| /* |
| * Copyright (c) 2016-present, 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_lazy.h" |
| |
| |
| /*-************************************* |
| * Binary Tree search |
| ***************************************/ |
| |
| void ZSTD_updateDUBT( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* iend, |
| U32 mls) |
| { |
| U32* const hashTable = ms->hashTable; |
| U32 const hashLog = cParams->hashLog; |
| |
| U32* const bt = ms->chainTable; |
| U32 const btLog = cParams->chainLog - 1; |
| U32 const btMask = (1 << btLog) - 1; |
| |
| const BYTE* const base = ms->window.base; |
| U32 const target = (U32)(ip - base); |
| U32 idx = ms->nextToUpdate; |
| |
| if (idx != target) |
| DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)", |
| idx, target, ms->window.dictLimit); |
| assert(ip + 8 <= iend); /* condition for ZSTD_hashPtr */ |
| (void)iend; |
| |
| assert(idx >= ms->window.dictLimit); /* condition for valid base+idx */ |
| for ( ; idx < target ; idx++) { |
| size_t const h = ZSTD_hashPtr(base + idx, hashLog, mls); /* assumption : ip + 8 <= iend */ |
| U32 const matchIndex = hashTable[h]; |
| |
| U32* const nextCandidatePtr = bt + 2*(idx&btMask); |
| U32* const sortMarkPtr = nextCandidatePtr + 1; |
| |
| DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx); |
| hashTable[h] = idx; /* Update Hash Table */ |
| *nextCandidatePtr = matchIndex; /* update BT like a chain */ |
| *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK; |
| } |
| ms->nextToUpdate = target; |
| } |
| |
| |
| /** ZSTD_insertDUBT1() : |
| * sort one already inserted but unsorted position |
| * assumption : current >= btlow == (current - btmask) |
| * doesn't fail */ |
| static void ZSTD_insertDUBT1( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| U32 current, const BYTE* inputEnd, |
| U32 nbCompares, U32 btLow, int extDict) |
| { |
| U32* const bt = ms->chainTable; |
| U32 const btLog = cParams->chainLog - 1; |
| U32 const btMask = (1 << btLog) - 1; |
| 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 ip = (current>=dictLimit) ? base + current : dictBase + current; |
| const BYTE* const iend = (current>=dictLimit) ? inputEnd : dictBase + dictLimit; |
| const BYTE* const dictEnd = dictBase + dictLimit; |
| const BYTE* const prefixStart = base + dictLimit; |
| const BYTE* match; |
| U32* smallerPtr = bt + 2*(current&btMask); |
| U32* largerPtr = smallerPtr + 1; |
| U32 matchIndex = *smallerPtr; |
| U32 dummy32; /* to be nullified at the end */ |
| U32 const windowLow = ms->window.lowLimit; |
| |
| DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)", |
| current, dictLimit, windowLow); |
| assert(current >= btLow); |
| assert(ip < iend); /* condition for ZSTD_count */ |
| |
| 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); |
| |
| if ( (!extDict) |
| || (matchIndex+matchLength >= dictLimit) /* both in current segment*/ |
| || (current < dictLimit) /* both in extDict */) { |
| const BYTE* const mBase = !extDict || ((matchIndex+matchLength) >= dictLimit) ? base : dictBase; |
| assert( (matchIndex+matchLength >= dictLimit) /* might be wrong if extDict is incorrectly set to 0 */ |
| || (current < dictLimit) ); |
| match = mBase + 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] */ |
| } |
| |
| DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ", |
| current, 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 */ |
| DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u", |
| matchIndex, btLow, nextPtr[1]); |
| 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 */ |
| DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u", |
| matchIndex, btLow, nextPtr[0]); |
| largerPtr = nextPtr; |
| matchIndex = nextPtr[0]; |
| } } |
| |
| *smallerPtr = *largerPtr = 0; |
| } |
| |
| |
| static size_t ZSTD_DUBT_findBestMatch ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* const ip, const BYTE* const iend, |
| size_t* offsetPtr, |
| 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 matchIndex = hashTable[h]; |
| |
| const BYTE* const base = ms->window.base; |
| U32 const current = (U32)(ip-base); |
| U32 const windowLow = ms->window.lowLimit; |
| |
| U32* const bt = ms->chainTable; |
| U32 const btLog = cParams->chainLog - 1; |
| U32 const btMask = (1 << btLog) - 1; |
| U32 const btLow = (btMask >= current) ? 0 : current - btMask; |
