This source file includes following definitions.
- LZ4_decompress_generic
- LZ4_decompress_safe
- LZ4_decompress_safe_partial
- LZ4_decompress_fast
- LZ4_decompress_safe_withPrefix64k
- LZ4_decompress_safe_withSmallPrefix
- LZ4_decompress_safe_forceExtDict
- LZ4_decompress_fast_extDict
- LZ4_decompress_safe_doubleDict
- LZ4_decompress_fast_doubleDict
- LZ4_setStreamDecode
- LZ4_decompress_safe_continue
- LZ4_decompress_fast_continue
- LZ4_decompress_safe_usingDict
- LZ4_decompress_fast_usingDict
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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
45
46
47 #define DEBUGLOG(l, ...) {}
48
49 #ifndef assert
50 #define assert(condition) ((void)0)
51 #endif
52
53
54
55
56
57
58
59
60 static FORCE_INLINE int LZ4_decompress_generic(
61 const char * const src,
62 char * const dst,
63 int srcSize,
64
65
66
67
68 int outputSize,
69
70 endCondition_directive endOnInput,
71
72 earlyEnd_directive partialDecoding,
73
74 dict_directive dict,
75
76 const BYTE * const lowPrefix,
77
78 const BYTE * const dictStart,
79
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
98 const BYTE *const shortiend = iend -
99 (endOnInput ? 14 : 8) - 2 ;
100 const BYTE *const shortoend = oend -
101 (endOnInput ? 14 : 8) - 18 ;
102
103 DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
104 srcSize, outputSize);
105
106
107 assert(lowPrefix <= op);
108 assert(src != NULL);
109
110
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
121 while (1) {
122 size_t length;
123 const BYTE *match;
124 size_t offset;
125
126
127 unsigned int const token = *ip++;
128 length = token>>ML_BITS;
129
130
131 assert(!endOnInput || ip <= iend);
132
133
134
135
136
137
138
139
140
141
142
143
144
145 if ((endOnInput ? length != RUN_MASK : length <= 8)
146
147
148
149
150 && likely((endOnInput ? ip < shortiend : 1) &
151 (op <= shortoend))) {
152
153 memcpy(op, ip, endOnInput ? 16 : 8);
154 op += length; ip += length;
155
156
157
158
159
160
161 length = token & ML_MASK;
162 offset = LZ4_readLE16(ip);
163 ip += 2;
164 match = op - offset;
165 assert(match <= op);
166
167
168 if ((length != ML_MASK) &&
169 (offset >= 8) &&
170 (dict == withPrefix64k || match >= lowPrefix)) {
171
172 memcpy(op + 0, match + 0, 8);
173 memcpy(op + 8, match + 8, 8);
174 memcpy(op + 16, match + 16, 2);
175 op += length + MINMATCH;
176
177 continue;
178 }
179
180
181
182
183
184
185 goto _copy_match;
186 }
187
188
189 if (length == RUN_MASK) {
190 unsigned int s;
191
192 if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
193
194 goto _output_error;
195 }
196 do {
197 s = *ip++;
198 length += s;
199 } while (likely(endOnInput
200 ? ip < iend - RUN_MASK
201 : 1) & (s == 255));
202
203 if ((safeDecode)
204 && unlikely((uptrval)(op) +
205 length < (uptrval)(op))) {
206
207 goto _output_error;
208 }
209 if ((safeDecode)
210 && unlikely((uptrval)(ip) +
211 length < (uptrval)(ip))) {
212
213 goto _output_error;
214 }
215 }
216
217
218 cpy = op + length;
219 LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
220
221 if (((endOnInput) && ((cpy > oend - MFLIMIT)
222 || (ip + length > iend - (2 + 1 + LASTLITERALS))))
223 || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
224 if (partialDecoding) {
225 if (cpy > oend) {
226
227
228
229
230 cpy = oend;
231 length = oend - op;
232 }
233 if ((endOnInput)
234 && (ip + length > iend)) {
235
236
237
238
239
240 goto _output_error;
241 }
242 } else {
243 if ((!endOnInput)
244 && (cpy != oend)) {
245
246
247
248
249
250 goto _output_error;
251 }
252 if ((endOnInput)
253 && ((ip + length != iend)
254 || (cpy > oend))) {
255
256
257
258
259 goto _output_error;
260 }
261 }
262
263 memcpy(op, ip, length);
264 ip += length;
265 op += length;
266
