1 /* 2 * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 #include "zstd_compress_internal.h" 12 #include "zstd_lazy.h" 13 14 15 /*-************************************* 16 * Binary Tree search 17 ***************************************/ 18 19 static void 20 ZSTD_updateDUBT(ZSTD_matchState_t* ms, 21 const BYTE* ip, const BYTE* iend, 22 U32 mls) 23 { 24 const ZSTD_compressionParameters* const cParams = &ms->cParams; 25 U32* const hashTable = ms->hashTable; 26 U32 const hashLog = cParams->hashLog; 27 28 U32* const bt = ms->chainTable; 29 U32 const btLog = cParams->chainLog - 1; 30 U32 const btMask = (1 << btLog) - 1; 31 32 const BYTE* const base = ms->window.base; 33 U32 const target = (U32)(ip - base); 34 U32 idx = ms->nextToUpdate; 35 36 if (idx != target) 37 DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)", 38 idx, target, ms->window.dictLimit); 39 assert(ip + 8 <= iend); /* condition for ZSTD_hashPtr */ 40 (void)iend; 41 42 assert(idx >= ms->window.dictLimit); /* condition for valid base+idx */ 43 for ( ; idx < target ; idx++) { 44 size_t const h = ZSTD_hashPtr(base + idx, hashLog, mls); /* assumption : ip + 8 <= iend */ 45 U32 const matchIndex = hashTable[h]; 46 47 U32* const nextCandidatePtr = bt + 2*(idx&btMask); 48 U32* const sortMarkPtr = nextCandidatePtr + 1; 49 50 DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx); 51 hashTable[h] = idx; /* Update Hash Table */ 52 *nextCandidatePtr = matchIndex; /* update BT like a chain */ 53 *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK; 54 } 55 ms->nextToUpdate = target; 56 } 57 58 59 /** ZSTD_insertDUBT1() : 60 * sort one already inserted but unsorted position 61 * assumption : curr >= btlow == (curr - btmask) 62 * doesn't fail */ 63 static void 64 ZSTD_insertDUBT1(ZSTD_matchState_t* ms, 65 U32 curr, const BYTE* inputEnd, 66 U32 nbCompares, U32 btLow, 67 const ZSTD_dictMode_e dictMode) 68 { 69 const ZSTD_compressionParameters* const cParams = &ms->cParams; 70 U32* const bt = ms->chainTable; 71 U32 const btLog = cParams->chainLog - 1; 72 U32 const btMask = (1 << btLog) - 1; 73 size_t commonLengthSmaller=0, commonLengthLarger=0; 74 const BYTE* const base = ms->window.base; 75 const BYTE* const dictBase = ms->window.dictBase; 76 const U32 dictLimit = ms->window.dictLimit; 77 const BYTE* const ip = (curr>=dictLimit) ? base + curr : dictBase + curr; 78 const BYTE* const iend = (curr>=dictLimit) ? inputEnd : dictBase + dictLimit; 79 const BYTE* const dictEnd = dictBase + dictLimit; 80 const BYTE* const prefixStart = base + dictLimit; 81 const BYTE* match; 82 U32* smallerPtr = bt + 2*(curr&btMask); 83 U32* largerPtr = smallerPtr + 1; 84 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) */ 85 U32 dummy32; /* to be nullified at the end */ 86 U32 const windowValid = ms->window.lowLimit; 87 U32 const maxDistance = 1U << cParams->windowLog; 88 U32 const windowLow = (curr - windowValid > maxDistance) ? curr - maxDistance : windowValid; 89 90 91 DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)", 92 curr, dictLimit, windowLow); 93 assert(curr >= btLow); 94 assert(ip < iend); /* condition for ZSTD_count */ 95 96 while (nbCompares-- && (matchIndex > windowLow)) { 97 U32* const nextPtr = bt + 2*(matchIndex & btMask); 98 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ 99 assert(matchIndex < curr); 100 /* note : all candidates are now supposed sorted, 101 * but it's still possible to have nextPtr[1] == ZSTD_DUBT_UNSORTED_MARK 102 * when a real index has the same value as ZSTD_DUBT_UNSORTED_MARK */ 103 104 if ( (dictMode != ZSTD_extDict) 105 || (matchIndex+matchLength >= dictLimit) /* both in current segment*/ 106 || (curr < dictLimit) /* both in extDict */) { 107 const BYTE* const mBase = ( (dictMode != ZSTD_extDict) 108 || (matchIndex+matchLength >= dictLimit)) ? 109 base : dictBase; 110 assert( (matchIndex+matchLength >= dictLimit) /* might be wrong if extDict is incorrectly set to 0 */ 111 || (curr < dictLimit) ); 112 match = mBase + matchIndex; 113 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend); 114 } else { 115 match = dictBase + matchIndex; 116 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart); 117 if (matchIndex+matchLength >= dictLimit) 118 match = base + matchIndex; /* preparation for next read of match[matchLength] */ 119 } 120 121 DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ", 122 curr, matchIndex, (U32)matchLength); 123 124 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */ 125 break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */ 126 } 127 128 if (match[matchLength] < ip[matchLength]) { /* necessarily within buffer */ 129 /* match is smaller than current */ 130 *smallerPtr = matchIndex; /* update smaller idx */ 131 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */ 132 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop searching */ 133 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u", 134 matchIndex, btLow, nextPtr[1]); 135 smallerPtr = nextPtr+1; /* new "candidate" => larger than match, which was smaller than target */ 136 matchIndex = nextPtr[1]; /* new matchIndex, larger than previous and closer to current */ 137 } else { 138 /* match is larger than current */ 139 *largerPtr = matchIndex; 140 commonLengthLarger = matchLength; 141 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop searching */ 142 DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u", 143 matchIndex, btLow, nextPtr[0]); 144 largerPtr = nextPtr; 145 matchIndex = nextPtr[0]; 146 } } 147 148 *smallerPtr = *largerPtr = 0; 149 } 150 151 152 static size_t 153 ZSTD_DUBT_findBetterDictMatch ( 154 ZSTD_matchState_t* ms, 155 const BYTE* const ip, const BYTE* const iend, 156 size_t* offsetPtr, 157 size_t bestLength, 158 U32 nbCompares, 159 U32 const mls, 160 const ZSTD_dictMode_e dictMode) 161 { 162 const ZSTD_matchState_t * const dms = ms->dictMatchState; 163 const ZSTD_compressionParameters* const dmsCParams = &dms->cParams; 164 const U32 * const dictHashTable = dms->hashTable; 165 U32 const hashLog = dmsCParams->hashLog; 166 size_t const h = ZSTD_hashPtr(ip, hashLog, mls); 167 U32 dictMatchIndex = dictHashTable[h]; 168 169 const BYTE* const base = ms->window.base; 170 const BYTE* const prefixStart = base + ms->window.dictLimit; 171 U32 const curr = (U32)(ip-base); 172 const BYTE* const dictBase = dms->window.base; 173 const BYTE* const dictEnd = dms->window.nextSrc; 174 U32 const dictHighLimit = (U32)(dms->window.nextSrc - dms->window.base); 175 U32 const dictLowLimit = dms->window.lowLimit; 176 U32 const dictIndexDelta = ms->window.lowLimit - dictHighLimit; 177 178 U32* const dictBt = dms->chainTable; 179 U32 const btLog = dmsCParams->chainLog - 1; 180 U32 const btMask = (1 << btLog) - 1; 181 U32 const btLow = (btMask >= dictHighLimit - dictLowLimit) ? dictLowLimit : dictHighLimit - btMask; 182 183 size_t commonLengthSmaller=0, commonLengthLarger=0; 184 185 (void)dictMode; 186 assert(dictMode == ZSTD_dictMatchState); 187 188 while (nbCompares-- && (dictMatchIndex > dictLowLimit)) { 189 U32* const nextPtr = dictBt + 2*(dictMatchIndex & btMask); 190 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ 191 const BYTE* match = dictBase + dictMatchIndex; 192 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart); 193 if (dictMatchIndex+matchLength >= dictHighLimit) 194 match = base + dictMatchIndex + dictIndexDelta; /* to prepare for next usage of match[matchLength] */ 195 196 if (matchLength > bestLength) { 197 U32 matchIndex = dictMatchIndex + dictIndexDelta; 198 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(curr-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) { 199 DEBUGLOG(9, "ZSTD_DUBT_findBetterDictMatch(%u) : found better match length %u -> %u and offsetCode %u -> %u (dictMatchIndex %u, matchIndex %u)", 200 curr, (U32)bestLength, (U32)matchLength, (U32)*offsetPtr, ZSTD_REP_MOVE + curr - matchIndex, dictMatchIndex, matchIndex); 201 bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + curr - matchIndex; 202 } 203 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 */ 204 break; /* drop, to guarantee consistency (miss a little bit of compression) */ 205 } 206 } 207 208 if (match[matchLength] < ip[matchLength]) { 209 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */ 210 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */ 211 dictMatchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */ 212 } else { 213 /* match is larger than current */ 214 if (dictMatchIndex <= btLow) { break; } /* beyond tree size, stop the search */ 215 commonLengthLarger = matchLength; 216 dictMatchIndex = nextPtr[0]; 217 } 218 } 219 220 if (bestLength >= MINMATCH) { 221 U32 const mIndex = curr - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex; 222 DEBUGLOG(8, "ZSTD_DUBT_findBetterDictMatch(%u) : found match of length %u and offsetCode %u (pos %u)", 223 curr, (U32)bestLength, (U32)*offsetPtr, mIndex); 224 } 225 return bestLength; 226 227 } 228 229 230 static size_t 231 ZSTD_DUBT_findBestMatch(ZSTD_matchState_t* ms, 232 const BYTE* const ip, const BYTE* const iend, 233 size_t* offsetPtr, 234 U32 const mls, 235 const ZSTD_dictMode_e dictMode) 236 { 237 const ZSTD_compressionParameters* const cParams = &ms->cParams; 238 U32* const hashTable = ms->hashTable; 239 U32 const hashLog = cParams->hashLog; 240 size_t const h = ZSTD_hashPtr(ip, hashLog, mls); 241 U32 matchIndex = hashTable[h]; 242 243 const BYTE* const base = ms->window.base; 244 U32 const curr = (U32)(ip-base); 245 U32 const windowLow = ZSTD_getLowestMatchIndex(ms, curr, cParams->windowLog); 246 247 U32* const bt = ms->chainTable; 248 U32 const btLog = cParams->chainLog - 1; 249 U32 const btMask = (1 << btLog) - 1; 250 U32 const btLow = (btMask >= curr) ? 0 : curr - btMask; 251 U32 const unsortLimit = MAX(btLow, windowLow); 252 253 U32* nextCandidate = bt + 2*(matchIndex&btMask); 254 U32* unsortedMark = bt + 2*(matchIndex&btMask) + 1; 255 U32 nbCompares = 1U << cParams->searchLog; 256 U32 nbCandidates = nbCompares; 257 U32 previousCandidate = 0; 258 259 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", curr); 260 assert(ip <= iend-8); /* required for h calculation */ 261 assert(dictMode != ZSTD_dedicatedDictSearch); 262 263 /* reach end of unsorted candidates list */ 264 while ( (matchIndex > unsortLimit) 265 && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK) 266 && (nbCandidates > 1) ) { 267 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted", 268 matchIndex); 269 *unsortedMark = previousCandidate; /* the unsortedMark becomes a reversed chain, to move up back to original position */ 270 previousCandidate = matchIndex; 271 matchIndex = *nextCandidate; 272 nextCandidate = bt + 2*(matchIndex&btMask); 273 unsortedMark = bt + 2*(matchIndex&btMask) + 1; 274 nbCandidates --; 275 } 276 277 /* nullify last candidate if it's still unsorted 278 * simplification, detrimental to compression ratio, beneficial for speed */ 279 if ( (matchIndex > unsortLimit) 280 && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) { 281 DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u", 282 matchIndex); 283 *nextCandidate = *unsortedMark = 0; 284 } 285 286 /* batch sort stacked candidates */ 287 matchIndex = previousCandidate; 288 while (matchIndex) { /* will end on matchIndex == 0 */ 289 U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1; 290 U32 const nextCandidateIdx = *nextCandidateIdxPtr; 291 ZSTD_insertDUBT1(ms, matchIndex, iend, 292 nbCandidates, unsortLimit, dictMode); 293 matchIndex = nextCandidateIdx; 294 nbCandidates++; 295 } 296 297 /* find longest match */ 298 { size_t commonLengthSmaller = 0, commonLengthLarger = 0; 299 const BYTE* const dictBase = ms->window.dictBase; 300 const U32 dictLimit = ms->window.dictLimit; 301 const BYTE* const dictEnd = dictBase + dictLimit; 302 const BYTE* const prefixStart = base + dictLimit; 303 U32* smallerPtr = bt + 2*(curr&btMask); 304 U32* largerPtr = bt + 2*(curr&btMask) + 1; 305 U32 matchEndIdx = curr + 8 + 1; 306 U32 dummy32; /* to be nullified at the end */ 307 size_t bestLength = 0; 308 309 matchIndex = hashTable[h]; 310 hashTable[h] = curr; /* Update Hash Table */ 311 312 while (nbCompares-- && (matchIndex > windowLow)) { 313 U32* const nextPtr = bt + 2*(matchIndex & btMask); 314 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ 315 const BYTE* match; 316 317 if ((dictMode != ZSTD_extDict) || (matchIndex+matchLength >= dictLimit)) { 318 match = base + matchIndex; 319 matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend); 320 } else { 321 match = dictBase + matchIndex; 322 matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart); 323 if (matchIndex+matchLength >= dictLimit) 324 match = base + matchIndex; /* to prepare for next usage of match[matchLength] */ 325 } 326 327 if (matchLength > bestLength) { 328 if (matchLength > matchEndIdx - matchIndex) 329 matchEndIdx = matchIndex + (U32)matchLength; 330 if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(curr-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) ) 331 bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + curr - matchIndex; 332 if (ip+matchLength == iend) { /* equal : no way to know