754 lines
32 KiB
C
754 lines
32 KiB
C
/*
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* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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#include "zstd_lazy.h"
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/*-*************************************
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* Binary Tree search
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***************************************/
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/** ZSTD_insertBt1() : add one or multiple positions to tree.
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* ip : assumed <= iend-8 .
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* @return : nb of positions added */
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static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, const BYTE* const iend, U32 nbCompares,
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U32 extDict)
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{
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U32* const hashTable = zc->hashTable;
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U32 const hashLog = zc->appliedParams.cParams.hashLog;
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size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
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U32* const bt = zc->chainTable;
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U32 const btLog = zc->appliedParams.cParams.chainLog - 1;
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U32 const btMask = (1 << btLog) - 1;
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U32 matchIndex = hashTable[h];
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size_t commonLengthSmaller=0, commonLengthLarger=0;
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const BYTE* const base = zc->base;
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const BYTE* const dictBase = zc->dictBase;
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const U32 dictLimit = zc->dictLimit;
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const BYTE* const dictEnd = dictBase + dictLimit;
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const BYTE* const prefixStart = base + dictLimit;
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const BYTE* match;
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const U32 current = (U32)(ip-base);
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const U32 btLow = btMask >= current ? 0 : current - btMask;
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U32* smallerPtr = bt + 2*(current&btMask);
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U32* largerPtr = smallerPtr + 1;
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U32 dummy32; /* to be nullified at the end */
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U32 const windowLow = zc->lowLimit;
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U32 matchEndIdx = current+8;
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size_t bestLength = 8;
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#ifdef ZSTD_C_PREDICT
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U32 predictedSmall = *(bt + 2*((current-1)&btMask) + 0);
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U32 predictedLarge = *(bt + 2*((current-1)&btMask) + 1);
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predictedSmall += (predictedSmall>0);
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predictedLarge += (predictedLarge>0);
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#endif /* ZSTD_C_PREDICT */
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hashTable[h] = current; /* Update Hash Table */
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while (nbCompares-- && (matchIndex > windowLow)) {
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U32* const nextPtr = bt + 2*(matchIndex & btMask);
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size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
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#ifdef ZSTD_C_PREDICT /* note : can create issues when hlog small <= 11 */
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const U32* predictPtr = bt + 2*((matchIndex-1) & btMask); /* written this way, as bt is a roll buffer */
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if (matchIndex == predictedSmall) {
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/* no need to check length, result known */
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*smallerPtr = matchIndex;
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if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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smallerPtr = nextPtr+1; /* new "smaller" => larger of match */
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matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
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predictedSmall = predictPtr[1] + (predictPtr[1]>0);
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continue;
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}
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if (matchIndex == predictedLarge) {
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*largerPtr = matchIndex;
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if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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largerPtr = nextPtr;
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matchIndex = nextPtr[0];
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predictedLarge = predictPtr[0] + (predictPtr[0]>0);
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continue;
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}
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#endif
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if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
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match = base + matchIndex;
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if (match[matchLength] == ip[matchLength])
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matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
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} else {
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match = dictBase + matchIndex;
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matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
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if (matchIndex+matchLength >= dictLimit)
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match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
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}
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if (matchLength > bestLength) {
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bestLength = matchLength;
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if (matchLength > matchEndIdx - matchIndex)
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matchEndIdx = matchIndex + (U32)matchLength;
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}
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if (ip+matchLength == iend) /* equal : no way to know if inf or sup */
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break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt the tree */
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if (match[matchLength] < ip[matchLength]) { /* necessarily within correct buffer */
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/* match is smaller than current */
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*smallerPtr = matchIndex; /* update smaller idx */
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commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
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if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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smallerPtr = nextPtr+1; /* new "smaller" => larger of match */
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matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
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} else {
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/* match is larger than current */
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*largerPtr = matchIndex;
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commonLengthLarger = matchLength;
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if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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largerPtr = nextPtr;
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matchIndex = nextPtr[0];
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} }
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*smallerPtr = *largerPtr = 0;
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if (bestLength > 384) return MIN(192, (U32)(bestLength - 384)); /* speed optimization */
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if (matchEndIdx > current + 8) return matchEndIdx - current - 8;
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return 1;
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}
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static size_t ZSTD_insertBtAndFindBestMatch (
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ZSTD_CCtx* zc,
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const BYTE* const ip, const BYTE* const iend,
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size_t* offsetPtr,
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U32 nbCompares, const U32 mls,
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U32 extDict)
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{
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U32* const hashTable = zc->hashTable;
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U32 const hashLog = zc->appliedParams.cParams.hashLog;
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size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
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U32* const bt = zc->chainTable;
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U32 const btLog = zc->appliedParams.cParams.chainLog - 1;
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U32 const btMask = (1 << btLog) - 1;
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U32 matchIndex = hashTable[h];
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size_t commonLengthSmaller=0, commonLengthLarger=0;
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const BYTE* const base = zc->base;
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const BYTE* const dictBase = zc->dictBase;
