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

     /*
      * Copyright (c) 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 : curr >= btlow == (curr - btmask)
     *  doesn't fail */
    static void
    ZSTD_insertDUBT1(const ZSTD_matchState_t* ms,
                     U32 curr, 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 = (curr>=dictLimit) ? base + curr : dictBase + curr;
        const BYTE* const iend = (curr>=dictLimit) ? inputEnd : dictBase + dictLimit;
        const BYTE* const dictEnd = dictBase + dictLimit;
        const BYTE* const prefixStart = base + dictLimit;
        const BYTE* match;
        U32* smallerPtr = bt + 2*(curr&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 = (curr - windowValid > maxDistance) ? curr - maxDistance : windowValid;
    
    
        DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)",
                    curr, dictLimit, windowLow);
        assert(curr >= btLow);
        assert(ip < iend);   /* condition for ZSTD_count */
    
        for (; nbCompares && (matchIndex > windowLow); --nbCompares) {
            U32* const nextPtr = bt + 2*(matchIndex & btMask);
            size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
            assert(matchIndex < curr);
           /* 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*/
             || (curr < 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 */
                    || (curr < 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 ",
                       curr, 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 (
           const 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 curr = (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);
   
       for (; nbCompares && (dictMatchIndex > dictLowLimit); --nbCompares) {
           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(curr-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)",
                       curr, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, STORE_OFFSET(curr - matchIndex), dictMatchIndex, matchIndex);
                   bestLength = matchLength, *offsetPtr = STORE_OFFSET(curr - 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 = curr - (U32)STORED_OFFSET(*offsetPtr); (void)mIndex;
           DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
                       curr, (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 curr = (U32)(ip-base);
       U32    const windowLow = ZSTD_getLowestMatchIndex(ms, curr, cParams->windowLog);
   
       U32*   const bt = ms->chainTable;
       U32    const btLog  = cParams->chainLog - 1;
       U32    const btMask = (1 << btLog) - 1;
       U32    const btLow = (btMask >= curr) ? 0 : curr - 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) ", curr);
       assert(ip <= iend-8);   /* required for h calculation */
       assert(dictMode != ZSTD_dedicatedDictSearch);
   
       /* 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*(curr&btMask);
           U32* largerPtr  = bt + 2*(curr&btMask) + 1;
           U32 matchEndIdx = curr + 8 + 1;
           U32 dummy32;   /* to be nullified at the end */
           size_t bestLength = 0;
   
           matchIndex  = hashTable[h];
           hashTable[h] = curr;   /* Update Hash Table */
   
           for (; nbCompares && (matchIndex > windowLow); --nbCompares) {
               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(curr-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
                       bestLength = matchLength, *offsetPtr = STORE_OFFSET(curr - 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;
   
           assert(nbCompares <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
           if (dictMode == ZSTD_dictMatchState && nbCompares) {
               bestLength = ZSTD_DUBT_findBetterDictMatch(
                       ms, ip, iend,
                       offsetPtr, bestLength, nbCompares,
                       mls, dictMode);
           }
   
           assert(matchEndIdx > curr+8); /* ensure nextToUpdate is increased */
           ms->nextToUpdate = matchEndIdx - 8;   /* skip repetitive patterns */
           if (bestLength >= MINMATCH) {
               U32 const mIndex = curr - (U32)STORED_OFFSET(*offsetPtr); (void)mIndex;
               DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
                           curr, (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);
   }
   
   /***********************************
   * Dedicated dict search
   ***********************************/
   
   void ZSTD_dedicatedDictSearch_lazy_loadDictionary(ZSTD_matchState_t* ms, const BYTE* const ip)
   {
       const BYTE* const base = ms->window.base;
       U32 const target = (U32)(ip - base);
       U32* const hashTable = ms->hashTable;
       U32* const chainTable = ms->chainTable;
       U32 const chainSize = 1 << ms->cParams.chainLog;
       U32 idx = ms->nextToUpdate;
       U32 const minChain = chainSize < target - idx ? target - chainSize : idx;
       U32 const bucketSize = 1 << ZSTD_LAZY_DDSS_BUCKET_LOG;
       U32 const cacheSize = bucketSize - 1;
       U32 const chainAttempts = (1 << ms->cParams.searchLog) - cacheSize;
       U32 const chainLimit = chainAttempts > 255 ? 255 : chainAttempts;
   
       /* We know the hashtable is oversized by a factor of `bucketSize`.
        * We are going to temporarily pretend `bucketSize == 1`, keeping only a
        * single entry. We will use the rest of the space to construct a temporary
        * chaintable.
        */
       U32 const hashLog = ms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG;
       U32* const tmpHashTable = hashTable;
       U32* const tmpChainTable = hashTable + ((size_t)1 << hashLog);
       U32 const tmpChainSize = (U32)((1 << ZSTD_LAZY_DDSS_BUCKET_LOG) - 1) << hashLog;
       U32 const tmpMinChain = tmpChainSize < target ? target - tmpChainSize : idx;
       U32 hashIdx;
   
       assert(ms->cParams.chainLog <= 24);
       assert(ms->cParams.hashLog > ms->cParams.chainLog);
       assert(idx != 0);
       assert(tmpMinChain <= minChain);
   
       /* fill conventional hash table and conventional chain table */
       for ( ; idx < target; idx++) {
           U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch);
           if (idx >= tmpMinChain) {
               tmpChainTable[idx - tmpMinChain] = hashTable[h];
           }
           tmpHashTable[h] = idx;
       }
   
       /* sort chains into ddss chain table */
       {
           U32 chainPos = 0;
           for (hashIdx = 0; hashIdx < (1U << hashLog); hashIdx++) {
               U32 count;
               U32 countBeyondMinChain = 0;
               U32 i = tmpHashTable[hashIdx];
               for (count = 0; i >= tmpMinChain && count < cacheSize; count++) {
                   /* skip through the chain to the first position that won't be
                    * in the hash cache bucket */
                   if (i < minChain) {
                       countBeyondMinChain++;
                   }
                   i = tmpChainTable[i - tmpMinChain];
               }
               if (count == cacheSize) {
                   for (count = 0; count < chainLimit;) {
                       if (i < minChain) {
                           if (!i || ++countBeyondMinChain > cacheSize) {
                               /* only allow pulling `cacheSize` number of entries
                                * into the cache or chainTable beyond `minChain`,
                                * to replace the entries pulled out of the
                                * chainTable into the cache. This lets us reach
                                * back further without increasing the total number
                                * of entries in the chainTable, guaranteeing the
                                * DDSS chain table will fit into the space
                                * allocated for the regular one. */
                               break;
                           }
                       }
                       chainTable[chainPos++] = i;
                       count++;
                       if (i < tmpMinChain) {
                           break;
                       }
                       i = tmpChainTable[i - tmpMinChain];
                   }
               } else {
                   count = 0;
               }
               if (count) {
                   tmpHashTable[hashIdx] = ((chainPos - count) << 8) + count;
               } else {
                   tmpHashTable[hashIdx] = 0;
               }
           }
           assert(chainPos <= chainSize); /* I believe this is guaranteed... */
       }
   
       /* move chain pointers into the last entry of each hash bucket */
       for (hashIdx = (1 << hashLog); hashIdx; ) {
           U32 const bucketIdx = --hashIdx << ZSTD_LAZY_DDSS_BUCKET_LOG;
           U32 const chainPackedPointer = tmpHashTable[hashIdx];
           U32 i;
           for (i = 0; i < cacheSize; i++) {
               hashTable[bucketIdx + i] = 0;
           }
           hashTable[bucketIdx + bucketSize - 1] = chainPackedPointer;
       }
   
