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0001 /*
0002  * Copyright (c) Yann Collet, Facebook, Inc.
0003  * All rights reserved.
0004  *
0005  * This source code is licensed under both the BSD-style license (found in the
0006  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
0007  * in the COPYING file in the root directory of this source tree).
0008  * You may select, at your option, one of the above-listed licenses.
0009  */
0010 
0011 #include "zstd_compress_internal.h"
0012 #include "zstd_double_fast.h"
0013 
0014 
0015 void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms,
0016                               void const* end, ZSTD_dictTableLoadMethod_e dtlm)
0017 {
0018     const ZSTD_compressionParameters* const cParams = &ms->cParams;
0019     U32* const hashLarge = ms->hashTable;
0020     U32  const hBitsL = cParams->hashLog;
0021     U32  const mls = cParams->minMatch;
0022     U32* const hashSmall = ms->chainTable;
0023     U32  const hBitsS = cParams->chainLog;
0024     const BYTE* const base = ms->window.base;
0025     const BYTE* ip = base + ms->nextToUpdate;
0026     const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
0027     const U32 fastHashFillStep = 3;
0028 
0029     /* Always insert every fastHashFillStep position into the hash tables.
0030      * Insert the other positions into the large hash table if their entry
0031      * is empty.
0032      */
0033     for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) {
0034         U32 const curr = (U32)(ip - base);
0035         U32 i;
0036         for (i = 0; i < fastHashFillStep; ++i) {
0037             size_t const smHash = ZSTD_hashPtr(ip + i, hBitsS, mls);
0038             size_t const lgHash = ZSTD_hashPtr(ip + i, hBitsL, 8);
0039             if (i == 0)
0040                 hashSmall[smHash] = curr + i;
0041             if (i == 0 || hashLarge[lgHash] == 0)
0042                 hashLarge[lgHash] = curr + i;
0043             /* Only load extra positions for ZSTD_dtlm_full */
0044             if (dtlm == ZSTD_dtlm_fast)
0045                 break;
0046     }   }
0047 }
0048 
0049 
0050 FORCE_INLINE_TEMPLATE
0051 size_t ZSTD_compressBlock_doubleFast_generic(
0052         ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
0053         void const* src, size_t srcSize,
0054         U32 const mls /* template */, ZSTD_dictMode_e const dictMode)
0055 {
0056     ZSTD_compressionParameters const* cParams = &ms->cParams;
0057     U32* const hashLong = ms->hashTable;
0058     const U32 hBitsL = cParams->hashLog;
0059     U32* const hashSmall = ms->chainTable;
0060     const U32 hBitsS = cParams->chainLog;
0061     const BYTE* const base = ms->window.base;
0062     const BYTE* const istart = (const BYTE*)src;
0063     const BYTE* ip = istart;
0064     const BYTE* anchor = istart;
0065     const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
0066     /* presumes that, if there is a dictionary, it must be using Attach mode */
0067     const U32 prefixLowestIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
0068     const BYTE* const prefixLowest = base + prefixLowestIndex;
0069     const BYTE* const iend = istart + srcSize;
0070     const BYTE* const ilimit = iend - HASH_READ_SIZE;
0071     U32 offset_1=rep[0], offset_2=rep[1];
0072     U32 offsetSaved = 0;
0073 
0074     const ZSTD_matchState_t* const dms = ms->dictMatchState;
0075     const ZSTD_compressionParameters* const dictCParams =
0076                                      dictMode == ZSTD_dictMatchState ?
0077                                      &dms->cParams : NULL;
0078     const U32* const dictHashLong  = dictMode == ZSTD_dictMatchState ?
0079                                      dms->hashTable : NULL;
0080     const U32* const dictHashSmall = dictMode == ZSTD_dictMatchState ?
0081                                      dms->chainTable : NULL;
0082     const U32 dictStartIndex       = dictMode == ZSTD_dictMatchState ?
0083                                      dms->window.dictLimit : 0;
0084     const BYTE* const dictBase     = dictMode == ZSTD_dictMatchState ?
0085                                      dms->window.base : NULL;
0086     const BYTE* const dictStart    = dictMode == ZSTD_dictMatchState ?
0087                                      dictBase + dictStartIndex : NULL;
0088     const BYTE* const dictEnd      = dictMode == ZSTD_dictMatchState ?
0089                                      dms->window.nextSrc : NULL;
0090     const U32 dictIndexDelta       = dictMode == ZSTD_dictMatchState ?
