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 "lz4defs.h" 37 #include <linux/init.h> 38 #include <linux/module.h> 39 #include <linux/kernel.h> 40 #include <linux/unaligned.h> 41 42 /*-***************************** 43 * Decompression functions 44 *******************************/ 45 46 #define DEBUGLOG(l, ...) {} /* disabled */ 47 48 #ifndef assert 49 #define assert(condition) ((void)0) 50 #endif 51 52 /* 53 * LZ4_decompress_generic() : 54 * This generic decompression function covers all use cases. 55 * It shall be instantiated several times, using different sets of directives. 56 * Note that it is important for performance that this function really get inlined, 57 * in order to remove useless branches during compilation optimization. 58 */ 59 static FORCE_INLINE int LZ4_decompress_generic( 60 const char * const src, 61 char * const dst, 62 int srcSize, 63 /* 64 * If endOnInput == endOnInputSize, 65 * this value is `dstCapacity` 66 */ 67 int outputSize, 68 /* endOnOutputSize, endOnInputSize */ 69 endCondition_directive endOnInput, 70 /* full, partial */ 71 earlyEnd_directive partialDecoding, 72 /* noDict, withPrefix64k, usingExtDict */ 73 dict_directive dict, 74 /* always <= dst, == dst when no prefix */ 75 const BYTE * const lowPrefix, 76 /* only if dict == usingExtDict */ 77 const BYTE * const dictStart, 78 /* note : = 0 if noDict */ 79 const size_t dictSize 80 ) 81 { 82 const BYTE *ip = (const BYTE *) src; 83 const BYTE * const iend = ip + srcSize; 84 85 BYTE *op = (BYTE *) dst; 86 BYTE * const oend = op + outputSize; 87 BYTE *cpy; 88 89 const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize; 90 static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4}; 91 static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3}; 92 93 const int safeDecode = (endOnInput == endOnInputSize); 94 const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB))); 95 96 /* Set up the "end" pointers for the shortcut. */ 97 const BYTE *const shortiend = iend - 98 (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/; 99 const BYTE *const shortoend = oend - 100 (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/; 101 102 DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__, 103 srcSize, outputSize); 104 105 /* Special cases */ 106 assert(lowPrefix <= op); 107 assert(src != NULL); 108 109 /* Empty output buffer */ 110 if ((endOnInput) && (unlikely(outputSize == 0))) 111 return ((srcSize == 1) && (*ip == 0)) ? 0 : -1; 112 113 if ((!endOnInput) && (unlikely(outputSize == 0))) 114 return (*ip == 0 ? 1 : -1); 115 116 if ((endOnInput) && unlikely(srcSize == 0)) 117 return -1; 118 119 /* Main Loop : decode sequences */ 120 while (1) { 121 size_t length; 122 const BYTE *match; 123 size_t offset; 124 125 /* get literal length */ 126 unsigned int const token = *ip++; 127 length = token>>ML_BITS; 128 129 /* ip < iend before the increment */ 130 assert(!endOnInput || ip <= iend); 131 132 /* 133 * A two-stage shortcut for the most common case: 134 * 1) If the literal length is 0..14, and there is enough 135 * space, enter the shortcut and copy 16 bytes on behalf 136 * of the literals (in the fast mode, only 8 bytes can be 137 * safely copied this way). 138 * 2) Further if the match length is 4..18, copy 18 bytes 139 * in a similar manner; but we ensure that there's enough 140 * space in the output for those 18 bytes earlier, upon 141 * entering the shortcut (in other words, there is a 142 * combined check for both stages). 143 * 144 * The & in the likely() below is intentionally not && so that 145 * some compilers can produce better parallelized runtime code 146 */ 147 if ((endOnInput ? length != RUN_MASK : length <= 8) 148 /* 149 * strictly "less than" on input, to re-enter 150 * the loop with at least one byte 151 */ 152 && likely((endOnInput ? ip < shortiend : 1) & 153 (op <= shortoend))) { 154 /* Copy the literals */ 155 LZ4_memcpy(op, ip, endOnInput ? 