Fri Jul 24 00:40:56 2009

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: 89512 $")
00030 
00031 #include "asterisk/module.h"
00032 #include "asterisk/channel.h"
00033 #include "asterisk/pbx.h"
00034 #include "asterisk/utils.h"
00035 #include "asterisk/app.h"
00036 
00037 static int acf_rand_exec(struct ast_channel *chan, const char *cmd,
00038           char *parse, char *buffer, size_t buflen)
00039 {
00040    int min_int, response_int, max_int;
00041    AST_DECLARE_APP_ARGS(args,
00042               AST_APP_ARG(min);
00043               AST_APP_ARG(max);
00044    );
00045 
00046    AST_STANDARD_APP_ARGS(args, parse);
00047 
00048    if (ast_strlen_zero(args.min) || sscanf(args.min, "%d", &min_int) != 1)
00049       min_int = 0;
00050 
00051    if (ast_strlen_zero(args.max) || sscanf(args.max, "%d", &max_int) != 1)
00052       max_int = RAND_MAX;
00053 
00054    if (max_int < min_int) {
00055       int tmp = max_int;
00056 
00057       max_int = min_int;
00058       min_int = tmp;
00059       ast_debug(1, "max<min\n");
00060    }
00061 
00062    response_int = min_int + (ast_random() % (max_int - min_int + 1));
00063    ast_debug(1, "%d was the lucky number in range [%d,%d]\n", response_int, min_int, max_int);
00064    snprintf(buffer, buflen, "%d", response_int);
00065 
00066    return 0;
00067 }
00068 
00069 static struct ast_custom_function acf_rand = {
00070    .name = "RAND",
00071    .synopsis = "Choose a random number in a range",
00072    .syntax = "RAND([min][,max])",
00073    .desc =
00074       "Choose a random number between min and max.  Min defaults to 0, if not\n"
00075       "specified, while max defaults to RAND_MAX (2147483647 on many systems).\n"
00076       "  Example:  Set(junky=${RAND(1,8)}); \n"
00077       "  Sets junky to a random number between 1 and 8, inclusive.\n",
00078    .read = acf_rand_exec,
00079 };
00080 
00081 static int unload_module(void)
00082 {
00083    ast_custom_function_unregister(&acf_rand);
00084 
00085    return 0;
00086 }
00087 
00088 static int load_module(void)
00089 {
00090    return ast_custom_function_register(&acf_rand);
00091 }
00092 
00093 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Random number dialplan function");

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