Commit | Line | Data |
---|---|---|
cffb78b0 KL |
1 | /* |
2 | * LZ4 Decompressor for Linux kernel | |
3 | * | |
e76e1fdf | 4 | * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com> |
cffb78b0 KL |
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 | ||
50 | static int lz4_uncompress(const char *source, char *dest, int osize) | |
51 | { | |
52 | const BYTE *ip = (const BYTE *) source; | |
53 | const BYTE *ref; | |
54 | BYTE *op = (BYTE *) dest; | |
55 | BYTE * const oend = op + osize; | |
56 | BYTE *cpy; | |
57 | unsigned token; | |
58 | size_t length; | |
59 | size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; | |
60 | #if LZ4_ARCH64 | |
61 | size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; | |
62 | #endif | |
63 | ||
64 | while (1) { | |
65 | ||
66 | /* get runlength */ | |
67 | token = *ip++; | |
68 | length = (token >> ML_BITS); | |
69 | if (length == RUN_MASK) { | |
70 | size_t len; | |
71 | ||
72 | len = *ip++; | |
73 | for (; len == 255; length += 255) | |
74 | len = *ip++; | |
75 | length += len; | |
76 | } | |
77 | ||
78 | /* copy literals */ | |
79 | cpy = op + length; | |
80 | if (unlikely(cpy > oend - COPYLENGTH)) { | |
81 | /* | |
82 | * Error: not enough place for another match | |
83 | * (min 4) + 5 literals | |
84 | */ | |
85 | if (cpy != oend) | |
86 | goto _output_error; | |
87 | ||
88 | memcpy(op, ip, length); | |
89 | ip += length; | |
90 | break; /* EOF */ | |
91 | } | |
92 | LZ4_WILDCOPY(ip, op, cpy); | |
93 | ip -= (op - cpy); | |
94 | op = cpy; | |
95 | ||
96 | /* get offset */ | |
97 | LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); | |
98 | ip += 2; | |
99 | ||
100 | /* Error: offset create reference outside destination buffer */ | |
101 | if (unlikely(ref < (BYTE *const) dest)) | |
102 | goto _output_error; | |
103 | ||
104 | /* get matchlength */ | |
105 | length = token & ML_MASK; | |
106 | if (length == ML_MASK) { | |
107 | for (; *ip == 255; length += 255) | |
108 | ip++; | |
109 | length += *ip++; | |
110 | } | |
111 | ||
112 | /* copy repeated sequence */ | |
113 | if (unlikely((op - ref) < STEPSIZE)) { | |
114 | #if LZ4_ARCH64 | |
115 | size_t dec64 = dec64table[op - ref]; | |
116 | #else | |
117 | const int dec64 = 0; | |
118 | #endif | |
119 | op[0] = ref[0]; | |
120 | op[1] = ref[1]; | |
121 | op[2] = ref[2]; | |
122 | op[3] = ref[3]; | |
123 | op += 4; | |
124 | ref += 4; | |
125 | ref -= dec32table[op-ref]; | |
126 | PUT4(ref, op); | |
127 | op += STEPSIZE - 4; | |
128 | ref -= dec64; | |
129 | } else { | |
130 | LZ4_COPYSTEP(ref, op); | |
131 | } | |
132 | cpy = op + length - (STEPSIZE - 4); | |
133 | if (cpy > (oend - COPYLENGTH)) { | |
134 | ||
135 | /* Error: request to write beyond destination buffer */ | |
136 | if (cpy > oend) | |
137 | goto _output_error; | |
138 | LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); | |
139 | while (op < cpy) | |
140 | *op++ = *ref++; | |
141 | op = cpy; | |
142 | /* | |
143 | * Check EOF (should never happen, since last 5 bytes | |
144 | * are supposed to be literals) | |
145 | */ | |
146 | if (op == oend) | |
147 | goto _output_error; | |
148 | continue; | |
149 | } | |
150 | LZ4_SECURECOPY(ref, op, cpy); | |
151 | op = cpy; /* correction */ | |
152 | } | |
153 | /* end of decoding */ | |
154 | return (int) (((char *)ip) - source); | |
155 | ||
156 | /* write overflow error detected */ | |
157 | _output_error: | |
158 | return (int) (-(((char *)ip) - source)); | |
159 | } | |
160 | ||
161 | static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, | |
162 | int isize, size_t maxoutputsize) | |
163 | { | |
164 | const BYTE *ip = (const BYTE *) source; | |
165 | const BYTE *const iend = ip + isize; | |
166 | const BYTE *ref; | |
167 | ||
168 | ||
169 | BYTE *op = (BYTE *) dest; | |
170 | BYTE * const oend = op + maxoutputsize; | |
171 | BYTE *cpy; | |
172 | ||
173 | size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; | |
174 | #if LZ4_ARCH64 | |
175 | size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; | |
176 | #endif | |
177 | ||
178 | /* Main Loop */ | |
179 | while (ip < iend) { | |
180 | ||
