1 /* 1 /*
2 * LZ4 - Fast LZ compression algorithm 2 * LZ4 - Fast LZ compression algorithm
3 * Copyright (C) 2011 - 2016, Yann Collet. 3 * Copyright (C) 2011 - 2016, Yann Collet.
4 * BSD 2 - Clause License (http://www.opensour 4 * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php)
5 * Redistribution and use in source and binary 5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that t 6 * modification, are permitted provided that the following conditions are
7 * met: 7 * met:
8 * * Redistributions of source code must 8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and 9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must 10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions a 11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials 12 * in the documentation and/or other materials provided with the
13 * distribution. 13 * distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT 14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
15 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTI 15 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCH 16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
18 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIR 18 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGE 19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, S 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE PO 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 * You can contact the author at : 25 * You can contact the author at :
26 * - LZ4 homepage : http://www.lz4.org 26 * - LZ4 homepage : http://www.lz4.org
27 * - LZ4 source repository : https://gith 27 * - LZ4 source repository : https://github.com/lz4/lz4
28 * 28 *
29 * Changed for kernel usage by: 29 * Changed for kernel usage by:
30 * Sven Schmidt <4sschmid@informatik.uni- 30 * Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
31 */ 31 */
32 32
33 /*-************************************ 33 /*-************************************
34 * Dependencies 34 * Dependencies
35 **************************************/ 35 **************************************/
36 #include <linux/lz4.h> 36 #include <linux/lz4.h>
37 #include "lz4defs.h" 37 #include "lz4defs.h"
38 #include <linux/init.h> 38 #include <linux/init.h>
39 #include <linux/module.h> 39 #include <linux/module.h>
40 #include <linux/kernel.h> 40 #include <linux/kernel.h>
41 #include <linux/unaligned.h> 41 #include <linux/unaligned.h>
42 42
43 /*-***************************** 43 /*-*****************************
44 * Decompression functions 44 * Decompression functions
45 *******************************/ 45 *******************************/
46 46
47 #define DEBUGLOG(l, ...) {} /* disabled */ 47 #define DEBUGLOG(l, ...) {} /* disabled */
48 48
49 #ifndef assert 49 #ifndef assert
50 #define assert(condition) ((void)0) 50 #define assert(condition) ((void)0)
51 #endif 51 #endif
52 52
53 /* 53 /*
54 * LZ4_decompress_generic() : 54 * LZ4_decompress_generic() :
55 * This generic decompression function covers 55 * This generic decompression function covers all use cases.
56 * It shall be instantiated several times, usi 56 * It shall be instantiated several times, using different sets of directives.
57 * Note that it is important for performance t 57 * Note that it is important for performance that this function really get inlined,
58 * in order to remove useless branches during 58 * in order to remove useless branches during compilation optimization.
59 */ 59 */
60 static FORCE_INLINE int LZ4_decompress_generic 60 static FORCE_INLINE int LZ4_decompress_generic(
61 const char * const src, 61 const char * const src,
62 char * const dst, 62 char * const dst,
63 int srcSize, 63 int srcSize,
64 /* 64 /*
65 * If endOnInput == endOnInput 65 * If endOnInput == endOnInputSize,
66 * this value is `dstCapacity` 66 * this value is `dstCapacity`
67 */ 67 */
68 int outputSize, 68 int outputSize,
69 /* endOnOutputSize, endOnInputSize */ 69 /* endOnOutputSize, endOnInputSize */
70 endCondition_directive endOnInput, 70 endCondition_directive endOnInput,
71 /* full, partial */ 71 /* full, partial */
72 earlyEnd_directive partialDecoding, 72 earlyEnd_directive partialDecoding,
73 /* noDict, withPrefix64k, usingExtDic 73 /* noDict, withPrefix64k, usingExtDict */
74 dict_directive dict, 74 dict_directive dict,
75 /* always <= dst, == dst when no pref 75 /* always <= dst, == dst when no prefix */
76 const BYTE * const lowPrefix, 76 const BYTE * const lowPrefix,
77 /* only if dict == usingExtDict */ 77 /* only if dict == usingExtDict */
78 const BYTE * const dictStart, 78 const BYTE * const dictStart,
79 /* note : = 0 if noDict */ 79 /* note : = 0 if noDict */
80 const size_t dictSize 80 const size_t dictSize
81 ) 81 )
82 { 82 {
83 const BYTE *ip = (const BYTE *) src; 83 const BYTE *ip = (const BYTE *) src;
84 const BYTE * const iend = ip + srcSize 84 const BYTE * const iend = ip + srcSize;
85 85
86 BYTE *op = (BYTE *) dst; 86 BYTE *op = (BYTE *) dst;
87 BYTE * const oend = op + outputSize; 87 BYTE * const oend = op + outputSize;
88 BYTE *cpy; 88 BYTE *cpy;
89 89
90 const BYTE * const dictEnd = (const BY 90 const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
91 static const unsigned int inc32table[8 91 static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
