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1/*
2 * LZ4 Decompressor for Linux kernel
3 *
4 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
5 *
6 * Based on LZ4 implementation by Yann Collet.
7 *
8 * LZ4 - Fast LZ compression algorithm
9 * Copyright (C) 2011-2012, Yann Collet.
10 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions are
14 * met:
15 *
16 * * Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * * Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following disclaimer
20 * in the documentation and/or other materials provided with the
21 * distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
33 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 *
35 * You can contact the author at :
36 * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
37 * - LZ4 source repository : http://code.google.com/p/lz4/
38 */
39
40#ifndef STATIC
41#include <linux/module.h>
42#include <linux/kernel.h>
43#endif
44#include <linux/lz4.h>
45
46#include <asm/unaligned.h>
47
48#include "lz4defs.h"
49
50static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
51#if LZ4_ARCH64
52static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
53#endif
54
55static int lz4_uncompress(const char *source, char *dest, int osize)
56{
57 const BYTE *ip = (const BYTE *) source;
58 const BYTE *ref;
59 BYTE *op = (BYTE *) dest;
60 BYTE * const oend = op + osize;
61 BYTE *cpy;
62 unsigned token;
63 size_t length;
64
65 while (1) {
66
67 /* get runlength */
68 token = *ip++;
69 length = (token >> ML_BITS);
70 if (length == RUN_MASK) {
71 size_t len;
72
73 len = *ip++;
74 for (; len == 255; length += 255)
75 len = *ip++;
76 if (unlikely(length > (size_t)(length + len)))
77 goto _output_error;
78 length += len;
79 }
80
81 /* copy literals */
82 cpy = op + length;
83 if (unlikely(cpy > oend - COPYLENGTH)) {
84 /*
85 * Error: not enough place for another match
86 * (min 4) + 5 literals
87 */
88 if (cpy != oend)
89 goto _output_error;
90
91 memcpy(op, ip, length);
92 ip += length;
93 break; /* EOF */
94 }
95 LZ4_WILDCOPY(ip, op, cpy);
96 ip -= (op - cpy);
97 op = cpy;
98
99 /* get offset */
100 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
101 ip += 2;
102
103 /* Error: offset create reference outside destination buffer */
104 if (unlikely(ref < (BYTE *const) dest))
105 goto _output_error;
106
107 /* get matchlength */
108 length = token & ML_MASK;
109 if (length == ML_MASK) {
110 for (; *ip == 255; length += 255)
111 ip++;
112 if (unlikely(length > (size_t)(length + *ip)))
113 goto _output_error;
114 length += *ip++;
115 }
116
117 /* copy repeated sequence */
118 if (unlikely((op - ref) < STEPSIZE)) {
119#if LZ4_ARCH64
120 int dec64 = dec64table[op - ref];
121#else
122 const int dec64 = 0;
123#endif
124 op[0] = ref[0];
125 op[1] = ref[1];
126 op[2] = ref[2];
127 op[3] = ref[3];
128 op += 4;
129 ref += 4;
130 ref -= dec32table[op-ref];
131 PUT4(ref, op);
132 op += STEPSIZE - 4;
133 ref -= dec64;
134 } else {
135 LZ4_COPYSTEP(ref, op);
136 }
137 cpy = op + length - (STEPSIZE - 4);
138 if (cpy > (oend - COPYLENGTH)) {
139
140 /* Error: request to write beyond destination buffer */
141 if (cpy > oend)
142 goto _output_error;
143#if LZ4_ARCH64
144 if ((ref + COPYLENGTH) > oend)
145#else
146 if ((ref + COPYLENGTH) > oend ||
147 (op + COPYLENGTH) > oend)
148#endif
149 goto _output_error;
150 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
151 while (op < cpy)
152 *op++ = *ref++;
153 op = cpy;
154 /*
155 * Check EOF (should never happen, since last 5 bytes
156 * are supposed to be literals)
157 */
158 if (op == oend)
159 goto _output_error;
160 continue;
161 }
162 LZ4_SECURECOPY(ref, op, cpy);
163 op = cpy; /* correction */
164 }
165 /* end of decoding */
166 return (int) (((char *)ip) - source);
167
168 /* write overflow error detected */
169_output_error:
170 return -1;
171}
172
173static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
