t4.c File Reference

#include <stdlib.h>
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <memory.h>
#include <string.h>
#include "floating_fudge.h"
#include <tiffio.h>
#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/bit_operations.h"
#include "spandsp/async.h"
#include "spandsp/t4.h"
#include "faxfont.h"
#include "t4_states.h"


Classes
struct	t4_table_entry_t
struct	t4_run_table_entry_t
Defines
#define	CM_PER_INCH 2.54f
#define	STATE_TRACE(...)
#define	pixel_is_black(x, bit) (((x)[(bit) >> 3] << ((bit) & 7)) & 0x80)
Enumerations
enum	{ S_Null = 0, S_Pass = 1, S_Horiz = 2, S_Vert = 3, S_Ext = 4, S_TermW = 5, S_TermB = 6, S_MakeUpW = 7, S_MakeUpB = 8, S_MakeUp = 9, S_EOL = 10 }
Functions
int	t4_rx_end_page (t4_state_t *s)
	Complete the reception of a page.
int	t4_rx_put_bit (t4_state_t *s, int bit)
	Put a bit of the current document page.
int	t4_rx_put_byte (t4_state_t *s, uint8_t byte)
	Put a byte of the current document page.
int	t4_rx_put_chunk (t4_state_t *s, const uint8_t buf[], int len)
	Put a byte of the current document page.
int	t4_rx_set_row_write_handler (t4_state_t s, t4_row_write_handler_t handler, void user_data)
t4_state_t *	t4_rx_init (t4_state_t s, const char file, int output_encoding)
	Prepare for reception of a document.
int	t4_rx_start_page (t4_state_t *s)
	Prepare to receive the next page of the current document.
int	t4_rx_delete (t4_state_t *s)
	End reception of a document. Tidy up, close the file and free the context. This should be used to end T.4 reception started with t4_rx_init.
int	t4_rx_end (t4_state_t *s)
	End reception of a document. Tidy up and close the file. This should be used to end T.4 reception started with t4_rx_init.
void	t4_rx_set_rx_encoding (t4_state_t *s, int encoding)
	Set the encoding for the received data.
void	t4_rx_set_image_width (t4_state_t *s, int width)
	Set the expected width of the received image, in pixel columns.
void	t4_rx_set_y_resolution (t4_state_t *s, int resolution)
	Set the row-to-row (y) resolution to expect for a received image.
void	t4_rx_set_x_resolution (t4_state_t *s, int resolution)
	Set the column-to-column (x) resolution to expect for a received image.
void	t4_rx_set_dcs (t4_state_t s, const char dcs)
	Set the DCS information of the fax, for inclusion in the file.
void	t4_rx_set_sub_address (t4_state_t s, const char sub_address)
	Set the sub-address of the fax, for inclusion in the file.
void	t4_rx_set_far_ident (t4_state_t s, const char ident)
	Set the identity of the remote machine, for inclusion in the file.
void	t4_rx_set_vendor (t4_state_t s, const char vendor)
	Set the vendor of the remote machine, for inclusion in the file.
void	t4_rx_set_model (t4_state_t s, const char model)
	Set the model of the remote machine, for inclusion in the file.
int	t4_tx_set_row_read_handler (t4_state_t s, t4_row_read_handler_t handler, void user_data)
t4_state_t *	t4_tx_init (t4_state_t s, const char file, int start_page, int stop_page)
	Prepare for transmission of a document.
int	t4_tx_start_page (t4_state_t *s)
	Prepare to send the next page of the current document.
int	t4_tx_more_pages (t4_state_t *s)
	Check for the existance of the next page. This information can be needed before it is determined that the current page is finished with.
int	t4_tx_restart_page (t4_state_t *s)
	Prepare the current page for a resend.
int	t4_tx_end_page (t4_state_t *s)
	Complete the sending of a page.
int	t4_tx_get_bit (t4_state_t *s)
	Get the next bit of the current document page. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added where appropriate.
int	t4_tx_get_byte (t4_state_t *s)
	Get the next byte of the current document page. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added where appropriate.
int	t4_tx_get_chunk (t4_state_t *s, uint8_t buf[], int max_len)
	Get the next chunk of the current document page. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added where appropriate.
int	t4_tx_check_bit (t4_state_t *s)
	Return the next bit of the current document page, without actually moving forward in the buffer. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added.
int	t4_tx_delete (t4_state_t *s)
	End the transmission of a document. Tidy up, close the file and free the context. This should be used to end T.4 transmission started with t4_tx_init.
int	t4_tx_end (t4_state_t *s)
	End the transmission of a document. Tidy up and close the file. This should be used to end T.4 transmission started with t4_tx_init.
void	t4_tx_set_tx_encoding (t4_state_t *s, int encoding)
	Set the encoding for the encoded data.
void	t4_tx_set_min_row_bits (t4_state_t *s, int bits)
	Set the minimum number of encoded bits per row. This allows the makes the encoding process to be set to comply with the minimum row time specified by a remote receiving machine.
void	t4_tx_set_local_ident (t4_state_t s, const char ident)
	Set the identity of the local machine, for inclusion in page headers.
void	t4_tx_set_header_info (t4_state_t s, const char info)
	Set the header info.
int	t4_tx_get_y_resolution (t4_state_t *s)
	Get the row-to-row (y) resolution of the current page.
int	t4_tx_get_x_resolution (t4_state_t *s)
	Get the column-to-column (x) resolution of the current page.
int	t4_tx_get_image_width (t4_state_t *s)
	Get the width of the current page, in pixel columns.
int	t4_tx_get_pages_in_file (t4_state_t *s)
	Get the number of pages in the file.
void	t4_get_transfer_statistics (t4_state_t s, t4_stats_t t)
	Get the current transfer statistics.
const char *	t4_encoding_to_str (int encoding)
	Get the short text name of an encoding format.