92 static const int dec64table[8] = {0, 0 92 static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
93 93
94 const int safeDecode = (endOnInput == 94 const int safeDecode = (endOnInput == endOnInputSize);
95 const int checkOffset = ((safeDecode) 95 const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
96 96
97 /* Set up the "end" pointers for the s 97 /* Set up the "end" pointers for the shortcut. */
98 const BYTE *const shortiend = iend - 98 const BYTE *const shortiend = iend -
99 (endOnInput ? 14 : 8) /*maxLL* 99 (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
100 const BYTE *const shortoend = oend - 100 const BYTE *const shortoend = oend -
101 (endOnInput ? 14 : 8) /*maxLL* 101 (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
102 102
103 DEBUGLOG(5, "%s (srcSize:%i, dstSize:% 103 DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
104 srcSize, outputSize); 104 srcSize, outputSize);
105 105
106 /* Special cases */ 106 /* Special cases */
107 assert(lowPrefix <= op); 107 assert(lowPrefix <= op);
108 assert(src != NULL); 108 assert(src != NULL);
109 109
110 /* Empty output buffer */ 110 /* Empty output buffer */
111 if ((endOnInput) && (unlikely(outputSi 111 if ((endOnInput) && (unlikely(outputSize == 0)))
112 return ((srcSize == 1) && (*ip 112 return ((srcSize == 1) && (*ip == 0)) ? 0 : -1;
113 113
114 if ((!endOnInput) && (unlikely(outputS 114 if ((!endOnInput) && (unlikely(outputSize == 0)))
115 return (*ip == 0 ? 1 : -1); 115 return (*ip == 0 ? 1 : -1);
116 116
117 if ((endOnInput) && unlikely(srcSize = 117 if ((endOnInput) && unlikely(srcSize == 0))
118 return -1; 118 return -1;
119 119
120 /* Main Loop : decode sequences */ 120 /* Main Loop : decode sequences */
121 while (1) { 121 while (1) {
122 size_t length; 122 size_t length;
123 const BYTE *match; 123 const BYTE *match;
124 size_t offset; 124 size_t offset;
125 125
126 /* get literal length */ 126 /* get literal length */
127 unsigned int const token = *ip 127 unsigned int const token = *ip++;
128 length = token>>ML_BITS; 128 length = token>>ML_BITS;
129 129
130 /* ip < iend before the increm 130 /* ip < iend before the increment */
131 assert(!endOnInput || ip <= ie 131 assert(!endOnInput || ip <= iend);
132 132
133 /* 133 /*
134 * A two-stage shortcut for th 134 * A two-stage shortcut for the most common case:
135 * 1) If the literal length is 135 * 1) If the literal length is 0..14, and there is enough
136 * space, enter the shortcut a 136 * space, enter the shortcut and copy 16 bytes on behalf
137 * of the literals (in the fas 137 * of the literals (in the fast mode, only 8 bytes can be
138 * safely copied this way). 138 * safely copied this way).
139 * 2) Further if the match len 139 * 2) Further if the match length is 4..18, copy 18 bytes
140 * in a similar manner; but we 140 * in a similar manner; but we ensure that there's enough
141 * space in the output for tho 141 * space in the output for those 18 bytes earlier, upon
142 * entering the shortcut (in o 142 * entering the shortcut (in other words, there is a
143 * combined check for both sta 143 * combined check for both stages).
144 * 144 *
145 * The & in the likely() below 145 * The & in the likely() below is intentionally not && so that
146 * some compilers can produce 146 * some compilers can produce better parallelized runtime code
147 */ 147 */
148 if ((endOnInput ? length != RU 148 if ((endOnInput ? length != RUN_MASK : length <= 8)
149 /* 149 /*
150 * strictly "less than" on 150 * strictly "less than" on input, to re-enter
151 * the loop with at least o 151 * the loop with at least one byte
152 */ 152 */
153 && likely((endOnInput ? ip 153 && likely((endOnInput ? ip < shortiend : 1) &
154 (op <= shortoend) 154 (op <= shortoend))) {
155 /* Copy the literals * 155 /* Copy the literals */
156 LZ4_memcpy(op, ip, end 156 LZ4_memcpy(op, ip, endOnInput ? 16 : 8);
157 op += length; ip += le 157 op += length; ip += length;
158 158
159 /* 159 /*
160 * The second stage: 160 * The second stage:
161 * prepare for match c 161 * prepare for match copying, decode full info.
162 * If it doesn't work 162 * If it doesn't work out, the info won't be wasted.
163 */ 163 */
164 length = token & ML_MA 164 length = token & ML_MASK; /* match length */
165 offset = LZ4_readLE16( 165 offset = LZ4_readLE16(ip);
166 ip += 2; 166 ip += 2;
167 match = op - offset; 167 match = op - offset;
168 assert(match <= op); / 168 assert(match <= op); /* check overflow */
169 169
170 /* Do not deal with ov 170 /* Do not deal with overlapping matches. */
171 if ((length != ML_MASK 171 if ((length != ML_MASK) &&
172 (offset >= 8) && 172 (offset >= 8) &&
173 (dict == withPrefi 173 (dict == withPrefix64k || match >= lowPrefix)) {
174 /* Copy the ma 174 /* Copy the match. */
175 LZ4_memcpy(op 175 LZ4_memcpy(op + 0, match + 0, 8);
176 LZ4_memcpy(op 176 LZ4_memcpy(op + 8, match + 8, 8);
177 LZ4_memcpy(op 177 LZ4_memcpy(op + 16, match + 16, 2);
178 op += length + 178 op += length + MINMATCH;
179 /* Both stages 179 /* Both stages worked, load the next token. */
180 continue; 180 continue;
181 } 181 }
182 182
183 /* 183 /*
184 * The second stage di 184 * The second stage didn't work out, but the info
185 * is ready. Propel it 185 * is ready. Propel it right to the point of match
186 * copying. 186 * copying.
