1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * bell_r2_mf.h - Bell MF and MFC/R2 tone generation and detection.
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2001 Steve Underwood
9  *
10  * All rights reserved.
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU Lesser General Public License version 2.1,
14  * as published by the Free Software Foundation.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public
22  * License along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  */
25 
26 #if !defined(_SPANDSP_PRIVATE_BELL_R2_MF_H_)
27 #define _SPANDSP_PRIVATE_BELL_R2_MF_H_
28 
29 /*!
30     Bell MF generator state descriptor. This defines the state of a single
31     working instance of a Bell MF generator.
32 */
33 struct bell_mf_tx_state_s
34 {
35     /*! The tone generator. */
36     tone_gen_state_t tones;
37     int current_sample;
38     union
39     {
40         queue_state_t queue;
41         uint8_t buf[QUEUE_STATE_T_SIZE(MAX_BELL_MF_DIGITS)];
42     } queue;
43 };
44 
45 /*!
46     Bell MF digit detector descriptor.
47 */
48 struct bell_mf_rx_state_s
49 {
50     /*! Optional callback funcion to deliver received digits. */
51     digits_rx_callback_t digits_callback;
52     /*! An opaque pointer passed to the callback function. */
53     void *digits_callback_data;
54     /*! Tone detector working states */
55     goertzel_state_t out[6];
56     /*! Short term history of results from the tone detection, using in persistence checking */
57     uint8_t hits[5];
58     /*! The current sample number within a processing block. */
59     int current_sample;
60 
61     /*! The number of digits which have been lost due to buffer overflows. */
62     int lost_digits;
63     /*! The number of digits currently in the digit buffer. */
64     int current_digits;
65     /*! The received digits buffer. This is a NULL terminated string. */
66     char digits[MAX_BELL_MF_DIGITS + 1];
67 };
68 
69 /*!
70     MFC/R2 tone detector descriptor.
71 */
72 struct r2_mf_tx_state_s
73 {
74     /*! The tone generator. */
75     tone_gen_state_t tone;
76     /*! True if generating forward tones, otherwise generating reverse tones. */
77     bool fwd;
78     /*! The current digit being generated. */
79     int digit;
80 };
81 
82 /*!
83     MFC/R2 tone detector descriptor.
84 */
85 struct r2_mf_rx_state_s
86 {
87     /*! Optional callback funcion to deliver received digits. */
88     tone_report_func_t callback;
89     /*! An opaque pointer passed to the callback function. */
90     void *callback_data;
91     /*! True if we are detecting forward tones. False if we are detecting backward tones */
92     bool fwd;
93     /*! Tone detector working states */
94     goertzel_state_t out[6];
95     /*! The current sample number within a processing block. */
96     int current_sample;
97     /*! The currently detected digit. */
98     int current_digit;
99 };
100 
101 #endif
102 /*- End of file ------------------------------------------------------------*/
103