super_tone_tx.h

00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * super_tone_tx.h - Flexible telephony supervisory tone generation.
00005  *
00006  * Written by Steve Underwood <steveu@coppice.org>
00007  *
00008  * Copyright (C) 2001 Steve Underwood
00009  *
00010  * All rights reserved.
00011  *
00012  * This program is free software; you can redistribute it and/or modify
00013  * it under the terms of the GNU Lesser General Public License version 2.1,
00014  * as published by the Free Software Foundation.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License along with this program; if not, write to the Free Software
00023  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00024  *
00025  * $Id: super_tone_tx.h,v 1.17 2009/02/10 13:06:47 steveu Exp $
00026  */
00027 
00028 #if !defined(_SPANDSP_SUPER_TONE_TX_H_)
00029 #define _SPANDSP_SUPER_TONE_TX_H_
00030 
00031 /*! \page super_tone_tx_page Supervisory tone generation
00032 
00033 \section super_tone_tx_page_sec_1 What does it do?
00034 
00035 The supervisory tone generator may be configured to generate most of the world's
00036 telephone supervisory tones - things like ringback, busy, number unobtainable,
00037 and so on. It uses tree structure tone descriptions, which can deal with quite
00038 complex cadence patterns. 
00039 
00040 \section super_tone_tx_page_sec_2 How does it work?
00041 
00042 */
00043 
00044 typedef struct super_tone_tx_step_s super_tone_tx_step_t;
00045 
00046 typedef struct super_tone_tx_state_s super_tone_tx_state_t;
00047 
00048 #if defined(__cplusplus)
00049 extern "C"
00050 {
00051 #endif
00052 
00053 SPAN_DECLARE(super_tone_tx_step_t *) super_tone_tx_make_step(super_tone_tx_step_t *s,
00054                                                              float f1,
00055                                                              float l1,
00056                                                              float f2,
00057                                                              float l2,
00058                                                              int length,
00059                                                              int cycles);
00060 
00061 SPAN_DECLARE(int) super_tone_tx_free_tone(super_tone_tx_step_t *s);
00062 
00063 /*! Initialise a supervisory tone generator.
00064     \brief Initialise a supervisory tone generator.
00065     \param s The supervisory tone generator context.
00066     \param tree The supervisory tone tree to be generated.
00067     \return The supervisory tone generator context. */
00068 SPAN_DECLARE(super_tone_tx_state_t *) super_tone_tx_init(super_tone_tx_state_t *s, super_tone_tx_step_t *tree);
00069 
00070 SPAN_DECLARE(int) super_tone_tx_release(super_tone_tx_state_t *s);
00071 
00072 SPAN_DECLARE(int) super_tone_tx_free(super_tone_tx_state_t *s);
00073 
00074 /*! Generate a block of audio samples for a supervisory tone pattern.
00075     \brief Generate a block of audio samples for a supervisory tone pattern.
00076     \param s The supervisory tone context.
00077     \param amp The audio sample buffer.
00078     \param max_samples The maximum number of samples to be generated.
00079     \return The number of samples generated. */
00080 SPAN_DECLARE(int) super_tone_tx(super_tone_tx_state_t *s, int16_t amp[], int max_samples);
00081 
00082 #if defined(__cplusplus)
00083 }
00084 #endif
00085 
00086 #endif
00087 /*- End of file ------------------------------------------------------------*/

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