| /* |
| * 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 "zstd_opt.h" |
| |
| |
| #define ZSTD_LITFREQ_ADD 2 /* scaling factor for litFreq, so that frequencies adapt faster to new stats. Also used for matchSum (?) */ |
| #define ZSTD_FREQ_DIV 4 /* log factor when using previous stats to init next stats */ |
| #define ZSTD_MAX_PRICE (1<<30) |
| |
| |
| /*-************************************* |
| * Price functions for optimal parser |
| ***************************************/ |
| static void ZSTD_setLog2Prices(optState_t* optPtr) |
| { |
| optPtr->log2litSum = ZSTD_highbit32(optPtr->litSum+1); |
| optPtr->log2litLengthSum = ZSTD_highbit32(optPtr->litLengthSum+1); |
| optPtr->log2matchLengthSum = ZSTD_highbit32(optPtr->matchLengthSum+1); |
| optPtr->log2offCodeSum = ZSTD_highbit32(optPtr->offCodeSum+1); |
| } |
| |
| |
| static void ZSTD_rescaleFreqs(optState_t* const optPtr, |
| const BYTE* const src, size_t const srcSize) |
| { |
| optPtr->staticPrices = 0; |
| |
| if (optPtr->litLengthSum == 0) { /* first init */ |
| unsigned u; |
| if (srcSize <= 1024) optPtr->staticPrices = 1; |
| |
| assert(optPtr->litFreq!=NULL); |
| for (u=0; u<=MaxLit; u++) |
| optPtr->litFreq[u] = 0; |
| for (u=0; u<srcSize; u++) |
| optPtr->litFreq[src[u]]++; |
| optPtr->litSum = 0; |
| for (u=0; u<=MaxLit; u++) { |
| optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> ZSTD_FREQ_DIV); |
| optPtr->litSum += optPtr->litFreq[u]; |
| } |
| |
| for (u=0; u<=MaxLL; u++) |
| optPtr->litLengthFreq[u] = 1; |
| optPtr->litLengthSum = MaxLL+1; |
| for (u=0; u<=MaxML; u++) |
| optPtr->matchLengthFreq[u] = 1; |
| optPtr->matchLengthSum = MaxML+1; |
| for (u=0; u<=MaxOff; u++) |
| optPtr->offCodeFreq[u] = 1; |
| optPtr->offCodeSum = (MaxOff+1); |
| |
| } else { |
| unsigned u; |
| |
| optPtr->litSum = 0; |
| for (u=0; u<=MaxLit; u++) { |
| optPtr->litFreq[u] = 1 + (optPtr->litFreq[u] >> (ZSTD_FREQ_DIV+1)); |
| optPtr->litSum += optPtr->litFreq[u]; |
| } |
| optPtr->litLengthSum = 0; |
| for (u=0; u<=MaxLL; u++) { |
| optPtr->litLengthFreq[u] = 1 + (optPtr->litLengthFreq[u]>>(ZSTD_FREQ_DIV+1)); |
| optPtr->litLengthSum += optPtr->litLengthFreq[u]; |
| } |
| optPtr->matchLengthSum = 0; |
| for (u=0; u<=MaxML; u++) { |
| optPtr->matchLengthFreq[u] = 1 + (optPtr->matchLengthFreq[u]>>ZSTD_FREQ_DIV); |
| optPtr->matchLengthSum += optPtr->matchLengthFreq[u]; |
| } |
| optPtr->offCodeSum = 0; |
| for (u=0; u<=MaxOff; u++) { |
| optPtr->offCodeFreq[u] = 1 + (optPtr->offCodeFreq[u]>>ZSTD_FREQ_DIV); |
| optPtr->offCodeSum += optPtr->offCodeFreq[u]; |
| } |
| } |
| |
| ZSTD_setLog2Prices(optPtr); |
| } |
| |
| |
| /* ZSTD_rawLiteralsCost() : |
| * cost of literals (only) in given segment (which length can be null) |
| * does not include cost of literalLength symbol */ |
| static U32 ZSTD_rawLiteralsCost(const BYTE* const literals, U32 const litLength, |
| const optState_t* const optPtr) |
| { |
| if (optPtr->staticPrices) return (litLength*6); /* 6 bit per literal - no statistic used */ |
| if (litLength == 0) return 0; |
| |
| /* literals */ |
| { U32 u; |
| U32 cost = litLength * optPtr->log2litSum; |
| for (u=0; u < litLength; u++) |
| cost -= ZSTD_highbit32(optPtr->litFreq[literals[u]]+1); |
| return cost; |
| } |
| } |
| |
| /* ZSTD_litLengthPrice() : |
| * cost of literalLength symbol */ |
| static U32 ZSTD_litLengthPrice(U32 const litLength, const optState_t* const optPtr) |
| { |