Detailed Description

Function Documentation

const char* t4_encoding_to_str ( int encoding )

Get the short text name of an encoding format.

Parameters:

encoding

The encoding type.

Returns:: A pointer to the string.

void t4_get_transfer_statistics	(	t4_state_t *	s,
		t4_stats_t *	t
	)

Get the current transfer statistics.

Get the current image transfer statistics.

Parameters:

	s	The T.4 context.
	t	A pointer to a statistics structure.

References t4_state_t::bad_rows, t4_stats_t::bad_rows, t4_stats_t::encoding, t4_state_t::image_length, t4_state_t::image_width, t4_stats_t::length, t4_state_t::line_encoding, t4_state_t::line_image_size, t4_stats_t::line_image_size, t4_state_t::longest_bad_row_run, t4_stats_t::longest_bad_row_run, t4_state_t::pages_in_file, t4_stats_t::pages_in_file, t4_state_t::pages_transferred, t4_stats_t::pages_transferred, t4_state_t::start_page, t4_stats_t::width, t4_state_t::x_resolution, t4_stats_t::x_resolution, t4_state_t::y_resolution, and t4_stats_t::y_resolution.

Referenced by t30_get_transfer_statistics().

int t4_rx_delete ( t4_state_t * s )

End reception of a document. Tidy up, close the file and free the context. This should be used to end T.4 reception started with t4_rx_init.

Parameters:

s

The T.4 receive context.

Returns:: 0 for success, otherwise -1.

References t4_rx_end().

int t4_rx_end ( t4_state_t * s )

End reception of a document. Tidy up and close the file. This should be used to end T.4 reception started with t4_rx_init.

Parameters:

s

The T.4 context.

Returns:: 0 for success, otherwise -1.

References t4_state_t::rx, and t4_state_t::tiff_file.

Referenced by t30_release(), and t4_rx_delete().

int t4_rx_end_page ( t4_state_t * s )

Complete the reception of a page.

Parameters:

s

The T.4 receive context.

Returns:: 0 for success, otherwise -1.

