liblzf/lzf_d.c

/*
 * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de>
 * 
 * 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.
 * 
 * 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 ("GPL") version 2 or any later version,
 * 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"

#include <string.h> /* for memcpy/memset */

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

#if USE_REP_MOVSB /* small win on amd, big loss on intel */
#if (__i386 || __amd64) && __GNUC__ >= 3
# define lzf_movsb(dst, src, len)                \
   asm ("rep movsb"                              \
        : "=D" (dst), "=S" (src), "=c" (len)     \
        :  "0" (dst),  "1" (src),  "2" (len));
#endif
#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 CHECK_INPUT
          if (ip + ctrl > in_end)
            {
              SET_ERRNO (EINVAL);
              return 0;
            }
#endif

#ifdef lzf_movsb
          lzf_movsb (op, ip, ctrl);
#else
          switch (ctrl)
            {
              case 32: *op++ = *ip++; case 31: *op++ = *ip++; case 30: *op++ = *ip++; case 29: *op++ = *ip++;
              case 28: *op++ = *ip++; case 27: *op++ = *ip++; case 26: *op++ = *ip++; case 25: *op++ = *ip++;
              case 24: *op++ = *ip++; case 23: *op++ = *ip++; case 22: *op++ = *ip++; case 21: *op++ = *ip++;
              case 20: *op++ = *ip++; case 19: *op++ = *ip++; case 18: *op++ = *ip++; case 17: *op++ = *ip++;
              case 16: *op++ = *ip++; case 15: *op++ = *ip++; case 14: *op++ = *ip++; case 13: *op++ = *ip++;
              case 12: *op++ = *ip++; case 11: *op++ = *ip++; case 10: *op++ = *ip++; case  9: *op++ = *ip++;
              case  8: *op++ = *ip++; case  7: *op++ = *ip++; case  6: *op++ = *ip++; case  5: *op++ = *ip++;
              case  4: *op++ = *ip++; case  3: *op++ = *ip++; case  2: *op++ = *ip++; case  1: *op++ = *ip++;
            }
#endif
        }
      else /* back reference */
        {
          unsigned int len = ctrl >> 5;

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

#if CHECK_INPUT
          if (ip >= in_end)
            {
              SET_ERRNO (EINVAL);
              return 0;
            }
#endif
          if (len == 7)
            {
              len += *ip++;
#if CHECK_INPUT
              if (ip >= in_end)
                {
                  SET_ERRNO (EINVAL);
                  return 0;
                }
#endif
            }

          ref -= *ip++;

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

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

#ifdef lzf_movsb
          len += 2;
          lzf_movsb (op, ref, len);
#else
          switch (len)
            {
              default:
                len += 2;

                if (op >= ref + len)
                  {
                    /* disjunct areas */
                    memcpy (op, ref, len);
                    op += len;
                  }
                else
                  {
                    /* overlapping, use octte by octte copying */
                    do
                      *op++ = *ref++;
                    while (--len);
                  }

                break;

              case 9: *op++ = *ref++;
              case 8: *op++ = *ref++;
              case 7: *op++ = *ref++;
              case 6: *op++ = *ref++;
              case 5: *op++ = *ref++;
              case 4: *op++ = *ref++;
              case 3: *op++ = *ref++;
              case 2: *op++ = *ref++;
              case 1: *op++ = *ref++;
              case 0: *op++ = *ref++; /* two octets more */
                      *op++ = *ref++;
            }
#endif
        }
    }
  while (ip < in_end);

