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 /* 267 * supports overlapping memory regions; only matters 268 * for in-place decompression scenarios 269 */ 270 LZ4_memmove(op, ip, length); 271 ip += length; 272 op += length; 273 274 /* Necessarily EOF, due to parsing restrictions */ 275 if (!partialDecoding || (cpy == oend)) 276 break; 277 } else { 278 /* may overwrite up to WILDCOPYLENGTH beyond cpy */ 279 LZ4_wildCopy(op, ip, cpy); 280 ip += length; 281 op = cpy; 282 } 283 284 /* get offset */ 285 offset = LZ4_readLE16(ip); 286 ip += 2; 287 match = op - offset; 288 289 /* get matchlength */ 290 length = token & ML_MASK; 291 292 _copy_match: 293 if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { 294 /* Error : offset outside buffers */ 295 goto _output_error; 296 } 297 298 /* costs ~1%; silence an msan warning when offset == 0 */ 299 /* 300 * note : when partialDecoding, there is no guarantee that 301 * at least 4 bytes remain available in output buffer 302 */ 303 if (!partialDecoding) { 304 assert(oend > op); 305 assert(oend - op >= 4); 306 307 LZ4_write32(op, (U32)offset); 308 } 309 310 if (length == ML_MASK) { 311 unsigned int s; 312 313 do { 314 s = *ip++; 315 316 if ((endOnInput) && (ip > iend - LASTLITERALS)) 317 goto _output_error; 318 319 length += s; 320 } while (s == 255); 321 322 if ((safeDecode) 323 && unlikely( 324 (uptrval)(op) + length < (uptrval)op)) { 325 /* overflow detection */ 326 goto _output_error; 327 } 328 } 329 330 length += MINMATCH; 331 332 /* match starting within external dictionary */ 333 if ((dict == usingExtDict) && (match < lowPrefix)) { 334 if (unlikely(op + length > oend - LASTLITERALS)) { 335 /* doesn't respect parsing restriction */ 336 if (!partialDecoding) 337 goto _output_error; 338 length = min(length, (size_t)(oend - op)); 339 } 340 341 if (length <= (size_t)(lowPrefix - match)) { 342 /* 343 * match fits entirely within external 344 * dictionary : just copy 345 */ 346 memmove(op, dictEnd - (lowPrefix - match), 347 length); 348 op += length; 349 } else { 350 /* 351 * match stretches into both external 352 * dictionary and current block 353 */ 354 size_t const copySize = (size_t)(lowPrefix - match); 355 size_t const restSize = length - copySize; 356 357 LZ4_memcpy(op, dictEnd - copySize, copySize); 358 op += copySize; 359 if (restSize > (size_t)(op - lowPrefix)) { 360 /* overlap copy */ 361 BYTE * const endOfMatch = op + restSize; 362 const BYTE *copyFrom = lowPrefix; 363 364 while (op < endOfMatch) 365 *op++ = *copyFrom++; 366 } else { 367 LZ4_memcpy(op, lowPrefix, restSize); 368 op += restSize; 369 } 370 } 371 continue; 372 } 373 374 /* copy match within block */ 375 cpy = op + length; 376 377 /* 378 * partialDecoding : 379 * may not respect endBlock parsing restrictions 380 */ 381 assert(op <= oend); 382 if (partialDecoding && 383 (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 384 size_t const mlen = min(length, (size_t)(oend - op)); 385 const BYTE * const matchEnd = match + mlen; 386 BYTE * const copyEnd = op + mlen; 387 388 if (matchEnd > op) { 389 /* overlap copy */ 390 while (op < copyEnd) 391 *op++ = *match++; 392 } else { 393 LZ4_memcpy(op, match, mlen); 394 } 395 op = copyEnd; 396 if (op == oend) 397 break; 398 continue; 399 } 400 401 if (unlikely(offset < 8)) { 402 op[0] = match[0]; 403 op[1] = match[1]; 