0091                                      prefixLowestIndex - (U32)(dictEnd - dictBase) :
0092                                      0;
0093     const U32 dictHBitsL           = dictMode == ZSTD_dictMatchState ?
0094                                      dictCParams->hashLog : hBitsL;
0095     const U32 dictHBitsS           = dictMode == ZSTD_dictMatchState ?
0096                                      dictCParams->chainLog : hBitsS;
0097     const U32 dictAndPrefixLength  = (U32)((ip - prefixLowest) + (dictEnd - dictStart));
0098 
0099     DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_generic");
0100 
0101     assert(dictMode == ZSTD_noDict || dictMode == ZSTD_dictMatchState);
0102 
0103     /* if a dictionary is attached, it must be within window range */
0104     if (dictMode == ZSTD_dictMatchState) {
0105         assert(ms->window.dictLimit + (1U << cParams->windowLog) >= endIndex);
0106     }
0107 
0108     /* init */
0109     ip += (dictAndPrefixLength == 0);
0110     if (dictMode == ZSTD_noDict) {
0111         U32 const curr = (U32)(ip - base);
0112         U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog);
0113         U32 const maxRep = curr - windowLow;
0114         if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
0115         if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
0116     }
0117     if (dictMode == ZSTD_dictMatchState) {
0118         /* dictMatchState repCode checks don't currently handle repCode == 0
0119          * disabling. */
0120         assert(offset_1 <= dictAndPrefixLength);
0121         assert(offset_2 <= dictAndPrefixLength);
0122     }
0123 
0124     /* Main Search Loop */
0125     while (ip < ilimit) {   /* < instead of <=, because repcode check at (ip+1) */
0126         size_t mLength;
0127         U32 offset;
0128         size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
0129         size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
0130         size_t const dictHL = ZSTD_hashPtr(ip, dictHBitsL, 8);
0131         size_t const dictHS = ZSTD_hashPtr(ip, dictHBitsS, mls);
0132         U32 const curr = (U32)(ip-base);
0133         U32 const matchIndexL = hashLong[h2];
0134         U32 matchIndexS = hashSmall[h];
0135         const BYTE* matchLong = base + matchIndexL;
0136         const BYTE* match = base + matchIndexS;
0137         const U32 repIndex = curr + 1 - offset_1;
0138         const BYTE* repMatch = (dictMode == ZSTD_dictMatchState
0139                             && repIndex < prefixLowestIndex) ?
0140                                dictBase + (repIndex - dictIndexDelta) :
0141                                base + repIndex;
0142         hashLong[h2] = hashSmall[h] = curr;   /* update hash tables */
0143 
0144         /* check dictMatchState repcode */
0145         if (dictMode == ZSTD_dictMatchState
0146             && ((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */)
0147             && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
0148             const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend;
0149             mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4;
0150             ip++;
0151             ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
0152             goto _match_stored;
0153         }
0154 
0155         /* check noDict repcode */
0156         if ( dictMode == ZSTD_noDict
0157           && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) {
0158             mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
0159             ip++;
0160             ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
0161             goto _match_stored;
0162         }
0163 
0164         if (matchIndexL > prefixLowestIndex) {
0165             /* check prefix long match */
0166             if (MEM_read64(matchLong) == MEM_read64(ip)) {
0167                 mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8;
0168                 offset = (U32)(ip-matchLong);
0169                 while (((ip>anchor) & (matchLong>prefixLowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
0170                 goto _match_found;
0171             }
0172         } else if (dictMode == ZSTD_dictMatchState) {
0173             /* check dictMatchState long match */
0174             U32 const dictMatchIndexL = dictHashLong[dictHL];
0175             const BYTE* dictMatchL = dictBase + dictMatchIndexL;
0176             assert(dictMatchL < dictEnd);
0177 
0178             if (dictMatchL > dictStart && MEM_read64(dictMatchL) == MEM_read64(ip)) {
0179                 mLength = ZSTD_count_2segments(ip+8, dictMatchL+8, iend, dictEnd, prefixLowest) + 8;
0180                 offset = (U32)(curr - dictMatchIndexL - dictIndexDelta);
