diff options
Diffstat (limited to 'vendor/github.com/DataDog/zstd/zstd_opt.c')
| -rw-r--r-- | vendor/github.com/DataDog/zstd/zstd_opt.c | 1233 |
1 files changed, 0 insertions, 1233 deletions
diff --git a/vendor/github.com/DataDog/zstd/zstd_opt.c b/vendor/github.com/DataDog/zstd/zstd_opt.c deleted file mode 100644 index efb69d326..000000000 --- a/vendor/github.com/DataDog/zstd/zstd_opt.c +++ /dev/null @@ -1,1233 +0,0 @@ -/* - * Copyright (c) 2016-present, Przemyslaw Skibinski, Yann Collet, Facebook, Inc. - * All rights reserved. - * - * This source code is licensed under both the BSD-style license (found in the - * LICENSE file in the root directory of this source tree) and the GPLv2 (found - * in the COPYING file in the root directory of this source tree). - * You may select, at your option, one of the above-listed licenses. - */ - -#include "zstd_compress_internal.h" -#include "hist.h" -#include "zstd_opt.h" - - -#define ZSTD_LITFREQ_ADD 2 /* scaling factor for litFreq, so that frequencies adapt faster to new stats */ -#define ZSTD_FREQ_DIV 4 /* log factor when using previous stats to init next stats */ -#define ZSTD_MAX_PRICE (1<<30) - -#define ZSTD_PREDEF_THRESHOLD 1024 /* if srcSize < ZSTD_PREDEF_THRESHOLD, symbols' cost is assumed static, directly determined by pre-defined distributions */ - - -/*-************************************* -* Price functions for optimal parser -***************************************/ - -#if 0 /* approximation at bit level */ -# define BITCOST_ACCURACY 0 -# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY) -# define WEIGHT(stat) ((void)opt, ZSTD_bitWeight(stat)) -#elif 0 /* fractional bit accuracy */ -# define BITCOST_ACCURACY 8 -# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY) -# define WEIGHT(stat,opt) ((void)opt, ZSTD_fracWeight(stat)) -#else /* opt==approx, ultra==accurate */ -# define BITCOST_ACCURACY 8 -# define BITCOST_MULTIPLIER (1 << BITCOST_ACCURACY) -# define WEIGHT(stat,opt) (opt ? ZSTD_fracWeight(stat) : ZSTD_bitWeight(stat)) -#endif - -MEM_STATIC U32 ZSTD_bitWeight(U32 stat) -{ - return (ZSTD_highbit32(stat+1) * BITCOST_MULTIPLIER); -} - -MEM_STATIC U32 ZSTD_fracWeight(U32 rawStat) -{ - U32 const stat = rawStat + 1; - U32 const hb = ZSTD_highbit32(stat); - U32 const BWeight = hb * BITCOST_MULTIPLIER; - U32 const FWeight = (stat << BITCOST_ACCURACY) >> hb; - U32 const weight = BWeight + FWeight; - assert(hb + BITCOST_ACCURACY < 31); - return weight; -} - -#if (DEBUGLEVEL>=2) -/* debugging function, - * @return price in bytes as fractional value - * for debug messages only */ -MEM_STATIC double ZSTD_fCost(U32 price) -{ - return (double)price / (BITCOST_MULTIPLIER*8); -} -#endif - -static int ZSTD_compressedLiterals(optState_t const* const optPtr) -{ - return optPtr->literalCompressionMode != ZSTD_lcm_uncompressed; -} - -static void ZSTD_setBasePrices(optState_t* optPtr, int optLevel) -{ - if (ZSTD_compressedLiterals(optPtr)) - optPtr->litSumBasePrice = WEIGHT(optPtr->litSum, optLevel); - optPtr->litLengthSumBasePrice = WEIGHT(optPtr->litLengthSum, optLevel); - optPtr->matchLengthSumBasePrice = WEIGHT(optPtr->matchLengthSum, optLevel); - optPtr->offCodeSumBasePrice = WEIGHT(optPtr->offCodeSum, optLevel); -} - - -/* ZSTD_downscaleStat() : - * reduce all elements in table by a factor 2^(ZSTD_FREQ_DIV+malus) - * return the resulting sum of elements */ -static U32 ZSTD_downscaleStat(unsigned* table, U32 lastEltIndex, int malus) -{ - U32 s, sum=0; - DEBUGLOG(5, "ZSTD_downscaleStat (nbElts=%u)", (unsigned)lastEltIndex+1); - assert(ZSTD_FREQ_DIV+malus > 0 && ZSTD_FREQ_DIV+malus < 31); - for (s=0; s<lastEltIndex+1; s++) { - table[s] = 1 + (table[s] >> (ZSTD_FREQ_DIV+malus)); - sum += table[s]; - } - return sum; -} - -/* ZSTD_rescaleFreqs() : - * if first block (detected by optPtr->litLengthSum == 0) : init statistics - * take hints from dictionary if there is one - * or init from zero, using src for literals stats, or flat 1 for match symbols - * otherwise downscale existing stats, to be used as seed for next block. - */ -static void -ZSTD_rescaleFreqs(optState_t* const optPtr, - const BYTE* const src, size_t const srcSize, - int const optLevel) -{ - int const compressedLiterals = ZSTD_compressedLiterals(optPtr); - DEBUGLOG(5, "ZSTD_rescaleFreqs (srcSize=%u)", (unsigned)srcSize); - optPtr->priceType = zop_dynamic; - - if (optPtr->litLengthSum == 0) { /* first block : init */ - if (srcSize <= ZSTD_PREDEF_THRESHOLD) { /* heuristic */ - DEBUGLOG(5, "(srcSize <= ZSTD_PREDEF_THRESHOLD) => zop_predef"); - optPtr->priceType = zop_predef; - } - - assert(optPtr->symbolCosts != NULL); - if (optPtr->symbolCosts->huf.repeatMode == HUF_repeat_valid) { - /* huffman table presumed generated by dictionary */ - optPtr->priceType = zop_dynamic; - - if (compressedLiterals) { - unsigned lit; - assert(optPtr->litFreq != NULL); - optPtr->litSum = 0; - for (lit=0; lit<=MaxLit; lit++) { - U32 const scaleLog = 11; /* scale to 2K */ - U32 const bitCost = HUF_getNbBits(optPtr->symbolCosts->huf.CTable, lit); - assert(bitCost <= scaleLog); - optPtr->litFreq[lit] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/; - optPtr->litSum += optPtr->litFreq[lit]; - } } - - { unsigned ll; - FSE_CState_t llstate; - FSE_initCState(&llstate, optPtr->symbolCosts->fse.litlengthCTable); - optPtr->litLengthSum = 0; - for (ll=0; ll<=MaxLL; ll++) { - U32 const scaleLog = 10; /* scale to 1K */ - U32 const bitCost = FSE_getMaxNbBits(llstate.symbolTT, ll); - assert(bitCost < scaleLog); - optPtr->litLengthFreq[ll] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/; - optPtr->litLengthSum += optPtr->litLengthFreq[ll]; - } } - - { unsigned ml; - FSE_CState_t mlstate; - FSE_initCState(&mlstate, optPtr->symbolCosts->fse.matchlengthCTable); - optPtr->matchLengthSum = 0; - for (ml=0; ml<=MaxML; ml++) { - U32 const scaleLog = 10; - U32 const bitCost = FSE_getMaxNbBits(mlstate.symbolTT, ml); - assert(bitCost < scaleLog); - optPtr->matchLengthFreq[ml] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/; - optPtr->matchLengthSum += optPtr->matchLengthFreq[ml]; - } } - - { unsigned of; - FSE_CState_t ofstate; - FSE_initCState(&ofstate, optPtr->symbolCosts->fse.offcodeCTable); - optPtr->offCodeSum = 0; - for (of=0; of<=MaxOff; of++) { - U32 const scaleLog = 10; - U32 const bitCost = FSE_getMaxNbBits(ofstate.symbolTT, of); - assert(bitCost < scaleLog); - optPtr->offCodeFreq[of] = bitCost ? 