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Diffstat (limited to 'lib/zstd/compress/zstd_opt.c')
| -rw-r--r-- | lib/zstd/compress/zstd_opt.c | 1346 |
1 files changed, 1346 insertions, 0 deletions
diff --git a/lib/zstd/compress/zstd_opt.c b/lib/zstd/compress/zstd_opt.c new file mode 100644 index 000000000000..04337050fe9a --- /dev/null +++ b/lib/zstd/compress/zstd_opt.c @@ -0,0 +1,1346 @@ +/* + * Copyright (c) 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_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, + U32* nextToUpdate3, + const BYTE* const ip) +{ + U32* const hashTable3 = ms->hashTable3; + U32 const hashLog3 = ms->hashLog3; + const BYTE* const base = ms->window.base; + U32 idx = *nextToUpdate3; + U32 const target = (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++; + } + + *nextToUpdate3 = target; + 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 curr = (U32)(ip-base); + const U32 btLow = btMask >= curr ? 0 : curr - btMask; + U32* smallerPtr = bt + 2*(curr&btMask); + U32* largerPtr = smallerPtr + 1; + U32 dummy32; /* to be nullified at the end */ + U32 const windowLow = ms->window.lowLimit; + U32 matchEndIdx = curr+8+1; + size_t bestLength = 8; + U32 nbCompares = 1U << cParams->searchLog; +#ifdef ZSTD_C_PREDICT + U32 predictedSmall = *(bt + 2*((curr-1)&btMask) + 0); + U32 predictedLarge = *(bt + 2*((curr-1)&btMask) + 1); + predictedSmall += (predictedSmall>0); + predictedLarge += (predictedLarge>0); +#endif /* ZSTD_C_PREDICT */ + + DEBUGLOG(8, "ZSTD_insertBt1 (%u)", curr); + + assert(ip <= iend-8); /* required for h calculation */ + hashTable[h] = curr; /* Update Hash Table */ + + assert(windowLow > 0); + for (; nbCompares && (matchIndex >= windowLow); --nbCompares) { + U32* const nextPtr = bt + 2*(matchIndex & btMask); + size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ + assert(matchIndex < curr); + +#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; + { U32 positions = 0; + if (bestLength > 384) positions = MIN(192, (U32)(bestLength - 384)); /* speed optimization */ + assert(matchEndIdx > curr + 8); + return MAX(positions, matchEndIdx - (curr + 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) { + U32 const forward = ZSTD_insertBt1(ms, base+idx, iend, mls, dictMode == ZSTD_extDict); + assert(idx < (U32)(idx + forward)); + idx += forward; + } + assert((size_t)(ip - base) <= (size_t)(U32)(-1)); + assert((size_t)(iend - base) <= (size_t)(U32)(-1)); + 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_match_t* matches, /* store result (found matches) in this table (presumed large enough) */ + ZSTD_matchState_t* ms, + U32* nextToUpdate3, + const BYTE* const ip, const BYTE* const iLimit, const ZSTD_dictMode_e dictMode, + const U32 rep[ZSTD_REP_NUM], + U32 const ll0, /* tells if associated literal length is 0 or not. This value must be 0 or 1 */ + 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 curr = (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 >= curr) ? 0 : curr - btMask; + U32 const windowLow = ZSTD_getLowestMatchIndex(ms, curr, cParams->windowLog); + U32 const matchLow = windowLow ? windowLow : 1; + U32* smallerPtr = bt + 2*(curr&btMask); + U32* largerPtr = bt + 2*(curr&btMask) + 1; + U32 matchEndIdx = curr+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", curr); + + /* 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 = curr - repOffset; + U32 repLen = 0; + assert(curr >= dictLimit); + if (repOffset-1 /* intentional overflow, discards 0 and -1 */ < curr-dictLimit) { /* equivalent to `curr > repIndex >= dictLimit` */ + /* We must validate the repcode offset because when we're using a dictionary the + * valid offset range shrinks when the dictionary goes out of bounds. + */ + if ((repIndex >= windowLow) & (ZSTD_readMINMATCH(ip, minMatch) == ZSTD_readMINMATCH(ip - repOffset, minMatch))) { + repLen = (U32)ZSTD_count(ip+minMatch, ip+minMatch-repOffset, iLimit) + minMatch; + } + } else { /* repIndex < dictLimit || repIndex >= curr */ + const BYTE* const repMatch = dictMode == ZSTD_dictMatchState ? + dmsBase + repIndex - dmsIndexDelta : + dictBase + repIndex; + assert(curr >= windowLow); + if ( dictMode == ZSTD_extDict + && ( ((repOffset-1) /*intentional overflow*/ < curr - windowLow) /* equivalent to `curr > 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*/ < curr - (dmsLowLimit + dmsIndexDelta)) /* equivalent