crc.c File Reference

#include "config.h"
#include "common.h"
#include "bswap.h"
#include "crc.h"

Go to the source code of this file.

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)
	Calculate the CRC of a block.

Variables
struct {
uint8_t   le
uint8_t   bits
uint32_t   poly
}	av_crc_table_params [AV_CRC_MAX]
static AVCRC	av_crc_table [AV_CRC_MAX][257]

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 43 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 76 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(), 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 90 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(), mpegts_write_section(), output_frame_end(), read_extra_header(), tta_check_crc(), write_extradata(), write_frame_footer(), write_frame_header(), and write_section_data().

Variable Documentation

uint8_t le

Definition at line 30 of file crc.c.

Referenced by av_crc_get_table(), decode_frame(), epaf_read_header(), and ircam_read_header().

uint8_t bits

Definition at line 31 of file crc.c.

Referenced by aac_sync(), ac3_compute_mantissa_size_c(), ac3_decode_transform_coeffs_ch(), adaptive_quantization(), apply_lpc(), arith2_get_consumed_bytes(), arith_get_bits(), av_base64_decode(), av_crc_get_table(), av_crc_init(), av_get_bits_per_pixel(), av_get_padded_bits_per_pixel(), avpriv_copy_bits(), avpriv_copy_pce_data(), aw_parse_coords(), binkb_get_value(), binkb_read_bundle(), bit8x8_c(), bits2qp(), build_huff(), build_huff_tree(), build_table(), calc_bit_demand(), calc_rice_params(), can_safely_read(), check_slice_end(), codebook_trellis_rate(), dca_decode_frame(), dct_error(), decode_band_types(), decode_block(), decode_i2_frame(), decode_init(), decode_rgb_frame(), decode_rle(), decode_spectrum_and_dequant(), decode_subframe(), decode_vbmtree(), dequant(), dnxhd_calc_ac_bits(), dnxhd_encode_rdo(), dnxhd_find_qscale(), dvbsub_read_2bit_string(), dvbsub_read_4bit_string(), dvbsub_read_8bit_string(), encode_block(), encode_frame(), encode_picture(), encode_residual_ch(), encode_rgb_frame(), encode_thread(), estimate_acs(), estimate_dcs(), estimate_slice_plane(), extend_code(), ff_acelp_fc_pulse_per_track(), ff_decode_10_pulses_35bits(), ff_eac3_decode_transform_coeffs_aht_ch(), ff_h263_encode_motion(), ff_h264_decode_mb_cabac(), ff_huffyuv_generate_bits_table(), ff_mpeg1_encode_init(), ff_mpeg4_merge_partitions(), ff_MPV_encode_picture(), ff_rate_control_init(), ff_rate_estimate_qscale(), ff_rv34_decode_init(), fillPlane16(), find_slice_quant(), find_subframe_rice_params(), fold(), gb_get_v(), generate_joint_tables(), get_bits_diff(), get_mvdata_interlaced(), get_qscale(), hScale16To19_c(), imc_decode_block(), init_pass2(), init_static(), init_uni_h263_rl_tab(), init_uni_mpeg4_rl_tab(), ivi_create_huff_from_desc(), lag_decode_prob(), ljpeg_decode_yuv_scan(), main(), mp_decode_layer2(), mpc8_dec_enum(), mpc8_decode_frame(), mpeg1_encode_motion(), mpeg4_decode_partition_a(), msmpeg4v2_encode_motion(), mss4_init_vlc(), nelly_decode_block(), put_codebook_header(), quantize(), rd8x8_c(), read_argb_line(), read_code_table(), read_dct_coeffs(), read_huffman_tables(), read_quant_spectral_coeffs(), read_rgb24_component_line(), read_sbr_envelope(), s302m_parse_frame_header(), scale_vector(), search_for_quantizers_twoloop(), seq_decode_op1(), smka_decode_frame(), vorbis_parse_setup_hdr_floors(), vp56_rac_renorm(), wp_log2(), xan_unpack_luma(), and zero_extend().

uint32_t poly

Definition at line 32 of file crc.c.

Referenced by av_crc_get_table(), and mul_poly().

struct { ... } av_crc_table_params[AV_CRC_MAX]

Initial value:

= {
    [AV_CRC_8_ATM]      = { 0,  8,       0x07 },
    [AV_CRC_16_ANSI]    = { 0, 16,     0x8005 },
    [AV_CRC_16_CCITT]   = { 0, 16,     0x1021 },
    [AV_CRC_32_IEEE]    = { 0, 32, 0x04C11DB7 },
    [AV_CRC_32_IEEE_LE] = { 1, 32, 0xEDB88320 },
}

Referenced by av_crc_get_table().

AVCRC av_crc_table[AV_CRC_MAX][257]

static

Definition at line 40 of file crc.c.

Referenced by av_crc_get_table().