Decoding API

CCSDS Section 5.2: Decoding primitives (inverse of encoding). More...

Functions
int	ccsds124_count_decode (bitreader_t *reader, uint32_t *value)
	Counter decoding (inverse of ccsds124_count_encode).
int	ccsds124_rle_decode (bitreader_t *reader, bitvector_t *result, size_t length)
	Run-length decoding (inverse of ccsds124_rle_encode).
int	ccsds124_bit_insert (bitreader_t *reader, bitvector_t *data, const bitvector_t *mask)
	Bit insertion (inverse of ccsds124_bit_extract).

Detailed Description

CCSDS Section 5.2: Decoding primitives (inverse of encoding).

These functions decode the encoded formats back to original values.

Function Documentation

ccsds124_bit_insert()

int ccsds124_bit_insert	(	bitreader_t *	reader,
		bitvector_t *	data,
		const bitvector_t *	mask
	)

Bit insertion (inverse of ccsds124_bit_extract).

Inserts extracted bits back into a vector at mask positions.

Parameters

[in,out]	reader	Bit reader (position advanced)
[out]	data	Destination data vector
[in]	mask	Mask indicating insertion positions

Returns

CCSDS124_OK on success, error code otherwise

Definition at line 287 of file decompress.c.

References bitreader_read_bit(), bitreader_remaining(), bitvector_get_set_positions(), bitvector_hamming_weight(), bitvector_set_bit(), CCSDS124_ERROR_INVALID_ARG, CCSDS124_ERROR_UNDERFLOW, CCSDS124_MAX_PACKET_LENGTH, CCSDS124_OK, and bitvector::length.

Referenced by ccsds124_decompress_packet_internal().

ccsds124_count_decode()

int ccsds124_count_decode	(	bitreader_t *	reader,
		uint32_t *	value
	)

Counter decoding (inverse of ccsds124_count_encode).

Decodes a COUNT-encoded value from the bit stream.

• '0' → 1
• '10' → 0 (terminator)
• '110' + 5 bits → value + 2
• '111' + variable bits → larger values

Parameters

[in,out]	reader	Bit reader (position advanced)
[out]	value	Decoded value (0 = terminator)

Returns

CCSDS124_OK on success, error code otherwise

Definition at line 175 of file decompress.c.

References bitreader_t::bit_pos, bitreader_read_bit(), bitreader_read_bits(), bitreader_remaining(), CCSDS124_ERROR_INVALID_ARG, CCSDS124_ERROR_UNDERFLOW, and CCSDS124_OK.

Referenced by ccsds124_decompress_packet_internal(), ccsds124_discover_packet_length(), ccsds124_rle_decode(), and skip_rle_sequence_span().

ccsds124_rle_decode()

int ccsds124_rle_decode	(	bitreader_t *	reader,
		bitvector_t *	result,
		size_t	length
	)

Run-length decoding (inverse of ccsds124_rle_encode).

Decodes an RLE-encoded bit vector from the bit stream.

Parameters

[in,out]	reader	Bit reader (position advanced)
[out]	result	Decoded bit vector
[in]	length	Expected bit vector length

Returns

CCSDS124_OK on success, error code otherwise

Definition at line 251 of file decompress.c.

References bitvector_init(), bitvector_set_bit(), bitvector_zero(), ccsds124_count_decode(), CCSDS124_ERROR_INVALID_ARG, CCSDS124_ERROR_OVERFLOW, and CCSDS124_OK.

Referenced by ccsds124_decompress_packet_internal().