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const U32 dictLimit = zc->dictLimit;
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const BYTE* const dictEnd = dictBase + dictLimit;
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const BYTE* const prefixStart = base + dictLimit;
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const U32 current = (U32)(ip-base);
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const U32 btLow = btMask >= current ? 0 : current - btMask;
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const U32 windowLow = zc->lowLimit;
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U32* smallerPtr = bt + 2*(current&btMask);
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U32* largerPtr = bt + 2*(current&btMask) + 1;
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U32 matchEndIdx = current+8;
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U32 dummy32; /* to be nullified at the end */
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size_t bestLength = 0;
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hashTable[h] = current; /* Update Hash Table */
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while (nbCompares-- && (matchIndex > windowLow)) {
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U32* const nextPtr = bt + 2*(matchIndex & btMask);
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size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
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const BYTE* match;
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if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
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match = base + matchIndex;
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if (match[matchLength] == ip[matchLength])
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matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
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} else {
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match = dictBase + matchIndex;
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matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
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if (matchIndex+matchLength >= dictLimit)
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match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
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}
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if (matchLength > bestLength) {
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if (matchLength > matchEndIdx - matchIndex)
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matchEndIdx = matchIndex + (U32)matchLength;
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if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
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bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
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if (ip+matchLength == iend) /* equal : no way to know if inf or sup */
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break; /* drop, to guarantee consistency (miss a little bit of compression) */
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}
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if (match[matchLength] < ip[matchLength]) {
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/* match is smaller than current */
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*smallerPtr = matchIndex; /* update smaller idx */
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commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
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if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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smallerPtr = nextPtr+1; /* new "smaller" => larger of match */
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matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */
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} else {
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/* match is larger than current */
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*largerPtr = matchIndex;
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commonLengthLarger = matchLength;
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if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */
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largerPtr = nextPtr;
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matchIndex = nextPtr[0];
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} }
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*smallerPtr = *largerPtr = 0;
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zc->nextToUpdate = (matchEndIdx > current + 8) ? matchEndIdx - 8 : current+1;
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return bestLength;
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}
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void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
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{
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const BYTE* const base = zc->base;
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const U32 target = (U32)(ip - base);
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U32 idx = zc->nextToUpdate;
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while(idx < target)
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idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0);
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}
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/** ZSTD_BtFindBestMatch() : Tree updater, providing best match */
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static size_t ZSTD_BtFindBestMatch (
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ZSTD_CCtx* zc,
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const BYTE* const ip, const BYTE* const iLimit,
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size_t* offsetPtr,
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const U32 maxNbAttempts, const U32 mls)
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{
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if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
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ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
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return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0);
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}
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static size_t ZSTD_BtFindBestMatch_selectMLS (
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ZSTD_CCtx* zc, /* Index table will be updated */
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const BYTE* ip, const BYTE* const iLimit,
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size_t* offsetPtr,
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const U32 maxNbAttempts, const U32 matchLengthSearch)
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{
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switch(matchLengthSearch)
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{
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default : /* includes case 3 */
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case 4 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
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case 5 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
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case 7 :
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case 6 : return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
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}
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}
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void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
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{
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const BYTE* const base = zc->base;
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const U32 target = (U32)(ip - base);
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U32 idx = zc->nextToUpdate;
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while (idx < target) idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 1);
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}
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/** Tree updater, providing best match */
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static size_t ZSTD_BtFindBestMatch_extDict (
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ZSTD_CCtx* zc,
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const BYTE* const ip, const BYTE* const iLimit,
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size_t* offsetPtr,
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const U32 maxNbAttempts, const U32 mls)
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{
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if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
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ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
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return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
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}
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static size_t ZSTD_BtFindBestMatch_selectMLS_extDict (
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ZSTD_CCtx* zc, /* Index table will be updated */
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const BYTE* ip, const BYTE* const iLimit,
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size_t* offsetPtr,
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const U32 maxNbAttempts, const U32 matchLengthSearch)
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{
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switch(matchLengthSearch)
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{
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default : /* includes case 3 */
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case 4 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
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case 5 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
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case 7 :
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case 6 : return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
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}
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}
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/* *********************************