174 int isize, size_t maxoutputsize)
175{
176 const BYTE *ip = (const BYTE *) source;
177 const BYTE *const iend = ip + isize;
178 const BYTE *ref;
179
180
181 BYTE *op = (BYTE *) dest;
182 BYTE * const oend = op + maxoutputsize;
183 BYTE *cpy;
184
185 /* Main Loop */
186 while (ip < iend) {
187
188 unsigned token;
189 size_t length;
190
191 /* get runlength */
192 token = *ip++;
193 length = (token >> ML_BITS);
194 if (length == RUN_MASK) {
195 int s = 255;
196 while ((ip < iend) && (s == 255)) {
197 s = *ip++;
198 if (unlikely(length > (size_t)(length + s)))
199 goto _output_error;
200 length += s;
201 }
202 }
203 /* copy literals */
204 cpy = op + length;
205 if ((cpy > oend - COPYLENGTH) ||
206 (ip + length > iend - COPYLENGTH)) {
207
208 if (cpy > oend)
209 goto _output_error;/* writes beyond buffer */
210
211 if (ip + length != iend)
212 goto _output_error;/*
213 * Error: LZ4 format requires
214 * to consume all input
215 * at this stage
216 */
217 memcpy(op, ip, length);
218 op += length;
219 break;/* Necessarily EOF, due to parsing restrictions */
220 }
221 LZ4_WILDCOPY(ip, op, cpy);
222 ip -= (op - cpy);
223 op = cpy;
224
225 /* get offset */
226 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
227 ip += 2;
228 if (ref < (BYTE * const) dest)
229 goto _output_error;
230 /*
231 * Error : offset creates reference
232 * outside of destination buffer
233 */
234
235 /* get matchlength */
236 length = (token & ML_MASK);
237 if (length == ML_MASK) {
238 while (ip < iend) {
239 int s = *ip++;
240 if (unlikely(length > (size_t)(length + s)))
241 goto _output_error;
242 length += s;
243 if (s == 255)
244 continue;
245 break;
246 }
247 }
248
249 /* copy repeated sequence */
250 if (unlikely((op - ref) < STEPSIZE)) {
251#if LZ4_ARCH64
252 int dec64 = dec64table[op - ref];
253#else
254 const int dec64 = 0;
255#endif
256 op[0] = ref[0];
257 op[1] = ref[1];
258 op[2] = ref[2];
259 op[3] = ref[3];
260 op += 4;
261 ref += 4;
262 ref -= dec32table[op - ref];
263 PUT4(ref, op);
264 op += STEPSIZE - 4;
265 ref -= dec64;
266 } else {
267 LZ4_COPYSTEP(ref, op);
268 }
269 cpy = op + length - (STEPSIZE-4);
270 if (cpy > oend - COPYLENGTH) {
271 if (cpy > oend)
272 goto _output_error; /* write outside of buf */
273#if LZ4_ARCH64
274 if ((ref + COPYLENGTH) > oend)
275#else
276 if ((ref + COPYLENGTH) > oend ||
277 (op + COPYLENGTH) > oend)
278#endif
279 goto _output_error;
280 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
281 while (op < cpy)
282 *op++ = *ref++;
283 op = cpy;
284 /*
285 * Check EOF (should never happen, since last 5 bytes
286 * are supposed to be literals)
287 */
288 if (op == oend)
289 goto _output_error;
290 continue;
291 }
292 LZ4_SECURECOPY(ref, op, cpy);
293 op = cpy; /* correction */
294 }
295 /* end of decoding */
296 return (int) (((char *) op) - dest);
297
298 /* write overflow error detected */
299_output_error:
300 return -1;
301}
302
303int lz4_decompress(const unsigned char *src, size_t *src_len,
304 unsigned char *dest, size_t actual_dest_len)
305{
306 int ret = -1;
307 int input_len = 0;
308
309 input_len = lz4_uncompress(src, dest, actual_dest_len);
310 if (input_len < 0)
311 goto exit_0;
312 *src_len = input_len;
313
314 return 0;
315exit_0:
316 return ret;
317}
318#ifndef STATIC
319EXPORT_SYMBOL(lz4_decompress);
320#endif
321
322int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
323 unsigned char *dest, size_t *dest_len)
324{
325 int ret = -1;
326 int out_len = 0;
327
328 out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
329 *dest_len);
330 if (out_len < 0)
331 goto exit_0;
332 *dest_len = out_len;
333
334 return 0;
335exit_0:
336 return ret;
337}
338#ifndef STATIC
339EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);
340
341MODULE_LICENSE("Dual BSD/GPL");
342MODULE_DESCRIPTION("LZ4 Decompressor");
343#endif
1/*
2 * LZ4 - Fast LZ compression algorithm
3 * Copyright (C) 2011 - 2016, Yann Collet.