References t4_state_t::bytes_per_row, t4_state_t::consecutive_eols, t4_state_t::curr_bad_row_run, t4_state_t::file, t4_state_t::image_buffer, t4_state_t::image_length, t4_state_t::image_size, t4_state_t::line_encoding, t4_state_t::logging, t4_state_t::longest_bad_row_run, t4_state_t::row_write_handler, t4_state_t::row_write_user_data, t4_state_t::rx_bits, t4_state_t::rx_bitstream, t4_state_t::rx_skip_bits, span_log(), t4_rx_put_bit(), and t4_state_t::tiff_file.

t4_state_t* t4_rx_init	(	t4_state_t *	s,
		const char *	file,
		int	output_encoding
	)

Prepare for reception of a document.

Parameters:

	s	The T.4 context.
	file	The name of the file to be received.
	output_encoding	The output encoding.

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

References t4_state_t::bytes_per_row, t4_state_t::file, t4_state_t::image_buffer, t4_state_t::image_buffer_size, t4_state_t::image_width, t4_state_t::logging, t4_state_t::output_compression, t4_state_t::output_t4_options, t4_state_t::pages_in_file, t4_state_t::pages_transferred, t4_state_t::rx, span_log(), t4_state_t::start_page, t4_state_t::stop_page, t4_state_t::x_resolution, and t4_state_t::y_resolution.

int t4_rx_put_bit	(	t4_state_t *	s,
		int	bit
	)

Put a bit of the current document page.

Parameters:

	s	The T.4 context.
	bit	The data bit.

Returns:: TRUE when the bit ends the document page, otherwise FALSE.

Referenced by t30_non_ecm_put_bit(), and t4_rx_end_page().

int t4_rx_put_byte	(	t4_state_t *	s,
		uint8_t	byte
	)

Put a byte of the current document page.

Parameters:

	s	The T.4 context.
	byte	The data byte.

Returns:: TRUE when the byte ends the document page, otherwise FALSE.

Referenced by t30_non_ecm_put_byte().

int t4_rx_put_chunk	(	t4_state_t *	s,
		const uint8_t	buf[],
		int	len
	)

Put a byte of the current document page.

Parameters:

	s	The T.4 context.
	buf	The buffer containing the chunk.
	len	The length of the chunk.

Returns:: TRUE when the byte ends the document page, otherwise FALSE.

Referenced by t30_non_ecm_put_chunk().

void t4_rx_set_dcs	(	t4_state_t *	s,
		const char *	dcs
	)

Set the DCS information of the fax, for inclusion in the file.

Parameters:

	s	The T.4 context.
	dcs	The DCS information, formatted as an ASCII string.

References t4_state_t::dcs.

void t4_rx_set_far_ident	(	t4_state_t *	s,
		const char *	ident
	)

Set the identity of the remote machine, for inclusion in the file.

Parameters:

	s	The T.4 context.
	ident	The identity string.

References t4_state_t::far_ident.

void t4_rx_set_image_width	(	t4_state_t *	s,
		int	width
	)

Set the expected width of the received image, in pixel columns.

Parameters:

	s	The T.4 context.
	width	The number of pixels across the image.

References t4_state_t::image_width.

void t4_rx_set_model	(	t4_state_t *	s,
		const char *	model
	)

Set the model of the remote machine, for inclusion in the file.

Parameters:

	s	The T.4 context.
	model	The model string, or NULL.

References t4_state_t::model.

void t4_rx_set_rx_encoding	(	t4_state_t *	s,
		int	encoding
	)

Set the encoding for the received data.

Parameters:

	s	The T.4 context.
	encoding	The encoding.

References t4_state_t::line_encoding.

void t4_rx_set_sub_address	(	t4_state_t *	s,
		const char *	sub_address
	)

Set the sub-address of the fax, for inclusion in the file.

Parameters:

	s	The T.4 context.
	sub_address	The sub-address string.

References t4_state_t::sub_address.

void t4_rx_set_vendor	(	t4_state_t *	s,
		const char *	vendor
	)

Set the vendor of the remote machine, for inclusion in the file.

Parameters:

	s	The T.4 context.
	vendor	The vendor string, or NULL.

References t4_state_t::vendor.

void t4_rx_set_x_resolution	(	t4_state_t *	s,
		int	resolution
	)

Set the column-to-column (x) resolution to expect for a received image.

Parameters:

	s	The T.4 context.
	resolution	The resolution, in pixels per metre.