| if (optPtr->staticPrices) return ZSTD_highbit32((U32)litLength+1); |
| |
| /* literal Length */ |
| { U32 const llCode = ZSTD_LLcode(litLength); |
| U32 const price = LL_bits[llCode] + optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1); |
| return price; |
| } |
| } |
| |
| /* ZSTD_litLengthPrice() : |
| * cost of the literal part of a sequence, |
| * including literals themselves, and literalLength symbol */ |
| static U32 ZSTD_fullLiteralsCost(const BYTE* const literals, U32 const litLength, |
| const optState_t* const optPtr) |
| { |
| return ZSTD_rawLiteralsCost(literals, litLength, optPtr) |
| + ZSTD_litLengthPrice(litLength, optPtr); |
| } |
| |
| /* 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) |
| { |
| if (optPtr->staticPrices) return ZSTD_highbit32(litLength+1); |
| |
| /* literal Length */ |
| { U32 const llCode = ZSTD_LLcode(litLength); |
| int const contribution = LL_bits[llCode] |
| + ZSTD_highbit32(optPtr->litLengthFreq[0]+1) |
| - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1); |
| #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 const contribution = ZSTD_rawLiteralsCost(literals, litLength, optPtr) |
| + ZSTD_litLengthContribution(litLength, optPtr); |
| 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->staticPrices) /* fixed scheme, do not use statistics */ |
| return ZSTD_highbit32((U32)mlBase+1) + 16 + offCode; |
| |
| price = offCode + optPtr->log2offCodeSum - ZSTD_highbit32(optPtr->offCodeFreq[offCode]+1); |
| if ((optLevel<2) /*static*/ && offCode >= 20) price += (offCode-19)*2; /* handicap for long distance offsets, favor decompression speed */ |
| |
| /* match Length */ |
| { U32 const mlCode = ZSTD_MLcode(mlBase); |
| price += ML_bits[mlCode] + optPtr->log2matchLengthSum - ZSTD_highbit32(optPtr->matchLengthFreq[mlCode]+1); |
| } |
| |
| DEBUGLOG(8, "ZSTD_getMatchPrice(ml:%u) = %u", matchLength, price); |
| return price; |
| } |
| |
| static void ZSTD_updateStats(optState_t* const optPtr, |
| U32 litLength, const BYTE* literals, |
| U32 offsetCode, U32 matchLength) |
| { |
| /* literals */ |
| { 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, ZSTD_compressionParameters const* cParams, |
| const BYTE* const ip, const BYTE* const iend, |
| U32 const mls, U32 const extDict) |
| { |
| 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 */ |
| |
| 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 extDict is incorrectly set to 0 */ |
| 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, ZSTD_compressionParameters const* cParams, |
| const BYTE* const ip, const BYTE* const iend, |
| const U32 mls, const U32 extDict) |
| { |
| const BYTE* const base = ms->window.base; |
| U32 const target = (U32)(ip - base); |
| U32 idx = ms->nextToUpdate; |
| DEBUGLOG(7, "ZSTD_updateTree_internal, from %u to %u (extDict:%u)", |
| idx, target, extDict); |
| |
| while(idx < target) |
| idx += ZSTD_insertBt1(ms, cParams, base+idx, iend, mls, extDict); |
| ms->nextToUpdate = target; |
| } |
| |
| void ZSTD_updateTree( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* iend) |
| { |
| ZSTD_updateTree_internal(ms, cParams, ip, iend, cParams->searchLength, 0 /*extDict*/); |
| } |
| |
| FORCE_INLINE_TEMPLATE |
| U32 ZSTD_insertBtAndGetAllMatches ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* const ip, const BYTE* const iLimit, int const extDict, |
| U32 rep[ZSTD_REP_NUM], U32 const ll0, |
| ZSTD_match_t* matches, const U32 lengthToBeat, U32 const mls /* template */) |