404 op[2] = match[2]; 405 op[3] = match[3]; 406 match += inc32table[offset]; 407 LZ4_memcpy(op + 4, match, 4); 408 match -= dec64table[offset]; 409 } else { 410 LZ4_copy8(op, match); 411 match += 8; 412 } 413 414 op += 8; 415 416 if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 417 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1); 418 419 if (cpy > oend - LASTLITERALS) { 420 /* 421 * Error : last LASTLITERALS bytes 422 * must be literals (uncompressed) 423 */ 424 goto _output_error; 425 } 426 427 if (op < oCopyLimit) { 428 LZ4_wildCopy(op, match, oCopyLimit); 429 match += oCopyLimit - op; 430 op = oCopyLimit; 431 } 432 while (op < cpy) 433 *op++ = *match++; 434 } else { 435 LZ4_copy8(op, match); 436 if (length > 16) 437 LZ4_wildCopy(op + 8, match + 8, cpy); 438 } 439 op = cpy; /* wildcopy correction */ 440 } 441 442 /* end of decoding */ 443 if (endOnInput) { 444 /* Nb of output bytes decoded */ 445 return (int) (((char *)op) - dst); 446 } else { 447 /* Nb of input bytes read */ 448 return (int) (((const char *)ip) - src); 449 } 450 451 /* Overflow error detected */ 452 _output_error: 453 return (int) (-(((const char *)ip) - src)) - 1; 454 } 455 456 int LZ4_decompress_safe(const char *source, char *dest, 457 int compressedSize, int maxDecompressedSize) 458 { 459 return LZ4_decompress_generic(source, dest, 460 compressedSize, maxDecompressedSize, 461 endOnInputSize, decode_full_block, 462 noDict, (BYTE *)dest, NULL, 0); 463 } 464 465 int LZ4_decompress_safe_partial(const char *src, char *dst, 466 int compressedSize, int targetOutputSize, int dstCapacity) 467 { 468 dstCapacity = min(targetOutputSize, dstCapacity); 469 return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity, 470 endOnInputSize, partial_decode, 471 noDict, (BYTE *)dst, NULL, 0); 472 } 473 474 int LZ4_decompress_fast(const char *source, char *dest, int originalSize) 475 { 476 return LZ4_decompress_generic(source, dest, 0, originalSize, 477 endOnOutputSize, decode_full_block, 478 withPrefix64k, 479 (BYTE *)dest - 64 * KB, NULL, 0); 480 } 481 482 /* ===== Instantiate a few more decoding cases, used more than once. ===== */ 483 484 int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest, 485 int compressedSize, int maxOutputSize) 486 { 487 return LZ4_decompress_generic(source, dest, 488 compressedSize, maxOutputSize, 489 endOnInputSize, decode_full_block, 490 withPrefix64k, 491 (BYTE *)dest - 64 * KB, NULL, 0); 492 } 493 494 static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest, 495 int compressedSize, 496 int maxOutputSize, 497 size_t prefixSize) 498 { 499 return LZ4_decompress_generic(source, dest, 500 compressedSize, maxOutputSize, 501 endOnInputSize, decode_full_block, 502 noDict, 503 (BYTE *)dest - prefixSize, NULL, 0); 504 } 505 506 int LZ4_decompress_safe_forceExtDict(const char *source, char *dest, 507 int compressedSize, int maxOutputSize, 508 const void *dictStart, size_t dictSize) 509 { 510 return LZ4_decompress_generic(source, dest, 511 compressedSize, maxOutputSize, 512 endOnInputSize, decode_full_block, 513 usingExtDict, (BYTE *)dest, 514 (const BYTE *)dictStart, dictSize); 515 } 516 517 static int LZ4_decompress_fast_extDict(const char *source, char *dest, 518 int originalSize, 519 const void *dictStart, size_t dictSize) 520 { 521 return LZ4_decompress_generic(source, dest, 522 0, originalSize, 523 endOnOutputSize, decode_full_block, 524 usingExtDict, (BYTE *)dest, 525 (const BYTE *)dictStart, dictSize); 526 } 527 528 /* 529 * The "double dictionary" mode, for use with e.g. ring buffers: the first part 530 * of the dictionary is passed as prefix, and the second via dictStart + dictSize. 