if inf or sup */ 333 if (dictMode == ZSTD_dictMatchState) { 334 nbCompares = 0; /* in addition to avoiding checking any 335 * further in this loop, make sure we 336 * skip checking in the dictionary. */ 337 } 338 break; /* drop, to guarantee consistency (miss a little bit of compression) */ 339 } 340 } 341 342 if (match[matchLength] < ip[matchLength]) { 343 /* match is smaller than current */ 344 *smallerPtr = matchIndex; /* update smaller idx */ 345 commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */ 346 if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */ 347 smallerPtr = nextPtr+1; /* new "smaller" => larger of match */ 348 matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */ 349 } else { 350 /* match is larger than current */ 351 *largerPtr = matchIndex; 352 commonLengthLarger = matchLength; 353 if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */ 354 largerPtr = nextPtr; 355 matchIndex = nextPtr[0]; 356 } } 357 358 *smallerPtr = *largerPtr = 0; 359 360 if (dictMode == ZSTD_dictMatchState && nbCompares) { 361 bestLength = ZSTD_DUBT_findBetterDictMatch( 362 ms, ip, iend, 363 offsetPtr, bestLength, nbCompares, 364 mls, dictMode); 365 } 366 367 assert(matchEndIdx > curr+8); /* ensure nextToUpdate is increased */ 368 ms->nextToUpdate = matchEndIdx - 8; /* skip repetitive patterns */ 369 if (bestLength >= MINMATCH) { 370 U32 const mIndex = curr - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex; 371 DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)", 372 curr, (U32)bestLength, (U32)*offsetPtr, mIndex); 373 } 374 return bestLength; 375 } 376 } 377 378 379 /** ZSTD_BtFindBestMatch() : Tree updater, providing best match */ 380 FORCE_INLINE_TEMPLATE size_t 381 ZSTD_BtFindBestMatch( ZSTD_matchState_t* ms, 382 const BYTE* const ip, const BYTE* const iLimit, 383 size_t* offsetPtr, 384 const U32 mls /* template */, 385 const ZSTD_dictMode_e dictMode) 386 { 387 DEBUGLOG(7, "ZSTD_BtFindBestMatch"); 388 if (ip < ms->window.base + ms->nextToUpdate) return 0; /* skipped area */ 389 ZSTD_updateDUBT(ms, ip, iLimit, mls); 390 return ZSTD_DUBT_findBestMatch(ms, ip, iLimit, offsetPtr, mls, dictMode); 391 } 392 393 394 static size_t 395 ZSTD_BtFindBestMatch_selectMLS ( ZSTD_matchState_t* ms, 396 const BYTE* ip, const BYTE* const iLimit, 397 size_t* offsetPtr) 398 { 399 switch(ms->cParams.minMatch) 400 { 401 default : /* includes case 3 */ 402 case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict); 403 case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict); 404 case 7 : 405 case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict); 406 } 407 } 408 409 410 static size_t ZSTD_BtFindBestMatch_dictMatchState_selectMLS ( 411 ZSTD_matchState_t* ms, 412 const BYTE* ip, const BYTE* const iLimit, 413 size_t* offsetPtr) 414 { 415 switch(ms->cParams.minMatch) 416 { 417 default : /* includes case 3 */ 418 case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState); 419 case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState); 420 case 7 : 421 case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState); 422 } 423 } 424 425 426 static size_t ZSTD_BtFindBestMatch_extDict_selectMLS ( 427 ZSTD_matchState_t* ms, 428 const BYTE* ip, const BYTE* const iLimit, 429 size_t* offsetPtr) 430 { 431 switch(ms->cParams.minMatch) 432 { 433 default : /* includes case 3 */ 434 case 4 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict); 435 case 5 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict); 436 case 7 : 437 case 6 : return ZSTD_BtFindBestMatch(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict); 438 } 439 } 440 441 442 443 /* ********************************* 444 * Hash Chain 445 ***********************************/ 446 #define NEXT_IN_CHAIN(d, mask) chainTable[(d) & (mask)] 447 448 /* Update chains up to ip (excluded) 449 Assumption : always within prefix (i.e. not within extDict) */ 450 FORCE_INLINE_TEMPLATE U32 ZSTD_insertAndFindFirstIndex_internal( 451 ZSTD_matchState_t* ms, 452 const ZSTD_compressionParameters* const cParams, 453 const BYTE* ip, U32 const mls) 454 { 455 U32* const hashTable = ms->hashTable; 456 const U32 hashLog = cParams->hashLog; 457 U32* const chainTable = ms->chainTable; 458 const U32 chainMask = (1 << cParams->chainLog) - 1; 459 const BYTE* const base = ms->window.base; 460 const U32 target = (U32)(ip - base); 461 U32 idx = ms->nextToUpdate; 462 463 while(idx < target) { /* catch up */ 464 size_t const h = ZSTD_hashPtr(base+idx, hashLog, mls); 465 NEXT_IN_CHAIN(idx, chainMask) = hashTable[h]; 466 hashTable[h] = idx; 467 idx++; 468 } 469 470 ms->nextToUpdate = target; 471 return hashTable[ZSTD_hashPtr(ip, hashLog, mls)]; 472 } 473 474 U32 ZSTD_insertAndFindFirstIndex(ZSTD_matchState_t* ms, const BYTE* ip) { 475 const ZSTD_compressionParameters* const cParams = &ms->cParams; 476 return ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, ms->cParams.minMatch); 477 } 478 479 void ZSTD_dedicatedDictSearch_lazy_loadDictionary(ZSTD_matchState_t* ms, const BYTE* const ip) 480 { 481 const BYTE* const base = ms->window.base; 482 U32 const target = (U32)(ip - base); 483 U32* const hashTable = ms->hashTable; 484 U32* const chainTable = ms->chainTable; 485 U32 const chainSize = 1 << ms->cParams.chainLog; 486 U32 idx = ms->nextToUpdate; 487 U32 const minChain = chainSize < target ? target - chainSize : idx; 488 U32 const bucketSize = 1 << ZSTD_LAZY_DDSS_BUCKET_LOG; 489 U32 const cacheSize = bucketSize - 1; 490 U32 const chainAttempts = (1 << ms->cParams.searchLog) - cacheSize; 491 U32 const chainLimit = chainAttempts > 255 ? 255 : chainAttempts; 492 493 /* We know the hashtable is oversized by a factor of `bucketSize`. 494 * We are going to temporarily pretend `bucketSize == 1`, keeping only a 495 * single entry. We will use the rest of the space to construct a temporary 496 * chaintable. 