hc
2023-12-11 d2ccde1c8e90d38cee87a1b0309ad2827f3fd30d
kernel/lib/lz4/lz4_decompress.c
....@@ -43,30 +43,36 @@
4343 /*-*****************************
4444 * Decompression functions
4545 *******************************/
46
-/* LZ4_decompress_generic() :
47
- * This generic decompression function cover all use cases.
48
- * It shall be instantiated several times, using different sets of directives
49
- * Note that it is important this generic function is really inlined,
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,
5058 * in order to remove useless branches during compilation optimization.
5159 */
5260 static FORCE_INLINE int LZ4_decompress_generic(
53
- const char * const source,
54
- char * const dest,
55
- int inputSize,
61
+ const char * const src,
62
+ char * const dst,
63
+ int srcSize,
5664 /*
5765 * If endOnInput == endOnInputSize,
58
- * this value is the max size of Output Buffer.
66
+ * this value is `dstCapacity`
5967 */
6068 int outputSize,
6169 /* endOnOutputSize, endOnInputSize */
62
- int endOnInput,
70
+ endCondition_directive endOnInput,
6371 /* full, partial */
64
- int partialDecoding,
65
- /* only used if partialDecoding == partial */
66
- int targetOutputSize,
72
+ earlyEnd_directive partialDecoding,
6773 /* noDict, withPrefix64k, usingExtDict */
68
- int dict,
69
- /* == dest when no prefix */
74
+ dict_directive dict,
75
+ /* always <= dst, == dst when no prefix */
7076 const BYTE * const lowPrefix,
7177 /* only if dict == usingExtDict */
7278 const BYTE * const dictStart,
....@@ -74,34 +80,42 @@
7480 const size_t dictSize
7581 )
7682 {
77
- /* Local Variables */
78
- const BYTE *ip = (const BYTE *) source;
79
- const BYTE * const iend = ip + inputSize;
83
+ const BYTE *ip = (const BYTE *) src;
84
+ const BYTE * const iend = ip + srcSize;
8085
81
- BYTE *op = (BYTE *) dest;
86
+ BYTE *op = (BYTE *) dst;
8287 BYTE * const oend = op + outputSize;
8388 BYTE *cpy;
84
- BYTE *oexit = op + targetOutputSize;
85
- const BYTE * const lowLimit = lowPrefix - dictSize;
8689
8790 const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
88
- static const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };
89
- static const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
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};
9093
9194 const int safeDecode = (endOnInput == endOnInputSize);
9295 const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
9396
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
+
94106 /* Special cases */
95
- /* targetOutputSize too high => decode everything */
96
- if ((partialDecoding) && (oexit > oend - MFLIMIT))
97
- oexit = oend - MFLIMIT;
107
+ assert(lowPrefix <= op);
108
+ assert(src != NULL);
98109
99110 /* Empty output buffer */
100111 if ((endOnInput) && (unlikely(outputSize == 0)))
101
- return ((inputSize == 1) && (*ip == 0)) ? 0 : -1;
112
+ return ((srcSize == 1) && (*ip == 0)) ? 0 : -1;
102113
103114 if ((!endOnInput) && (unlikely(outputSize == 0)))
104115 return (*ip == 0 ? 1 : -1);
116
+
117
+ if ((endOnInput) && unlikely(srcSize == 0))
118
+ return -1;
105119
106120 /* Main Loop : decode sequences */
107121 while (1) {
....@@ -111,12 +125,77 @@
111125
112126 /* get literal length */
113127 unsigned int const token = *ip++;
114
-
115128 length = token>>ML_BITS;
116129
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 */
117192 if (length == RUN_MASK) {
118193 unsigned int s;
119194
195
+ if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
196
+ /* overflow detection */
197
+ goto _output_error;
198
+ }
120199 do {
121200 s = *ip++;
122201 length += s;
....@@ -125,14 +204,14 @@
125204 : 1) & (s == 255));
126205
127206 if ((safeDecode)
128
- && unlikely(
129
- (size_t)(op + length) < (size_t)(op))) {
207
