Wed Aug 18 22:33:41 2010

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: 249949 $")
00031 
00032 #include "asterisk/file.h"
00033 #include "asterisk/module.h"
00034 #include "asterisk/channel.h"
00035 
00036 static char *app = "Echo";
00037 
00038 static char *synopsis = "Echo audio, video, or DTMF back to the calling party";
00039 
00040 static char *descrip =
00041 "  Echo(): This application will echo any audio, video, or DTMF frames read from\n"
00042 "the calling channel back to itself. If the DTMF digit '#' is received, the\n"
00043 "application will exit.\n";
00044 
00045 
00046 static int echo_exec(struct ast_channel *chan, void *data)
00047 {
00048    int res = -1;
00049    int format;
00050 
00051    format = ast_best_codec(chan->nativeformats);
00052    ast_set_write_format(chan, format);
00053    ast_set_read_format(chan, format);
00054 
00055    while (ast_waitfor(chan, -1) > -1) {
00056       struct ast_frame *f = ast_read(chan);
00057       if (!f) {
00058          break;
00059       }
00060       f->delivery.tv_sec = 0;
00061       f->delivery.tv_usec = 0;
00062       if (ast_write(chan, f)) {
00063          ast_frfree(f);
00064          goto end;
00065       }
00066       if ((f->frametype == AST_FRAME_DTMF) && (f->subclass == '#')) {
00067          res = 0;
00068          ast_frfree(f);
00069          goto end;
00070       }
00071       ast_frfree(f);
00072    }
00073 end:
00074    return res;
00075 }
00076 
00077 static int unload_module(void)
00078 {
00079    return ast_unregister_application(app);
00080 }
00081 
00082 static int load_module(void)
00083 {
00084    return ast_register_application(app, echo_exec, synopsis, descrip);
00085 }
00086 
00087 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Simple Echo Application");

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