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

#include "wlsb.h"
#include "interval.h"
#include <string.h>
#include <assert.h>

Include dependency graph for wlsb.c:

Data Structures
struct	c_window
	Define a W-LSB window entry. More...
struct	c_wlsb
	Defines a W-LSB encoding object. More...
Functions
struct c_wlsb *	c_create_wlsb (const size_t bits, const size_t window_width, const rohc_lsb_shift_t p)
	Create a new Window-based Least Significant Bits (W-LSB) encoding object.
void	c_destroy_wlsb (struct c_wlsb *const wlsb)
	Destroy a Window-based LSB (W-LSB) encoding object.
void	c_add_wlsb (struct c_wlsb *const wlsb, const uint32_t sn, const uint32_t value)
	Add a value into a W-LSB encoding object.
bool	wlsb_get_k_16bits (const struct c_wlsb const wlsb, const uint16_t value, size_t const bits_nr)
	Find out the minimal number of bits of the to-be-encoded value required to be able to uniquely recreate it given the window.
bool	wlsb_get_k_32bits (const struct c_wlsb const wlsb, const uint32_t value, size_t const bits_nr)
	Find out the minimal number of bits of the to-be-encoded value required to be able to uniquely recreate it given the window.
void	c_ack_sn_wlsb (struct c_wlsb *s, const uint32_t sn)
	Acknowledge based on the Sequence Number (SN)
int	c_sum_wlsb (struct c_wlsb *s)
	Compute the sum of all the values stored in the W-LSB window.
int	c_mean_wlsb (struct c_wlsb *s)
	Compute the mean of all the values stored in the W-LSB window.

Detailed Description

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

Author:: Didier Barvaux <didier.barvaux@toulouse.viveris.com>; Didier Barvaux <didier@barvaux.org>; David Moreau from TAS; The hackers from ROHC for Linux

Function Documentation

void c_ack_sn_wlsb	(	struct c_wlsb *	s,
		const uint32_t	sn
	)

Acknowledge based on the Sequence Number (SN)

Removes all entries older than the given SN in the window.

Parameters:

s	The W-LSB object
sn	The SN to acknowledge

References c_wlsb::count, c_wlsb::oldest, c_window::sn, c_wlsb::window, and c_wlsb::window_mask.

Referenced by c_generic_feedback().

void c_add_wlsb	(	struct c_wlsb *const	wlsb,
		const uint32_t	sn,
		const uint32_t	value
	)

Add a value into a W-LSB encoding object.

Parameters:

wlsb	The W-LSB object
sn	The Sequence Number (SN) for the new entry
value	The value to base the LSB coding on

References c_wlsb::count, c_wlsb::next, c_wlsb::oldest, sn, c_window::sn, c_window::value, c_wlsb::window, c_wlsb::window_mask, and c_wlsb::window_width.

Referenced by add_scaled(), rohc_compress2(), and rohc_decompress().

struct c_wlsb* c_create_wlsb	(	const size_t	bits,
		const size_t	window_width,
		const rohc_lsb_shift_t	p
	)		`[read]`

Create a new Window-based Least Significant Bits (W-LSB) encoding object.

Parameters:

bits	The maximal number of bits for representing a value
window_width	The number of entries in the window (power of 2)
p	Shift parameter (see 4.5.2 in the RFC 3095)

Returns:: The newly-created W-LSB encoding object

References c_wlsb::bits, c_wlsb::count, c_wlsb::next, c_wlsb::oldest, c_wlsb::p, c_wlsb::window_mask, and c_wlsb::window_width.

Referenced by c_create_sc(), c_generic_create(), and c_init_header_info().

void c_destroy_wlsb ( struct c_wlsb *const wlsb )

Destroy a Window-based LSB (W-LSB) encoding object.

Parameters:

wlsb	The W-LSB object to destroy

Referenced by c_destroy_sc(), c_generic_create(), and c_generic_destroy().

int c_mean_wlsb ( struct c_wlsb * s )

Compute the mean of all the values stored in the W-LSB window.

This function is used for statistics.

Parameters:

s	The W-LSB object

Returns:: The mean over the W-LSB window

References c_wlsb::count, c_wlsb::oldest, c_window::value, c_wlsb::window, and c_wlsb::window_mask.

int c_sum_wlsb ( struct c_wlsb * s )

Compute the sum of all the values stored in the W-LSB window.

This function is used for statistics.

Parameters:

s	The W-LSB object

Returns:: The sum over the W-LSB window

References c_wlsb::count, c_wlsb::oldest, c_window::value, c_wlsb::window, and c_wlsb::window_mask.

bool wlsb_get_k_16bits	(	const struct c_wlsb *const	wlsb,
		const uint16_t	value,
		size_t *const	bits_nr
	)

Find out the minimal number of bits of the to-be-encoded value required to be able to uniquely recreate it given the window.

The function is dedicated to 16-bit fields.

Parameters:

wlsb	The W-LSB object
value	The value to encode using the LSB algorithm
bits_nr	OUT: The number of bits required to uniquely recreate the value

Returns:: true in case of success, false if the minimal number of bits can not be found

References c_wlsb::bits, c_wlsb::count, c_wlsb::oldest, c_wlsb::p, c_window::value, c_wlsb::window, and c_wlsb::window_mask.

bool wlsb_get_k_32bits	(	const struct c_wlsb *const	wlsb,
		const uint32_t	value,
		size_t *const	bits_nr
	)

Find out the minimal number of bits of the to-be-encoded value required to be able to uniquely recreate it given the window.

The function is dedicated to 32-bit fields.

Parameters:

wlsb	The W-LSB object
value	The value to encode using the LSB algorithm
bits_nr	OUT: The number of bits required to uniquely recreate the value

Returns:: true in case of success, false if the minimal number of bits can not be found

References c_wlsb::bits, c_wlsb::count, c_wlsb::oldest, c_wlsb::p, c_window::value, c_wlsb::window, and c_wlsb::window_mask.

Referenced by nb_bits_scaled().

Data Structures

Functions

Detailed Description

Function Documentation