+ && unlikely((uptrval)(op) +
208
+ length < (uptrval)(op))) {
130209 /* overflow detection */
131210 goto _output_error;
132211 }
133212 if ((safeDecode)
134
- && unlikely(
135
- (size_t)(ip + length) < (size_t)(ip))) {
213
+ && unlikely((uptrval)(ip) +
214
+ length < (uptrval)(ip))) {
136215 /* overflow detection */
137216 goto _output_error;
138217 }
....@@ -140,16 +219,19 @@
140219
141220 /* copy literals */
142221 cpy = op + length;
143
- if (((endOnInput) && ((cpy > (partialDecoding ? oexit : oend - MFLIMIT))
222
+ LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
223
+
224
+ if (((endOnInput) && ((cpy > oend - MFLIMIT)
144225 || (ip + length > iend - (2 + 1 + LASTLITERALS))))
145226 || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
146227 if (partialDecoding) {
147228 if (cpy > oend) {
148229 /*
149
- * Error :
150
- * write attempt beyond end of output buffer
230
+ * Partial decoding :
231
+ * stop in the middle of literal segment
151232 */
152
- goto _output_error;
233
+ cpy = oend;
234
+ length = oend - op;
153235 }
154236 if ((endOnInput)
155237 && (ip + length > iend)) {
....@@ -181,32 +263,54 @@
181263 }
182264 }
183265
184
- memcpy(op, ip, length);
266
+ /*
267
+ * supports overlapping memory regions; only matters
268
+ * for in-place decompression scenarios
269
+ */
270
+ LZ4_memmove(op, ip, length);
185271 ip += length;
186272 op += length;
187
- /* Necessarily EOF, due to parsing restrictions */
188
- break;
189
- }
190273
191
- LZ4_wildCopy(op, ip, cpy);
192
- ip += length;
193
- op = cpy;
274
+ /* Necessarily EOF when !partialDecoding.
275
+ * When partialDecoding, it is EOF if we've either
276
+ * filled the output buffer or
277
+ * can't proceed with reading an offset for following match.
278
+ */
279
+ if (!partialDecoding || (cpy == oend) || (ip >= (iend - 2)))
280
+ break;
281
+ } else {
282
+ /* may overwrite up to WILDCOPYLENGTH beyond cpy */
283
+ LZ4_wildCopy(op, ip, cpy);
284
+ ip += length;
285
+ op = cpy;
286
+ }
194287
195288 /* get offset */
196289 offset = LZ4_readLE16(ip);
197290 ip += 2;
198291 match = op - offset;
199292
200
- if ((checkOffset) && (unlikely(match < lowLimit))) {
293
+ /* get matchlength */
294
+ length = token & ML_MASK;
295
+
296
+_copy_match:
297
+ if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
201298 /* Error : offset outside buffers */
202299 goto _output_error;
203300 }
204301
205302 /* costs ~1%; silence an msan warning when offset == 0 */
206
- LZ4_write32(op, (U32)offset);
303
+ /*
304
+ * note : when partialDecoding, there is no guarantee that
305
+ * at least 4 bytes remain available in output buffer
306
+ */
307
+ if (!partialDecoding) {
308
+ assert(oend > op);
309
+ assert(oend - op >= 4);
207310
208
- /* get matchlength */
209
- length = token & ML_MASK;
311
+ LZ4_write32(op, (U32)offset);
312
+ }
313
+
210314 if (length == ML_MASK) {
211315 unsigned int s;
212316
....@@ -221,7 +325,7 @@
221325
222326 if ((safeDecode)
223327 && unlikely(
224
- (size_t)(op + length) < (size_t)op)) {
328
+ (uptrval)(op) + length < (uptrval)op)) {
225329 /* overflow detection */
226330 goto _output_error;
227331 }
....@@ -229,32 +333,33 @@
229333
230334 length += MINMATCH;
231335
232
- /* check external dictionary */
336
+ /* match starting within external dictionary */
233337 if ((dict == usingExtDict) && (match < lowPrefix)) {
234338 if (unlikely(op + length > oend - LASTLITERALS)) {
235339 /* doesn't respect parsing restriction */
236
- goto _output_error;
340
+ if (!partialDecoding)
341
+ goto _output_error;
342
+ length = min(length, (size_t)(oend - op));
237343 }
238344
239345 if (length <= (size_t)(lowPrefix - match)) {
240346 /*
241
- * match can be copied as a single segment
242
- * from external dictionary
347
