Mon Sep 18 09:12:40 2006

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  * \ingroup applications
00024  */
00025 
00026 #include <stdlib.h>
00027 #include <stdio.h>
00028 #include <unistd.h>
00029 #include <string.h>
00030 
00031 #include "asterisk.h"
00032 
00033 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 7221 $")
00034 
00035 #include "asterisk/lock.h"
00036 #include "asterisk/file.h"
00037 #include "asterisk/logger.h"
00038 #include "asterisk/channel.h"
00039 #include "asterisk/pbx.h"
00040 #include "asterisk/module.h"
00041 
00042 static char *tdesc = "Simple Echo Application";
00043 
00044 static char *app = "Echo";
00045 
00046 static char *synopsis = "Echo audio read back to the user";
00047 
00048 static char *descrip = 
00049 "  Echo():  Echo audio read from channel back to the channel. \n"
00050 "User can exit the application by either pressing the '#' key, \n"
00051 "or hanging up.\n";
00052 
00053 STANDARD_LOCAL_USER;
00054 
00055 LOCAL_USER_DECL;
00056 
00057 static int echo_exec(struct ast_channel *chan, void *data)
00058 {
00059    int res=-1;
00060    struct localuser *u;
00061    struct ast_frame *f;
00062    LOCAL_USER_ADD(u);
00063    ast_set_write_format(chan, ast_best_codec(chan->nativeformats));
00064    ast_set_read_format(chan, ast_best_codec(chan->nativeformats));
00065    /* Do our thing here */
00066    while(ast_waitfor(chan, -1) > -1) {
00067       f = ast_read(chan);
00068       if (!f)
00069          break;
00070       f->delivery.tv_sec = 0;
00071       f->delivery.tv_usec = 0;
00072       if (f->frametype == AST_FRAME_VOICE) {
00073          if (ast_write(chan, f)) 
00074             break;
00075       } else if (f->frametype == AST_FRAME_VIDEO) {
00076          if (ast_write(chan, f)) 
00077             break;
00078       } else if (f->frametype == AST_FRAME_DTMF) {
00079          if (f->subclass == '#') {
00080             res = 0;
00081             break;
00082          } else
00083             if (ast_write(chan, f))
00084                break;
00085       }
00086       ast_frfree(f);
00087    }
00088    LOCAL_USER_REMOVE(u);
00089    return res;
00090 }
00091 
00092 int unload_module(void)
00093 {
00094    int res;
00095 
00096    res = ast_unregister_application(app);
00097 
00098    STANDARD_HANGUP_LOCALUSERS;
00099 
00100    return res;
00101 }
00102 
00103 int load_module(void)
00104 {
00105    return ast_register_application(app, echo_exec, synopsis, descrip);
00106 }
00107 
00108 char *description(void)
00109 {
00110    return tdesc;
00111 }
00112 
00113 int usecount(void)
00114 {
00115    int res;
00116    STANDARD_USECOUNT(res);
00117    return res;
00118 }
00119 
00120 char *key()
00121 {
00122    return ASTERISK_GPL_KEY;
00123 }

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