267
268 if (!partialDecoding || (cpy == oend))
269 break;
270 } else {
271
272 LZ4_wildCopy(op, ip, cpy);
273 ip += length;
274 op = cpy;
275 }
276
277
278 offset = LZ4_readLE16(ip);
279 ip += 2;
280 match = op - offset;
281
282
283 length = token & ML_MASK;
284
285 _copy_match:
286 if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
287
288 goto _output_error;
289 }
290
291
292
293
294
295
296 if (!partialDecoding) {
297 assert(oend > op);
298 assert(oend - op >= 4);
299
300 LZ4_write32(op, (U32)offset);
301 }
302
303 if (length == ML_MASK) {
304 unsigned int s;
305
306 do {
307 s = *ip++;
308
309 if ((endOnInput) && (ip > iend - LASTLITERALS))
310 goto _output_error;
311
312 length += s;
313 } while (s == 255);
314
315 if ((safeDecode)
316 && unlikely(
317 (uptrval)(op) + length < (uptrval)op)) {
318
319 goto _output_error;
320 }
321 }
322
323 length += MINMATCH;
324
325
326 if ((dict == usingExtDict) && (match < lowPrefix)) {
327 if (unlikely(op + length > oend - LASTLITERALS)) {
328
329 if (!partialDecoding)
330 goto _output_error;
331 length = min(length, (size_t)(oend - op));
332 }
333
334 if (length <= (size_t)(lowPrefix - match)) {
335
336
337
338
339 memmove(op, dictEnd - (lowPrefix - match),
340 length);
341 op += length;
342 } else {
343
344
345
346
347 size_t const copySize = (size_t)(lowPrefix - match);
348 size_t const restSize = length - copySize;
349
350 memcpy(op, dictEnd - copySize, copySize);
351 op += copySize;
352 if (restSize > (size_t)(op - lowPrefix)) {
353
354 BYTE * const endOfMatch = op + restSize;
355 const BYTE *copyFrom = lowPrefix;
356
357 while (op < endOfMatch)
358 *op++ = *copyFrom++;
359 } else {
360 memcpy(op, lowPrefix, restSize);
361 op += restSize;
362 }
363 }
364 continue;
365 }
366
367
368 cpy = op + length;
369
370
371
372
373
374 assert(op <= oend);
375 if (partialDecoding &&
376 (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
377 size_t const mlen = min(length, (size_t)(oend - op));
378 const BYTE * const matchEnd = match + mlen;
379 BYTE * const copyEnd = op + mlen;
380
381 if (matchEnd > op) {
382
383 while (op < copyEnd)
384 *op++ = *match++;
385 } else {
386 memcpy(op, match, mlen);
387 }
388 op = copyEnd;
389 if (op == oend)
390 break;
391 continue;
392 }
393
394 if (unlikely(offset < 8)) {
395 op[0] = match[0];
396 op[1] = match[1];
397 op[2] = match[2];
398 op[3] = match[3];
399 match += inc32table[offset];
400 memcpy(op + 4, match, 4);
401 match -= dec64table[offset];
402 } else {
403 LZ4_copy8(op, match);
404 match += 8;
405 }
406
407 op += 8;
408
409 if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
410 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
411
412 if (cpy > oend - LASTLITERALS) {
413
414
415
416
417 goto _output_error;
418 }
419
420 if (op < oCopyLimit) {
421 LZ4_wildCopy(op, match, oCopyLimit);
422 match += oCopyLimit - op;
423 op = oCopyLimit;
424 }
425 while (op < cpy)
426 *op++ = *match++;
427 } else {
428 LZ4_copy8(op, match);
429 if (length > 16)
430 LZ4_wildCopy(op + 8, match + 8, cpy);
431 }
432 op = cpy;
433 }
434
435
436 if (endOnInput) {
437
438 return (int) (((char *)op) - dst);
439 } else {
440
441 return (int) (((const char *)ip) - src);
442 }
443
444
445 _output_error:
446 return (int) (-(((const char *)ip) - src)) - 1;
447 }
448
449 int LZ4_decompress_safe(const char *source, char *dest,
450 int compressedSize, int maxDecompressedSize)
451 {
452 return LZ4_decompress_generic(source, dest,
453 compressedSize, maxDecompressedSize,
454 endOnInputSize, decode_full_block,
455 noDict, (BYTE *)dest, NULL, 0);
456 }
457
458 int LZ4_decompress_safe_partial(const char *src, char *dst,
459 int compressedSize, int targetOutputSize, int dstCapacity)
460 {
