2 * LZ4 Decompressor for Linux kernel
4 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
6 * Based on LZ4 implementation by Yann Collet.
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)
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions are
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
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.
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/
41 #include <linux/module.h>
42 #include <linux/kernel.h>
44 #include <linux/lz4.h>
46 #include <asm/unaligned.h>
50 static int lz4_uncompress(const char *source, char *dest, int osize)
52 const BYTE *ip = (const BYTE *) source;
54 BYTE *op = (BYTE *) dest;
55 BYTE * const oend = op + osize;
59 size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
61 size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
68 length = (token >> ML_BITS);
69 if (length == RUN_MASK) {
73 for (; len == 255; length += 255)
80 if (unlikely(cpy > oend - COPYLENGTH)) {
82 * Error: not enough place for another match
83 * (min 4) + 5 literals
88 memcpy(op, ip, length);
92 LZ4_WILDCOPY(ip, op, cpy);
97 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
100 /* Error: offset create reference outside destination buffer */
101 if (unlikely(ref < (BYTE *const) dest))
104 /* get matchlength */
105 length = token & ML_MASK;
106 if (length == ML_MASK) {
107 for (; *ip == 255; length += 255)
112 /* copy repeated sequence */
113 if (unlikely((op - ref) < STEPSIZE)) {
115 size_t dec64 = dec64table[op - ref];
125 ref -= dec32table[op-ref];
130 LZ4_COPYSTEP(ref, op);
132 cpy = op + length - (STEPSIZE - 4);
133 if (cpy > (oend - COPYLENGTH)) {
135 /* Error: request to write beyond destination buffer */
138 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
143 * Check EOF (should never happen, since last 5 bytes
144 * are supposed to be literals)
150 LZ4_SECURECOPY(ref, op, cpy);
151 op = cpy; /* correction */
153 /* end of decoding */
154 return (int) (((char *)ip) - source);
156 /* write overflow error detected */
158 return (int) (-(((char *)ip) - source));
161 static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
162 int isize, size_t maxoutputsize)
164 const BYTE *ip = (const BYTE *) source;
165 const BYTE *const iend = ip + isize;
169 BYTE *op = (BYTE *) dest;
170 BYTE * const oend = op + maxoutputsize;
173 size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
175 size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
186 length = (token >> ML_BITS);
187 if (length == RUN_MASK) {
189 while ((ip < iend) && (s == 255)) {
196 if ((cpy > oend - COPYLENGTH) ||
197 (ip + length > iend - COPYLENGTH)) {
200 goto _output_error;/* writes beyond buffer */
202 if (ip + length != iend)
203 goto _output_error;/*
204 * Error: LZ4 format requires
205 * to consume all input
208 memcpy(op, ip, length);
210 break;/* Necessarily EOF, due to parsing restrictions */
212 LZ4_WILDCOPY(ip, op, cpy);
217 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
219 if (ref < (BYTE * const) dest)
222 * Error : offset creates reference
223 * outside of destination buffer
226 /* get matchlength */
227 length = (token & ML_MASK);
228 if (length == ML_MASK) {
238 /* copy repeated sequence */
239 if (unlikely((op - ref) < STEPSIZE)) {
241 size_t dec64 = dec64table[op - ref];
251 ref -= dec32table[op - ref];
256 LZ4_COPYSTEP(ref, op);
258 cpy = op + length - (STEPSIZE-4);
259 if (cpy > oend - COPYLENGTH) {
261 goto _output_error; /* write outside of buf */
263 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
268 * Check EOF (should never happen, since last 5 bytes
269 * are supposed to be literals)
275 LZ4_SECURECOPY(ref, op, cpy);
276 op = cpy; /* correction */
278 /* end of decoding */
279 return (int) (((char *) op) - dest);
281 /* write overflow error detected */
283 return (int) (-(((char *) ip) - source));
286 int lz4_decompress(const unsigned char *src, size_t *src_len,
287 unsigned char *dest, size_t actual_dest_len)
292 input_len = lz4_uncompress(src, dest, actual_dest_len);
295 *src_len = input_len;
302 EXPORT_SYMBOL(lz4_decompress);
305 int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
306 unsigned char *dest, size_t *dest_len)
311 out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
322 EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);
324 MODULE_LICENSE("Dual BSD/GPL");
325 MODULE_DESCRIPTION("LZ4 Decompressor");