497 */ 498 U32 const hashLog = ms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG; 499 U32* const tmpHashTable = hashTable; 500 U32* const tmpChainTable = hashTable + ((size_t)1 << hashLog); 501 U32 const tmpChainSize = ((1 << ZSTD_LAZY_DDSS_BUCKET_LOG) - 1) << hashLog; 502 U32 const tmpMinChain = tmpChainSize < target ? target - tmpChainSize : idx; 503 504 U32 hashIdx; 505 506 assert(ms->cParams.chainLog <= 24); 507 assert(ms->cParams.hashLog >= ms->cParams.chainLog); 508 assert(idx != 0); 509 assert(tmpMinChain <= minChain); 510 511 /* fill conventional hash table and conventional chain table */ 512 for ( ; idx < target; idx++) { 513 U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch); 514 if (idx >= tmpMinChain) { 515 tmpChainTable[idx - tmpMinChain] = hashTable[h]; 516 } 517 tmpHashTable[h] = idx; 518 } 519 520 /* sort chains into ddss chain table */ 521 { 522 U32 chainPos = 0; 523 for (hashIdx = 0; hashIdx < (1U << hashLog); hashIdx++) { 524 U32 count; 525 U32 countBeyondMinChain = 0; 526 U32 i = tmpHashTable[hashIdx]; 527 for (count = 0; i >= tmpMinChain && count < cacheSize; count++) { 528 /* skip through the chain to the first position that won't be 529 * in the hash cache bucket */ 530 if (i < minChain) { 531 countBeyondMinChain++; 532 } 533 i = tmpChainTable[i - tmpMinChain]; 534 } 535 if (count == cacheSize) { 536 for (count = 0; count < chainLimit;) { 537 if (i < minChain) { 538 if (!i || countBeyondMinChain++ > cacheSize) { 539 /* only allow pulling `cacheSize` number of entries 540 * into the cache or chainTable beyond `minChain`, 541 * to replace the entries pulled out of the 542 * chainTable into the cache. This lets us reach 543 * back further without increasing the total number 544 * of entries in the chainTable, guaranteeing the 545 * DDSS chain table will fit into the space 546 * allocated for the regular one. */ 547 break; 548 } 549 } 550 chainTable[chainPos++] = i; 551 count++; 552 if (i < tmpMinChain) { 553 break; 554 } 555 i = tmpChainTable[i - tmpMinChain]; 556 } 557 } else { 558 count = 0; 559 } 560 if (count) { 561 tmpHashTable[hashIdx] = ((chainPos - count) << 8) + count; 562 } else { 563 tmpHashTable[hashIdx] = 0; 564 } 565 } 566 assert(chainPos <= chainSize); /* I believe this is guaranteed... */ 567 } 568 569 /* move chain pointers into the last entry of each hash bucket */ 570 for (hashIdx = (1 << hashLog); hashIdx; ) { 571 U32 const bucketIdx = --hashIdx << ZSTD_LAZY_DDSS_BUCKET_LOG; 572 U32 const chainPackedPointer = tmpHashTable[hashIdx]; 573 U32 i; 574 for (i = 0; i < cacheSize; i++) { 575 hashTable[bucketIdx + i] = 0; 576 } 577 hashTable[bucketIdx + bucketSize - 1] = chainPackedPointer; 578 } 579 580 /* fill the buckets of the hash table */ 581 for (idx = ms->nextToUpdate; idx < target; idx++) { 582 U32 const h = (U32)ZSTD_hashPtr(base + idx, hashLog, ms->cParams.minMatch) 583 << ZSTD_LAZY_DDSS_BUCKET_LOG; 584 U32 i; 585 /* Shift hash cache down 1. */ 586 for (i = cacheSize - 1; i; i--) 587 hashTable[h + i] = hashTable[h + i - 1]; 588 hashTable[h] = idx; 589 } 590 591 ms->nextToUpdate = target; 592 } 593 594 595 /* inlining is important to hardwire a hot branch (template emulation) */ 596 FORCE_INLINE_TEMPLATE 597 size_t ZSTD_HcFindBestMatch_generic ( 598 ZSTD_matchState_t* ms, 599 const BYTE* const ip, const BYTE* const iLimit, 600 size_t* offsetPtr, 601 const U32 mls, const ZSTD_dictMode_e dictMode) 602 { 603 const ZSTD_compressionParameters* const cParams = &ms->cParams; 604 U32* const chainTable = ms->chainTable; 605 const U32 chainSize = (1 << cParams->chainLog); 606 const U32 chainMask = chainSize-1; 607 const BYTE* const base = ms->window.base; 608 const BYTE* const dictBase = ms->window.dictBase; 609 const U32 dictLimit = ms->window.dictLimit; 610 const BYTE* const prefixStart = base + dictLimit; 611 const BYTE* const dictEnd = dictBase + dictLimit; 612 const U32 curr = (U32)(ip-base); 613 const U32 maxDistance = 1U << cParams->windowLog; 614 const U32 lowestValid = ms->window.lowLimit; 615 const U32 withinMaxDistance = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid; 616 const U32 isDictionary = (ms->loadedDictEnd != 0); 617 const U32 lowLimit = isDictionary ? lowestValid : withinMaxDistance; 618 const U32 minChain = curr > chainSize ? curr - chainSize : 0; 619 U32 nbAttempts = 1U << cParams->searchLog; 620 size_t ml=4-1; 621 622 const ZSTD_matchState_t* const dms = ms->dictMatchState; 623 const U32 ddsHashLog = dictMode == ZSTD_dedicatedDictSearch 624 ? dms->cParams.hashLog - ZSTD_LAZY_DDSS_BUCKET_LOG : 0; 625 const size_t ddsIdx = dictMode == ZSTD_dedicatedDictSearch 626 ? ZSTD_hashPtr(ip, ddsHashLog, mls) << ZSTD_LAZY_DDSS_BUCKET_LOG : 0; 627 628 U32 matchIndex; 629 630 if (dictMode == ZSTD_dedicatedDictSearch) { 631 const U32* entry = &dms->hashTable[ddsIdx]; 632 PREFETCH_L1(entry); 633 } 634 635 /* HC4 match finder */ 636 matchIndex = ZSTD_insertAndFindFirstIndex_internal(ms, cParams, ip, mls); 637 638 for ( ; (matchIndex>=lowLimit) & (nbAttempts>0) ; nbAttempts--) { 639 size_t currentMl=0; 640 if ((dictMode != ZSTD_extDict) || matchIndex >= dictLimit) { 641 const BYTE* const match = base + matchIndex; 642 assert(matchIndex >= dictLimit); /* ensures this is true if dictMode != ZSTD_extDict */ 643 if (match[ml] == ip[ml]) /* potentially better */ 644 currentMl = ZSTD_count(ip, match, iLimit); 645 } else { 646 const BYTE* const match = dictBase + matchIndex; 647 assert(match+4 <= dictEnd); 648 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */ 649 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dictEnd, prefixStart) + 4; 650 } 651 652 /* save best solution */ 653 if (currentMl > ml) { 654 ml = currentMl; 655 *offsetPtr = curr - matchIndex + ZSTD_REP_MOVE; 656 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */ 657 } 658 659 if (matchIndex <= minChain) break; 660 matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask); 661 } 662 663 if (dictMode == ZSTD_dedicatedDictSearch) { 664 const U32 ddsLowestIndex = dms->window.dictLimit; 665 const BYTE* const ddsBase = dms->window.base; 666 const BYTE* const ddsEnd = dms->window.nextSrc; 667 const U32 ddsSize = (U32)(ddsEnd - ddsBase); 668 const U32 ddsIndexDelta = dictLimit - ddsSize; 669 const U32 bucketSize = (1 << ZSTD_LAZY_DDSS_BUCKET_LOG); 670 const U32 bucketLimit = nbAttempts < bucketSize - 1 ? nbAttempts : bucketSize - 1; 671 U32 ddsAttempt; 672 673 for (ddsAttempt = 0; ddsAttempt < bucketSize - 1; ddsAttempt++) { 674 PREFETCH_L1(ddsBase + dms->hashTable[ddsIdx + ddsAttempt]); 675 } 676 677 { 678 U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1]; 679 U32 const chainIndex = chainPackedPointer >> 8; 680 681 PREFETCH_L1(&dms->chainTable[chainIndex]); 682 } 683 684 for (ddsAttempt = 0; ddsAttempt < bucketLimit; ddsAttempt++) { 685 size_t currentMl=0; 686 const BYTE* match; 687 matchIndex = dms->hashTable[ddsIdx + ddsAttempt]; 688 match = ddsBase + matchIndex; 689 690 if (!matchIndex) { 691 return ml; 692 } 693 694 /* guaranteed by table construction */ 695 (void)ddsLowestIndex; 696 assert(matchIndex >= ddsLowestIndex); 697 assert(match+4 <= ddsEnd); 698 if (MEM_read32(match) == MEM_read32(ip)) { 699 /* assumption : matchIndex <= dictLimit-4 (by table construction) */ 700 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4; 