FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/zstd/lib/compress/zstd_lazy.c

     /*
      * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
      * All rights reserved.
      *
      * This source code is licensed under both the BSD-style license (found in the
      * LICENSE file in the root directory of this source tree) and the GPLv2 (found
      * in the COPYING file in the root directory of this source tree).
      * You may select, at your option, one of the above-listed licenses.
      */
    
    #include "zstd_compress_internal.h"
    #include "zstd_lazy.h"
    
    
    /*-*************************************
    *  Binary Tree search
    ***************************************/
    
    static void
    ZSTD_updateDUBT(ZSTD_matchState_t* ms,
                    const BYTE* ip, const BYTE* iend,
                    U32 mls)
    {
        const ZSTD_compressionParameters* const cParams = &ms->cParams;
        U32* const hashTable = ms->hashTable;
        U32  const hashLog = cParams->hashLog;
    
        U32* const bt = ms->chainTable;
        U32  const btLog  = cParams->chainLog - 1;
        U32  const btMask = (1 << btLog) - 1;
    
        const BYTE* const base = ms->window.base;
        U32 const target = (U32)(ip - base);
        U32 idx = ms->nextToUpdate;
    
        if (idx != target)
            DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)",
                        idx, target, ms->window.dictLimit);
        assert(ip + 8 <= iend);   /* condition for ZSTD_hashPtr */
        (void)iend;
    
        assert(idx >= ms->window.dictLimit);   /* condition for valid base+idx */
        for ( ; idx < target ; idx++) {
            size_t const h  = ZSTD_hashPtr(base + idx, hashLog, mls);   /* assumption : ip + 8 <= iend */
            U32    const matchIndex = hashTable[h];
    
            U32*   const nextCandidatePtr = bt + 2*(idx&btMask);
            U32*   const sortMarkPtr  = nextCandidatePtr + 1;
    
            DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx);
            hashTable[h] = idx;   /* Update Hash Table */
            *nextCandidatePtr = matchIndex;   /* update BT like a chain */
            *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK;
        }
        ms->nextToUpdate = target;
    }
    
    
    /** ZSTD_insertDUBT1() :
     *  sort one already inserted but unsorted position
     *  assumption : current >= btlow == (current - btmask)
     *  doesn't fail */
    static void
    ZSTD_insertDUBT1(ZSTD_matchState_t* ms,
                     U32 current, const BYTE* inputEnd,
                     U32 nbCompares, U32 btLow,
                     const ZSTD_dictMode_e dictMode)
    {
        const ZSTD_compressionParameters* const cParams = &ms->cParams;
        U32* const bt = ms->chainTable;
        U32  const btLog  = cParams->chainLog - 1;
        U32  const btMask = (1 << btLog) - 1;
        size_t commonLengthSmaller=0, commonLengthLarger=0;
        const BYTE* const base = ms->window.base;
        const BYTE* const dictBase = ms->window.dictBase;
        const U32 dictLimit = ms->window.dictLimit;
        const BYTE* const ip = (current>=dictLimit) ? base + current : dictBase + current;
        const BYTE* const iend = (current>=dictLimit) ? inputEnd : dictBase + dictLimit;
        const BYTE* const dictEnd = dictBase + dictLimit;
        const BYTE* const prefixStart = base + dictLimit;
        const BYTE* match;
        U32* smallerPtr = bt + 2*(current&btMask);
        U32* largerPtr  = smallerPtr + 1;
        U32 matchIndex = *smallerPtr;   /* this candidate is unsorted : next sorted candidate is reached through *smallerPtr, while *largerPtr contains previous unsorted candidate (which is already saved and can be overwritten) */
        U32 dummy32;   /* to be nullified at the end */
        U32 const windowValid = ms->window.lowLimit;
        U32 const maxDistance = 1U << cParams->windowLog;
        U32 const windowLow = (current - windowValid > maxDistance) ? current - maxDistance : windowValid;
    
    
        DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)",
                    current, dictLimit, windowLow);
        assert(current >= btLow);
        assert(ip < iend);   /* condition for ZSTD_count */
    
        while (nbCompares-- && (matchIndex > windowLow)) {
            U32* const nextPtr = bt + 2*(matchIndex & btMask);
            size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
            assert(matchIndex < current);
           /* note : all candidates are now supposed sorted,
            * but it's still possible to have nextPtr[1] == ZSTD_DUBT_UNSORTED_MARK
            * when a real index has the same value as ZSTD_DUBT_UNSORTED_MARK */
   
           if ( (dictMode != ZSTD_extDict)
             || (matchIndex+matchLength >= dictLimit)  /* both in current segment*/
             || (current < dictLimit) /* both in extDict */) {
               const BYTE* const mBase = ( (dictMode != ZSTD_extDict)
                                        || (matchIndex+matchLength >= dictLimit)) ?
                                           base : dictBase;
               assert( (matchIndex+matchLength >= dictLimit)   /* might be wrong if extDict is incorrectly set to 0 */
                    || (current < dictLimit) );
               match = mBase + matchIndex;
               matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
           } else {
               match = dictBase + matchIndex;
               matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
               if (matchIndex+matchLength >= dictLimit)
                   match = base + matchIndex;   /* preparation for next read of match[matchLength] */
           }
   
           DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ",
                       current, matchIndex, (U32)matchLength);
   
           if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
               break;   /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
           }
   
           if (match[matchLength] < ip[matchLength]) {  /* necessarily within buffer */
               /* match is smaller than current */
               *smallerPtr = matchIndex;             /* update smaller idx */
               commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
               if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
               DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u",
                           matchIndex, btLow, nextPtr[1]);
               smallerPtr = nextPtr+1;               /* new "candidate" => larger than match, which was smaller than target */
               matchIndex = nextPtr[1];              /* new matchIndex, larger than previous and closer to current */
           } else {
               /* match is larger than current */
               *largerPtr = matchIndex;
               commonLengthLarger = matchLength;
               if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
               DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u",
                           matchIndex, btLow, nextPtr[0]);
               largerPtr = nextPtr;
               matchIndex = nextPtr[0];
       }   }
   
       *smallerPtr = *largerPtr = 0;
   }
   
   
   static size_t
   ZSTD_DUBT_findBetterDictMatch (
           ZSTD_matchState_t* ms,
           const BYTE* const ip, const BYTE* const iend,
           size_t* offsetPtr,
           size_t bestLength,
           U32 nbCompares,
           U32 const mls,
           const ZSTD_dictMode_e dictMode)
   {
       const ZSTD_matchState_t * const dms = ms->dictMatchState;
       const ZSTD_compressionParameters* const dmsCParams = &dms->cParams;
       const U32 * const dictHashTable = dms->hashTable;
       U32         const hashLog = dmsCParams->hashLog;
       size_t      const h  = ZSTD_hashPtr(ip, hashLog, mls);
       U32               dictMatchIndex = dictHashTable[h];
   
       const BYTE* const base = ms->window.base;
       const BYTE* const prefixStart = base + ms->window.dictLimit;
       U32         const current = (U32)(ip-base);
       const BYTE* const dictBase = dms->window.base;
       const BYTE* const dictEnd = dms->window.nextSrc;
       U32         const dictHighLimit = (U32)(dms->window.nextSrc - dms->window.base);
       U32         const dictLowLimit = dms->window.lowLimit;
       U32         const dictIndexDelta = ms->window.lowLimit - dictHighLimit;
   
       U32*        const dictBt = dms->chainTable;
       U32         const btLog  = dmsCParams->chainLog - 1;
       U32         const btMask = (1 << btLog) - 1;
       U32         const btLow = (btMask >= dictHighLimit - dictLowLimit) ? dictLowLimit : dictHighLimit - btMask;
   
       size_t commonLengthSmaller=0, commonLengthLarger=0;
   
       (void)dictMode;
       assert(dictMode == ZSTD_dictMatchState);
   
       while (nbCompares-- && (dictMatchIndex > dictLowLimit)) {
           U32* const nextPtr = dictBt + 2*(dictMatchIndex & btMask);
           size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
           const BYTE* match = dictBase + dictMatchIndex;
           matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
           if (dictMatchIndex+matchLength >= dictHighLimit)
               match = base + dictMatchIndex + dictIndexDelta;   /* to prepare for next usage of match[matchLength] */
   
           if (matchLength > bestLength) {
               U32 matchIndex = dictMatchIndex + dictIndexDelta;
               if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) {
                   DEBUGLOG(9, "ZSTD_DUBT_findBetterDictMatch(%u) : found better match length %u -> %u and offsetCode %u -> %u (dictMatchIndex %u, matchIndex %u)",
                       current, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, ZSTD_REP_MOVE + current - matchIndex, dictMatchIndex, matchIndex);
                   bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
               }
               if (ip+matchLength == iend) {   /* reached end of input : ip[matchLength] is not valid, no way to know if it's larger or smaller than match */
                   break;   /* drop, to guarantee consistency (miss a little bit of compression) */
               }
           }
   
           if (match[matchLength] < ip[matchLength]) {
               if (dictMatchIndex <= btLow) { break; }   /* beyond tree size, stop the search */
               commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
               dictMatchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
           } else {
               /* match is larger than current */
               if (dictMatchIndex <= btLow) { break; }   /* beyond tree size, stop the search */
               commonLengthLarger = matchLength;
               dictMatchIndex = nextPtr[0];
           }
       }
   
       if (bestLength >= MINMATCH) {
           U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex;
           DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
                       current, (U32)bestLength, (U32)*offsetPtr, mIndex);
       }
       return bestLength;
   
