FFmpeg: libavutil/crc.h File Reference

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Typedefs | Enumerations | Functions

crc.h File Reference

#include <stdint.h>
#include <stddef.h>
#include "attributes.h"

Go to the source code of this file.

Typedefs

typedef uint32_t AVCRC

Enumerations

enum AVCRCId {
AV_CRC_8_ATM, AV_CRC_16_ANSI, AV_CRC_16_CCITT, AV_CRC_32_IEEE,
AV_CRC_32_IEEE_LE, AV_CRC_MAX
}

Functions

int av_crc_init (AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size)

Initialize a CRC table.

const AVCRC * av_crc_get_table (AVCRCId crc_id)

Get an initialized standard CRC table.

uint32_t av_crc (const AVCRC *ctx, uint32_t crc, const uint8_t *buffer, size_t length) av_pure

Calculate the CRC of a block.

Typedef Documentation

typedef uint32_t AVCRC

Definition at line 28 of file crc.h.

Enumeration Type Documentation

enum AVCRCId

Enumerator:: AV_CRC_8_ATM

AV_CRC_16_ANSI

AV_CRC_16_CCITT

AV_CRC_32_IEEE

AV_CRC_32_IEEE_LE

AV_CRC_MAX

Definition at line 30 of file crc.h.

Function Documentation

int av_crc_init ( AVCRC * ctx,

int le,

int bits,

uint32_t poly,

int ctx_size

)

Initialize a CRC table.

Parameters: ctx must be an array of size sizeof(AVCRC)*257 or sizeof(AVCRC)*1024

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))

bits number of bits for the CRC

poly generator polynomial without the x**bits coefficient, in the representation as specified by le

ctx_size size of ctx in bytes

Returns: <0 on failure

Definition at line 228 of file crc.c.

Referenced by av_crc_get_table(), ff_mlp_init_crc(), and ff_tak_init_crc().

const AVCRC* av_crc_get_table ( AVCRCId crc_id )

Get an initialized standard CRC table.

Parameters: crc_id ID of a standard CRC

Returns: a pointer to the CRC table or NULL on failure

Definition at line 261 of file crc.c.

Referenced by ac3_decode_frame(), ac3_eac3_probe(), check_header_mismatch(), decode_frame(), doTest(), encode_frame(), ff_crc04C11DB7_update(), ff_flac_decode_frame_header(), flac_decode_frame(), mpegts_write_section(), output_frame_end(), read_extra_header(), read_specific_config(), tta_decode_init(), write_extradata(), write_frame_footer(), write_frame_header(), and write_section_data().

uint32_t av_crc ( const AVCRC * ctx,

uint32_t crc,

const uint8_t * buffer,

size_t length

)

Calculate the CRC of a block.

Parameters: crc CRC of previous blocks if any or initial value for CRC

Returns: CRC updated with the data from the given block

See Also: av_crc_init() "le" parameter

Definition at line 275 of file crc.c.

Referenced by ac3_decode_frame(), ac3_eac3_probe(), check_header_mismatch(), decode_frame(), doTest(), encode_frame(), ff_crc04C11DB7_update(), ff_flac_decode_frame_header(), ff_mlp_checksum16(), ff_mlp_checksum8(), ff_mlp_restart_checksum(), ff_tak_check_crc(), flac_decode_frame(), mpegts_write_section(), output_frame_end(), read_extra_header(), tta_check_crc(), write_extradata(), write_frame_footer(), write_frame_header(), and write_section_data().

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