+ * match fits entirely within external
348
+ * dictionary : just copy
243349 */
244350 memmove(op, dictEnd - (lowPrefix - match),
245351 length);
246352 op += length;
247353 } else {
248354 /*
249
- * match encompass external
355
+ * match stretches into both external
250356 * dictionary and current block
251357 */
252358 size_t const copySize = (size_t)(lowPrefix - match);
253359 size_t const restSize = length - copySize;
254360
255
- memcpy(op, dictEnd - copySize, copySize);
361
+ LZ4_memcpy(op, dictEnd - copySize, copySize);
256362 op += copySize;
257
-
258363 if (restSize > (size_t)(op - lowPrefix)) {
259364 /* overlap copy */
260365 BYTE * const endOfMatch = op + restSize;
....@@ -263,27 +368,48 @@
263368 while (op < endOfMatch)
264369 *op++ = *copyFrom++;
265370 } else {
266
- memcpy(op, lowPrefix, restSize);
371
+ LZ4_memcpy(op, lowPrefix, restSize);
267372 op += restSize;
268373 }
269374 }
270
-
271375 continue;
272376 }
273377
274378 /* copy match within block */
275379 cpy = op + length;
276380
277
- if (unlikely(offset < 8)) {
278
- const int dec64 = dec64table[offset];
381
+ /*
382
+ * partialDecoding :
383
+ * may not respect endBlock parsing restrictions
384
+ */
385
+ assert(op <= oend);
386
+ if (partialDecoding &&
387
+ (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
388
+ size_t const mlen = min(length, (size_t)(oend - op));
389
+ const BYTE * const matchEnd = match + mlen;
390
+ BYTE * const copyEnd = op + mlen;
279391
392
+ if (matchEnd > op) {
393
+ /* overlap copy */
394
+ while (op < copyEnd)
395
+ *op++ = *match++;
396
+ } else {
397
+ LZ4_memcpy(op, match, mlen);
398
+ }
399
+ op = copyEnd;
400
+ if (op == oend)
401
+ break;
402
+ continue;
403
+ }
404
+
405
+ if (unlikely(offset < 8)) {
280406 op[0] = match[0];
281407 op[1] = match[1];
282408 op[2] = match[2];
283409 op[3] = match[3];
284
- match += dec32table[offset];
285
- memcpy(op + 4, match, 4);
286
- match -= dec64;
410
+ match += inc32table[offset];
411
+ LZ4_memcpy(op + 4, match, 4);
412
+ match -= dec64table[offset];
287413 } else {
288414 LZ4_copy8(op, match);
289415 match += 8;
....@@ -291,7 +417,7 @@
291417
292418 op += 8;
293419
294
- if (unlikely(cpy > oend - 12)) {
420
+ if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
295421 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
296422
297423 if (cpy > oend - LASTLITERALS) {
....@@ -307,60 +433,139 @@
307433 match += oCopyLimit - op;
308434 op = oCopyLimit;
309435 }
310
-
311436 while (op < cpy)
312437 *op++ = *match++;
313438 } else {
314439 LZ4_copy8(op, match);
315
-
316440 if (length > 16)
317441 LZ4_wildCopy(op + 8, match + 8, cpy);
318442 }
319
-
320
- op = cpy; /* correction */
443
+ op = cpy; /* wildcopy correction */
321444 }
322445
323446 /* end of decoding */
324447 if (endOnInput) {
325448 /* Nb of output bytes decoded */
326
- return (int) (((char *)op) - dest);
449
+ return (int) (((char *)op) - dst);
327450 } else {
328451 /* Nb of input bytes read */
329
- return (int) (((const char *)ip) - source);
452
+ return (int) (((const char *)ip) - src);
330453 }
331454
332455 /* Overflow error detected */
333456 _output_error:
334
- return -1;
457
+ return (int) (-(((const char *)ip) - src)) - 1;
335458 }
336459
337460 int LZ4_decompress_safe(const char *source, char *dest,
338461 int compressedSize, int maxDecompressedSize)
339462 {
340
- return LZ4_decompress_generic(source, dest, compressedSize,
341
- maxDecompressedSize, endOnInputSize, full, 0,
342
- noDict, (BYTE *)dest, NULL, 0);
463
+ return LZ4_decompress_generic(source, dest,
464
+ compressedSize, maxDecompressedSize,
465
+ endOnInputSize, decode_full_block,
466
+ noDict, (BYTE *)dest, NULL, 0);
343467 }
344468
345
-int LZ4_decompress_safe_partial(const char *source, char *dest,