References t4_state_t::x_resolution.

void t4_rx_set_y_resolution	(	t4_state_t *	s,
		int	resolution
	)

Set the row-to-row (y) resolution to expect for a received image.

Parameters:

	s	The T.4 context.
	resolution	The resolution, in pixels per metre.

References t4_state_t::y_resolution.

int t4_rx_start_page ( t4_state_t * s )

Prepare to receive the next page of the current document.

Parameters:

s

The T.4 context.

Returns:: zero for success, -1 for failure.

References t4_state_t::a0, t4_state_t::a_cursor, t4_state_t::b1, t4_state_t::b_cursor, t4_state_t::bad_rows, t4_state_t::black_white, t4_state_t::bytes_per_row, t4_state_t::consecutive_eols, t4_state_t::cur_runs, t4_state_t::curr_bad_row_run, t4_state_t::image_length, t4_state_t::image_size, t4_state_t::image_width, t4_state_t::its_black, t4_state_t::last_row_starts_at, t4_state_t::line_encoding, t4_state_t::line_image_size, t4_state_t::logging, t4_state_t::longest_bad_row_run, t4_state_t::max_row_bits, t4_state_t::min_row_bits, t4_state_t::page_start_time, t4_state_t::ref_runs, t4_state_t::ref_steps, t4_state_t::row_bits, t4_state_t::row_is_2d, t4_state_t::row_len, t4_state_t::run_length, t4_state_t::rx_bits, t4_state_t::rx_bitstream, t4_state_t::rx_skip_bits, span_log(), t4_state_t::tiff_file, t4_state_t::tx_bits, and t4_state_t::tx_bitstream.

int t4_tx_check_bit ( t4_state_t * s )

Return the next bit of the current document page, without actually moving forward in the buffer. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added.

Parameters:

s

The T.4 context.

Returns:: The next bit (i.e. 0 or 1). For the last bit of data, bit 1 is set (i.e. the returned value is 2 or 3).

References t4_state_t::bit_pos, t4_state_t::bit_ptr, t4_state_t::image_buffer, t4_state_t::image_size, and SIG_STATUS_END_OF_DATA.

int t4_tx_delete ( t4_state_t * s )

End the transmission of a document. Tidy up, close the file and free the context. This should be used to end T.4 transmission started with t4_tx_init.

Parameters:

s

The T.4 context.

Returns:: 0 for success, otherwise -1.

References t4_tx_end().

int t4_tx_end ( t4_state_t * s )

End the transmission of a document. Tidy up and close the file. This should be used to end T.4 transmission started with t4_tx_init.

Parameters:

s

The T.4 context.

Returns:: 0 for success, otherwise -1.

References t4_state_t::rx, and t4_state_t::tiff_file.

Referenced by t30_release(), and t4_tx_delete().

int t4_tx_end_page ( t4_state_t * s )

Complete the sending of a page.

Parameters:

s

The T.4 context.

Returns:: zero for success, -1 for failure.

References t4_state_t::pages_transferred.

int t4_tx_get_bit ( t4_state_t * s )

Get the next bit of the current document page. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added where appropriate.

Parameters:

s

The T.4 context.

Returns:: The next bit (i.e. 0 or 1). For the last bit of data, bit 1 is set (i.e. the returned value is 2 or 3).

References t4_state_t::bit_pos, t4_state_t::bit_ptr, t4_state_t::image_buffer, t4_state_t::image_size, and SIG_STATUS_END_OF_DATA.

Referenced by t30_non_ecm_get_bit().

int t4_tx_get_byte ( t4_state_t * s )

Get the next byte of the current document page. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added where appropriate.

Parameters:

s

The T.4 context.

Returns:: The next byte. For the last byte of data, bit 8 is set. In this case, one or more bits of the byte may be padded with zeros, to complete the byte.

References t4_state_t::bit_ptr, t4_state_t::image_buffer, and t4_state_t::image_size.

Referenced by t30_non_ecm_get_byte().

int t4_tx_get_chunk	(	t4_state_t *	s,
		uint8_t	buf[],
		int	max_len
	)

Get the next chunk of the current document page. The document will be padded for the current minimum scan line time. If the file does not contain an RTC (return to control) code at the end of the page, one will be added where appropriate.