       /* fill the buckets of the hash table */
       for (idx = ms->nextToUpdate; idx < target; idx++) {
           U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch)
                      << ZSTD_LAZY_DDSS_BUCKET_LOG;
           U32 i;
           /* Shift hash cache down 1. */
           for (i = cacheSize - 1; i; i--)
               hashTable[h + i] = hashTable[h + i - 1];
           hashTable[h] = idx;
       }
   
       ms->nextToUpdate = target;
   }
   
   /* Returns the longest match length found in the dedicated dict search structure.
    * If none are longer than the argument ml, then ml will be returned.
    */
   FORCE_INLINE_TEMPLATE
   size_t ZSTD_dedicatedDictSearch_lazy_search(size_t* offsetPtr, size_t ml, U32 nbAttempts,
                                               const ZSTD_matchState_t* const dms,
                                               const BYTE* const ip, const BYTE* const iLimit,
                                               const BYTE* const prefixStart, const U32 curr,
                                               const U32 dictLimit, const size_t ddsIdx) {
       const U32 ddsLowestIndex  = dms->window.dictLimit;
       const BYTE* const ddsBase = dms->window.base;
       const BYTE* const ddsEnd  = dms->window.nextSrc;
       const U32 ddsSize         = (U32)(ddsEnd - ddsBase);
       const U32 ddsIndexDelta   = dictLimit - ddsSize;
       const U32 bucketSize      = (1 << ZSTD_LAZY_DDSS_BUCKET_LOG);
       const U32 bucketLimit     = nbAttempts < bucketSize - 1 ? nbAttempts : bucketSize - 1;
       U32 ddsAttempt;
       U32 matchIndex;
   
       for (ddsAttempt = 0; ddsAttempt < bucketSize - 1; ddsAttempt++) {
           PREFETCH_L1(ddsBase + dms->hashTable[ddsIdx + ddsAttempt]);
       }
   
       {
           U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1];
           U32 const chainIndex = chainPackedPointer >> 8;
   
           PREFETCH_L1(&dms->chainTable[chainIndex]);
       }
   
       for (ddsAttempt = 0; ddsAttempt < bucketLimit; ddsAttempt++) {
           size_t currentMl=0;
           const BYTE* match;
           matchIndex = dms->hashTable[ddsIdx + ddsAttempt];
           match = ddsBase + matchIndex;
   
           if (!matchIndex) {
               return ml;
           }
   
           /* guaranteed by table construction */
           (void)ddsLowestIndex;
           assert(matchIndex >= ddsLowestIndex);
           assert(match+4 <= ddsEnd);
           if (MEM_read32(match) == MEM_read32(ip)) {
               /* assumption : matchIndex <= dictLimit-4 (by table construction) */
               currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4;
           }
   
           /* save best solution */
           if (currentMl > ml) {
               ml = currentMl;
               *offsetPtr = STORE_OFFSET(curr - (matchIndex + ddsIndexDelta));
               if (ip+currentMl == iLimit) {
                   /* best possible, avoids read overflow on next attempt */
                   return ml;
               }
           }
       }
   
       {
           U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1];
           U32 chainIndex = chainPackedPointer >> 8;
           U32 const chainLength = chainPackedPointer & 0xFF;
           U32 const chainAttempts = nbAttempts - ddsAttempt;
           U32 const chainLimit = chainAttempts > chainLength ? chainLength : chainAttempts;
           U32 chainAttempt;
   
           for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++) {
               PREFETCH_L1(ddsBase + dms->chainTable[chainIndex + chainAttempt]);
           }
   
           for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++, chainIndex++) {
               size_t currentMl=0;
               const BYTE* match;
               matchIndex = dms->chainTable[chainIndex];
               match = ddsBase + matchIndex;
   
               /* guaranteed by table construction */
               assert(matchIndex >= ddsLowestIndex);
               assert(match+4 <= ddsEnd);
               if (MEM_read32(match) == MEM_read32(ip)) {
                   /* assumption : matchIndex <= dictLimit-4 (by table construction) */
                   currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4;
               }
   
               /* save best solution */
               if (currentMl > ml) {
                   ml = currentMl;
                   *offsetPtr = STORE_OFFSET(curr - (matchIndex + ddsIndexDelta));
                   if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
               }
           }
       }
       return ml;
   }
   
   
   /* *********************************
   *  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) */
   FORCE_INLINE_TEMPLATE 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(
                           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 curr = (U32)(ip-base);
       const U32 maxDistance = 1U << cParams->windowLog;
       const U32 lowestValid = ms->window.lowLimit;
       const U32 withinMaxDistance = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
       const U32 isDictionary = (ms->loadedDictEnd != 0);
       const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
       const U32 minChain = curr > chainSize ? curr - chainSize : 0;
       U32 nbAttempts = 1U << cParams->searchLog;
       size_t ml=4-1;
   
       const ZSTD_matchState_t* const dms = ms->dictMatchState;
       const U32 ddsHashLog = dictMode == ZSTD_dedicatedDictSearch
                            ? dms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG : 0;
       const size_t ddsIdx = dictMode == ZSTD_dedicatedDictSearch
                           ? ZSTD_hashPtr(ip, ddsHashLog, mls) << ZSTD_LAZY_DDSS_BUCKET_LOG : 0;
   
       U32 matchIndex;
   
       if (dictMode == ZSTD_dedicatedDictSearch) {
           const U32* entry = &dms->hashTable[ddsIdx];
           PREFETCH_L1(entry);
       }
   
       /* HC4 match finder */
       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 = STORE_OFFSET(curr - matchIndex);
               if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
           }
   
           if (matchIndex <= minChain) break;
           matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
       }
   
       assert(nbAttempts <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
       if (dictMode == ZSTD_dedicatedDictSearch) {
           ml = ZSTD_dedicatedDictSearch_lazy_search(offsetPtr, ml, nbAttempts, dms,
                                                     ip, iLimit, prefixStart, curr, dictLimit, ddsIdx);
       } else if (dictMode == ZSTD_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;
                   assert(curr > matchIndex + dmsIndexDelta);
                   *offsetPtr = STORE_OFFSET(curr - (matchIndex + dmsIndexDelta));
                   if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
               }
   
               if (matchIndex <= dmsMinChain) break;
   
               matchIndex = dmsChainTable[matchIndex & dmsChainMask];
           }
       }
   
       return ml;
   }
   
   /* *********************************
   * (SIMD) Row-based matchfinder
   ***********************************/
   /* Constants for row-based hash */
   #define ZSTD_ROW_HASH_TAG_OFFSET 16     /* byte offset of hashes in the match state's tagTable from the beginning of a row */
   #define ZSTD_ROW_HASH_TAG_BITS 8        /* nb bits to use for the tag */
   #define ZSTD_ROW_HASH_TAG_MASK ((1u << ZSTD_ROW_HASH_TAG_BITS) - 1)
   #define ZSTD_ROW_HASH_MAX_ENTRIES 64    /* absolute maximum number of entries per row, for all configurations */
   
   #define ZSTD_ROW_HASH_CACHE_MASK (ZSTD_ROW_HASH_CACHE_SIZE - 1)
   
   typedef U64 ZSTD_VecMask;   /* Clarifies when we are interacting with a U64 representing a mask of matches */
   
