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Diffstat (limited to 'lib/compress/zstd_lazy.c')
| -rw-r--r-- | lib/compress/zstd_lazy.c | 749 |
1 files changed, 749 insertions, 0 deletions
diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c new file mode 100644 index 000000000000..2a7f6a0fe2be --- /dev/null +++ b/lib/compress/zstd_lazy.c @@ -0,0 +1,749 @@ +/* + * 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_lazy.h" + + +/*-************************************* +* 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_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; +} + + +void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls) +{ + const BYTE* const base = zc->base; + const U32 target = (U32)(ip - base); + U32 idx = zc->nextToUpdate; + + while(idx < target) + idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0); +} + +/** ZSTD_BtFindBestMatch() : Tree updater, providing best match */ +static size_t ZSTD_BtFindBestMatch ( + ZSTD_CCtx* zc, + const BYTE* const ip, const BYTE* const iLimit, + size_t* offsetPtr, + const U32 maxNbAttempts, const U32 mls) +{ + if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */ + ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls); + return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0); +} + + +static size_t ZSTD_BtFindBestMatch_selectMLS ( + ZSTD_CCtx* zc, /* Index table will be updated */ + const BYTE* ip, const BYTE* const iLimit, + size_t* offsetPtr, + const U32 maxNbAttempts, const U32 matchLengthSearch) +{ + switch(matchLengthSearch) + { + default : /* includes case 3 */ + case 4 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4); + case 5 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5); + case 7 : + case 6 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6); + } +} + + +void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls) +{ + const BYTE* const base = zc->base; + const U32 target = (U32)(ip - base); + U32 idx = zc->nextToUpdate; + + while (idx < target) idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 1); +} + + +/** Tree updater, providing best match */ +static size_t ZSTD_BtFindBestMatch_extDict ( + ZSTD_CCtx* zc, + const BYTE* const ip, const BYTE* const iLimit, + size_t* offsetPtr, + const U32 maxNbAttempts, const U32 mls) +{ + if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */ + ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls); + return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1); +} + + +static size_t ZSTD_BtFindBestMatch_selectMLS_extDict ( + ZSTD_CCtx* zc, /* Index table will be updated */ + const BYTE* ip, const BYTE* const iLimit, + size_t* offsetPtr, + const U32 maxNbAttempts, const U32 matchLengthSearch) +{ + switch(matchLengthSearch) + { + default : /* includes case 3 */ + case 4 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4); + case 5 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5); + case 7 : + case 6 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 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) */ +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)]; +} + + +/* inlining is important to hardwire a hot branch (template emulation) */ +FORCE_INLINE_TEMPLATE +size_t ZSTD_HcFindBestMatch_generic ( + ZSTD_CCtx* zc, /* Index table will be updated */ + const BYTE* const ip, const BYTE* const iLimit, + size_t* offsetPtr, + const U32 maxNbAttempts, const U32 mls, const U32 extDict) +{ + U32* const chainTable = zc->chainTable; + const U32 chainSize = (1 << zc->appliedParams.cParams.chainLog); + const U32 chainMask = chainSize-1; + const BYTE* const base = zc->base; + const BYTE* const dictBase = zc->dictBase; + const U32 dictLimit = zc->dictLimit; + const BYTE* const prefixStart = base + dictLimit; + const BYTE* const dictEnd = dictBase + dictLimit; + const U32 lowLimit = zc->lowLimit; + const U32 current = (U32)(ip-base); + const U32 minChain = current > chainSize ? current - chainSize : 0; + int nbAttempts=maxNbAttempts; + size_t ml=4-1; + + /* HC4 match finder */ + U32 matchIndex = ZSTD_insertAndFindFirstIndex (zc, ip, mls); + + for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) { + const BYTE* match; + size_t currentMl=0; + if ((!extDict) || matchIndex >= dictLimit) { + match = base + matchIndex; + if (match[ml] == ip[ml]) /* potentially better */ + currentMl = ZSTD_count(ip, match, iLimit); + } else { + match = dictBase + matchIndex; + 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_CCtx* zc, + const BYTE* ip, const BYTE* const iLimit, + size_t* offsetPtr, + const U32 maxNbAttempts, const U32 matchLengthSearch) +{ + switch(matchLengthSearch) + { + default : /* includes case 3 */ + case 4 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 0); + case 5 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 0); + case 7 : + case 6 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 0); + } +} + + +FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS ( + ZSTD_CCtx* zc, + const BYTE* ip, const BYTE* const iLimit, + size_t* offsetPtr, + const