| U32 const unsortLimit = MAX(btLow, windowLow); |
| |
| U32* nextCandidate = bt + 2*(matchIndex&btMask); |
| U32* unsortedMark = bt + 2*(matchIndex&btMask) + 1; |
| U32 nbCompares = 1U << cParams->searchLog; |
| U32 nbCandidates = nbCompares; |
| U32 previousCandidate = 0; |
| |
| DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", current); |
| assert(ip <= iend-8); /* required for h calculation */ |
| |
| /* reach end of unsorted candidates list */ |
| while ( (matchIndex > unsortLimit) |
| && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK) |
| && (nbCandidates > 1) ) { |
| DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted", |
| matchIndex); |
| *unsortedMark = previousCandidate; |
| previousCandidate = matchIndex; |
| matchIndex = *nextCandidate; |
| nextCandidate = bt + 2*(matchIndex&btMask); |
| unsortedMark = bt + 2*(matchIndex&btMask) + 1; |
| nbCandidates --; |
| } |
| |
| if ( (matchIndex > unsortLimit) |
| && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) { |
| DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u", |
| matchIndex); |
| *nextCandidate = *unsortedMark = 0; /* nullify next candidate if it's still unsorted (note : simplification, detrimental to compression ratio, beneficial for speed) */ |
| } |
| |
| /* batch sort stacked candidates */ |
| matchIndex = previousCandidate; |
| while (matchIndex) { /* will end on matchIndex == 0 */ |
| U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1; |
| U32 const nextCandidateIdx = *nextCandidateIdxPtr; |
| ZSTD_insertDUBT1(ms, cParams, matchIndex, iend, |
| nbCandidates, unsortLimit, extDict); |
| matchIndex = nextCandidateIdx; |
| nbCandidates++; |
| } |
| |
| /* find longest match */ |
| { size_t commonLengthSmaller=0, commonLengthLarger=0; |
| 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; |
| U32* smallerPtr = bt + 2*(current&btMask); |
| U32* largerPtr = bt + 2*(current&btMask) + 1; |
| U32 matchEndIdx = current+8+1; |
| U32 dummy32; /* to be nullified at the end */ |
| size_t bestLength = 0; |
| |
| matchIndex = hashTable[h]; |
| 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; |
| |
| if ((!extDict) || (matchIndex+matchLength >= dictLimit)) { |
| 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) { |
| if (matchLength > matchEndIdx - matchIndex) |
| matchEndIdx = matchIndex + (U32)matchLength; |
| if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) |
| bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex; |
| if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */ |
| break; /* drop, to guarantee consistency (miss a little bit of compression) */ |
| } |
| } |
| |
| if (match[matchLength] < ip[matchLength]) { |
| /* 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 the search */ |
| smallerPtr = nextPtr+1; /* new "smaller" => larger of match */ |
| matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */ |
| } else { |
| /* match is larger than current */ |
| *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); /* ensure nextToUpdate is increased */ |
| ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */ |
| if (bestLength >= MINMATCH) { |
| U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex; |
| DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)", |
| current, (U32)bestLength, (U32)*offsetPtr, mIndex); |
| } |
| return bestLength; |
| } |
| } |
| |
| |
| /** ZSTD_BtFindBestMatch() : Tree updater, providing best match */ |
| static size_t ZSTD_BtFindBestMatch ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* const ip, const BYTE* const iLimit, |
| size_t* offsetPtr, |
| const U32 mls /* template */) |
| { |
| DEBUGLOG(7, "ZSTD_BtFindBestMatch"); |
| if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */ |
| ZSTD_updateDUBT(ms, cParams, ip, iLimit, mls); |
| return ZSTD_DUBT_findBestMatch(ms, cParams, ip, iLimit, offsetPtr, mls, 0); |
| } |
| |
| |
| static size_t ZSTD_BtFindBestMatch_selectMLS ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* const iLimit, |
| size_t* offsetPtr) |
| { |
| switch(cParams->searchLength) |
| { |
| default : /* includes case 3 */ |
| case 4 : return ZSTD_BtFindBestMatch(ms, cParams, ip, iLimit, offsetPtr, 4); |
| case 5 : return ZSTD_BtFindBestMatch(ms, cParams, ip, iLimit, offsetPtr, 5); |
| case 7 : |
| case 6 : return ZSTD_BtFindBestMatch(ms, cParams, ip, iLimit, offsetPtr, 6); |