   /* ZSTD_VecMask_next():
    * Starting from the LSB, returns the idx of the next non-zero bit.
    * Basically counting the nb of trailing zeroes.
    */
   static U32 ZSTD_VecMask_next(ZSTD_VecMask val) {
       assert(val != 0);
   #   if defined(_MSC_VER) && defined(_WIN64)
           if (val != 0) {
               unsigned long r;
               _BitScanForward64(&r, val);
               return (U32)(r);
           } else {
               /* Should not reach this code path */
               __assume(0);
           }
   #   elif (defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4))))
       if (sizeof(size_t) == 4) {
           U32 mostSignificantWord = (U32)(val >> 32);
           U32 leastSignificantWord = (U32)val;
           if (leastSignificantWord == 0) {
               return 32 + (U32)__builtin_ctz(mostSignificantWord);
           } else {
               return (U32)__builtin_ctz(leastSignificantWord);
           }
       } else {
           return (U32)__builtin_ctzll(val);
       }
   #   else
       /* Software ctz version: http://aggregate.org/MAGIC/#Trailing%20Zero%20Count
        * and: https://stackoverflow.com/questions/2709430/count-number-of-bits-in-a-64-bit-long-big-integer
        */
       val = ~val & (val - 1ULL); /* Lowest set bit mask */
       val = val - ((val >> 1) & 0x5555555555555555);
       val = (val & 0x3333333333333333ULL) + ((val >> 2) & 0x3333333333333333ULL);
       return (U32)((((val + (val >> 4)) & 0xF0F0F0F0F0F0F0FULL) * 0x101010101010101ULL) >> 56);
   #   endif
   }
   
   /* ZSTD_rotateRight_*():
    * Rotates a bitfield to the right by "count" bits.
    * https://en.wikipedia.org/w/index.php?title=Circular_shift&oldid=991635599#Implementing_circular_shifts
    */
   FORCE_INLINE_TEMPLATE
   U64 ZSTD_rotateRight_U64(U64 const value, U32 count) {
       assert(count < 64);
       count &= 0x3F; /* for fickle pattern recognition */
       return (value >> count) | (U64)(value << ((0U - count) & 0x3F));
   }
   
   FORCE_INLINE_TEMPLATE
   U32 ZSTD_rotateRight_U32(U32 const value, U32 count) {
       assert(count < 32);
       count &= 0x1F; /* for fickle pattern recognition */
       return (value >> count) | (U32)(value << ((0U - count) & 0x1F));
   }
   
   FORCE_INLINE_TEMPLATE
   U16 ZSTD_rotateRight_U16(U16 const value, U32 count) {
       assert(count < 16);
       count &= 0x0F; /* for fickle pattern recognition */
       return (value >> count) | (U16)(value << ((0U - count) & 0x0F));
   }
   
   /* ZSTD_row_nextIndex():
    * Returns the next index to insert at within a tagTable row, and updates the "head"
    * value to reflect the update. Essentially cycles backwards from [0, {entries per row})
    */
   FORCE_INLINE_TEMPLATE U32 ZSTD_row_nextIndex(BYTE* const tagRow, U32 const rowMask) {
     U32 const next = (*tagRow - 1) & rowMask;
     *tagRow = (BYTE)next;
     return next;
   }
   
   /* ZSTD_isAligned():
    * Checks that a pointer is aligned to "align" bytes which must be a power of 2.
    */
   MEM_STATIC int ZSTD_isAligned(void const* ptr, size_t align) {
       assert((align & (align - 1)) == 0);
       return (((size_t)ptr) & (align - 1)) == 0;
   }
   
   /* ZSTD_row_prefetch():
    * Performs prefetching for the hashTable and tagTable at a given row.
    */
   FORCE_INLINE_TEMPLATE void ZSTD_row_prefetch(U32 const* hashTable, U16 const* tagTable, U32 const relRow, U32 const rowLog) {
       PREFETCH_L1(hashTable + relRow);
       if (rowLog >= 5) {
           PREFETCH_L1(hashTable + relRow + 16);
           /* Note: prefetching more of the hash table does not appear to be beneficial for 128-entry rows */
       }
       PREFETCH_L1(tagTable + relRow);
       if (rowLog == 6) {
           PREFETCH_L1(tagTable + relRow + 32);
       }
       assert(rowLog == 4 || rowLog == 5 || rowLog == 6);
       assert(ZSTD_isAligned(hashTable + relRow, 64));                 /* prefetched hash row always 64-byte aligned */
       assert(ZSTD_isAligned(tagTable + relRow, (size_t)1 << rowLog)); /* prefetched tagRow sits on correct multiple of bytes (32,64,128) */
   }
   
   /* ZSTD_row_fillHashCache():
    * Fill up the hash cache starting at idx, prefetching up to ZSTD_ROW_HASH_CACHE_SIZE entries,
    * but not beyond iLimit.
    */
   FORCE_INLINE_TEMPLATE void ZSTD_row_fillHashCache(ZSTD_matchState_t* ms, const BYTE* base,
                                      U32 const rowLog, U32 const mls,
                                      U32 idx, const BYTE* const iLimit)
   {
       U32 const* const hashTable = ms->hashTable;
       U16 const* const tagTable = ms->tagTable;
       U32 const hashLog = ms->rowHashLog;
       U32 const maxElemsToPrefetch = (base + idx) > iLimit ? 0 : (U32)(iLimit - (base + idx) + 1);
       U32 const lim = idx + MIN(ZSTD_ROW_HASH_CACHE_SIZE, maxElemsToPrefetch);
   
       for (; idx < lim; ++idx) {
           U32 const hash = (U32)ZSTD_hashPtr(base + idx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
           U32 const row = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
           ZSTD_row_prefetch(hashTable, tagTable, row, rowLog);
           ms->hashCache[idx & ZSTD_ROW_HASH_CACHE_MASK] = hash;
       }
   
       DEBUGLOG(6, "ZSTD_row_fillHashCache(): [%u %u %u %u %u %u %u %u]", ms->hashCache[0], ms->hashCache[1],
                                                        ms->hashCache[2], ms->hashCache[3], ms->hashCache[4],
                                                        ms->hashCache[5], ms->hashCache[6], ms->hashCache[7]);
   }
   
   /* ZSTD_row_nextCachedHash():
    * Returns the hash of base + idx, and replaces the hash in the hash cache with the byte at
    * base + idx + ZSTD_ROW_HASH_CACHE_SIZE. Also prefetches the appropriate rows from hashTable and tagTable.
    */
   FORCE_INLINE_TEMPLATE U32 ZSTD_row_nextCachedHash(U32* cache, U32 const* hashTable,
                                                     U16 const* tagTable, BYTE const* base,
                                                     U32 idx, U32 const hashLog,
                                                     U32 const rowLog, U32 const mls)
   {
       U32 const newHash = (U32)ZSTD_hashPtr(base+idx+ZSTD_ROW_HASH_CACHE_SIZE, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
       U32 const row = (newHash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
       ZSTD_row_prefetch(hashTable, tagTable, row, rowLog);
       {   U32 const hash = cache[idx & ZSTD_ROW_HASH_CACHE_MASK];
           cache[idx & ZSTD_ROW_HASH_CACHE_MASK] = newHash;
           return hash;
       }
   }
   
   /* ZSTD_row_update_internalImpl():
    * Updates the hash table with positions starting from updateStartIdx until updateEndIdx.
    */
   FORCE_INLINE_TEMPLATE void ZSTD_row_update_internalImpl(ZSTD_matchState_t* ms,
                                                           U32 updateStartIdx, U32 const updateEndIdx,
                                                           U32 const mls, U32 const rowLog,
                                                           U32 const rowMask, U32 const useCache)
   {
       U32* const hashTable = ms->hashTable;
       U16* const tagTable = ms->tagTable;
       U32 const hashLog = ms->rowHashLog;
       const BYTE* const base = ms->window.base;
   
       DEBUGLOG(6, "ZSTD_row_update_internalImpl(): updateStartIdx=%u, updateEndIdx=%u", updateStartIdx, updateEndIdx);
       for (; updateStartIdx < updateEndIdx; ++updateStartIdx) {
           U32 const hash = useCache ? ZSTD_row_nextCachedHash(ms->hashCache, hashTable, tagTable, base, updateStartIdx, hashLog, rowLog, mls)
                                     : (U32)ZSTD_hashPtr(base + updateStartIdx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
           U32 const relRow = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
           U32* const row = hashTable + relRow;
           BYTE* tagRow = (BYTE*)(tagTable + relRow);  /* Though tagTable is laid out as a table of U16, each tag is only 1 byte.
                                                          Explicit cast allows us to get exact desired position within each row */
           U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask);
   
           assert(hash == ZSTD_hashPtr(base + updateStartIdx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls));
           ((BYTE*)tagRow)[pos + ZSTD_ROW_HASH_TAG_OFFSET] = hash & ZSTD_ROW_HASH_TAG_MASK;
           row[pos] = updateStartIdx;
       }
   }
   