Parameters:

	s	The T.4 context.
	buf	The buffer into which the chunk is to written.
	max_len	The maximum length of the chunk.

Returns:: The actual length of the chunk. If this is less than max_len it indicates that the end of the document has been reached.

References t4_state_t::bit_ptr, t4_state_t::image_buffer, and t4_state_t::image_size.

Referenced by t30_non_ecm_get_chunk().

int t4_tx_get_image_width ( t4_state_t * s )

Get the width of the current page, in pixel columns.

Parameters:

s

The T.4 context.

Returns:: The number of columns.

References t4_state_t::image_width.

int t4_tx_get_pages_in_file ( t4_state_t * s )

Get the number of pages in the file.

Parameters:

s

The T.4 context.

Returns:: The number of pages, or -1 if there is an error.

References t4_state_t::pages_in_file, t4_state_t::pages_transferred, and t4_state_t::tiff_file.

int t4_tx_get_x_resolution ( t4_state_t * s )

Get the column-to-column (x) resolution of the current page.

Parameters:

s

The T.4 context.

Returns:: The resolution, in pixels per metre.

References t4_state_t::x_resolution.

int t4_tx_get_y_resolution ( t4_state_t * s )

Get the row-to-row (y) resolution of the current page.

Parameters:

s

The T.4 context.

Returns:: The resolution, in pixels per metre.

References t4_state_t::y_resolution.

t4_state_t* t4_tx_init	(	t4_state_t *	s,
		const char *	file,
		int	start_page,
		int	stop_page
	)

Prepare for transmission of a document.

Parameters:

	s	The T.4 context.
	file	The name of the file to be sent.
	start_page	The first page to send. -1 for no restriction.
	stop_page	The last page to send. -1 for no restriction.

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

References t4_state_t::bytes_per_row, t4_state_t::cur_runs, t4_state_t::file, t4_state_t::image_buffer_size, t4_state_t::image_width, t4_state_t::logging, t4_state_t::max_rows_to_next_1d_row, t4_state_t::pages_in_file, t4_state_t::pages_transferred, t4_state_t::ref_runs, t4_state_t::ref_steps, t4_state_t::row_buf, t4_state_t::rows_to_next_1d_row, t4_state_t::rx, span_log(), t4_state_t::start_page, and t4_state_t::stop_page.

int t4_tx_more_pages ( t4_state_t * s )

Check for the existance of the next page. This information can be needed before it is determined that the current page is finished with.

Parameters:

s

The T.4 context.

Returns:: zero for next page found, -1 for failure.

References t4_state_t::logging, t4_state_t::pages_in_file, t4_state_t::pages_transferred, span_log(), t4_state_t::stop_page, and t4_state_t::tiff_file.

int t4_tx_restart_page ( t4_state_t * s )

Prepare the current page for a resend.

Parameters:

s

The T.4 context.

Returns:: zero for success, -1 for failure.

References t4_state_t::bit_pos, and t4_state_t::bit_ptr.

void t4_tx_set_header_info	(	t4_state_t *	s,
		const char *	info
	)

Set the header info.

Set the info field, included in the header line included in each page of an encoded FAX. This is a string of up to 50 characters. Other information (date, local ident, etc.) are automatically included in the header. If the header info is set to NULL or a zero length string, no header lines will be added to the encoded FAX.

Parameters:

	s	The T.4 context.
	info	A string, of up to 50 bytes, which will form the info field.

References t4_state_t::header_info.

Referenced by t30_set_tx_page_header_info().

void t4_tx_set_local_ident	(	t4_state_t *	s,
		const char *	ident
	)

Set the identity of the local machine, for inclusion in page headers.

Parameters:

	s	The T.4 context.
	ident	The identity string.

References t4_state_t::local_ident.

Referenced by t30_set_tx_ident().

void t4_tx_set_min_row_bits	(	t4_state_t *	s,
		int	bits
	)

Set the minimum number of encoded bits per row. This allows the makes the encoding process to be set to comply with the minimum row time specified by a remote receiving machine.

Parameters: