3 * $Id: crc32.h,v 1.7 2004/04/08 01:36:11 mdw Exp $
5 * Calculating cyclic redundancy values (non-cryptographic!)
7 * (c) 1998 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
14 * mLib is free software; you can redistribute it and/or modify
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.
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
22 * GNU Library General Public License for more details.
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
37 /*----- Header files ------------------------------------------------------*/
43 /*----- External values ---------------------------------------------------*/
45 extern uint32 crc32_table[256];
47 /*----- Macros ------------------------------------------------------------*/
51 * Arguments: @uint32 result@ = where to put the result
52 * @uint32 crc@ = carryover from previous call, or zero
53 * @void *buf@ = pointer to buffer to check
54 * @size_t sz@ = size of the buffer
56 * Use: A restartable CRC calculator wrapped up in a macro.
59 #define CRC32(result, crc, buf, sz) do { \
60 const octet *_p = (const octet *)(buf); \
61 const octet *_l = _p + (sz); \
62 uint32 _crc = U32(~(crc)); \
65 _crc = (_crc >> 8) ^ crc32_table[U8(*_p++ ^ _crc)]; \
66 (result) = U32(~_crc); \
69 /*----- Functions provided ------------------------------------------------*/
73 * Arguments: @uint32 crc@ = carryover from previous call, or zero
74 * @const void *buf@ = pointer to buffer to check
75 * @size_t sz@ = size of the buffer
77 * Returns: The CRC updated by the new buffer.
79 * Use: A restartable CRC calculator. This is just a function
80 * wrapper for the macro version.
83 extern uint32 crc32(uint32 /*crc*/, const void */*buf*/, size_t /*sz*/);
85 /*----- That's all, folks -------------------------------------------------*/