   /* ZSTD_row_update_internal():
    * Inserts the byte at ip into the appropriate position in the hash table, and updates ms->nextToUpdate.
    * Skips sections of long matches as is necessary.
    */
   FORCE_INLINE_TEMPLATE void ZSTD_row_update_internal(ZSTD_matchState_t* ms, const BYTE* ip,
                                                       U32 const mls, U32 const rowLog,
                                                       U32 const rowMask, U32 const useCache)
   {
       U32 idx = ms->nextToUpdate;
       const BYTE* const base = ms->window.base;
       const U32 target = (U32)(ip - base);
       const U32 kSkipThreshold = 384;
       const U32 kMaxMatchStartPositionsToUpdate = 96;
       const U32 kMaxMatchEndPositionsToUpdate = 32;
   
       if (useCache) {
           /* Only skip positions when using hash cache, i.e.
            * if we are loading a dict, don't skip anything.
            * If we decide to skip, then we only update a set number
            * of positions at the beginning and end of the match.
            */
           if (UNLIKELY(target - idx > kSkipThreshold)) {
               U32 const bound = idx + kMaxMatchStartPositionsToUpdate;
               ZSTD_row_update_internalImpl(ms, idx, bound, mls, rowLog, rowMask, useCache);
               idx = target - kMaxMatchEndPositionsToUpdate;
               ZSTD_row_fillHashCache(ms, base, rowLog, mls, idx, ip+1);
           }
       }
       assert(target >= idx);
       ZSTD_row_update_internalImpl(ms, idx, target, mls, rowLog, rowMask, useCache);
       ms->nextToUpdate = target;
   }
   
   /* ZSTD_row_update():
    * External wrapper for ZSTD_row_update_internal(). Used for filling the hashtable during dictionary
    * processing.
    */
   void ZSTD_row_update(ZSTD_matchState_t* const ms, const BYTE* ip) {
       const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6);
       const U32 rowMask = (1u << rowLog) - 1;
       const U32 mls = MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */);
   
       DEBUGLOG(5, "ZSTD_row_update(), rowLog=%u", rowLog);
       ZSTD_row_update_internal(ms, ip, mls, rowLog, rowMask, 0 /* dont use cache */);
   }
   
   #if defined(ZSTD_ARCH_X86_SSE2)
   FORCE_INLINE_TEMPLATE ZSTD_VecMask
   ZSTD_row_getSSEMask(int nbChunks, const BYTE* const src, const BYTE tag, const U32 head)
   {
       const __m128i comparisonMask = _mm_set1_epi8((char)tag);
       int matches[4] = {0};
       int i;
       assert(nbChunks == 1 || nbChunks == 2 || nbChunks == 4);
       for (i=0; i<nbChunks; i++) {
           const __m128i chunk = _mm_loadu_si128((const __m128i*)(const void*)(src + 16*i));
           const __m128i equalMask = _mm_cmpeq_epi8(chunk, comparisonMask);
           matches[i] = _mm_movemask_epi8(equalMask);
       }
       if (nbChunks == 1) return ZSTD_rotateRight_U16((U16)matches[0], head);
      if (nbChunks == 2) return ZSTD_rotateRight_U32((U32)matches[1] << 16 | (U32)matches[0], head);
      assert(nbChunks == 4);
      return ZSTD_rotateRight_U64((U64)matches[3] << 48 | (U64)matches[2] << 32 | (U64)matches[1] << 16 | (U64)matches[0], head);
  }
  #endif
  
  /* Returns a ZSTD_VecMask (U32) that has the nth bit set to 1 if the newly-computed "tag" matches
   * the hash at the nth position in a row of the tagTable.
   * Each row is a circular buffer beginning at the value of "head". So we must rotate the "matches" bitfield
   * to match up with the actual layout of the entries within the hashTable */
  FORCE_INLINE_TEMPLATE ZSTD_VecMask
  ZSTD_row_getMatchMask(const BYTE* const tagRow, const BYTE tag, const U32 head, const U32 rowEntries)
  {
      const BYTE* const src = tagRow + ZSTD_ROW_HASH_TAG_OFFSET;
      assert((rowEntries == 16) || (rowEntries == 32) || rowEntries == 64);
      assert(rowEntries <= ZSTD_ROW_HASH_MAX_ENTRIES);
  
  #if defined(ZSTD_ARCH_X86_SSE2)
  
      return ZSTD_row_getSSEMask(rowEntries / 16, src, tag, head);
  
  #else /* SW or NEON-LE */
  
  # if defined(ZSTD_ARCH_ARM_NEON)
    /* This NEON path only works for little endian - otherwise use SWAR below */
      if (MEM_isLittleEndian()) {
          if (rowEntries == 16) {
              const uint8x16_t chunk = vld1q_u8(src);
              const uint16x8_t equalMask = vreinterpretq_u16_u8(vceqq_u8(chunk, vdupq_n_u8(tag)));
              const uint16x8_t t0 = vshlq_n_u16(equalMask, 7);
              const uint32x4_t t1 = vreinterpretq_u32_u16(vsriq_n_u16(t0, t0, 14));
              const uint64x2_t t2 = vreinterpretq_u64_u32(vshrq_n_u32(t1, 14));
              const uint8x16_t t3 = vreinterpretq_u8_u64(vsraq_n_u64(t2, t2, 28));
              const U16 hi = (U16)vgetq_lane_u8(t3, 8);
              const U16 lo = (U16)vgetq_lane_u8(t3, 0);
              return ZSTD_rotateRight_U16((hi << 8) | lo, head);
          } else if (rowEntries == 32) {
              const uint16x8x2_t chunk = vld2q_u16((const U16*)(const void*)src);
              const uint8x16_t chunk0 = vreinterpretq_u8_u16(chunk.val[0]);
              const uint8x16_t chunk1 = vreinterpretq_u8_u16(chunk.val[1]);
              const uint8x16_t equalMask0 = vceqq_u8(chunk0, vdupq_n_u8(tag));
              const uint8x16_t equalMask1 = vceqq_u8(chunk1, vdupq_n_u8(tag));
              const int8x8_t pack0 = vqmovn_s16(vreinterpretq_s16_u8(equalMask0));
              const int8x8_t pack1 = vqmovn_s16(vreinterpretq_s16_u8(equalMask1));
              const uint8x8_t t0 = vreinterpret_u8_s8(pack0);
              const uint8x8_t t1 = vreinterpret_u8_s8(pack1);
              const uint8x8_t t2 = vsri_n_u8(t1, t0, 2);
              const uint8x8x2_t t3 = vuzp_u8(t2, t0);
              const uint8x8_t t4 = vsri_n_u8(t3.val[1], t3.val[0], 4);
              const U32 matches = vget_lane_u32(vreinterpret_u32_u8(t4), 0);
              return ZSTD_rotateRight_U32(matches, head);
          } else { /* rowEntries == 64 */
              const uint8x16x4_t chunk = vld4q_u8(src);
              const uint8x16_t dup = vdupq_n_u8(tag);
              const uint8x16_t cmp0 = vceqq_u8(chunk.val[0], dup);
              const uint8x16_t cmp1 = vceqq_u8(chunk.val[1], dup);
              const uint8x16_t cmp2 = vceqq_u8(chunk.val[2], dup);
              const uint8x16_t cmp3 = vceqq_u8(chunk.val[3], dup);
  
