Sat Mar 24 22:55:12 2007

Asterisk developer's documentation


app_random.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (c) 2003 - 2005 Tilghman Lesher.  All rights reserved.
00005  *
00006  * Tilghman Lesher <asterisk__app_random__200508@the-tilghman.com>
00007  *
00008  * This code is released by the author with no restrictions on usage or distribution.
00009  *
00010  * See http://www.asterisk.org for more information about
00011  * the Asterisk project. Please do not directly contact
00012  * any of the maintainers of this project for assistance;
00013  * the project provides a web site, mailing lists and IRC
00014  * channels for your use.
00015  *
00016  */
00017 
00018 /*! \file
00019  *
00020  * \brief Random application
00021  *
00022  * \author Tilghman Lesher <asterisk__app_random__200508@the-tilghman.com>
00023  * \ingroup applications
00024  */
00025 
00026 #include <stdio.h>
00027 #include <stdlib.h>
00028 #include <unistd.h>
00029 #include <string.h>
00030 
00031 #include "asterisk.h"
00032 
00033 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 40821 $")
00034 
00035 #include "asterisk/file.h"
00036 #include "asterisk/logger.h"
00037 #include "asterisk/options.h"
00038 #include "asterisk/channel.h"
00039 #include "asterisk/pbx.h"
00040 #include "asterisk/module.h"
00041 
00042 static char *tdesc = "Random goto";
00043 
00044 static char *app_random = "Random";
00045 
00046 static char *random_synopsis = "Conditionally branches, based upon a probability";
00047 
00048 static char *random_descrip =
00049 "Random([probability]:[[context|]extension|]priority)\n"
00050 "  probability := INTEGER in the range 1 to 100\n";
00051 
00052 STANDARD_LOCAL_USER;
00053 
00054 LOCAL_USER_DECL;
00055 
00056 static char random_state[256];
00057 
00058 static int random_exec(struct ast_channel *chan, void *data)
00059 {
00060    int res=0;
00061    struct localuser *u;
00062 
00063    char *s;
00064    char *prob;
00065    int probint;
00066    
00067    if (ast_strlen_zero(data)) {
00068       ast_log(LOG_WARNING, "Random requires an argument ([probability]:[[context|]extension|]priority)\n");
00069       return -1;
00070    }
00071    
00072    LOCAL_USER_ADD(u);
00073 
00074    s = ast_strdupa(data);
00075    if (!s) {
00076       ast_log(LOG_ERROR, "Out of memory!\n");
00077       LOCAL_USER_REMOVE(u);
00078       return -1;
00079    }
00080 
00081    prob = strsep(&s,":");
00082    if ((!prob) || (sscanf(prob, "%d", &probint) != 1))
00083       probint = 0;
00084 
00085    if ((random() % 100) + probint >= 100) {
00086       res = ast_parseable_goto(chan, s);
00087       if (option_verbose > 2)
00088          ast_verbose( VERBOSE_PREFIX_3 "Random branches to (%s,%s,%d)\n",
00089             chan->context,chan->exten, chan->priority+1);
00090    }
00091    LOCAL_USER_REMOVE(u);
00092    return res;
00093 }
00094 
00095 int unload_module(void)
00096 {
00097    int res;
00098    
00099    res = ast_unregister_application(app_random);
00100    
00101    STANDARD_HANGUP_LOCALUSERS;
00102 
00103    return res; 
00104 }
00105 
00106 int load_module(void)
00107 {
00108    initstate((getppid() * 65535 + getpid()) % RAND_MAX, random_state, 256);
00109    return ast_register_application(app_random, random_exec, random_synopsis, random_descrip);
00110 }
00111 
00112 char *description(void)
00113 {
00114    return tdesc;
00115 }
00116 
00117 int usecount(void)
00118 {
00119    /* Don't allow unload, since rand(3) depends upon this module being here. */
00120    return 1;
00121 }
00122 
00123 char *key()
00124 {
00125    return ASTERISK_GPL_KEY;
00126 }

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