extDict*/);
|
|
}
|
|
|
|
size_t ZSTD_compressBlock_btopt_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0 /*optLevel*/, 1 /*extDict*/);
|
|
}
|
|
|
|
size_t ZSTD_compressBlock_btultra_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
return ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 2 /*optLevel*/, 1 /*extDict*/);
|
|
}
|