              const uint8x16_t t0 = vsriq_n_u8(cmp1, cmp0, 1);
              const uint8x16_t t1 = vsriq_n_u8(cmp3, cmp2, 1);
              const uint8x16_t t2 = vsriq_n_u8(t1, t0, 2);
              const uint8x16_t t3 = vsriq_n_u8(t2, t2, 4);
              const uint8x8_t t4 = vshrn_n_u16(vreinterpretq_u16_u8(t3), 4);
              const U64 matches = vget_lane_u64(vreinterpret_u64_u8(t4), 0);
              return ZSTD_rotateRight_U64(matches, head);
          }
      }
  # endif /* ZSTD_ARCH_ARM_NEON */
      /* SWAR */
      {   const size_t chunkSize = sizeof(size_t);
          const size_t shiftAmount = ((chunkSize * 8) - chunkSize);
          const size_t xFF = ~((size_t)0);
          const size_t x01 = xFF / 0xFF;
          const size_t x80 = x01 << 7;
          const size_t splatChar = tag * x01;
          ZSTD_VecMask matches = 0;
          int i = rowEntries - chunkSize;
          assert((sizeof(size_t) == 4) || (sizeof(size_t) == 8));
          if (MEM_isLittleEndian()) { /* runtime check so have two loops */
              const size_t extractMagic = (xFF / 0x7F) >> chunkSize;
              do {
                  size_t chunk = MEM_readST(&src[i]);
                  chunk ^= splatChar;
                  chunk = (((chunk | x80) - x01) | chunk) & x80;
                  matches <<= chunkSize;
                  matches |= (chunk * extractMagic) >> shiftAmount;
                  i -= chunkSize;
              } while (i >= 0);
          } else { /* big endian: reverse bits during extraction */
              const size_t msb = xFF ^ (xFF >> 1);
              const size_t extractMagic = (msb / 0x1FF) | msb;
              do {
                  size_t chunk = MEM_readST(&src[i]);
                  chunk ^= splatChar;
                  chunk = (((chunk | x80) - x01) | chunk) & x80;
                  matches <<= chunkSize;
                  matches |= ((chunk >> 7) * extractMagic) >> shiftAmount;
                  i -= chunkSize;
              } while (i >= 0);
          }
          matches = ~matches;
          if (rowEntries == 16) {
              return ZSTD_rotateRight_U16((U16)matches, head);
          } else if (rowEntries == 32) {
              return ZSTD_rotateRight_U32((U32)matches, head);
          } else {
              return ZSTD_rotateRight_U64((U64)matches, head);
          }
      }
  #endif
  }
  
  /* The high-level approach of the SIMD row based match finder is as follows:
   * - Figure out where to insert the new entry:
   *      - Generate a hash from a byte along with an additional 1-byte "short hash". The additional byte is our "tag"
   *      - The hashTable is effectively split into groups or "rows" of 16 or 32 entries of U32, and the hash determines
   *        which row to insert into.
   *      - Determine the correct position within the row to insert the entry into. Each row of 16 or 32 can
   *        be considered as a circular buffer with a "head" index that resides in the tagTable.
   *      - Also insert the "tag" into the equivalent row and position in the tagTable.
   *          - Note: The tagTable has 17 or 33 1-byte entries per row, due to 16 or 32 tags, and 1 "head" entry.
   *                  The 17 or 33 entry rows are spaced out to occur every 32 or 64 bytes, respectively,
   *                  for alignment/performance reasons, leaving some bytes unused.
   * - Use SIMD to efficiently compare the tags in the tagTable to the 1-byte "short hash" and
   *   generate a bitfield that we can cycle through to check the collisions in the hash table.
   * - Pick the longest match.
   */
  FORCE_INLINE_TEMPLATE
  size_t ZSTD_RowFindBestMatch(
                          ZSTD_matchState_t* ms,
                          const BYTE* const ip, const BYTE* const iLimit,
                          size_t* offsetPtr,
                          const U32 mls, const ZSTD_dictMode_e dictMode,
                          const U32 rowLog)
  {
      U32* const hashTable = ms->hashTable;
      U16* const tagTable = ms->tagTable;
      U32* const hashCache = ms->hashCache;
      const U32 hashLog = ms->rowHashLog;
      const ZSTD_compressionParameters* const cParams = &ms->cParams;
      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 curr = (U32)(ip-base);
      const U32 maxDistance = 1U << cParams->windowLog;
      const U32 lowestValid = ms->window.lowLimit;
      const U32 withinMaxDistance = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
      const U32 isDictionary = (ms->loadedDictEnd != 0);
      const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance;
      const U32 rowEntries = (1U << rowLog);
      const U32 rowMask = rowEntries - 1;
      const U32 cappedSearchLog = MIN(cParams->searchLog, rowLog); /* nb of searches is capped at nb entries per row */
      U32 nbAttempts = 1U << cappedSearchLog;
      size_t ml=4-1;
  
      /* DMS/DDS variables that may be referenced laster */
      const ZSTD_matchState_t* const dms = ms->dictMatchState;
  
      /* Initialize the following variables to satisfy static analyzer */
      size_t ddsIdx = 0;
      U32 ddsExtraAttempts = 0; /* cctx hash tables are limited in searches, but allow extra searches into DDS */
      U32 dmsTag = 0;
      U32* dmsRow = NULL;
      BYTE* dmsTagRow = NULL;
  
      if (dictMode == ZSTD_dedicatedDictSearch) {
          const U32 ddsHashLog = dms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG;
          {   /* Prefetch DDS hashtable entry */
              ddsIdx = ZSTD_hashPtr(ip, ddsHashLog, mls) << ZSTD_LAZY_DDSS_BUCKET_LOG;
              PREFETCH_L1(&dms->hashTable[ddsIdx]);
          }
          ddsExtraAttempts = cParams->searchLog > rowLog ? 1U << (cParams->searchLog - rowLog) : 0;
      }
  
      if (dictMode == ZSTD_dictMatchState) {
          /* Prefetch DMS rows */
          U32* const dmsHashTable = dms->hashTable;
          U16* const dmsTagTable = dms->tagTable;
          U32 const dmsHash = (U32)ZSTD_hashPtr(ip, dms->rowHashLog + ZSTD_ROW_HASH_TAG_BITS, mls);
          U32 const dmsRelRow = (dmsHash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
          dmsTag = dmsHash & ZSTD_ROW_HASH_TAG_MASK;
          dmsTagRow = (BYTE*)(dmsTagTable + dmsRelRow);
          dmsRow = dmsHashTable + dmsRelRow;
          ZSTD_row_prefetch(dmsHashTable, dmsTagTable, dmsRelRow, rowLog);
      }
  
      /* Update the hashTable and tagTable up to (but not including) ip */
      ZSTD_row_update_internal(ms, ip, mls, rowLog, rowMask, 1 /* useCache */);
      {   /* Get the hash for ip, compute the appropriate row */
          U32 const hash = ZSTD_row_nextCachedHash(hashCache, hashTable, tagTable, base, curr, hashLog, rowLog, mls);
          U32 const relRow = (hash >> ZSTD_ROW_HASH_TAG_BITS) << rowLog;
          U32 const tag = hash & ZSTD_ROW_HASH_TAG_MASK;
          U32* const row = hashTable + relRow;
          BYTE* tagRow = (BYTE*)(tagTable + relRow);
          U32 const head = *tagRow & rowMask;
          U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES];
          size_t numMatches = 0;
          size_t currMatch = 0;
          ZSTD_VecMask matches = ZSTD_row_getMatchMask(tagRow, (BYTE)tag, head, rowEntries);
  