  return op - (u8 *)out_data;
}

Revision:	1.10
Committed:	Sun May 30 05:46:56 2010 UTC (13 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.9:	+47 -8 lines
Log Message:	* empty log message *
#	Content
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
39	#include <string.h> /* for memcpy/memset */
40
41	#if AVOID_ERRNO
42	# define SET_ERRNO(n)
43	#else
44	# include <errno.h>
45	# define SET_ERRNO(n) errno = (n)
46	#endif
47
48	#if USE_REP_MOVSB /* small win on amd, big loss on intel */
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	#endif
56
57	unsigned int
58	lzf_decompress (const void *const in_data, unsigned int in_len,
59	void *out_data, unsigned int out_len)
60	{
61	u8 const ip = (const u8 )in_data;
62	u8 op = (u8 )out_data;
63	u8 const *const in_end = ip + in_len;
64	u8 *const out_end = op + out_len;
65
66	do
67	{
68	unsigned int ctrl = *ip++;
69
70	if (ctrl < (1 << 5)) /* literal run */
71	{
72	ctrl++;
73
74	if (op + ctrl > out_end)
75	{
76	SET_ERRNO (E2BIG);
77	return 0;
78	}
79
80	#if CHECK_INPUT
81	if (ip + ctrl > in_end)
82	{
83	SET_ERRNO (EINVAL);
84	return 0;
85	}
86	#endif
87
88	#ifdef lzf_movsb
89	lzf_movsb (op, ip, ctrl);
90	#else
91	switch (ctrl)
92	{
93	case 32: op++ = ip++; case 31: op++ = ip++; case 30: op++ = ip++; case 29: op++ = ip++;
94	case 28: op++ = ip++; case 27: op++ = ip++; case 26: op++ = ip++; case 25: op++ = ip++;
95	case 24: op++ = ip++; case 23: op++ = ip++; case 22: op++ = ip++; case 21: op++ = ip++;
96	case 20: op++ = ip++; case 19: op++ = ip++; case 18: op++ = ip++; case 17: op++ = ip++;
97	case 16: op++ = ip++; case 15: op++ = ip++; case 14: op++ = ip++; case 13: op++ = ip++;
98	case 12: op++ = ip++; case 11: op++ = ip++; case 10: op++ = ip++; case 9: op++ = ip++;
99	case 8: op++ = ip++; case 7: op++ = ip++; case 6: op++ = ip++; case 5: op++ = ip++;
100	case 4: op++ = ip++; case 3: op++ = ip++; case 2: op++ = ip++; case 1: op++ = ip++;
101	}
102	#endif
103	}
104	else /* back reference */
105	{
106	unsigned int len = ctrl >> 5;
107
108	u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;
109
110	#if CHECK_INPUT
111	if (ip >= in_end)
112	{
113	SET_ERRNO (EINVAL);
114	return 0;
115	}
116	#endif
117	if (len == 7)
118	{
119	len += *ip++;
120	#if CHECK_INPUT
121	if (ip >= in_end)
122	{
123	SET_ERRNO (EINVAL);
124	return 0;
125	}
126	#endif
127	}
128
129	ref -= *ip++;
130
131	if (op + len + 2 > out_end)
132	{
133	SET_ERRNO (E2BIG);
134	return 0;
135	}
136
137	if (ref < (u8 *)out_data)
138	{
139	SET_ERRNO (EINVAL);
140	return 0;
141	}
142
143	#ifdef lzf_movsb
144	len += 2;
145	lzf_movsb (op, ref, len);
146	#else
147	switch (len)
148	{
149	default:
150	len += 2;
151
152	if (op >= ref + len)
153	{
154	/* disjunct areas */
155	memcpy (op, ref, len);
156	op += len;
157	}
158	else
159	{
160	/* overlapping, use octte by octte copying */
161	do
162	op++ = ref++;
163	while (--len);
164	}
165
166	break;
167
168	case 9: op++ = ref++;
169	case 8: op++ = ref++;
170	case 7: op++ = ref++;
171	case 6: op++ = ref++;
172	case 5: op++ = ref++;
173	case 4: op++ = ref++;
174	case 3: op++ = ref++;
175	case 2: op++ = ref++;
176	case 1: op++ = ref++;
177	case 0: op++ = ref++; /* two octets more */
178	op++ = ref++;
179	}
180	#endif
181	}
182	}
183	while (ip < in_end);
184
185	return op - (u8 *)out_data;
186	}
187