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 const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
52 static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
55 static int lz4_uncompress(const char *source, char *dest, int osize)
57 const BYTE *ip = (const BYTE *) source;
59 BYTE *op = (BYTE *) dest;
60 BYTE * const oend = op + osize;
69 length = (token >> ML_BITS);
70 if (length == RUN_MASK) {
74 for (; len == 255; length += 255)
76 if (unlikely(length > (size_t)(length + len)))
83 if (unlikely(cpy > oend - COPYLENGTH)) {
85 * Error: not enough place for another match
86 * (min 4) + 5 literals
91 memcpy(op, ip, length);
95 LZ4_WILDCOPY(ip, op, cpy);
100 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
103 /* Error: offset create reference outside destination buffer */
104 if (unlikely(ref < (BYTE *const) dest))
107 /* get matchlength */
108 length = token & ML_MASK;
109 if (length == ML_MASK) {
110 for (; *ip == 255; length += 255)
112 if (unlikely(length > (size_t)(length + *ip)))
117 /* copy repeated sequence */
118 if (unlikely((op - ref) < STEPSIZE)) {
120 int dec64 = dec64table[op - ref];
130 ref -= dec32table[op-ref];
135 LZ4_COPYSTEP(ref, op);
137 cpy = op + length - (STEPSIZE - 4);
138 if (cpy > (oend - COPYLENGTH)) {
140 /* Error: request to write beyond destination buffer */
143 if ((ref + COPYLENGTH) > oend ||
144 (op + COPYLENGTH) > oend)
146 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
151 * Check EOF (should never happen, since last 5 bytes
152 * are supposed to be literals)
158 LZ4_SECURECOPY(ref, op, cpy);
159 op = cpy; /* correction */
161 /* end of decoding */
162 return (int) (((char *)ip) - source);
164 /* write overflow error detected */
169 static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
170 int isize, size_t maxoutputsize)
172 const BYTE *ip = (const BYTE *) source;
173 const BYTE *const iend = ip + isize;
177 BYTE *op = (BYTE *) dest;
178 BYTE * const oend = op + maxoutputsize;
189 length = (token >> ML_BITS);
190 if (length == RUN_MASK) {
192 while ((ip < iend) && (s == 255)) {
194 if (unlikely(length > (size_t)(length + s)))
201 if ((cpy > oend - COPYLENGTH) ||
202 (ip + length > iend - COPYLENGTH)) {
205 goto _output_error;/* writes beyond buffer */
207 if (ip + length != iend)
208 goto _output_error;/*
209 * Error: LZ4 format requires
210 * to consume all input
213 memcpy(op, ip, length);
215 break;/* Necessarily EOF, due to parsing restrictions */
217 LZ4_WILDCOPY(ip, op, cpy);
222 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
224 if (ref < (BYTE * const) dest)
227 * Error : offset creates reference
228 * outside of destination buffer
231 /* get matchlength */
232 length = (token & ML_MASK);
233 if (length == ML_MASK) {
236 if (unlikely(length > (size_t)(length + s)))
245 /* copy repeated sequence */
246 if (unlikely((op - ref) < STEPSIZE)) {
248 int dec64 = dec64table[op - ref];
258 ref -= dec32table[op - ref];
263 LZ4_COPYSTEP(ref, op);
265 cpy = op + length - (STEPSIZE-4);
266 if (cpy > oend - COPYLENGTH) {
268 goto _output_error; /* write outside of buf */
270 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
275 * Check EOF (should never happen, since last 5 bytes
276 * are supposed to be literals)
282 LZ4_SECURECOPY(ref, op, cpy);
283 op = cpy; /* correction */
285 /* end of decoding */
286 return (int) (((char *) op) - dest);
288 /* write overflow error detected */
293 int lz4_decompress(const unsigned char *src, size_t *src_len,
294 unsigned char *dest, size_t actual_dest_len)
299 input_len = lz4_uncompress(src, dest, actual_dest_len);
302 *src_len = input_len;
309 EXPORT_SYMBOL(lz4_decompress);
312 int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
313 unsigned char *dest, size_t *dest_len)
318 out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
329 EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);
331 MODULE_LICENSE("Dual BSD/GPL");
332 MODULE_DESCRIPTION("LZ4 Decompressor");