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source: vbox/trunk/src/libs/liblzf-3.4/lzf_d.c@ 45633

Last change on this file since 45633 was 17027, checked in by vboxsync, 16 years ago

liblzf-3.4: exporting (in progress).

File size: 4.3 KB
Line 
1/*
2 * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de>
3 *
4 * Redistribution and use in source and binary forms, with or without modifica-
5 * tion, are permitted provided that the following conditions are met:
6 *
7 * 1. Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 *
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
15 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
16 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
17 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
18 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
20 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
21 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
22 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
23 * OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 * Alternatively, the contents of this file may be used under the terms of
26 * the GNU General Public License ("GPL") version 2 or any later version,
27 * in which case the provisions of the GPL are applicable instead of
28 * the above. If you wish to allow the use of your version of this file
29 * only under the terms of the GPL and not to allow others to use your
30 * version of this file under the BSD license, indicate your decision
31 * by deleting the provisions above and replace them with the notice
32 * and other provisions required by the GPL. If you do not delete the
33 * provisions above, a recipient may use your version of this file under
34 * either the BSD or the GPL.
35 */
36
37#include "lzfP.h"
38#ifdef VBOX
39# include "lzf.h" /* need the prototype */
40#endif
41
42#if AVOID_ERRNO
43# define SET_ERRNO(n)
44#else
45# include <errno.h>
46# define SET_ERRNO(n) errno = (n)
47#endif
48
49#if (__i386 || __amd64) && __GNUC__ >= 3
50# define lzf_movsb(dst, src, len) \
51 asm ("rep movsb" \
52 : "=D" (dst), "=S" (src), "=c" (len) \
53 : "0" (dst), "1" (src), "2" (len));
54#endif
55
56unsigned int
57lzf_decompress (const void *const in_data, unsigned int in_len,
58 void *out_data, unsigned int out_len)
59{
60 u8 const *ip = (const u8 *)in_data;
61 u8 *op = (u8 *)out_data;
62 u8 const *const in_end = ip + in_len;
63 u8 *const out_end = op + out_len;
64
65 do
66 {
67 unsigned int ctrl = *ip++;
68
69 if (ctrl < (1 << 5)) /* literal run */
70 {
71 ctrl++;
72
73 if (op + ctrl > out_end)
74 {
75 SET_ERRNO (E2BIG);
76 return 0;
77 }
78
79#if CHECK_INPUT
80 if (ip + ctrl > in_end)
81 {
82 SET_ERRNO (EINVAL);
83 return 0;
84 }
85#endif
86
87#ifdef lzf_movsb
88 lzf_movsb (op, ip, ctrl);
89#else
90 do
91 *op++ = *ip++;
92 while (--ctrl);
93#endif
94 }
95 else /* back reference */
96 {
97 unsigned int len = ctrl >> 5;
98
99 u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;
100
101#if CHECK_INPUT
102 if (ip >= in_end)
103 {
104 SET_ERRNO (EINVAL);
105 return 0;
106 }
107#endif
108 if (len == 7)
109 {
110 len += *ip++;
111#if CHECK_INPUT
112 if (ip >= in_end)
113 {
114 SET_ERRNO (EINVAL);
115 return 0;
116 }
117#endif
118 }
119
120 ref -= *ip++;
121
122 if (op + len + 2 > out_end)
123 {
124 SET_ERRNO (E2BIG);
125 return 0;
126 }
127
128 if (ref < (u8 *)out_data)
129 {
130 SET_ERRNO (EINVAL);
131 return 0;
132 }
133
134#ifdef lzf_movsb
135 len += 2;
136 lzf_movsb (op, ref, len);
137#else
138 *op++ = *ref++;
139 *op++ = *ref++;
140
141 do
142 *op++ = *ref++;
143 while (--len);
144#endif
145 }
146 }
147 while (ip < in_end);
148
149 return op - (u8 *)out_data;
150}
151
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