summaryrefslogtreecommitdiff
path: root/games/adventure/crc.c
blob: 34020907e69a7d8e9402b448ac5ffa748f8829cb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/*	$NetBSD: crc.c,v 1.2 1995/03/21 12:04:59 cgd Exp $	*/

/*-
 * Copyright (c) 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * James W. Williams of the University of Maryland.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 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 OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
#if 0
static char sccsid[] = "@(#)crc.c	8.1 (Berkeley) 5/31/93";
static char ORIGINAL_sccsid[] = "@(#)crc.c	5.2 (Berkeley) 4/4/91";
#else
static char rcsid[] = "$NetBSD: crc.c,v 1.2 1995/03/21 12:04:59 cgd Exp $";
#endif
#endif /* not lint */

typedef	unsigned long	u_long;

u_long crctab[] = {
	0x7fffffff,
	0x77073096,  0xee0e612c,  0x990951ba,  0x076dc419,  0x706af48f,
	0xe963a535,  0x9e6495a3,  0x0edb8832,  0x79dcb8a4,  0xe0d5e91e,
	0x97d2d988,  0x09b64c2b,  0x7eb17cbd,  0xe7b82d07,  0x90bf1d91,
	0x1db71064,  0x6ab020f2,  0xf3b97148,  0x84be41de,  0x1adad47d,
	0x6ddde4eb,  0xf4d4b551,  0x83d385c7,  0x136c9856,  0x646ba8c0,
	0xfd62f97a,  0x8a65c9ec,  0x14015c4f,  0x63066cd9,  0xfa0f3d63,
	0x8d080df5,  0x3b6e20c8,  0x4c69105e,  0xd56041e4,  0xa2677172,
	0x3c03e4d1,  0x4b04d447,  0xd20d85fd,  0xa50ab56b,  0x35b5a8fa,
	0x42b2986c,  0xdbbbc9d6,  0xacbcf940,  0x32d86ce3,  0x45df5c75,
	0xdcd60dcf,  0xabd13d59,  0x26d930ac,  0x51de003a,  0xc8d75180,
	0xbfd06116,  0x21b4f4b5,  0x56b3c423,  0xcfba9599,  0xb8bda50f,
	0x2802b89e,  0x5f058808,  0xc60cd9b2,  0xb10be924,  0x2f6f7c87,
	0x58684c11,  0xc1611dab,  0xb6662d3d,  0x76dc4190,  0x01db7106,
	0x98d220bc,  0xefd5102a,  0x71b18589,  0x06b6b51f,  0x9fbfe4a5,
	0xe8b8d433,  0x7807c9a2,  0x0f00f934,  0x9609a88e,  0xe10e9818,
	0x7f6a0dbb,  0x086d3d2d,  0x91646c97,  0xe6635c01,  0x6b6b51f4,
	0x1c6c6162,  0x856530d8,  0xf262004e,  0x6c0695ed,  0x1b01a57b,
	0x8208f4c1,  0xf50fc457,  0x65b0d9c6,  0x12b7e950,  0x8bbeb8ea,
	0xfcb9887c,  0x62dd1ddf,  0x15da2d49,  0x8cd37cf3,  0xfbd44c65,
	0x4db26158,  0x3ab551ce,  0xa3bc0074,  0xd4bb30e2,  0x4adfa541,
	0x3dd895d7,  0xa4d1c46d,  0xd3d6f4fb,  0x4369e96a,  0x346ed9fc,
	0xad678846,  0xda60b8d0,  0x44042d73,  0x33031de5,  0xaa0a4c5f,
	0xdd0d7cc9,  0x5005713c,  0x270241aa,  0xbe0b1010,  0xc90c2086,
	0x5768b525,  0x206f85b3,  0xb966d409,  0xce61e49f,  0x5edef90e,
	0x29d9c998,  0xb0d09822,  0xc7d7a8b4,  0x59b33d17,  0x2eb40d81,