4 * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php)
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
15 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
18 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 * You can contact the author at :
26 * - LZ4 homepage : http://www.lz4.org
27 * - LZ4 source repository : https://github.com/lz4/lz4
28 *
29 * Changed for kernel usage by:
30 * Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
31 */
32
33/*-************************************
34 * Dependencies
35 **************************************/
36#include <linux/lz4.h>
37#include "lz4defs.h"
38#include <linux/init.h>
39#include <linux/module.h>
40#include <linux/kernel.h>
41#include <linux/unaligned.h>
42
43/*-*****************************
44 * Decompression functions
45 *******************************/
46
47#define DEBUGLOG(l, ...) {} /* disabled */
48
49#ifndef assert
50#define assert(condition) ((void)0)
51#endif
52
53/*
54 * LZ4_decompress_generic() :
55 * This generic decompression function covers all use cases.
56 * It shall be instantiated several times, using different sets of directives.
57 * Note that it is important for performance that this function really get inlined,
58 * in order to remove useless branches during compilation optimization.
59 */
60static FORCE_INLINE int LZ4_decompress_generic(
61 const char * const src,
62 char * const dst,
63 int srcSize,
64 /*
65 * If endOnInput == endOnInputSize,
66 * this value is `dstCapacity`
67 */
68 int outputSize,
69 /* endOnOutputSize, endOnInputSize */
70 endCondition_directive endOnInput,
71 /* full, partial */
72 earlyEnd_directive partialDecoding,
73 /* noDict, withPrefix64k, usingExtDict */
74 dict_directive dict,
75 /* always <= dst, == dst when no prefix */
76 const BYTE * const lowPrefix,
77 /* only if dict == usingExtDict */
78 const BYTE * const dictStart,
79 /* note : = 0 if noDict */
80 const size_t dictSize
81 )
82{
83 const BYTE *ip = (const BYTE *) src;
84 const BYTE * const iend = ip + srcSize;
85
86 BYTE *op = (BYTE *) dst;
87 BYTE * const oend = op + outputSize;
88 BYTE *cpy;
89
90 const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
91 static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
92 static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
93
94 const int safeDecode = (endOnInput == endOnInputSize);
95 const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
96
97 /* Set up the "end" pointers for the shortcut. */
98 const BYTE *const shortiend = iend -
99 (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
100 const BYTE *const shortoend = oend -
101 (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
102
103 DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
104 srcSize, outputSize);
105
106 /* Special cases */
107 assert(lowPrefix <= op);
108 assert(src != NULL);
109
110 /* Empty output buffer */
111 if ((endOnInput) && (unlikely(outputSize == 0)))
112 return ((srcSize == 1) && (*ip == 0)) ? 0 : -1;
113
114 if ((!endOnInput) && (unlikely(outputSize == 0)))
115 return (*ip == 0 ? 1 : -1);
116
117 if ((endOnInput) && unlikely(srcSize == 0))
118 return -1;
119
120 /* Main Loop : decode sequences */
121 while (1) {
122 size_t length;
123 const BYTE *match;
124 size_t offset;
125
126 /* get literal length */
127 unsigned int const token = *ip++;
128 length = token>>ML_BITS;
129
130 /* ip < iend before the increment */
131 assert(!endOnInput || ip <= iend);
132
133 /*
134 * A two-stage shortcut for the most common case:
135 * 1) If the literal length is 0..14, and there is enough
136 * space, enter the shortcut and copy 16 bytes on behalf
137 * of the literals (in the fast mode, only 8 bytes can be
138 * safely copied this way).