187 */ 187 */
188 goto _copy_match; 188 goto _copy_match;
189 } 189 }
190 190
191 /* decode literal length */ 191 /* decode literal length */
192 if (length == RUN_MASK) { 192 if (length == RUN_MASK) {
193 unsigned int s; 193 unsigned int s;
194 194
195 if (unlikely(endOnInpu 195 if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
196 /* overflow de 196 /* overflow detection */
197 goto _output_e 197 goto _output_error;
198 } 198 }
199 do { 199 do {
200 s = *ip++; 200 s = *ip++;
201 length += s; 201 length += s;
202 } while (likely(endOnI 202 } while (likely(endOnInput
203 ? ip < iend - 203 ? ip < iend - RUN_MASK
204 : 1) & (s == 2 204 : 1) & (s == 255));
205 205
206 if ((safeDecode) 206 if ((safeDecode)
207 && unlikely((uptrv 207 && unlikely((uptrval)(op) +
208 length 208 length < (uptrval)(op))) {
209 /* overflow de 209 /* overflow detection */
210 goto _output_e 210 goto _output_error;
211 } 211 }
212 if ((safeDecode) 212 if ((safeDecode)
213 && unlikely((uptrv 213 && unlikely((uptrval)(ip) +
214 length 214 length < (uptrval)(ip))) {
215 /* overflow de 215 /* overflow detection */
216 goto _output_e 216 goto _output_error;
217 } 217 }
218 } 218 }
219 219
220 /* copy literals */ 220 /* copy literals */
221 cpy = op + length; 221 cpy = op + length;
222 LZ4_STATIC_ASSERT(MFLIMIT >= W 222 LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
223 223
224 if (((endOnInput) && ((cpy > o 224 if (((endOnInput) && ((cpy > oend - MFLIMIT)
225 || (ip + length > iend 225 || (ip + length > iend - (2 + 1 + LASTLITERALS))))
226 || ((!endOnInput) && ( 226 || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
227 if (partialDecoding) { 227 if (partialDecoding) {
228 if (cpy > oend 228 if (cpy > oend) {
229 /* 229 /*
230 * Par 230 * Partial decoding :
231 * sto 231 * stop in the middle of literal segment
232 */ 232 */
233 cpy = 233 cpy = oend;
234 length 234 length = oend - op;
235 } 235 }
236 if ((endOnInpu 236 if ((endOnInput)
237 && (ip 237 && (ip + length > iend)) {
238 /* 238 /*
239 * Err 239 * Error :
240 * rea 240 * read attempt beyond
241 * end 241 * end of input buffer
242 */ 242 */
243 goto _ 243 goto _output_error;
244 } 244 }
245 } else { 245 } else {
246 if ((!endOnInp 246 if ((!endOnInput)
247 && (cp 247 && (cpy != oend)) {
248 /* 248 /*
249 * Err 249 * Error :
250 * blo 250 * block decoding must
251 * sto 251 * stop exactly there
252 */ 252 */
253 goto _ 253 goto _output_error;
254 } 254 }
255 if ((endOnInpu 255 if ((endOnInput)
256 && ((i 256 && ((ip + length != iend)
257 || (cp 257 || (cpy > oend))) {
258 /* 258 /*
259 * Err 259 * Error :
260 * inp 260 * input must be consumed
261 */ 261 */
262 goto _ 262 goto _output_error;
263 } 263 }
264 } 264 }
265 265
266 /* 266 /*
267 * supports overlappin 267 * supports overlapping memory regions; only matters
268 * for in-place decomp 268 * for in-place decompression scenarios
269 */ 269 */
270 LZ4_memmove(op, ip, le 270 LZ4_memmove(op, ip, length);
271 ip += length; 271 ip += length;
272 op += length; 272 op += length;
273 273
274 /* Necessarily EOF whe 274 /* Necessarily EOF when !partialDecoding.
275 * When partialDecodin 275 * When partialDecoding, it is EOF if we've either
276 * filled the output b 276 * filled the output buffer or
277 * can't proceed with 277 * can't proceed with reading an offset for following match.
