decomp_wlsb.h File Reference

Window-based Least Significant Bits (W-LSB) decoding. More...

#include "interval.h"
#include <stdlib.h>
#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>

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Data Structures
struct	rohc_lsb_decode
	The Least Significant Bits (LSB) decoding object. More...
struct	rohc_lsb_field32
struct	rohc_lsb_field16
struct	rohc_lsb_field8

Enumerations
enum	rohc_lsb_ref_t { ROHC_LSB_REF_MINUS_1 = 0, ROHC_LSB_REF_0 = 1, ROHC_LSB_REF_MAX }

Functions
void	rohc_lsb_init (struct rohc_lsb_decode *const lsb, const size_t max_len)
	Initialize a given Least Significant Bits (LSB) decoding context. More...
bool	rohc_lsb_is_ready (const struct rohc_lsb_decode *const lsb)
	Is the LSB decoding context ready to decode a compressed value. More...
bool	rohc_lsb_decode (const struct rohc_lsb_decode *const lsb, const rohc_lsb_ref_t ref_type, const uint32_t v_ref_d_offset, const uint32_t m, const size_t k, const rohc_lsb_shift_t p, uint32_t *const decoded)
	Decode a LSB-encoded value. More...
void	rohc_lsb_set_ref (struct rohc_lsb_decode *const lsb, const uint32_t v_ref_d, const bool keep_ref_minus_1)
	Update the LSB reference value. More...
uint32_t	rohc_lsb_get_ref (const struct rohc_lsb_decode *const lsb, const rohc_lsb_ref_t ref_type)
	Get the current LSB reference value (ref 0) More...

Detailed Description

Window-based Least Significant Bits (W-LSB) decoding.

Author

Didier Barvaux didie.nosp@m.r.ba.nosp@m.rvaux.nosp@m.@tou.nosp@m.louse.nosp@m..viv.nosp@m.eris..nosp@m.com

Didier Barvaux didie.nosp@m.r@ba.nosp@m.rvaux.nosp@m..org

Enumeration Type Documentation

rohc_lsb_ref_t

enum rohc_lsb_ref_t

The different reference values for LSB decoding

Enumerator
ROHC_LSB_REF_MINUS_1	Use the 'ref -1' reference value
ROHC_LSB_REF_0	Use the 'ref 0' reference value
ROHC_LSB_REF_MAX	The number of different reference values

Function Documentation

rohc_lsb_decode()

bool rohc_lsb_decode	(	const struct rohc_lsb_decode *const	lsb,
		const rohc_lsb_ref_t	ref_type,
		const uint32_t	v_ref_d_offset,
		const uint32_t	m,
		const size_t	k,
		const rohc_lsb_shift_t	p,
		uint32_t *const	decoded
	)

Decode a LSB-encoded value.

See 4.5.1 in the RFC 3095 for details about LSB encoding.

Parameters

lsb	The LSB object used to decode
ref_type	The reference value to use to decode (used for context repair upon CRC failure)
v_ref_d_offset	The offset to apply on v_ref_d (used for context repair upon CRC failure)
m	The LSB value to decode
k	The length of the LSB value to decode
p	The shift value p used to efficiently encode/decode the values
decoded	OUT: The decoded value

Returns

true in case of success, false otherwise

rohc_lsb_get_ref()

uint32_t rohc_lsb_get_ref	(	const struct rohc_lsb_decode *const	lsb,
		const rohc_lsb_ref_t	ref_type
	)

Get the current LSB reference value (ref 0)

Parameters

lsb	The LSB object
ref_type	The reference value to retrieve

Returns

The current reference value

rohc_lsb_init()

void rohc_lsb_init	(	struct rohc_lsb_decode *const	lsb,
		const size_t	max_len
	)

Initialize a given Least Significant Bits (LSB) decoding context.

See 4.5.1 in the RFC 3095 for details about LSB encoding.

Parameters

[in,out]	lsb	The LSB decoding context to init
	max_len	The max length (in bits) of the non-compressed field

rohc_lsb_is_ready()

bool rohc_lsb_is_ready

(

const struct rohc_lsb_decode *const

lsb

)

Is the LSB decoding context ready to decode a compressed value.

Parameters

lsb	The LSB object used to decode

Returns

Whether the LSB decoding context is ready to decode a value

rohc_lsb_set_ref()

void rohc_lsb_set_ref	(	struct rohc_lsb_decode *const	lsb,
		const uint32_t	v_ref_d,
		const bool	keep_ref_minus_1
	)

Update the LSB reference value.

This function is called after a CRC success to update the last decoded value (for example, the SN value). See 4.5.1 in the RFC 3095 for details about LSB encoding.

Parameters

lsb	The LSB object
v_ref_d	The new reference value
keep_ref_minus_1	Keep ref -1 unchanged (used for SN context repair after CRC failure, see RFC3095 §5.3.2.2.5)