0875b58f |
1 | /* -*-c-*- |
2 | * |
c6e0eaf0 |
3 | * $Id: crc32.h,v 1.5 1999/12/10 23:42:04 mdw Exp $ |
0875b58f |
4 | * |
5 | * Calculating cyclic redundancy values (non-cryptographic!) |
6 | * |
7 | * (c) 1998 Straylight/Edgeware |
8 | */ |
9 | |
c846879c |
10 | /*----- Licensing notice --------------------------------------------------* |
0875b58f |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
c846879c |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
0875b58f |
19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
c846879c |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
0bd98442 |
25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
0875b58f |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: crc32.h,v $ |
c6e0eaf0 |
33 | * Revision 1.5 1999/12/10 23:42:04 mdw |
34 | * Change header file guard names. |
35 | * |
7b4b46a7 |
36 | * Revision 1.4 1999/06/01 09:47:22 mdw |
37 | * Make the return type of `crc32' a `uint32' now that we have `bits.h'. |
38 | * |
0bd98442 |
39 | * Revision 1.3 1999/05/06 19:51:35 mdw |
40 | * Reformatted the LGPL notice a little bit. |
41 | * |
c846879c |
42 | * Revision 1.2 1999/05/05 18:50:31 mdw |
43 | * Change licensing conditions to LGPL. |
44 | * |
45 | * Revision 1.1.1.1 1998/06/17 23:44:42 mdw |
46 | * Initial version of mLib |
0875b58f |
47 | * |
48 | */ |
49 | |
c6e0eaf0 |
50 | #ifndef MLIB_CRC32_H |
0875b58f |
51 | #define CRC32_h |
52 | |
53 | #ifdef __cplusplus |
54 | extern "C" { |
55 | #endif |
56 | |
7b4b46a7 |
57 | /*----- Header files ------------------------------------------------------*/ |
58 | |
c6e0eaf0 |
59 | #ifndef MLIB_BITS_H |
7b4b46a7 |
60 | # include "bits.h" |
61 | #endif |
62 | |
0875b58f |
63 | /*----- External values ---------------------------------------------------*/ |
64 | |
7b4b46a7 |
65 | extern uint32 crc32_table[256]; |
0875b58f |
66 | |
67 | /*----- Macros ------------------------------------------------------------*/ |
68 | |
69 | /* --- @CRC32@ --- * |
70 | * |
7b4b46a7 |
71 | * Arguments: @uint32 result@ = where to put the result |
72 | * @uint32 crc@ = carryover from previous call, or zero |
0875b58f |
73 | * @void *buf@ = pointer to buffer to check |
74 | * @size_t sz@ = size of the buffer |
75 | * |
76 | * Use: A restartable CRC calculator wrapped up in a macro. |
77 | */ |
78 | |
79 | #define CRC32(result, crc, buf, sz) do { \ |
7b4b46a7 |
80 | const octet *_p = (const octet *)(buf); \ |
81 | const octet *_l = _p + (sz); \ |
82 | uint32 _crc = U32(~(crc)); \ |
0875b58f |
83 | \ |
84 | while (_p < _l) \ |
7b4b46a7 |
85 | _crc = (_crc >> 8) ^ crc32_table[U8(*_p++ ^ _crc)]; \ |
86 | (result) = U32(~_crc); \ |
0875b58f |
87 | } while (0) |
88 | |
89 | /*----- Functions provided ------------------------------------------------*/ |
90 | |
91 | /* --- @crc32@ --- * |
92 | * |
7b4b46a7 |
93 | * Arguments: @uint32 crc@ = carryover from previous call, or zero |
0875b58f |
94 | * @const void *buf@ = pointer to buffer to check |
95 | * @size_t sz@ = size of the buffer |
96 | * |
97 | * Returns: The CRC updated by the new buffer. |
98 | * |
99 | * Use: A restartable CRC calculator. This is just a function |
100 | * wrapper for the macro version. |
101 | */ |
102 | |
7b4b46a7 |
103 | extern uint32 crc32(uint32 /*crc*/, const void */*buf*/, size_t /*sz*/); |
0875b58f |
104 | |
105 | /*----- That's all, folks -------------------------------------------------*/ |
106 | |
107 | #ifdef __cplusplus |
108 | } |
109 | #endif |
110 | |
111 | #endif |