1/*
2 * Copyright (c) 2000-2010 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
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
55unsigned int
56lzf_decompress (const void *const in_data,  unsigned int in_len,
57                void             *out_data, unsigned int out_len)
58{
59  u8 const *ip = (const u8 *)in_data;
60  u8       *op = (u8 *)out_data;
61  u8 const *const in_end  = ip + in_len;
62  u8       *const out_end = op + out_len;
63
64  do
65    {
66      unsigned int ctrl = *ip++;
67
68      if (ctrl < (1 << 5)) /* literal run */
69        {
70          ctrl++;
71
72          if (op + ctrl > out_end)
73            {
74              SET_ERRNO (E2BIG);
75              return 0;
76            }
77
78#if CHECK_INPUT
79          if (ip + ctrl > in_end)
80            {
81              SET_ERRNO (EINVAL);
82              return 0;
83            }
84#endif
85
86#ifdef lzf_movsb
87          lzf_movsb (op, ip, ctrl);
88#else
89          switch (ctrl)
90            {
91              case 32: *op++ = *ip++; case 31: *op++ = *ip++; case 30: *op++ = *ip++; case 29: *op++ = *ip++;
92              case 28: *op++ = *ip++; case 27: *op++ = *ip++; case 26: *op++ = *ip++; case 25: *op++ = *ip++;
93              case 24: *op++ = *ip++; case 23: *op++ = *ip++; case 22: *op++ = *ip++; case 21: *op++ = *ip++;
94              case 20: *op++ = *ip++; case 19: *op++ = *ip++; case 18: *op++ = *ip++; case 17: *op++ = *ip++;
95              case 16: *op++ = *ip++; case 15: *op++ = *ip++; case 14: *op++ = *ip++; case 13: *op++ = *ip++;
96              case 12: *op++ = *ip++; case 11: *op++ = *ip++; case 10: *op++ = *ip++; case  9: *op++ = *ip++;
97              case  8: *op++ = *ip++; case  7: *op++ = *ip++; case  6: *op++ = *ip++; case  5: *op++ = *ip++;
98              case  4: *op++ = *ip++; case  3: *op++ = *ip++; case  2: *op++ = *ip++; case  1: *op++ = *ip++;
99            }
100#endif
101        }
102      else /* back reference */
103        {
104          unsigned int len = ctrl >> 5;
105
106          u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;
107
108#if CHECK_INPUT
109          if (ip >= in_end)
110            {
111              SET_ERRNO (EINVAL);
112              return 0;
113            }
114#endif
115          if (len == 7)
116            {
117              len += *ip++;
118#if CHECK_INPUT
119              if (ip >= in_end)
120                {
121                  SET_ERRNO (EINVAL);
122                  return 0;
123                }
124#endif
125            }
126
127          ref -= *ip++;
128
129          if (op + len + 2 > out_end)
130            {
131              SET_ERRNO (E2BIG);
132              return 0;
133            }
134
135          if (ref < (u8 *)out_data)
136            {
137              SET_ERRNO (EINVAL);
138              return 0;
139            }
140
141#ifdef lzf_movsb
142          len += 2;
143          lzf_movsb (op, ref, len);
144#else
145          switch (len)
146            {
147              default:
148                len += 2;
149
150                if (op >= ref + len)
151                  {
152                    /* disjunct areas */
153                    memcpy (op, ref, len);
154                    op += len;
155                  }
156                else
157                  {
158                    /* overlapping, use octte by octte copying */
159                    do
160                      *op++ = *ref++;
161                    while (--len);
162                  }
163
164                break;
165
166              case 9: *op++ = *ref++;
167              case 8: *op++ = *ref++;
168              case 7: *op++ = *ref++;
169              case 6: *op++ = *ref++;
170              case 5: *op++ = *ref++;
171              case 4: *op++ = *ref++;
172              case 3: *op++ = *ref++;
173              case 2: *op++ = *ref++;
174              case 1: *op++ = *ref++;
175              case 0: *op++ = *ref++; /* two octets more */
176                      *op++ = *ref++;
177            }
178#endif
179        }
180    }
181  while (ip < in_end);
182
183  return op - (u8 *)out_data;
184}
185
186