| { |
| 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* 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; |
| |
| size_t bestLength = lengthToBeat-1; |
| DEBUGLOG(7, "ZSTD_insertBtAndGetAllMatches"); |
| |
| /* check repCode */ |
| { 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 = dictBase + repIndex; |
| assert(current >= windowLow); |
| if ( extDict /* this case only valid in extDict mode */ |
| && ( ((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; |
| } } |
| /* save longer solution */ |
| if (repLen > bestLength) { |
| DEBUGLOG(8, "found rep-match %u of length %u", |
| repCode - ll0, (U32)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 > windowLow) |
| & (current - matchIndex3 < (1<<18)) /*heuristic : longer distance likely too expensive*/ ) { |
| size_t mlen; |
| if ((!extDict) /*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; |
| } } } } |
| |
| hashTable[h] = current; /* Update Hash Table */ |
| |
| while (nbCompares-- && (matchIndex > windowLow)) { |
| 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 ((!extDict) || (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", |
| (U32)matchLength, current - matchIndex); |
| 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) break; |
| if (ip+matchLength == iLimit) { /* equal : no way to know if inf or sup */ |
| 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(matchEndIdx > current+8); |
| ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */ |
| return mnum; |
| } |
| |
| |
| FORCE_INLINE_TEMPLATE U32 ZSTD_BtGetAllMatches ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* const iHighLimit, int const extDict, |
| U32 rep[ZSTD_REP_NUM], U32 const ll0, |
| ZSTD_match_t* matches, U32 const lengthToBeat) |
| { |
| U32 const matchLengthSearch = cParams->searchLength; |
| DEBUGLOG(7, "ZSTD_BtGetAllMatches"); |
| if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */ |
| ZSTD_updateTree_internal(ms, cParams, ip, iHighLimit, matchLengthSearch, extDict); |
| switch(matchLengthSearch) |
| { |
| case 3 : return ZSTD_insertBtAndGetAllMatches(ms, cParams, ip, iHighLimit, extDict, rep, ll0, matches, lengthToBeat, 3); |
| default : |
| case 4 : return ZSTD_insertBtAndGetAllMatches(ms, cParams, ip, iHighLimit, extDict, rep, ll0, matches, lengthToBeat, 4); |
| case 5 : return ZSTD_insertBtAndGetAllMatches(ms, cParams, ip, iHighLimit, extDict, rep, ll0, matches, lengthToBeat, 5); |
| case 7 : |
| case 6 : return ZSTD_insertBtAndGetAllMatches(ms, cParams, ip, iHighLimit, extDict, rep, ll0, matches, lengthToBeat, 6); |
| } |
| } |
| |
| |
| /*-******************************* |
| * Optimal parser |
| *********************************/ |
| typedef struct repcodes_s { |
| U32 rep[3]; |
| } repcodes_t; |
| |
| repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0) |
| { |
| repcodes_t newReps; |
| if (offset >= ZSTD_REP_NUM) { /* full offset */ |
| newReps.rep[2] = rep[1]; |
| newReps.rep[1] = rep[0]; |
| newReps.rep[0] = offset - ZSTD_REP_MOVE; |
| } else { /* repcode */ |
| U32 const repCode = offset + ll0; |
| if (repCode > 0) { /* note : if repCode==0, no change */ |
| U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode]; |
| newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2]; |
| newReps.rep[1] = rep[0]; |
| newReps.rep[0] = currentOffset; |
| } else { /* repCode == 0 */ |
| memcpy(&newReps, rep, sizeof(newReps)); |
| } |
| } |
| return newReps; |
| } |
| |
| |