531 * These routines are used only once, in LZ4_decompress_*_continue(). 532 */ 533 static FORCE_INLINE 534 int LZ4_decompress_safe_doubleDict(const char *source, char *dest, 535 int compressedSize, int maxOutputSize, 536 size_t prefixSize, 537 const void *dictStart, size_t dictSize) 538 { 539 return LZ4_decompress_generic(source, dest, 540 compressedSize, maxOutputSize, 541 endOnInputSize, decode_full_block, 542 usingExtDict, (BYTE *)dest - prefixSize, 543 (const BYTE *)dictStart, dictSize); 544 } 545 546 static FORCE_INLINE 547 int LZ4_decompress_fast_doubleDict(const char *source, char *dest, 548 int originalSize, size_t prefixSize, 549 const void *dictStart, size_t dictSize) 550 { 551 return LZ4_decompress_generic(source, dest, 552 0, originalSize, 553 endOnOutputSize, decode_full_block, 554 usingExtDict, (BYTE *)dest - prefixSize, 555 (const BYTE *)dictStart, dictSize); 556 } 557 558 /* ===== streaming decompression functions ===== */ 559 560 int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode, 561 const char *dictionary, int dictSize) 562 { 563 LZ4_streamDecode_t_internal *lz4sd = 564 &LZ4_streamDecode->internal_donotuse; 565 566 lz4sd->prefixSize = (size_t) dictSize; 567 lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize; 568 lz4sd->externalDict = NULL; 569 lz4sd->extDictSize = 0; 570 return 1; 571 } 572 573 /* 574 * *_continue() : 575 * These decoding functions allow decompression of multiple blocks 576 * in "streaming" mode. 577 * Previously decoded blocks must still be available at the memory 578 * position where they were decoded. 579 * If it's not possible, save the relevant part of 580 * decoded data into a safe buffer, 581 * and indicate where it stands using LZ4_setStreamDecode() 582 */ 583 int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode, 584 const char *source, char *dest, int compressedSize, int maxOutputSize) 585 { 586 LZ4_streamDecode_t_internal *lz4sd = 587 &LZ4_streamDecode->internal_donotuse; 588 int result; 589 590 if (lz4sd->prefixSize == 0) { 591 /* The first call, no dictionary yet. */ 592 assert(lz4sd->extDictSize == 0); 593 result = LZ4_decompress_safe(source, dest, 594 compressedSize, maxOutputSize); 595 if (result <= 0) 596 return result; 597 lz4sd->prefixSize = result; 598 lz4sd->prefixEnd = (BYTE *)dest + result; 599 } else if (lz4sd->prefixEnd == (BYTE *)dest) { 600 /* They're rolling the current segment. */ 601 if (lz4sd->prefixSize >= 64 * KB - 1) 602 result = LZ4_decompress_safe_withPrefix64k(source, dest, 603 compressedSize, maxOutputSize); 604 else if (lz4sd->extDictSize == 0) 605 result = LZ4_decompress_safe_withSmallPrefix(source, 606 dest, compressedSize, maxOutputSize, 607 lz4sd->prefixSize); 608 else 609 result = LZ4_decompress_safe_doubleDict(source, dest, 610 compressedSize, maxOutputSize, 611 lz4sd->prefixSize, 612 lz4sd->externalDict, lz4sd->extDictSize); 613 if (result <= 0) 614 return result; 615 lz4sd->prefixSize += result; 616 lz4sd->prefixEnd += result; 617 } else { 618 /* 619 * The buffer wraps around, or they're 620 * switching to another buffer. 