forked from KolibriOS/kolibrios
86 lines
2.6 KiB
C
86 lines
2.6 KiB
C
/*
|
|
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef AVUTIL_CRC_H
|
|
#define AVUTIL_CRC_H
|
|
|
|
#include <stdint.h>
|
|
#include <stddef.h>
|
|
#include "attributes.h"
|
|
|
|
/**
|
|
* @defgroup lavu_crc32 CRC32
|
|
* @ingroup lavu_crypto
|
|
* @{
|
|
*/
|
|
|
|
typedef uint32_t AVCRC;
|
|
|
|
typedef enum {
|
|
AV_CRC_8_ATM,
|
|
AV_CRC_16_ANSI,
|
|
AV_CRC_16_CCITT,
|
|
AV_CRC_32_IEEE,
|
|
AV_CRC_32_IEEE_LE, /*< reversed bitorder version of AV_CRC_32_IEEE */
|
|
AV_CRC_24_IEEE = 12,
|
|
AV_CRC_MAX, /*< Not part of public API! Do not use outside libavutil. */
|
|
}AVCRCId;
|
|
|
|
/**
|
|
* Initialize a CRC table.
|
|
* @param ctx must be an array of size sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
|
|
* @param le If 1, the lowest bit represents the coefficient for the highest
|
|
* exponent of the corresponding polynomial (both for poly and
|
|
* actual CRC).
|
|
* If 0, you must swap the CRC parameter and the result of av_crc
|
|
* if you need the standard representation (can be simplified in
|
|
* most cases to e.g. bswap16):
|
|
* av_bswap32(crc << (32-bits))
|
|
* @param bits number of bits for the CRC
|
|
* @param poly generator polynomial without the x**bits coefficient, in the
|
|
* representation as specified by le
|
|
* @param ctx_size size of ctx in bytes
|
|
* @return <0 on failure
|
|
*/
|
|
int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size);
|
|
|
|
/**
|
|
* Get an initialized standard CRC table.
|
|
* @param crc_id ID of a standard CRC
|
|
* @return a pointer to the CRC table or NULL on failure
|
|
*/
|
|
const AVCRC *av_crc_get_table(AVCRCId crc_id);
|
|
|
|
/**
|
|
* Calculate the CRC of a block.
|
|
* @param crc CRC of previous blocks if any or initial value for CRC
|
|
* @return CRC updated with the data from the given block
|
|
*
|
|
* @see av_crc_init() "le" parameter
|
|
*/
|
|
uint32_t av_crc(const AVCRC *ctx, uint32_t crc,
|
|
const uint8_t *buffer, size_t length) av_pure;
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
#endif /* AVUTIL_CRC_H */
|