mirror of
https://github.com/facebook/zstd.git
synced 2024-12-15 17:20:07 +08:00
fixed roll buffer in fast mode
This commit is contained in:
Yann Collet
parent
007c1c6ff0
commit
9a24e5986b
@ -884,10 +884,11 @@ size_t ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
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&& (MEM_read32(repMatch) == MEM_read32(ip+1)) )
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{
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const BYTE* repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
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const BYTE* iEndCount = (repMatchEnd - repMatch < iend - ip - 1) ? ip + 1 + (repMatchEnd - repMatch) : iend;
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matchLength = ZSTD_count(ip+1+MINMATCH, repMatch+MINMATCH, iEndCount);
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if (match + matchLength + MINMATCH == dictEnd)
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matchLength += ZSTD_count(ip + matchLength + MINMATCH, lowPrefixPtr, iend);
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const BYTE* vEnd = ip+1 + (repMatchEnd-repMatch);
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if (vEnd > iend) vEnd = iend;
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matchLength = ZSTD_count(ip+1+MINMATCH, repMatch+MINMATCH, vEnd);
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if (repMatch + matchLength + MINMATCH == dictEnd)
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matchLength += ZSTD_count(ip+1 + matchLength + MINMATCH, lowPrefixPtr, iend);
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ip++;
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offset = 0;
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}
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@ -1128,7 +1129,6 @@ static const BYTE* ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BY
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for( ; idx < target ; )
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idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares);
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//ZSTD_insertBtAndFindBestMatch(zc, base+idx, iend, &dummy, nbCompares, mls);
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zc->nextToUpdate = idx;
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return base + idx;
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@ -1214,6 +1214,8 @@ size_t ZSTD_HcFindBestMatch (
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const BYTE* const dictBase = zc->dictBase;
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const U32 dictLimit = zc->dictLimit;
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const U32 lowLimit = zc->lowLimit;
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const U32 current = (U32)(ip-base);
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const U32 minChain = current > chainSize ? current - chainSize : 0;
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U32 matchIndex;
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const BYTE* match;
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int nbAttempts=maxNbAttempts;
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@ -1242,19 +1244,19 @@ size_t ZSTD_HcFindBestMatch (
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else
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{
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match = dictBase + matchIndex;
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if (MEM_read32(match) == MEM_read32(ip)) /* beware of end of dict */
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if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 */
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{
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size_t mlt;
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const BYTE* vLimit = ip + (dictLimit - matchIndex);
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if (vLimit > iLimit) vLimit = iLimit;
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mlt = ZSTD_count(ip+MINMATCH, match+MINMATCH, vLimit) + MINMATCH;
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if ((ip+mlt == vLimit) && (vLimit < iLimit))
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if (match+mlt == dictBase+dictLimit)
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mlt += ZSTD_count(ip+mlt, base+dictLimit, iLimit);
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if (mlt > ml) { ml = mlt; *offsetPtr = (ip-base) - matchIndex; }
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if (mlt > ml) { ml = mlt; *offsetPtr = current - matchIndex; }
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}
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}
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if (base + matchIndex <= ip - chainSize) break;
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if (matchIndex <= minChain) break;
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matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
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}
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@ -1278,7 +1280,9 @@ FORCE_INLINE size_t ZSTD_HcFindBestMatch_selectMLS (
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}
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/* common lazy function, to be inlined */
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/* ******************************
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* Common parser - lazy strategy
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********************************/
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FORCE_INLINE
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size_t ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
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void* dst, size_t maxDstSize, const void* src, size_t srcSize,
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@ -1320,16 +1324,17 @@ size_t ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
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}
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{
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/* search first solution */
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/* first search (depth 0) */
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size_t offsetFound = 99999999;
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size_t ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
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if (ml2 > matchLength)
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matchLength = ml2, start = ip, offset=offsetFound;
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if (matchLength < MINMATCH)
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{
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ip += ((ip-anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
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continue;
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}
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matchLength = ml2, start = ip, offset=offsetFound;
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}
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if (matchLength < MINMATCH)
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{
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ip += ((ip-anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
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continue;
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}
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/* let's try to find a better solution */
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@ -1387,7 +1392,7 @@ size_t ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
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/* catch up */
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if (offset)
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{
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while ((start>anchor) && (start>ctx->base+offset) && (start[-1] == start[-1-offset]))
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while ((start>anchor) && (start>ctx->base+offset) && (start[-1] == start[-1-offset])) /* only search for offset within prefix */
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{ start--; matchLength++; }
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offset_2 = offset_1; offset_1 = offset;
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}
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@ -1449,6 +1454,227 @@ size_t ZSTD_compressBlock_greedy(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, c
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}
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FORCE_INLINE