          /* Cycle through the matches and prefetch */
          for (; (matches > 0) && (nbAttempts > 0); --nbAttempts, matches &= (matches - 1)) {
              U32 const matchPos = (head + ZSTD_VecMask_next(matches)) & rowMask;
              U32 const matchIndex = row[matchPos];
              assert(numMatches < rowEntries);
              if (matchIndex < lowLimit)
                  break;
              if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) {
                  PREFETCH_L1(base + matchIndex);
              } else {
                  PREFETCH_L1(dictBase + matchIndex);
              }
              matchBuffer[numMatches++] = matchIndex;
          }
  
          /* Speed opt: insert current byte into hashtable too. This allows us to avoid one iteration of the loop
             in ZSTD_row_update_internal() at the next search. */
          {
              U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask);
              tagRow[pos + ZSTD_ROW_HASH_TAG_OFFSET] = (BYTE)tag;
              row[pos] = ms->nextToUpdate++;
          }
  
          /* Return the longest match */
          for (; currMatch < numMatches; ++currMatch) {
              U32 const matchIndex = matchBuffer[currMatch];
              size_t currentMl=0;
              assert(matchIndex < curr);
              assert(matchIndex >= lowLimit);
  
              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 = STORE_OFFSET(curr - matchIndex);
                  if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */
              }
          }
      }
  
      assert(nbAttempts <= (1U << ZSTD_SEARCHLOG_MAX)); /* Check we haven't underflowed. */
      if (dictMode == ZSTD_dedicatedDictSearch) {
          ml = ZSTD_dedicatedDictSearch_lazy_search(offsetPtr, ml, nbAttempts + ddsExtraAttempts, dms,
                                                    ip, iLimit, prefixStart, curr, dictLimit, ddsIdx);
      } else if (dictMode == ZSTD_dictMatchState) {
          /* TODO: Measure and potentially add prefetching to DMS */
          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;
  
          {   U32 const head = *dmsTagRow & rowMask;
              U32 matchBuffer[ZSTD_ROW_HASH_MAX_ENTRIES];
              size_t numMatches = 0;
              size_t currMatch = 0;
              ZSTD_VecMask matches = ZSTD_row_getMatchMask(dmsTagRow, (BYTE)dmsTag, head, rowEntries);
  
              for (; (matches > 0) && (nbAttempts > 0); --nbAttempts, matches &= (matches - 1)) {
                  U32 const matchPos = (head + ZSTD_VecMask_next(matches)) & rowMask;
                  U32 const matchIndex = dmsRow[matchPos];
                  if (matchIndex < dmsLowestIndex)
                      break;
                  PREFETCH_L1(dmsBase + matchIndex);
                  matchBuffer[numMatches++] = matchIndex;
              }
  
              /* Return the longest match */
              for (; currMatch < numMatches; ++currMatch) {
                  U32 const matchIndex = matchBuffer[currMatch];
                  size_t currentMl=0;
                  assert(matchIndex >= dmsLowestIndex);
                  assert(matchIndex < curr);
  
                  {   const BYTE* const match = dmsBase + matchIndex;
                      assert(match+4 <= dmsEnd);
                      if (MEM_read32(match) == MEM_read32(ip))
                          currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4;
                  }
  
                  if (currentMl > ml) {
                      ml = currentMl;
                      assert(curr > matchIndex + dmsIndexDelta);
                      *offsetPtr = STORE_OFFSET(curr - (matchIndex + dmsIndexDelta));
                      if (ip+currentMl == iLimit) break;
                  }
              }
          }
      }
      return ml;
  }
  
  
  typedef size_t (*searchMax_f)(
                      ZSTD_matchState_t* ms,
                      const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr);
  
  /**
   * This struct contains the functions necessary for lazy to search.
   * Currently, that is only searchMax. However, it is still valuable to have the
   * VTable because this makes it easier to add more functions to the VTable later.
   *
   * TODO: The start of the search function involves loading and calculating a
   * bunch of constants from the ZSTD_matchState_t. These computations could be
   * done in an initialization function, and saved somewhere in the match state.
   * Then we could pass a pointer to the saved state instead of the match state,
   * and avoid duplicate computations.
   *
   * TODO: Move the match re-winding into searchMax. This improves compression
   * ratio, and unlocks further simplifications with the next TODO.
   *
   * TODO: Try moving the repcode search into searchMax. After the re-winding
   * and repcode search are in searchMax, there is no more logic in the match
   * finder loop that requires knowledge about the dictMode. So we should be
   * able to avoid force inlining it, and we can join the extDict loop with
   * the single segment loop. It should go in searchMax instead of its own
   * function to avoid having multiple virtual function calls per search.
   */
  typedef struct {
      searchMax_f searchMax;
  } ZSTD_LazyVTable;
  
  #define GEN_ZSTD_BT_VTABLE(dictMode, mls)                                             \
      static size_t ZSTD_BtFindBestMatch_##dictMode##_##mls(                            \
              ZSTD_matchState_t* ms,                                                    \
              const BYTE* ip, const BYTE* const iLimit,                                 \
              size_t* offsetPtr)                                                        \
      {                                                                                 \
          assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls);                          \
          return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode); \
      }                                                                                 \
      static const ZSTD_LazyVTable ZSTD_BtVTable_##dictMode##_##mls = {                 \
          ZSTD_BtFindBestMatch_##dictMode##_##mls                                       \
      };
  
  #define GEN_ZSTD_HC_VTABLE(dictMode, mls)                                             \
      static size_t ZSTD_HcFindBestMatch_##dictMode##_##mls(                            \
              ZSTD_matchState_t* ms,                                                    \
              const BYTE* ip, const BYTE* const iLimit,                                 \
              size_t* offsetPtr)                                                        \
      {                                                                                 \
          assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls);                          \
          return ZSTD_HcFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode); \
      }                                                                                 \
      static const ZSTD_LazyVTable ZSTD_HcVTable_##dictMode##_##mls = {                 \
          ZSTD_HcFindBestMatch_##dictMode##_##mls                                       \
      };
  
  #define GEN_ZSTD_ROW_VTABLE(dictMode, mls, rowLog)                                             \
      static size_t ZSTD_RowFindBestMatch_##dictMode##_##mls##_##rowLog(                         \
              ZSTD_matchState_t* ms,                                                             \
              const BYTE* ip, const BYTE* const iLimit,                                          \
              size_t* offsetPtr)                                                                 \
      {                                                                                          \
          assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls);                                   \
          assert(MAX(4, MIN(6, ms->cParams.searchLog)) == rowLog);                               \
          return ZSTD_RowFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode, rowLog); \
      }                                                                                          \
      static const ZSTD_LazyVTable ZSTD_RowVTable_##dictMode##_##mls##_##rowLog = {              \
          ZSTD_RowFindBestMatch_##dictMode##_##mls##_##rowLog                                    \
      };
  
  #define ZSTD_FOR_EACH_ROWLOG(X, dictMode, mls) \
      X(dictMode, mls, 4)                        \
      X(dictMode, mls, 5)                        \
      X(dictMode, mls, 6)
  
  #define ZSTD_FOR_EACH_MLS_ROWLOG(X, dictMode) \
      ZSTD_FOR_EACH_ROWLOG(X, dictMode, 4)      \
      ZSTD_FOR_EACH_ROWLOG(X, dictMode, 5)      \
      ZSTD_FOR_EACH_ROWLOG(X, dictMode, 6)
  
  #define ZSTD_FOR_EACH_MLS(X, dictMode) \
      X(dictMode, 4)                     \
      X(dictMode, 5)                     \
      X(dictMode, 6)
  
  #define ZSTD_FOR_EACH_DICT_MODE(X, ...) \
      X(__VA_ARGS__, noDict)              \
      X(__VA_ARGS__, extDict)             \
      X(__VA_ARGS__, dictMatchState)      \
      X(__VA_ARGS__, dedicatedDictSearch)
  