346
- int compressedSize, int targetOutputSize, int maxDecompressedSize)
469
+int LZ4_decompress_safe_partial(const char *src, char *dst,
470
+ int compressedSize, int targetOutputSize, int dstCapacity)
347471 {
348
- return LZ4_decompress_generic(source, dest, compressedSize,
349
- maxDecompressedSize, endOnInputSize, partial,
350
- targetOutputSize, noDict, (BYTE *)dest, NULL, 0);
472
+ dstCapacity = min(targetOutputSize, dstCapacity);
473
+ return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
474
+ endOnInputSize, partial_decode,
475
+ noDict, (BYTE *)dst, NULL, 0);
351476 }
352477
353478 int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
354479 {
355480 return LZ4_decompress_generic(source, dest, 0, originalSize,
356
- endOnOutputSize, full, 0, withPrefix64k,
357
- (BYTE *)(dest - 64 * KB), NULL, 64 * KB);
481
+ endOnOutputSize, decode_full_block,
482
+ withPrefix64k,
483
+ (BYTE *)dest - 64 * KB, NULL, 0);
358484 }
485
+
486
+/* ===== Instantiate a few more decoding cases, used more than once. ===== */
487
+
488
+int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest,
489
+ int compressedSize, int maxOutputSize)
490
+{
491
+ return LZ4_decompress_generic(source, dest,
492
+ compressedSize, maxOutputSize,
493
+ endOnInputSize, decode_full_block,
494
+ withPrefix64k,
495
+ (BYTE *)dest - 64 * KB, NULL, 0);
496
+}
497
+
498
+static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest,
499
+ int compressedSize,
500
+ int maxOutputSize,
501
+ size_t prefixSize)
502
+{
503
+ return LZ4_decompress_generic(source, dest,
504
+ compressedSize, maxOutputSize,
505
+ endOnInputSize, decode_full_block,
506
+ noDict,
507
+ (BYTE *)dest - prefixSize, NULL, 0);
508
+}
509
+
510
+int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
511
+ int compressedSize, int maxOutputSize,
512
+ const void *dictStart, size_t dictSize)
513
+{
514
+ return LZ4_decompress_generic(source, dest,
515
+ compressedSize, maxOutputSize,
516
+ endOnInputSize, decode_full_block,
517
+ usingExtDict, (BYTE *)dest,
518
+ (const BYTE *)dictStart, dictSize);
519
+}
520
+
521
+static int LZ4_decompress_fast_extDict(const char *source, char *dest,
522
+ int originalSize,
523
+ const void *dictStart, size_t dictSize)
524
+{
525
+ return LZ4_decompress_generic(source, dest,
526
+ 0, originalSize,
527
+ endOnOutputSize, decode_full_block,
528
+ usingExtDict, (BYTE *)dest,
529
+ (const BYTE *)dictStart, dictSize);
530
+}
531
+
532
+/*
533
+ * The "double dictionary" mode, for use with e.g. ring buffers: the first part
534
+ * of the dictionary is passed as prefix, and the second via dictStart + dictSize.
535
+ * These routines are used only once, in LZ4_decompress_*_continue().
536
+ */
537
+static FORCE_INLINE
538
+int LZ4_decompress_safe_doubleDict(const char *source, char *dest,
539
+ int compressedSize, int maxOutputSize,
540
+ size_t prefixSize,
541
+ const void *dictStart, size_t dictSize)
542
+{
543
+ return LZ4_decompress_generic(source, dest,
544
+ compressedSize, maxOutputSize,
545
+ endOnInputSize, decode_full_block,
546
+ usingExtDict, (BYTE *)dest - prefixSize,
547
+ (const BYTE *)dictStart, dictSize);
548
+}
549
+
550
+static FORCE_INLINE
551
+int LZ4_decompress_fast_doubleDict(const char *source, char *dest,
552
+ int originalSize, size_t prefixSize,
553
+ const void *dictStart, size_t dictSize)
554
+{
555
+ return LZ4_decompress_generic(source, dest,
556
+ 0, originalSize,
557
+ endOnOutputSize, decode_full_block,
558
+ usingExtDict, (BYTE *)dest - prefixSize,
559
+ (const BYTE *)dictStart, dictSize);
560
+}
561
+
562
+/* ===== streaming decompression functions ===== */
359563
360564 int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
361565 const char *dictionary, int dictSize)