| typedef struct { |
| const BYTE* anchor; |
| U32 litlen; |
| U32 rawLitCost; |
| } cachedLiteralPrice_t; |
| |
| static U32 ZSTD_rawLiteralsCost_cached( |
| cachedLiteralPrice_t* const cachedLitPrice, |
| const BYTE* const anchor, U32 const litlen, |
| const optState_t* const optStatePtr) |
| { |
| U32 startCost; |
| U32 remainingLength; |
| const BYTE* startPosition; |
| |
| if (anchor == cachedLitPrice->anchor) { |
| startCost = cachedLitPrice->rawLitCost; |
| startPosition = anchor + cachedLitPrice->litlen; |
| assert(litlen >= cachedLitPrice->litlen); |
| remainingLength = litlen - cachedLitPrice->litlen; |
| } else { |
| startCost = 0; |
| startPosition = anchor; |
| remainingLength = litlen; |
| } |
| |
| { U32 const rawLitCost = startCost + ZSTD_rawLiteralsCost(startPosition, remainingLength, optStatePtr); |
| cachedLitPrice->anchor = anchor; |
| cachedLitPrice->litlen = litlen; |
| cachedLitPrice->rawLitCost = rawLitCost; |
| return rawLitCost; |
| } |
| } |
| |
| static U32 ZSTD_fullLiteralsCost_cached( |
| cachedLiteralPrice_t* const cachedLitPrice, |
| const BYTE* const anchor, U32 const litlen, |
| const optState_t* const optStatePtr) |
| { |
| return ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr) |
| + ZSTD_litLengthPrice(litlen, optStatePtr); |
| } |
| |
| static int ZSTD_literalsContribution_cached( |
| cachedLiteralPrice_t* const cachedLitPrice, |
| const BYTE* const anchor, U32 const litlen, |
| const optState_t* const optStatePtr) |
| { |
| int const contribution = ZSTD_rawLiteralsCost_cached(cachedLitPrice, anchor, litlen, optStatePtr) |
| + ZSTD_litLengthContribution(litlen, optStatePtr); |
| return contribution; |
| } |
| |
| FORCE_INLINE_TEMPLATE |
| size_t ZSTD_compressBlock_opt_generic(ZSTD_matchState_t* ms,seqStore_t* seqStore, |
| U32 rep[ZSTD_REP_NUM], |
| ZSTD_compressionParameters const* cParams, |
| const void* src, size_t srcSize, |
| const int optLevel, const int extDict) |
| { |
| 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; |
| |
| U32 const sufficient_len = MIN(cParams->targetLength, ZSTD_OPT_NUM -1); |
| U32 const minMatch = (cParams->searchLength == 3) ? 3 : 4; |
| |
| ZSTD_optimal_t* const opt = optStatePtr->priceTable; |
| ZSTD_match_t* const matches = optStatePtr->matchTable; |
| cachedLiteralPrice_t cachedLitPrice; |
| |
| /* init */ |
| DEBUGLOG(5, "ZSTD_compressBlock_opt_generic"); |
| ms->nextToUpdate3 = ms->nextToUpdate; |
| ZSTD_rescaleFreqs(optStatePtr, (const BYTE*)src, srcSize); |
| ip += (ip==prefixStart); |
| memset(&cachedLitPrice, 0, sizeof(cachedLitPrice)); |
| |
| /* Match Loop */ |
| while (ip < ilimit) { |
| U32 cur, last_pos = 0; |
| U32 best_mlen, best_off; |
| |
| /* find first match */ |
| { U32 const litlen = (U32)(ip - anchor); |
| U32 const ll0 = !litlen; |
| U32 const nbMatches = ZSTD_BtGetAllMatches(ms, cParams, ip, iend, extDict, rep, ll0, matches, minMatch); |
| if (!nbMatches) { ip++; continue; } |
| |
| /* initialize opt[0] */ |
| { U32 i ; for (i=0; i<ZSTD_REP_NUM; i++) opt[0].rep[i] = rep[i]; } |
| opt[0].mlen = 1; |
| opt[0].litlen = litlen; |
| |
| /* large match -> immediate encoding */ |
| { U32 const maxML = matches[nbMatches-1].len; |
| DEBUGLOG(7, "found %u matches of maxLength=%u and offset=%u at cPos=%u => start new serie", |
| nbMatches, maxML, matches[nbMatches-1].off, (U32)(ip-prefixStart)); |
| |
| if (maxML > sufficient_len) { |
| best_mlen = maxML; |
| best_off = matches[nbMatches-1].off; |