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* Hash Chain
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***********************************/
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#define NEXT_IN_CHAIN(d, mask) chainTable[(d) & mask]
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/* Update chains up to ip (excluded)
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Assumption : always within prefix (i.e. not within extDict) */
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U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls)
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{
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U32* const hashTable = zc->hashTable;
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const U32 hashLog = zc->appliedParams.cParams.hashLog;
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U32* const chainTable = zc->chainTable;
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const U32 chainMask = (1 << zc->appliedParams.cParams.chainLog) - 1;
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const BYTE* const base = zc->base;
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const U32 target = (U32)(ip - base);
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U32 idx = zc->nextToUpdate;
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while(idx < target) { /* catch up */
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size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls);
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NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
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hashTable[h] = idx;
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idx++;
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}
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zc->nextToUpdate = target;
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return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
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}
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/* inlining is important to hardwire a hot branch (template emulation) */
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FORCE_INLINE_TEMPLATE
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size_t ZSTD_HcFindBestMatch_generic (
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ZSTD_CCtx* zc, /* Index table will be updated */
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const BYTE* const ip, const BYTE* const iLimit,
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size_t* offsetPtr,
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const U32 maxNbAttempts, const U32 mls, const U32 extDict)
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{
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U32* const chainTable = zc->chainTable;
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const U32 chainSize = (1 << zc->appliedParams.cParams.chainLog);
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const U32 chainMask = chainSize-1;
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const BYTE* const base = zc->base;
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const BYTE* const dictBase = zc->dictBase;
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const U32 dictLimit = zc->dictLimit;
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const BYTE* const prefixStart = base + dictLimit;
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const BYTE* const dictEnd = dictBase + 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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int nbAttempts=maxNbAttempts;
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size_t ml=4-1;
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/* HC4 match finder */
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U32 matchIndex = ZSTD_insertAndFindFirstIndex (zc, ip, mls);
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for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) {
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const BYTE* match;
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size_t currentMl=0;
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if ((!extDict) || matchIndex >= dictLimit) {
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match = base + matchIndex;
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if (match[ml] == ip[ml]) /* potentially better */
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currentMl = ZSTD_count(ip, match, iLimit);
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} else {
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match = dictBase + matchIndex;
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if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
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currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
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}
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/* save best solution */
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if (currentMl > ml) {
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ml = currentMl;
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*offsetPtr = current - matchIndex + ZSTD_REP_MOVE;
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if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
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}
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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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return ml;
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}
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FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
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ZSTD_CCtx* zc,
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const BYTE* ip, const BYTE* const iLimit,
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size_t* offsetPtr,
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const U32 maxNbAttempts, const U32 matchLengthSearch)
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{
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switch(matchLengthSearch)
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{
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default : /* includes case 3 */
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case 4 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 0);
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case 5 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 0);
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case 7 :
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case 6 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 0);
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}
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}
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FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
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ZSTD_CCtx* zc,
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const BYTE* ip, const BYTE* const iLimit,
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size_t* offsetPtr,
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const U32 maxNbAttempts, const U32 matchLengthSearch)
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{
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switch(matchLengthSearch)
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{
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default : /* includes case 3 */
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case 4 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 1);
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case 5 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 1);
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case 7 :
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case 6 : return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 1);
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}
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}
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/* *******************************
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* Common parser - lazy strategy
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*********************************/
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FORCE_INLINE_TEMPLATE
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void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx* ctx,
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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 + ctx->dictLimit;
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U32 const maxSearches = 1 << ctx->appliedParams.cParams.searchLog;
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U32 const mls = ctx->appliedParams.cParams.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 const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS;
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U32 offset_1 = seqStorePtr->rep[0], offset_2 = seqStorePtr->rep[1], savedOffset=0;
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/* init */
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ip += (ip==base);
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ctx->nextToUpdate3 = ctx->nextToUpdate;
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{ 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;
|
|
|
|
/* Last Literals */
|
|
{ size_t const lastLLSize = iend - anchor;
|
|
memcpy(seqStorePtr->lit, anchor, lastLLSize);
|
|
seqStorePtr->lit += lastLLSize;
|
|
}
|
|
}
|
|
|
|
|
|
void ZSTD_compressBlock_btlazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 1, 2);
|
|
}
|
|
|
|
void ZSTD_compressBlock_lazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 2);
|
|
}
|
|
|
|
void ZSTD_compressBlock_lazy(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 1);
|
|
}
|
|
|
|
void ZSTD_compressBlock_greedy(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 0);
|
|
}
|
|
|
|
|
|
FORCE_INLINE_TEMPLATE
|
|
void 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;
|
|
|
|
/* Last Literals */
|
|
{ size_t const lastLLSize = iend - anchor;
|
|
memcpy(seqStorePtr->lit, anchor, lastLLSize);
|
|
seqStorePtr->lit += lastLLSize;
|
|
}
|
|
}
|
|
|
|
|
|
void ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 0);
|
|
}
|
|
|
|
void ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 1);
|
|
}
|
|
|
|
void ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 2);
|
|
}
|
|
|
|
void ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 1, 2);
|
|
}
|