16 : 8); 156 op += length; ip += length; 157 158 /* 159 * The second stage: 160 * prepare for match copying, decode full info. 161 * If it doesn't work out, the info won't be wasted. 162 */ 163 length = token & ML_MASK; /* match length */ 164 offset = LZ4_readLE16(ip); 165 ip += 2; 166 match = op - offset; 167 assert(match <= op); /* check overflow */ 168 169 /* Do not deal with overlapping matches. */ 170 if ((length != ML_MASK) && 171 (offset >= 8) && 172 (dict == withPrefix64k || match >= lowPrefix)) { 173 /* Copy the match. */ 174 LZ4_memcpy(op + 0, match + 0, 8); 175 LZ4_memcpy(op + 8, match + 8, 8); 176 LZ4_memcpy(op + 16, match + 16, 2); 177 op += length + MINMATCH; 178 /* Both stages worked, load the next token. */ 179 continue; 180 } 181 182 /* 183 * The second stage didn't work out, but the info 184 * is ready. Propel it right to the point of match 185 * copying. 186 */ 187 goto _copy_match; 188 } 189 190 /* decode literal length */ 191 if (length == RUN_MASK) { 192 unsigned int s; 193 194 if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) { 195 /* overflow detection */ 196 goto _output_error; 197 } 198 do { 199 s = *ip++; 200 length += s; 201 } while (likely(endOnInput 202 ? ip < iend - RUN_MASK 203 : 1) & (s == 255)); 204 205 if ((safeDecode) 206 && unlikely((uptrval)(op) + 207 length < (uptrval)(op))) { 208 /* overflow detection */ 209 goto _output_error; 210 } 211 if ((safeDecode) 212 && unlikely((uptrval)(ip) + 213 length < (uptrval)(ip))) { 214 /* overflow detection */ 215 goto _output_error; 216 } 217 } 218 219 /* copy literals */ 220 cpy = op + length; 221 LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH); 222 223 if (((endOnInput) && ((cpy > oend - MFLIMIT) 224 || (ip + length > iend - (2 + 1 + LASTLITERALS)))) 225 || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) { 226 if (partialDecoding) { 227 if (cpy > oend) { 228 /* 229 * Partial decoding : 230 * stop in the middle of literal segment 231 */ 232 cpy = oend; 233 length = oend - op; 234 } 235 if ((endOnInput) 236 && (ip + length > iend)) { 237 /* 238 * Error : 239 * read attempt beyond 240 * end of input buffer 241 */ 242 goto _output_error; 243 } 244 } else { 245 if ((!endOnInput) 246 && (cpy != oend)) { 247 /* 248 * Error : 249 * block decoding must 250 * stop exactly there 251 */ 252 goto _output_error; 253 } 254 if ((endOnInput) 255 && ((ip + length != iend) 256 || (cpy > oend))) { 257 /* 258 * Error : 259 * input must be consumed 260 */ 261 goto _output_error; 262 } 263 } 264 265 /* 266 * supports overlapping memory regions; only matters 267 * for in-place decompression scenarios 268 */ 269 LZ4_memmove(op, ip, length); 270 ip += length; 271 op += length; 272 273 /* Necessarily EOF when !partialDecoding. 274 * When partialDecoding, it is EOF if we've either 275 * filled the output buffer or 276 * can't proceed with reading an offset for following match. 277 */ 278 if (!partialDecoding || (cpy == oend) || (ip >= (iend - 2))) 279 break; 280 } else { 281 /* may overwrite up to WILDCOPYLENGTH beyond cpy */ 282 LZ4_wildCopy(op, ip, cpy); 283 ip += length; 284 op = cpy; 285 } 286 287 /* get offset */ 288 offset = LZ4_readLE16(ip); 289 ip += 2; 290 match = op - offset; 291 292 /* get matchlength */ 293 length = token & ML_MASK; 294 295 _copy_match: 296 if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { 297 /* Error : offset outside buffers */ 298 goto _output_error; 299 } 300 301 /* costs ~1%; silence an msan warning when offset == 0 */ 302 /* 303 * note : when partialDecoding, there is no guarantee that 304 * at least 4 bytes remain available in output buffer 305 */ 306 if (!partialDecoding) { 307 assert(oend > op); 308 assert(oend - op >= 4); 309 310 LZ4_write32(op, (U32)offset); 311 } 312 313 if (length == ML_MASK) { 314 unsigned int s; 315 316 do { 317 s = *ip++; 318 319 if ((endOnInput) && (ip > iend - LASTLITERALS)) 320 goto _output_error; 321 322 length += s; 323 } while (s == 255); 324 325 if ((safeDecode) 326 && unlikely( 327 (uptrval)(op) + length < (uptrval)op)) { 