to `curr > 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, nextToUpdate3, ip); + if ((matchIndex3 >= matchLow) + & (curr - 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(curr > matchIndex3); + assert(mnum==0); /* no prior solution */ + matches[0].off = (curr - matchIndex3) + ZSTD_REP_MOVE; + matches[0].len = (U32)mlen; + mnum = 1; + if ( (mlen > sufficient_len) | + (ip+mlen == iLimit) ) { /* best possible length */ + ms->nextToUpdate = curr+1; /* skip insertion */ + return 1; + } } } + /* no dictMatchState lookup: dicts don't have a populated HC3 table */ + } + + hashTable[h] = curr; /* Update Hash Table */ + + for (; nbCompares && (matchIndex >= matchLow); --nbCompares) { + U32* const nextPtr = bt + 2*(matchIndex & btMask); + const BYTE* match; + size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ + assert(curr > 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; + if (matchIndex >= dictLimit) assert(memcmp(match, ip, matchLength) == 0); /* ensure early section of match is equal as expected */ + matchLength += ZSTD_count(ip+matchLength, match+matchLength, iLimit); + } else { + match = dictBase + matchIndex; + assert(memcmp(match, ip, matchLength) == 0); /* ensure early section of match is equal as expected */ + matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iLimit, dictEnd, prefixStart); + if (matchIndex+matchLength >= dictLimit) + match = base + matchIndex; /* prepare for match[matchLength] read */ + } + + if (matchLength > bestLength) { + DEBUGLOG(8, "found match of length %u at distance %u (offCode=%u)", + (U32)matchLength, curr - matchIndex, curr - matchIndex + ZSTD_REP_MOVE); + assert(matchEndIdx > matchIndex); + if (matchLength > matchEndIdx - matchIndex) + matchEndIdx = matchIndex + (U32)matchLength; + bestLength = matchLength; + matches[mnum].off = (curr - 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; + + assert(nbCompares <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */ + 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; + for (; nbCompares && (dictMatchIndex > dmsLowLimit); --nbCompares) { + 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, curr - matchIndex, curr - matchIndex + ZSTD_REP_MOVE); + if (matchLength > matchEndIdx - matchIndex) + matchEndIdx = matchIndex + (U32)matchLength; + bestLength = matchLength; + matches[mnum].off = (curr - 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 > curr+8); + ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */ + return mnum; +} + + +FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches ( + ZSTD_match_t* matches, /* store result (match found, increasing size) in this table */ + ZSTD_matchState_t* ms, + U32* nextToUpdate3, + const BYTE* ip, const BYTE* const iHighLimit, const ZSTD_dictMode_e dictMode, + const U32 rep[ZSTD_REP_NUM], + U32 const ll0, + 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(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 3); + default : + case 4 : return ZSTD_insertBtAndGetAllMatches(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 4); + case 5 : return ZSTD_insertBtAndGetAllMatches(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 5); + case 7 : + case 6 : return ZSTD_insertBtAndGetAllMatches(matches, ms, nextToUpdate3, ip, iHighLimit, dictMode, rep, ll0, lengthToBeat, 6); + } +} + +/* *********************** +* LDM helper functions * +*************************/ + +/* Struct containing info needed to make decision about ldm inclusion */ +typedef struct { + rawSeqStore_t seqStore; /* External match candidates store for this block */ + U32 startPosInBlock; /* Start position of the current match candidate */ + U32 endPosInBlock; /* End position of the current match candidate */ + U32 offset; /* Offset of the match candidate */ +} ZSTD_optLdm_t; + +/* ZSTD_optLdm_skipRawSeqStoreBytes(): + * Moves forward in rawSeqStore by nbBytes, which will update the fields 'pos' and 'posInSequence'. + */ +static void ZSTD_optLdm_skipRawSeqStoreBytes(rawSeqStore_t* rawSeqStore, size_t nbBytes) { + U32 currPos = (U32)(rawSeqStore->posInSequence + nbBytes); + while (currPos && rawSeqStore->pos < rawSeqStore->size) { + rawSeq currSeq = rawSeqStore->seq[rawSeqStore->pos]; + if (currPos >= currSeq.litLength + currSeq.matchLength) { + currPos -= currSeq.litLength + currSeq.matchLength; + rawSeqStore->pos++; + } else { + rawSeqStore->posInSequence = currPos; + break; + } + } + if (currPos == 0 || rawSeqStore->pos == rawSeqStore->size) { + rawSeqStore->posInSequence = 0; + } +} + +/* ZSTD_opt_getNextMatchAndUpdateSeqStore(): + * Calculates the beginning and end of the next match in the current block. + * Updates 'pos' and 'posInSequence' of the ldmSeqStore. + */ +static void ZSTD_opt_getNextMatchAndUpdateSeqStore(ZSTD_optLdm_t* optLdm, U32 currPosInBlock, + U32 blockBytesRemaining) { + rawSeq currSeq; + U32 currBlockEndPos; + U32 literalsBytesRemaining; + U32 matchBytesRemaining; + + /* Setting match end position to MAX to ensure we never use an LDM during this block */ + if (optLdm->seqStore.size == 0 || optLdm->seqStore.pos >= optLdm->seqStore.size) { + optLdm->startPosInBlock = UINT_MAX; + optLdm->endPosInBlock = UINT_MAX; + return; + } + /* Calculate appropriate bytes left in matchLength and litLength after adjusting + based on ldmSeqStore->posInSequence */ + currSeq = optLdm->seqStore.seq[optLdm->seqStore.pos]; + assert(optLdm->seqStore.posInSequence <= currSeq.litLength + currSeq.matchLength); + currBlockEndPos = currPosInBlock + blockBytesRemaining; + literalsBytesRemaining = (optLdm->seqStore.posInSequence < currSeq.litLength) ? + currSeq.litLength - (U32)optLdm->seqStore.posInSequence : + 0; + matchBytesRemaining = (literalsBytesRemaining == 0) ? + currSeq.matchLength - ((U32)optLdm->seqStore.posInSequence - currSeq.litLength) : + currSeq.matchLength; + + /* If there are more literal bytes than bytes remaining in block, no ldm is possible */ + if (literalsBytesRemaining >= blockBytesRemaining) { + optLdm->startPosInBlock = UINT_MAX; + optLdm->endPosInBlock = UINT_MAX; + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, blockBytesRemaining); + return; + } + + /* Matches may be < MINMATCH by this process. In that case, we will reject them + when we are deciding whether or not to add the ldm */ + optLdm->startPosInBlock = currPosInBlock + literalsBytesRemaining; + optLdm->endPosInBlock = optLdm->startPosInBlock + matchBytesRemaining; + optLdm->offset = currSeq.offset; + + if (optLdm->endPosInBlock > currBlockEndPos) { + /* Match ends after the block ends, we can't use the whole match */ + optLdm->endPosInBlock = currBlockEndPos; + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, currBlockEndPos - currPosInBlock); + } else { + /* Consume nb of bytes equal to size of sequence left */ + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, literalsBytesRemaining + matchBytesRemaining); + } +} + +/* ZSTD_optLdm_maybeAddMatch(): + * Adds a match if it's long enough, based on it's 'matchStartPosInBlock' + * and 'matchEndPosInBlock', into 'matches'. Maintains the correct ordering of 'matches' + */ +static void ZSTD_optLdm_maybeAddMatch(ZSTD_match_t* matches, U32* nbMatches, + ZSTD_optLdm_t* optLdm, U32 currPosInBlock) { + U32 posDiff = currPosInBlock - optLdm->startPosInBlock; + /* Note: ZSTD_match_t actually contains offCode and matchLength (before subtracting MINMATCH) */ + U32 candidateMatchLength = optLdm->endPosInBlock - optLdm->startPosInBlock - posDiff; + U32 candidateOffCode = optLdm->offset + ZSTD_REP_MOVE; + + /* Ensure that current block position is not outside of the match */ + if (currPosInBlock < optLdm->startPosInBlock + || currPosInBlock >= optLdm->endPosInBlock + || candidateMatchLength < MINMATCH) { + return; + } + + if (*nbMatches == 0 || ((candidateMatchLength > matches[*nbMatches-1].len) && *nbMatches < ZSTD_OPT_NUM)) { + DEBUGLOG(6, "ZSTD_optLdm_maybeAddMatch(): Adding ldm candidate match (offCode: %u matchLength %u) at block position=%u", + candidateOffCode, candidateMatchLength, currPosInBlock); + matches[*nbMatches].len = candidateMatchLength; + matches[*nbMatches].off = candidateOffCode; + (*nbMatches)++; + } +} + +/* ZSTD_optLdm_processMatchCandidate(): + * Wrapper function to update ldm seq store and call ldm functions as necessary. + */ +static void ZSTD_optLdm_processMatchCandidate(ZSTD_optLdm_t* optLdm, ZSTD_match_t* matches, U32* nbMatches, + U32 currPosInBlock, U32 remainingBytes) { + if (optLdm->seqStore.size == 0 || optLdm->seqStore.pos >= optLdm->seqStore.size) { + return; + } + + if (currPosInBlock >= optLdm->endPosInBlock) { + if (currPosInBlock > optLdm->endPosInBlock) { + /* The position at which ZSTD_optLdm_processMatchCandidate() is called is not necessarily + * at