139 * 2) Further if the match length is 4..18, copy 18 bytes
140 * in a similar manner; but we ensure that there's enough
141 * space in the output for those 18 bytes earlier, upon
142 * entering the shortcut (in other words, there is a
143 * combined check for both stages).
144 *
145 * The & in the likely() below is intentionally not && so that
146 * some compilers can produce better parallelized runtime code
147 */
148 if ((endOnInput ? length != RUN_MASK : length <= 8)
149 /*
150 * strictly "less than" on input, to re-enter
151 * the loop with at least one byte
152 */
153 && likely((endOnInput ? ip < shortiend : 1) &
154 (op <= shortoend))) {
155 /* Copy the literals */
156 LZ4_memcpy(op, ip, endOnInput ? 16 : 8);
157 op += length; ip += length;
158
159 /*
160 * The second stage:
161 * prepare for match copying, decode full info.
162 * If it doesn't work out, the info won't be wasted.
163 */
164 length = token & ML_MASK; /* match length */
165 offset = LZ4_readLE16(ip);
166 ip += 2;
167 match = op - offset;
168 assert(match <= op); /* check overflow */
169
170 /* Do not deal with overlapping matches. */
171 if ((length != ML_MASK) &&
172 (offset >= 8) &&
173 (dict == withPrefix64k || match >= lowPrefix)) {
174 /* Copy the match. */
175 LZ4_memcpy(op + 0, match + 0, 8);
176 LZ4_memcpy(op + 8, match + 8, 8);
177 LZ4_memcpy(op + 16, match + 16, 2);
178 op += length + MINMATCH;
179 /* Both stages worked, load the next token. */
180 continue;
181 }
182
183 /*
184 * The second stage didn't work out, but the info
185 * is ready. Propel it right to the point of match
186 * copying.
187 */
188 goto _copy_match;
189 }
190
191 /* decode literal length */
192 if (length == RUN_MASK) {
193 unsigned int s;
194
195 if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
196 /* overflow detection */
197 goto _output_error;
198 }
199 do {
200 s = *ip++;
201 length += s;
202 } while (likely(endOnInput
203 ? ip < iend - RUN_MASK
204 : 1) & (s == 255));
205
206 if ((safeDecode)
207 && unlikely((uptrval)(op) +
208 length < (uptrval)(op))) {
209 /* overflow detection */
210 goto _output_error;
211 }
212 if ((safeDecode)
213 && unlikely((uptrval)(ip) +
214 length < (uptrval)(ip))) {
215 /* overflow detection */
216 goto _output_error;
217 }
218 }
219
220 /* copy literals */
221 cpy = op + length;
222 LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
223
224 if (((endOnInput) && ((cpy > oend - MFLIMIT)
225 || (ip + length > iend - (2 + 1 + LASTLITERALS))))
226 || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
227 if (partialDecoding) {
228 if (cpy > oend) {
229 /*
230 * Partial decoding :
231 * stop in the middle of literal segment
232 */
233 cpy = oend;
234 length = oend - op;
235 }
236 if ((endOnInput)
237 && (ip + length > iend)) {
238 /*
239 * Error :
240 * read attempt beyond
241 * end of input buffer
242 */
243 goto _output_error;
244 }
245 } else {
246 if ((!endOnInput)
247 && (cpy != oend)) {
248 /*
249 * Error :
250 * block decoding must
251 * stop exactly there
252 */
253 goto _output_error;
254 }
255 if ((endOnInput)
256 && ((ip + length != iend)
257 || (cpy > oend))) {
258 /*
259 * Error :
260 * input must be consumed
261 */
262 goto _output_error;
263 }
264 }
265
266 /*
267 * supports overlapping memory regions; only matters
268 * for in-place decompression scenarios
269 */
270 LZ4_memmove(op, ip, length);
271 ip += length;
272 op += length;
273
274 /* Necessarily EOF 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 }
287
288 /* get offset */
289 offset = LZ4_readLE16(ip);
290 ip += 2;
291 match = op - offset;
292
293 /* get matchlength */
294 length = token & ML_MASK;
295
296_copy_match:
297 if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
298 /* Error : offset outside buffers */
299 goto _output_error;
300 }
301
302 /* costs ~1%; silence an msan warning when offset == 0 */