  /* Generate Row VTables for each combination of (dictMode, mls, rowLog) */
  ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS_ROWLOG, GEN_ZSTD_ROW_VTABLE)
  /* Generate Binary Tree VTables for each combination of (dictMode, mls) */
  ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_BT_VTABLE)
  /* Generate Hash Chain VTables for each combination of (dictMode, mls) */
  ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_HC_VTABLE)
  
  #define GEN_ZSTD_BT_VTABLE_ARRAY(dictMode) \
      {                                      \
          &ZSTD_BtVTable_##dictMode##_4,     \
          &ZSTD_BtVTable_##dictMode##_5,     \
          &ZSTD_BtVTable_##dictMode##_6      \
      }
  
  #define GEN_ZSTD_HC_VTABLE_ARRAY(dictMode) \
      {                                      \
          &ZSTD_HcVTable_##dictMode##_4,     \
          &ZSTD_HcVTable_##dictMode##_5,     \
          &ZSTD_HcVTable_##dictMode##_6      \
      }
  
  #define GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, mls) \
      {                                             \
          &ZSTD_RowVTable_##dictMode##_##mls##_4,   \
          &ZSTD_RowVTable_##dictMode##_##mls##_5,   \
          &ZSTD_RowVTable_##dictMode##_##mls##_6    \
      }
  
  #define GEN_ZSTD_ROW_VTABLE_ARRAY(dictMode)      \
      {                                            \
          GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, 4), \
          GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, 5), \
          GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, 6)  \
      }
  
  #define GEN_ZSTD_VTABLE_ARRAY(X) \
      {                            \
          X(noDict),               \
          X(extDict),              \
          X(dictMatchState),       \
          X(dedicatedDictSearch)   \
      }
  
  /* *******************************
  *  Common parser - lazy strategy
  *********************************/
  typedef enum { search_hashChain=0, search_binaryTree=1, search_rowHash=2 } searchMethod_e;
  
  /**
   * This table is indexed first by the four ZSTD_dictMode_e values, and then
   * by the two searchMethod_e values. NULLs are placed for configurations
   * that should never occur (extDict modes go to the other implementation
   * below and there is no DDSS for binary tree search yet).
   */
  
  static ZSTD_LazyVTable const*
  ZSTD_selectLazyVTable(ZSTD_matchState_t const* ms, searchMethod_e searchMethod, ZSTD_dictMode_e dictMode)
  {
      /* Fill the Hc/Bt VTable arrays with the right functions for the (dictMode, mls) combination. */
      ZSTD_LazyVTable const* const hcVTables[4][3] = GEN_ZSTD_VTABLE_ARRAY(GEN_ZSTD_HC_VTABLE_ARRAY);
      ZSTD_LazyVTable const* const btVTables[4][3] = GEN_ZSTD_VTABLE_ARRAY(GEN_ZSTD_BT_VTABLE_ARRAY);
      /* Fill the Row VTable array with the right functions for the (dictMode, mls, rowLog) combination. */
      ZSTD_LazyVTable const* const rowVTables[4][3][3] = GEN_ZSTD_VTABLE_ARRAY(GEN_ZSTD_ROW_VTABLE_ARRAY);
  
      U32 const mls = MAX(4, MIN(6, ms->cParams.minMatch));
      U32 const rowLog = MAX(4, MIN(6, ms->cParams.searchLog));
      switch (searchMethod) {
          case search_hashChain:
              return hcVTables[dictMode][mls - 4];
          case search_binaryTree:
              return btVTables[dictMode][mls - 4];
          case search_rowHash:
              return rowVTables[dictMode][mls - 4][rowLog - 4];
          default:
              return NULL;
      }
  }
  
  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 = (searchMethod == search_rowHash) ? iend - 8 - ZSTD_ROW_HASH_CACHE_SIZE : iend - 8;
      const BYTE* const base = ms->window.base;
      const U32 prefixLowestIndex = ms->window.dictLimit;
      const BYTE* const prefixLowest = base + prefixLowestIndex;
  
      searchMax_f const searchMax = ZSTD_selectLazyVTable(ms, searchMethod, dictMode)->searchMax;
      U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0;
  
      const int isDMS = dictMode == ZSTD_dictMatchState;
      const int isDDS = dictMode == ZSTD_dedicatedDictSearch;
      const int isDxS = isDMS || isDDS;
      const ZSTD_matchState_t* const dms = ms->dictMatchState;
      const U32 dictLowestIndex      = isDxS ? dms->window.dictLimit : 0;
      const BYTE* const dictBase     = isDxS ? dms->window.base : NULL;
      const BYTE* const dictLowest   = isDxS ? dictBase + dictLowestIndex : NULL;
      const BYTE* const dictEnd      = isDxS ? dms->window.nextSrc : NULL;
      const U32 dictIndexDelta       = isDxS ?
                                       prefixLowestIndex - (U32)(dictEnd - dictBase) :
                                       0;
      const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest));
  
      assert(searchMax != NULL);
  
      DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u) (searchFunc=%u)", (U32)dictMode, (U32)searchMethod);
      ip += (dictAndPrefixLength == 0);
      if (dictMode == ZSTD_noDict) {
          U32 const curr = (U32)(ip - base);
          U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, ms->cParams.windowLog);
          U32 const maxRep = curr - windowLow;
          if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
          if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
      }
      if (isDxS) {
          /* dictMatchState repCode checks don't currently handle repCode == 0
           * disabling. */
          assert(offset_1 <= dictAndPrefixLength);
          assert(offset_2 <= dictAndPrefixLength);
      }
  
      if (searchMethod == search_rowHash) {
          const U32 rowLog = MAX(4, MIN(6, ms->cParams.searchLog));
          ZSTD_row_fillHashCache(ms, base, rowLog,
                              MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */),
                              ms->nextToUpdate, ilimit);
      }
  
      /* 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 offcode=STORE_REPCODE_1;
          const BYTE* start=ip+1;
          DEBUGLOG(7, "search baseline (depth 0)");
  
          /* check repCode */
          if (isDxS) {
              const U32 repIndex = (U32)(ip - base) + 1 - offset_1;
              const BYTE* repMatch = ((dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch)
                                  && 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, offcode=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) {
              DEBUGLOG(7, "search depth 1");
              ip ++;
              if ( (dictMode == ZSTD_noDict)
                && (offcode) && ((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)STORED_TO_OFFBASE(offcode)) + 1);
                  if ((mlRep >= 4) && (gain2 > gain1))
                      matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
              }
              if (isDxS) {
                  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)STORED_TO_OFFBASE(offcode)) + 1);
                      if ((mlRep >= 4) && (gain2 > gain1))
                          matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
                  }
              }
              {   size_t offset2=999999999;
                  size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                  int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offset2)));   /* raw approx */
                  int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 4);
                  if ((ml2 >= 4) && (gain2 > gain1)) {
                      matchLength = ml2, offcode = offset2, start = ip;
                      continue;   /* search a better one */
              }   }
  
              /* let's find an even better one */
              if ((depth==2) && (ip<ilimit)) {
                  DEBUGLOG(7, "search depth 2");
                  ip ++;
                  if ( (dictMode == ZSTD_noDict)
                    && (offcode) && ((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)STORED_TO_OFFBASE(offcode)) + 1);
                      if ((mlRep >= 4) && (gain2 > gain1))
                          matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
                  }
                  if (isDxS) {
                      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)STORED_TO_OFFBASE(offcode)) + 1);
                          if ((mlRep >= 4) && (gain2 > gain1))
                              matchLength = mlRep, offcode = STORE_REPCODE_1, start = ip;
                      }
                  }
                  {   size_t offset2=999999999;
                      size_t const ml2 = searchMax(ms, ip, iend, &offset2);
                      int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offset2)));   /* raw approx */
                      int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 7);
                      if ((ml2 >= 4) && (gain2 > gain1)) {
                          matchLength = ml2, offcode = offset2, start = ip;
                          continue;
              }   }   }
              break;  /* nothing found : store previous solution */
          }
  
