|
2134
|
1 /*
|
|
|
2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
|
|
|
3 *
|
|
|
4 * This file is part of FFmpeg.
|
|
|
5 *
|
|
|
6 * FFmpeg is free software; you can redistribute it and/or
|
|
|
7 * modify it under the terms of the GNU Lesser General Public
|
|
|
8 * License as published by the Free Software Foundation; either
|
|
|
9 * version 2.1 of the License, or (at your option) any later version.
|
|
|
10 *
|
|
|
11 * FFmpeg is distributed in the hope that it will be useful,
|
|
|
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
14 * Lesser General Public License for more details.
|
|
|
15 *
|
|
|
16 * You should have received a copy of the GNU Lesser General Public
|
|
|
17 * License along with FFmpeg; if not, write to the Free Software
|
|
|
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
|
19 */
|
|
|
20
|
|
|
21 #ifndef AVUTIL_CRC_H
|
|
|
22 #define AVUTIL_CRC_H
|
|
|
23
|
|
|
24 #include <stdint.h>
|
|
|
25 #include <stddef.h>
|
|
|
26 #include "attributes.h"
|
|
|
27
|
|
|
28 typedef uint32_t AVCRC;
|
|
|
29
|
|
|
30 typedef enum {
|
|
|
31 AV_CRC_8_ATM,
|
|
|
32 AV_CRC_16_ANSI,
|
|
|
33 AV_CRC_16_CCITT,
|
|
|
34 AV_CRC_32_IEEE,
|
|
|
35 AV_CRC_32_IEEE_LE, /*< reversed bitorder version of AV_CRC_32_IEEE */
|
|
|
36 AV_CRC_MAX, /*< Not part of public API! Do not use outside libavutil. */
|
|
|
37 }AVCRCId;
|
|
|
38
|
|
|
39 /**
|
|
|
40 * Initialize a CRC table.
|
|
|
41 * @param ctx must be an array of size sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
|
|
|
42 * @param le If 1, the lowest bit represents the coefficient for the highest
|
|
|
43 * exponent of the corresponding polynomial (both for poly and
|
|
|
44 * actual CRC).
|
|
|
45 * If 0, you must swap the CRC parameter and the result of av_crc
|
|
|
46 * if you need the standard representation (can be simplified in
|
|
|
47 * most cases to e.g. bswap16):
|
|
|
48 * av_bswap32(crc << (32-bits))
|
|
|
49 * @param bits number of bits for the CRC
|
|
|
50 * @param poly generator polynomial without the x**bits coefficient, in the
|
|
|
51 * representation as specified by le
|
|
|
52 * @param ctx_size size of ctx in bytes
|
|
|
53 * @return <0 on failure
|
|
|
54 */
|
|
|
55 int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size);
|
|
|
56
|
|
|
57 /**
|
|
|
58 * Get an initialized standard CRC table.
|
|
|
59 * @param crc_id ID of a standard CRC
|
|
|
60 * @return a pointer to the CRC table or NULL on failure
|
|
|
61 */
|
|
|
62 const AVCRC *av_crc_get_table(AVCRCId crc_id);
|
|
|
63
|
|
|
64 /**
|
|
|
65 * Calculate the CRC of a block.
|
|
|
66 * @param crc CRC of previous blocks if any or initial value for CRC
|
|
|
67 * @return CRC updated with the data from the given block
|
|
|
68 *
|
|
|
69 * @see av_crc_init() "le" parameter
|
|
|
70 */
|
|
|
71 uint32_t av_crc(const AVCRC *ctx, uint32_t crc,
|
|
|
72 const uint8_t *buffer, size_t length) av_pure;
|
|
|
73
|
|
|
74 #endif /* AVUTIL_CRC_H */
|