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);
310
311 LZ4_write32(op, (U32)offset);
312 }
313
314 if (length == ML_MASK) {
315 unsigned int s;
316
317 do {
318 s = *ip++;
319
320 if ((endOnInput) && (ip > iend - LASTLITERALS))
321 goto _output_error;
322
323 length += s;
324 } while (s == 255);
325
326 if ((safeDecode)
327 && unlikely(
328 (uptrval)(op) + length < (uptrval)op)) {
329 /* overflow detection */
330 goto _output_error;
331 }
332 }
333
334 length += MINMATCH;
335
336 /* match starting within external dictionary */
337 if ((dict == usingExtDict) && (match < lowPrefix)) {
338 if (unlikely(op + length > oend - LASTLITERALS)) {
339 /* doesn't respect parsing restriction */
340 if (!partialDecoding)
341 goto _output_error;
342 length = min(length, (size_t)(oend - op));
343 }
344
345 if (length <= (size_t)(lowPrefix - match)) {
346 /*
347 * match fits entirely within external
348 * dictionary : just copy
349 */
350 memmove(op, dictEnd - (lowPrefix - match),
351 length);
352 op += length;
353 } else {
354 /*
355 * match stretches into both external
356 * dictionary and current block
357 */
358 size_t const copySize = (size_t)(lowPrefix - match);
359 size_t const restSize = length - copySize;
360
361 LZ4_memcpy(op, dictEnd - copySize, copySize);
362 op += copySize;
363 if (restSize > (size_t)(op - lowPrefix)) {
364 /* overlap copy */
365 BYTE * const endOfMatch = op + restSize;
366 const BYTE *copyFrom = lowPrefix;
367
368 while (op < endOfMatch)
369 *op++ = *copyFrom++;
370 } else {
371 LZ4_memcpy(op, lowPrefix, restSize);
372 op += restSize;
373 }
374 }
375 continue;
376 }
377
378 /* copy match within block */
379 cpy = op + length;
380
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;
391
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)) {
406 op[0] = match[0];
407 op[1] = match[1];
408 op[2] = match[2];
409 op[3] = match[3];
410 match += inc32table[offset];
411 LZ4_memcpy(op + 4, match, 4);
412 match -= dec64table[offset];
413 } else {
414 LZ4_copy8(op, match);
415 match += 8;
416 }
417
418 op += 8;
419
420 if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
421 BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
422
423 if (cpy > oend - LASTLITERALS) {
424 /*
425 * Error : last LASTLITERALS bytes
426 * must be literals (uncompressed)
427 */
428 goto _output_error;
429 }
430
431 if (op < oCopyLimit) {
432 LZ4_wildCopy(op, match, oCopyLimit);
433 match += oCopyLimit - op;
434 op = oCopyLimit;
435 }
436 while (op < cpy)
437 *op++ = *match++;
438 } else {
439 LZ4_copy8(op, match);
440 if (length > 16)
441 LZ4_wildCopy(op + 8, match + 8, cpy);
442 }
443 op = cpy; /* wildcopy correction */
444 }
445
446 /* end of decoding */
447 if (endOnInput) {
448 /* Nb of output bytes decoded */
449 return (int) (((char *)op) - dst);
450 } else {
451 /* Nb of input bytes read */
452 return (int) (((const char *)ip) - src);
453 }
454
455 /* Overflow error detected */
456_output_error:
457 return (int) (-(((const char *)ip) - src)) - 1;
458}
459
460int LZ4_decompress_safe(const char *source, char *dest,
461 int compressedSize, int maxDecompressedSize)
462{
463 return LZ4_decompress_generic(source, dest,
464 compressedSize, maxDecompressedSize,
465 endOnInputSize, decode_full_block,
466 noDict, (BYTE *)dest, NULL, 0);
467}
468
469int LZ4_decompress_safe_partial(const char *src, char *dst,
470 int compressedSize, int targetOutputSize, int dstCapacity)
471{
472 dstCapacity = min(targetOutputSize, dstCapacity);
473 return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
474 endOnInputSize, partial_decode,
475 noDict, (BYTE *)dst, NULL, 0);
476}
477
478int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
479{
480 return LZ4_decompress_generic(source, dest, 0, originalSize,
481 endOnOutputSize, decode_full_block,
482 withPrefix64k,