| DEBUGLOG(7, "large match (%u>%u), immediate encoding", |
| best_mlen, sufficient_len); |
| cur = 0; |
| last_pos = 1; |
| goto _shortestPath; |
| } } |
| |
| /* set prices for first matches starting position == 0 */ |
| { U32 const literalsPrice = ZSTD_fullLiteralsCost_cached(&cachedLitPrice, anchor, litlen, optStatePtr); |
| U32 pos; |
| U32 matchNb; |
| for (pos = 0; pos < minMatch; pos++) { |
| opt[pos].mlen = 1; |
| opt[pos].price = ZSTD_MAX_PRICE; |
| } |
| 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 = literalsPrice + ZSTD_getMatchPrice(offset, pos, optStatePtr, optLevel); |
| DEBUGLOG(7, "rPos:%u => set initial price : %u", |
| pos, matchPrice); |
| opt[pos].mlen = pos; |
| opt[pos].off = offset; |
| opt[pos].litlen = litlen; |
| opt[pos].price = matchPrice; |
| 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); |
| |
| /* Fix current position with one literal if cheaper */ |
| { U32 const litlen = (opt[cur-1].mlen == 1) ? opt[cur-1].litlen + 1 : 1; |
| int price; /* note : contribution can be negative */ |
| if (cur > litlen) { |
| price = opt[cur - litlen].price + ZSTD_literalsContribution(inr-litlen, litlen, optStatePtr); |
| } else { |
| price = ZSTD_literalsContribution_cached(&cachedLitPrice, anchor, litlen, optStatePtr); |
| } |
| assert(price < 1000000000); /* overflow check */ |
| if (price <= opt[cur].price) { |
| DEBUGLOG(7, "rPos:%u : better price (%u<%u) using literal", |
| cur, price, opt[cur].price); |
| opt[cur].mlen = 1; |
| opt[cur].off = 0; |
| opt[cur].litlen = litlen; |
| opt[cur].price = price; |
| memcpy(opt[cur].rep, opt[cur-1].rep, sizeof(opt[cur].rep)); |
| } } |
| |
| /* last match must start at a minimum distance of 8 from oend */ |
| if (inr > ilimit) continue; |
| |
| if (cur == last_pos) break; |
| |
| if ( (optLevel==0) /*static*/ |
| && (opt[cur+1].price <= opt[cur].price) ) |
| continue; /* skip unpromising positions; about ~+6% speed, -0.01 ratio */ |
| |
| { U32 const ll0 = (opt[cur].mlen != 1); |
| U32 const litlen = (opt[cur].mlen == 1) ? opt[cur].litlen : 0; |
| U32 const previousPrice = (cur > litlen) ? opt[cur-litlen].price : 0; |
| U32 const basePrice = previousPrice + ZSTD_fullLiteralsCost(inr-litlen, litlen, optStatePtr); |
| U32 const nbMatches = ZSTD_BtGetAllMatches(ms, cParams, inr, iend, extDict, opt[cur].rep, ll0, matches, minMatch); |
| U32 matchNb; |
| if (!nbMatches) continue; |
| |
| { U32 const maxML = matches[nbMatches-1].len; |
| DEBUGLOG(7, "rPos:%u, found %u matches, of maxLength=%u", |
| cur, nbMatches, maxML); |
| |
| if ( (maxML > sufficient_len) |
| | (cur + maxML >= ZSTD_OPT_NUM) ) { |
| best_mlen = maxML; |
| best_off = matches[nbMatches-1].off; |
| last_pos = cur + 1; |
| goto _shortestPath; |
| } |
| } |
| |
| /* set prices using matches found at position == cur */ |
| for (matchNb = 0; matchNb < nbMatches; matchNb++) { |
| U32 const offset = matches[matchNb].off; |
| repcodes_t const repHistory = ZSTD_updateRep(opt[cur].rep, offset, ll0); |
| U32 const lastML = matches[matchNb].len; |
| U32 const startML = (matchNb>0) ? matches[matchNb-1].len+1 : minMatch; |
| U32 mlen; |
| |
| DEBUGLOG(7, "testing match %u => offCode=%u, mlen=%u, llen=%u", |
| matchNb, matches[matchNb].off, lastML, litlen); |
| |
| for (mlen = lastML; mlen >= startML; mlen--) { |
| U32 const pos = cur + mlen; |
| int const price = basePrice + ZSTD_getMatchPrice(offset, mlen, optStatePtr, optLevel); |
| |
