1 /* 2 * LZ4 - Fast LZ compression algorithm 3 * Copyright (C) 2011 - 2016, Yann Collet. 4 * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php) 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 15 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 18 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * You can contact the author at : 26 * - LZ4 homepage : http://www.lz4.org 27 * - LZ4 source repository : https://github.com/lz4/lz4 28 * 29 * Changed for kernel usage by: 30 * Sven Schmidt <4sschmid@informatik.uni-hamburg.de> 31 */ 32 33 /*-************************************ 34 * Dependencies 35 **************************************/ 36 #include <linux/lz4.h> 37 #include "lz4defs.h" 38 #include <linux/init.h> 39 #include <linux/module.h> 40 #include <linux/kernel.h> 41 #include <asm/unaligned.h> 42 43 /*-***************************** 44 * Decompression functions 45 *******************************/ 46 47 #define DEBUGLOG(l, ...) {} /* disabled */ 48 49 #ifndef assert 50 #define assert(condition) ((void)0) 51 #endif 52 53 /* 54 * LZ4_decompress_generic() : 55 * This generic decompression function covers all use cases. 56 * It shall be instantiated several times, using different sets of directives. 57 * Note that it is important for performance that this function really get inlined, 58 * in order to remove useless branches during compilation optimization. 59 */ 60 static FORCE_INLINE int LZ4_decompress_generic( 61 const char * const src, 62 char * const dst, 63 int srcSize, 64 /* 65 * If endOnInput == endOnInputSize, 66 * this value is `dstCapacity` 67 */ 68 int outputSize, 69 /* endOnOutputSize, endOnInputSize */ 70 endCondition_directive endOnInput, 71 /* full, partial */ 72 earlyEnd_directive partialDecoding, 73 /* noDict, withPrefix64k, usingExtDict */ 74 dict_directive dict, 75 /* always <= dst, == dst when no prefix */ 76 const BYTE * const lowPrefix, 77 /* only if dict == usingExtDict */ 78 const BYTE * const dictStart, 79 /* note : = 0 if noDict */ 80 const size_t dictSize 81 ) 82 { 83 const BYTE *ip = (const BYTE *) src; 84 const BYTE * const iend = ip + srcSize; 85 86 BYTE *op = (BYTE *) dst; 87 BYTE * const oend = op + outputSize; 88 BYTE *cpy; 89 90 const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize; 91 static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4}; 92 static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3}; 93 94 const int safeDecode = (endOnInput == endOnInputSize); 95 const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB))); 96 97 /* Set up the "end" pointers for the shortcut. */ 98 const BYTE *const shortiend = iend - 99 (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/; 100 const BYTE *const shortoend = oend - 101 (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/; 102 103 DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__, 104 srcSize, outputSize); 105 106 /* Special cases */ 107 assert(lowPrefix <= op); 108 assert(src != NULL); 109 110 /* Empty output buffer */ 111 if ((endOnInput) && (unlikely(outputSize == 0))) 112 return ((srcSize == 1) && (*ip == 0)) ? 0 : -1; 113 114 if ((!endOnInput) && (unlikely(outputSize == 0))) 115 return (*ip == 0 ? 1 : -1); 116 117 if ((endOnInput) && unlikely(srcSize == 0)) 118 return -1; 119 120 /* Main Loop : decode sequences */ 121 while (1) { 122 size_t length; 123 const BYTE *match; 124 size_t offset; 125 126 /* get literal length */ 127 unsigned int const token = *ip++; 128 length = token>>ML_BITS; 129 130 /* ip < iend before the increment */ 131 assert(!endOnInput || ip <= iend); 132 133 /* 134 * A two-stage shortcut for the most common case: 135 * 1) If the literal length is 0..14, and there is enough 136 * space, enter the shortcut and copy 16 bytes on behalf 137 * of the literals (in the fast mode, only 8 bytes can be 138 * safely copied this way). 139 * 2) Further if the match length is 4..18, copy 18 bytes 140 * in a similar manner; but we ensure that there's enough 141 * space in the output for those 18 bytes earlier, upon 142 * entering the shortcut (in other words, there is a 143 * combined check for both stages). 