Asterisk - The Open Source Telephony Project  21.4.1
func_rand.c
Go to the documentation of this file.
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2006, Digium, Inc.
5  * Copyright (C) 2006, Claude Patry
6  *
7  * See http://www.asterisk.org for more information about
8  * the Asterisk project. Please do not directly contact
9  * any of the maintainers of this project for assistance;
10  * the project provides a web site, mailing lists and IRC
11  * channels for your use.
12  *
13  * This program is free software, distributed under the terms of
14  * the GNU General Public License Version 2. See the LICENSE file
15  * at the top of the source tree.
16  */
17 
18 /*! \file
19  *
20  * \brief Generate Random Number
21  *
22  * \author Claude Patry <cpatry@gmail.com>
23  * \author Tilghman Lesher ( http://asterisk.drunkcoder.com/ )
24  * \ingroup functions
25  */
26 
27 /*** MODULEINFO
28  <support_level>core</support_level>
29  ***/
30 
31 #include "asterisk.h"
32 
33 #include "asterisk/module.h"
34 #include "asterisk/channel.h"
35 #include "asterisk/pbx.h"
36 #include "asterisk/utils.h"
37 #include "asterisk/app.h"
38 
39 /*** DOCUMENTATION
40  <function name="RAND" language="en_US">
41  <synopsis>
42  Choose a random number in a range.
43  </synopsis>
44  <syntax>
45  <parameter name="min" />
46  <parameter name="max" />
47  </syntax>
48  <description>
49  <para>Choose a random number between <replaceable>min</replaceable> and <replaceable>max</replaceable>.
50  <replaceable>min</replaceable> defaults to <literal>0</literal>, if not specified, while <replaceable>max</replaceable> defaults
51  to <literal>RAND_MAX</literal> (2147483647 on many systems).</para>
52  <example title="Set random number between 1 and 8, inclusive">
53  exten => s,1,Set(junky=${RAND(1,8)})
54  </example>
55  </description>
56  </function>
57  ***/
58 static int acf_rand_exec(struct ast_channel *chan, const char *cmd,
59  char *parse, char *buffer, size_t buflen)
60 {
61  int min_int, response_int, max_int;
63  AST_APP_ARG(min);
64  AST_APP_ARG(max);
65  );
66 
67  AST_STANDARD_APP_ARGS(args, parse);
68 
69  if (ast_strlen_zero(args.min) || sscanf(args.min, "%30d", &min_int) != 1)
70  min_int = 0;
71 
72  if (ast_strlen_zero(args.max) || sscanf(args.max, "%30d", &max_int) != 1)
73  max_int = RAND_MAX;
74 
75  if (max_int < min_int) {
76  int tmp = max_int;
77 
78  max_int = min_int;
79  min_int = tmp;
80  ast_debug(1, "max<min\n");
81  }
82 
83  response_int = min_int + (ast_random() % (max_int - min_int + 1));
84  ast_debug(1, "%d was the lucky number in range [%d,%d]\n", response_int, min_int, max_int);
85  snprintf(buffer, buflen, "%d", response_int);
86 
87  return 0;
88 }
89 
90 static struct ast_custom_function acf_rand = {
91  .name = "RAND",
92  .read = acf_rand_exec,
93  .read_max = 12,
94 };
95 
96 static int unload_module(void)
97 {
99 
100  return 0;
101 }
102 
103 static int load_module(void)
104 {
105  return ast_custom_function_register(&acf_rand);
106 }
107 
108 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Random number dialplan function");
const char * name
Definition: pbx.h:119
Main Channel structure associated with a channel.
Asterisk main include file. File version handling, generic pbx functions.
#define AST_STANDARD_APP_ARGS(args, parse)
Performs the 'standard' argument separation process for an application.
int ast_custom_function_unregister(struct ast_custom_function *acf)
Unregister a custom function.
Utility functions.
General Asterisk PBX channel definitions.
Data structure associated with a custom dialplan function.
Definition: pbx.h:118
#define ast_debug(level,...)
Log a DEBUG message.
Core PBX routines and definitions.
#define ASTERISK_GPL_KEY
The text the key() function should return.
Definition: module.h:46
Asterisk module definitions.
#define AST_DECLARE_APP_ARGS(name, arglist)
Declare a structure to hold an application's arguments.
Application convenience functions, designed to give consistent look and feel to Asterisk apps...
#define ast_custom_function_register(acf)
Register a custom function.
Definition: pbx.h:1558
#define AST_APP_ARG(name)
Define an application argument.