328 /* overflow detection */ 329 goto _output_error; 330 } 331 } 332 333 length += MINMATCH; 334 335 /* match starting within external dictionary */ 336 if ((dict == usingExtDict) && (match < lowPrefix)) { 337 if (unlikely(op + length > oend - LASTLITERALS)) { 338 /* doesn't respect parsing restriction */ 339 if (!partialDecoding) 340 goto _output_error; 341 length = min(length, (size_t)(oend - op)); 342 } 343 344 if (length <= (size_t)(lowPrefix - match)) { 345 /* 346 * match fits entirely within external 347 * dictionary : just copy 348 */ 349 memmove(op, dictEnd - (lowPrefix - match), 350 length); 351 op += length; 352 } else { 353 /* 354 * match stretches into both external 355 * dictionary and current block 356 */ 357 size_t const copySize = (size_t)(lowPrefix - match); 358 size_t const restSize = length - copySize; 359 360 LZ4_memcpy(op, dictEnd - copySize, copySize); 361 op += copySize; 362 if (restSize > (size_t)(op - lowPrefix)) { 363 /* overlap copy */ 364 BYTE * const endOfMatch = op + restSize; 365 const BYTE *copyFrom = lowPrefix; 366 367 while (op < endOfMatch) 368 *op++ = *copyFrom++; 369 } else { 370 LZ4_memcpy(op, lowPrefix, restSize); 371 op += restSize; 372 } 373 } 374 continue; 375 } 376 377 /* copy match within block */ 378 cpy = op + length; 379 380 /* 381 * partialDecoding : 382 * may not respect endBlock parsing restrictions 383 */ 384 assert(op <= oend); 385 if (partialDecoding && 386 (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 387 size_t const mlen = min(length, (size_t)(oend - op)); 388 const BYTE * const matchEnd = match + mlen; 389 BYTE * const copyEnd = op + mlen; 390 391 if (matchEnd > op) { 392 /* overlap copy */ 393 while (op < copyEnd) 394 *op++ = *match++; 395 } else { 396 LZ4_memcpy(op, match, mlen); 397 } 398 op = copyEnd; 399 if (op == oend) 400 break; 401 continue; 402 } 403 404 if (unlikely(offset < 8)) { 405 op[0] = match[0]; 406 op[1] = match[1]; 407 op[2] = match[2]; 408 op[3] = match[3]; 409 match += inc32table[offset]; 410 LZ4_memcpy(op + 4, match, 4); 411 match -= dec64table[offset]; 412 } else { 413 LZ4_copy8(op, match); 414 match += 8; 415 } 416 417 op += 8; 418 419 if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) { 420 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1); 421 422 if (cpy > oend - LASTLITERALS) { 423 /* 424 * Error : last LASTLITERALS bytes 425 * must be literals (uncompressed) 426 */ 427 goto _output_error; 428 } 429 430 if (op < oCopyLimit) { 431 LZ4_wildCopy(op, match, oCopyLimit); 432 match += oCopyLimit - op; 433 op = oCopyLimit; 434 } 435 while (op < cpy) 436 *op++ = *match++; 437 } else { 438 LZ4_copy8(op, match); 439 if (length > 16) 440 LZ4_wildCopy(op + 8, match + 8, cpy); 441 } 442 op = cpy; /* wildcopy correction */ 443 } 444 445 /* end of decoding */ 446 if (endOnInput) { 447 /* Nb of output bytes decoded */ 448 return (int) (((char *)op) - dst); 449 } else { 450 /* Nb of input bytes read */ 451 return (int) (((const char *)ip) - src); 452 } 453 454 /* Overflow error detected */ 455 _output_error: 456 return (int) (-(((const char *)ip) - src)) - 1; 457 } 458 459 int LZ4_decompress_safe(const char *source, char *dest, 460 int compressedSize, int maxDecompressedSize) 461 { 462 return LZ4_decompress_generic(source, dest, 463 compressedSize, maxDecompressedSize, 464 endOnInputSize, decode_full_block, 465 noDict, (BYTE *)dest, NULL, 0); 466 } 467 468 int LZ4_decompress_safe_partial(const char *src, char *dst, 469 int compressedSize, int targetOutputSize, int dstCapacity) 470 { 471 dstCapacity = min(targetOutputSize, dstCapacity); 472 return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity, 473 endOnInputSize, partial_decode, 474 noDict, (BYTE *)dst, NULL, 0); 475 } 476 477 int LZ4_decompress_fast(const char *source, char *dest, int originalSize) 478 { 479 return LZ4_decompress_generic(source, dest, 0, originalSize, 480 endOnOutputSize, decode_full_block, 481 withPrefix64k, 482 (BYTE *)dest - 64 * KB, NULL, 