t85_decode.c File Reference

#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/async.h"
#include "spandsp/timezone.h"
#include "spandsp/t4_rx.h"
#include "spandsp/t4_tx.h"
#include "spandsp/t81_t82_arith_coding.h"
#include "spandsp/t85.h"
#include "spandsp/private/logging.h"
#include "spandsp/private/t81_t82_arith_coding.h"
#include "spandsp/private/t85.h"

Defines
#define	FALSE 0
#define	TRUE (!FALSE)
Functions
void	t85_decode_rx_status (t85_decode_state_t *s, int status)
	Inform the T.85 decode engine of a status change in the signal source (end of tx, rx signal change, etc.).
int	t85_decode_put (t85_decode_state_t *s, const uint8_t data[], size_t len)
	Decode a chunk of T.85 data.
int	t85_decode_set_row_write_handler (t85_decode_state_t s, t4_row_write_handler_t handler, void user_data)
	Set the row handler routine.
int	t85_decode_set_comment_handler (t85_decode_state_t s, uint32_t max_comment_len, t4_row_write_handler_t handler, void user_data)
	Set the comment handler routine.
int	t85_decode_set_image_size_constraints (t85_decode_state_t *s, uint32_t max_xd, uint32_t max_yd)
	Set constraints on the received image size.
uint32_t	t85_decode_get_image_width (t85_decode_state_t *s)
	Get the width of the image.
uint32_t	t85_decode_get_image_length (t85_decode_state_t *s)
	Get the length of the image.
int	t85_decode_get_compressed_image_size (t85_decode_state_t *s)
	Get the size of the compressed image, in bits.
int	t85_decode_new_plane (t85_decode_state_t *s)
int	t85_decode_restart (t85_decode_state_t *s)
logging_state_t *	t85_decode_get_logging_state (t85_decode_state_t *s)
	Get the logging context associated with a T.85 decode context.
t85_decode_state_t *	t85_decode_init (t85_decode_state_t s, t4_row_write_handler_t handler, void user_data)
	Prepare to decode an image in T.85 format.
int	t85_decode_release (t85_decode_state_t *s)
int	t85_decode_free (t85_decode_state_t *s)

Detailed Description

Function Documentation

int t85_decode_get_compressed_image_size ( t85_decode_state_t * s )

Get the size of the compressed image, in bits.

Parameters:

s

The T.85 context.

Returns:: The size of the compressed image, in bits.

Referenced by t4_rx_get_transfer_statistics().

uint32_t t85_decode_get_image_length ( t85_decode_state_t * s )

Get the length of the image.

Parameters:

s

The T.85 context.

Returns:: The length of the image, in pixels.

Referenced by t4_rx_end_page(), and t4_rx_get_transfer_statistics().

uint32_t t85_decode_get_image_width ( t85_decode_state_t * s )

Get the width of the image.

Parameters:

s

The T.85 context.

Returns:: The width of the image, in pixels.

Referenced by t4_rx_get_transfer_statistics().

logging_state_t* t85_decode_get_logging_state ( t85_decode_state_t * s )

Get the logging context associated with a T.85 decode context.

Parameters:

s

The T.85 decode context.

Returns:: A pointer to the logging context

t85_decode_state_t* t85_decode_init	(	t85_decode_state_t *	s,
		t4_row_write_handler_t	handler,
		void *	user_data
	)

Prepare to decode an image in T.85 format.

Parameters:

	s	The T.85 context.
	handler	A callback routine to handle decoded image rows.
	user_data	An opaque pointer passed to handler.

Returns:: A pointer to the context, or NULL if there was a problem.

Referenced by t4_rx_set_rx_encoding().

int t85_decode_put	(	t85_decode_state_t *	s,
		const uint8_t	data[],
		size_t	len
	)

Decode a chunk of T.85 data.

Parameters:

	s	The T.85 context.
	data	The data to be decoded.
	len	The length of the data to be decoded.

Returns:: 0 for OK.

References t85_decode_state_s::bytes_per_row, t85_decode_state_s::end_of_data, T4_DECODE_ABORTED, T4_DECODE_INTERRUPT, T4_DECODE_INVALID_DATA, T4_DECODE_MORE_DATA, T4_DECODE_NOMEM, T4_DECODE_OK, T85_LRLTWO, T85_VLENGTH, and t85_decode_state_s::y.

Referenced by t4_rx_end_page(), t4_rx_put(), and t85_decode_rx_status().

void t85_decode_rx_status	(	t85_decode_state_t *	s,
		int	status
	)

Inform the T.85 decode engine of a status change in the signal source (end of tx, rx signal change, etc.).

After the final BIE byte has been delivered to t85_decode_put_xx(), it may still return T85_MORE_DATA when the T85_VLENGTH option was used, and no NEWLEN marker section has appeared yet. This is because such a BIE is not self-terminating (i.e. there could still be a NEWLEN followed by an SDNORM or SDRST at the very end of the final stripe, which needs to be processed before the final row is output. See ITU-T Recommendation T.85, Appendix I). Therefore, after the last byte has been delivered, call this routine to signal the end of the BIE. This is necessary to allow the routine to finish processing BIEs with option T85_VLENGTH that do not actually contain any NEWLEN marker section.

Parameters:

	s	The T.85 context.
	status	The type of status change which occured.

References SIG_STATUS_CARRIER_DOWN, SIG_STATUS_CARRIER_UP, SIG_STATUS_END_OF_DATA, SIG_STATUS_TRAINING_FAILED, SIG_STATUS_TRAINING_IN_PROGRESS, SIG_STATUS_TRAINING_SUCCEEDED, signal_status_to_str(), span_log(), and t85_decode_put().

int t85_decode_set_comment_handler	(	t85_decode_state_t *	s,
		uint32_t	max_comment_len,
		t4_row_write_handler_t	handler,
		void *	user_data
	)

Set the comment handler routine.

Parameters:

	s	The T.85 context.
	max_comment_len	The maximum length of comment to be passed to the handler.
	handler	A callback routine to handle decoded comment.
	user_data	An opaque pointer passed to handler.

Returns:: 0 for OK.

int t85_decode_set_image_size_constraints	(	t85_decode_state_t *	s,
		uint32_t	max_xd,
		uint32_t	max_yd
	)

Set constraints on the received image size.

A maliciously constructed T.85 image could consume too much memory, and constitute a denial of service attack on the system. This function allows constraints to be applied.

Parameters:

	s	The T.85 context.
	max_xd	The maximum permitted width of the full image, in pixels
	max_yd	The maximum permitted height of the full image, in pixels

Returns:: 0 for OK

Referenced by t4_rx_set_rx_encoding().

int t85_decode_set_row_write_handler	(	t85_decode_state_t *	s,
		t4_row_write_handler_t	handler,
		void *	user_data
	)

Set the row handler routine.

Parameters:

	s	The T.85 context.
	handler	A callback routine to handle decoded image rows.
	user_data	An opaque pointer passed to handler.

Returns:: 0 for OK.

Referenced by t4_rx_set_row_write_handler().

t85_decode.c File Reference

Defines

Functions

Detailed Description

Function Documentation