3 * $Id: crc32.h,v 1.4 1999/06/01 09:47:22 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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.4 1999/06/01 09:47:22 mdw
34 * Make the return type of `crc32' a `uint32' now that we have `bits.h'.
36 * Revision 1.3 1999/05/06 19:51:35 mdw
37 * Reformatted the LGPL notice a little bit.
39 * Revision 1.2 1999/05/05 18:50:31 mdw
40 * Change licensing conditions to LGPL.
42 * Revision 1.1.1.1 1998/06/17 23:44:42 mdw
43 * Initial version of mLib
54 /*----- Header files ------------------------------------------------------*/
60 /*----- External values ---------------------------------------------------*/
62 extern uint32 crc32_table
[256];
64 /*----- Macros ------------------------------------------------------------*/
68 * Arguments: @uint32 result@ = where to put the result
69 * @uint32 crc@ = carryover from previous call, or zero
70 * @void *buf@ = pointer to buffer to check
71 * @size_t sz@ = size of the buffer
73 * Use: A restartable CRC calculator wrapped up in a macro.
76 #define CRC32(result, crc, buf, sz) do { \
77 const octet *_p = (const octet *)(buf); \
78 const octet *_l = _p + (sz); \
79 uint32 _crc = U32(~(crc)); \
82 _crc = (_crc >> 8) ^ crc32_table[U8(*_p++ ^ _crc)]; \
83 (result) = U32(~_crc); \
86 /*----- Functions provided ------------------------------------------------*/
90 * Arguments: @uint32 crc@ = carryover from previous call, or zero
91 * @const void *buf@ = pointer to buffer to check
92 * @size_t sz@ = size of the buffer
94 * Returns: The CRC updated by the new buffer.
96 * Use: A restartable CRC calculator. This is just a function
97 * wrapper for the macro version.
100 extern uint32
crc32(uint32
/*crc*/, const void */
*buf*/
, size_t /*sz*/);
102 /*----- That's all, folks -------------------------------------------------*/