0181                 while (((ip>anchor) & (dictMatchL>dictStart)) && (ip[-1] == dictMatchL[-1])) { ip--; dictMatchL--; mLength++; } /* catch up */
0182                 goto _match_found;
0183         }   }
0184 
0185         if (matchIndexS > prefixLowestIndex) {
0186             /* check prefix short match */
0187             if (MEM_read32(match) == MEM_read32(ip)) {
0188                 goto _search_next_long;
0189             }
0190         } else if (dictMode == ZSTD_dictMatchState) {
0191             /* check dictMatchState short match */
0192             U32 const dictMatchIndexS = dictHashSmall[dictHS];
0193             match = dictBase + dictMatchIndexS;
0194             matchIndexS = dictMatchIndexS + dictIndexDelta;
0195 
0196             if (match > dictStart && MEM_read32(match) == MEM_read32(ip)) {
0197                 goto _search_next_long;
0198         }   }
0199 
0200         ip += ((ip-anchor) >> kSearchStrength) + 1;
0201 #if defined(__aarch64__)
0202         PREFETCH_L1(ip+256);
0203 #endif
0204         continue;
0205 
0206 _search_next_long:
0207 
0208         {   size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
0209             size_t const dictHLNext = ZSTD_hashPtr(ip+1, dictHBitsL, 8);
0210             U32 const matchIndexL3 = hashLong[hl3];
0211             const BYTE* matchL3 = base + matchIndexL3;
0212             hashLong[hl3] = curr + 1;
0213 
0214             /* check prefix long +1 match */
0215             if (matchIndexL3 > prefixLowestIndex) {
0216                 if (MEM_read64(matchL3) == MEM_read64(ip+1)) {
0217                     mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
0218                     ip++;
0219                     offset = (U32)(ip-matchL3);
0220                     while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
0221                     goto _match_found;
0222                 }
0223             } else if (dictMode == ZSTD_dictMatchState) {
0224                 /* check dict long +1 match */
0225                 U32 const dictMatchIndexL3 = dictHashLong[dictHLNext];
0226                 const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3;
0227                 assert(dictMatchL3 < dictEnd);
0228                 if (dictMatchL3 > dictStart && MEM_read64(dictMatchL3) == MEM_read64(ip+1)) {
0229                     mLength = ZSTD_count_2segments(ip+1+8, dictMatchL3+8, iend, dictEnd, prefixLowest) + 8;
0230                     ip++;
0231                     offset = (U32)(curr + 1 - dictMatchIndexL3 - dictIndexDelta);
0232                     while (((ip>anchor) & (dictMatchL3>dictStart)) && (ip[-1] == dictMatchL3[-1])) { ip--; dictMatchL3--; mLength++; } /* catch up */
0233                     goto _match_found;
0234         }   }   }
0235 
0236         /* if no long +1 match, explore the short match we found */
0237         if (dictMode == ZSTD_dictMatchState && matchIndexS < prefixLowestIndex) {
0238             mLength = ZSTD_count_2segments(ip+4, match+4, iend, dictEnd, prefixLowest) + 4;
0239             offset = (U32)(curr - matchIndexS);
0240             while (((ip>anchor) & (match>dictStart)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
0241         } else {
0242             mLength = ZSTD_count(ip+4, match+4, iend) + 4;
0243             offset = (U32)(ip - match);
0244             while (((ip>anchor) & (match>prefixLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
0245         }
0246 
0247 _match_found:
0248         offset_2 = offset_1;
0249         offset_1 = offset;
0250 
0251         ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
0252 
0253 _match_stored:
0254         /* match found */
0255         ip += mLength;
0256         anchor = ip;
0257 
0258         if (ip <= ilimit) {
0259             /* Complementary insertion */
0260             /* done after iLimit test, as candidates could be > iend-8 */
0261             {   U32 const indexToInsert = curr+2;
0262                 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
0263                 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
0264                 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
0265                 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
0266             }
0267 
0268             /* check immediate repcode */
0269             if (dictMode == ZSTD_dictMatchState) {
0270                 while (ip <= ilimit) {
0271                     U32 const current2 = (U32)(ip-base);
0272                     U32 const repIndex2 = current2 - offset_2;
0273                     const BYTE* repMatch2 = dictMode == ZSTD_dictMatchState
0274                         && repIndex2 < prefixLowestIndex ?