461 dstCapacity = min(targetOutputSize, dstCapacity);
462 return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
463 endOnInputSize, partial_decode,
464 noDict, (BYTE *)dst, NULL, 0);
465 }
466
467 int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
468 {
469 return LZ4_decompress_generic(source, dest, 0, originalSize,
470 endOnOutputSize, decode_full_block,
471 withPrefix64k,
472 (BYTE *)dest - 64 * KB, NULL, 0);
473 }
474
475
476
477 int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest,
478 int compressedSize, int maxOutputSize)
479 {
480 return LZ4_decompress_generic(source, dest,
481 compressedSize, maxOutputSize,
482 endOnInputSize, decode_full_block,
483 withPrefix64k,
484 (BYTE *)dest - 64 * KB, NULL, 0);
485 }
486
487 static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest,
488 int compressedSize,
489 int maxOutputSize,
490 size_t prefixSize)
491 {
492 return LZ4_decompress_generic(source, dest,
493 compressedSize, maxOutputSize,
494 endOnInputSize, decode_full_block,
495 noDict,
496 (BYTE *)dest - prefixSize, NULL, 0);
497 }
498
499 int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
500 int compressedSize, int maxOutputSize,
501 const void *dictStart, size_t dictSize)
502 {
503 return LZ4_decompress_generic(source, dest,
504 compressedSize, maxOutputSize,
505 endOnInputSize, decode_full_block,
506 usingExtDict, (BYTE *)dest,
507 (const BYTE *)dictStart, dictSize);
508 }
509
510 static int LZ4_decompress_fast_extDict(const char *source, char *dest,
511 int originalSize,
512 const void *dictStart, size_t dictSize)
513 {
514 return LZ4_decompress_generic(source, dest,
515 0, originalSize,
516 endOnOutputSize, decode_full_block,
517 usingExtDict, (BYTE *)dest,
518 (const BYTE *)dictStart, dictSize);
519 }
520
521
522
523
524
525
526 static FORCE_INLINE
527 int LZ4_decompress_safe_doubleDict(const char *source, char *dest,
528 int compressedSize, int maxOutputSize,
529 size_t prefixSize,
530 const void *dictStart, size_t dictSize)
531 {
532 return LZ4_decompress_generic(source, dest,
533 compressedSize, maxOutputSize,
534 endOnInputSize, decode_full_block,
535 usingExtDict, (BYTE *)dest - prefixSize,
536 (const BYTE *)dictStart, dictSize);
537 }
538
539 static FORCE_INLINE
540 int LZ4_decompress_fast_doubleDict(const char *source, char *dest,
541 int originalSize, size_t prefixSize,
542 const void *dictStart, size_t dictSize)
543 {
544 return LZ4_decompress_generic(source, dest,
545 0, originalSize,
546 endOnOutputSize, decode_full_block,
547 usingExtDict, (BYTE *)dest - prefixSize,
548 (const BYTE *)dictStart, dictSize);
549 }
550
551
552
553 int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
554 const char *dictionary, int dictSize)
555 {
556 LZ4_streamDecode_t_internal *lz4sd =
557 &LZ4_streamDecode->internal_donotuse;
558
559 lz4sd->prefixSize = (size_t) dictSize;
560 lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize;
561 lz4sd->externalDict = NULL;
562 lz4sd->extDictSize = 0;
563 return 1;
564 }
565
566
567
568
569
570
571
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574
575
576 int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
577 const char *source, char *dest, int compressedSize, int maxOutputSize)
578 {
579 LZ4_streamDecode_t_internal *lz4sd =
580 &LZ4_streamDecode->internal_donotuse;
581 int result;
582
583 if (lz4sd->prefixSize == 0) {
584
585 assert(lz4sd->extDictSize == 0);
586 result = LZ4_decompress_safe(source, dest,
587 compressedSize, maxOutputSize);
588 if (result <= 0)
589 return result;
590 lz4sd->prefixSize = result;
591 lz4sd->prefixEnd = (BYTE *)dest + result;
592 } else if (lz4sd->prefixEnd == (BYTE *)dest) {
593
594 if (lz4sd->prefixSize >= 64 * KB - 1)
595 result = LZ4_decompress_safe_withPrefix64k(source, dest,
