libavutil/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 AVCRCav_crc_get_table (AVCRCId crc_id)
 Get an initialized standard CRC table.
uint32_t av_crc (const AVCRC *ctx, uint32_t start_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

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 118 of file crc.c.

Referenced by ac3_decode_frame(), ac3_eac3_probe(), check_header_mismatch(), decode_frame(), doTest(), ff_crc04C11DB7_update(), ff_flac_decode_frame_header(), ff_mlp_checksum16(), ff_mlp_checksum8(), ff_mlp_restart_checksum(), mpegts_write_section(), output_frame_end(), write_frame_footer(), write_frame_header(), and write_section_data().

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 97 of file crc.c.

Referenced by ac3_decode_frame(), ac3_eac3_probe(), check_header_mismatch(), doTest(), ff_crc04C11DB7_update(), ff_flac_decode_frame_header(), mpegts_write_section(), output_frame_end(), read_specific_config(), write_frame_footer(), write_frame_header(), and write_section_data().

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 59 of file crc.c.

Referenced by av_crc_get_table(), and ff_mlp_init_crc().


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