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Diffstat (limited to 'pathologist/refs/src/bug_crypto_crc.c')
-rw-r--r-- | pathologist/refs/src/bug_crypto_crc.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/pathologist/refs/src/bug_crypto_crc.c b/pathologist/refs/src/bug_crypto_crc.c new file mode 100644 index 0000000..f252785 --- /dev/null +++ b/pathologist/refs/src/bug_crypto_crc.c | |||
@@ -0,0 +1,121 @@ | |||
1 | /* | ||
2 | This file is part of GNUnet. | ||
3 | (C) 2001, 2002, 2003, 2004, 2006 Christian Grothoff (and other contributing authors) | ||
4 | |||
5 | GNUnet is free software; you can redistribute it and/or modify | ||
6 | it under the terms of the GNU General Public License as published | ||
7 | by the Free Software Foundation; either version 2, or (at your | ||
8 | option) any later version. | ||
9 | |||
10 | GNUnet is distributed in the hope that it will be useful, but | ||
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
13 | General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU General Public License | ||
16 | along with GNUnet; see the file COPYING. If not, write to the | ||
17 | Free Software Foundation, Inc., 59 Temple Place - Suite 330, | ||
18 | Boston, MA 02111-1307, USA. | ||
19 | |||
20 | For the actual CRC code: | ||
21 | Copyright abandoned; this code is in the public domain. | ||
22 | Provided to GNUnet by peter@horizon.com | ||
23 | */ | ||
24 | |||
25 | /** | ||
26 | * @file monkey/bug_crypto_crc.c | ||
27 | * @brief implementation of CRC32 (this code has been copied from GNUnet util source directory, and modified to be Seaspider friendly) | ||
28 | * @author Christian Grothoff, Safey A.Halim | ||
29 | */ | ||
30 | |||
31 | #include <assert.h> | ||
32 | #include <stdlib.h> | ||
33 | #include <stdio.h> | ||
34 | #include <stdint.h> | ||
35 | |||
36 | #define Z_NULL 0 | ||
37 | |||
38 | |||
39 | #define POLYNOMIAL (unsigned long)0xedb88320 | ||
40 | static unsigned long crc_table[256]; | ||
41 | |||
42 | /* | ||
43 | * This routine writes each crc_table entry exactly once, | ||
44 | * with the ccorrect final value. Thus, it is safe to call | ||
45 | * even on a table that someone else is using concurrently. | ||
46 | */ | ||
47 | static void | ||
48 | crc_init () | ||
49 | { | ||
50 | static int once; | ||
51 | unsigned int i, j; | ||
52 | unsigned long h = 1; | ||
53 | |||
54 | if (once) | ||
55 | return; | ||
56 | once = 1; | ||
57 | crc_table[0] = 0; | ||
58 | for (i = 128; i; i >>= 1) | ||
59 | { | ||
60 | h = (h >> 1) ^ ((h & 1) ? POLYNOMIAL : 0); | ||
61 | /* h is now crc_table[i] */ | ||
62 | for (j = 0; j < 256; j += 2 * i) | ||
63 | crc_table[i + j] = crc_table[j] ^ h; | ||
64 | } | ||
65 | } | ||
66 | |||
67 | /* | ||
68 | * This computes the standard preset and inverted CRC, as used | ||
69 | * by most networking standards. Start by passing in an initial | ||
70 | * chaining value of 0, and then pass in the return value from the | ||
71 | * previous crc32() call. The final return value is the CRC. | ||
72 | * Note that this is a little-endian CRC, which is best used with | ||
73 | * data transmitted lsbit-first, and it should, itself, be appended | ||
74 | * to data in little-endian byte and bit order to preserve the | ||
75 | * property of detecting all burst errors of length 32 bits or less. | ||
76 | */ | ||
77 | static unsigned long | ||
78 | crc_go (unsigned long crc, const char *buf, size_t len) | ||
79 | { | ||
80 | crc_init (); | ||
81 | assert (crc_table[255] != 0); | ||
82 | crc ^= 0xffffffff; | ||
83 | while (len--) | ||
84 | crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff]; | ||
85 | return crc ^ 0xffffffff; | ||
86 | } | ||
87 | |||
88 | |||
89 | /** | ||
90 | * Compute the CRC32 checksum for the first len bytes of the buffer. | ||
91 | * | ||
92 | * @param buf the data over which we're taking the CRC | ||
93 | * @param len the length of the buffer | ||
94 | * @return the resulting CRC32 checksum | ||
95 | */ | ||
96 | int32_t | ||
97 | crc32_n (const void *buf, size_t len) | ||
98 | { | ||
99 | unsigned long crc; | ||
100 | crc = crc_go (0L, Z_NULL, 0); | ||
101 | crc = crc_go (crc, (char *) buf, len); | ||
102 | return crc; | ||
103 | } | ||
104 | |||
105 | |||
106 | int main () | ||
107 | { | ||
108 | char buf[1024]; | ||
109 | int i; | ||
110 | for (i = 0; i < 1024; i++) | ||
111 | { | ||
112 | buf[i] = (char) i; | ||
113 | } | ||
114 | for (i = 0; i < 1024; i++) | ||
115 | { | ||
116 | printf("%d\n", crc32_n (&buf[i], 1024 - i)); | ||
117 | } | ||
118 | return 0; | ||
119 | } | ||
120 | |||
121 | /* end of bug_crypto_crc.c */ | ||