2 * SpanDSP - a series of DSP components for telephony
4 * telephony.h - some very basic telephony definitions
6 * Written by Steve Underwood <steveu@coppice.org>
8 * Copyright (C) 2003 Steve Underwood
10 * All rights reserved.
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.
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.
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.
26 #if !defined(_SPANDSP_TELEPHONY_H_)
27 #define _SPANDSP_TELEPHONY_H_
29 #if defined(_M_IX86) || defined(_M_X64)
30 #if defined(LIBSPANDSP_EXPORTS)
31 #define SPAN_DECLARE(type) __declspec(dllexport) type __stdcall
32 #define SPAN_DECLARE_NONSTD(type) __declspec(dllexport) type __cdecl
33 #define SPAN_DECLARE_DATA __declspec(dllexport)
35 #define SPAN_DECLARE(type) __declspec(dllimport) type __stdcall
36 #define SPAN_DECLARE_NONSTD(type) __declspec(dllimport) type __cdecl
37 #define SPAN_DECLARE_DATA __declspec(dllimport)
39 #elif defined(SPANDSP_USE_EXPORT_CAPABILITY) && (defined(__GNUC__) || defined(__SUNCC__))
40 #define SPAN_DECLARE(type) __attribute__((visibility("default"))) type
41 #define SPAN_DECLARE_NONSTD(type) __attribute__((visibility("default"))) type
42 #define SPAN_DECLARE_DATA __attribute__((visibility("default")))
44 #define SPAN_DECLARE(type) /**/ type
45 #define SPAN_DECLARE_NONSTD(type) /**/ type
46 #define SPAN_DECLARE_DATA /**/
49 #define SAMPLE_RATE 8000
51 /* This is based on A-law, but u-law is only 0.03dB different */
52 #define DBM0_MAX_POWER (3.14f + 3.02f)
53 #define DBM0_MAX_SINE_POWER (3.14f)
54 /* This is based on the ITU definition of dbOv in G.100.1 */
55 #define DBOV_MAX_POWER (0.0f)
56 #define DBOV_MAX_SINE_POWER (-3.02f)
58 /*! \brief A handler for pure receive. The buffer cannot be altered. */
59 typedef int (span_rx_handler_t)(void *s, const int16_t amp[], int len);
61 /*! \brief A handler for receive, where the buffer can be altered. */
62 typedef int (span_mod_handler_t)(void *s, int16_t amp[], int len);
64 /*! \brief A handler for missing receive data fill-in. */
65 typedef int (span_rx_fillin_handler_t)(void *s, int len);
67 /*! \brief A handler for transmit, where the buffer will be filled. */
68 typedef int (span_tx_handler_t)(void *s, int16_t amp[], int max_len);
70 #define ms_to_samples(t) ((t)*(SAMPLE_RATE/1000))
71 #define us_to_samples(t) ((t)/(1000000/SAMPLE_RATE))
80 #if defined(__cplusplus)
81 /* C++ doesn't seem to have sane rounding functions/macros yet */
83 #define lrint(x) ((long int) (x))
84 #define lrintf(x) ((long int) (x))
89 /*- End of file ------------------------------------------------------------*/