void ZSTD_fillHashTable(ZSTD_matchState_t* ms, ZSTD_compressionParameters const* cParams, void const* end, ZSTD_dictTableLoadMethod_e dtlm) { U32* const hashTable = ms->hashTable; U32 const hBits = cParams->hashLog; U32 const mls = cParams->searchLength; const BYTE* const base = ms->window.base; const BYTE* ip = base + ms->nextToUpdate; const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE; const U32 fastHashFillStep = 3; /* Always insert every fastHashFillStep position into the hash table. * Insert the other positions if their hash entry is empty. */ for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) { U32 const current = (U32)(ip - base); U32 i; for (i = 0; i < fastHashFillStep; ++i) { size_t const hash = ZSTD_hashPtr(ip + i, hBits, mls); if (i == 0 || hashTable[hash] == 0) hashTable[hash] = current + i; /* Only load extra positions for ZSTD_dtlm_full */ if (dtlm == ZSTD_dtlm_fast) break; } } }
void ZSTD_fillDoubleHashTable(ZSTD_CCtx* cctx, const void* end, const U32 mls) { U32* const hashLarge = cctx->hashTable; U32 const hBitsL = cctx->appliedParams.cParams.hashLog; U32* const hashSmall = cctx->chainTable; U32 const hBitsS = cctx->appliedParams.cParams.chainLog; const BYTE* const base = cctx->base; const BYTE* ip = base + cctx->nextToUpdate; const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE; const size_t fastHashFillStep = 3; while(ip <= iend) { hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip - base); hashLarge[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip - base); ip += fastHashFillStep; } }
/* Update chains up to ip (excluded) Assumption : always within prefix (i.e. not within extDict) */ U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls) { U32* const hashTable = zc->hashTable; const U32 hashLog = zc->appliedParams.cParams.hashLog; U32* const chainTable = zc->chainTable; const U32 chainMask = (1 << zc->appliedParams.cParams.chainLog) - 1; const BYTE* const base = zc->base; const U32 target = (U32)(ip - base); U32 idx = zc->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++; } zc->nextToUpdate = target; return hashTable[ZSTD_hashPtr(ip, hashLog, mls)]; }
/* Update chains up to ip (excluded) Assumption : always within prefix (i.e. not within extDict) */ static U32 ZSTD_insertAndFindFirstIndex_internal( ZSTD_matchState_t* ms, const 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)]; }
static void ZSTD_updateDUBT(ZSTD_matchState_t* ms, const BYTE* ip, const BYTE* iend, U32 mls) { const ZSTD_compressionParameters* const cParams = &ms->cParams; 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; }
/* inlining is important to hardwire a hot branch (template emulation) */ FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_generic ( ZSTD_matchState_t* ms, const BYTE* const ip, const BYTE* const iLimit, size_t* offsetPtr, const U32 mls, const ZSTD_dictMode_e dictMode) { const ZSTD_compressionParameters* const cParams = &ms->cParams; 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 ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) { const BYTE* const match = base + matchIndex; assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */ 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); } if (dictMode == ZSTD_dictMatchState) { const ZSTD_matchState_t* const dms = ms->dictMatchState; const U32* const dmsChainTable = dms->chainTable; const U32 dmsChainSize = (1 << dms->cParams.chainLog); const U32 dmsChainMask = dmsChainSize - 1; const U32 dmsLowestIndex = dms->window.dictLimit; const BYTE* const dmsBase = dms->window.base; const BYTE* const dmsEnd = dms->window.nextSrc; const U32 dmsSize = (U32)(dmsEnd - dmsBase); const U32 dmsIndexDelta = dictLimit - dmsSize; const U32 dmsMinChain = dmsSize > dmsChainSize ? dmsSize - dmsChainSize : 0; matchIndex = dms->hashTable[ZSTD_hashPtr(ip, dms->cParams.hashLog, mls)]; for ( ; (matchIndex>dmsLowestIndex) & (nbAttempts>0) ; nbAttempts--) { size_t currentMl=0; const BYTE* const match = dmsBase + matchIndex; assert(match+4 <= dmsEnd); if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */ currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4; /* save best solution */ if (currentMl > ml) { ml = currentMl; *offsetPtr = current - (matchIndex + dmsIndexDelta) + ZSTD_REP_MOVE; if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */ } if (matchIndex <= dmsMinChain) break; matchIndex = dmsChainTable[matchIndex & dmsChainMask]; } } return ml; }