701 } 702 703 /* save best solution */ 704 if (currentMl > ml) { 705 ml = currentMl; 706 *offsetPtr = curr - (matchIndex + ddsIndexDelta) + ZSTD_REP_MOVE; 707 if (ip+currentMl == iLimit) { 708 /* best possible, avoids read overflow on next attempt */ 709 return ml; 710 } 711 } 712 } 713 714 { 715 U32 const chainPackedPointer = dms->hashTable[ddsIdx + bucketSize - 1]; 716 U32 chainIndex = chainPackedPointer >> 8; 717 U32 const chainLength = chainPackedPointer & 0xFF; 718 U32 const chainAttempts = nbAttempts - ddsAttempt; 719 U32 const chainLimit = chainAttempts > chainLength ? chainLength : chainAttempts; 720 U32 chainAttempt; 721 722 for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++) { 723 PREFETCH_L1(ddsBase + dms->chainTable[chainIndex + chainAttempt]); 724 } 725 726 for (chainAttempt = 0 ; chainAttempt < chainLimit; chainAttempt++, chainIndex++) { 727 size_t currentMl=0; 728 const BYTE* match; 729 matchIndex = dms->chainTable[chainIndex]; 730 match = ddsBase + matchIndex; 731 732 /* guaranteed by table construction */ 733 assert(matchIndex >= ddsLowestIndex); 734 assert(match+4 <= ddsEnd); 735 if (MEM_read32(match) == MEM_read32(ip)) { 736 /* assumption : matchIndex <= dictLimit-4 (by table construction) */ 737 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, ddsEnd, prefixStart) + 4; 738 } 739 740 /* save best solution */ 741 if (currentMl > ml) { 742 ml = currentMl; 743 *offsetPtr = curr - (matchIndex + ddsIndexDelta) + ZSTD_REP_MOVE; 744 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */ 745 } 746 } 747 } 748 } else if (dictMode == ZSTD_dictMatchState) { 749 const U32* const dmsChainTable = dms->chainTable; 750 const U32 dmsChainSize = (1 << dms->cParams.chainLog); 751 const U32 dmsChainMask = dmsChainSize - 1; 752 const U32 dmsLowestIndex = dms->window.dictLimit; 753 const BYTE* const dmsBase = dms->window.base; 754 const BYTE* const dmsEnd = dms->window.nextSrc; 755 const U32 dmsSize = (U32)(dmsEnd - dmsBase); 756 const U32 dmsIndexDelta = dictLimit - dmsSize; 757 const U32 dmsMinChain = dmsSize > dmsChainSize ? dmsSize - dmsChainSize : 0; 758 759 matchIndex = dms->hashTable[ZSTD_hashPtr(ip, dms->cParams.hashLog, mls)]; 760 761 for ( ; (matchIndex>=dmsLowestIndex) & (nbAttempts>0) ; nbAttempts--) { 762 size_t currentMl=0; 763 const BYTE* const match = dmsBase + matchIndex; 764 assert(match+4 <= dmsEnd); 765 if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */ 766 currentMl = ZSTD_count_2segments(ip+4, match+4, iLimit, dmsEnd, prefixStart) + 4; 767 768 /* save best solution */ 769 if (currentMl > ml) { 770 ml = currentMl; 771 *offsetPtr = curr - (matchIndex + dmsIndexDelta) + ZSTD_REP_MOVE; 772 if (ip+currentMl == iLimit) break; /* best possible, avoids read overflow on next attempt */ 773 } 774 775 if (matchIndex <= dmsMinChain) break; 776 777 matchIndex = dmsChainTable[matchIndex & dmsChainMask]; 778 } 779 } 780 781 return ml; 782 } 783 784 785 FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_selectMLS ( 786 ZSTD_matchState_t* ms, 787 const BYTE* ip, const BYTE* const iLimit, 788 size_t* offsetPtr) 789 { 790 switch(ms->cParams.minMatch) 791 { 792 default : /* includes case 3 */ 793 case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_noDict); 794 case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_noDict); 795 case 7 : 796 case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_noDict); 797 } 798 } 799 800 801 static size_t ZSTD_HcFindBestMatch_dictMatchState_selectMLS ( 802 ZSTD_matchState_t* ms, 803 const BYTE* ip, const BYTE* const iLimit, 804 size_t* offsetPtr) 805 { 806 switch(ms->cParams.minMatch) 807 { 808 default : /* includes case 3 */ 809 case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_dictMatchState); 810 case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_dictMatchState); 811 case 7 : 812 case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_dictMatchState); 813 } 814 } 815 816 817 static size_t ZSTD_HcFindBestMatch_dedicatedDictSearch_selectMLS ( 818 ZSTD_matchState_t* ms, 819 const BYTE* ip, const BYTE* const iLimit, 820 size_t* offsetPtr) 821 { 822 switch(ms->cParams.minMatch) 823 { 824 default : /* includes case 3 */ 825 case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_dedicatedDictSearch); 826 case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_dedicatedDictSearch); 827 case 7 : 828 case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_dedicatedDictSearch); 829 } 830 } 831 832 833 FORCE_INLINE_TEMPLATE size_t ZSTD_HcFindBestMatch_extDict_selectMLS ( 834 ZSTD_matchState_t* ms, 835 const BYTE* ip, const BYTE* const iLimit, 836 size_t* offsetPtr) 837 { 838 switch(ms->cParams.minMatch) 839 { 840 default : /* includes case 3 */ 841 case 4 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 4, ZSTD_extDict); 842 case 5 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 5, ZSTD_extDict); 843 case 7 : 844 case 6 : return ZSTD_HcFindBestMatch_generic(ms, ip, iLimit, offsetPtr, 6, ZSTD_extDict); 845 } 846 } 847 848 849 /* ******************************* 850 * Common parser - lazy strategy 851 *********************************/ 852 typedef enum { search_hashChain, search_binaryTree } searchMethod_e; 853 854 FORCE_INLINE_TEMPLATE size_t 855 ZSTD_compressBlock_lazy_generic( 856 ZSTD_matchState_t* ms, seqStore_t* seqStore, 857 U32 rep[ZSTD_REP_NUM], 858 const void* src, size_t srcSize, 859 const searchMethod_e searchMethod, const U32 depth, 860 ZSTD_dictMode_e const dictMode) 861 { 862 const BYTE* const istart = (const BYTE*)src; 863 const BYTE* ip = istart; 864 const BYTE* anchor = istart; 865 const BYTE* const iend = istart + srcSize; 866 const BYTE* const ilimit = iend - 8; 867 const BYTE* const base = ms->window.base; 868 const U32 prefixLowestIndex = ms->window.dictLimit; 869 const BYTE* const prefixLowest = base + prefixLowestIndex; 870 871 typedef size_t (*searchMax_f)( 872 ZSTD_matchState_t* ms, 873 const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr); 874 875 /** 876 * This table is indexed first by the four ZSTD_dictMode_e values, and then 877 * by the two searchMethod_e values. NULLs are placed for configurations 878 * that should never occur (extDict modes go to the other implementation 879 * below and there is no DDSS for binary tree search yet). 