/[dynamips]/upstream/dynamips-0.2.7-RC1/crc.c
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Contents of /upstream/dynamips-0.2.7-RC1/crc.c

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Revision 1 - (show annotations)
Sat Oct 6 16:01:44 2007 UTC (12 years, 2 months ago) by dpavlin
Original Path: upstream/dynamips-0.2.5/crc.c
File MIME type: text/plain
File size: 1752 byte(s)
import 0.2.5 from upstream

1 /*
2 * Cisco 7200 (Predator) simulation platform.
3 * Copyright (c) 2006 Christophe Fillot (cf@utc.fr)
4 *
5 * CRC functions.
6 */
7
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <unistd.h>
11 #include <string.h>
12 #include <sys/types.h>
13 #include <sys/stat.h>
14 #include <sys/mman.h>
15 #include <signal.h>
16 #include <fcntl.h>
17 #include <assert.h>
18
19 #include "utils.h"
20 #include "crc.h"
21
22 #define CRC12_POLY 0x0f01
23 #define CRC16_POLY 0xa001
24 #define CRC32_POLY 0xedb88320L
25
26 /* CRC tables */
27 m_uint16_t crc12_array[256],crc16_array[256];
28 m_uint32_t crc32_array[256];
29
30 /* Initialize CRC-12 algorithm */
31 static void crc12_init(void)
32 {
33 m_uint16_t crc,c;
34 int i,j;
35
36 for(i=0;i<256;i++) {
37 crc = 0;
38 c = (m_uint16_t)i;
39
40 for(j=0;j<8;j++) {
41 if ((crc ^ c) & 0x0001)
42 crc = (crc >> 1) ^ CRC12_POLY;
43 else
44 crc = crc >> 1;
45
46 c = c >> 1;
47 }
48
49 crc12_array[i] = crc;
50 }
51 }
52
53 /* Initialize CRC-16 algorithm */
54 static void crc16_init(void)
55 {
56 m_uint16_t crc,c;
57 int i,j;
58
59 for(i=0;i<256;i++) {
60 crc = 0;
61 c = (m_uint16_t)i;
62
63 for(j=0;j<8;j++) {
64 if ((crc ^ c) & 0x0001)
65 crc = (crc >> 1) ^ CRC16_POLY;
66 else
67 crc = crc >> 1;
68
69 c = c >> 1;
70 }
71
72 crc16_array[i] = crc;
73 }
74 }
75
76 /* Initialize CRC-32 algorithm */
77 static void crc32_init(void)
78 {
79 unsigned long c;
80 int n, k;
81
82 for (n=0;n<256;n++) {
83 c = (unsigned long) n;
84 for (k = 0; k < 8; k++) {
85 if (c & 1)
86 c = CRC32_POLY ^ (c >> 1);
87 else
88 c = c >> 1;
89 }
90 crc32_array[n] = c;
91 }
92 }
93
94 /* Initialize CRC algorithms */
95 void crc_init(void)
96 {
97 crc12_init();
98 crc16_init();
99 crc32_init();
100 }

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