181 | unsigned token; | |
182 | size_t length; | |
183 | ||
184 | /* get runlength */ | |
185 | token = *ip++; | |
186 | length = (token >> ML_BITS); | |
187 | if (length == RUN_MASK) { | |
188 | int s = 255; | |
189 | while ((ip < iend) && (s == 255)) { | |
190 | s = *ip++; | |
191 | length += s; | |
192 | } | |
193 | } | |
194 | /* copy literals */ | |
195 | cpy = op + length; | |
196 | if ((cpy > oend - COPYLENGTH) || | |
197 | (ip + length > iend - COPYLENGTH)) { | |
198 | ||
199 | if (cpy > oend) | |
200 | goto _output_error;/* writes beyond buffer */ | |
201 | ||
202 | if (ip + length != iend) | |
203 | goto _output_error;/* | |
204 | * Error: LZ4 format requires | |
205 | * to consume all input | |
206 | * at this stage | |
207 | */ | |
208 | memcpy(op, ip, length); | |
209 | op += length; | |
210 | break;/* Necessarily EOF, due to parsing restrictions */ | |
211 | } | |
212 | LZ4_WILDCOPY(ip, op, cpy); | |
213 | ip -= (op - cpy); | |
214 | op = cpy; | |
215 | ||
216 | /* get offset */ | |
217 | LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); | |
218 | ip += 2; | |
219 | if (ref < (BYTE * const) dest) | |
220 | goto _output_error; | |
221 | /* | |
222 | * Error : offset creates reference | |
223 | * outside of destination buffer | |
224 | */ | |
225 | ||
226 | /* get matchlength */ | |
227 | length = (token & ML_MASK); | |
228 | if (length == ML_MASK) { | |
229 | while (ip < iend) { | |
230 | int s = *ip++; | |
231 | length += s; | |
232 | if (s == 255) | |
233 | continue; | |
234 | break; | |
235 | } | |
236 | } | |
237 | ||
238 | /* copy repeated sequence */ | |
239 | if (unlikely((op - ref) < STEPSIZE)) { | |
240 | #if LZ4_ARCH64 | |
241 | size_t dec64 = dec64table[op - ref]; | |
242 | #else | |
243 | const int dec64 = 0; | |
244 | #endif | |
245 | op[0] = ref[0]; | |
246 | op[1] = ref[1]; | |
247 | op[2] = ref[2]; | |
248 | op[3] = ref[3]; | |
249 | op += 4; | |
250 | ref += 4; | |
251 | ref -= dec32table[op - ref]; | |
252 | PUT4(ref, op); | |
253 | op += STEPSIZE - 4; | |
254 | ref -= dec64; | |
255 | } else { | |
256 | LZ4_COPYSTEP(ref, op); | |
257 | } | |
258 | cpy = op + length - (STEPSIZE-4); | |
259 | if (cpy > oend - COPYLENGTH) { | |
260 | if (cpy > oend) | |
261 | goto _output_error; /* write outside of buf */ | |
262 | ||
263 | LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); | |
264 | while (op < cpy) | |
265 | *op++ = *ref++; | |
266 | op = cpy; | |
267 | /* | |
268 | * Check EOF (should never happen, since last 5 bytes | |
269 | * are supposed to be literals) | |
270 | */ | |
271 | if (op == oend) | |
272 | goto _output_error; | |
273 | continue; | |
274 | } | |
275 | LZ4_SECURECOPY(ref, op, cpy); | |
276 | op = cpy; /* correction */ | |
277 | } | |
278 | /* end of decoding */ | |
279 | return (int) (((char *) op) - dest); | |
280 | ||
281 | /* write overflow error detected */ | |
282 | _output_error: | |
283 | return (int) (-(((char *) ip) - source)); | |
284 | } | |
285 | ||
286 | int lz4_decompress(const char *src, size_t *src_len, char *dest, | |
287 | size_t actual_dest_len) | |
288 | { | |
289 | int ret = -1; | |
290 | int input_len = 0; | |
291 | ||
292 | input_len = lz4_uncompress(src, dest, actual_dest_len); | |
293 | if (input_len < 0) | |
294 | goto exit_0; | |
295 | *src_len = input_len; | |
296 | ||
297 | return 0; | |
298 | exit_0: | |
299 | return ret; | |
300 | } | |
301 | #ifndef STATIC | |
302 | EXPORT_SYMBOL_GPL(lz4_decompress); | |
303 | #endif | |
304 | ||
305 | int lz4_decompress_unknownoutputsize(const char *src, size_t src_len, | |
306 | char *dest, size_t *dest_len) | |
307 | { | |
308 | int ret = -1; | |
309 | int out_len = 0; | |
310 | ||
311 | out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len, | |
312 | *dest_len); | |
313 | if (out_len < 0) | |
314 | goto exit_0; | |
315 | *dest_len = out_len; | |
316 | ||
317 | return 0; | |
318 | exit_0: | |
319 | return ret; | |
320 | } | |
321 | #ifndef STATIC | |
322 | EXPORT_SYMBOL_GPL(lz4_decompress_unknownoutputsize); | |
323 | ||
324 | MODULE_LICENSE("GPL"); | |
325 | MODULE_DESCRIPTION("LZ4 Decompressor"); | |
326 | #endif |