278 */ 278 */
279 if (!partialDecoding | 279 if (!partialDecoding || (cpy == oend) || (ip >= (iend - 2)))
280 break; 280 break;
281 } else { 281 } else {
282 /* may overwrite up to 282 /* may overwrite up to WILDCOPYLENGTH beyond cpy */
283 LZ4_wildCopy(op, ip, c 283 LZ4_wildCopy(op, ip, cpy);
284 ip += length; 284 ip += length;
285 op = cpy; 285 op = cpy;
286 } 286 }
287 287
288 /* get offset */ 288 /* get offset */
289 offset = LZ4_readLE16(ip); 289 offset = LZ4_readLE16(ip);
290 ip += 2; 290 ip += 2;
291 match = op - offset; 291 match = op - offset;
292 292
293 /* get matchlength */ 293 /* get matchlength */
294 length = token & ML_MASK; 294 length = token & ML_MASK;
295 295
296 _copy_match: 296 _copy_match:
297 if ((checkOffset) && (unlikely 297 if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
298 /* Error : offset outs 298 /* Error : offset outside buffers */
299 goto _output_error; 299 goto _output_error;
300 } 300 }
301 301
302 /* costs ~1%; silence an msan 302 /* costs ~1%; silence an msan warning when offset == 0 */
303 /* 303 /*
304 * note : when partialDecoding 304 * note : when partialDecoding, there is no guarantee that
305 * at least 4 bytes remain ava 305 * at least 4 bytes remain available in output buffer
306 */ 306 */
307 if (!partialDecoding) { 307 if (!partialDecoding) {
308 assert(oend > op); 308 assert(oend > op);
309 assert(oend - op >= 4) 309 assert(oend - op >= 4);
310 310
311 LZ4_write32(op, (U32)o 311 LZ4_write32(op, (U32)offset);
312 } 312 }
313 313
314 if (length == ML_MASK) { 314 if (length == ML_MASK) {
315 unsigned int s; 315 unsigned int s;
316 316
317 do { 317 do {
318 s = *ip++; 318 s = *ip++;
319 319
320 if ((endOnInpu 320 if ((endOnInput) && (ip > iend - LASTLITERALS))
321 goto _ 321 goto _output_error;
322 322
323 length += s; 323 length += s;
324 } while (s == 255); 324 } while (s == 255);
325 325
326 if ((safeDecode) 326 if ((safeDecode)
327 && unlikely( 327 && unlikely(
328 (uptrv 328 (uptrval)(op) + length < (uptrval)op)) {
329 /* overflow de 329 /* overflow detection */
330 goto _output_e 330 goto _output_error;
331 } 331 }
332 } 332 }
333 333
334 length += MINMATCH; 334 length += MINMATCH;
335 335
336 /* match starting within exter 336 /* match starting within external dictionary */
337 if ((dict == usingExtDict) && 337 if ((dict == usingExtDict) && (match < lowPrefix)) {
338 if (unlikely(op + leng 338 if (unlikely(op + length > oend - LASTLITERALS)) {
339 /* doesn't res 339 /* doesn't respect parsing restriction */
340 if (!partialDe 340 if (!partialDecoding)
341 goto _ 341 goto _output_error;
342 length = min(l 342 length = min(length, (size_t)(oend - op));
343 } 343 }
344 344
345 if (length <= (size_t) 345 if (length <= (size_t)(lowPrefix - match)) {
346 /* 346 /*
347 * match fits 347 * match fits entirely within external
348 * dictionary 348 * dictionary : just copy
349 */ 349 */
350 memmove(op, di 350 memmove(op, dictEnd - (lowPrefix - match),
351 length 351 length);
352 op += length; 352 op += length;
353 } else { 353 } else {
354 /* 354 /*
355 * match stret 355 * match stretches into both external
356 * dictionary 356 * dictionary and current block
357 */ 357 */
358 size_t const c 358 size_t const copySize = (size_t)(lowPrefix - match);
359 size_t const r 359 size_t const restSize = length - copySize;
360 360
361 LZ4_memcpy(op, 361 LZ4_memcpy(op, dictEnd - copySize, copySize);
362 op += copySize 362 op += copySize;
363 if (restSize > 363 if (restSize > (size_t)(op - lowPrefix)) {
364 /* ove 364 /* overlap copy */
365 BYTE * 365 BYTE * const endOfMatch = op + restSize;
366 const 366 const BYTE *copyFrom = lowPrefix;
367 367
368 while 368 while (op < endOfMatch)
369 369 *op++ = *copyFrom++;
370 } else { 370 } else {
371 LZ4_me 371 LZ4_memcpy(op, lowPrefix, restSize);
372 op += 372 op += restSize;
373 } 373 }
374 } 374 }
375 continue; 375 continue;
376 } 376 }
377 377
378 /* copy match within block */ 378 /* copy match within block */
379 cpy = op + length; 379 cpy = op + length;
380 380
381 /* 381 /*
382 * partialDecoding : 382 * partialDecoding :
383 * may not respect endBlock pa 383 * may not respect endBlock parsing restrictions
384 */ 384 */
385 assert(op <= oend); 385 assert(op <= oend);
386 if (partialDecoding && 386 if (partialDecoding &&
387 (cpy > oend - MATCH_SAFEGU 387 (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
388 size_t const mlen = mi 388 size_t const mlen = min(length, (size_t)(oend - op));
389 const BYTE * const mat 389 const BYTE * const matchEnd = match + mlen;
390 BYTE * const copyEnd = 390 BYTE * const copyEnd = op + mlen;
391 391
