source: roaraudio/libroar/crc.c @ 4585:809eb2858897

Last change on this file since 4585:809eb2858897 was 4585:809eb2858897, checked in by phi, 13 years ago

added CRC24 support

File size: 1.8 KB
Line 
1//crc.c:
2
3/*
4 *      Copyright (C) Philipp 'ph3-der-loewe' Schafft - 2010
5 *
6 *  This file is part of libroar a part of RoarAudio,
7 *  a cross-platform sound system for both, home and professional use.
8 *  See README for details.
9 *
10 *  This file is free software; you can redistribute it and/or modify
11 *  it under the terms of the GNU General Public License version 3
12 *  as published by the Free Software Foundation.
13 *
14 *  libroar is distributed in the hope that it will be useful,
15 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
16 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 *  GNU General Public License for more details.
18 *
19 *  You should have received a copy of the GNU General Public License
20 *  along with this software; see the file COPYING.  If not, write to
21 *  the Free Software Foundation, 51 Franklin Street, Fifth Floor,
22 *  Boston, MA 02110-1301, USA.
23 *
24 *  NOTE for everyone want's to change something and send patches:
25 *  read README and HACKING! There a addition information on
26 *  the license of this document you need to read before you send
27 *  any patches.
28 *
29 *  NOTE for uses of non-GPL (LGPL,...) software using libesd, libartsc
30 *  or libpulse*:
31 *  The libs libroaresd, libroararts and libroarpulse link this lib
32 *  and are therefore GPL. Because of this it may be illigal to use
33 *  them with any software that uses libesd, libartsc or libpulse*.
34 */
35
36#include "libroar.h"
37
38#define CRC24_POLY 0x01864CFBL
39#define CRC24_INIT 0x00B704CEL
40
41uint32_t crc24_add(uint32_t state, const void * data, size_t len) {
42 const unsigned char * p = data;
43 int i;
44
45 if ( data == NULL )
46  return CRC24_INIT;
47
48 for (; len; len--) {
49  state ^= (*p++) << 16;
50  for (i = 0; i < 8; i++) {
51   state <<= 1;
52   if ( state & 0x01000000 )
53    state ^= CRC24_POLY;
54  }
55 }
56
57 return state & 0x00FFFFFFL;
58}
59
60//ll
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