0275                             dictBase + repIndex2 - dictIndexDelta :
0276                             base + repIndex2;
0277                     if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */)
0278                        && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
0279                         const BYTE* const repEnd2 = repIndex2 < prefixLowestIndex ? dictEnd : iend;
0280                         size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixLowest) + 4;
0281                         U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset;   /* swap offset_2 <=> offset_1 */
0282                         ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
0283                         hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
0284                         hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
0285                         ip += repLength2;
0286                         anchor = ip;
0287                         continue;
0288                     }
0289                     break;
0290             }   }
0291 
0292             if (dictMode == ZSTD_noDict) {
0293                 while ( (ip <= ilimit)
0294                      && ( (offset_2>0)
0295                         & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
0296                     /* store sequence */
0297                     size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
0298                     U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff;  /* swap offset_2 <=> offset_1 */
0299                     hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
0300                     hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
0301                     ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, rLength-MINMATCH);
0302                     ip += rLength;
0303                     anchor = ip;
0304                     continue;   /* faster when present ... (?) */
0305         }   }   }
0306     }   /* while (ip < ilimit) */
0307 
0308     /* save reps for next block */
0309     rep[0] = offset_1 ? offset_1 : offsetSaved;
0310     rep[1] = offset_2 ? offset_2 : offsetSaved;
0311 
0312     /* Return the last literals size */
0313     return (size_t)(iend - anchor);
0314 }
0315 
0316 
0317 size_t ZSTD_compressBlock_doubleFast(
0318         ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
0319         void const* src, size_t srcSize)
0320 {
0321     const U32 mls = ms->cParams.minMatch;
0322     switch(mls)
0323     {
0324     default: /* includes case 3 */
0325     case 4 :
0326         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_noDict);
0327     case 5 :
0328         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_noDict);
0329     case 6 :
0330         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_noDict);
0331     case 7 :
0332         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_noDict);
0333     }
0334 }
0335 
0336 
0337 size_t ZSTD_compressBlock_doubleFast_dictMatchState(
0338         ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
0339         void const* src, size_t srcSize)
0340 {
0341     const U32 mls = ms->cParams.minMatch;
0342     switch(mls)
0343     {
0344     default: /* includes case 3 */
0345     case 4 :
0346         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_dictMatchState);
0347     case 5 :
0348         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_dictMatchState);
0349     case 6 :
0350         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_dictMatchState);
0351     case 7 :
0352         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_dictMatchState);
0353     }
0354 }
0355 
0356 
0357 static size_t ZSTD_compressBlock_doubleFast_extDict_generic(
0358         ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
0359         void const* src, size_t srcSize,
0360         U32 const mls /* template */)
0361 {
0362     ZSTD_compressionParameters const* cParams = &ms->cParams;
0363     U32* const hashLong = ms->hashTable;
0364     U32  const hBitsL = cParams->hashLog;
0365     U32* const hashSmall = ms->chainTable;
0366     U32  const hBitsS = cParams->chainLog;
0367     const BYTE* const istart = (const BYTE*)src;
0368     const BYTE* ip = istart;
0369     const BYTE* anchor = istart;
0370     const BYTE* const iend = istart + srcSize;
0371     const BYTE* const ilimit = iend - 8;
0372     const BYTE* const base = ms->window.base;
0373     const U32   endIndex = (U32)((size_t)(istart - base) + srcSize);
0374     const U32   lowLimit = ZSTD_getLowestMatchIndex(ms, endIndex, cParams->windowLog);
0375     const U32   dictStartIndex = lowLimit;
0376     const U32   dictLimit = ms->window.dictLimit;
0377     const U32   prefixStartIndex = (dictLimit > lowLimit) ? dictLimit : lowLimit;
0378     const BYTE* const prefixStart = base + prefixStartIndex;
0379     const BYTE* const dictBase = ms->window.dictBase;
0380     const BYTE* const dictStart = dictBase + dictStartIndex;
0381     const BYTE* const dictEnd = dictBase + prefixStartIndex;
0382     U32 offset_1=rep[0], offset_2=rep[1];
0383 
0384     DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_extDict_generic (srcSize=%zu)", srcSize);
0385 
0386     /* if extDict is invalidated due to maxDistance, switch to "regular" variant */
0387     if (prefixStartIndex == dictStartIndex)
0388         return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, mls, ZSTD_noDict);
0389 
0390     /* Search Loop */
0391     while (ip < ilimit) {  /* < instead of <=, because (ip+1) */
0392         const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
0393         const U32 matchIndex = hashSmall[hSmall];
0394         const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base;
0395         const BYTE* match = matchBase + matchIndex;
0396 
0397         const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
0398         const U32 matchLongIndex = hashLong[hLong];
0399         const BYTE* const matchLongBase = matchLongIndex < prefixStartIndex ? dictBase : base;
0400         const BYTE* matchLong = matchLongBase + matchLongIndex;
0401 
0402         const U32 curr = (U32)(ip-base);
0403         const U32 repIndex = curr + 1 - offset_1;   /* offset_1 expected <= curr +1 */
