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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 | |
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 unsigned char *src, size_t *src_len, |
287 | unsigned char *dest, 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(lz4_decompress); |
303 | #endif |
304 | |
305 | int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len, |
306 | unsigned 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(lz4_decompress_unknownoutputsize); |
323 | |
324 | MODULE_LICENSE("Dual BSD/GPL"); |
325 | MODULE_DESCRIPTION("LZ4 Decompressor"); |
326 | #endif |
327 |
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