static size_t ZSTD_DUBT_findBestMatch(ZSTD_matchState_t* ms, const BYTE* const ip, const BYTE* const iend, size_t* offsetPtr, U32 const mls, const ZSTD_dictMode_e dictMode) { 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 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; /* the unsortedMark becomes a reversed chain, to move up back to original position */ previousCandidate = matchIndex; matchIndex = *nextCandidate; nextCandidate = bt + 2*(matchIndex&btMask); unsortedMark = bt + 2*(matchIndex&btMask) + 1; nbCandidates --; } /* nullify last candidate if it's still unsorted * simplification, detrimental to compression ratio, beneficial for speed */ if ( (matchIndex > unsortLimit) && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) { DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u", matchIndex); *nextCandidate = *unsortedMark = 0; } /* 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, matchIndex, iend, nbCandidates, unsortLimit, dictMode); 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 ((dictMode != ZSTD_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 */ if (dictMode == ZSTD_dictMatchState) { nbCompares = 0; /* in addition to avoiding checking any * further in this loop, make sure we * skip checking in the dictionary. */ } 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; if (dictMode == ZSTD_dictMatchState && nbCompares) { bestLength = ZSTD_DUBT_findBetterDictMatch( ms, ip, iend, offsetPtr, bestLength, nbCompares, mls, dictMode); } 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; } }
static size_t ZSTD_DUBT_findBetterDictMatch ( ZSTD_matchState_t* ms, const BYTE* const ip, const BYTE* const iend, size_t* offsetPtr, size_t bestLength, U32 nbCompares, U32 const mls, const ZSTD_dictMode_e dictMode) { const ZSTD_matchState_t * const dms = ms->dictMatchState; const ZSTD_compressionParameters* const dmsCParams = &dms->cParams; const U32 * const dictHashTable = dms->hashTable; U32 const hashLog = dmsCParams->hashLog; size_t const h = ZSTD_hashPtr(ip, hashLog, mls); U32 dictMatchIndex = dictHashTable[h]; const BYTE* const base = ms->window.base; const BYTE* const prefixStart = base + ms->window.dictLimit; U32 const current = (U32)(ip-base); const BYTE* const dictBase = dms->window.base; const BYTE* const dictEnd = dms->window.nextSrc; U32 const dictHighLimit = (U32)(dms->window.nextSrc - dms->window.base); U32 const dictLowLimit = dms->window.lowLimit; U32 const dictIndexDelta = ms->window.lowLimit - dictHighLimit; U32* const dictBt = dms->chainTable; U32 const btLog = dmsCParams->chainLog - 1; U32 const btMask = (1 << btLog) - 1; U32 const btLow = (btMask >= dictHighLimit - dictLowLimit) ? dictLowLimit : dictHighLimit - btMask; size_t commonLengthSmaller=0, commonLengthLarger=0; (void)dictMode; assert(dictMode == ZSTD_dictMatchState); while (nbCompares-- && (dictMatchIndex > dictLowLimit)) { U32* const nextPtr = dictBt + 2*(dictMatchIndex & btMask); size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ const BYTE* match = dictBase + dictMatchIndex; matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart); if (dictMatchIndex+matchLength >= dictHighLimit) match = base + dictMatchIndex + dictIndexDelta; /* to prepare for next usage of match[matchLength] */ if (matchLength > bestLength) { U32 matchIndex = dictMatchIndex + dictIndexDelta; if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) { DEBUGLOG(9, "ZSTD_DUBT_findBetterDictMatch(%u) : found better match length %u -> %u and offsetCode %u -> %u (dictMatchIndex %u, matchIndex %u)", current, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, ZSTD_REP_MOVE + current - matchIndex, dictMatchIndex, matchIndex); bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex; } if (ip+matchLength == iend) { /* reached end of input : ip[matchLength] is not valid, no way to know if it's larger or smaller than match */ break; /* drop, to guarantee consistency (miss a little bit of compression) */ } } if (match[matchLength] < ip[matchLength]) { if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */ 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 */ if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */ commonLengthLarger = matchLength; dictMatchIndex = nextPtr[0]; } } if (bestLength >= MINMATCH) { U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex; DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)", current, (U32)bestLength, (U32)*offsetPtr, mIndex); } return bestLength; }