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size_t ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx* ctx,
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void* dst, size_t maxDstSize, const void* src, size_t srcSize,
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const U32 searchMethod, const U32 depth)
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{
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seqStore_t* seqStorePtr = &(ctx->seqStore);
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const BYTE* const istart = (const BYTE*)src;
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const BYTE* ip = istart;
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const BYTE* anchor = istart;
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const BYTE* const iend = istart + srcSize;
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const BYTE* const ilimit = iend - 8;
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const BYTE* const base = ctx->base;
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const U32 dictLimit = ctx->dictLimit;
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const BYTE* const prefixStart = base + dictLimit;
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const BYTE* const dictBase = ctx->dictBase;
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const BYTE* const dictEnd = dictBase + dictLimit;
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size_t offset_2=REPCODE_STARTVALUE, offset_1=REPCODE_STARTVALUE;
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const U32 maxSearches = 1 << ctx->params.searchLog;
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const U32 mls = ctx->params.searchLength;
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typedef size_t (*searchMax_f)(ZSTD_CCtx* zc, const BYTE* ip, const BYTE* iLimit,
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size_t* offsetPtr,
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U32 maxNbAttempts, U32 matchLengthSearch);
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searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS;
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/* init */
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ZSTD_resetSeqStore(seqStorePtr);
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if (((ip-base) - dictLimit) < REPCODE_STARTVALUE) ip += REPCODE_STARTVALUE;
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/* Match Loop */
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while (ip < ilimit)
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{
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size_t matchLength=0;
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size_t offset=0;
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const BYTE* start=ip+1;
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U32 current = (U32)(ip-base);
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/* check repCode */
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{
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const U32 repIndex = (U32)(current+1 - offset_1);
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const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
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const BYTE* const repMatch = repBase + repIndex;
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if (MEM_read32(ip+1) == MEM_read32(repMatch))
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{
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/* repcode detected we should take it */
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const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
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const BYTE* vEnd = ip+1 + (repEnd - repMatch);
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if (vEnd > iend) vEnd = iend;
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matchLength = ZSTD_count(ip+1+MINMATCH, repMatch+MINMATCH, vEnd) + MINMATCH;
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if (repMatch + matchLength == dictEnd)
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matchLength += ZSTD_count(ip+1+matchLength, prefixStart, iend);
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if (depth==0) goto _storeSequence;
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}
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}
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{
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/* first search (depth 0) */
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size_t offsetFound = 99999999;
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size_t ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
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if (ml2 > matchLength)
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matchLength = ml2, start = ip, offset=offsetFound;
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}
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if (matchLength < MINMATCH)
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{
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ip += ((ip-anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
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continue;
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}
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/* let's try to find a better solution */
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if (depth>=1)
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while (ip<ilimit)
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{
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ip ++;
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current++;
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/* check repCode */
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if (offset)
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{
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const U32 repIndex = (U32)(current - offset_1);
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const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
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const BYTE* const repMatch = repBase + repIndex;
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if (MEM_read32(ip) == MEM_read32(repMatch))
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{
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/* repcode detected */
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size_t repLength;
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const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
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const BYTE* vEnd = ip + (repEnd - repMatch);
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if (vEnd > iend) vEnd = iend;
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repLength = ZSTD_count(ip+MINMATCH, repMatch+MINMATCH, vEnd) + MINMATCH;
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if (repMatch + repLength == dictEnd)
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repLength += ZSTD_count(ip+repLength, prefixStart, iend);
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{
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int gain2 = (int)(repLength * 3);
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int gain1 = (int)(matchLength*3 - ZSTD_highbit((U32)offset+1) + 1);
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if ((repLength >= MINMATCH) && (gain2 > gain1))
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matchLength = repLength, offset = 0, start = ip;
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}
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}
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}
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/* search match, depth 1 */
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{
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size_t offset2=999999;
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size_t ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
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int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
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int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 4);
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if ((ml2 >= MINMATCH) && (gain2 > gain1))
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{
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matchLength = ml2, offset = offset2, start = ip;
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continue; /* search a better one */
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}
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}
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/* let's find an even better one */