   }
   
   
   static size_t
   ZSTD_DUBT_findBestMatch(ZSTD_matchState_t* ms,
                           const BYTE* const ip, const BYTE* const iend,
                           size_t* offsetPtr,
                           U32 const mls,
                           const ZSTD_dictMode_e dictMode)
   {
       const ZSTD_compressionParameters* const cParams = &ms->cParams;
       U32*   const hashTable = ms->hashTable;
       U32    const hashLog = cParams->hashLog;
       size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
       U32          matchIndex  = hashTable[h];
   
       const BYTE* const base = ms->window.base;
       U32    const current = (U32)(ip-base);
       U32    const windowLow = ZSTD_getLowestMatchIndex(ms, current, cParams->windowLog);
   
       U32*   const bt = ms->chainTable;
       U32    const btLog  = cParams->chainLog - 1;
       U32    const btMask = (1 << btLog) - 1;
       U32    const btLow = (btMask >= current) ? 0 : current - btMask;
       U32    const unsortLimit = MAX(btLow, windowLow);
   
       U32*         nextCandidate = bt + 2*(matchIndex&btMask);
       U32*         unsortedMark = bt + 2*(matchIndex&btMask) + 1;
       U32          nbCompares = 1U << cParams->searchLog;
       U32          nbCandidates = nbCompares;
       U32          previousCandidate = 0;
   
       DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", current);
       assert(ip <= iend-8);   /* required for h calculation */
   
       /* reach end of unsorted candidates list */
       while ( (matchIndex > unsortLimit)
            && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK)
            && (nbCandidates > 1) ) {
           DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted",
                       matchIndex);
           *unsortedMark = previousCandidate;  /* the unsortedMark becomes a reversed chain, to move up back to original position */
           previousCandidate = matchIndex;
           matchIndex = *nextCandidate;
           nextCandidate = bt + 2*(matchIndex&btMask);
           unsortedMark = bt + 2*(matchIndex&btMask) + 1;
           nbCandidates --;
       }
   
       /* nullify last candidate if it's still unsorted
        * simplification, detrimental to compression ratio, beneficial for speed */
       if ( (matchIndex > unsortLimit)
         && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) {
           DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u",
                       matchIndex);
           *nextCandidate = *unsortedMark = 0;
       }
   
       /* batch sort stacked candidates */
       matchIndex = previousCandidate;
       while (matchIndex) {  /* will end on matchIndex == 0 */
           U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1;
           U32 const nextCandidateIdx = *nextCandidateIdxPtr;
           ZSTD_insertDUBT1(ms, matchIndex, iend,
                            nbCandidates, unsortLimit, dictMode);
           matchIndex = nextCandidateIdx;
           nbCandidates++;
       }
   
       /* find longest match */
       {   size_t commonLengthSmaller = 0, commonLengthLarger = 0;
           const BYTE* const dictBase = ms->window.dictBase;
           const U32 dictLimit = ms->window.dictLimit;
           const BYTE* const dictEnd = dictBase + dictLimit;
           const BYTE* const prefixStart = base + dictLimit;
           U32* smallerPtr = bt + 2*(current&btMask);
           U32* largerPtr  = bt + 2*(current&btMask) + 1;
           U32 matchEndIdx = current + 8 + 1;
           U32 dummy32;   /* to be nullified at the end */
           size_t bestLength = 0;
   
           matchIndex  = hashTable[h];
           hashTable[h] = current;   /* Update Hash Table */
   
           while (nbCompares-- && (matchIndex > windowLow)) {
               U32* const nextPtr = bt + 2*(matchIndex & btMask);
               size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
               const BYTE* match;
   
               if ((dictMode != ZSTD_extDict) || (matchIndex+matchLength >= dictLimit)) {
                   match = base + matchIndex;
                   matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
               } else {
                   match = dictBase + matchIndex;
                   matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
                   if (matchIndex+matchLength >= dictLimit)
                       match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
               }
   
               if (matchLength > bestLength) {
                   if (matchLength > matchEndIdx - matchIndex)
                       matchEndIdx = matchIndex + (U32)matchLength;
                   if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
                       bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + current - matchIndex;
                   if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
                       if (dictMode == ZSTD_dictMatchState) {
                           nbCompares = 0; /* in addition to avoiding checking any
                                            * further in this loop, make sure we
                                            * skip checking in the dictionary. */
                       }
                       break;   /* drop, to guarantee consistency (miss a little bit of compression) */
                   }
               }
   
               if (match[matchLength] < ip[matchLength]) {
                   /* match is smaller than current */
                   *smallerPtr = matchIndex;             /* update smaller idx */
                   commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
                   if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
                   smallerPtr = nextPtr+1;               /* new "smaller" => larger of match */
                   matchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
               } else {
                   /* match is larger than current */
                   *largerPtr = matchIndex;
                   commonLengthLarger = matchLength;
                   if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
                   largerPtr = nextPtr;
                   matchIndex = nextPtr[0];
           }   }
   