          /* NOTE:
           * Pay attention that `start[-value]` can lead to strange undefined behavior
           * notably if `value` is unsigned, resulting in a large positive `-value`.
           */
          /* catch up */
          if (STORED_IS_OFFSET(offcode)) {
              if (dictMode == ZSTD_noDict) {
                  while ( ((start > anchor) & (start - STORED_OFFSET(offcode) > prefixLowest))
                       && (start[-1] == (start-STORED_OFFSET(offcode))[-1]) )  /* only search for offset within prefix */
                      { start--; matchLength++; }
              }
              if (isDxS) {
                  U32 const matchIndex = (U32)((size_t)(start-base) - STORED_OFFSET(offcode));
                  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)STORED_OFFSET(offcode);
          }
          /* store sequence */
  _storeSequence:
          {   size_t const litLength = (size_t)(start - anchor);
              ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offcode, matchLength);
              anchor = ip = start + matchLength;
          }
  
          /* check immediate repcode */
          if (isDxS) {
              while (ip <= ilimit) {
                  U32 const current2 = (U32)(ip-base);
                  U32 const repIndex = current2 - offset_2;
                  const BYTE* repMatch = 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;
                      offcode = offset_2; offset_2 = offset_1; offset_1 = (U32)offcode;   /* swap offset_2 <=> offset_1 */
                      ZSTD_storeSeq(seqStore, 0, anchor, iend, STORE_REPCODE_1, matchLength);
                      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;
                  offcode = offset_2; offset_2 = offset_1; offset_1 = (U32)offcode; /* swap repcodes */
                  ZSTD_storeSeq(seqStore, 0, anchor, iend, STORE_REPCODE_1, matchLength);
                  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);
  }
  
  
  size_t ZSTD_compressBlock_lazy2_dedicatedDictSearch(
          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_dedicatedDictSearch);
  }
  
  size_t ZSTD_compressBlock_lazy_dedicatedDictSearch(
          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_dedicatedDictSearch);
  }
  
  size_t ZSTD_compressBlock_greedy_dedicatedDictSearch(
          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_dedicatedDictSearch);
  }
  
  /* Row-based matchfinder */
  size_t ZSTD_compressBlock_lazy2_row(
          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_rowHash, 2, ZSTD_noDict);
  }
  
  size_t ZSTD_compressBlock_lazy_row(
          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_rowHash, 1, ZSTD_noDict);
  }
  
  size_t ZSTD_compressBlock_greedy_row(
          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_rowHash, 0, ZSTD_noDict);
  }
  
  size_t ZSTD_compressBlock_lazy2_dictMatchState_row(
          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_rowHash, 2, ZSTD_dictMatchState);
  }
  
  size_t ZSTD_compressBlock_lazy_dictMatchState_row(
          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_rowHash, 1, ZSTD_dictMatchState);
  }
  
  size_t ZSTD_compressBlock_greedy_dictMatchState_row(
          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_rowHash, 0, ZSTD_dictMatchState);
  }
  
  
  size_t ZSTD_compressBlock_lazy2_dedicatedDictSearch_row(
          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_rowHash, 2, ZSTD_dedicatedDictSearch);
  }
  
  size_t ZSTD_compressBlock_lazy_dedicatedDictSearch_row(
          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_rowHash, 1, ZSTD_dedicatedDictSearch);
  }
  
  size_t ZSTD_compressBlock_greedy_dedicatedDictSearch_row(
          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_rowHash, 0, ZSTD_dedicatedDictSearch);
  }
  
  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 = searchMethod == search_rowHash ? iend - 8 - ZSTD_ROW_HASH_CACHE_SIZE : 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;
      const U32 rowLog = ms->cParams.searchLog < 5 ? 4 : 5;
  
      searchMax_f const searchMax = ZSTD_selectLazyVTable(ms, searchMethod, ZSTD_extDict)->searchMax;
      U32 offset_1 = rep[0], offset_2 = rep[1];
  
      DEBUGLOG(5, "ZSTD_compressBlock_lazy_extDict_generic (searchFunc=%u)", (U32)searchMethod);
  
      /* init */
      ip += (ip == prefixStart);
      if (searchMethod == search_rowHash) {
          ZSTD_row_fillHashCache(ms, base, rowLog,
                                 MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */),
                                 ms->nextToUpdate, ilimit);
      }
  
      /* 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 offcode=STORE_REPCODE_1;
          const BYTE* start=ip+1;
          U32 curr = (U32)(ip-base);
  
          /* check repCode */
          {   const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr+1, windowLog);
              const U32 repIndex = (U32)(curr+1 - offset_1);
              const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
              const BYTE* const repMatch = repBase + repIndex;
              if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
                 & (offset_1 <= curr+1 - windowLow) ) /* note: we are searching at curr+1 */
              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, offcode=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 ++;
              curr++;
              /* check repCode */
              if (offcode) {
                  const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog);
                  const U32 repIndex = (U32)(curr - offset_1);
                  const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
                  const BYTE* const repMatch = repBase + repIndex;
                  if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments  */
                     & (offset_1 <= curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
                  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)STORED_TO_OFFBASE(offcode)) + 1);
                      if ((repLength >= 4) && (gain2 > gain1))
                          matchLength = repLength, offcode = STORE_REPCODE_1, 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)STORED_TO_OFFBASE(offset2)));   /* raw approx */
                  int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 4);
                  if ((ml2 >= 4) && (gain2 > gain1)) {
                      matchLength = ml2, offcode = offset2, start = ip;
                      continue;   /* search a better one */
              }   }
  
              /* let's find an even better one */
              if ((depth==2) && (ip<ilimit)) {
                  ip ++;
                  curr++;
                  /* check repCode */
                  if (offcode) {
                      const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog);
                      const U32 repIndex = (U32)(curr - offset_1);
                      const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
                      const BYTE* const repMatch = repBase + repIndex;
                      if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments  */
                         & (offset_1 <= curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
                      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)STORED_TO_OFFBASE(offcode)) + 1);
                          if ((repLength >= 4) && (gain2 > gain1))
                              matchLength = repLength, offcode = STORE_REPCODE_1, 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)STORED_TO_OFFBASE(offset2)));   /* raw approx */
                      int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)STORED_TO_OFFBASE(offcode)) + 7);
                      if ((ml2 >= 4) && (gain2 > gain1)) {
                          matchLength = ml2, offcode = offset2, start = ip;
                          continue;
              }   }   }
              break;  /* nothing found : store previous solution */
          }
  
          /* catch up */
          if (STORED_IS_OFFSET(offcode)) {
              U32 const matchIndex = (U32)((size_t)(start-base) - STORED_OFFSET(offcode));
              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)STORED_OFFSET(offcode);
          }
  
          /* store sequence */
  _storeSequence:
          {   size_t const litLength = (size_t)(start - anchor);
              ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offcode, matchLength);
              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) /* intentional overflow : do not test positions overlapping 2 memory segments  */
                 & (offset_2 <= repCurrent - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
              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;
                  offcode = offset_2; offset_2 = offset_1; offset_1 = (U32)offcode;   /* swap offset history */
                  ZSTD_storeSeq(seqStore, 0, anchor, iend, STORE_REPCODE_1, matchLength);
                  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);
  }
  
  size_t ZSTD_compressBlock_greedy_extDict_row(
          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_rowHash, 0);
  }
  
  size_t ZSTD_compressBlock_lazy_extDict_row(
          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_rowHash, 1);
  }
  
  size_t ZSTD_compressBlock_lazy2_extDict_row(
          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_rowHash, 2);
  }

Cache object: 7b3a08be4e1af1ac7fdd0376b808169c