v42bis.c File Reference

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <ctype.h>
#include <assert.h>
#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/bit_operations.h"
#include "spandsp/v42bis.h"
#include "spandsp/private/logging.h"
#include "spandsp/private/v42bis.h"

Defines
#define	V42BIS_N3   8 /* Character size (bits) */
#define	V42BIS_N4   256 /* Number of characters in the alphabet */
#define	V42BIS_N5   (V42BIS_N4 + V42BIS_N6) /* Index number of first dictionary entry used to store a string */
#define	V42BIS_N6   3 /* Number of control codewords */
#define	V42BIS_ESC_STEP   51
Enumerations
enum	{ V42BIS_ETM = 0, V42BIS_FLUSH = 1, V42BIS_STEPUP = 2 }
enum	{ V42BIS_ECM = 0, V42BIS_EID = 1, V42BIS_RESET = 2 }
Functions
int	v42bis_compress (v42bis_state_t *s, const uint8_t *buf, int len)
int	v42bis_compress_flush (v42bis_state_t *s)
int	v42bis_decompress (v42bis_state_t *s, const uint8_t *buf, int len)
int	v42bis_decompress_flush (v42bis_state_t *s)
void	v42bis_compression_control (v42bis_state_t *s, int mode)
v42bis_state_t *	v42bis_init (v42bis_state_t *s, int negotiated_p0, int negotiated_p1, int negotiated_p2, v42bis_frame_handler_t frame_handler, void *frame_user_data, int max_frame_len, v42bis_data_handler_t data_handler, void *data_user_data, int max_data_len)
int	v42bis_release (v42bis_state_t *s)
int	v42bis_free (v42bis_state_t *s)

---

Detailed Description

---

Function Documentation

int v42bis_compress	(	v42bis_state_t *	s,
		const uint8_t *	buf,
		int	len
	)

Compress a block of octets.

Parameters:

s	The V.42bis context.
buf	The data to be compressed.
len	The length of the data buffer.

Returns:

0

References v42bis_dict_node_t::children, v42bis_compress_state_t::compressibility_filter, v42bis_compress_state_t::compression_mode, v42bis_compress_state_t::first, v42bis_compress_state_t::handler, v42bis_dict_node_t::leaves, v42bis_compress_state_t::max_len, v42bis_dict_node_t::node_octet, v42bis_dict_node_t::parent_code, v42bis_compress_state_t::transparent, v42bis_compress_state_t::user_data, v42bis_compress_state_t::v42bis_parm_c1, v42bis_compress_state_t::v42bis_parm_c2, and v42bis_compress_state_t::v42bis_parm_c3.

int v42bis_compress_flush

(

v42bis_state_t *

s

)

Flush out any data remaining in a compression buffer.

Parameters:

s	The V.42bis context.

Returns:

0

References v42bis_compress_state_t::handler, v42bis_compress_state_t::transparent, and v42bis_compress_state_t::user_data.

void v42bis_compression_control	(	v42bis_state_t *	s,
		int	mode
	)

Set the compression mode.

Parameters:

s	The V.42bis context.
mode	One of the V.42bis compression modes - V42BIS_COMPRESSION_MODE_DYNAMIC, V42BIS_COMPRESSION_MODE_ALWAYS, V42BIS_COMPRESSION_MODE_NEVER

int v42bis_decompress	(	v42bis_state_t *	s,
		const uint8_t *	buf,
		int	len
	)

Decompress a block of octets.

Parameters:

s	The V.42bis context.
buf	The data to be decompressed.
len	The length of the data buffer.

Returns:

0

References v42bis_decompress_state_t::first, v42bis_decompress_state_t::handler, v42bis_dict_node_t::leaves, v42bis_decompress_state_t::max_len, v42bis_dict_node_t::node_octet, v42bis_dict_node_t::parent_code, v42bis_decompress_state_t::transparent, v42bis_decompress_state_t::user_data, v42bis_decompress_flush(), v42bis_decompress_state_t::v42bis_parm_c1, v42bis_decompress_state_t::v42bis_parm_c2, and v42bis_decompress_state_t::v42bis_parm_c3.

int v42bis_decompress_flush

(

v42bis_state_t *

s

)

Flush out any data remaining in the decompression buffer.

Parameters:

s	The V.42bis context.

Returns:

0

References v42bis_decompress_state_t::handler, and v42bis_decompress_state_t::user_data.

Referenced by v42bis_decompress().

int v42bis_free

(

v42bis_state_t *

s

)

Free a V.42bis context.

Parameters:

s	The V.42bis context.

Returns:

0 if OK

v42bis_state_t* v42bis_init	(	v42bis_state_t *	s,
		int	negotiated_p0,
		int	negotiated_p1,
		int	negotiated_p2,
		v42bis_frame_handler_t	frame_handler,
		void *	frame_user_data,
		int	max_frame_len,
		v42bis_data_handler_t	data_handler,
		void *	data_user_data,
		int	max_data_len
	)

Initialise a V.42bis context.

Parameters:

s	The V.42bis context.
negotiated_p0	The negotiated P0 parameter, from the V.42bis spec.
negotiated_p1	The negotiated P1 parameter, from the V.42bis spec.
negotiated_p2	The negotiated P2 parameter, from the V.42bis spec.
frame_handler	Frame callback handler.
frame_user_data	An opaque pointer passed to the frame callback handler.
max_frame_len	The maximum length that should be passed to the frame handler.
data_handler	data callback handler.
data_user_data	An opaque pointer passed to the data callback handler.
max_data_len	The maximum length that should be passed to the data handler.

Returns:

The V.42bis context.

int v42bis_release

(

v42bis_state_t *

s

)

Release a V.42bis context.

Parameters:

s	The V.42bis context.

Returns:

0 if OK