1 << (scaleLog-bitCost) : 1 /*minimum to calculate cost*/; - optPtr->offCodeSum += optPtr->offCodeFreq[of]; - } } - - } else { /* not a dictionary */ - - assert(optPtr->litFreq != NULL); - if (compressedLiterals) { - unsigned lit = MaxLit; - HIST_count_simple(optPtr->litFreq, &lit, src, srcSize); /* use raw first block to init statistics */ - optPtr->litSum = ZSTD_downscaleStat(optPtr->litFreq, MaxLit, 1); - } - - { unsigned ll; - for (ll=0; ll<=MaxLL; ll++) - optPtr->litLengthFreq[ll] = 1; - } - optPtr->litLengthSum = MaxLL+1; - - { unsigned ml; - for (ml=0; ml<=MaxML; ml++) - optPtr->matchLengthFreq[ml] = 1; - } - optPtr->matchLengthSum = MaxML+1; - - { unsigned of; - for (of=0; of<=MaxOff; of++) - optPtr->offCodeFreq[of] = 1; - } - optPtr->offCodeSum = MaxOff+1; - - } - - } else { /* new block : re-use previous statistics, scaled down */ - - if (compressedLiterals) - optPtr->litSum = ZSTD_downscaleStat(optPtr->litFreq, MaxLit, 1); - optPtr->litLengthSum = ZSTD_downscaleStat(optPtr->litLengthFreq, MaxLL, 0); - optPtr->matchLengthSum = ZSTD_downscaleStat(optPtr->matchLengthFreq, MaxML, 0); - optPtr->offCodeSum = ZSTD_downscaleStat(optPtr->offCodeFreq, MaxOff, 0); - } - - ZSTD_setBasePrices(optPtr, optLevel); -} - -/* ZSTD_rawLiteralsCost() : - * price of literals (only) in specified segment (which length can be 0). - * does not include price of literalLength symbol */ -static U32 ZSTD_rawLiteralsCost(const BYTE* const literals, U32 const litLength, - const optState_t* const optPtr, - int optLevel) -{ - if (litLength == 0) return 0; - - if (!ZSTD_compressedLiterals(optPtr)) - return (litLength << 3) * BITCOST_MULTIPLIER; /* Uncompressed - 8 bytes per literal. */ - - if (optPtr->priceType == zop_predef) - return (litLength*6) * BITCOST_MULTIPLIER; /* 6 bit per literal - no statistic used */ - - /* dynamic statistics */ - { U32 price = litLength * optPtr->litSumBasePrice; - U32 u; - for (u=0; u < litLength; u++) { - assert(WEIGHT(optPtr->litFreq[literals[u]], optLevel) <= optPtr->litSumBasePrice); /* literal cost should never be negative */ - price -= WEIGHT(optPtr->litFreq[literals[u]], optLevel); - } - return price; - } -} - -/* ZSTD_litLengthPrice() : - * cost of literalLength symbol */ -static U32 ZSTD_litLengthPrice(U32 const litLength, const optState_t* const optPtr, int optLevel) -{ - if (optPtr->priceType == zop_predef) return WEIGHT(litLength, optLevel); - - /* dynamic statistics */ - { U32 const llCode = ZSTD_LLcode(litLength); - return (LL_bits[llCode] * BITCOST_MULTIPLIER) - + optPtr->litLengthSumBasePrice - - WEIGHT(optPtr->litLengthFreq[llCode], optLevel); - } -} - -/* ZSTD_litLengthContribution() : - * @return ( cost(litlength) - cost(0) ) - * this value can then be added to rawLiteralsCost() - * to provide a cost which is directly comparable to a match ending at same position */ -static int ZSTD_litLengthContribution(U32 const litLength, const optState_t* const optPtr, int optLevel) -{ - if (optPtr->priceType >= zop_predef) return WEIGHT(litLength, optLevel); - - /* dynamic statistics */ - { U32 const llCode = ZSTD_LLcode(litLength); - int const contribution = (LL_bits[llCode] * BITCOST_MULTIPLIER) - + WEIGHT(optPtr->litLengthFreq[0], optLevel) /* note: log2litLengthSum cancel out */ - - WEIGHT(optPtr->litLengthFreq[llCode], optLevel); -#if 1 - return contribution; -#else - return MAX(0, contribution); /* sometimes better, sometimes not ... */ -#endif - } -} - -/* ZSTD_literalsContribution() : - * creates a fake cost for the literals part of a sequence - * which can be compared to the ending cost of a match - * should a new match start at this position */ -static int ZSTD_literalsContribution(const BYTE* const literals, U32 const litLength, - const optState_t* const optPtr, - int optLevel) -{ - int const contribution = ZSTD_rawLiteralsCost(literals, litLength, optPtr, optLevel) - + ZSTD_litLengthContribution(litLength, optPtr, optLevel); - return contribution; -} - -/* ZSTD_getMatchPrice() : - * Provides the cost of the match part (offset + matchLength) of a sequence - * Must be combined with ZSTD_fullLiteralsCost() to get the full cost of a sequence. - * optLevel: when <2, favors small offset for decompression speed (improved cache efficiency) */ -FORCE_INLINE_TEMPLATE U32 -ZSTD_getMatchPrice(U32 const offset, - U32 const matchLength, - const optState_t* const optPtr, - int const optLevel) -{ - U32 price; - U32 const offCode = ZSTD_highbit32(offset+1); - U32 const mlBase = matchLength - MINMATCH; - assert(matchLength >= MINMATCH); - - if (optPtr->priceType == zop_predef) /* fixed scheme, do not use statistics */ - return WEIGHT(mlBase, optLevel) + ((16 + offCode) * BITCOST_MULTIPLIER); - - /* dynamic statistics */ - price = (offCode * BITCOST_MULTIPLIER) + (optPtr->offCodeSumBasePrice - WEIGHT(optPtr->offCodeFreq[offCode], optLevel)); - if ((optLevel<2) /*static*/ && offCode >= 20) - price += (offCode-19)*2 * BITCOST_MULTIPLIER; /* handicap for long distance offsets, favor decompression speed */ - - /* match Length */ - { U32 const mlCode = ZSTD_MLcode(mlBase); - price += (ML_bits[mlCode] * BITCOST_MULTIPLIER) + (optPtr->matchLengthSumBasePrice - WEIGHT(optPtr->matchLengthFreq[mlCode], optLevel)); - } - - price += BITCOST_MULTIPLIER / 5; /* heuristic : make matches a bit more costly to favor less sequences -> faster decompression speed */ - - DEBUGLOG(8, "ZSTD_getMatchPrice(ml:%u) = %u", matchLength, price); - return price; -} - -/* ZSTD_updateStats() : - * assumption : literals + litLengtn <= iend */ -static void ZSTD_updateStats(optState_t* const optPtr, - U32 litLength, const BYTE* literals, - U32 offsetCode, U32 matchLength) -{ - /* literals */ - if (ZSTD_compressedLiterals(optPtr)) { - U32 u; - for (u=0; u < litLength; u++) - optPtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD; - optPtr->litSum += litLength*ZSTD_LITFREQ_ADD; - } - - /* literal Length */ - { U32 const llCode = ZSTD_LLcode(litLength); - optPtr->litLengthFreq[llCode]++; - optPtr->litLengthSum++; - } - - /* match offset code (0-2=>repCode; 3+=>offset+2) */ - { U32 const offCode = ZSTD_highbit32(offsetCode+1); - assert(offCode <= MaxOff); - optPtr->offCodeFreq[offCode]++; - optPtr->offCodeSum++; - } - - /* match Length */ - { U32 const mlBase = matchLength - MINMATCH; - U32 const mlCode = ZSTD_MLcode(mlBase); - optPtr->matchLengthFreq[mlCode]++; - optPtr->matchLengthSum++; - } -} - - -/* ZSTD_readMINMATCH() : - * function safe only for comparisons - * assumption : memPtr must be at least 4 bytes before end of buffer */ -MEM_STATIC U32 ZSTD_readMINMATCH(const void* memPtr, U32 length) -{ - switch (length) - { - default : - case 4 : return MEM_read32(memPtr); - case 3 : if (MEM_isLittleEndian()) - return MEM_read32(memPtr)<<8; - else - return MEM_read32(memPtr)>>8; - } -} - - -/* Update hashTable3 up to ip (excluded) - Assumption : always within prefix (i.e. not within extDict) */ -static U32 ZSTD_insertAndFindFirstIndexHash3 (ZSTD_matchState_t* ms, const BYTE* const ip) -{ - U32* const hashTable3 = ms->hashTable3; - U32 const hashLog3 = ms->hashLog3; - const BYTE* const base = ms->window.base; - U32 idx = ms->nextToUpdate3; - U32 const target = ms->nextToUpdate3 = (U32)(ip - base); - size_t const hash3 = ZSTD_hash3Ptr(ip, hashLog3); - assert(hashLog3 > 0); - - while(idx < target) { - hashTable3[ZSTD_hash3Ptr(base+idx, hashLog3)] = idx; - idx++; - } - - return hashTable3[hash3]; -} - - -/*-************************************* -* Binary Tree search -***************************************/ -/** ZSTD_insertBt1() : add one or multiple positions to tree. - * ip : assumed <= iend-8 . - * @return : nb of positions added */ -static U32 ZSTD_insertBt1( - ZSTD_matchState_t* ms, - const BYTE* const ip, const BYTE* const iend, - U32 const mls, const int extDict) -{ - const ZSTD_compressionParameters* const cParams = &ms->cParams; - U32* const hashTable = ms->hashTable; - U32 const hashLog = cParams->hashLog; - size_t const h = ZSTD_hashPtr(ip, hashLog, mls); - U32* const bt = ms->chainTable; - U32 const btLog = cParams->chainLog - 1; - U32 const btMask = (1 << btLog) - 1; - U32 matchIndex = hashTable[h]; - size_t commonLengthSmaller=0, commonLengthLarger=0; - const BYTE* const base = ms->window.base; - const BYTE* const dictBase = ms->window.dictBase; - const U32 dictLimit = ms->window.dictLimit; - const BYTE* const dictEnd = dictBase + dictLimit; - const BYTE* const prefixStart = base + dictLimit; - const BYTE* match; - const U32 current = (U32)(ip-base); - const U32 btLow = btMask >= current ? 0 : current - btMask; - U32* smallerPtr = bt + 2*(current&btMask); - U32* largerPtr = smallerPtr + 1; - U32 dummy32; /* to be nullified at the end */ - U32 const windowLow = ms->window.lowLimit; - U32 matchEndIdx = current+8+1; - size_t bestLength = 8; - U32 nbCompares = 1U << cParams->searchLog; -#ifdef ZSTD_C_PREDICT - U32 predictedSmall = *(bt + 2*((current-1)&btMask) + 0); - U32 predictedLarge = *(bt + 2*((current-1)&btMask) + 1); - predictedSmall += (predictedSmall>0); - predictedLarge += (predictedLarge>0); -#endif /* ZSTD_C_PREDICT */ - - DEBUGLOG(8, "ZSTD_insertBt1 (%u)", current); - - assert(ip <= iend-8); /* required for h calculation */ - hashTable[h] = current; /* Update Hash Table */ - - assert(windowLow > 0); - while (nbCompares-- && (matchIndex >= windowLow)) { - U32* const nextPtr = bt + 2*(matchIndex & btMask); - size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ - assert(matchIndex < current); - -#ifdef ZSTD_C_PREDICT /* note : can create issues when hlog small <= 11 */ - const U32* predictPtr = bt + 2*((matchIndex-1) & btMask); /* written this way, as bt is a roll buffer */ - if (matchIndex == predictedSmall) { - /* no need to check length, result known */ - *smallerPtr = matchIndex; - if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */ - smallerPtr = nextPtr+1; /* new "smaller" => larger of match */ - matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */ - predictedSmall = predictPtr[1] + (predictPtr[1]>0); - continue; - } - if (matchIndex == predictedLarge) { - *largerPtr = matchIndex; - if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */ - largerPtr = nextPtr; - matchIndex = nextPtr[0]; - predictedLarge = predictPtr[0] + (predictPtr[0]>0); - continue; - } -#endif - - if (!extDict || (matchIndex+matchLength >= dictLimit)) { - assert(matchIndex+matchLength >= dictLimit); /* might be wrong if actually extDict */ - match = base + matchIndex; - matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend); - } else { - match = dictBase + matchIndex; - matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart); - if (matchIndex+matchLength >= dictLimit) - match = base + matchIndex; /* to prepare for next usage of match[matchLength] */ - } - - if (matchLength > bestLength) { - bestLength = matchLength; - if (matchLength > matchEndIdx - matchIndex) - matchEndIdx = matchIndex + (U32)matchLength; - } - - if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */ - break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */ - } - - if (match[matchLength] < ip[matchLength]) { /* necessarily within buffer */ - /* match is smaller than current */ - *smallerPtr = matchIndex; /* update smaller idx */ - commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */ - if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop searching */ - smallerPtr = nextPtr+1; /* new "candidate" => larger than match, which was smaller than target */ - matchIndex = nextPtr[1]; /* new matchIndex, larger than previous and closer to current */ - } else { - /* match is larger than current */ - *largerPtr = matchIndex; - commonLengthLarger = matchLength; - if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop searching */ - largerPtr = nextPtr; - matchIndex = nextPtr[0]; - } } - - *smallerPtr = *largerPtr = 0; - if (bestLength > 384) return MIN(192, (U32)(bestLength - 384)); /* speed optimization */ - assert(matchEndIdx > current + 8); - return matchEndIdx - (current + 8); -} - -FORCE_INLINE_TEMPLATE -void ZSTD_updateTree_internal( - ZSTD_matchState_t* ms, - const BYTE* const ip, const BYTE* const iend, - const U32 mls, const ZSTD_dictMode_e dictMode) -{ - const BYTE* const base = ms->window.base; - U32 const target = (U32)(ip - base); - U32 idx = ms->nextToUpdate; - DEBUGLOG(6, "ZSTD_updateTree_internal, from %u to %u (dictMode:%u)", - idx, target, dictMode); - - while(idx < target) - idx += ZSTD_insertBt1(ms, base+idx, iend, mls, dictMode == ZSTD_extDict); - ms->nextToUpdate = target; -} - -void ZSTD_updateTree(ZSTD_matchState_t* ms, const BYTE* ip, const BYTE* iend) { - ZSTD_updateTree_internal(ms, ip, iend, ms->cParams.minMatch, ZSTD_noDict); -} - -FORCE_INLINE_TEMPLATE -U32 ZSTD_insertBtAndGetAllMatches ( - ZSTD_matchState_t* ms, - const BYTE* const ip, const BYTE* const iLimit, const ZSTD_dictMode_e dictMode, - U32 rep[ZSTD_REP_NUM], - U32 const ll0, /* tells if associated literal length is 0 or not. This value must be 0 or 1 */ - ZSTD_match_t* matches, - const U32 lengthToBeat, - U32 const mls /* template */) -{ - const ZSTD_compressionParameters* const cParams = &ms->cParams; - U32 const sufficient_len = MIN(cParams->targetLength, ZSTD_OPT_NUM -1); - const BYTE* const base = ms->window.base; - U32 const current = (U32)(ip-base); - U32 const hashLog = cParams->hashLog; - U32 const minMatch = (mls==3) ? 3 : 4; - U32* const hashTable = ms->hashTable; - size_t const h = ZSTD_hashPtr(ip, hashLog, mls); - U32 matchIndex = hashTable[h]; - U32* const bt = ms->chainTable; - U32 const btLog = cParams->chainLog - 1; - U32 const btMask= (1U << btLog) - 1; - size_t commonLengthSmaller=0, commonLengthLarger=0; - const BYTE* const dictBase = ms->window.dictBase; - U32 const dictLimit = ms->window.dictLimit; - const BYTE* const dictEnd = dictBase + dictLimit; - const BYTE* const prefixStart = base + dictLimit; - U32 const btLow = btMask >= current ? 0 : current - btMask; - U32 const windowLow = ms->window.lowLimit; - U32 const matchLow = windowLow ? windowLow : 1; - U32* smallerPtr = bt + 2*(current&btMask); - U32* largerPtr = bt + 2*(current&btMask) + 1; - U32 matchEndIdx = current+8+1; /* farthest referenced position of any match => detects repetitive patterns */ - U32 dummy32; /* to be nullified at the end */ - U32 mnum = 0; - U32 nbCompares = 1U << cParams->searchLog; - - const ZSTD_matchState_t* dms = dictMode == ZSTD_dictMatchState ? ms->dictMatchState : NULL; - const ZSTD_compressionParameters* const dmsCParams = - dictMode == ZSTD_dictMatchState ? &dms->cParams : NULL; - const BYTE* const dmsBase = dictMode == ZSTD_dictMatchState ? dms->window.base : NULL; - const BYTE* const dmsEnd = dictMode == ZSTD_dictMatchState ? dms->window.nextSrc : NULL; - U32 const dmsHighLimit = dictMode == ZSTD_dictMatchState ? (U32)(dmsEnd - dmsBase) : 0; - U32 const dmsLowLimit = dictMode == ZSTD_dictMatchState ? dms->window.lowLimit : 0; - U32 const dmsIndexDelta = dictMode == ZSTD_dictMatchState ? windowLow - dmsHighLimit : 0; - U32 const dmsHashLog = dictMode == ZSTD_dictMatchState ? dmsCParams->hashLog : hashLog; - U32 const dmsBtLog = dictMode == ZSTD_dictMatchState ? dmsCParams->chainLog - 1 : btLog; - U32 const dmsBtMask = dictMode == ZSTD_dictMatchState ? (1U << dmsBtLog) - 1 : 0; - U32 const dmsBtLow = dictMode == ZSTD_dictMatchState && dmsBtMask < dmsHighLimit - dmsLowLimit ? dmsHighLimit - dmsBtMask : dmsLowLimit; - - size_t bestLength = lengthToBeat-1; - DEBUGLOG(8, "ZSTD_insertBtAndGetAllMatches: current=%u", current); - - /* check repCode */ - assert(ll0 <= 1); /* necessarily 1 or 0 */ - { U32 const lastR = ZSTD_REP_NUM + ll0; - U32 repCode; - for (repCode = ll0; repCode < lastR; repCode++) { - U32 const repOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode]; - U32 const repIndex = current - repOffset; - U32 repLen = 0; - assert(current >= dictLimit); - if (repOffset-1 /* intentional overflow, discards 0 and -1 */ < current-dictLimit) { /* equivalent to `current > repIndex >= dictLimit` */ - if (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repOffset, minMatch)) { - repLen = (U32)ZSTD_count(ip+minMatch, ip+minMatch-repOffset, iLimit) + minMatch; - } - } else { /* repIndex < dictLimit || repIndex >= current */ - const BYTE* const repMatch = dictMode == ZSTD_dictMatchState ? - dmsBase + repIndex - dmsIndexDelta : - dictBase + repIndex; - assert(current >= windowLow); - if ( dictMode == ZSTD_extDict - && ( ((repOffset-1) /*intentional overflow*/ < current - windowLow) /* equivalent to `current > repIndex >= windowLow` */ - & (((U32)((dictLimit-1) - repIndex) >= 3) ) /* intentional overflow : do not test positions overlapping 2 memory segments */) - && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) { - repLen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iLimit, dictEnd, prefixStart) + minMatch; - } - if (dictMode == ZSTD_dictMatchState - && ( ((repOffset-1) /*intentional overflow*/ < current - (dmsLowLimit + dmsIndexDelta)) /* equivalent to `current > repIndex >= dmsLowLimit` */ - & ((U32)((dictLimit-1) - repIndex) >= 3) ) /* intentional overflow : do not test positions overlapping 2 memory segments */ - && (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(repMatch, minMatch)) ) { - repLen = (U32)ZSTD_count_2segments(ip+minMatch, repMatch+minMatch, iLimit, dmsEnd, prefixStart) + minMatch; - } } - /* save longer solution */ - if (repLen > bestLength) { - DEBUGLOG(8, "found repCode %u (ll0:%u, offset:%u) of length %u", - repCode, ll0, repOffset, repLen); - bestLength = repLen; - matches[mnum].off = repCode - ll0; - matches[mnum].len = (U32)repLen; - mnum++; - if ( (repLen > sufficient_len) - | (ip+repLen == iLimit) ) { /* best possible */ - return mnum; - } } } } - - /* HC3 match finder */ - if ((mls == 3) /*static*/ && (bestLength < mls)) { - U32 const matchIndex3 = ZSTD_insertAndFindFirstIndexHash3(ms, ip); - if ((matchIndex3 >= matchLow) - & (current - matchIndex3 < (1<<18)) /*heuristic : longer distance likely too expensive*/ ) { - size_t mlen; - if ((dictMode == ZSTD_noDict) /*static*/ || (dictMode == ZSTD_dictMatchState) /*static*/ || (matchIndex3 >= dictLimit)) { - const BYTE* const match = base + matchIndex3; - mlen = ZSTD_count(ip, match, iLimit); - } else { - const BYTE* const match = dictBase + matchIndex3; - mlen = ZSTD_count_2segments(ip, match, iLimit, dictEnd, prefixStart); - } - - /* save best solution */ - if (mlen >= mls /* == 3 > bestLength */) { - DEBUGLOG(8, "found small match with hlog3, of length %u", - (U32)mlen); - bestLength = mlen; - assert(current > matchIndex3); - assert(mnum==0); /* no prior solution */ - matches[0].off = (current - matchIndex3) + ZSTD_REP_MOVE; - matches[0].len = (U32)mlen; - mnum = 1; - if ( (mlen > sufficient_len) | - (ip+mlen == iLimit) ) { /* best possible length */ - ms->nextToUpdate = current+1; /* skip insertion */ - return 1; - } - } - } - /* no dictMatchState lookup: dicts don't have a populated HC3 table */ - } - - hashTable[h] = current; /* Update Hash Table */ - - while (nbCompares-- && (matchIndex >= matchLow)) { - U32* const nextPtr = bt + 2*(matchIndex & btMask); - size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ - const BYTE* match; - assert(current > matchIndex); - - if ((dictMode == ZSTD_noDict) || (dictMode == ZSTD_dictMatchState) || (matchIndex+matchLength >= dictLimit)) { - assert(matchIndex+matchLength >= dictLimit); /* ensure the condition is correct when !extDict */ - match = base + matchIndex; - matchLength += ZSTD_count(ip+matchLength, match+matchLength, iLimit); - } else { - match = dictBase + matchIndex; - matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dictEnd, prefixStart); - if (matchIndex+matchLength >= dictLimit) - match = base + matchIndex; /* prepare for match[matchLength] */ - } - - if (matchLength > bestLength) { - DEBUGLOG(8, "found match of length %u at distance %u (offCode=%u)", - (U32)matchLength, current - matchIndex, current - matchIndex + ZSTD_REP_MOVE); - assert(matchEndIdx > matchIndex); - if (matchLength > matchEndIdx - matchIndex) - matchEndIdx = matchIndex + (U32)matchLength; - bestLength = matchLength; - matches[mnum].off = (current - matchIndex) + ZSTD_REP_MOVE; - matches[mnum].len = (U32)matchLength; - mnum++; - if ( (matchLength > ZSTD_OPT_NUM) - | (ip+matchLength == iLimit) /* equal : no way to know if inf or sup */) { - if (dictMode == ZSTD_dictMatchState) nbCompares = 0; /* break should also skip searching dms */ - break; /* drop, to preserve bt consistency (miss a little bit of compression) */ - } - } - - if (match[matchLength] < ip[matchLength]) { - /* match smaller than current */ - *smallerPtr = matchIndex; /* update smaller idx */ - commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */ - if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */ - smallerPtr = nextPtr+1; /* new candidate => larger than match, which was smaller than current */ - matchIndex = nextPtr[1]; /* new matchIndex, larger than previous, closer to current */ - } else { - *largerPtr = matchIndex; - commonLengthLarger = matchLength; - if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */ - largerPtr = nextPtr; - matchIndex = nextPtr[0]; - } } - - *smallerPtr = *largerPtr = 0; - - if (dictMode == ZSTD_dictMatchState && nbCompares) { - size_t const dmsH = ZSTD_hashPtr(ip, dmsHashLog, mls); - U32 dictMatchIndex = dms->hashTable[dmsH]; - const U32* const dmsBt = dms->chainTable; - commonLengthSmaller = commonLengthLarger = 0; - while (nbCompares-- && (dictMatchIndex > dmsLowLimit)) { - const U32* const nextPtr = dmsBt + 2*(dictMatchIndex & dmsBtMask); - size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ - const BYTE* match = dmsBase + dictMatchIndex; - matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dmsEnd, prefixStart); - if (dictMatchIndex+matchLength >= dmsHighLimit) - match = base + dictMatchIndex + dmsIndexDelta; /* to prepare for next usage of match[matchLength] */ - - if (matchLength > bestLength) { - matchIndex = dictMatchIndex + dmsIndexDelta; - DEBUGLOG(8, "found dms match of length %u at distance %u (offCode=%u)", - (U32)matchLength, current - matchIndex, current - matchIndex + ZSTD_REP_MOVE); - if (matchLength > matchEndIdx - matchIndex) - matchEndIdx = matchIndex + (U32)matchLength; - bestLength = matchLength; - matches[mnum].off = (current - matchIndex) + ZSTD_REP_MOVE; - matches[mnum].len = (U32)matchLength; - mnum++; - if ( (matchLength > ZSTD_OPT_NUM) - | (ip+matchLength == iLimit) /* equal : no way to know if inf or sup */) { - break; /* drop, to guarantee consistency (miss a little bit of compression) */ - } - } - - if (dictMatchIndex <= dmsBtLow) { break; } /* beyond tree size, stop the search */ - if (match[matchLength] < ip[matchLength]) { - commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */ - dictMatchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */ - } else { - /* match is larger than current */ - commonLengthLarger = matchLength; - dictMatchIndex = nextPtr[0]; - } - } - } - - assert(matchEndIdx > current+8); - ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */ - return mnum; -} - - -FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches ( - ZSTD_matchState_t* ms, - const BYTE* ip, const BYTE* const iHighLimit, const ZSTD_dictMode_e dictMode, - U32 rep[ZSTD_REP_NUM], U32 const ll0, - ZSTD_match_t* matches, U32 const lengthToBeat) -{ - const ZSTD_compressionParameters* const cParams = &ms->cParams; - U32 const matchLengthSearch = cParams->minMatch; - DEBUGLOG(8, "ZSTD_BtGetAllMatches"); - if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */ - ZSTD_updateTree_internal(ms, ip, iHighLimit, matchLengthSearch, dictMode); - switch(matchLengthSearch) - { - case 3 : return ZSTD_insertBtAndGetAllMatches(ms, ip, iHighLimit, dictMode, rep, ll0, matches, lengthToBeat, 3); - default : - case 4 : return ZSTD_insertBtAndGetAllMatches(ms, ip, iHighLimit, dictMode, rep, ll0, matches, lengthToBeat, 4); - case 5 : return ZSTD_insertBtAndGetAllMatches(ms, ip, iHighLimit, dictMode, rep, ll0, matches, lengthToBeat, 5); - case 7 : - case 6 : return ZSTD_insertBtAndGetAllMatches(ms, ip, iHighLimit, dictMode, rep, ll0, matches, lengthToBeat, 6); - } -} - - -/*-******************************* -* Optimal parser -*********************************/ -typedef struct repcodes_s { - U32 rep[3]; -} repcodes_t; - -static 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; -} - - -static U32 ZSTD_totalLen(ZSTD_optimal_t sol) -{ - return sol.litlen + sol.mlen; -} - -#if 0 /* debug */ - -static void -listStats(const U32* table, int lastEltID) -{ - int const nbElts = lastEltID + 1; - int enb; - for (enb=0; enb < nbElts; enb++) { - (void)table; - //RAWLOG(2, "%3i:%3i, ", enb, table[enb]); - RAWLOG(2, "%4i,", table[enb]); - } - RAWLOG(2, " \n"); -} - -#endif - -FORCE_INLINE_TEMPLATE size_t -ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms, - seqStore_t* seqStore, - U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize, - const int optLevel, - const ZSTD_dictMode_e dictMode) -{ - optState_t* const optStatePtr = &ms->opt; - 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 = ms->window.base; - const BYTE* const prefixStart = base + ms->window.dictLimit; - const ZSTD_compressionParameters* const cParams = &ms->cParams; - - U32 const sufficient_len = MIN(cParams->targetLength, ZSTD_OPT_NUM -1); - U32 const minMatch = (cParams->minMatch == 3) ? 3 : 4; - - ZSTD_optimal_t* const opt = optStatePtr->priceTable; - ZSTD_match_t* const matches = optStatePtr->matchTable; - ZSTD_optimal_t lastSequence; - - /* init */ - DEBUGLOG(5, "ZSTD_compressBlock_opt_generic: current=%u, prefix=%u, nextToUpdate=%u", - (U32)(ip - base), ms->window.dictLimit, ms->nextToUpdate); - assert(optLevel <= 2); - ms->nextToUpdate3 = ms->nextToUpdate; - ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize, optLevel); - ip += (ip==prefixStart); - - /* Match Loop */ - while (ip < ilimit) { - U32 cur, last_pos = 0; - - /* find first match */ - { U32 const litlen = (U32)(ip - anchor); - U32 const ll0 = !litlen; - U32 const nbMatches = ZSTD_BtGetAllMatches(ms, ip, iend, dictMode, 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 = 0; /* means is_a_literal */ - opt[0].litlen = litlen; - opt[0].price = ZSTD_literalsContribution(anchor, litlen, optStatePtr, optLevel); - - /* large match -> immediate encoding */ - { U32 const maxML = matches[nbMatches-1].len; - U32 const maxOffset = matches[nbMatches-1].off; - DEBUGLOG(6, "found %u matches of maxLength=%u and maxOffCode=%u at cPos=%u => start new series", - nbMatches, maxML, maxOffset, (U32)(ip-prefixStart)); - - if (maxML > sufficient_len) { - lastSequence.litlen = litlen; - lastSequence.mlen = maxML; - lastSequence.off = maxOffset; - DEBUGLOG(6, "large match (%u>%u), immediate encoding", - maxML, sufficient_len); - cur = 0; - last_pos = ZSTD_totalLen(lastSequence); - goto _shortestPath; - } } - - /* set prices for first matches starting position == 0 */ - { U32 const literalsPrice = opt[0].price + ZSTD_litLengthPrice(0, optStatePtr, optLevel); - U32 pos; - U32 matchNb; - for (pos = 1; pos < minMatch; pos++) { - opt[pos].price = ZSTD_MAX_PRICE; /* mlen, litlen and price will be fixed during forward scanning */ - } - 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_getMatchPrice(offset, pos, optStatePtr, optLevel); - U32 const sequencePrice = literalsPrice + matchPrice; - DEBUGLOG(7, "rPos:%u => set initial price : %.2f", - pos, ZSTD_fCost(sequencePrice)); - opt[pos].mlen = pos; - opt[pos].off = offset; - opt[pos].litlen = litlen; - opt[pos].price = sequencePrice; - ZSTD_STATIC_ASSERT(sizeof(opt[pos].rep) == sizeof(repHistory)); - memcpy(opt[pos].rep, &repHistory, sizeof(repHistory)); - } } - last_pos = pos-1; - } - } - - /* check further positions */ - for (cur = 1; cur <= last_pos; cur++) { - const BYTE* const inr = ip + cur; - assert(cur < ZSTD_OPT_NUM); - DEBUGLOG(7, "cPos:%zi==rPos:%u", inr-istart, cur) - - /* Fix current position with one literal if cheaper */ - { U32 const litlen = (opt[cur-1].mlen == 0) ? opt[cur-1].litlen + 1 : 1; - int const price = opt[cur-1].price - + ZSTD_rawLiteralsCost(ip+cur-1, 1, optStatePtr, optLevel) - + ZSTD_litLengthPrice(litlen, optStatePtr, optLevel) - - ZSTD_litLengthPrice(litlen-1, optStatePtr, optLevel); - assert(price < 1000000000); /* overflow check */ - if (price <= opt[cur].price) { - DEBUGLOG(7, "cPos:%zi==rPos:%u : better price (%.2f<=%.2f) using literal (ll==%u) (hist:%u,%u,%u)", - inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price), litlen, - opt[cur-1].rep[0], opt[cur-1].rep[1], opt[cur-1].rep[2]); - opt[cur].mlen = 0; - opt[cur].off = 0; - opt[cur].litlen = litlen; - opt[cur].price = price; - memcpy(opt[cur].rep, opt[cur-1].rep, sizeof(opt[cur].rep)); - } else { - DEBUGLOG(7, "cPos:%zi==rPos:%u : literal would cost more (%.2f>%.2f) (hist:%u,%u,%u)", - inr-istart, cur, ZSTD_fCost(price), ZSTD_fCost(opt[cur].price), - opt[cur].rep[0], opt[cur].rep[1], opt[cur].rep[2]); - } - } - - /* 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_test*/ - && (opt[cur+1].price <= opt[cur].price + (BITCOST_MULTIPLIER/2)) ) { - DEBUGLOG(7, "move to next rPos:%u : price is <=", cur+1); - continue; /* skip unpromising positions; about ~+6% speed, -0.01 ratio */ - } - - { U32 const ll0 = (opt[cur].mlen != 0); - U32 const litlen = (opt[cur].mlen == 0) ? opt[cur].litlen : 0; - U32 const previousPrice = opt[cur].price; - U32 const basePrice = previousPrice + ZSTD_litLengthPrice(0, optStatePtr, optLevel); - U32 const nbMatches = ZSTD_BtGetAllMatches(ms, inr, iend, dictMode, opt[cur].rep, ll0, matches, minMatch); - U32 matchNb; - if (!nbMatches) { - DEBUGLOG(7, "rPos:%u : no match found", cur); - continue; - } - - { U32 const maxML = matches[nbMatches-1].len; - DEBUGLOG(7, "cPos:%zi==rPos:%u, found %u matches, of maxLength=%u", - inr-istart, cur, nbMatches, maxML); - - if ( (maxML > sufficient_len) - || (cur + maxML >= ZSTD_OPT_NUM) ) { - lastSequence.mlen = maxML; - lastSequence.off = matches[nbMatches-1].off; - lastSequence.litlen = litlen; - cur -= (opt[cur].mlen==0) ? opt[cur].litlen : 0; /* last sequence is actually only literals, fix cur to last match - note : may underflow, in which case, it's first sequence, and it's okay */ - last_pos = cur + ZSTD_totalLen(lastSequence); - if (cur > ZSTD_OPT_NUM) cur = 0; /* underflow => first match */ - 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=%4u, mlen=%2u, llen=%2u", - matchNb, matches[matchNb].off, lastML, litlen); - - for (mlen = lastML; mlen >= startML; mlen--) { /* scan downward */ - U32 const pos = cur + mlen; - int const price = basePrice + ZSTD_getMatchPrice(offset, mlen, optStatePtr, optLevel); - - if ((pos > last_pos) || (price < opt[pos].price)) { - DEBUGLOG(7, "rPos:%u (ml=%2u) => new better price (%.2f<%.2f)", - pos, mlen, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price)); - while (last_pos < pos) { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; } /* fill empty positions */ - opt[pos].mlen = mlen; - opt[pos].off = offset; - opt[pos].litlen = litlen; - opt[pos].price = price; - ZSTD_STATIC_ASSERT(sizeof(opt[pos].rep) == sizeof(repHistory)); - memcpy(opt[pos].rep, &repHistory, sizeof(repHistory)); - } else { - DEBUGLOG(7, "rPos:%u (ml=%2u) => new price is worse (%.2f>=%.2f)", - pos, mlen, ZSTD_fCost(price), ZSTD_fCost(opt[pos].price)); - if (optLevel==0) break; /* early update abort; gets ~+10% speed for about -0.01 ratio loss */ - } - } } } - } /* for (cur = 1; cur <= last_pos; cur++) */ - - lastSequence = opt[last_pos]; - cur = last_pos > ZSTD_totalLen(lastSequence) ? last_pos - ZSTD_totalLen(lastSequence) : 0; /* single sequence, and it starts before `ip` */ - assert(cur < ZSTD_OPT_NUM); /* control overflow*/ - -_shortestPath: /* cur, last_pos, best_mlen, best_off have to be set */ - assert(opt[0].mlen == 0); - - { U32 const storeEnd = cur + 1; - U32 storeStart = storeEnd; - U32 seqPos = cur; - - DEBUGLOG(6, "start reverse traversal (last_pos:%u, cur:%u)", - last_pos, cur); (void)last_pos; - assert(storeEnd < ZSTD_OPT_NUM); - DEBUGLOG(6, "last sequence copied into pos=%u (llen=%u,mlen=%u,ofc=%u)", - storeEnd, lastSequence.litlen, lastSequence.mlen, lastSequence.off); - opt[storeEnd] = lastSequence; - while (seqPos > 0) { - U32 const backDist = ZSTD_totalLen(opt[seqPos]); - storeStart--; - DEBUGLOG(6, "sequence from rPos=%u copied into pos=%u (llen=%u,mlen=%u,ofc=%u)", - seqPos, storeStart, opt[seqPos].litlen, opt[seqPos].mlen, opt[seqPos].off); - opt[storeStart] = opt[seqPos]; - seqPos = (seqPos > backDist) ? seqPos - backDist : 0; - } - - /* save sequences */ - DEBUGLOG(6, "sending selected sequences into seqStore") - { U32 storePos; - for (storePos=storeStart; storePos <= storeEnd; storePos++) { - U32 const llen = opt[storePos].litlen; - U32 const mlen = opt[storePos].mlen; - U32 const offCode = opt[storePos].off; - U32 const advance = llen + mlen; - DEBUGLOG(6, "considering seq starting at %zi, llen=%u, mlen=%u", - anchor - istart, (unsigned)llen, (unsigned)mlen); - - if (mlen==0) { /* only literals => must be last "sequence", actually starting a new stream of sequences */ - assert(storePos == storeEnd); /* must be last sequence */ - ip = anchor + llen; /* last "sequence" is a bunch of literals => don't progress anchor */ - continue; /* will finish */ - } - - /* repcodes update : like ZSTD_updateRep(), but update in place */ - if (offCode >= ZSTD_REP_NUM) { /* full offset */ - rep[2] = rep[1]; - rep[1] = rep[0]; - rep[0] = offCode - ZSTD_REP_MOVE; - } else { /* repcode */ - U32 const repCode = offCode + (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; - } } - - assert(anchor + llen <= iend); - ZSTD_updateStats(optStatePtr, llen, anchor, offCode, mlen); - ZSTD_storeSeq(seqStore, llen, anchor, offCode, mlen-MINMATCH); - anchor += advance; - ip = anchor; - } } - ZSTD_setBasePrices(optStatePtr, optLevel); - } - - } /* while (ip < ilimit) */ - - /* Return the last literals size */ - return iend - anchor; -} - - -size_t ZSTD_compressBlock_btopt( - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - DEBUGLOG(5, "ZSTD_compressBlock_btopt"); - return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 0 /*optLevel*/, ZSTD_noDict); -} - - -/* used in 2-pass strategy */ -static U32 ZSTD_upscaleStat(unsigned* table, U32 lastEltIndex, int bonus) -{ - U32 s, sum=0; - assert(ZSTD_FREQ_DIV+bonus >= 0); - for (s=0; s<lastEltIndex+1; s++) { - table[s] <<= ZSTD_FREQ_DIV+bonus; - table[s]--; - sum += table[s]; - } - return sum; -} - -/* used in 2-pass strategy */ -MEM_STATIC void ZSTD_upscaleStats(optState_t* optPtr) -{ - if (ZSTD_compressedLiterals(optPtr)) - optPtr->litSum = ZSTD_upscaleStat(optPtr->litFreq, MaxLit, 0); - optPtr->litLengthSum = ZSTD_upscaleStat(optPtr->litLengthFreq, MaxLL, 0); - optPtr->matchLengthSum = ZSTD_upscaleStat(optPtr->matchLengthFreq, MaxML, 0); - optPtr->offCodeSum = ZSTD_upscaleStat(optPtr->offCodeFreq, MaxOff, 0); -} - -/* ZSTD_initStats_ultra(): - * make a first compression pass, just to seed stats with more accurate starting values. - * only works on first block, with no dictionary and no ldm. - * this function cannot error, hence its contract must be respected. - */ -static void -ZSTD_initStats_ultra(ZSTD_matchState_t* ms, - seqStore_t* seqStore, - U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - U32 tmpRep[ZSTD_REP_NUM]; /* updated rep codes will sink here */ - memcpy(tmpRep, rep, sizeof(tmpRep)); - - DEBUGLOG(4, "ZSTD_initStats_ultra (srcSize=%zu)", srcSize); - assert(ms->opt.litLengthSum == 0); /* first block */ - assert(seqStore->sequences == seqStore->sequencesStart); /* no ldm */ - assert(ms->window.dictLimit == ms->window.lowLimit); /* no dictionary */ - assert(ms->window.dictLimit - ms->nextToUpdate <= 1); /* no prefix (note: intentional overflow, defined as 2-complement) */ - - ZSTD_compressBlock_opt_generic(ms, seqStore, tmpRep, src, srcSize, 2 /*optLevel*/, ZSTD_noDict); /* generate stats into ms->opt*/ - - /* invalidate first scan from history */ - ZSTD_resetSeqStore(seqStore); - ms->window.base -= srcSize; - ms->window.dictLimit += (U32)srcSize; - ms->window.lowLimit = ms->window.dictLimit; - ms->nextToUpdate = ms->window.dictLimit; - ms->nextToUpdate3 = ms->window.dictLimit; - - /* re-inforce weight of collected statistics */ - ZSTD_upscaleStats(&ms->opt); -} - -size_t ZSTD_compressBlock_btultra( - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - DEBUGLOG(5, "ZSTD_compressBlock_btultra (srcSize=%zu)", srcSize); - return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_noDict); -} - -size_t ZSTD_compressBlock_btultra2( - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - U32 const current = (U32)((const BYTE*)src - ms->window.base); - DEBUGLOG(5, "ZSTD_compressBlock_btultra2 (srcSize=%zu)", srcSize); - - /* 2-pass strategy: - * this strategy makes a first pass over first block to collect statistics - * and seed next round's statistics with it. - * After 1st pass, function forgets everything, and starts a new block. - * Consequently, this can only work if no data has been previously loaded in tables, - * aka, no dictionary, no prefix, no ldm preprocessing. - * The compression ratio gain is generally small (~0.5% on first block), - * the cost is 2x cpu time on first block. */ - assert(srcSize <= ZSTD_BLOCKSIZE_MAX); - if ( (ms->opt.litLengthSum==0) /* first block */ - && (seqStore->sequences == seqStore->sequencesStart) /* no ldm */ - && (ms->window.dictLimit == ms->window.lowLimit) /* no dictionary */ - && (current == ms->window.dictLimit) /* start of frame, nothing already loaded nor skipped */ - && (srcSize > ZSTD_PREDEF_THRESHOLD) - ) { - ZSTD_initStats_ultra(ms, seqStore, rep, src, srcSize); - } - - return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_noDict); -} - -size_t ZSTD_compressBlock_btopt_dictMatchState( - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 0 /*optLevel*/, ZSTD_dictMatchState); -} - -size_t ZSTD_compressBlock_btultra_dictMatchState( - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_dictMatchState); -} - -size_t ZSTD_compressBlock_btopt_extDict( - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 0 /*optLevel*/, ZSTD_extDict); -} - -size_t ZSTD_compressBlock_btultra_extDict( - ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], - const void* src, size_t srcSize) -{ - return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, src, srcSize, 2 /*optLevel*/, ZSTD_extDict); -} - -/* note : no btultra2 variant for extDict nor dictMatchState, - * because btultra2 is not meant to work with dictionaries - * and is only specific for the first block (no prefix) */ |