880 */ 881 const searchMax_f searchFuncs[4][2] = { 882 { 883 ZSTD_HcFindBestMatch_selectMLS, 884 ZSTD_BtFindBestMatch_selectMLS 885 }, 886 { 887 NULL, 888 NULL 889 }, 890 { 891 ZSTD_HcFindBestMatch_dictMatchState_selectMLS, 892 ZSTD_BtFindBestMatch_dictMatchState_selectMLS 893 }, 894 { 895 ZSTD_HcFindBestMatch_dedicatedDictSearch_selectMLS, 896 NULL 897 } 898 }; 899 900 searchMax_f const searchMax = searchFuncs[dictMode][searchMethod == search_binaryTree]; 901 U32 offset_1 = rep[0], offset_2 = rep[1], savedOffset=0; 902 903 const int isDMS = dictMode == ZSTD_dictMatchState; 904 const int isDDS = dictMode == ZSTD_dedicatedDictSearch; 905 const int isDxS = isDMS || isDDS; 906 const ZSTD_matchState_t* const dms = ms->dictMatchState; 907 const U32 dictLowestIndex = isDxS ? dms->window.dictLimit : 0; 908 const BYTE* const dictBase = isDxS ? dms->window.base : NULL; 909 const BYTE* const dictLowest = isDxS ? dictBase + dictLowestIndex : NULL; 910 const BYTE* const dictEnd = isDxS ? dms->window.nextSrc : NULL; 911 const U32 dictIndexDelta = isDxS ? 912 prefixLowestIndex - (U32)(dictEnd - dictBase) : 913 0; 914 const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest)); 915 916 assert(searchMax != NULL); 917 918 DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u)", (U32)dictMode); 919 920 /* init */ 921 ip += (dictAndPrefixLength == 0); 922 if (dictMode == ZSTD_noDict) { 923 U32 const curr = (U32)(ip - base); 924 U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, ms->cParams.windowLog); 925 U32 const maxRep = curr - windowLow; 926 if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0; 927 if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0; 928 } 929 if (isDxS) { 930 /* dictMatchState repCode checks don't currently handle repCode == 0 931 * disabling. */ 932 assert(offset_1 <= dictAndPrefixLength); 933 assert(offset_2 <= dictAndPrefixLength); 934 } 935 936 /* Match Loop */ 937 #if defined(__GNUC__) && defined(__x86_64__) 938 /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the 939 * code alignment is perturbed. To fix the instability align the loop on 32-bytes. 940 */ 941 __asm__(".p2align 5"); 942 #endif 943 while (ip < ilimit) { 944 size_t matchLength=0; 945 size_t offset=0; 946 const BYTE* start=ip+1; 947 948 /* check repCode */ 949 if (isDxS) { 950 const U32 repIndex = (U32)(ip - base) + 1 - offset_1; 951 const BYTE* repMatch = ((dictMode == ZSTD_dictMatchState || dictMode == ZSTD_dedicatedDictSearch) 952 && repIndex < prefixLowestIndex) ? 953 dictBase + (repIndex - dictIndexDelta) : 954 base + repIndex; 955 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */) 956 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { 957 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend; 958 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4; 959 if (depth==0) goto _storeSequence; 960 } 961 } 962 if ( dictMode == ZSTD_noDict 963 && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) { 964 matchLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4; 965 if (depth==0) goto _storeSequence; 966 } 967 968 /* first search (depth 0) */ 969 { size_t offsetFound = 999999999; 970 size_t const ml2 = searchMax(ms, ip, iend, &offsetFound); 971 if (ml2 > matchLength) 972 matchLength = ml2, start = ip, offset=offsetFound; 973 } 974 975 if (matchLength < 4) { 976 ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */ 977 continue; 978 } 979 980 /* let's try to find a better solution */ 981 if (depth>=1) 982 while (ip<ilimit) { 983 ip ++; 984 if ( (dictMode == ZSTD_noDict) 985 && (offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) { 986 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4; 987 int const gain2 = (int)(mlRep * 3); 988 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1); 989 if ((mlRep >= 4) && (gain2 > gain1)) 990 matchLength = mlRep, offset = 0, start = ip; 991 } 992 if (isDxS) { 993 const U32 repIndex = (U32)(ip - base) - offset_1; 994 const BYTE* repMatch = repIndex < prefixLowestIndex ? 995 dictBase + (repIndex - dictIndexDelta) : 996 base + repIndex; 997 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */) 998 && (MEM_read32(repMatch) == MEM_read32(ip)) ) { 999 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend; 1000 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4; 1001 int const gain2 = (int)(mlRep * 3); 1002 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1); 1003 if ((mlRep >= 4) && (gain2 > gain1)) 1004 matchLength = mlRep, offset = 0, start = ip; 1005 } 1006 } 1007 { size_t offset2=999999999; 1008 size_t const ml2 = searchMax(ms, ip, iend, &offset2); 1009 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ 1010 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4); 1011 if ((ml2 >= 4) && (gain2 > gain1)) { 1012 matchLength = ml2, offset = offset2, start = ip; 1013 continue; /* search a better one */ 1014 } } 1015 1016 /* let's find an even better one */ 1017 if ((depth==2) && (ip<ilimit)) { 1018 ip ++; 1019 if ( (dictMode == ZSTD_noDict) 1020 && (offset) && ((offset_1>0) & (MEM_read32(ip) == MEM_read32(ip - offset_1)))) { 1021 size_t const mlRep = ZSTD_count(ip+4, ip+4-offset_1, iend) + 4; 1022 int const gain2 = (int)(mlRep * 4); 1023 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1); 1024 if ((mlRep >= 4) && (gain2 > gain1)) 1025 matchLength = mlRep, offset = 0, start = ip; 1026 } 1027 if (isDxS) { 1028 const U32 repIndex = (U32)(ip - base) - offset_1; 1029 const BYTE* repMatch = repIndex < prefixLowestIndex ? 1030 dictBase + (repIndex - dictIndexDelta) : 1031 base + repIndex; 1032 if (((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */) 1033 && (MEM_read32(repMatch) == MEM_read32(ip)) ) { 1034 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend; 1035 size_t const mlRep = ZSTD_count_2segments(ip+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4; 1036 int const gain2 = (int)(mlRep * 4); 1037 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1); 1038 if ((mlRep >= 4) && (gain2 > gain1)) 1039 matchLength = mlRep, offset = 0, start = ip; 1040 } 1041 } 1042 { size_t offset2=999999999; 1043 size_t const ml2 = searchMax(ms, ip, iend, &offset2); 1044 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ 1045 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7); 1046 if ((ml2 >= 4) && (gain2 > gain1)) { 1047 matchLength = ml2, offset = offset2, start = ip; 1048 continue; 1049 } } } 1050 break; /* nothing found : store previous solution */ 1051 } 1052 1053 /* NOTE: 1054 * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior. 1055 * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which 1056 * overflows the pointer, which is undefined behavior. 