144 * 145 * The & in the likely() below is intentionally not && so that 146 * some compilers can produce better parallelized runtime code 147 */ 148 if ((endOnInput ? length != RUN_MASK : length <= 8) 149 /* 150 * strictly "less than" on input, to re-enter 151 * the loop with at least one byte 152 */ 153 && likely((endOnInput ? ip < shortiend : 1) & 154 (op <= shortoend))) { 155 /* Copy the literals */ 156 LZ4_memcpy(op, ip, endOnInput ? 16 : 8); 157 op += length; ip += length; 158 159 /* 160 * The second stage: 161 * prepare for match copying, decode full info. 162 * If it doesn't work out, the info won't be wasted. 163 */ 164 length = token & ML_MASK; /* match length */ 165 offset = LZ4_readLE16(ip); 166 ip += 2; 167 match = op - offset; 168 assert(match <= op); /* check overflow */ 169 170 /* Do not deal with overlapping matches. */ 171 if ((length != ML_MASK) && 172 (offset >= 8) && 173 (dict == withPrefix64k || match >= lowPrefix)) { 174 /* Copy the match. */ 175 LZ4_memcpy(op + 0, match + 0, 8); 176 LZ4_memcpy(op + 8, match + 8, 8); 177 LZ4_memcpy(op + 16, match + 16, 2); 178 op += length + MINMATCH; 179 /* Both stages worked, load the next token. */ 180 continue; 181 } 182 183 /* 184 * The second stage didn't work out, but the info 185 * is ready. Propel it right to the point of match 186 * copying. 187 */ 188 goto _copy_match; 189 } 190 191 /* decode literal length */ 192 if (length == RUN_MASK) { 193 unsigned int s; 194 195 if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) { 196 /* overflow detection */ 197 goto _output_error; 198 } 199 do { 200 s = *ip++; 201 length += s; 202 } while (likely(endOnInput 203 ? ip < iend - RUN_MASK 204 : 1) & (s == 255)); 205 206 if ((safeDecode) 207 && unlikely((uptrval)(op) + 208 length < (uptrval)(op))) { 209 /* overflow detection */ 210 goto _output_error; 211 } 212 if ((safeDecode) 213 && unlikely((uptrval)(ip) + 214 length < (uptrval)(ip))) { 215 /* overflow detection */ 216 goto _output_error; 217 } 218 } 219 220 /* copy literals */ 221 cpy = op + length; 222 LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH); 223 224 if (((endOnInput) && ((cpy > oend - MFLIMIT) 225 || (ip + length > iend - (2 + 1 + LASTLITERALS)))) 226 || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) { 227 if (partialDecoding) { 228 if (cpy > oend) { 229 /* 230 * Partial decoding : 231 * stop in the middle of literal segment 232 */ 233 cpy = oend; 234 length = oend - op; 235 } 236 if ((endOnInput) 237 && (ip + length > iend)) { 238 /* 239 * Error : 240 * read attempt beyond 241 * end of input buffer 242 */ 243 goto _output_error; 244 } 245 } else { 246 if ((!endOnInput) 247 && (cpy != oend)) { 248 /* 249 * Error : 250 * block decoding must 251 * stop exactly there 252 */ 253 goto _output_error; 254 } 255 if ((endOnInput) 256 && ((ip + length != iend) 257 || (cpy > oend))) { 258 /* 259 * Error : 260 * input must be consumed 261 */ 262 goto _output_error; 263 } 264 } 265 266 LZ4_memcpy(op, ip, length); 267 ip += length; 268 op += length; 269 270 /* Necessarily EOF, due to parsing restrictions */ 271 if (!partialDecoding || (cpy == oend)) 272 break; 273 } else { 274 /* may overwrite up to WILDCOPYLENGTH beyond cpy */ 275 LZ4_wildCopy(op, ip, cpy); 276 ip += length; 277 op = cpy; 278 } 279 280 /* get offset */ 281 offset = LZ4_readLE16(ip); 282 ip += 2; 283 match = op - offset; 284 285 /* get matchlength */ 286 length = token & ML_MASK; 287 288 _copy_match: 289 if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { 290 /* Error : offset outside buffers */ 291 goto _output_error; 292 } 293 294 /* costs ~1%; silence an msan warning when offset == 0 */ 295 /* 296 * note : when partialDecoding, there is no guarantee that 297 * at least 4 bytes remain available in output buffer 298 */ 299 if (!partialDecoding) { 300 assert(oend > op); 301 assert(oend - op >= 4); 302 303 LZ4_write32(op, (U32)offset); 304 } 305 306 if (length == ML_MASK) { 307 unsigned int s; 308 309 do { 310 