           *smallerPtr = *largerPtr = 0;
   
           if (dictMode == ZSTD_dictMatchState && nbCompares) {
               bestLength = ZSTD_DUBT_findBetterDictMatch(
                       ms, ip, iend,
                       offsetPtr, bestLength, nbCompares,
                       mls, dictMode);
           }
   
           assert(matchEndIdx > current+8); /* ensure nextToUpdate is increased */
           ms->nextToUpdate = matchEndIdx - 8;   /* skip repetitive patterns */
           if (bestLength >= MINMATCH) {
               U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex;
               DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
                           current, (U32)bestLength, (U32)*offsetPtr, mIndex);
           }
           return bestLength;
       }
   }
   
   
   /** ZSTD_BtFindBestMatch() : Tree updater, providing best match */
   FORCE_INLINE_TEMPLATE size_t
   ZSTD_BtFindBestMatch( ZSTD_matchState_t* ms,
                   const BYTE* const ip, const BYTE* const iLimit,
                         size_t* offsetPtr,
                   const U32 mls /* template */,
                   const ZSTD_dictMode_e dictMode)
   {
       DEBUGLOG(7, "ZSTD_BtFindBestMatch");
       if (ip < ms->window.base + ms->nextToUpdate) return 0;   /* skipped area */
       ZSTD_updateDUBT(ms, ip, iLimit, mls);
       return ZSTD_DUBT_findBestMatch(ms, ip, iLimit, offsetPtr, mls, dictMode);
   }
   
   
   static size_t
   ZSTD_BtFindBestMatch_selectMLS (  ZSTD_matchState_t* ms,
                               const BYTE* ip, const BYTE* const iLimit,
                                     size_t* offsetPtr)
   {
       switch(ms->cParams.minMatch)
       {
       default : /* includes case 3 */
       case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict);
       case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict);
       case 7 :
       case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict);
       }
   }
   
   
   static size_t ZSTD_BtFindBestMatch_dictMatchState_selectMLS (
                           ZSTD_matchState_t* ms,
                           const BYTE* ip, const BYTE* const iLimit,
                           size_t* offsetPtr)
   {
       switch(ms->cParams.minMatch)
       {
       default : /* includes case 3 */
       case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState);
       case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState);
       case 7 :
       case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState);
       }
   }
   
   
   static size_t ZSTD_BtFindBestMatch_extDict_selectMLS (
                           ZSTD_matchState_t* ms,
                           const BYTE* ip, const BYTE* const iLimit,
                           size_t* offsetPtr)
   {
       switch(ms->cParams.minMatch)
       {
       default : /* includes case 3 */
       case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict);
       case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict);
       case 7 :
       case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict);
       }
   }
   
   
   
   /* *********************************
   *  Hash Chain
   ***********************************/
   #define NEXT_IN_CHAIN(d, mask)   chainTable[(d) & (mask)]
   
   /* Update chains up to ip (excluded)
      Assumption : always within prefix (i.e. not within extDict) */
   static U32 ZSTD_insertAndFindFirstIndex_internal(
                           ZSTD_matchState_t* ms,
                           const ZSTD_compressionParameters* const cParams,
                           const BYTE* ip, U32 const mls)
   {
       U32* const hashTable  = ms->hashTable;
       const U32 hashLog = cParams->hashLog;
       U32* const chainTable = ms->chainTable;
       const U32 chainMask = (1 << cParams->chainLog) - 1;
       const BYTE* const base = ms->window.base;
       const U32 target = (U32)(ip - base);
       U32 idx = ms->nextToUpdate;
   
       while(idx < target) { /* catch up */
           size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls);
           NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
           hashTable[h] = idx;
           idx++;
       }
   
       ms->nextToUpdate = target;
       return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
   }
   
   U32 ZSTD_insertAndFindFirstIndex(ZSTD_matchState_t* ms, const BYTE* ip) {
       const ZSTD_compressionParameters* const cParams = &ms->cParams;
       return ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, ms->cParams.minMatch);
   }
   