1057 */ 1058 /* catch up */ 1059 if (offset) { 1060 if (dictMode == ZSTD_noDict) { 1061 while ( ((start > anchor) & (start - (offset-ZSTD_REP_MOVE) > prefixLowest)) 1062 && (start[-1] == (start-(offset-ZSTD_REP_MOVE))[-1]) ) /* only search for offset within prefix */ 1063 { start--; matchLength++; } 1064 } 1065 if (isDxS) { 1066 U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE)); 1067 const BYTE* match = (matchIndex < prefixLowestIndex) ? dictBase + matchIndex - dictIndexDelta : base + matchIndex; 1068 const BYTE* const mStart = (matchIndex < prefixLowestIndex) ? dictLowest : prefixLowest; 1069 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */ 1070 } 1071 offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE); 1072 } 1073 /* store sequence */ 1074 _storeSequence: 1075 { size_t const litLength = start - anchor; 1076 ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offset, matchLength-MINMATCH); 1077 anchor = ip = start + matchLength; 1078 } 1079 1080 /* check immediate repcode */ 1081 if (isDxS) { 1082 while (ip <= ilimit) { 1083 U32 const current2 = (U32)(ip-base); 1084 U32 const repIndex = current2 - offset_2; 1085 const BYTE* repMatch = repIndex < prefixLowestIndex ? 1086 dictBase - dictIndexDelta + repIndex : 1087 base + repIndex; 1088 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex) >= 3 /* intentional overflow */) 1089 && (MEM_read32(repMatch) == MEM_read32(ip)) ) { 1090 const BYTE* const repEnd2 = repIndex < prefixLowestIndex ? dictEnd : iend; 1091 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd2, prefixLowest) + 4; 1092 offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap offset_2 <=> offset_1 */ 1093 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH); 1094 ip += matchLength; 1095 anchor = ip; 1096 continue; 1097 } 1098 break; 1099 } 1100 } 1101 1102 if (dictMode == ZSTD_noDict) { 1103 while ( ((ip <= ilimit) & (offset_2>0)) 1104 && (MEM_read32(ip) == MEM_read32(ip - offset_2)) ) { 1105 /* store sequence */ 1106 matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4; 1107 offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap repcodes */ 1108 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH); 1109 ip += matchLength; 1110 anchor = ip; 1111 continue; /* faster when present ... (?) */ 1112 } } } 1113 1114 /* Save reps for next block */ 1115 rep[0] = offset_1 ? offset_1 : savedOffset; 1116 rep[1] = offset_2 ? offset_2 : savedOffset; 1117 1118 /* Return the last literals size */ 1119 return (size_t)(iend - anchor); 1120 } 1121 1122 1123 size_t ZSTD_compressBlock_btlazy2( 1124 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1125 void const* src, size_t srcSize) 1126 { 1127 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_noDict); 1128 } 1129 1130 size_t ZSTD_compressBlock_lazy2( 1131 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1132 void const* src, size_t srcSize) 1133 { 1134 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_noDict); 1135 } 1136 1137 size_t ZSTD_compressBlock_lazy( 1138 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1139 void const* src, size_t srcSize) 1140 { 1141 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_noDict); 1142 } 1143 1144 size_t ZSTD_compressBlock_greedy( 1145 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1146 void const* src, size_t srcSize) 1147 { 1148 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_noDict); 1149 } 1150 1151 size_t ZSTD_compressBlock_btlazy2_dictMatchState( 1152 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1153 void const* src, size_t srcSize) 1154 { 1155 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2, ZSTD_dictMatchState); 1156 } 1157 1158 size_t ZSTD_compressBlock_lazy2_dictMatchState( 1159 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1160 void const* src, size_t srcSize) 1161 { 1162 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dictMatchState); 1163 } 1164 1165 size_t ZSTD_compressBlock_lazy_dictMatchState( 1166 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1167 void const* src, size_t srcSize) 1168 { 1169 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dictMatchState); 1170 } 1171 1172 size_t ZSTD_compressBlock_greedy_dictMatchState( 1173 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1174 void const* src, size_t srcSize) 1175 { 1176 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dictMatchState); 1177 } 1178 1179 1180 size_t ZSTD_compressBlock_lazy2_dedicatedDictSearch( 1181 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1182 void const* src, size_t srcSize) 1183 { 1184 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2, ZSTD_dedicatedDictSearch); 1185 } 1186 1187 size_t ZSTD_compressBlock_lazy_dedicatedDictSearch( 1188 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1189 void const* src, size_t srcSize) 1190 { 1191 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1, ZSTD_dedicatedDictSearch); 1192 } 1193 1194 size_t ZSTD_compressBlock_greedy_dedicatedDictSearch( 1195 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1196 void const* src, size_t srcSize) 1197 { 1198 return ZSTD_compressBlock_lazy_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0, ZSTD_dedicatedDictSearch); 1199 } 1200 1201 1202 FORCE_INLINE_TEMPLATE 1203 size_t ZSTD_compressBlock_lazy_extDict_generic( 1204 ZSTD_matchState_t* ms, seqStore_t* seqStore, 1205 U32 rep[ZSTD_REP_NUM], 1206 const void* src, size_t srcSize, 1207 const searchMethod_e searchMethod, const U32 depth) 1208 { 1209 const BYTE* const istart = (const BYTE*)src; 1210 const BYTE* ip = istart; 1211 const BYTE* anchor = istart; 1212 const BYTE* const iend = istart + srcSize; 1213 const BYTE* const ilimit = iend - 8; 1214 const BYTE* const base = ms->window.base; 1215 const U32 dictLimit = ms->window.dictLimit; 1216 const BYTE* const prefixStart = base + dictLimit; 1217 const BYTE* const dictBase = ms->window.dictBase; 1218 const BYTE* const dictEnd = dictBase + dictLimit; 1219 const BYTE* const dictStart = dictBase + ms->window.lowLimit; 1220 const U32 windowLog = ms->cParams.windowLog; 1221 1222 typedef size_t (*searchMax_f)( 1223 ZSTD_matchState_t* ms, 1224 const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr); 1225 searchMax_f searchMax = searchMethod==search_binaryTree ? ZSTD_BtFindBestMatch_extDict_selectMLS : ZSTD_HcFindBestMatch_extDict_selectMLS; 1226 1227 U32 offset_1 = rep[0], offset_2 = rep[1]; 1228 1229 DEBUGLOG(5, "ZSTD_compressBlock_lazy_extDict_generic"); 1230 1231 /* init */ 1232 ip += (ip == prefixStart); 1233 1234 /* Match Loop */ 1235 #if defined(__GNUC__) && defined(__x86_64__) 1236 /* I've measured random a 5% speed loss on levels 5 & 6 (greedy) when the 1237 * code alignment is perturbed. To fix the instability align the loop on 32-bytes. 