s = *ip++; 311 312 if ((endOnInput) && (ip > iend - LASTLITERALS)) 313 goto _output_error; 314 315 length += s; 316 } while (s == 255); 317 318 if ((safeDecode) 319 && unlikely( 320 (uptrval)(op) + length < (uptrval)op)) { 321 /* overflow detection */ 322 goto _output_error; 323 } 324 } 325 326 length += MINMATCH; 327 328 /* match starting within external dictionary */ 329 if ((dict == usingExtDict) && (match < lowPrefix)) { 330 if (unlikely(op + length > oend - LASTLITERALS)) { 331 /* doesn't respect parsing restriction */ 332 if (!partialDecoding) 333 goto _output_error; 334 length = min(length, (size_t)(oend - op)); 335 } 336 337 if (length <= (size_t)(lowPrefix - match)) { 338 /* 339 * match fits entirely within external 340 * dictionary : just copy 341 */ 342 memmove(op, dictEnd - (lowPrefix - match), 343 length); 344 op += length; 345 } else { 346 /* 347 * match stretches into both external 348 * dictionary and current block 349 */ 350 size_t const copySize = (size_t)(lowPrefix - match); 351 size_t const restSize = length - copySize; 352 353 LZ4_memcpy(op, dictEnd - copySize, copySize); 354 op += copySize; 355 if (restSize > (size_t)(op - lowPrefix)) { 356 /* overlap copy */ 357 BYTE * const endOfMatch = op + restSize; 358 const BYTE *copyFrom = lowPrefix; 359 360 while (op < endOfMatch) 361 *op++ = *copyFrom++; 362 } else { 363 LZ4_memcpy(op, lowPrefix, restSize); 364 op += restSize; 365 } 366 } 367 continue; 368 } 369 370 /* copy match within block */ 371 cpy = op + length; 372 373 /* 374 * partialDecoding : 375 * may not respect endBlock parsing restrictions 376 */ 377 assert(op <= oend); 378 if (partialDecoding && 379 (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 380 size_t const mlen = min(length, (size_t)(oend - op)); 381 const BYTE * const matchEnd = match + mlen; 382 BYTE * const copyEnd = op + mlen; 383 384 if (matchEnd > op) { 385 /* overlap copy */ 386 while (op < copyEnd) 387 *op++ = *match++; 388 } else { 389 LZ4_memcpy(op, match, mlen); 390 } 391 op = copyEnd; 392 if (op == oend) 393 break; 394 continue; 395 } 396 397 if (unlikely(offset < 8)) { 398 op[0] = match[0]; 399 op[1] = match[1]; 400 op[2] = match[2]; 401 op[3] = match[3]; 402 match += inc32table[offset]; 403 LZ4_memcpy(op + 4, match, 4); 404 match -= dec64table[offset]; 405 } else { 406 LZ4_copy8(op, match); 407 match += 8; 408 } 409 410 op += 8; 411 412 if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 413 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1); 414 415 if (cpy > oend - LASTLITERALS) { 416 /* 417 * Error : last LASTLITERALS bytes 418 * must be literals (uncompressed) 419 */ 420 goto _output_error; 421 } 422 423 if (op < oCopyLimit) { 424 LZ4_wildCopy(op, match, oCopyLimit); 425 match += oCopyLimit - op; 426 op = oCopyLimit; 427 } 428 while (op < cpy) 429 *op++ = *match++; 430 } else { 431 LZ4_copy8(op, match); 432 if (length > 16) 433 LZ4_wildCopy(op + 8, match + 8, cpy); 434 } 435 op = cpy; /* wildcopy correction */ 436 } 437 438 /* end of decoding */ 439 if (endOnInput) { 440 /* Nb of output bytes decoded */ 441 return (int) (((char *)op) - dst); 442 } else { 443 /* Nb of input bytes read */ 444 return (int) (((const char *)ip) - src); 445 } 446 447 /* Overflow error detected */ 448 _output_error: 449 return (int) (-(((const char *)ip) - src)) - 1; 450 } 451 452 int LZ4_decompress_safe(const char *source, char *dest, 453 int compressedSize, int maxDecompressedSize) 454 { 455 return LZ4_decompress_generic(source, dest, 456 compressedSize, maxDecompressedSize, 457 endOnInputSize, decode_full_block, 458 noDict, (BYTE *)dest, NULL, 0); 459 } 460 461 int LZ4_decompress_safe_partial(const char *src, char *dst, 462 int compressedSize, int targetOutputSize, int dstCapacity) 463 { 464 dstCapacity = min(targetOutputSize, dstCapacity); 465 return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity, 466 endOnInputSize, partial_decode, 467 noDict, (BYTE *)dst, NULL, 0); 468 } 469 470 int LZ4_decompress_fast(const char *source, char *dest, int originalSize) 471 { 472 