| } |
| } |
| |
| |
| /** Tree updater, providing best match */ |
| static size_t ZSTD_BtFindBestMatch_extDict ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* const ip, const BYTE* const iLimit, |
| size_t* offsetPtr, |
| const U32 mls) |
| { |
| DEBUGLOG(7, "ZSTD_BtFindBestMatch_extDict"); |
| if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */ |
| ZSTD_updateDUBT(ms, cParams, ip, iLimit, mls); |
| return ZSTD_DUBT_findBestMatch(ms, cParams, ip, iLimit, offsetPtr, mls, 1); |
| } |
| |
| |
| static size_t ZSTD_BtFindBestMatch_selectMLS_extDict ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* const iLimit, |
| size_t* offsetPtr) |
| { |
| switch(cParams->searchLength) |
| { |
| default : /* includes case 3 */ |
| case 4 : return ZSTD_BtFindBestMatch_extDict(ms, cParams, ip, iLimit, offsetPtr, 4); |
| case 5 : return ZSTD_BtFindBestMatch_extDict(ms, cParams, ip, iLimit, offsetPtr, 5); |
| case 7 : |
| case 6 : return ZSTD_BtFindBestMatch_extDict(ms, cParams, ip, iLimit, offsetPtr, 6); |
| } |
| } |
| |
| |
| |
| /* ********************************* |
| * Hash Chain |
| ***********************************/ |
| #define NEXT_IN_CHAIN(d, mask) chainTable[(d) & mask] |
| |
| /* Update chains up to ip (excluded) |
| Assumption : always within prefix (i.e. not within extDict) */ |
| static U32 ZSTD_insertAndFindFirstIndex_internal( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, U32 const mls) |
| { |
| U32* const hashTable = ms->hashTable; |
| const U32 hashLog = cParams->hashLog; |
| U32* const chainTable = ms->chainTable; |
| const U32 chainMask = (1 << cParams->chainLog) - 1; |
| const BYTE* const base = ms->window.base; |
| const U32 target = (U32)(ip - base); |
| U32 idx = ms->nextToUpdate; |
| |
| while(idx < target) { /* catch up */ |
| size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls); |
| NEXT_IN_CHAIN(idx, chainMask) = hashTable[h]; |
| hashTable[h] = idx; |
| idx++; |
| } |
| |
| ms->nextToUpdate = target; |
| return hashTable[ZSTD_hashPtr(ip, hashLog, mls)]; |
| } |
| |
| U32 ZSTD_insertAndFindFirstIndex( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip) |
| { |
| return ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, cParams->searchLength); |
| } |
| |
| |
| /* inlining is important to hardwire a hot branch (template emulation) */ |
| FORCE_INLINE_TEMPLATE |
| size_t ZSTD_HcFindBestMatch_generic ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* const ip, const BYTE* const iLimit, |
| size_t* offsetPtr, |
| const U32 mls, const U32 extDict) |
| { |
| U32* const chainTable = ms->chainTable; |
| const U32 chainSize = (1 << cParams->chainLog); |
| const U32 chainMask = chainSize-1; |
| const BYTE* const base = ms->window.base; |
| const BYTE* const dictBase = ms->window.dictBase; |
| const U32 dictLimit = ms->window.dictLimit; |
| const BYTE* const prefixStart = base + dictLimit; |
| const BYTE* const dictEnd = dictBase + dictLimit; |
| const U32 lowLimit = ms->window.lowLimit; |
| const U32 current = (U32)(ip-base); |
| const U32 minChain = current > chainSize ? current - chainSize : 0; |
| U32 nbAttempts = 1U << cParams->searchLog; |
| size_t ml=4-1; |
| |
| /* HC4 match finder */ |
| U32 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls); |
| |
| for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) { |
| size_t currentMl=0; |
| if ((!extDict) || matchIndex >= dictLimit) { |
| const BYTE* const match = base + matchIndex; |
| if (match[ml] == ip[ml]) /* potentially better */ |
| currentMl = ZSTD_count(ip, match, iLimit); |
| } else { |
| const BYTE* const match = dictBase + matchIndex; |
| assert(match+4 <= dictEnd); |
| if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */ |
| currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4; |
| } |
| |
| /* save best solution */ |
| if (currentMl > ml) { |
| ml = currentMl; |
| *offsetPtr = current - matchIndex + ZSTD_REP_MOVE; |
| if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */ |
| } |
| |
| if (matchIndex <= minChain) break; |
| matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask); |
| } |
| |
| return ml; |
| } |
| |
| |
| FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* const iLimit, |
| size_t* offsetPtr) |
| { |
| switch(cParams->searchLength) |
| { |
| default : /* includes case 3 */ |
