/usr/include/spandsp/silence_gen.h is in libspandsp-dev 0.0.6-2+b2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | /*
* SpanDSP - a series of DSP components for telephony
*
* silence_gen.c - A silence generator, for inserting timed silences.
*
* Written by Steve Underwood <steveu@coppice.org>
*
* Copyright (C) 2006 Steve Underwood
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#if !defined(_SPANDSP_SILENCE_GEN_H_)
#define _SPANDSP_SILENCE_GEN_H_
typedef struct silence_gen_state_s silence_gen_state_t;
#if defined(__cplusplus)
extern "C"
{
#endif
/*! Generate a block of silent audio samples.
\brief Generate a block of silent audio samples.
\param s The silence generator context.
\param amp The audio sample buffer.
\param max_len The number of samples to be generated.
\return The number of samples actually generated. This will be zero when
there is nothing to send.
*/
SPAN_DECLARE_NONSTD(int) silence_gen(silence_gen_state_t *s, int16_t *amp, int max_len);
/*! Set a silence generator context to output continuous silence.
\brief Set a silence generator context to output continuous silence.
\param s The silence generator context.
*/
SPAN_DECLARE(void) silence_gen_always(silence_gen_state_t *s);
/*! Set a silence generator context to output a specified period of silence.
\brief Set a silence generator context to output a specified period of silence.
\param s The silence generator context.
\param silent_samples The number of samples to be generated.
*/
SPAN_DECLARE(void) silence_gen_set(silence_gen_state_t *s, int silent_samples);
/*! Alter the period of a silence generator context by a specified amount.
\brief Alter the period of a silence generator context by a specified amount.
\param s The silence generator context.
\param silent_samples The number of samples to change the setting by. A positive number
increases the duration. A negative number reduces it. The duration
is prevented from going negative.
*/
SPAN_DECLARE(void) silence_gen_alter(silence_gen_state_t *s, int silent_samples);
/*! Find how long a silence generator context has to run.
\brief Find how long a silence generator context has to run.
\param s The silence generator context.
\return The number of samples remaining.
*/
SPAN_DECLARE(int) silence_gen_remainder(silence_gen_state_t *s);
/*! Find the total silence generated to date by a silence generator context.
\brief Find the total silence generated to date.
\param s The silence generator context.
\return The number of samples generated.
*/
SPAN_DECLARE(int) silence_gen_generated(silence_gen_state_t *s);
/*! Change the status reporting function associated with a silence generator context.
\brief Change the status reporting function associated with a silence generator context.
\param s The silence generator context.
\param handler The callback routine used to report status changes.
\param user_data An opaque pointer. */
SPAN_DECLARE(void) silence_gen_status_handler(silence_gen_state_t *s, modem_status_func_t handler, void *user_data);
/*! Initialise a timed silence generator context.
\brief Initialise a timed silence generator context.
\param s The silence generator context.
\param silent_samples The initial number of samples to set the silence to.
\return A pointer to the silence generator context.
*/
SPAN_DECLARE(silence_gen_state_t *) silence_gen_init(silence_gen_state_t *s, int silent_samples);
SPAN_DECLARE(int) silence_gen_release(silence_gen_state_t *s);
SPAN_DECLARE(int) silence_gen_free(silence_gen_state_t *s);
/* The following dummy routines, to absorb data, don't really have a proper home,
so they have been put here. */
/*! A dummy routine to use as a receive callback, when we aren't really
trying to process what is received. It just absorbs and ignores the
data.
\brief Dummy receive callback.
\param user_data The context.
\param amp The signal.buffer
\param len The length of the signal buffer
\return 0.
*/
SPAN_DECLARE_NONSTD(int) span_dummy_rx(void *user_data, const int16_t amp[], int len);
/*! A dummy routine to use as a signal modifier callback, when we aren't
really trying to process the signal. It just returns without affecting
anything.
\brief Dummy signal modifier callback.
\param user_data The context.
\param amp The signal.buffer
\param len The length of the signal buffer
\return 0.
*/
SPAN_DECLARE(int) span_dummy_mod(void *user_data, int16_t amp[], int len);
/*! A dummy routine to use as a receive fillin callback, when we aren't really
trying to process what is received. It just absorbs and ignores the
request.
\brief Dummy receive fillin callback.
\param user_data The context.
\param len The length of the signal buffer
\return 0.
*/
SPAN_DECLARE_NONSTD(int) span_dummy_rx_fillin(void *user_data, int len);
#if defined(__cplusplus)
}
#endif
#endif
/*- End of file ------------------------------------------------------------*/
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