	0xb7bd5c3b,  0xc0ba6cad,  0xedb88320,  0x9abfb3b6,  0x03b6e20c,
	0x74b1d29a,  0xead54739,  0x9dd277af,  0x04db2615,  0x73dc1683,
	0xe3630b12,  0x94643b84,  0x0d6d6a3e,  0x7a6a5aa8,  0xe40ecf0b,
	0x9309ff9d,  0x0a00ae27,  0x7d079eb1,  0xf00f9344,  0x8708a3d2,
	0x1e01f268,  0x6906c2fe,  0xf762575d,  0x806567cb,  0x196c3671,
	0x6e6b06e7,  0xfed41b76,  0x89d32be0,  0x10da7a5a,  0x67dd4acc,
	0xf9b9df6f,  0x8ebeeff9,  0x17b7be43,  0x60b08ed5,  0xd6d6a3e8,
	0xa1d1937e,  0x38d8c2c4,  0x4fdff252,  0xd1bb67f1,  0xa6bc5767,
	0x3fb506dd,  0x48b2364b,  0xd80d2bda,  0xaf0a1b4c,  0x36034af6,
	0x41047a60,  0xdf60efc3,  0xa867df55,  0x316e8eef,  0x4669be79,
	0xcb61b38c,  0xbc66831a,  0x256fd2a0,  0x5268e236,  0xcc0c7795,
	0xbb0b4703,  0x220216b9,  0x5505262f,  0xc5ba3bbe,  0xb2bd0b28,
	0x2bb45a92,  0x5cb36a04,  0xc2d7ffa7,  0xb5d0cf31,  0x2cd99e8b,
	0x5bdeae1d,  0x9b64c2b0,  0xec63f226,  0x756aa39c,  0x026d930a,
	0x9c0906a9,  0xeb0e363f,  0x72076785,  0x05005713,  0x95bf4a82,
	0xe2b87a14,  0x7bb12bae,  0x0cb61b38,  0x92d28e9b,  0xe5d5be0d,
	0x7cdcefb7,  0x0bdbdf21,  0x86d3d2d4,  0xf1d4e242,  0x68ddb3f8,
	0x1fda836e,  0x81be16cd,  0xf6b9265b,  0x6fb077e1,  0x18b74777,
	0x88085ae6,  0xff0f6a70,  0x66063bca,  0x11010b5c,  0x8f659eff,
	0xf862ae69,  0x616bffd3,  0x166ccf45,  0xa00ae278,  0xd70dd2ee,
	0x4e048354,  0x3903b3c2,  0xa7672661,  0xd06016f7,  0x4969474d,
	0x3e6e77db,  0xaed16a4a,  0xd9d65adc,  0x40df0b66,  0x37d83bf0,
	0xa9bcae53,  0xdebb9ec5,  0x47b2cf7f,  0x30b5ffe9,  0xbdbdf21c,
	0xcabac28a,  0x53b39330,  0x24b4a3a6,  0xbad03605,  0xcdd70693,
	0x54de5729,  0x23d967bf,  0xb3667a2e,  0xc4614ab8,  0x5d681b02,
	0x2a6f2b94,  0xb40bbe37,  0xc30c8ea1,  0x5a05df1b,  0x2d02ef8d
};

/*
 * crc --
 *      Compute a POSIX.2 checksum.  This routine modified by Jim Gillogly
 *      to work on sequential data rather than on a file.  Initial call to
 *      crc_start initializes the sum, and subsequent calls to crc update
 *      it.
 */

u_long crcval;
int step;

crc_start()
{
	crcval = step = 0;
}

u_long crc(ptr, nr) /* Process nr bytes at a time; ptr points to them */
char *ptr;
int nr;
{
	register int i;
	register char *p;

	while (nr > 0)
		for (p = ptr; nr--; ++p)
		{
			if (!(i = crcval >> 24 ^ *p))
			{
				i = step++;
				if (step >= sizeof(crctab)/sizeof(crctab[0]))
					step = 0;
			}
			crcval = (crcval << 8) ^ crctab[i];
		}
	return crcval & 0xffffffff;		  /* Mask to 32 bits. */
}