| if ((pos > last_pos) || (price < opt[pos].price)) { |
| DEBUGLOG(7, "rPos:%u => new better price (%u<%u)", |
| pos, price, opt[pos].price); |
| while (last_pos < pos) { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; } |
| opt[pos].mlen = mlen; |
| opt[pos].off = offset; |
| opt[pos].litlen = litlen; |
| opt[pos].price = price; |
| memcpy(opt[pos].rep, &repHistory, sizeof(repHistory)); |
| } else { |
| if (optLevel==0) break; /* gets ~+10% speed for about -0.01 ratio loss */ |
| } |
| } } } |
| } /* for (cur = 1; cur <= last_pos; cur++) */ |
| |
| best_mlen = opt[last_pos].mlen; |
| best_off = opt[last_pos].off; |
| cur = last_pos - best_mlen; |
| |
| _shortestPath: /* cur, last_pos, best_mlen, best_off have to be set */ |
| assert(opt[0].mlen == 1); |
| |
| /* reverse traversal */ |
| DEBUGLOG(7, "start reverse traversal (last_pos:%u, cur:%u)", |
| last_pos, cur); |
| { U32 selectedMatchLength = best_mlen; |
| U32 selectedOffset = best_off; |
| U32 pos = cur; |
| while (1) { |
| U32 const mlen = opt[pos].mlen; |
| U32 const off = opt[pos].off; |
| opt[pos].mlen = selectedMatchLength; |
| opt[pos].off = selectedOffset; |
| selectedMatchLength = mlen; |
| selectedOffset = off; |
| if (mlen > pos) break; |
| pos -= mlen; |
| } } |
| |
| /* save sequences */ |
| { U32 pos; |
| for (pos=0; pos < last_pos; ) { |
| U32 const llen = (U32)(ip - anchor); |
| U32 const mlen = opt[pos].mlen; |
| U32 const offset = opt[pos].off; |
| if (mlen == 1) { ip++; pos++; continue; } /* literal position => move on */ |
| pos += mlen; ip += mlen; |
| |
| /* repcodes update : like ZSTD_updateRep(), but update in place */ |
| if (offset >= ZSTD_REP_NUM) { /* full offset */ |
| rep[2] = rep[1]; |
| rep[1] = rep[0]; |
| rep[0] = offset - ZSTD_REP_MOVE; |
| } else { /* repcode */ |
| U32 const repCode = offset + (llen==0); |
| if (repCode) { /* note : if repCode==0, no change */ |
| U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode]; |
| if (repCode >= 2) rep[2] = rep[1]; |
| rep[1] = rep[0]; |
| rep[0] = currentOffset; |
| } |
| } |
| |
| ZSTD_updateStats(optStatePtr, llen, anchor, offset, mlen); |
| ZSTD_storeSeq(seqStore, llen, anchor, offset, mlen-MINMATCH); |
| anchor = ip; |
| } } |
| ZSTD_setLog2Prices(optStatePtr); |
| } /* 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], |
| ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize) |
| { |
| DEBUGLOG(5, "ZSTD_compressBlock_btopt"); |
| return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, cParams, src, srcSize, 0 /*optLevel*/, 0 /*extDict*/); |
| } |
| |
| size_t ZSTD_compressBlock_btultra( |
| ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
| ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize) |
| { |
| return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, cParams, src, srcSize, 2 /*optLevel*/, 0 /*extDict*/); |
| } |
| |
| size_t ZSTD_compressBlock_btopt_extDict( |
| ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
| ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize) |
| { |
| return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, cParams, src, srcSize, 0 /*optLevel*/, 1 /*extDict*/); |
| } |
| |
| size_t ZSTD_compressBlock_btultra_extDict( |
| ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], |
| ZSTD_compressionParameters const* cParams, void const* src, size_t srcSize) |
| { |
| return ZSTD_compressBlock_opt_generic(ms, seqStore, rep, cParams, src, srcSize, 2 /*optLevel*/, 1 /*extDict*/); |
| } |