   
   /* inlining is important to hardwire a hot branch (template emulation) */
   FORCE_INLINE_TEMPLATE
   size_t ZSTD_HcFindBestMatch_generic (
                           ZSTD_matchState_t* ms,
                           const BYTE* const ip, const BYTE* const iLimit,
                           size_t* offsetPtr,
                           const U32 mls, const ZSTD_dictMode_e dictMode)
   {
       const ZSTD_compressionParameters* const cParams = &ms->cParams;
       U32* const chainTable = ms->chainTable;
       const U32 chainSize = (1 << cParams->chainLog);
       const U32 chainMask = chainSize-1;
       const BYTE* const base = ms->window.base;
       const BYTE* const dictBase = ms->window.dictBase;
       const U32 dictLimit = ms->window.dictLimit;
       const BYTE* const prefixStart = base + dictLimit;
       const BYTE* const dictEnd = dictBase + dictLimit;
       const U32 current = (U32)(ip-base);
       const U32 maxDistance = 1U << cParams->windowLog;
       const U32 lowestValid = ms->window.lowLimit;
       const U32 withinMaxDistance = (current - lowestValid > maxDistance) ? current - maxDistance : lowestValid;
       const U32 isDictionary = (ms->loadedDictEnd != 0);
       const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
       const U32 minChain = current > chainSize ? current - chainSize : 0;
       U32 nbAttempts = 1U << cParams->searchLog;
       size_t ml=4-1;
   
       /* HC4 match finder */
       U32 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls);
   
       for ( ; (matchIndex>lowLimit) & (nbAttempts>0) ; nbAttempts--) {
           size_t currentMl=0;
           if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
               const BYTE* const match = base + matchIndex;
               assert(matchIndex >= dictLimit);   /* ensures this is true if dictMode != ZSTD_extDict */
               if (match[ml] == ip[ml])   /* potentially better */
                   currentMl = ZSTD_count(ip, match, iLimit);
           } else {
               const BYTE* const match = dictBase + matchIndex;
               assert(match+4 <= dictEnd);
               if (MEM_read32(match) == MEM_read32(ip))   /* assumption : matchIndex <= dictLimit-4 (by table construction) */
                   currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4;
           }
   
           /* save best solution */
           if (currentMl > ml) {
               ml = currentMl;
               *offsetPtr = current - matchIndex + ZSTD_REP_MOVE;
               if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
           }
   
           if (matchIndex <= minChain) break;
           matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
       }
   
       if (dictMode == ZSTD_dictMatchState) {
           const ZSTD_matchState_t* const dms = ms->dictMatchState;
           const U32* const dmsChainTable = dms->chainTable;
           const U32 dmsChainSize         = (1 << dms->cParams.chainLog);
           const U32 dmsChainMask         = dmsChainSize - 1;
           const U32 dmsLowestIndex       = dms->window.dictLimit;
           const BYTE* const dmsBase      = dms->window.base;
           const BYTE* const dmsEnd       = dms->window.nextSrc;
           const U32 dmsSize              = (U32)(dmsEnd - dmsBase);
           const U32 dmsIndexDelta        = dictLimit - dmsSize;
           const U32 dmsMinChain = dmsSize > dmsChainSize ? dmsSize - dmsChainSize : 0;
   
           matchIndex = dms->hashTable[ZSTD_hashPtr(ip, dms->cParams.hashLog, mls)];
   
           for ( ; (matchIndex>dmsLowestIndex) & (nbAttempts>0) ; nbAttempts--) {
               size_t currentMl=0;
               const BYTE* const match = dmsBase + matchIndex;
               assert(match+4 <= dmsEnd);
               if (MEM_read32(match) == MEM_read32(ip))   /* assumption : matchIndex <= dictLimit-4 (by table construction) */
                   currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
   
               /* save best solution */
               if (currentMl > ml) {
                   ml = currentMl;
                   *offsetPtr = current - (matchIndex + dmsIndexDelta) + ZSTD_REP_MOVE;
                   if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
               }
   
               if (matchIndex <= dmsMinChain) break;
               matchIndex = dmsChainTable[matchIndex & dmsChainMask];
           }
       }
   
       return ml;
   }
   
   
   FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS (
                           ZSTD_matchState_t* ms,
                           const BYTE* ip, const BYTE* const iLimit,
                           size_t* offsetPtr)
   {
       switch(ms->cParams.minMatch)
       {
       default : /* includes case 3 */
       case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict);
       case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict);
       case 7 :
       case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict);
       }
   }
   
   
   static size_t ZSTD_HcFindBestMatch_dictMatchState_selectMLS (
                           ZSTD_matchState_t* ms,
                           const BYTE* ip, const BYTE* const iLimit,
                           size_t* offsetPtr)
   {
       switch(ms->cParams.minMatch)
       {
       default : /* includes case 3 */
       case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState);
       case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState);
       case 7 :
       case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState);
       }
   }
   
   
   FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS (
                           ZSTD_matchState_t* ms,
                           const BYTE* ip, const BYTE* const iLimit,
                           size_t* offsetPtr)
   {
       switch(ms->cParams.minMatch)
       {
       default : /* includes case 3 */
       case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict);
       case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict);
       case 7 :
       case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict);
       }
   }
   
   
   /* *******************************
   *  Common parser - lazy strategy
   *********************************/
   typedef enum { search_hashChain, search_binaryTree } searchMethod_e;
   