/** ZSTD_insertBt1() : add one or multiple positions to tree. * ip : assumed <= iend-8 . * @return : nb of positions added */ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, const BYTE* const iend, U32 nbCompares, U32 extDict) { U32* const hashTable = zc->hashTable; U32 const hashLog = zc->appliedParams.cParams.hashLog; size_t const h = ZSTD_hashPtr(ip, hashLog, mls); U32* const bt = zc->chainTable; U32 const btLog = zc->appliedParams.cParams.chainLog - 1; U32 const btMask = (1 << btLog) - 1; U32 matchIndex = hashTable[h]; size_t commonLengthSmaller=0, commonLengthLarger=0; const BYTE* const base = zc->base; const BYTE* const dictBase = zc->dictBase; const U32 dictLimit = zc->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 = zc->lowLimit; U32 matchEndIdx = current+8; size_t bestLength = 8; #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 */ 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 */ #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)) { match = base + matchIndex; if (match[matchLength] == ip[matchLength]) matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1; } 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+1 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 "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 searching */ largerPtr = nextPtr; matchIndex = nextPtr[0]; } } *smallerPtr = *largerPtr = 0; if (bestLength > 384) return MIN(192, (U32)(bestLength - 384)); /* speed optimization */ if (matchEndIdx > current + 8) return matchEndIdx - (current + 8); return 1; }
static size_t ZSTD_insertBtAndFindBestMatch ( ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, size_t* offsetPtr, U32 nbCompares, const U32 mls, U32 extDict) { U32* const hashTable = zc->hashTable; U32 const hashLog = zc->appliedParams.cParams.hashLog; size_t const h = ZSTD_hashPtr(ip, hashLog, mls); U32* const bt = zc->chainTable; U32 const btLog = zc->appliedParams.cParams.chainLog - 1; U32 const btMask = (1 << btLog) - 1; U32 matchIndex = hashTable[h]; size_t commonLengthSmaller=0, commonLengthLarger=0; const BYTE* const base = zc->base; const BYTE* const dictBase = zc->dictBase; const U32 dictLimit = zc->dictLimit; const BYTE* const dictEnd = dictBase + dictLimit; const BYTE* const prefixStart = base + dictLimit; const U32 current = (U32)(ip-base); const U32 btLow = btMask >= current ? 0 : current - btMask; const U32 windowLow = zc->lowLimit; U32* smallerPtr = bt + 2*(current&btMask); U32* largerPtr = bt + 2*(current&btMask) + 1; U32 matchEndIdx = current+8; U32 dummy32; /* to be nullified at the end */ size_t bestLength = 0; 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 */ const BYTE* match; if ((!extDict) || (matchIndex+matchLength >= dictLimit)) { match = base + matchIndex; if (match[matchLength] == ip[matchLength]) matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1; } 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; zc->nextToUpdate = (matchEndIdx > current + 8) ? matchEndIdx - 8 : current+1; return bestLength; }
FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx* cctx, const void* src, size_t srcSize, const U32 mls) { U32* const hashLong = cctx->hashTable; const U32 hBitsL = cctx->appliedParams.cParams.hashLog; U32* const hashSmall = cctx->chainTable; const U32 hBitsS = cctx->appliedParams.cParams.chainLog; seqStore_t* seqStorePtr = &(cctx->seqStore); const BYTE* const base = cctx->base; const BYTE* const istart = (const BYTE*)src; const BYTE* ip = istart; const BYTE* anchor = istart; const U32 lowestIndex = cctx->dictLimit; const BYTE* const lowest = base + lowestIndex; const BYTE* const iend = istart + srcSize; const BYTE* const ilimit = iend - HASH_READ_SIZE; U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1]; U32 offsetSaved = 0; /* init */ ip += (ip==lowest); { U32 const maxRep = (U32)(ip-lowest); if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0; if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0; } /* Main Search Loop */ while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */ size_t mLength; size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8); size_t const h = ZSTD_hashPtr(ip, hBitsS, mls); U32 const current = (U32)(ip-base); U32 const matchIndexL = hashLong[h2]; U32 const matchIndexS = hashSmall[h]; const BYTE* matchLong = base + matchIndexL; const BYTE* match = base + matchIndexS; hashLong[h2] = hashSmall[h] = current; /* update hash tables */ assert(offset_1 <= current); /* supposed guaranteed by construction */ if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) { /* favor repcode */ mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4; ip++; ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH); } else { U32 offset; if ( (matchIndexL > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip)) ) { mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8; offset = (U32)(ip-matchLong); while (((ip>anchor) & (matchLong>lowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */ } else if ( (matchIndexS > lowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) { size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8); U32 const matchIndexL3 = hashLong[hl3]; const BYTE* matchL3 = base + matchIndexL3; hashLong[hl3] = current + 1; if ( (matchIndexL3 > lowestIndex) && (MEM_read64(matchL3) == MEM_read64(ip+1)) ) { mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8; ip++; offset = (U32)(ip-matchL3); while (((ip>anchor) & (matchL3>lowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */ } else { mLength = ZSTD_count(ip+4, match+4, iend) + 4; offset = (U32)(ip-match); while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ } } else { ip += ((ip-anchor) >> g_searchStrength) + 1; continue; } offset_2 = offset_1; offset_1 = offset; ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); } /* match found */ ip += mLength; anchor = ip; if (ip <= ilimit) { /* Fill Table */ hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2; /* here because current+2 could be > iend-8 */ hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base); /* check immediate repcode */ while ( (ip <= ilimit) && ( (offset_2>0) & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) { /* store sequence */ size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4; { U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */ hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base); hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base); ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength-MINMATCH); ip += rLength; anchor = ip; continue; /* faster when present ... (?) */ } } } /* save reps for next block */ seqStorePtr->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved; seqStorePtr->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved; /* Return the last literals size */ return iend - anchor; }
static size_t ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_CCtx* ctx, const void* src, size_t srcSize, const U32 mls) { U32* const hashLong = ctx->hashTable; U32 const hBitsL = ctx->appliedParams.cParams.hashLog; U32* const hashSmall = ctx->chainTable; U32 const hBitsS = ctx->appliedParams.cParams.chainLog; seqStore_t* seqStorePtr = &(ctx->seqStore); const BYTE* const base = ctx->base; const BYTE* const dictBase = ctx->dictBase; const BYTE* const istart = (const BYTE*)src; const BYTE* ip = istart; const BYTE* anchor = istart; const U32 lowestIndex = ctx->lowLimit; const BYTE* const dictStart = dictBase + lowestIndex; const U32 dictLimit = ctx->dictLimit; const BYTE* const lowPrefixPtr = base + dictLimit; const BYTE* const dictEnd = dictBase + dictLimit; const BYTE* const iend = istart + srcSize; const BYTE* const ilimit = iend - 8; U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1]; /* Search Loop */ while (ip < ilimit) { /* < instead of <=, because (ip+1) */ const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls); const U32 matchIndex = hashSmall[hSmall]; const BYTE* matchBase = matchIndex < dictLimit ? dictBase : base; const BYTE* match = matchBase + matchIndex; const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8); const U32 matchLongIndex = hashLong[hLong]; const BYTE* matchLongBase = matchLongIndex < dictLimit ? dictBase : base; const BYTE* matchLong = matchLongBase + matchLongIndex; const U32 current = (U32)(ip-base); const U32 repIndex = current + 1 - offset_1; /* offset_1 expected <= current +1 */ const BYTE* repBase = repIndex < dictLimit ? dictBase : base; const BYTE* repMatch = repBase + repIndex; size_t mLength; hashSmall[hSmall] = hashLong[hLong] = current; /* update hash table */ if ( (((U32)((dictLimit-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex)) && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { const BYTE* repMatchEnd = repIndex < dictLimit ? dictEnd : iend; mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, lowPrefixPtr) + 4; ip++; ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH); } else { if ((matchLongIndex > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) { const BYTE* matchEnd = matchLongIndex < dictLimit ? dictEnd : iend; const BYTE* lowMatchPtr = matchLongIndex < dictLimit ? dictStart : lowPrefixPtr; U32 offset; mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, lowPrefixPtr) + 8; offset = current - matchLongIndex; while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */ offset_2 = offset_1; offset_1 = offset; ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); } else if ((matchIndex > lowestIndex) && (MEM_read32(match) == MEM_read32(ip))) { size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8); U32 const matchIndex3 = hashLong[h3]; const BYTE* const match3Base = matchIndex3 < dictLimit ? dictBase : base; const BYTE* match3 = match3Base + matchIndex3; U32 offset; hashLong[h3] = current + 1; if ( (matchIndex3 > lowestIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) { const BYTE* matchEnd = matchIndex3 < dictLimit ? dictEnd : iend; const BYTE* lowMatchPtr = matchIndex3 < dictLimit ? dictStart : lowPrefixPtr; mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, lowPrefixPtr) + 8; ip++; offset = current+1 - matchIndex3; while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */ } else { const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend; const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr; mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4; offset = current - matchIndex; while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ } offset_2 = offset_1; offset_1 = offset; ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); } else { ip += ((ip-anchor) >> g_searchStrength) + 1; continue; } } /* found a match : store it */ ip += mLength; anchor = ip; if (ip <= ilimit) { /* Fill Table */ hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2; hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = current+2; hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base); hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base); /* check immediate repcode */ while (ip <= ilimit) { U32 const current2 = (U32)(ip-base); U32 const repIndex2 = current2 - offset_2; const BYTE* repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2; if ( (((U32)((dictLimit-1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */ && (MEM_read32(repMatch2) == MEM_read32(ip)) ) { const BYTE* const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend; size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, lowPrefixPtr) + 4; U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */ ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2-MINMATCH); hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2; hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2; ip += repLength2; anchor = ip; continue; } break; } } } /* save reps for next block */ seqStorePtr->repToConfirm[0] = offset_1; seqStorePtr->repToConfirm[1] = offset_2; /* Return the last literals size */ return iend - anchor; }
FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_fast_generic( ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], void const* src, size_t srcSize, U32 const hlog, U32 const stepSize, U32 const mls) { U32* const hashTable = ms->hashTable; const BYTE* const base = ms->window.base; const BYTE* const istart = (const BYTE*)src; const BYTE* ip = istart; const BYTE* anchor = istart; const U32 lowestIndex = ms->window.dictLimit; const BYTE* const lowest = base + lowestIndex; const BYTE* const iend = istart + srcSize; const BYTE* const ilimit = iend - HASH_READ_SIZE; U32 offset_1=rep[0], offset_2=rep[1]; U32 offsetSaved = 0; /* init */ ip += (ip==lowest); { U32 const maxRep = (U32)(ip-lowest); if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0; if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0; } /* Main Search Loop */ while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */ size_t mLength; size_t const h = ZSTD_hashPtr(ip, hlog, mls); U32 const current = (U32)(ip-base); U32 const matchIndex = hashTable[h]; const BYTE* match = base + matchIndex; hashTable[h] = current; /* update hash table */ if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) { mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4; ip++; ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); } else { if ( (matchIndex <= lowestIndex) || (MEM_read32(match) != MEM_read32(ip)) ) { assert(stepSize >= 1); ip += ((ip-anchor) >> kSearchStrength) + stepSize; continue; } mLength = ZSTD_count(ip+4, match+4, iend) + 4; { U32 const offset = (U32)(ip-match); while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ offset_2 = offset_1; offset_1 = offset; ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); } } /* match found */ ip += mLength; anchor = ip; if (ip <= ilimit) { /* Fill Table */ hashTable[ZSTD_hashPtr(base+current+2, hlog, mls)] = current+2; /* here because current+2 could be > iend-8 */ hashTable[ZSTD_hashPtr(ip-2, hlog, mls)] = (U32)(ip-2-base); /* check immediate repcode */ while ( (ip <= ilimit) && ( (offset_2>0) & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) { /* store sequence */ size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4; { U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */ hashTable[ZSTD_hashPtr(ip, hlog, mls)] = (U32)(ip-base); ZSTD_storeSeq(seqStore, 0, anchor, 0, rLength-MINMATCH); ip += rLength; anchor = ip; continue; /* faster when present ... (?) */ } } }