392 if (matchEnd > op) { 392 if (matchEnd > op) {
393 /* overlap cop 393 /* overlap copy */
394 while (op < co 394 while (op < copyEnd)
395 *op++ 395 *op++ = *match++;
396 } else { 396 } else {
397 LZ4_memcpy(op, 397 LZ4_memcpy(op, match, mlen);
398 } 398 }
399 op = copyEnd; 399 op = copyEnd;
400 if (op == oend) 400 if (op == oend)
401 break; 401 break;
402 continue; 402 continue;
403 } 403 }
404 404
405 if (unlikely(offset < 8)) { 405 if (unlikely(offset < 8)) {
406 op[0] = match[0]; 406 op[0] = match[0];
407 op[1] = match[1]; 407 op[1] = match[1];
408 op[2] = match[2]; 408 op[2] = match[2];
409 op[3] = match[3]; 409 op[3] = match[3];
410 match += inc32table[of 410 match += inc32table[offset];
411 LZ4_memcpy(op + 4, mat 411 LZ4_memcpy(op + 4, match, 4);
412 match -= dec64table[of 412 match -= dec64table[offset];
413 } else { 413 } else {
414 LZ4_copy8(op, match); 414 LZ4_copy8(op, match);
415 match += 8; 415 match += 8;
416 } 416 }
417 417
418 op += 8; 418 op += 8;
419 419
420 if (unlikely(cpy > oend - MATC 420 if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
421 BYTE * const oCopyLimi 421 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
422 422
423 if (cpy > oend - LASTL 423 if (cpy > oend - LASTLITERALS) {
424 /* 424 /*
425 * Error : las 425 * Error : last LASTLITERALS bytes
426 * must be lit 426 * must be literals (uncompressed)
427 */ 427 */
428 goto _output_e 428 goto _output_error;
429 } 429 }
430 430
431 if (op < oCopyLimit) { 431 if (op < oCopyLimit) {
432 LZ4_wildCopy(o 432 LZ4_wildCopy(op, match, oCopyLimit);
433 match += oCopy 433 match += oCopyLimit - op;
434 op = oCopyLimi 434 op = oCopyLimit;
435 } 435 }
436 while (op < cpy) 436 while (op < cpy)
437 *op++ = *match 437 *op++ = *match++;
438 } else { 438 } else {
439 LZ4_copy8(op, match); 439 LZ4_copy8(op, match);
440 if (length > 16) 440 if (length > 16)
441 LZ4_wildCopy(o 441 LZ4_wildCopy(op + 8, match + 8, cpy);
442 } 442 }
443 op = cpy; /* wildcopy correcti 443 op = cpy; /* wildcopy correction */
444 } 444 }
445 445
446 /* end of decoding */ 446 /* end of decoding */
447 if (endOnInput) { 447 if (endOnInput) {
448 /* Nb of output bytes decoded 448 /* Nb of output bytes decoded */
449 return (int) (((char *)op) - d 449 return (int) (((char *)op) - dst);
450 } else { 450 } else {
451 /* Nb of input bytes read */ 451 /* Nb of input bytes read */
452 return (int) (((const char *)i 452 return (int) (((const char *)ip) - src);
453 } 453 }
454 454
455 /* Overflow error detected */ 455 /* Overflow error detected */
456 _output_error: 456 _output_error:
457 return (int) (-(((const char *)ip) - s 457 return (int) (-(((const char *)ip) - src)) - 1;
458 } 458 }
459 459
460 int LZ4_decompress_safe(const char *source, ch 460 int LZ4_decompress_safe(const char *source, char *dest,
461 int compressedSize, int maxDecompresse 461 int compressedSize, int maxDecompressedSize)
462 { 462 {
463 return LZ4_decompress_generic(source, 463 return LZ4_decompress_generic(source, dest,
464 compress 464 compressedSize, maxDecompressedSize,
465 endOnInp 465 endOnInputSize, decode_full_block,
466 noDict, 466 noDict, (BYTE *)dest, NULL, 0);
467 } 467 }
468 468
469 int LZ4_decompress_safe_partial(const char *sr 469 int LZ4_decompress_safe_partial(const char *src, char *dst,
470 int compressedSize, int targetOutputSi 470 int compressedSize, int targetOutputSize, int dstCapacity)
471 { 471 {
472 dstCapacity = min(targetOutputSize, ds 472 dstCapacity = min(targetOutputSize, dstCapacity);
473 return LZ4_decompress_generic(src, dst 473 return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
474 endOnInp 474 endOnInputSize, partial_decode,
475 noDict, 475 noDict, (BYTE *)dst, NULL, 0);
476 } 476 }
477 477
478 int LZ4_decompress_fast(const char *source, ch 478 int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
479 { 479 {
480 return LZ4_decompress_generic(source, 480 return LZ4_decompress_generic(source, dest, 0, originalSize,
481 endOnOut 481 endOnOutputSize, decode_full_block,
482 withPref 482 withPrefix64k,
483 (BYTE *) 483 (BYTE *)dest - 64 * KB, NULL, 0);
484 } 484 }
485 485
486 /* ===== Instantiate a few more decoding cases 486 /* ===== Instantiate a few more decoding cases, used more than once. ===== */
487 487
488 static int LZ4_decompress_safe_withPrefix64k(c 488 static int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest,
489 int comp 489 int compressedSize, int maxOutputSize)
490 { 490 {
491 return LZ4_decompress_generic(source, 491 return LZ4_decompress_generic(source, dest,
492 compress 492 compressedSize, maxOutputSize,
493 endOnInp 493 endOnInputSize, decode_full_block,
494 withPref 494 withPrefix64k,
