source: branches/version-2_5-dev/data/module/Compat/Compat/Function/bcpowmod.php @ 20764

Revision 20764, 2.7 KB checked in by nanasess, 13 years ago (diff)

#601 (コピーライトの更新)

  • Property svn:eol-style set to LF
  • Property svn:mime-type set to text/x-httpd-php; charset=UTF-8
Line 
1<?php
2// +----------------------------------------------------------------------+
3// | PHP Version 4                                                        |
4// +----------------------------------------------------------------------+
5// | Copyright (c) 1997-2004 The PHP Group                                |
6// +----------------------------------------------------------------------+
7// | This source file is subject to version 3.0 of the PHP license,       |
8// | that is bundled with this package in the file LICENSE, and is        |
9// | available at through the world-wide-web at                           |
10// | http://www.php.net/license/3_0.txt.                                  |
11// | If you did not receive a copy of the PHP license and are unable to   |
12// | obtain it through the world-wide-web, please send a note to          |
13// | license@php.net so we can mail you a copy immediately.               |
14// +----------------------------------------------------------------------+
15// | Authors: Aidan Lister <aidan@php.net>                                |
16// +----------------------------------------------------------------------+
17//
18// $Id: bcpowmod.php,v 1.2 2005/11/22 20:24:45 aidan Exp $
19
20
21/**
22 * Replace bcpowmod()
23 *
24 * @category    PHP
25 * @package     PHP_Compat
26 * @link        http://php.net/function.bcpowmod
27 * @author      Sara Golemon <pollita@php.net>
28 * @version     $Revision: 1.2 $
29 * @since       PHP 5.0.0
30 * @require     PHP 4.0.0 (user_error)
31 */
32if (!function_exists('bcpowmod')) {
33    function bcpowmod($x, $y, $modulus, $scale)
34    {
35        // Sanity check
36        if (!is_scalar($x)) {
37            user_error('bcpowmod() expects parameter 1 to be string, ' .
38                gettype($x) . ' given', E_USER_WARNING);
39            return false;
40        }
41
42        if (!is_scalar($y)) {
43            user_error('bcpowmod() expects parameter 2 to be string, ' .
44                gettype($y) . ' given', E_USER_WARNING);
45            return false;
46        }
47
48        if (!is_scalar($modulus)) {
49            user_error('bcpowmod() expects parameter 3 to be string, ' .
50                gettype($modulus) . ' given', E_USER_WARNING);
51            return false;
52        }
53
54        if (!is_scalar($scale)) {
55            user_error('bcpowmod() expects parameter 4 to be integer, ' .
56                gettype($scale) . ' given', E_USER_WARNING);
57            return false;
58        }
59
60        $t = '1';
61        while (bccomp($y, '0')) {
62            if (bccomp(bcmod($y, '2'), '0')) {
63                $t = bcmod(bcmul($t, $x), $modulus);
64                $y = bcsub($y, '1');
65            }
66
67            $x = bcmod(bcmul($x, $x), $modulus);
68            $y = bcdiv($y, '2');
69        }
70
71        return $t;
72    }
73}
74
75?>
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