lsb.h File Reference

Least Significant Bits (LSB) encoding. More...

#include <stdlib.h>
#include <stdint.h>

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Data Structures
struct	d_lsb_decode
	Least Significant Bits decoding object. More...
Functions
void	d_lsb_init (struct d_lsb_decode *const lsb, const uint32_t v_ref_d, const short p)
	Initialize a Least Significant Bits (LSB) encoding object.
int	d_lsb_decode32 (const struct d_lsb_decode *const lsb, const uint32_t m, const size_t k, uint32_t *const decoded)
	Decode a 32-bit LSB-encoded value.
int	d_lsb_decode16 (const struct d_lsb_decode *const lsb, const uint16_t m, const size_t k, uint16_t *const decoded)
	Decode a 16-bit LSB-encoded value.
void	d_lsb_update (struct d_lsb_decode *const lsb, const uint32_t v_ref_d)
	Update the LSB reference value.
void	d_lsb_sync_ref (struct d_lsb_decode *const lsb)
	Replace the previous LSB reference value with the current one.
uint32_t	d_get_lsb_ref (struct d_lsb_decode *const lsb)
	Get the current LSB reference value.
uint32_t	d_get_lsb_old_ref (struct d_lsb_decode *const lsb)
	Get the previous LSB reference value.

---

Detailed Description

Least Significant Bits (LSB) encoding.

Author:

Didier Barvaux <didier.barvaux@toulouse.viveris.com>

The hackers from ROHC for Linux

---

Function Documentation

uint32_t d_get_lsb_old_ref

(

struct d_lsb_decode *const

lsb

)

Get the previous LSB reference value.

Parameters:

lsb	The LSB object

Returns:

The previous reference value

References d_lsb_decode::old_v_ref_d.

uint32_t d_get_lsb_ref

(

struct d_lsb_decode *const

lsb

)

Get the current LSB reference value.

Parameters:

lsb	The LSB object

Returns:

The current reference value

References d_lsb_decode::v_ref_d.

Referenced by d_generic_get_sn(), and ts_decode_scaled().

int d_lsb_decode16	(	const struct d_lsb_decode *const	lsb,
		const uint16_t	m,
		const size_t	k,
		uint16_t *const	decoded
	)

Decode a 16-bit LSB-encoded value.

See d_lsb_decode32 for details.

Parameters:

lsb	The LSB object used to decode
m	The LSB value to decode
k	The length of the LSB value to decode
decoded	OUT: The decoded value

Returns:

1 in case of success, 0 otherwise

References d_lsb_decode32().

Referenced by decode_uo0(), decode_uo1(), decode_uor2(), and main().

int d_lsb_decode32	(	const struct d_lsb_decode *const	lsb,
		const uint32_t	m,
		const size_t	k,
		uint32_t *const	decoded
	)

Decode a 32-bit LSB-encoded value.

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

Parameters:

lsb	The LSB object used to decode
m	The LSB value to decode
k	The length of the LSB value to decode
decoded	OUT: The decoded value

Returns:

1 in case of success, 0 otherwise

References f(), d_lsb_decode::p, and d_lsb_decode::v_ref_d.

Referenced by d_lsb_decode16(), and ts_decode_scaled().

void d_lsb_init	(	struct d_lsb_decode *const	lsb,
		const uint32_t	v_ref_d,
		const short	p
	)

Initialize a Least Significant Bits (LSB) encoding object.

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

Parameters:

lsb	The LSB object to initialize
v_ref_d	The reference value
p	The p value used to efficiently encode the values

References d_lsb_decode::old_v_ref_d, d_lsb_decode::p, and d_lsb_decode::v_ref_d.

Referenced by d_create_sc(), ip_decode_dynamic_ip(), main(), and rtp_decode_dynamic_rtp().

void d_lsb_sync_ref

(

struct d_lsb_decode *const

lsb

)

Replace the previous LSB reference value with the current one.

Parameters:

lsb	The LSB object

References d_lsb_decode::old_v_ref_d, and d_lsb_decode::v_ref_d.

Referenced by decode_uo0(), decode_uo1(), decode_uor2(), and ts_update_context().

void d_lsb_update	(	struct d_lsb_decode *const	lsb,
		const uint32_t	v_ref_d
	)

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

References d_lsb_decode::v_ref_d.

Referenced by decode_uo0(), decode_uo1(), decode_uor2(), main(), and ts_update_context().