495 (BYTE *) 495 (BYTE *)dest - 64 * KB, NULL, 0);
496 } 496 }
497 497
498 static int LZ4_decompress_safe_withSmallPrefix 498 static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest,
499 499 int compressedSize,
500 500 int maxOutputSize,
501 501 size_t prefixSize)
502 { 502 {
503 return LZ4_decompress_generic(source, 503 return LZ4_decompress_generic(source, dest,
504 compress 504 compressedSize, maxOutputSize,
505 endOnInp 505 endOnInputSize, decode_full_block,
506 noDict, 506 noDict,
507 (BYTE *) 507 (BYTE *)dest - prefixSize, NULL, 0);
508 } 508 }
509 509
510 static int LZ4_decompress_safe_forceExtDict(co 510 static int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
511 in 511 int compressedSize, int maxOutputSize,
512 co 512 const void *dictStart, size_t dictSize)
513 { 513 {
514 return LZ4_decompress_generic(source, 514 return LZ4_decompress_generic(source, dest,
515 compress 515 compressedSize, maxOutputSize,
516 endOnInp 516 endOnInputSize, decode_full_block,
517 usingExt 517 usingExtDict, (BYTE *)dest,
518 (const B 518 (const BYTE *)dictStart, dictSize);
519 } 519 }
520 520
521 static int LZ4_decompress_fast_extDict(const c 521 static int LZ4_decompress_fast_extDict(const char *source, char *dest,
522 int ori 522 int originalSize,
523 const v 523 const void *dictStart, size_t dictSize)
524 { 524 {
525 return LZ4_decompress_generic(source, 525 return LZ4_decompress_generic(source, dest,
526 0, origi 526 0, originalSize,
527 endOnOut 527 endOnOutputSize, decode_full_block,
528 usingExt 528 usingExtDict, (BYTE *)dest,
529 (const B 529 (const BYTE *)dictStart, dictSize);
530 } 530 }
531 531
532 /* 532 /*
533 * The "double dictionary" mode, for use with 533 * The "double dictionary" mode, for use with e.g. ring buffers: the first part
534 * of the dictionary is passed as prefix, and 534 * of the dictionary is passed as prefix, and the second via dictStart + dictSize.
535 * These routines are used only once, in LZ4_d 535 * These routines are used only once, in LZ4_decompress_*_continue().
536 */ 536 */
537 static FORCE_INLINE 537 static FORCE_INLINE
538 int LZ4_decompress_safe_doubleDict(const char 538 int LZ4_decompress_safe_doubleDict(const char *source, char *dest,
539 int compres 539 int compressedSize, int maxOutputSize,
540 size_t pref 540 size_t prefixSize,
541 const void 541 const void *dictStart, size_t dictSize)
542 { 542 {
543 return LZ4_decompress_generic(source, 543 return LZ4_decompress_generic(source, dest,
544 compress 544 compressedSize, maxOutputSize,
545 endOnInp 545 endOnInputSize, decode_full_block,
546 usingExt 546 usingExtDict, (BYTE *)dest - prefixSize,
547 (const B 547 (const BYTE *)dictStart, dictSize);
548 } 548 }
549 549
550 static FORCE_INLINE 550 static FORCE_INLINE
551 int LZ4_decompress_fast_doubleDict(const char 551 int LZ4_decompress_fast_doubleDict(const char *source, char *dest,
552 int origina 552 int originalSize, size_t prefixSize,
553 const void 553 const void *dictStart, size_t dictSize)
554 { 554 {
555 return LZ4_decompress_generic(source, 555 return LZ4_decompress_generic(source, dest,
556 0, origi 556 0, originalSize,
557 endOnOut 557 endOnOutputSize, decode_full_block,
558 usingExt 558 usingExtDict, (BYTE *)dest - prefixSize,
559 (const B 559 (const BYTE *)dictStart, dictSize);
560 } 560 }
561 561
562 /* ===== streaming decompression functions === 562 /* ===== streaming decompression functions ===== */
563 563
564 int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ 564 int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
565 const char *dictionary, int dictSize) 565 const char *dictionary, int dictSize)
566 { 566 {
567 LZ4_streamDecode_t_internal *lz4sd = 567 LZ4_streamDecode_t_internal *lz4sd =
568 &LZ4_streamDecode->internal_do 568 &LZ4_streamDecode->internal_donotuse;
569 569
570 lz4sd->prefixSize = (size_t) dictSize; 570 lz4sd->prefixSize = (size_t) dictSize;
571 lz4sd->prefixEnd = (const BYTE *) dict 571 lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize;
572 lz4sd->externalDict = NULL; 572 lz4sd->externalDict = NULL;
573 lz4sd->extDictSize = 0; 573 lz4sd->extDictSize = 0;
574 return 1; 574 return 1;
575 } 575 }
576 576
577 /* 577 /*
578 * *_continue() : 578 * *_continue() :
579 * These decoding functions allow decompressio 579 * These decoding functions allow decompression of multiple blocks
580 * in "streaming" mode. 580 * in "streaming" mode.
581 * Previously decoded blocks must still be ava 581 * Previously decoded blocks must still be available at the memory
582 * position where they were decoded. 582 * position where they were decoded.