return LZ4_decompress_generic(source, dest, 0, originalSize, 473 endOnOutputSize, decode_full_block, 474 withPrefix64k, 475 (BYTE *)dest - 64 * KB, NULL, 0); 476 } 477 478 /* ===== Instantiate a few more decoding cases, used more than once. ===== */ 479 480 int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest, 481 int compressedSize, int maxOutputSize) 482 { 483 return LZ4_decompress_generic(source, dest, 484 compressedSize, maxOutputSize, 485 endOnInputSize, decode_full_block, 486 withPrefix64k, 487 (BYTE *)dest - 64 * KB, NULL, 0); 488 } 489 490 static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest, 491 int compressedSize, 492 int maxOutputSize, 493 size_t prefixSize) 494 { 495 return LZ4_decompress_generic(source, dest, 496 compressedSize, maxOutputSize, 497 endOnInputSize, decode_full_block, 498 noDict, 499 (BYTE *)dest - prefixSize, NULL, 0); 500 } 501 502 int LZ4_decompress_safe_forceExtDict(const char *source, char *dest, 503 int compressedSize, int maxOutputSize, 504 const void *dictStart, size_t dictSize) 505 { 506 return LZ4_decompress_generic(source, dest, 507 compressedSize, maxOutputSize, 508 endOnInputSize, decode_full_block, 509 usingExtDict, (BYTE *)dest, 510 (const BYTE *)dictStart, dictSize); 511 } 512 513 static int LZ4_decompress_fast_extDict(const char *source, char *dest, 514 int originalSize, 515 const void *dictStart, size_t dictSize) 516 { 517 return LZ4_decompress_generic(source, dest, 518 0, originalSize, 519 endOnOutputSize, decode_full_block, 520 usingExtDict, (BYTE *)dest, 521 (const BYTE *)dictStart, dictSize); 522 } 523 524 /* 525 * The "double dictionary" mode, for use with e.g. ring buffers: the first part 526 * of the dictionary is passed as prefix, and the second via dictStart + dictSize. 527 * These routines are used only once, in LZ4_decompress_*_continue(). 528 */ 529 static FORCE_INLINE 530 int LZ4_decompress_safe_doubleDict(const char *source, char *dest, 531 int compressedSize, int maxOutputSize, 532 size_t prefixSize, 533 const void *dictStart, size_t dictSize) 534 { 535 return LZ4_decompress_generic(source, dest, 536 compressedSize, maxOutputSize, 537 endOnInputSize, decode_full_block, 538 usingExtDict, (BYTE *)dest - prefixSize, 539 (const BYTE *)dictStart, dictSize); 540 } 541 542 static FORCE_INLINE 543 int LZ4_decompress_fast_doubleDict(const char *source, char *dest, 544 int originalSize, size_t prefixSize, 545 const void *dictStart, size_t dictSize) 546 { 547 return LZ4_decompress_generic(source, dest, 548 0, originalSize, 549 endOnOutputSize, decode_full_block, 550 usingExtDict, (BYTE *)dest - prefixSize, 551 (const BYTE *)dictStart, dictSize); 552 } 553 554 /* ===== streaming decompression functions ===== */ 555 556 int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode, 557 const char *dictionary, int dictSize) 558 { 559 LZ4_streamDecode_t_internal *lz4sd = 560 &LZ4_streamDecode->internal_donotuse; 561 562 lz4sd->prefixSize = (size_t) dictSize; 563 lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize; 564 lz4sd->externalDict = NULL; 565 lz4sd->extDictSize = 0; 566 return 1; 567 } 568 569 /* 570 * *_continue() : 571 * These decoding functions allow decompression of multiple blocks 572 * in "streaming" mode. 573 * Previously decoded blocks must still be available at the memory 574 * position where they were decoded. 575 * If it's not possible, save the relevant part of 576 * decoded data into a safe buffer, 577 * and indicate where it stands using LZ4_setStreamDecode() 578 */ 579 int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode, 580 const char *source, char *dest, int compressedSize, int maxOutputSize) 581 { 582 LZ4_streamDecode_t_internal *lz4sd = 583 &LZ4_streamDecode->internal_donotuse; 584 int result; 585 586 if (lz4sd->prefixSize == 0) { 587 /* The first call, no dictionary yet. */ 588 assert(lz4sd->extDictSize == 0); 589 result = LZ4_decompress_safe(source, dest, 590 compressedSize, maxOutputSize); 591 if (result <= 0) 592 return result; 593 lz4sd->prefixSize = result; 594 