362566 {
363
- LZ4_streamDecode_t_internal *lz4sd = (LZ4_streamDecode_t_internal *) LZ4_streamDecode;
567
+ LZ4_streamDecode_t_internal *lz4sd =
568
+ &LZ4_streamDecode->internal_donotuse;
364569
365570 lz4sd->prefixSize = (size_t) dictSize;
366571 lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize;
....@@ -382,35 +587,51 @@
382587 int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
383588 const char *source, char *dest, int compressedSize, int maxOutputSize)
384589 {
385
- LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
590
+ LZ4_streamDecode_t_internal *lz4sd =
591
+ &LZ4_streamDecode->internal_donotuse;
386592 int result;
387593
388
- if (lz4sd->prefixEnd == (BYTE *)dest) {
389
- result = LZ4_decompress_generic(source, dest,
390
- compressedSize,
391
- maxOutputSize,
392
- endOnInputSize, full, 0,
393
- usingExtDict, lz4sd->prefixEnd - lz4sd->prefixSize,
394
- lz4sd->externalDict,
395
- lz4sd->extDictSize);
396
-
594
+ if (lz4sd->prefixSize == 0) {
595
+ /* The first call, no dictionary yet. */
596
+ assert(lz4sd->extDictSize == 0);
597
+ result = LZ4_decompress_safe(source, dest,
598
+ compressedSize, maxOutputSize);
397599 if (result <= 0)
398600 return result;
399
-
601
+ lz4sd->prefixSize = result;
602
+ lz4sd->prefixEnd = (BYTE *)dest + result;
603
+ } else if (lz4sd->prefixEnd == (BYTE *)dest) {
604
+ /* They're rolling the current segment. */
605
+ if (lz4sd->prefixSize >= 64 * KB - 1)
606
+ result = LZ4_decompress_safe_withPrefix64k(source, dest,
607
+ compressedSize, maxOutputSize);
608
+ else if (lz4sd->extDictSize == 0)
609
+ result = LZ4_decompress_safe_withSmallPrefix(source,
610
+ dest, compressedSize, maxOutputSize,
611
+ lz4sd->prefixSize);
612
+ else
613
+ result = LZ4_decompress_safe_doubleDict(source, dest,
614
+ compressedSize, maxOutputSize,
615
+ lz4sd->prefixSize,
616
+ lz4sd->externalDict, lz4sd->extDictSize);
617
+ if (result <= 0)
618
+ return result;
400619 lz4sd->prefixSize += result;
401
- lz4sd->prefixEnd += result;
620
+ lz4sd->prefixEnd += result;
402621 } else {
622
+ /*
623
+ * The buffer wraps around, or they're
624
+ * switching to another buffer.
625
+ */
403626 lz4sd->extDictSize = lz4sd->prefixSize;
404627 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
405
- result = LZ4_decompress_generic(source, dest,
628
+ result = LZ4_decompress_safe_forceExtDict(source, dest,
406629 compressedSize, maxOutputSize,
407
- endOnInputSize, full, 0,
408
- usingExtDict, (BYTE *)dest,
409630 lz4sd->externalDict, lz4sd->extDictSize);
410631 if (result <= 0)
411632 return result;
412633 lz4sd->prefixSize = result;
413
- lz4sd->prefixEnd = (BYTE *)dest + result;
634
+ lz4sd->prefixEnd = (BYTE *)dest + result;
414635 }
415636
416637 return result;
....@@ -422,75 +643,66 @@
422643 LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
423644 int result;
424645
425
- if (lz4sd->prefixEnd == (BYTE *)dest) {
426
- result = LZ4_decompress_generic(source, dest, 0, originalSize,
427
- endOnOutputSize, full, 0,
428
- usingExtDict,
429
- lz4sd->prefixEnd - lz4sd->prefixSize,
430
- lz4sd->externalDict, lz4sd->extDictSize);
431
-
432
- if (result <= 0)
433
- return result;
434
-
435
- lz4sd->prefixSize += originalSize;
436
- lz4sd->prefixEnd += originalSize;
437
- } else {
438
- lz4sd->extDictSize = lz4sd->prefixSize;
439
- lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
440
- result = LZ4_decompress_generic(source, dest, 0, originalSize,
441
- endOnOutputSize, full, 0,
442
- usingExtDict, (BYTE *)dest,
443
- lz4sd->externalDict, lz4sd->extDictSize);
646
+ if (lz4sd->prefixSize == 0) {
647
+ assert(lz4sd->extDictSize == 0);
648
+ result = LZ4_decompress_fast(source, dest, originalSize);
444649 if (result <= 0)
445650 return result;