583 * If it's not possible, save the relevant par 583 * If it's not possible, save the relevant part of
584 * decoded data into a safe buffer, 584 * decoded data into a safe buffer,
585 * and indicate where it stands using LZ4_setS 585 * and indicate where it stands using LZ4_setStreamDecode()
586 */ 586 */
587 int LZ4_decompress_safe_continue(LZ4_streamDec 587 int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
588 const char *source, char *dest, int co 588 const char *source, char *dest, int compressedSize, int maxOutputSize)
589 { 589 {
590 LZ4_streamDecode_t_internal *lz4sd = 590 LZ4_streamDecode_t_internal *lz4sd =
591 &LZ4_streamDecode->internal_do 591 &LZ4_streamDecode->internal_donotuse;
592 int result; 592 int result;
593 593
594 if (lz4sd->prefixSize == 0) { 594 if (lz4sd->prefixSize == 0) {
595 /* The first call, no dictiona 595 /* The first call, no dictionary yet. */
596 assert(lz4sd->extDictSize == 0 596 assert(lz4sd->extDictSize == 0);
597 result = LZ4_decompress_safe(s 597 result = LZ4_decompress_safe(source, dest,
598 compressedSize, maxOut 598 compressedSize, maxOutputSize);
599 if (result <= 0) 599 if (result <= 0)
600 return result; 600 return result;
601 lz4sd->prefixSize = result; 601 lz4sd->prefixSize = result;
602 lz4sd->prefixEnd = (BYTE *)des 602 lz4sd->prefixEnd = (BYTE *)dest + result;
603 } else if (lz4sd->prefixEnd == (BYTE * 603 } else if (lz4sd->prefixEnd == (BYTE *)dest) {
604 /* They're rolling the current 604 /* They're rolling the current segment. */
605 if (lz4sd->prefixSize >= 64 * 605 if (lz4sd->prefixSize >= 64 * KB - 1)
606 result = LZ4_decompres 606 result = LZ4_decompress_safe_withPrefix64k(source, dest,
607 compressedSize 607 compressedSize, maxOutputSize);
608 else if (lz4sd->extDictSize == 608 else if (lz4sd->extDictSize == 0)
609 result = LZ4_decompres 609 result = LZ4_decompress_safe_withSmallPrefix(source,
610 dest, compress 610 dest, compressedSize, maxOutputSize,
611 lz4sd->prefixS 611 lz4sd->prefixSize);
612 else 612 else
613 result = LZ4_decompres 613 result = LZ4_decompress_safe_doubleDict(source, dest,
614 compressedSize 614 compressedSize, maxOutputSize,
615 lz4sd->prefixS 615 lz4sd->prefixSize,
616 lz4sd->externa 616 lz4sd->externalDict, lz4sd->extDictSize);
617 if (result <= 0) 617 if (result <= 0)
618 return result; 618 return result;
619 lz4sd->prefixSize += result; 619 lz4sd->prefixSize += result;
620 lz4sd->prefixEnd += result; 620 lz4sd->prefixEnd += result;
621 } else { 621 } else {
622 /* 622 /*
623 * The buffer wraps around, or 623 * The buffer wraps around, or they're
624 * switching to another buffer 624 * switching to another buffer.
625 */ 625 */
626 lz4sd->extDictSize = lz4sd->pr 626 lz4sd->extDictSize = lz4sd->prefixSize;
627 lz4sd->externalDict = lz4sd->p 627 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
628 result = LZ4_decompress_safe_f 628 result = LZ4_decompress_safe_forceExtDict(source, dest,
629 compressedSize, maxOut 629 compressedSize, maxOutputSize,
630 lz4sd->externalDict, l 630 lz4sd->externalDict, lz4sd->extDictSize);
631 if (result <= 0) 631 if (result <= 0)
632 return result; 632 return result;
633 lz4sd->prefixSize = result; 633 lz4sd->prefixSize = result;
634 lz4sd->prefixEnd = (BYTE *)de 634 lz4sd->prefixEnd = (BYTE *)dest + result;
635 } 635 }
636 636
637 return result; 637 return result;
638 } 638 }
639 639
640 int LZ4_decompress_fast_continue(LZ4_streamDec 640 int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
641 const char *source, char *dest, int or 641 const char *source, char *dest, int originalSize)
642 { 642 {
643 LZ4_streamDecode_t_internal *lz4sd = & 643 LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
644 int result; 644 int result;
645 645
646 if (lz4sd->prefixSize == 0) { 646 if (lz4sd->prefixSize == 0) {
647 assert(lz4sd->extDictSize == 0 647 assert(lz4sd->extDictSize == 0);
648 result = LZ4_decompress_fast(s 648 result = LZ4_decompress_fast(source, dest, originalSize);
649 if (result <= 0) 649 if (result <= 0)
650 return result; 650 return result;
651 lz4sd->prefixSize = originalSi 651 lz4sd->prefixSize = originalSize;
652 lz4sd->prefixEnd = (BYTE *)des 652 lz4sd->prefixEnd = (BYTE *)dest + originalSize;