lz4sd->prefixEnd = (BYTE *)dest + result; 595 } else if (lz4sd->prefixEnd == (BYTE *)dest) { 596 /* They're rolling the current segment. */ 597 if (lz4sd->prefixSize >= 64 * KB - 1) 598 result = LZ4_decompress_safe_withPrefix64k(source, dest, 599 compressedSize, maxOutputSize); 600 else if (lz4sd->extDictSize == 0) 601 result = LZ4_decompress_safe_withSmallPrefix(source, 602 dest, compressedSize, maxOutputSize, 603 lz4sd->prefixSize); 604 else 605 result = LZ4_decompress_safe_doubleDict(source, dest, 606 compressedSize, maxOutputSize, 607 lz4sd->prefixSize, 608 lz4sd->externalDict, lz4sd->extDictSize); 609 if (result <= 0) 610 return result; 611 lz4sd->prefixSize += result; 612 lz4sd->prefixEnd += result; 613 } else { 614 /* 615 * The buffer wraps around, or they're 616 * switching to another buffer. 617 */ 618 lz4sd->extDictSize = lz4sd->prefixSize; 619 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; 620 result = LZ4_decompress_safe_forceExtDict(source, dest, 621 compressedSize, maxOutputSize, 622 lz4sd->externalDict, lz4sd->extDictSize); 623 if (result <= 0) 624 return result; 625 lz4sd->prefixSize = result; 626 lz4sd->prefixEnd = (BYTE *)dest + result; 627 } 628 629 return result; 630 } 631 632 int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode, 633 const char *source, char *dest, int originalSize) 634 { 635 LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse; 636 int result; 637 638 if (lz4sd->prefixSize == 0) { 639 assert(lz4sd->extDictSize == 0); 640 result = LZ4_decompress_fast(source, dest, originalSize); 641 if (result <= 0) 642 return result; 643 lz4sd->prefixSize = originalSize; 644 lz4sd->prefixEnd = (BYTE *)dest + originalSize; 645 } else if (lz4sd->prefixEnd == (BYTE *)dest) { 646 if (lz4sd->prefixSize >= 64 * KB - 1 || 647 lz4sd->extDictSize == 0) 648 result = LZ4_decompress_fast(source, dest, 649 originalSize); 650 else 651 result = LZ4_decompress_fast_doubleDict(source, dest, 652 originalSize, lz4sd->prefixSize, 653 lz4sd->externalDict, lz4sd->extDictSize); 654 if (result <= 0) 655 return result; 656 lz4sd->prefixSize += originalSize; 657 lz4sd->prefixEnd += originalSize; 658 } else { 659 lz4sd->extDictSize = lz4sd->prefixSize; 660 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; 661 result = LZ4_decompress_fast_extDict(source, dest, 662 originalSize, lz4sd->externalDict, lz4sd->extDictSize); 663 if (result <= 0) 664 return result; 665 lz4sd->prefixSize = originalSize; 666 lz4sd->prefixEnd = (BYTE *)dest + originalSize; 667 } 668 return result; 669 } 670 671 int LZ4_decompress_safe_usingDict(const char *source, char *dest, 672 int compressedSize, int maxOutputSize, 673 const char *dictStart, int dictSize) 674 { 675 if (dictSize == 0) 676 return LZ4_decompress_safe(source, dest, 677 compressedSize, maxOutputSize); 678 if (dictStart+dictSize == dest) { 679 if (dictSize >= 64 * KB - 1) 680 return LZ4_decompress_safe_withPrefix64k(source, dest, 681 compressedSize, maxOutputSize); 682 return LZ4_decompress_safe_withSmallPrefix(source, dest, 683 compressedSize, maxOutputSize, dictSize); 684 } 685 return LZ4_decompress_safe_forceExtDict(source, dest, 686 compressedSize, maxOutputSize, dictStart, dictSize); 687 } 688 689 int LZ4_decompress_fast_usingDict(const char *source, char *dest, 690 int originalSize, 691 const char *dictStart, int dictSize) 692 { 693 if (dictSize == 0 || dictStart + dictSize == dest) 694 return LZ4_decompress_fast(source, dest, originalSize); 695 696 return LZ4_decompress_fast_extDict(source, dest, originalSize, 697 dictStart, dictSize); 698 } 699 700 #ifndef STATIC 701 EXPORT_SYMBOL(LZ4_decompress_safe); 702 EXPORT_SYMBOL(LZ4_decompress_safe_partial); 703 EXPORT_SYMBOL(LZ4_decompress_fast); 704 EXPORT_SYMBOL(LZ4_setStreamDecode); 705 EXPORT_SYMBOL(LZ4_decompress_safe_continue); 706 EXPORT_SYMBOL(LZ4_decompress_fast_continue); 707 EXPORT_SYMBOL(LZ4_decompress_safe_usingDict); 708 EXPORT_SYMBOL(LZ4_decompress_fast_usingDict); 709 710 MODULE_LICENSE("Dual BSD/GPL"); 711 MODULE_DESCRIPTION("LZ4 decompressor"); 712 #endif 713