crc.h File Reference

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Typedefs
typedef uint32_t	AVCRC
Functions
int	av_crc_init (AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size)
	Inits a crc table.
uint32_t	av_crc (const AVCRC *ctx, uint32_t start_crc, const uint8_t *buffer, size_t length)
	Calculate the CRC of a block.
Variables
AVCRC *	av_crcEDB88320
AVCRC *	av_crc04C11DB7
AVCRC *	av_crc8005
AVCRC *	av_crc07

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Typedef Documentation

typedef uint32_t AVCRC

Definition at line 27 of file crc.h.

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Function Documentation

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

Inits a crc table.

Parameters:

	ctx	must be an array of sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
	cts_size	size of ctx in bytes
	le	if 1, lowest bit represents coefficient for highest exponent of 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): bswap_32(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

Returns:

<0 on failure

Definition at line 51 of file crc.c.

Referenced by init_crcs(), and main().

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 89 of file crc.c.

Referenced by ac3_decode_frame(), PESPacket::CalcCRC(), decode_frame(), ff_crc04C11DB7_update(), main(), mpegts_write_section(), output_frame_end(), output_frame_footer(), output_frame_header(), and write_section_data().

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Variable Documentation

AVCRC av_crcEDB88320[]

Definition at line 42 of file crc.h.

AVCRC av_crc04C11DB7[]

Definition at line 43 of file crc.h.

Referenced by PESPacket::CalcCRC(), ff_crc04C11DB7_update(), init_crcs(), mpegts_write_section(), and write_section_data().

AVCRC av_crc8005[]

Definition at line 44 of file crc.h.

Referenced by ac3_decode_frame(), init_crcs(), output_frame_end(), and output_frame_footer().

AVCRC av_crc07[]

Definition at line 45 of file crc.h.

Referenced by decode_frame(), init_crcs(), and output_frame_header().