| case 4 : return ZSTD_HcFindBestMatch_generic(ms, cParams, ip, iLimit, offsetPtr, 4, 0); |
| case 5 : return ZSTD_HcFindBestMatch_generic(ms, cParams, ip, iLimit, offsetPtr, 5, 0); |
| case 7 : |
| case 6 : return ZSTD_HcFindBestMatch_generic(ms, cParams, ip, iLimit, offsetPtr, 6, 0); |
| } |
| } |
| |
| |
| FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS ( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* const iLimit, |
| size_t* const offsetPtr) |
| { |
| switch(cParams->searchLength) |
| { |
| default : /* includes case 3 */ |
| case 4 : return ZSTD_HcFindBestMatch_generic(ms, cParams, ip, iLimit, offsetPtr, 4, 1); |
| case 5 : return ZSTD_HcFindBestMatch_generic(ms, cParams, ip, iLimit, offsetPtr, 5, 1); |
| case 7 : |
| case 6 : return ZSTD_HcFindBestMatch_generic(ms, cParams, ip, iLimit, offsetPtr, 6, 1); |
| } |
| } |
| |
| |
| /* ******************************* |
| * Common parser - lazy strategy |
| *********************************/ |
| FORCE_INLINE_TEMPLATE |
| size_t ZSTD_compressBlock_lazy_generic( |
| ZSTD_matchState_t* ms, seqStore_t* seqStore, |
| U32 rep[ZSTD_REP_NUM], |
| ZSTD_compressionParameters const* cParams, |
| const void* src, size_t srcSize, |
| const U32 searchMethod, const U32 depth) |
| { |
| 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 + ms->window.dictLimit; |
| |
| typedef size_t (*searchMax_f)( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr); |
| searchMax_f const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS; |
| U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0; |
| |
| /* init */ |
| ip += (ip==base); |
| ms->nextToUpdate3 = ms->nextToUpdate; |
| { U32 const maxRep = (U32)(ip-base); |
| if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0; |
| if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0; |
| } |
| |
| /* Match Loop */ |
| while (ip < ilimit) { |
| size_t matchLength=0; |
| size_t offset=0; |
| const BYTE* start=ip+1; |
| |
| /* check repCode */ |
| if ((offset_1>0) & (MEM_read32(ip+1) == MEM_read32(ip+1 - offset_1))) { |
| /* repcode : we take it */ |
| matchLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4; |
| if (depth==0) goto _storeSequence; |
| } |
| |
| /* first search (depth 0) */ |
| { size_t offsetFound = 99999999; |
| size_t const ml2 = searchMax(ms, cParams, ip, iend, &offsetFound); |
| if (ml2 > matchLength) |
| matchLength = ml2, start = ip, offset=offsetFound; |
| } |
| |
| if (matchLength < 4) { |
| ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */ |
| continue; |
| } |
| |
| /* let's try to find a better solution */ |
| if (depth>=1) |
| while (ip<ilimit) { |
| ip ++; |
| if ((offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) { |
| size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4; |
| int const gain2 = (int)(mlRep * 3); |
| int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1); |
| if ((mlRep >= 4) && (gain2 > gain1)) |
| matchLength = mlRep, offset = 0, start = ip; |
| } |
| { size_t offset2=99999999; |
| size_t const ml2 = searchMax(ms, cParams, ip, iend, &offset2); |
| int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ |
| int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4); |
| if ((ml2 >= 4) && (gain2 > gain1)) { |
| matchLength = ml2, offset = offset2, start = ip; |
| continue; /* search a better one */ |
| } } |
| |
| /* let's find an even better one */ |
| if ((depth==2) && (ip<ilimit)) { |
| ip ++; |
| if ((offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) { |
| size_t const ml2 = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4; |
| int const gain2 = (int)(ml2 * 4); |
| int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1); |
| if ((ml2 >= 4) && (gain2 > gain1)) |
| matchLength = ml2, offset = 0, start = ip; |
| } |
| { size_t offset2=99999999; |
| size_t const ml2 = searchMax(ms, cParams, ip, iend, &offset2); |
| int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ |
| int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7); |
| if ((ml2 >= 4) && (gain2 > gain1)) { |
| matchLength = ml2, offset = offset2, start = ip; |
| continue; |
| } } } |
| break; /* nothing found : store previous solution */ |
| } |
| |
| /* NOTE: |
| * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior. |
| * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which |
| * overflows the pointer, which is undefined behavior. |