483 (BYTE *)dest - 64 * KB, NULL, 0);
484}
485
486/* ===== Instantiate a few more decoding cases, used more than once. ===== */
487
488static 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
498static 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
510static 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
521static 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 */
537static FORCE_INLINE
538int 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
550static FORCE_INLINE
551int 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 ===== */
563
564int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
565 const char *dictionary, int dictSize)
566{
567 LZ4_streamDecode_t_internal *lz4sd =
568 &LZ4_streamDecode->internal_donotuse;
569
570 lz4sd->prefixSize = (size_t) dictSize;
571 lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize;
572 lz4sd->externalDict = NULL;
573 lz4sd->extDictSize = 0;
574 return 1;
575}
576
577/*
578 * *_continue() :
579 * These decoding functions allow decompression of multiple blocks
580 * in "streaming" mode.
581 * Previously decoded blocks must still be available at the memory
582 * position where they were decoded.
583 * If it's not possible, save the relevant part of
584 * decoded data into a safe buffer,
585 * and indicate where it stands using LZ4_setStreamDecode()
586 */
587int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
588 const char *source, char *dest, int compressedSize, int maxOutputSize)
589{
590 LZ4_streamDecode_t_internal *lz4sd =
591 &LZ4_streamDecode->internal_donotuse;
592 int result;
593
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);
599 if (result <= 0)
600 return result;
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;
619 lz4sd->prefixSize += result;
620 lz4sd->prefixEnd += result;
621 } else {
622 /*
623 * The buffer wraps around, or they're
624 * switching to another buffer.
625 */
626 lz4sd->extDictSize = lz4sd->prefixSize;
627 lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
628 result = LZ4_decompress_safe_forceExtDict(source, dest,
629 compressedSize, maxOutputSize,
630 lz4sd->externalDict, lz4sd->extDictSize);
631 if (result <= 0)
632 return result;
633 lz4sd->prefixSize = result;
634 lz4sd->prefixEnd = (BYTE *)dest + result;
635 }
636
637 return result;
638}
639
640int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
641 const char *source, char *dest, int originalSize)
642{
643 LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
644 int result;
645
646 if (lz4sd->prefixSize == 0) {
647 assert(lz4sd->extDictSize == 0);
648 result = LZ4_decompress_fast(source, dest, originalSize);
649 if (result <= 0)
650 return result;
651 lz4sd->prefixSize = 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;
675 }
676 return result;
677}
678
679int LZ4_decompress_safe_usingDict(const char *source, char *dest,
680 int compressedSize, int maxOutputSize,
681 const char *dictStart, int dictSize)
682{
683 if (dictSize == 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);
692 }
693 return LZ4_decompress_safe_forceExtDict(source, dest,
694 compressedSize, maxOutputSize, dictStart, dictSize);
695}
696
697int LZ4_decompress_fast_usingDict(const char *source, char *dest,
698 int originalSize,
699 const char *dictStart, int dictSize)
700{
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);
706}
707
708#ifndef STATIC
709EXPORT_SYMBOL(LZ4_decompress_safe);
710EXPORT_SYMBOL(LZ4_decompress_safe_partial);
711EXPORT_SYMBOL(LZ4_decompress_fast);
712EXPORT_SYMBOL(LZ4_setStreamDecode);
713EXPORT_SYMBOL(LZ4_decompress_safe_continue);
714EXPORT_SYMBOL(LZ4_decompress_fast_continue);
715EXPORT_SYMBOL(LZ4_decompress_safe_usingDict);
716EXPORT_SYMBOL(LZ4_decompress_fast_usingDict);
717
718MODULE_LICENSE("Dual BSD/GPL");
719MODULE_DESCRIPTION("LZ4 decompressor");
720#endif