U32 maxNbAttempts, const U32 matchLengthSearch) +{ + switch(matchLengthSearch) + { + default : /* includes case 3 */ + case 4 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 1); + case 5 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 1); + case 7 : + case 6 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 1); + } +} + + +/* ******************************* +* Common parser - lazy strategy +*********************************/ +FORCE_INLINE_TEMPLATE +size_t ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx, + const void* src, size_t srcSize, + const U32 searchMethod, const U32 depth) +{ + seqStore_t* seqStorePtr = &(ctx->seqStore); + 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 = ctx->base + ctx->dictLimit; + + U32 const maxSearches = 1 << ctx->appliedParams.cParams.searchLog; + U32 const mls = ctx->appliedParams.cParams.searchLength; + + typedef size_t (*searchMax_f)(ZSTD_CCtx* zc, const BYTE* ip, const BYTE* iLimit, + size_t* offsetPtr, + U32 maxNbAttempts, U32 matchLengthSearch); + searchMax_f const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS; + U32 offset_1 = seqStorePtr->rep[0], offset_2 = seqStorePtr->rep[1], savedOffset=0; + + /* init */ + ip += (ip==base); + ctx->nextToUpdate3 = ctx->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(ctx, ip, iend, &offsetFound, maxSearches, mls); + if (ml2 > matchLength) + matchLength = ml2, start = ip, offset=offsetFound; + } + + if (matchLength < 4) { + ip += ((ip-anchor) >> g_searchStrength) + 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(ctx, ip, iend, &offset2, maxSearches, mls); + 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(ctx, ip, iend, &offset2, maxSearches, mls); + 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 > base+offset-ZSTD_REP_MOVE) + && (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(seqStorePtr, 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(seqStorePtr, 0, anchor, 0, matchLength-MINMATCH); + ip += matchLength; + anchor = ip; + continue; /* faster when present ... (?) */ + } } + + /* Save reps for next block */ + seqStorePtr->repToConfirm[0] = offset_1 ? offset_1 : savedOffset; + seqStorePtr->repToConfirm[1] = offset_2 ? offset_2 : savedOffset; + + /* Return the last literals size */ + return iend - anchor; +} + + +size_t ZSTD_compressBlock_btlazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 1, 2); +} + +size_t ZSTD_compressBlock_lazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 2); +} + +size_t ZSTD_compressBlock_lazy(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 1); +} + +size_t ZSTD_compressBlock_greedy(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 0); +} + + +FORCE_INLINE_TEMPLATE +size_t ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx, + const void* src, size_t srcSize, + const U32 searchMethod, const U32 depth) +{ + seqStore_t* seqStorePtr = &(ctx->seqStore); + 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 = ctx->base; + const U32 dictLimit = ctx->dictLimit; + const U32 lowestIndex = ctx->lowLimit; + const BYTE* const prefixStart = base + dictLimit; + const BYTE* const dictBase = ctx->dictBase; + const BYTE* const dictEnd = dictBase + dictLimit; + const BYTE* const dictStart = dictBase + ctx->lowLimit; + + const U32 maxSearches = 1 << ctx->appliedParams.cParams.searchLog; + const U32 mls = ctx->appliedParams.cParams.searchLength; + + typedef size_t (*searchMax_f)(ZSTD_CCtx* zc, const BYTE* ip, const BYTE* iLimit, + size_t* offsetPtr, + U32 maxNbAttempts, U32 matchLengthSearch); + searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS_extDict : ZSTD_HcFindBestMatch_extDict_selectMLS; + + U32 offset_1 = seqStorePtr->rep[0], offset_2 = seqStorePtr->rep[1]; + + /* init */ + ctx->nextToUpdate3 = ctx->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(ctx, ip, iend, &offsetFound, maxSearches, mls); + if (ml2 > matchLength) + matchLength = ml2, start = ip, offset=offsetFound; + } + + if (matchLength < 4) { + ip += ((ip-anchor) >> g_searchStrength) + 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(ctx, ip, iend, &offset2, maxSearches, mls); + 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(ctx, ip, iend, &offset2, maxSearches, mls); + 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(seqStorePtr, 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(seqStorePtr, 0, anchor, 0, matchLength-MINMATCH); + ip += matchLength; + anchor = ip; + continue; /* faster when present ... (?) */ + } + break; + } } + + /* Save reps for next block */ + seqStorePtr->repToConfirm[0] = offset_1; seqStorePtr->repToConfirm[1] = offset_2; + + /* Return the last literals size */ + return iend - anchor; +} + + +size_t ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 0); +} + +size_t ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 1); +} + +size_t ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 2); +} + +size_t ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize) +{ + return ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 1, 2); +} |