621 */ 622 lz4sd->extDictSize = lz4sd->prefixSize; 623 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; 624 result = LZ4_decompress_safe_forceExtDict(source, dest, 625 compressedSize, maxOutputSize, 626 lz4sd->externalDict, lz4sd->extDictSize); 627 if (result <= 0) 628 return result; 629 lz4sd->prefixSize = result; 630 lz4sd->prefixEnd = (BYTE *)dest + result; 631 } 632 633 return result; 634 } 635 636 int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode, 637 const char *source, char *dest, int originalSize) 638 { 639 LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse; 640 int result; 641 642 if (lz4sd->prefixSize == 0) { 643 assert(lz4sd->extDictSize == 0); 644 result = LZ4_decompress_fast(source, dest, originalSize); 645 if (result <= 0) 646 return result; 647 lz4sd->prefixSize = originalSize; 648 lz4sd->prefixEnd = (BYTE *)dest + originalSize; 649 } else if (lz4sd->prefixEnd == (BYTE *)dest) { 650 if (lz4sd->prefixSize >= 64 * KB - 1 || 651 lz4sd->extDictSize == 0) 652 result = LZ4_decompress_fast(source, dest, 653 originalSize); 654 else 655 result = LZ4_decompress_fast_doubleDict(source, dest, 656 originalSize, lz4sd->prefixSize, 657 lz4sd->externalDict, lz4sd->extDictSize); 658 if (result <= 0) 659 return result; 660 lz4sd->prefixSize += originalSize; 661 lz4sd->prefixEnd += originalSize; 662 } else { 663 lz4sd->extDictSize = lz4sd->prefixSize; 664 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; 665 result = LZ4_decompress_fast_extDict(source, dest, 666 originalSize, lz4sd->externalDict, lz4sd->extDictSize); 667 if (result <= 0) 668 return result; 669 lz4sd->prefixSize = originalSize; 670 lz4sd->prefixEnd = (BYTE *)dest + originalSize; 671 } 672 return result; 673 } 674 675 int LZ4_decompress_safe_usingDict(const char *source, char *dest, 676 int compressedSize, int maxOutputSize, 677 const char *dictStart, int dictSize) 678 { 679 if (dictSize == 0) 680 return LZ4_decompress_safe(source, dest, 681 compressedSize, maxOutputSize); 682 if (dictStart+dictSize == dest) { 683 if (dictSize >= 64 * KB - 1) 684 return LZ4_decompress_safe_withPrefix64k(source, dest, 685 compressedSize, maxOutputSize); 686 return LZ4_decompress_safe_withSmallPrefix(source, dest, 687 compressedSize, maxOutputSize, dictSize); 688 } 689 return LZ4_decompress_safe_forceExtDict(source, dest, 690 compressedSize, maxOutputSize, dictStart, dictSize); 691 } 692 693 int LZ4_decompress_fast_usingDict(const char *source, char *dest, 694 int originalSize, 695 const char *dictStart, int dictSize) 696 { 697 if (dictSize == 0 || dictStart + dictSize == dest) 698 return LZ4_decompress_fast(source, dest, originalSize); 699 700 return LZ4_decompress_fast_extDict(source, dest, originalSize, 701 dictStart, dictSize); 702 } 703 704 #ifndef STATIC 705 EXPORT_SYMBOL(LZ4_decompress_safe); 706 EXPORT_SYMBOL(LZ4_decompress_safe_partial); 707 EXPORT_SYMBOL(LZ4_decompress_fast); 708 EXPORT_SYMBOL(LZ4_setStreamDecode); 709 EXPORT_SYMBOL(LZ4_decompress_safe_continue); 710 EXPORT_SYMBOL(LZ4_decompress_fast_continue); 711 EXPORT_SYMBOL(LZ4_decompress_safe_usingDict); 712 EXPORT_SYMBOL(LZ4_decompress_fast_usingDict); 713 714 MODULE_LICENSE("Dual BSD/GPL"); 715 MODULE_DESCRIPTION("LZ4 decompressor"); 716 #endif 717