653 } else if (lz4sd->prefixEnd == (BYTE * 653 } else if (lz4sd->prefixEnd == (BYTE *)dest) {
654 if (lz4sd->prefixSize >= 64 * 654 if (lz4sd->prefixSize >= 64 * KB - 1 ||
655 lz4sd->extDictSize == 0) 655 lz4sd->extDictSize == 0)
656 result = LZ4_decompres 656 result = LZ4_decompress_fast(source, dest,
657 657 originalSize);
658 else 658 else
659 result = LZ4_decompres 659 result = LZ4_decompress_fast_doubleDict(source, dest,
660 originalSize, 660 originalSize, lz4sd->prefixSize,
661 lz4sd->externa 661 lz4sd->externalDict, lz4sd->extDictSize);
662 if (result <= 0) 662 if (result <= 0)
663 return result; 663 return result;
664 lz4sd->prefixSize += originalS 664 lz4sd->prefixSize += originalSize;
665 lz4sd->prefixEnd += originalS 665 lz4sd->prefixEnd += originalSize;
666 } else { 666 } else {
667 lz4sd->extDictSize = lz4sd->pr 667 lz4sd->extDictSize = lz4sd->prefixSize;
668 lz4sd->externalDict = lz4sd->p 668 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
669 result = LZ4_decompress_fast_e 669 result = LZ4_decompress_fast_extDict(source, dest,
670 originalSize, lz4sd->e 670 originalSize, lz4sd->externalDict, lz4sd->extDictSize);
671 if (result <= 0) 671 if (result <= 0)
672 return result; 672 return result;
673 lz4sd->prefixSize = originalSi 673 lz4sd->prefixSize = originalSize;
674 lz4sd->prefixEnd = (BYTE *)des 674 lz4sd->prefixEnd = (BYTE *)dest + originalSize;
675 } 675 }
676 return result; 676 return result;
677 } 677 }
678 678
679 int LZ4_decompress_safe_usingDict(const char * 679 int LZ4_decompress_safe_usingDict(const char *source, char *dest,
680 int compress 680 int compressedSize, int maxOutputSize,
681 const char * 681 const char *dictStart, int dictSize)
682 { 682 {
683 if (dictSize == 0) 683 if (dictSize == 0)
684 return LZ4_decompress_safe(sou 684 return LZ4_decompress_safe(source, dest,
685 com 685 compressedSize, maxOutputSize);
686 if (dictStart+dictSize == dest) { 686 if (dictStart+dictSize == dest) {
687 if (dictSize >= 64 * KB - 1) 687 if (dictSize >= 64 * KB - 1)
688 return LZ4_decompress_ 688 return LZ4_decompress_safe_withPrefix64k(source, dest,
689 compressedSize 689 compressedSize, maxOutputSize);
690 return LZ4_decompress_safe_wit 690 return LZ4_decompress_safe_withSmallPrefix(source, dest,
691 compressedSize, maxOut 691 compressedSize, maxOutputSize, dictSize);
692 } 692 }
693 return LZ4_decompress_safe_forceExtDic 693 return LZ4_decompress_safe_forceExtDict(source, dest,
694 compressedSize, maxOutputSize, 694 compressedSize, maxOutputSize, dictStart, dictSize);
695 } 695 }
696 696
697 int LZ4_decompress_fast_usingDict(const char * 697 int LZ4_decompress_fast_usingDict(const char *source, char *dest,
698 int original 698 int originalSize,
699 const char * 699 const char *dictStart, int dictSize)
700 { 700 {
701 if (dictSize == 0 || dictStart + dictS 701 if (dictSize == 0 || dictStart + dictSize == dest)
702 return LZ4_decompress_fast(sou 702 return LZ4_decompress_fast(source, dest, originalSize);
703 703
704 return LZ4_decompress_fast_extDict(sou 704 return LZ4_decompress_fast_extDict(source, dest, originalSize,
705 dictStart, dictSize); 705 dictStart, dictSize);
706 } 706 }
707 707
708 #ifndef STATIC 708 #ifndef STATIC
709 EXPORT_SYMBOL(LZ4_decompress_safe); 709 EXPORT_SYMBOL(LZ4_decompress_safe);
710 EXPORT_SYMBOL(LZ4_decompress_safe_partial); 710 EXPORT_SYMBOL(LZ4_decompress_safe_partial);
711 EXPORT_SYMBOL(LZ4_decompress_fast); 711 EXPORT_SYMBOL(LZ4_decompress_fast);
712 EXPORT_SYMBOL(LZ4_setStreamDecode); 712 EXPORT_SYMBOL(LZ4_setStreamDecode);
713 EXPORT_SYMBOL(LZ4_decompress_safe_continue); 713 EXPORT_SYMBOL(LZ4_decompress_safe_continue);
714 EXPORT_SYMBOL(LZ4_decompress_fast_continue); 714 EXPORT_SYMBOL(LZ4_decompress_fast_continue);
715 EXPORT_SYMBOL(LZ4_decompress_safe_usingDict); 715 EXPORT_SYMBOL(LZ4_decompress_safe_usingDict);
716 EXPORT_SYMBOL(LZ4_decompress_fast_usingDict); 716 EXPORT_SYMBOL(LZ4_decompress_fast_usingDict);
717 717
718 MODULE_LICENSE("Dual BSD/GPL"); 718 MODULE_LICENSE("Dual BSD/GPL");
719 MODULE_DESCRIPTION("LZ4 decompressor"); 719 MODULE_DESCRIPTION("LZ4 decompressor");
720 #endif 720 #endif
721 721
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