596 compressedSize, maxOutputSize);
597 else if (lz4sd->extDictSize == 0)
598 result = LZ4_decompress_safe_withSmallPrefix(source,
599 dest, compressedSize, maxOutputSize,
600 lz4sd->prefixSize);
601 else
602 result = LZ4_decompress_safe_doubleDict(source, dest,
603 compressedSize, maxOutputSize,
604 lz4sd->prefixSize,
605 lz4sd->externalDict, lz4sd->extDictSize);
606 if (result <= 0)
607 return result;
608 lz4sd->prefixSize += result;
609 lz4sd->prefixEnd += result;
610 } else {
611
612
613
614
615 lz4sd->extDictSize = lz4sd->prefixSize;
616 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
617 result = LZ4_decompress_safe_forceExtDict(source, dest,
618 compressedSize, maxOutputSize,
619 lz4sd->externalDict, lz4sd->extDictSize);
620 if (result <= 0)
621 return result;
622 lz4sd->prefixSize = result;
623 lz4sd->prefixEnd = (BYTE *)dest + result;
624 }
625
626 return result;
627 }
628
629 int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
630 const char *source, char *dest, int originalSize)
631 {
632 LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
633 int result;
634
635 if (lz4sd->prefixSize == 0) {
636 assert(lz4sd->extDictSize == 0);
637 result = LZ4_decompress_fast(source, dest, originalSize);
638 if (result <= 0)
639 return result;
640 lz4sd->prefixSize = originalSize;
641 lz4sd->prefixEnd = (BYTE *)dest + originalSize;
642 } else if (lz4sd->prefixEnd == (BYTE *)dest) {
643 if (lz4sd->prefixSize >= 64 * KB - 1 ||
644 lz4sd->extDictSize == 0)
645 result = LZ4_decompress_fast(source, dest,
646 originalSize);
647 else
648 result = LZ4_decompress_fast_doubleDict(source, dest,
649 originalSize, lz4sd->prefixSize,
650 lz4sd->externalDict, lz4sd->extDictSize);
651 if (result <= 0)
652 return result;
653 lz4sd->prefixSize += originalSize;
654 lz4sd->prefixEnd += originalSize;
655 } else {
656 lz4sd->extDictSize = lz4sd->prefixSize;
657 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
658 result = LZ4_decompress_fast_extDict(source, dest,
659 originalSize, lz4sd->externalDict, lz4sd->extDictSize);
660 if (result <= 0)
661 return result;
662 lz4sd->prefixSize = originalSize;
663 lz4sd->prefixEnd = (BYTE *)dest + originalSize;
664 }
665 return result;
666 }
667
668 int LZ4_decompress_safe_usingDict(const char *source, char *dest,
669 int compressedSize, int maxOutputSize,
670 const char *dictStart, int dictSize)
671 {
672 if (dictSize == 0)
673 return LZ4_decompress_safe(source, dest,
674 compressedSize, maxOutputSize);
675 if (dictStart+dictSize == dest) {
676 if (dictSize >= 64 * KB - 1)
677 return LZ4_decompress_safe_withPrefix64k(source, dest,
678 compressedSize, maxOutputSize);
679 return LZ4_decompress_safe_withSmallPrefix(source, dest,
680 compressedSize, maxOutputSize, dictSize);
681 }
682 return LZ4_decompress_safe_forceExtDict(source, dest,
683 compressedSize, maxOutputSize, dictStart, dictSize);
684 }
685
686 int LZ4_decompress_fast_usingDict(const char *source, char *dest,
687 int originalSize,
688 const char *dictStart, int dictSize)
689 {
690 if (dictSize == 0 || dictStart + dictSize == dest)
691 return LZ4_decompress_fast(source, dest, originalSize);
692
693 return LZ4_decompress_fast_extDict(source, dest, originalSize,
694 dictStart, dictSize);
695 }
696
697 #ifndef STATIC
698 EXPORT_SYMBOL(LZ4_decompress_safe);
699 EXPORT_SYMBOL(LZ4_decompress_safe_partial);
700 EXPORT_SYMBOL(LZ4_decompress_fast);
701 EXPORT_SYMBOL(LZ4_setStreamDecode);
702 EXPORT_SYMBOL(LZ4_decompress_safe_continue);
703 EXPORT_SYMBOL(LZ4_decompress_fast_continue);
704 EXPORT_SYMBOL(LZ4_decompress_safe_usingDict);
705 EXPORT_SYMBOL(LZ4_decompress_fast_usingDict);
706
707 MODULE_LICENSE("Dual BSD/GPL");
708 MODULE_DESCRIPTION("LZ4 decompressor");
709 #endif