Mon Jun 27 16:50:46 2011

Asterisk developer's documentation


app_echo.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2005, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  *
00021  * \brief Echo application -- play back what you hear to evaluate latency
00022  *
00023  * \author Mark Spencer <markster@digium.com>
00024  *
00025  * \ingroup applications
00026  */
00027 
00028 #include "asterisk.h"
00029 
00030 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 249947 $")
00031 
00032 #include "asterisk/file.h"
00033 #include "asterisk/module.h"
00034 #include "asterisk/channel.h"
00035 
00036 /*** DOCUMENTATION
00037    <application name="Echo" language="en_US">
00038       <synopsis>
00039          Echo audio, video, DTMF back to the calling party
00040       </synopsis>
00041       <syntax />
00042       <description>
00043          <para>Echos back any audio, video or DTMF frames read from the calling 
00044          channel back to itself. Note: If '#' detected application exits</para>
00045       </description>
00046    </application>
00047  ***/
00048 
00049 static const char app[] = "Echo";
00050 
00051 static int echo_exec(struct ast_channel *chan, const char *data)
00052 {
00053    int res = -1;
00054    format_t format;
00055 
00056    format = ast_best_codec(chan->nativeformats);
00057    ast_set_write_format(chan, format);
00058    ast_set_read_format(chan, format);
00059 
00060    while (ast_waitfor(chan, -1) > -1) {
00061       struct ast_frame *f = ast_read(chan);
00062       if (!f) {
00063          break;
00064       }
00065       f->delivery.tv_sec = 0;
00066       f->delivery.tv_usec = 0;
00067       if (ast_write(chan, f)) {
00068          ast_frfree(f);
00069          goto end;
00070       }
00071       if ((f->frametype == AST_FRAME_DTMF) && (f->subclass.integer == '#')) {
00072          res = 0;
00073          ast_frfree(f);
00074          goto end;
00075       }
00076       ast_frfree(f);
00077    }
00078 end:
00079    return res;
00080 }
00081 
00082 static int unload_module(void)
00083 {
00084    return ast_unregister_application(app);
00085 }
00086 
00087 static int load_module(void)
00088 {
00089    return ast_register_application_xml(app, echo_exec);
00090 }
00091 
00092 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Simple Echo Application");

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