chiark / gitweb /
cleanup: All the whitespace fixes, all at once.
[mLib] / crc32.h
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0875b58f 1/* -*-c-*-
2 *
8656dc50 3 * $Id: crc32.h,v 1.7 2004/04/08 01:36:11 mdw Exp $
0875b58f 4 *
5 * Calculating cyclic redundancy values (non-cryptographic!)
6 *
7 * (c) 1998 Straylight/Edgeware
8 */
9
d4efbcd9 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.
d4efbcd9 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.
d4efbcd9 23 *
c846879c 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
c6e0eaf0 30#ifndef MLIB_CRC32_H
573c5b46 31#define MLIB_CRC32_H
0875b58f 32
33#ifdef __cplusplus
34 extern "C" {
35#endif
36
7b4b46a7 37/*----- Header files ------------------------------------------------------*/
38
c6e0eaf0 39#ifndef MLIB_BITS_H
7b4b46a7 40# include "bits.h"
41#endif
42
0875b58f 43/*----- External values ---------------------------------------------------*/
44
7b4b46a7 45extern uint32 crc32_table[256];
0875b58f 46
47/*----- Macros ------------------------------------------------------------*/
48
49/* --- @CRC32@ --- *
50 *
7b4b46a7 51 * Arguments: @uint32 result@ = where to put the result
52 * @uint32 crc@ = carryover from previous call, or zero
0875b58f 53 * @void *buf@ = pointer to buffer to check
54 * @size_t sz@ = size of the buffer
55 *
56 * Use: A restartable CRC calculator wrapped up in a macro.
57 */
58
59#define CRC32(result, crc, buf, sz) do { \
7b4b46a7 60 const octet *_p = (const octet *)(buf); \
61 const octet *_l = _p + (sz); \
62 uint32 _crc = U32(~(crc)); \
0875b58f 63 \
64 while (_p < _l) \
7b4b46a7 65 _crc = (_crc >> 8) ^ crc32_table[U8(*_p++ ^ _crc)]; \
66 (result) = U32(~_crc); \
0875b58f 67} while (0)
68
69/*----- Functions provided ------------------------------------------------*/
70
71/* --- @crc32@ --- *
72 *
7b4b46a7 73 * Arguments: @uint32 crc@ = carryover from previous call, or zero
0875b58f 74 * @const void *buf@ = pointer to buffer to check
75 * @size_t sz@ = size of the buffer
76 *
77 * Returns: The CRC updated by the new buffer.
78 *
79 * Use: A restartable CRC calculator. This is just a function
80 * wrapper for the macro version.
81 */
82
7b4b46a7 83extern uint32 crc32(uint32 /*crc*/, const void */*buf*/, size_t /*sz*/);
0875b58f 84
85/*----- That's all, folks -------------------------------------------------*/
86
87#ifdef __cplusplus
88 }
89#endif
90
91#endif