0); 483 } 484 485 /* ===== Instantiate a few more decoding cases, used more than once. ===== */ 486 487 static int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest, 488 int compressedSize, int maxOutputSize) 489 { 490 return LZ4_decompress_generic(source, dest, 491 compressedSize, maxOutputSize, 492 endOnInputSize, decode_full_block, 493 withPrefix64k, 494 (BYTE *)dest - 64 * KB, NULL, 0); 495 } 496 497 static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest, 498 int compressedSize, 499 int maxOutputSize, 500 size_t prefixSize) 501 { 502 return LZ4_decompress_generic(source, dest, 503 compressedSize, maxOutputSize, 504 endOnInputSize, decode_full_block, 505 noDict, 506 (BYTE *)dest - prefixSize, NULL, 0); 507 } 508 509 static int LZ4_decompress_safe_forceExtDict(const char *source, char *dest, 510 int compressedSize, int maxOutputSize, 511 const void *dictStart, size_t dictSize) 512 { 513 return LZ4_decompress_generic(source, dest, 514 compressedSize, maxOutputSize, 515 endOnInputSize, decode_full_block, 516 usingExtDict, (BYTE *)dest, 517 (const BYTE *)dictStart, dictSize); 518 } 519 520 static int LZ4_decompress_fast_extDict(const char *source, char *dest, 521 int originalSize, 522 const void *dictStart, size_t dictSize) 523 { 524 return LZ4_decompress_generic(source, dest, 525 0, originalSize, 526 endOnOutputSize, decode_full_block, 527 usingExtDict, (BYTE *)dest, 528 (const BYTE *)dictStart, dictSize); 529 } 530 531 /* 532 * The "double dictionary" mode, for use with e.g. ring buffers: the first part 533 * of the dictionary is passed as prefix, and the second via dictStart + dictSize. 534 * These routines are used only once, in LZ4_decompress_*_continue(). 535 */ 536 static FORCE_INLINE 537 int LZ4_decompress_safe_doubleDict(const char *source, char *dest, 538 int compressedSize, int maxOutputSize, 539 size_t prefixSize, 540 const void *dictStart, size_t dictSize) 541 { 542 return LZ4_decompress_generic(source, dest, 543 compressedSize, maxOutputSize, 544 endOnInputSize, decode_full_block, 545 usingExtDict, (BYTE *)dest - prefixSize, 546 (const BYTE *)dictStart, dictSize); 547 } 548 549 static FORCE_INLINE 550 int LZ4_decompress_fast_doubleDict(const char *source, char *dest, 551 int originalSize, size_t prefixSize, 552 const void *dictStart, size_t dictSize) 553 { 554 return LZ4_decompress_generic(source, dest, 555 0, originalSize, 556 endOnOutputSize, decode_full_block, 557 usingExtDict, (BYTE *)dest - prefixSize, 558 (const BYTE *)dictStart, dictSize); 559 } 560 561 /* ===== streaming decompression functions ===== */ 562 563 int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode, 564 const char *dictionary, int dictSize) 565 { 566 LZ4_streamDecode_t_internal *lz4sd = 567 &LZ4_streamDecode->internal_donotuse; 568 569 lz4sd->prefixSize = (size_t) dictSize; 570 lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize; 571 lz4sd->externalDict = NULL; 572 lz4sd->extDictSize = 0; 573 return 1; 574 } 575 576 /* 577 * *_continue() : 578 * These decoding functions allow decompression of multiple blocks 579 * in "streaming" mode. 580 * Previously decoded blocks must still be available at the memory 581 * position where they were decoded. 582 * If it's not possible, save the relevant part of 583 * decoded data into a safe buffer, 584 * and indicate where it stands using LZ4_setStreamDecode() 585 */ 586 int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode, 587 const char *source, char *dest, int compressedSize, int maxOutputSize) 588 { 589 LZ4_streamDecode_t_internal *lz4sd = 590 &LZ4_streamDecode->internal_donotuse; 591 int result; 592 593 if (lz4sd->prefixSize == 0) { 594 /* The first call, no dictionary yet. */ 595 assert(lz4sd->extDictSize == 0); 596 result = LZ4_decompress_safe(source, dest, 597 compressedSize, maxOutputSize); 598 if (result <= 0) 599 return result; 600 lz4sd->prefixSize = result; 601 lz4sd->prefixEnd = (BYTE *)dest + result; 602 } else if (lz4sd->prefixEnd == (BYTE *)dest) { 603 /* They're rolling the current segment. */ 604 if (lz4sd->prefixSize >= 64 * KB - 1) 605 result = LZ4_decompress_safe_withPrefix64k(source, dest, 606 compressedSize, maxOutputSize); 607 else if (lz4sd->extDictSize == 0) 608 result = LZ4_decompress_safe_withSmallPrefix(source, 609 dest, compressedSize, maxOutputSize, 610 lz4sd->prefixSize); 611 else 612 result = LZ4_decompress_safe_doubleDict(source, dest, 613 compressedSize, maxOutputSize, 614 lz4sd->prefixSize, 615 lz4sd->externalDict, lz4sd->extDictSize); 616 if (result <= 0) 617 return result; 618 lz4sd->prefixSize += result; 619 lz4sd->prefixEnd += result; 620 } else { 621 /* 622 * The buffer wraps around, or they're 623 * switching to another buffer. 624 */ 625 lz4sd->extDictSize = lz4sd->prefixSize; 626 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; 627 result = LZ4_decompress_safe_forceExtDict(source, dest, 628 compressedSize, maxOutputSize, 629 lz4sd->externalDict, lz4sd->extDictSize); 630 if (result <= 0) 631 return result; 632 lz4sd->prefixSize = result; 633 lz4sd->prefixEnd = (BYTE *)dest + result; 634 } 635 636 return result; 637 } 638 639 int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode, 640 const char *source, char *dest, int originalSize) 641 { 642 LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse; 643 int result; 644 645 if (lz4sd->prefixSize == 0) { 646 assert(lz4sd->extDictSize == 0); 647 result = LZ4_decompress_fast(source, dest, originalSize); 648 if (result <= 0) 649 return result; 650 lz4sd->prefixSize = originalSize; 651 lz4sd->prefixEnd = (BYTE *)dest + originalSize; 652 } else if (lz4sd->prefixEnd == (BYTE *)dest) { 653 if (lz4sd->prefixSize >= 64 * KB - 1 || 654 lz4sd->extDictSize == 0) 655 result = LZ4_decompress_fast(source, dest, 656 originalSize); 657 else 658 result = LZ4_decompress_fast_doubleDict(source, dest, 659 originalSize, lz4sd->prefixSize, 660 lz4sd->externalDict, lz4sd->extDictSize); 661 if (result <= 0) 662 return result; 663 lz4sd->prefixSize += originalSize; 664 lz4sd->prefixEnd += originalSize; 665 } else { 666 lz4sd->extDictSize = lz4sd->prefixSize; 667 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; 668 result = LZ4_decompress_fast_extDict(source, dest, 669 originalSize, lz4sd->externalDict, lz4sd->extDictSize); 670 if (result <= 0) 671 return result; 672 lz4sd->prefixSize = originalSize; 673 lz4sd->prefixEnd = (BYTE *)dest + originalSize; 674 } 675 return result; 676 } 677 678 int LZ4_decompress_safe_usingDict(const char *source, char *dest, 679 int compressedSize, int maxOutputSize, 680 const char *dictStart, int dictSize) 681 { 682 if (dictSize == 0) 683 return LZ4_decompress_safe(source, dest, 684 compressedSize, maxOutputSize); 685 if (dictStart+dictSize == dest) { 686 if (dictSize >= 64 * KB - 1) 687 return LZ4_decompress_safe_withPrefix64k(source, dest, 688 compressedSize, maxOutputSize); 689 return LZ4_decompress_safe_withSmallPrefix(source, dest, 690 compressedSize, maxOutputSize, dictSize); 691 } 692 return LZ4_decompress_safe_forceExtDict(source, dest, 693 compressedSize, maxOutputSize, dictStart, dictSize); 694 } 695 696 int LZ4_decompress_fast_usingDict(const char *source, char *dest, 697 int originalSize, 698 const char *dictStart, int dictSize) 699 { 700 if (dictSize == 0 || dictStart + dictSize == dest) 701 return LZ4_decompress_fast(source, dest, originalSize); 702 703 return LZ4_decompress_fast_extDict(source, dest, originalSize, 704 dictStart, dictSize); 705 } 706 707 #ifndef STATIC 708 EXPORT_SYMBOL(LZ4_decompress_safe); 709 EXPORT_SYMBOL(LZ4_decompress_safe_partial); 710 EXPORT_SYMBOL(LZ4_decompress_fast); 711 EXPORT_SYMBOL(LZ4_setStreamDecode); 712 EXPORT_SYMBOL(LZ4_decompress_safe_continue); 713 EXPORT_SYMBOL(LZ4_decompress_fast_continue); 714 EXPORT_SYMBOL(LZ4_decompress_safe_usingDict); 715 EXPORT_SYMBOL(LZ4_decompress_fast_usingDict); 716 717 MODULE_LICENSE("Dual BSD/GPL"); 718 MODULE_DESCRIPTION("LZ4 decompressor"); 719 #endif 720