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comparison spandsp-0.0.3/spandsp-0.0.3/src/silence_gen.c @ 5:f762bf195c4b

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import spandsp-0.0.3
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 16:00:21 +0200
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4:26cd8f1ef0b1 5:f762bf195c4b
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * silence_gen.c - A silence generator, for inserting timed silences.
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2006 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 General Public License version 2, as
14 * 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 General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: silence_gen.c,v 1.6 2006/11/19 14:07:25 steveu Exp $
26 */
27
28 /*! \file */
29
30 #ifdef HAVE_CONFIG_H
31 #include "config.h"
32 #endif
33
34 #include <inttypes.h>
35 #include <stdlib.h>
36 #include <stdio.h>
37 #include <fcntl.h>
38 #include <string.h>
39 #if defined(HAVE_TGMATH_H)
40 #include <tgmath.h>
41 #endif
42 #if defined(HAVE_MATH_H)
43 #include <math.h>
44 #endif
45 #include <assert.h>
46 #include <limits.h>
47
48 #include "spandsp/telephony.h"
49 #include "spandsp/logging.h"
50 #include "spandsp/silence_gen.h"
51
52 int silence_gen(silence_gen_state_t *s, int16_t *amp, int max_len)
53 {
54 if (s->remaining_samples != INT_MAX)
55 {
56 if (max_len > s->remaining_samples)
57 max_len = s->remaining_samples;
58 s->remaining_samples -= max_len;
59 }
60 if (INT_MAX - s->total_samples >= max_len)
61 s->total_samples += max_len;
62 memset(amp, 0, max_len*sizeof(int16_t));
63 return max_len;
64 }
65 /*- End of function --------------------------------------------------------*/
66
67 void silence_gen_always(silence_gen_state_t *s)
68 {
69 s->remaining_samples = INT_MAX;
70 }
71 /*- End of function --------------------------------------------------------*/
72
73 void silence_gen_set(silence_gen_state_t *s, int silent_samples)
74 {
75 s->remaining_samples = silent_samples;
76 s->total_samples = 0;
77 }
78 /*- End of function --------------------------------------------------------*/
79
80 void silence_gen_alter(silence_gen_state_t *s, int silent_samples)
81 {
82 /* Block negative silences */
83 if (silent_samples < 0)
84 {
85 if (-silent_samples > s->remaining_samples)
86 silent_samples = -s->remaining_samples;
87 }
88 s->remaining_samples += silent_samples;
89 s->total_samples += silent_samples;
90 }
91 /*- End of function --------------------------------------------------------*/
92
93 int silence_gen_remainder(silence_gen_state_t *s)
94 {
95 return s->remaining_samples;
96 }
97 /*- End of function --------------------------------------------------------*/
98
99 int silence_gen_generated(silence_gen_state_t *s)
100 {
101 return s->total_samples;
102 }
103 /*- End of function --------------------------------------------------------*/
104
105 silence_gen_state_t *silence_gen_init(silence_gen_state_t *s, int silent_samples)
106 {
107 memset(s, 0, sizeof(*s));
108 s->remaining_samples = silent_samples;
109 return s;
110 }
111 /*- End of function --------------------------------------------------------*/
112 /*- End of file ------------------------------------------------------------*/

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