| */ |
| /* catch up */ |
| if (offset) { |
| while ( ((start > anchor) & (start - (offset-ZSTD_REP_MOVE) > base)) |
| && (start[-1] == (start-(offset-ZSTD_REP_MOVE))[-1]) ) /* only search for offset within prefix */ |
| { start--; matchLength++; } |
| offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE); |
| } |
| /* store sequence */ |
| _storeSequence: |
| { size_t const litLength = start - anchor; |
| ZSTD_storeSeq(seqStore, litLength, anchor, (U32)offset, matchLength-MINMATCH); |
| anchor = ip = start + matchLength; |
| } |
| |
| /* check immediate repcode */ |
| while ( ((ip <= ilimit) & (offset_2>0)) |
| && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) { |
| /* store sequence */ |
| matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4; |
| offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap repcodes */ |
| ZSTD_storeSeq(seqStore, 0, anchor, 0, matchLength-MINMATCH); |
| ip += matchLength; |
| anchor = ip; |
| continue; /* faster when present ... (?) */ |
| } } |
| |
| /* Save reps for next block */ |
| rep[0] = offset_1 ? offset_1 : savedOffset; |
| rep[1] = offset_2 ? offset_2 : savedOffset; |
| |
| /* Return the last literals size */ |
| return iend - anchor; |
| } |
| |
| |
| size_t ZSTD_compressBlock_btlazy2( |
| 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_lazy_generic(ms, seqStore, rep, cParams, src, srcSize, 1, 2); |
| } |
| |
| size_t ZSTD_compressBlock_lazy2( |
| 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_lazy_generic(ms, seqStore, rep, cParams, src, srcSize, 0, 2); |
| } |
| |
| size_t ZSTD_compressBlock_lazy( |
| 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_lazy_generic(ms, seqStore, rep, cParams, src, srcSize, 0, 1); |
| } |
| |
| size_t ZSTD_compressBlock_greedy( |
| 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_lazy_generic(ms, seqStore, rep, cParams, src, srcSize, 0, 0); |
| } |
| |
| |
| FORCE_INLINE_TEMPLATE |
| size_t ZSTD_compressBlock_lazy_extDict_generic( |
| ZSTD_matchState_t* ms, seqStore_t* seqStore, |
| U32 rep[ZSTD_REP_NUM], |
| ZSTD_compressionParameters const* cParams, |
| const void* src, size_t srcSize, |
| const U32 searchMethod, const U32 depth) |
| { |
| 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 U32 dictLimit = ms->window.dictLimit; |
| const U32 lowestIndex = ms->window.lowLimit; |
| const BYTE* const prefixStart = base + dictLimit; |
| const BYTE* const dictBase = ms->window.dictBase; |
| const BYTE* const dictEnd = dictBase + dictLimit; |
| const BYTE* const dictStart = dictBase + lowestIndex; |
| |
| typedef size_t (*searchMax_f)( |
| ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, |
| const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr); |
| searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS_extDict : ZSTD_HcFindBestMatch_extDict_selectMLS; |
| |
| U32 offset_1 = rep[0], offset_2 = rep[1]; |
| |
| /* init */ |
| ms->nextToUpdate3 = ms->nextToUpdate; |
| ip += (ip == prefixStart); |
| |
| /* Match Loop */ |
| while (ip < ilimit) { |
| size_t matchLength=0; |
| size_t offset=0; |
| const BYTE* start=ip+1; |
| U32 current = (U32)(ip-base); |
| |
| /* check repCode */ |
| { const U32 repIndex = (U32)(current+1 - offset_1); |
| const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; |
| const BYTE* const repMatch = repBase + repIndex; |
| if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */ |
| if (MEM_read32(ip+1) == MEM_read32(repMatch)) { |
| /* repcode detected we should take it */ |
| const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; |
| matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4; |
| if (depth==0) goto _storeSequence; |
| } } |
| |
| /* first search (depth 0) */ |
| { size_t offsetFound = 99999999; |
| size_t const ml2 = searchMax(ms, cParams, ip, iend, &offsetFound); |
| if (ml2 > matchLength) |
| matchLength = ml2, start = ip, offset=offsetFound; |
| } |
| |
| if (matchLength < 4) { |
| ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */ |
| continue; |
| } |
| |
| /* let's try to find a better solution */ |
| if (depth>=1) |
| while (ip<ilimit) { |
| ip ++; |
| current++; |
| /* check repCode */ |
| if (offset) { |
| const U32 repIndex = (U32)(current - offset_1); |
| const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; |
| const BYTE* const repMatch = repBase + repIndex; |
| if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */ |
| if (MEM_read32(ip) == MEM_read32(repMatch)) { |
| /* repcode detected */ |
| const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; |
| size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4; |
| int const gain2 = (int)(repLength * 3); |
| int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1); |
| if ((repLength >= 4) && (gain2 > gain1)) |
| matchLength = repLength, offset = 0, start = ip; |
| } } |
| |
| /* search match, depth 1 */ |
| { size_t offset2=99999999; |
| size_t const ml2 = searchMax(ms, cParams, ip, iend, &offset2); |
| int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ |
| int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4); |
| if ((ml2 >= 4) && (gain2 > gain1)) { |
| matchLength = ml2, offset = offset2, start = ip; |
| continue; /* search a better one */ |
| } } |
| |
| /* let's find an even better one */ |
| if ((depth==2) && (ip<ilimit)) { |
| ip ++; |
| current++; |
| /* check repCode */ |
| if (offset) { |
| const U32 repIndex = (U32)(current - offset_1); |
| const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; |
| const BYTE* const repMatch = repBase + repIndex; |
| if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */ |
| if (MEM_read32(ip) == MEM_read32(repMatch)) { |
| /* repcode detected */ |
| const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; |
| size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4; |
| int const gain2 = (int)(repLength * 4); |
| int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1); |
| if ((repLength >= 4) && (gain2 > gain1)) |
| matchLength = repLength, offset = 0, start = ip; |
| } } |
| |
| /* search match, depth 2 */ |
| { size_t offset2=99999999; |
| size_t const ml2 = searchMax(ms, cParams, ip, iend, &offset2); |
| int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ |
| int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7); |
| if ((ml2 >= 4) && (gain2 > gain1)) { |
| matchLength = ml2, offset = offset2, start = ip; |
| continue; |
| } } } |
| break; /* nothing found : store previous solution */ |
| } |
| |
| /* catch up */ |
| if (offset) { |
| U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE)); |
| const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex; |
| const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart; |
| while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */ |
| offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE); |
| } |
| |
| /* store sequence */ |
| _storeSequence: |
| { size_t const litLength = start - anchor; |
| ZSTD_storeSeq(seqStore, litLength, anchor, (U32)offset, matchLength-MINMATCH); |
| anchor = ip = start + matchLength; |
| } |
| |
| /* check immediate repcode */ |
| while (ip <= ilimit) { |
| const U32 repIndex = (U32)((ip-base) - offset_2); |
| const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; |
| const BYTE* const repMatch = repBase + repIndex; |
| if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */ |
| if (MEM_read32(ip) == MEM_read32(repMatch)) { |
| /* repcode detected we should take it */ |
| const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; |
| matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4; |
| offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap offset history */ |
| ZSTD_storeSeq(seqStore, 0, anchor, 0, matchLength-MINMATCH); |
| ip += matchLength; |
| anchor = ip; |
| continue; /* faster when present ... (?) */ |
| } |
| break; |
| } } |
| |
| /* Save reps for next block */ |
| rep[0] = offset_1; |
| rep[1] = offset_2; |
| |
| /* Return the last literals size */ |
| return iend - anchor; |
| } |
| |
| |
| size_t ZSTD_compressBlock_greedy_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_lazy_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 0, 0); |
| } |
| |
| size_t ZSTD_compressBlock_lazy_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_lazy_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 0, 1); |
| } |
| |
| size_t ZSTD_compressBlock_lazy2_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_lazy_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 0, 2); |
| } |
| |
| size_t ZSTD_compressBlock_btlazy2_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_lazy_extDict_generic(ms, seqStore, rep, cParams, src, srcSize, 1, 2); |
| } |