   FORCE_INLINE_TEMPLATE size_t
   ZSTD_compressBlock_lazy_generic(
                           ZSTD_matchState_t* ms, seqStore_t* seqStore,
                           U32 rep[ZSTD_REP_NUM],
                           const void* src, size_t srcSize,
                           const searchMethod_e searchMethod, const U32 depth,
                           ZSTD_dictMode_e const dictMode)
   {
       const BYTE* const istart = (const BYTE*)src;
       const BYTE* ip = istart;
       const BYTE* anchor = istart;
       const BYTE* const iend = istart + srcSize;
       const BYTE* const ilimit = iend - 8;
       const BYTE* const base = ms->window.base;
       const U32 prefixLowestIndex = ms->window.dictLimit;
       const BYTE* const prefixLowest = base + prefixLowestIndex;
   
       typedef size_t (*searchMax_f)(
                           ZSTD_matchState_t* ms,
                           const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr);
       searchMax_f const searchMax = dictMode == ZSTD_dictMatchState ?
           (searchMethod==search_binaryTree ? ZSTD_BtFindBestMatch_dictMatchState_selectMLS
                                            : ZSTD_HcFindBestMatch_dictMatchState_selectMLS) :
           (searchMethod==search_binaryTree ? ZSTD_BtFindBestMatch_selectMLS
                                            : ZSTD_HcFindBestMatch_selectMLS);
       U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0;
   
       const ZSTD_matchState_t* const dms = ms->dictMatchState;
       const U32 dictLowestIndex      = dictMode == ZSTD_dictMatchState ?
                                        dms->window.dictLimit : 0;
       const BYTE* const dictBase     = dictMode == ZSTD_dictMatchState ?
                                        dms->window.base : NULL;
       const BYTE* const dictLowest   = dictMode == ZSTD_dictMatchState ?
                                        dictBase + dictLowestIndex : NULL;
       const BYTE* const dictEnd      = dictMode == ZSTD_dictMatchState ?
                                        dms->window.nextSrc : NULL;
       const U32 dictIndexDelta       = dictMode == ZSTD_dictMatchState ?
                                        prefixLowestIndex - (U32)(dictEnd - dictBase) :
                                        0;
       const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest));
   
       DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u)", (U32)dictMode);
   
       /* init */
       ip += (dictAndPrefixLength == 0);
       if (dictMode == ZSTD_noDict) {
           U32 const current = (U32)(ip - base);
           U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, ms->cParams.windowLog);
           U32 const maxRep = current - windowLow;
           if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
           if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
       }
       if (dictMode == ZSTD_dictMatchState) {
           /* dictMatchState repCode checks don't currently handle repCode == 0
            * disabling. */
           assert(offset_1 <= dictAndPrefixLength);
           assert(offset_2 <= dictAndPrefixLength);
       }
   
       /* Match Loop */
   #if defined(__GNUC__) && defined(__x86_64__)
       /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
        * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
        */
       __asm__(".p2align 5");
   #endif
       while (ip < ilimit) {
           size_t matchLength=0;
           size_t offset=0;
           const BYTE* start=ip+1;
   
           /* check repCode */
           if (dictMode == ZSTD_dictMatchState) {
               const U32 repIndex = (U32)(ip - base) + 1 - offset_1;
               const BYTE* repMatch = (dictMode == ZSTD_dictMatchState
                                   && repIndex < prefixLowestIndex) ?
                                      dictBase + (repIndex - dictIndexDelta) :
                                      base + repIndex;
               if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
                   && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
                   const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
                   matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
                   if (depth==0) goto _storeSequence;
               }
           }
           if ( dictMode == ZSTD_noDict
             && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
               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 = 999999999;
               size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
               if (ml2 > matchLength)
                   matchLength = ml2, start = ip, offset=offsetFound;
           }
   
           if (matchLength < 4) {
               ip += ((ip-anchor) >> kSearchStrength) + 1;   /* jump faster over incompressible sections */
               continue;
           }
   
           /* let's try to find a better solution */
           if (depth>=1)
           while (ip<ilimit) {
               ip ++;
               if ( (dictMode == ZSTD_noDict)
                 && (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;
               }
               if (dictMode == ZSTD_dictMatchState) {
                   const U32 repIndex = (U32)(ip - base) - offset_1;
                   const BYTE* repMatch = repIndex < prefixLowestIndex ?
                                  dictBase + (repIndex - dictIndexDelta) :
                                  base + repIndex;
                   if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
                       && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
                       const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
                       size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 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=999999999;
                   size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                   int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                   int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
                   if ((ml2 >= 4) && (gain2 > gain1)) {
                       matchLength = ml2, offset = offset2, start = ip;
                       continue;   /* search a better one */
               }   }
   