the end of a match from the ldm seq store, and will often be some bytes + * over beyond matchEndPosInBlock. As such, we need to correct for these "overshoots" + */ + U32 posOvershoot = currPosInBlock - optLdm->endPosInBlock; + ZSTD_optLdm_skipRawSeqStoreBytes(&optLdm->seqStore, posOvershoot); + } + ZSTD_opt_getNextMatchAndUpdateSeqStore(optLdm, currPosInBlock, remainingBytes); + } + ZSTD_optLdm_maybeAddMatch(matches, nbMatches, optLdm, currPosInBlock); +} + +/*-******************************* +* Optimal parser +*********************************/ + + +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; + U32 nextToUpdate3 = ms->nextToUpdate; + + ZSTD_optimal_t* const opt = optStatePtr->priceTable; + ZSTD_match_t* const matches = optStatePtr->matchTable; + ZSTD_optimal_t lastSequence; + ZSTD_optLdm_t optLdm; + + optLdm.seqStore = ms->ldmSeqStore ? *ms->ldmSeqStore : kNullRawSeqStore; + optLdm.endPosInBlock = optLdm.startPosInBlock = optLdm.offset = 0; + ZSTD_opt_getNextMatchAndUpdateSeqStore(&optLdm, (U32)(ip-istart), (U32)(iend-ip)); + + /* init */ + DEBUGLOG(5, "ZSTD_compressBlock_opt_generic: current=%u, prefix=%u, nextToUpdate=%u", + (U32)(ip - base), ms->window.dictLimit, ms->nextToUpdate); + assert(optLevel <= 2); + 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 nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, ip, iend, dictMode, rep, ll0, minMatch); + ZSTD_optLdm_processMatchCandidate(&optLdm, matches, &nbMatches, + (U32)(ip-istart), (U32)(iend - ip)); + 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; + /* We don't need to include the actual price of the literals because + * it is static for the duration of the forward pass, and is included + * in every price. We include the literal length to avoid negative + * prices when we subtract the previous literal length. + */ + opt[0].price = ZSTD_litLengthPrice(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; + 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; + } } + 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; + } 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]); + } + } + + /* Set the repcodes of the current position. We must do it here + * because we rely on the repcodes of the 2nd to last sequence being + * correct to set the next chunks repcodes during the backward + * traversal. + */ + ZSTD_STATIC_ASSERT(sizeof(opt[cur].rep) == sizeof(repcodes_t)); + assert(cur >= opt[cur].mlen); + if (opt[cur].mlen != 0) { + U32 const prev = cur - opt[cur].mlen; + repcodes_t newReps = ZSTD_updateRep(opt[prev].rep, opt[cur].off, opt[cur].litlen==0); + ZSTD_memcpy(opt[cur].rep, &newReps, sizeof(repcodes_t)); + } else { + ZSTD_memcpy(opt[cur].rep, opt[cur - 1].rep, sizeof(repcodes_t)); + } + + /* 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 nbMatches = ZSTD_BtGetAllMatches(matches, ms, &nextToUpdate3, inr, iend, dictMode, opt[cur].rep, ll0, minMatch); + U32 matchNb; + + ZSTD_optLdm_processMatchCandidate(&optLdm, matches, &nbMatches, + (U32)(inr-istart), (U32)(iend-inr)); + + 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; + 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; + } 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); + + /* Set the next chunk's repcodes based on the repcodes of the beginning + * of the last match, and the last sequence. This avoids us having to + * update them while traversing the sequences. + */ + if (lastSequence.mlen != 0) { + repcodes_t reps = ZSTD_updateRep(opt[cur].rep, lastSequence.off, lastSequence.litlen==0); + ZSTD_memcpy(rep, &reps, sizeof(reps)); + } else { + ZSTD_memcpy(rep, opt[cur].rep, sizeof(repcodes_t)); + } + + { 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 */ + } + + assert(anchor + llen <= iend); + ZSTD_updateStats(optStatePtr, llen, anchor, offCode, mlen); + ZSTD_storeSeq(seqStore, llen, anchor, iend, offCode, mlen-MINMATCH); + anchor += advance; + ip = anchor; + } } + ZSTD_setBasePrices(optStatePtr, optLevel); + } + } /* while (ip < ilimit) */ + + /* Return the last literals size */ + return (size_t)(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 */ + ZSTD_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; + + /* 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 curr = (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 */ + && (curr == 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) */ |