liblzf/lzf_d.c

/*
 * Copyright (c) 2000-2003 Marc Alexander Lehmann <pcg@goof.com>
 * 
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 * 
 *   3.  The name of the author may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License version 2 (the "GPL"), in which case the
 * provisions of the GPL are applicable instead of the above. If you wish to
 * allow the use of your version of this file only under the terms of the
 * GPL and not to allow others to use your version of this file under the
 * BSD license, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the GPL. If
 * you do not delete the provisions above, a recipient may use your version
 * of this file under either the BSD or the GPL.
 */

#include "lzfP.h"

#if AVOID_ERRNO
# define SET_ERRNO(n)
#else
# include <errno.h>
# define SET_ERRNO(n) errno = (n)
#endif

unsigned int 
lzf_decompress (const void *const in_data,  unsigned int in_len,
                void             *out_data, unsigned int out_len)
{
  u8 const *ip = (const u8 *)in_data;
  u8       *op = (u8 *)out_data;
  u8 const *const in_end  = ip + in_len;
  u8       *const out_end = op + out_len;

  do
    {
      unsigned int ctrl = *ip++;

      if (ctrl < (1 << 5)) /* literal run */
        {
          ctrl++;

          if (op + ctrl > out_end)
            {
              SET_ERRNO (E2BIG);
              return 0;
            }

#if USE_MEMCPY
          memcpy (op, ip, ctrl);
          op += ctrl;
          ip += ctrl;
#else
          do
            *op++ = *ip++;
          while (--ctrl);
#endif
        }
      else /* back reference */
        {
          unsigned int len = ctrl >> 5;

          u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;

          if (len == 7)
            len += *ip++;
          
          ref -= *ip++;

          if (op + len + 2 > out_end)
            {
              SET_ERRNO (E2BIG);
              return 0;
            }

          if (ref < (u8 *)out_data)
            {
              SET_ERRNO (EINVAL);
              return 0;
            }

          *op++ = *ref++;
          *op++ = *ref++;

          do
            *op++ = *ref++;
          while (--len);
        }
    }
  while (op < out_end && ip < in_end);

  return op - (u8 *)out_data;
}

Revision:	1.4
Committed:	Tue Apr 20 18:12:00 2004 UTC (20 years, 1 month ago) by pcg
Content type:	text/plain
Branch:	MAIN
Changes since 1.3:	+10 -0 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2	pcg	1.3	* Copyright (c) 2000-2003 Marc Alexander Lehmann <pcg@goof.com>
3	root	1.1	*
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			* 3. The name of the author may not be used to endorse or promote products
15			* derived from this software without specific prior written permission.
16			*
17			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19			* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20			* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26			* OF THE POSSIBILITY OF SUCH DAMAGE.
27	pcg	1.4	*
28			* Alternatively, the contents of this file may be used under the terms of
29			* the GNU General Public License version 2 (the "GPL"), in which case the
30			* provisions of the GPL are applicable instead of the above. If you wish to
31			* allow the use of your version of this file only under the terms of the
32			* GPL and not to allow others to use your version of this file under the
33			* BSD license, indicate your decision by deleting the provisions above and
34			* replace them with the notice and other provisions required by the GPL. If
35			* you do not delete the provisions above, a recipient may use your version
36			* of this file under either the BSD or the GPL.
37	root	1.1	*/
38
39	pcg	1.3	#include "lzfP.h"
40	root	1.1
41	pcg	1.3	#if AVOID_ERRNO
42			# define SET_ERRNO(n)
43			#else
44			# include <errno.h>
45			# define SET_ERRNO(n) errno = (n)
46			#endif
47	root	1.1
48			unsigned int
49			lzf_decompress (const void *const in_data, unsigned int in_len,
50			void *out_data, unsigned int out_len)
51			{
52	pcg	1.3	u8 const ip = (const u8 )in_data;
53			u8 op = (u8 )out_data;
54	root	1.1	u8 const *const in_end = ip + in_len;
55			u8 *const out_end = op + out_len;
56
57			do
58			{
59			unsigned int ctrl = *ip++;
60
61			if (ctrl < (1 << 5)) /* literal run */
62			{
63			ctrl++;
64
65			if (op + ctrl > out_end)
66			{
67	pcg	1.3	SET_ERRNO (E2BIG);
68	root	1.1	return 0;
69			}
70
71			#if USE_MEMCPY
72			memcpy (op, ip, ctrl);
73			op += ctrl;
74			ip += ctrl;
75			#else
76			do
77			op++ = ip++;
78			while (--ctrl);
79			#endif
80			}
81			else /* back reference */
82			{
83			unsigned int len = ctrl >> 5;
84
85			u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;
86
87			if (len == 7)
88			len += *ip++;
89
90			ref -= *ip++;
91
92			if (op + len + 2 > out_end)
93			{
94	pcg	1.3	SET_ERRNO (E2BIG);
95	root	1.1	return 0;
96			}
97
98			if (ref < (u8 *)out_data)
99			{
100	pcg	1.3	SET_ERRNO (EINVAL);
101	root	1.1	return 0;
102			}
103
104			op++ = ref++;
105			op++ = ref++;
106
107			do
108			op++ = ref++;
109			while (--len);
110			}
111			}
112			while (op < out_end && ip < in_end);
113
114			return op - (u8 *)out_data;
115			}
116