               /* let's find an even better one */
               if ((depth==2) && (ip<ilimit)) {
                   ip ++;
                   if ( (dictMode == ZSTD_noDict)
                     && (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 * 4);
                       int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
                       if ((mlRep >= 4) && (gain2 > gain1))
                           matchLength = mlRep, offset = 0, start = ip;
                   }
                   if (dictMode == ZSTD_dictMatchState) {
                       const U32 repIndex = (U32)(ip - base) - offset_1;
                       const BYTE* repMatch = repIndex < prefixLowestIndex ?
                                      dictBase + (repIndex - dictIndexDelta) :
                                      base + repIndex;
                       if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
                           && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
                           const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
                           size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
                           int const gain2 = (int)(mlRep * 4);
                           int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
                           if ((mlRep >= 4) && (gain2 > gain1))
                               matchLength = mlRep, offset = 0, start = ip;
                       }
                   }
                   {   size_t offset2=999999999;
                       size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                       int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                       int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
                       if ((ml2 >= 4) && (gain2 > gain1)) {
                           matchLength = ml2, offset = offset2, start = ip;
                           continue;
               }   }   }
               break;  /* nothing found : store previous solution */
           }
   
           /* NOTE:
            * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior.
            * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which
            * overflows the pointer, which is undefined behavior.
            */
           /* catch up */
           if (offset) {
               if (dictMode == ZSTD_noDict) {
                   while ( ((start > anchor) & (start - (offset-ZSTD_REP_MOVE) > prefixLowest))
                        && (start[-1] == (start-(offset-ZSTD_REP_MOVE))[-1]) )  /* only search for offset within prefix */
                       { start--; matchLength++; }
               }
               if (dictMode == ZSTD_dictMatchState) {
                   U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
                   const BYTE* match = (matchIndex < prefixLowestIndex) ? dictBase + matchIndex - dictIndexDelta : base + matchIndex;
                   const BYTE* const mStart = (matchIndex < prefixLowestIndex) ? dictLowest : prefixLowest;
                   while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; }  /* catch up */
               }
               offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
           }
           /* store sequence */
   _storeSequence:
           {   size_t const litLength = start - anchor;
               ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offset, matchLength-MINMATCH);
               anchor = ip = start + matchLength;
           }
   
           /* check immediate repcode */
           if (dictMode == ZSTD_dictMatchState) {
               while (ip <= ilimit) {
                   U32 const current2 = (U32)(ip-base);
                   U32 const repIndex = current2 - offset_2;
                   const BYTE* repMatch = dictMode == ZSTD_dictMatchState
                       && repIndex < prefixLowestIndex ?
                           dictBase - dictIndexDelta + repIndex :
                           base + repIndex;
                   if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex) >= 3 /* intentional overflow */)
                      && (MEM_read32(repMatch) == MEM_read32(ip)) ) {
                       const BYTE* const repEnd2 = repIndex < prefixLowestIndex ? dictEnd : iend;
                       matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd2, prefixLowest) + 4;
                       offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset;   /* swap offset_2 <=> offset_1 */
                       ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH);
                       ip += matchLength;
                       anchor = ip;
                       continue;
                   }
                   break;
               }
           }
   
           if (dictMode == ZSTD_noDict) {
               while ( ((ip <= ilimit) & (offset_2>0))
                    && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) {
                   /* store sequence */
                   matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
                   offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap repcodes */
                   ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH);
                   ip += matchLength;
                   anchor = ip;
                   continue;   /* faster when present ... (?) */
       }   }   }
   
       /* Save reps for next block */
       rep[0] = offset_1 ? offset_1 : savedOffset;
       rep[1] = offset_2 ? offset_2 : savedOffset;
   
       /* Return the last literals size */
       return (size_t)(iend - anchor);
   }
   
   
   size_t ZSTD_compressBlock_btlazy2(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_noDict);
   }
   
   size_t ZSTD_compressBlock_lazy2(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_noDict);
   }
   
   size_t ZSTD_compressBlock_lazy(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_noDict);
   }
   
   size_t ZSTD_compressBlock_greedy(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_noDict);
   }
   
   size_t ZSTD_compressBlock_btlazy2_dictMatchState(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_dictMatchState);
   }
   
   size_t ZSTD_compressBlock_lazy2_dictMatchState(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dictMatchState);
   }
   
   size_t ZSTD_compressBlock_lazy_dictMatchState(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dictMatchState);
   }
   
   size_t ZSTD_compressBlock_greedy_dictMatchState(
           ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
           void const* src, size_t srcSize)
   {
       return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dictMatchState);
   }
   
