1/*
2 * Copyright (c) 2000-2010 Marc Alexander Lehmann <[email protected]>
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
39#if AVOID_ERRNO
40# define SET_ERRNO(n)
41#else
42# include <errno.h>
43# define SET_ERRNO(n) errno = (n)
44#endif
45
46#if USE_REP_MOVSB /* small win on amd, big loss on intel */
47#if (__i386 || __amd64) && __GNUC__ >= 3
48# define lzf_movsb(dst, src, len) \
49 asm ("rep movsb" \
50 : "=D" (dst), "=S" (src), "=c" (len) \
51 : "0" (dst), "1" (src), "2" (len));
52#endif
53#endif
54
55#if defined(__GNUC__) && __GNUC__ >= 7
56#pragma GCC diagnostic push
57#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
58#endif
59size_t
60lzf_decompress (const void *const in_data, size_t in_len,
61 void *out_data, size_t out_len)
62{
63 u8 const *ip = (const u8 *)in_data;
64 u8 *op = (u8 *)out_data;
65 u8 const *const in_end = ip + in_len;
66 u8 *const out_end = op + out_len;
67
68 while (ip < in_end)
69 {
70 unsigned int ctrl;
71 ctrl = *ip++;
72
73 if (ctrl < (1 << 5)) /* literal run */
74 {
75 ctrl++;
76
77 if (op + ctrl > out_end)
78 {
79 SET_ERRNO (E2BIG);
80 return 0;
81 }
82
83#if CHECK_INPUT
84 if (ip + ctrl > in_end)
85 {
86 SET_ERRNO (EINVAL);
87 return 0;
88 }
89#endif
90
91#ifdef lzf_movsb
92 lzf_movsb (op, ip, ctrl);
93#else
94 switch (ctrl)
95 {
96 case 32: *op++ = *ip++; case 31: *op++ = *ip++; case 30: *op++ = *ip++; case 29: *op++ = *ip++;
97 case 28: *op++ = *ip++; case 27: *op++ = *ip++; case 26: *op++ = *ip++; case 25: *op++ = *ip++;
98 case 24: *op++ = *ip++; case 23: *op++ = *ip++; case 22: *op++ = *ip++; case 21: *op++ = *ip++;
99 case 20: *op++ = *ip++; case 19: *op++ = *ip++; case 18: *op++ = *ip++; case 17: *op++ = *ip++;
100 case 16: *op++ = *ip++; case 15: *op++ = *ip++; case 14: *op++ = *ip++; case 13: *op++ = *ip++;
101 case 12: *op++ = *ip++; case 11: *op++ = *ip++; case 10: *op++ = *ip++; case 9: *op++ = *ip++;
102 case 8: *op++ = *ip++; case 7: *op++ = *ip++; case 6: *op++ = *ip++; case 5: *op++ = *ip++;
103 case 4: *op++ = *ip++; case 3: *op++ = *ip++; case 2: *op++ = *ip++; case 1: *op++ = *ip++;
104 }
105#endif
106 }
107 else /* back reference */
108 {
109 unsigned int len = ctrl >> 5;
110
111 u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;
112
113#if CHECK_INPUT
114 if (ip >= in_end)
115 {
116 SET_ERRNO (EINVAL);
117 return 0;
118 }
119#endif
120 if (len == 7)
121 {
122 len += *ip++;
123#if CHECK_INPUT
124 if (ip >= in_end)
125 {
126 SET_ERRNO (EINVAL);
127 return 0;
128 }
129#endif
130 }
131
132 ref -= *ip++;
133
134 if (op + len + 2 > out_end)
135 {
136 SET_ERRNO (E2BIG);
137 return 0;
138 }
139
140 if (ref < (u8 *)out_data)
141 {
142 SET_ERRNO (EINVAL);
143 return 0;
144 }
145
146#ifdef lzf_movsb
147 len += 2;
148 lzf_movsb (op, ref, len);
149#else
150 switch (len)
151 {
152 default:
153 len += 2;
154
155 if (op >= ref + len)
156 {
157 /* disjunct areas */
158 memcpy (op, ref, len);
159 op += len;
160 }
161 else
162 {
163 /* overlapping, use octte by octte copying */
164 do
165 *op++ = *ref++;
166 while (--len);
167 }
168
169 break;
170
171 case 9: *op++ = *ref++; /* fall-thru */
172 case 8: *op++ = *ref++; /* fall-thru */
173 case 7: *op++ = *ref++; /* fall-thru */
174 case 6: *op++ = *ref++; /* fall-thru */
175 case 5: *op++ = *ref++; /* fall-thru */
176 case 4: *op++ = *ref++; /* fall-thru */
177 case 3: *op++ = *ref++; /* fall-thru */
178 case 2: *op++ = *ref++; /* fall-thru */
179 case 1: *op++ = *ref++; /* fall-thru */
180 case 0: *op++ = *ref++; /* two octets more */
181 *op++ = *ref++; /* fall-thru */
182 }
183#endif
184 }
185 }
186
187 return op - (u8 *)out_data;
188}
189#if defined(__GNUC__) && __GNUC__ >= 5
190#pragma GCC diagnostic pop
191#endif
192