Variable-length output buffer for compressed data. More...

Data Structures
struct	bitbuffer
	Variable-length bit buffer structure. More...

Functions
void	bitbuffer_init (bitbuffer_t *bb)
	Initialize bit buffer to empty state.

void	bitbuffer_clear (bitbuffer_t *bb)
	Clear bit buffer contents.

int	bitbuffer_append_bit (bitbuffer_t *bb, int bit)
	Append a single bit to buffer.

int	bitbuffer_append_bits (bitbuffer_t bb, const uint8_t data, size_t num_bits)
	Append multiple bits from byte array.

int	bitbuffer_append_value (bitbuffer_t *bb, uint32_t value, size_t num_bits)
	Append multiple bits from a value directly to accumulator.

int	bitbuffer_append_bitvector (bitbuffer_t bb, const bitvector_t bv)
	Append all bits from a bit vector.

size_t	bitbuffer_size (const bitbuffer_t *bb)
	Get number of bits in buffer.

size_t	bitbuffer_to_bytes (const bitbuffer_t bb, uint8_t data, size_t max_bytes)
	Convert bit buffer to byte array.

Detailed Description

Variable-length output buffer for compressed data.

Bit buffers accumulate compressed output bit-by-bit and convert to byte arrays for transmission or storage.

Function Documentation

◆ bitbuffer_append_bit()

int bitbuffer_append_bit	(	bitbuffer_t *	bb,
		int	bit
	)

Append a single bit to buffer.

Parameters

[out]	bb	Bit buffer
[in]	bit	Bit value (0 or 1)

Returns: CCSDS124_OK on success, CCSDS124_ERROR_OVERFLOW if full

Definition at line 77 of file bitbuffer.c.

References acc, acc_len, bitbuffer_flush_acc(), CCSDS124_ERROR_INVALID_ARG, CCSDS124_ERROR_OVERFLOW, CCSDS124_MAX_OUTPUT_BYTES, CCSDS124_OK, and num_bits.

Referenced by bitbuffer_append_bits(), bitbuffer_append_bitvector(), ccsds124_bit_extract(), ccsds124_bit_extract_forward(), ccsds124_compress_packet(), ccsds124_count_encode(), and ccsds124_rle_encode().

◆ bitbuffer_append_bits()

int bitbuffer_append_bits	(	bitbuffer_t *	bb,
		const uint8_t *	data,
		size_t	num_bits
	)

Append multiple bits from byte array.

Parameters

[out]	bb	Bit buffer
[in]	data	Source bytes (MSB first within each byte)
[in]	num_bits	Number of bits to append

Returns: CCSDS124_OK on success, CCSDS124_ERROR_OVERFLOW if full

Definition at line 105 of file bitbuffer.c.

References bitbuffer_append_bit(), CCSDS124_ERROR_INVALID_ARG, CCSDS124_ERROR_OVERFLOW, CCSDS124_MAX_OUTPUT_BYTES, CCSDS124_OK, and num_bits.

◆ bitbuffer_append_bitvector()

int bitbuffer_append_bitvector	(	bitbuffer_t *	bb,
		const bitvector_t *	bv
	)

Append all bits from a bit vector.

Parameters

[out]	bb	Bit buffer
[in]	bv	Bit vector to append

Returns: CCSDS124_OK on success, CCSDS124_ERROR_OVERFLOW if full

Definition at line 181 of file bitbuffer.c.

References bitbuffer_append_bit(), bitvector_get_bit(), CCSDS124_ERROR_INVALID_ARG, CCSDS124_OK, and bitvector::length.

Referenced by ccsds124_compress_packet().

◆ bitbuffer_append_value()

int bitbuffer_append_value	(	bitbuffer_t *	bb,
		uint32_t	value,
		size_t	num_bits
	)

Append multiple bits from a value directly to accumulator.

Efficiently appends up to 24 bits from a uint32_t value MSB-first. The top 'num_bits' bits of the value (shifted left) are appended.

Parameters

[out]	bb	Bit buffer
[in]	value	Value containing bits to append (left-justified)
[in]	num_bits	Number of bits to append (1-24)

Returns: CCSDS124_OK on success, CCSDS124_ERROR_OVERFLOW if full

Append multiple bits from a value directly to accumulator.

Batches bit operations to reduce function call overhead vs calling bitbuffer_append_bit() in a loop. Used by COUNT encoding lookup table.

Performance: ~2% compression speedup from this optimization. Combined with DeBruijn bit extraction and word-level operations, achieves 14-16% faster compression and 13-39% faster decompression on real-world datasets.

Parameters