   
   FORCE_INLINE_TEMPLATE
   size_t ZSTD_compressBlock_lazy_extDict_generic(
                           ZSTD_matchState_t* ms, seqStore_t* seqStore,
                           U32 rep[ZSTD_REP_NUM],
                           const void* src, size_t srcSize,
                           const searchMethod_e searchMethod, const U32 depth)
   {
       const BYTE* const istart = (const BYTE*)src;
       const BYTE* ip = istart;
       const BYTE* anchor = istart;
       const BYTE* const iend = istart + srcSize;
       const BYTE* const ilimit = iend - 8;
       const BYTE* const base = ms->window.base;
       const U32 dictLimit = ms->window.dictLimit;
       const BYTE* const prefixStart = base + dictLimit;
       const BYTE* const dictBase = ms->window.dictBase;
       const BYTE* const dictEnd  = dictBase + dictLimit;
       const BYTE* const dictStart  = dictBase + ms->window.lowLimit;
       const U32 windowLog = ms->cParams.windowLog;
   
       typedef size_t (*searchMax_f)(
                           ZSTD_matchState_t* ms,
                           const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr);
       searchMax_f searchMax = searchMethod==search_binaryTree ? ZSTD_BtFindBestMatch_extDict_selectMLS : ZSTD_HcFindBestMatch_extDict_selectMLS;
   
       U32 offset_1 = rep[0], offset_2 = rep[1];
   
       DEBUGLOG(5, "ZSTD_compressBlock_lazy_extDict_generic");
   
       /* init */
       ip += (ip == prefixStart);
   
       /* Match Loop */
   #if defined(__GNUC__) && defined(__x86_64__)
       /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the
        * code alignment is perturbed. To fix the instability align the loop on 32-bytes.
        */
       __asm__(".p2align 5");
   #endif
       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 windowLow = ZSTD_getLowestMatchIndex(ms, current+1, windowLog);
               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 > windowLow))   /* 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 = 999999999;
               size_t const ml2 = searchMax(ms, ip, iend, &offsetFound);
               if (ml2 > matchLength)
                   matchLength = ml2, start = ip, offset=offsetFound;
           }
   
            if (matchLength < 4) {
               ip += ((ip-anchor) >> kSearchStrength) + 1;   /* jump faster over incompressible sections */
               continue;
           }
   
           /* let's try to find a better solution */
           if (depth>=1)
          while (ip<ilimit) {
              ip ++;
              current++;
              /* check repCode */
              if (offset) {
                  const U32 windowLow = ZSTD_getLowestMatchIndex(ms, current, windowLog);
                  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 > windowLow))  /* 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=999999999;
                  size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                  int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                  int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4);
                  if ((ml2 >= 4) && (gain2 > gain1)) {
                      matchLength = ml2, offset = offset2, start = ip;
                      continue;   /* search a better one */
              }   }
  
              /* let's find an even better one */
              if ((depth==2) && (ip<ilimit)) {
                  ip ++;
                  current++;
                  /* check repCode */
                  if (offset) {
                      const U32 windowLow = ZSTD_getLowestMatchIndex(ms, current, windowLog);
                      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 > windowLow))  /* 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=999999999;
                      size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                      int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1));   /* raw approx */
                      int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7);
                      if ((ml2 >= 4) && (gain2 > gain1)) {
                          matchLength = ml2, offset = offset2, start = ip;
                          continue;
              }   }   }
              break;  /* nothing found : store previous solution */
          }
  
          /* catch up */
          if (offset) {
              U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE));
              const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
              const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
              while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; }  /* catch up */
              offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE);
          }
  
          /* store sequence */
  _storeSequence:
          {   size_t const litLength = start - anchor;
              ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offset, matchLength-MINMATCH);
              anchor = ip = start + matchLength;
          }
  
          /* check immediate repcode */
          while (ip <= ilimit) {
              const U32 repCurrent = (U32)(ip-base);
              const U32 windowLow = ZSTD_getLowestMatchIndex(ms, repCurrent, windowLog);
              const U32 repIndex = repCurrent - offset_2;
              const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
              const BYTE* const repMatch = repBase + repIndex;
              if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow))  /* intentional overflow */
              if (MEM_read32(ip) == MEM_read32(repMatch)) {
                  /* repcode detected we should take it */
                  const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
                  matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
                  offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset;   /* swap offset history */
                  ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH);
                  ip += matchLength;
                  anchor = ip;
                  continue;   /* faster when present ... (?) */
              }
              break;
      }   }
  
      /* Save reps for next block */
      rep[0] = offset_1;
      rep[1] = offset_2;
  
      /* Return the last literals size */
      return (size_t)(iend - anchor);
  }
  
  
  size_t ZSTD_compressBlock_greedy_extDict(
          ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
          void const* src, size_t srcSize)
  {
      return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0);
  }
  
  size_t ZSTD_compressBlock_lazy_extDict(
          ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
          void const* src, size_t srcSize)
  
  {
      return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1);
  }
  
  size_t ZSTD_compressBlock_lazy2_extDict(
          ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
          void const* src, size_t srcSize)
  
  {
      return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2);
  }
  
  size_t ZSTD_compressBlock_btlazy2_extDict(
          ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
          void const* src, size_t srcSize)
  
  {
      return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2);
  }

Cache object: 66120458032066da000488bddf1961a5