134 lines
4.7 KiB
C
134 lines
4.7 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* fax.h - definitions for analogue line ITU T.30 fax processing
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2005 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id: fax.h,v 1.39 2009/03/13 12:59:26 steveu Exp $
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*/
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/*! \file */
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#if !defined(_SPANDSP_FAX_H_)
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#define _SPANDSP_FAX_H_
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/*! \page fax_page FAX over analogue modem handling
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\section fax_page_sec_1 What does it do?
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\section fax_page_sec_2 How does it work?
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*/
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typedef struct fax_state_s fax_state_t;
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#if defined(__cplusplus)
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extern "C"
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{
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#endif
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/*! Apply T.30 receive processing to a block of audio samples.
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\brief Apply T.30 receive processing to a block of audio samples.
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\param s The FAX context.
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\param amp The audio sample buffer.
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\param len The number of samples in the buffer.
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\return The number of samples unprocessed. This should only be non-zero if
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the software has reached the end of the FAX call.
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*/
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SPAN_DECLARE(int) fax_rx(fax_state_t *s, int16_t *amp, int len);
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/*! Apply fake T.30 receive processing when a block of audio samples is missing (e.g due
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to packet loss).
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\brief Apply fake T.30 receive processing.
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\param s The FAX context.
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\param len The number of samples to fake.
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\return The number of samples unprocessed. This should only be non-zero if
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the software has reached the end of the FAX call.
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*/
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SPAN_DECLARE(int) fax_rx_fillin(fax_state_t *s, int len);
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/*! Apply T.30 transmit processing to generate a block of audio samples.
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\brief Apply T.30 transmit processing to generate a block of audio samples.
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\param s The FAX context.
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\param amp The audio sample buffer.
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\param max_len The number of samples to be generated.
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\return The number of samples actually generated. This will be zero when
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there is nothing to send.
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*/
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SPAN_DECLARE(int) fax_tx(fax_state_t *s, int16_t *amp, int max_len);
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/*! Select whether silent audio will be sent when FAX transmit is idle.
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\brief Select whether silent audio will be sent when FAX transmit is idle.
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\param s The FAX context.
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\param transmit_on_idle TRUE if silent audio should be output when the FAX transmitter is
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idle. FALSE to transmit zero length audio when the FAX transmitter is idle. The default
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behaviour is FALSE.
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*/
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SPAN_DECLARE(void) fax_set_transmit_on_idle(fax_state_t *s, int transmit_on_idle);
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/*! Select whether talker echo protection tone will be sent for the image modems.
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\brief Select whether TEP will be sent for the image modems.
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\param s The FAX context.
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\param use_tep TRUE if TEP should be sent.
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*/
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SPAN_DECLARE(void) fax_set_tep_mode(fax_state_t *s, int use_tep);
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/*! Get a pointer to the T.30 engine associated with a FAX context.
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\brief Get a pointer to the T.30 engine associated with a FAX context.
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\param s The FAX context.
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\return A pointer to the T.30 context, or NULL.
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*/
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SPAN_DECLARE(t30_state_t *) fax_get_t30_state(fax_state_t *s);
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/*! Get a pointer to the logging context associated with a FAX context.
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\brief Get a pointer to the logging context associated with a FAX context.
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\param s The FAX context.
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\return A pointer to the logging context, or NULL.
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*/
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SPAN_DECLARE(logging_state_t *) fax_get_logging_state(fax_state_t *s);
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/*! Initialise a FAX context.
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\brief Initialise a FAX context.
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\param s The FAX context.
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\param calling_party TRUE if the context is for a calling party. FALSE if the
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context is for an answering party.
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\return A pointer to the FAX context, or NULL if there was a problem.
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*/
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SPAN_DECLARE(fax_state_t *) fax_init(fax_state_t *s, int calling_party);
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/*! Release a FAX context.
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\brief Release a FAX context.
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\param s The FAX context.
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\return 0 for OK, else -1. */
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SPAN_DECLARE(int) fax_release(fax_state_t *s);
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/*! Free a FAX context.
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\brief Free a FAX context.
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\param s The FAX context.
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\return 0 for OK, else -1. */
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SPAN_DECLARE(int) fax_free(fax_state_t *s);
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#if defined(__cplusplus)
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}
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#endif
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#endif
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/*- End of file ------------------------------------------------------------*/
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