1238 */ 1239 __asm__(".p2align 5"); 1240 #endif 1241 while (ip < ilimit) { 1242 size_t matchLength=0; 1243 size_t offset=0; 1244 const BYTE* start=ip+1; 1245 U32 curr = (U32)(ip-base); 1246 1247 /* check repCode */ 1248 { const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr+1, windowLog); 1249 const U32 repIndex = (U32)(curr+1 - offset_1); 1250 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; 1251 const BYTE* const repMatch = repBase + repIndex; 1252 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */ 1253 if (MEM_read32(ip+1) == MEM_read32(repMatch)) { 1254 /* repcode detected we should take it */ 1255 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; 1256 matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4; 1257 if (depth==0) goto _storeSequence; 1258 } } 1259 1260 /* first search (depth 0) */ 1261 { size_t offsetFound = 999999999; 1262 size_t const ml2 = searchMax(ms, ip, iend, &offsetFound); 1263 if (ml2 > matchLength) 1264 matchLength = ml2, start = ip, offset=offsetFound; 1265 } 1266 1267 if (matchLength < 4) { 1268 ip += ((ip-anchor) >> kSearchStrength) + 1; /* jump faster over incompressible sections */ 1269 continue; 1270 } 1271 1272 /* let's try to find a better solution */ 1273 if (depth>=1) 1274 while (ip<ilimit) { 1275 ip ++; 1276 curr++; 1277 /* check repCode */ 1278 if (offset) { 1279 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog); 1280 const U32 repIndex = (U32)(curr - offset_1); 1281 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; 1282 const BYTE* const repMatch = repBase + repIndex; 1283 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */ 1284 if (MEM_read32(ip) == MEM_read32(repMatch)) { 1285 /* repcode detected */ 1286 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; 1287 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4; 1288 int const gain2 = (int)(repLength * 3); 1289 int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1); 1290 if ((repLength >= 4) && (gain2 > gain1)) 1291 matchLength = repLength, offset = 0, start = ip; 1292 } } 1293 1294 /* search match, depth 1 */ 1295 { size_t offset2=999999999; 1296 size_t const ml2 = searchMax(ms, ip, iend, &offset2); 1297 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ 1298 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 4); 1299 if ((ml2 >= 4) && (gain2 > gain1)) { 1300 matchLength = ml2, offset = offset2, start = ip; 1301 continue; /* search a better one */ 1302 } } 1303 1304 /* let's find an even better one */ 1305 if ((depth==2) && (ip<ilimit)) { 1306 ip ++; 1307 curr++; 1308 /* check repCode */ 1309 if (offset) { 1310 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, curr, windowLog); 1311 const U32 repIndex = (U32)(curr - offset_1); 1312 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; 1313 const BYTE* const repMatch = repBase + repIndex; 1314 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */ 1315 if (MEM_read32(ip) == MEM_read32(repMatch)) { 1316 /* repcode detected */ 1317 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; 1318 size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4; 1319 int const gain2 = (int)(repLength * 4); 1320 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1); 1321 if ((repLength >= 4) && (gain2 > gain1)) 1322 matchLength = repLength, offset = 0, start = ip; 1323 } } 1324 1325 /* search match, depth 2 */ 1326 { size_t offset2=999999999; 1327 size_t const ml2 = searchMax(ms, ip, iend, &offset2); 1328 int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)offset2+1)); /* raw approx */ 1329 int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 7); 1330 if ((ml2 >= 4) && (gain2 > gain1)) { 1331 matchLength = ml2, offset = offset2, start = ip; 1332 continue; 1333 } } } 1334 break; /* nothing found : store previous solution */ 1335 } 1336 1337 /* catch up */ 1338 if (offset) { 1339 U32 const matchIndex = (U32)((start-base) - (offset - ZSTD_REP_MOVE)); 1340 const BYTE* match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex; 1341 const BYTE* const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart; 1342 while ((start>anchor) && (match>mStart) && (start[-1] == match[-1])) { start--; match--; matchLength++; } /* catch up */ 1343 offset_2 = offset_1; offset_1 = (U32)(offset - ZSTD_REP_MOVE); 1344 } 1345 1346 /* store sequence */ 1347 _storeSequence: 1348 { size_t const litLength = start - anchor; 1349 ZSTD_storeSeq(seqStore, litLength, anchor, iend, (U32)offset, matchLength-MINMATCH); 1350 anchor = ip = start + matchLength; 1351 } 1352 1353 /* check immediate repcode */ 1354 while (ip <= ilimit) { 1355 const U32 repCurrent = (U32)(ip-base); 1356 const U32 windowLow = ZSTD_getLowestMatchIndex(ms, repCurrent, windowLog); 1357 const U32 repIndex = repCurrent - offset_2; 1358 const BYTE* const repBase = repIndex < dictLimit ? dictBase : base; 1359 const BYTE* const repMatch = repBase + repIndex; 1360 if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */ 1361 if (MEM_read32(ip) == MEM_read32(repMatch)) { 1362 /* repcode detected we should take it */ 1363 const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend; 1364 matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4; 1365 offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap offset history */ 1366 ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH); 1367 ip += matchLength; 1368 anchor = ip; 1369 continue; /* faster when present ... (?) */ 1370 } 1371 break; 1372 } } 1373 1374 /* Save reps for next block */ 1375 rep[0] = offset_1; 1376 rep[1] = offset_2; 1377 1378 /* Return the last literals size */ 1379 return (size_t)(iend - anchor); 1380 } 1381 1382 1383 size_t ZSTD_compressBlock_greedy_extDict( 1384 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1385 void const* src, size_t srcSize) 1386 { 1387 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 0); 1388 } 1389 1390 size_t ZSTD_compressBlock_lazy_extDict( 1391 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1392 void const* src, size_t srcSize) 1393 1394 { 1395 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 1); 1396 } 1397 1398 size_t ZSTD_compressBlock_lazy2_extDict( 1399 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1400 void const* src, size_t srcSize) 1401 1402 { 1403 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_hashChain, 2); 1404 } 1405 1406 size_t ZSTD_compressBlock_btlazy2_extDict( 1407 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 1408 void const* src, size_t srcSize) 1409 1410 { 1411 return ZSTD_compressBlock_lazy_extDict_generic(ms, seqStore, rep, src, srcSize, search_binaryTree, 2); 1412 } 1413