Mon Mar 31 07:38:02 2008

Asterisk developer's documentation


func_rand.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 2006, Digium, Inc.
00005  * Copyright (C) 2006, Claude Patry
00006  *
00007  * See http://www.asterisk.org for more information about
00008  * the Asterisk project. Please do not directly contact
00009  * any of the maintainers of this project for assistance;
00010  * the project provides a web site, mailing lists and IRC
00011  * channels for your use.
00012  *
00013  * This program is free software, distributed under the terms of
00014  * the GNU General Public License Version 2. See the LICENSE file
00015  * at the top of the source tree.
00016  */
00017 
00018 /*! \file
00019  *
00020  * \brief Generate Random Number
00021  * 
00022  * \author Claude Patry <cpatry@gmail.com>
00023  * \author Tilghman Lesher ( http://asterisk.drunkcoder.com/ )
00024  * \ingroup functions
00025  */
00026 
00027 #include "asterisk.h"
00028 
00029 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
00030 
00031 #include <stdlib.h>
00032 #include <string.h>
00033 #include <stdio.h>
00034 #include <sys/types.h>
00035 
00036 #include "asterisk/module.h"
00037 #include "asterisk/channel.h"
00038 #include "asterisk/pbx.h"
00039 #include "asterisk/logger.h"
00040 #include "asterisk/utils.h"
00041 #include "asterisk/app.h"
00042 
00043 static int acf_rand_exec(struct ast_channel *chan, char *cmd,
00044           char *parse, char *buffer, size_t buflen)
00045 {
00046    struct ast_module_user *u;
00047    int min_int, response_int, max_int;
00048    AST_DECLARE_APP_ARGS(args,
00049               AST_APP_ARG(min);
00050               AST_APP_ARG(max);
00051    );
00052 
00053    u = ast_module_user_add(chan);
00054 
00055    AST_STANDARD_APP_ARGS(args, parse);
00056 
00057    if (ast_strlen_zero(args.min) || sscanf(args.min, "%d", &min_int) != 1)
00058       min_int = 0;
00059 
00060    if (ast_strlen_zero(args.max) || sscanf(args.max, "%d", &max_int) != 1)
00061       max_int = RAND_MAX;
00062 
00063    if (max_int < min_int) {
00064       int tmp = max_int;
00065 
00066       max_int = min_int;
00067       min_int = tmp;
00068       ast_log(LOG_DEBUG, "max<min\n");
00069    }
00070 
00071    response_int = min_int + (ast_random() % (max_int - min_int + 1));
00072    ast_log(LOG_DEBUG, "%d was the lucky number in range [%d,%d]\n",
00073       response_int, min_int, max_int);
00074    snprintf(buffer, buflen, "%d", response_int);
00075 
00076    ast_module_user_remove(u);
00077 
00078    return 0;
00079 }
00080 
00081 static struct ast_custom_function acf_rand = {
00082    .name = "RAND",
00083    .synopsis = "Choose a random number in a range",
00084    .syntax = "RAND([min][|max])",
00085    .desc =
00086       "Choose a random number between min and max.  Min defaults to 0, if not\n"
00087       "specified, while max defaults to RAND_MAX (2147483647 on many systems).\n"
00088       "  Example:  Set(junky=${RAND(1|8)}); \n"
00089       "  Sets junky to a random number between 1 and 8, inclusive.\n",
00090    .read = acf_rand_exec,
00091 };
00092 
00093 static int unload_module(void)
00094 {
00095    ast_custom_function_unregister(&acf_rand);
00096 
00097    return 0;
00098 }
00099 
00100 static int load_module(void)
00101 {
00102    return ast_custom_function_register(&acf_rand);
00103 }
00104 
00105 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Random number dialplan function");

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