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if ((depth==2) && (ip<ilimit))
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{
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ip ++;
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current++;
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/* check repCode */
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if (offset)
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{
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const U32 repIndex = (U32)(current - offset_1);
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const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
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const BYTE* const repMatch = repBase + repIndex;
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if (MEM_read32(ip) == MEM_read32(repMatch))
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{
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/* repcode detected */
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size_t repLength;
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const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
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const BYTE* vEnd = ip + (repEnd - repMatch);
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if (vEnd > iend) vEnd = iend;
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repLength = ZSTD_count(ip+MINMATCH, repMatch+MINMATCH, vEnd) + MINMATCH;
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if (repMatch + repLength == dictEnd)
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repLength += ZSTD_count(ip+repLength, prefixStart, iend);
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{
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int gain2 = (int)(repLength * 4);
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int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 1);
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if ((repLength >= MINMATCH) && (gain2 > gain1))
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matchLength = repLength, offset = 0, start = ip;
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}
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}
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}
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/* search match, depth 2 */
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{
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size_t offset2=999999;
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size_t ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
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int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
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int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 7);
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if ((ml2 >= MINMATCH) && (gain2 > gain1))
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{
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matchLength = ml2, offset = offset2, start = ip;
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continue;
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}
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}
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}
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break; /* nothing found : store previous solution */
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}
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/* catch up */
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if (offset)
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{
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while ((start>anchor) && (start>prefixStart+offset) && (start[-1] == start[-1-offset])) /* only search for offset within prefix */
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{ start--; matchLength++; }
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offset_2 = offset_1; offset_1 = offset;
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}
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/* store sequence */
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_storeSequence:
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{
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size_t litLength = start - anchor;
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ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, matchLength-MINMATCH);
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anchor = ip = start + matchLength;
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}
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/* check immediate repcode */
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while (ip <= ilimit)
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{
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const U32 repIndex = (U32)((ip-base) - offset_2);
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const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
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const BYTE* const repMatch = repBase + repIndex;
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if (MEM_read32(ip) == MEM_read32(repMatch))
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{
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/* repcode detected we should take it */
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const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
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const BYTE* vEnd = ip + (repEnd - repMatch);
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if (vEnd > iend) vEnd = iend;
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matchLength = ZSTD_count(ip+MINMATCH, repMatch+MINMATCH, vEnd) + MINMATCH;
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if (repMatch + matchLength == dictEnd)
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matchLength += ZSTD_count(ip+matchLength, prefixStart, iend);
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offset = offset_2;
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offset_2 = offset_1;
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offset_1 = offset;
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ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength-MINMATCH);
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ip += matchLength;
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anchor = ip;
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continue; /* faster when present ... (?) */
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}
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break;
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}
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}
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/* Last Literals */
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{
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size_t lastLLSize = iend - anchor;
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memcpy(seqStorePtr->lit, anchor, lastLLSize);
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seqStorePtr->lit += lastLLSize;
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}
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/* Final compression stage */
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return ZSTD_compressSequences((BYTE*)dst, maxDstSize,
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seqStorePtr, srcSize);
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}
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size_t ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
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{
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return ZSTD_compressBlock_lazy_extDict_generic(ctx, dst, maxDstSize, src, srcSize, 0, 0);
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}
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typedef size_t (*ZSTD_blockCompressor) (ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
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@ -1462,7 +1688,7 @@ static ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int
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case ZSTD_fast:
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return ZSTD_compressBlock_fast_extDict;
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case ZSTD_greedy:
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return ZSTD_compressBlock_greedy;
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return ZSTD_compressBlock_greedy_extDict;
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case ZSTD_lazy:
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return ZSTD_compressBlock_lazy;
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case ZSTD_lazy2:
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