0404         const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base;
0405         const BYTE* const repMatch = repBase + repIndex;
0406         size_t mLength;
0407         hashSmall[hSmall] = hashLong[hLong] = curr;   /* update hash table */
0408 
0409         if ((((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex doesn't overlap dict + prefix */
0410             & (repIndex > dictStartIndex))
0411           && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
0412             const BYTE* repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
0413             mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
0414             ip++;
0415             ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
0416         } else {
0417             if ((matchLongIndex > dictStartIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) {
0418                 const BYTE* const matchEnd = matchLongIndex < prefixStartIndex ? dictEnd : iend;
0419                 const BYTE* const lowMatchPtr = matchLongIndex < prefixStartIndex ? dictStart : prefixStart;
0420                 U32 offset;
0421                 mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, prefixStart) + 8;
0422                 offset = curr - matchLongIndex;
0423                 while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; }   /* catch up */
0424                 offset_2 = offset_1;
0425                 offset_1 = offset;
0426                 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
0427 
0428             } else if ((matchIndex > dictStartIndex) && (MEM_read32(match) == MEM_read32(ip))) {
0429                 size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
0430                 U32 const matchIndex3 = hashLong[h3];
0431                 const BYTE* const match3Base = matchIndex3 < prefixStartIndex ? dictBase : base;
0432                 const BYTE* match3 = match3Base + matchIndex3;
0433                 U32 offset;
0434                 hashLong[h3] = curr + 1;
0435                 if ( (matchIndex3 > dictStartIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
0436                     const BYTE* const matchEnd = matchIndex3 < prefixStartIndex ? dictEnd : iend;
0437                     const BYTE* const lowMatchPtr = matchIndex3 < prefixStartIndex ? dictStart : prefixStart;
0438                     mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, prefixStart) + 8;
0439                     ip++;
0440                     offset = curr+1 - matchIndex3;
0441                     while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
0442                 } else {
0443                     const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend;
0444                     const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart;
0445                     mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4;
0446                     offset = curr - matchIndex;
0447                     while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; }   /* catch up */
0448                 }
0449                 offset_2 = offset_1;
0450                 offset_1 = offset;
0451                 ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
0452 
0453             } else {
0454                 ip += ((ip-anchor) >> kSearchStrength) + 1;
0455                 continue;
0456         }   }
0457 
0458         /* move to next sequence start */
0459         ip += mLength;
0460         anchor = ip;
0461 
0462         if (ip <= ilimit) {
0463             /* Complementary insertion */
0464             /* done after iLimit test, as candidates could be > iend-8 */
0465             {   U32 const indexToInsert = curr+2;
0466                 hashLong[ZSTD_hashPtr(base+indexToInsert, hBitsL, 8)] = indexToInsert;
0467                 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
0468                 hashSmall[ZSTD_hashPtr(base+indexToInsert, hBitsS, mls)] = indexToInsert;
0469                 hashSmall[ZSTD_hashPtr(ip-1, hBitsS, mls)] = (U32)(ip-1-base);
0470             }
0471 
0472             /* check immediate repcode */
0473             while (ip <= ilimit) {
0474                 U32 const current2 = (U32)(ip-base);
0475                 U32 const repIndex2 = current2 - offset_2;
0476                 const BYTE* repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
0477                 if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3)   /* intentional overflow : ensure repIndex2 doesn't overlap dict + prefix */
0478                     & (repIndex2 > dictStartIndex))
0479                   && (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
0480                     const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
0481                     size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
0482                     U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset;   /* swap offset_2 <=> offset_1 */
0483                     ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
0484                     hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
0485                     hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
0486                     ip += repLength2;
0487                     anchor = ip;
0488                     continue;
0489                 }
0490                 break;
0491     }   }   }
0492 
0493     /* save reps for next block */
0494     rep[0] = offset_1;
0495     rep[1] = offset_2;
0496 
0497     /* Return the last literals size */
0498     return (size_t)(iend - anchor);
0499 }
0500 
0501 
0502 size_t ZSTD_compressBlock_doubleFast_extDict(
0503         ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
0504         void const* src, size_t srcSize)
0505 {
0506     U32 const mls = ms->cParams.minMatch;
0507     switch(mls)
0508     {
0509     default: /* includes case 3 */
0510     case 4 :
0511         return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 4);
0512     case 5 :
0513         return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 5);
0514     case 6 :
0515         return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 6);
0516     case 7 :
0517         return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 7);
0518     }
0519 }
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