446651 lz4sd->prefixSize = originalSize;
447
- lz4sd->prefixEnd = (BYTE *)dest + originalSize;
652
+ lz4sd->prefixEnd = (BYTE *)dest + originalSize;
653
+ } else if (lz4sd->prefixEnd == (BYTE *)dest) {
654
+ if (lz4sd->prefixSize >= 64 * KB - 1 ||
655
+ lz4sd->extDictSize == 0)
656
+ result = LZ4_decompress_fast(source, dest,
657
+ originalSize);
658
+ else
659
+ result = LZ4_decompress_fast_doubleDict(source, dest,
660
+ originalSize, lz4sd->prefixSize,
661
+ lz4sd->externalDict, lz4sd->extDictSize);
662
+ if (result <= 0)
663
+ return result;
664
+ lz4sd->prefixSize += originalSize;
665
+ lz4sd->prefixEnd += originalSize;
666
+ } else {
667
+ lz4sd->extDictSize = lz4sd->prefixSize;
668
+ lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
669
+ result = LZ4_decompress_fast_extDict(source, dest,
670
+ originalSize, lz4sd->externalDict, lz4sd->extDictSize);
671
+ if (result <= 0)
672
+ return result;
673
+ lz4sd->prefixSize = originalSize;
674
+ lz4sd->prefixEnd = (BYTE *)dest + originalSize;
448675 }
449
-
450676 return result;
451677 }
452678
453
-/*
454
- * Advanced decoding functions :
455
- * *_usingDict() :
456
- * These decoding functions work the same as "_continue" ones,
457
- * the dictionary must be explicitly provided within parameters
458
- */
459
-static FORCE_INLINE int LZ4_decompress_usingDict_generic(const char *source,
460
- char *dest, int compressedSize, int maxOutputSize, int safe,
461
- const char *dictStart, int dictSize)
679
+int LZ4_decompress_safe_usingDict(const char *source, char *dest,
680
+ int compressedSize, int maxOutputSize,
681
+ const char *dictStart, int dictSize)
462682 {
463683 if (dictSize == 0)
464
- return LZ4_decompress_generic(source, dest,
465
- compressedSize, maxOutputSize, safe, full, 0,
466
- noDict, (BYTE *)dest, NULL, 0);
467
- if (dictStart + dictSize == dest) {
468
- if (dictSize >= (int)(64 * KB - 1))
469
- return LZ4_decompress_generic(source, dest,
470
- compressedSize, maxOutputSize, safe, full, 0,
471
- withPrefix64k, (BYTE *)dest - 64 * KB, NULL, 0);
472
- return LZ4_decompress_generic(source, dest, compressedSize,
473
- maxOutputSize, safe, full, 0, noDict,
474
- (BYTE *)dest - dictSize, NULL, 0);
684
+ return LZ4_decompress_safe(source, dest,
685
+ compressedSize, maxOutputSize);
686
+ if (dictStart+dictSize == dest) {
687
+ if (dictSize >= 64 * KB - 1)
688
+ return LZ4_decompress_safe_withPrefix64k(source, dest,
689
+ compressedSize, maxOutputSize);
690
+ return LZ4_decompress_safe_withSmallPrefix(source, dest,
691
+ compressedSize, maxOutputSize, dictSize);
475692 }
476
- return LZ4_decompress_generic(source, dest, compressedSize,
477
- maxOutputSize, safe, full, 0, usingExtDict,
478
- (BYTE *)dest, (const BYTE *)dictStart, dictSize);
479
-}
480
-
481
-int LZ4_decompress_safe_usingDict(const char *source, char *dest,
482
- int compressedSize, int maxOutputSize,
483
- const char *dictStart, int dictSize)
484
-{
485
- return LZ4_decompress_usingDict_generic(source, dest,
486
- compressedSize, maxOutputSize, 1, dictStart, dictSize);
693
+ return LZ4_decompress_safe_forceExtDict(source, dest,
694
+ compressedSize, maxOutputSize, dictStart, dictSize);
487695 }
488696
489697 int LZ4_decompress_fast_usingDict(const char *source, char *dest,
490
- int originalSize, const char *dictStart, int dictSize)
698
+ int originalSize,
699
+ const char *dictStart, int dictSize)
491700 {
492
- return LZ4_decompress_usingDict_generic(source, dest, 0,
493
- originalSize, 0, dictStart, dictSize);
701
+ if (dictSize == 0 || dictStart + dictSize == dest)
702
+ return LZ4_decompress_fast(source, dest, originalSize);
703
+
704
+ return LZ4_decompress_fast_extDict(source, dest, originalSize,
705
+ dictStart, dictSize);
494706 }
495707
496708 #ifndef STATIC