0,0 → 1,75 |
<?php |
// +----------------------------------------------------------------------+ |
// | PHP Version 4 | |
// +----------------------------------------------------------------------+ |
// | Copyright (c) 1997-2004 The PHP Group | |
// +----------------------------------------------------------------------+ |
// | This source file is subject to version 3.0 of the PHP license, | |
// | that is bundled with this package in the file LICENSE, and is | |
// | available at through the world-wide-web at | |
// | http://www.php.net/license/3_0.txt. | |
// | If you did not receive a copy of the PHP license and are unable to | |
// | obtain it through the world-wide-web, please send a note to | |
// | license@php.net so we can mail you a copy immediately. | |
// +----------------------------------------------------------------------+ |
// | Authors: Aidan Lister <aidan@php.net> | |
// +----------------------------------------------------------------------+ |
// |
// $Id: bcpowmod.php,v 1.2 2005/11/22 20:24:45 aidan Exp $ |
|
|
/** |
* Replace bcpowmod() |
* |
* @category PHP |
* @package PHP_Compat |
* @link http://php.net/function.bcpowmod |
* @author Sara Golemon <pollita@php.net> |
* @version $Revision: 1.2 $ |
* @since PHP 5.0.0 |
* @require PHP 4.0.0 (user_error) |
*/ |
if (!function_exists('bcpowmod')) { |
function bcpowmod($x, $y, $modulus, $scale) |
{ |
// Sanity check |
if (!is_scalar($x)) { |
user_error('bcpowmod() expects parameter 1 to be string, ' . |
gettype($x) . ' given', E_USER_WARNING); |
return false; |
} |
|
if (!is_scalar($y)) { |
user_error('bcpowmod() expects parameter 2 to be string, ' . |
gettype($y) . ' given', E_USER_WARNING); |
return false; |
} |
|
if (!is_scalar($modulus)) { |
user_error('bcpowmod() expects parameter 3 to be string, ' . |
gettype($modulus) . ' given', E_USER_WARNING); |
return false; |
} |
|
if (!is_scalar($scale)) { |
user_error('bcpowmod() expects parameter 4 to be integer, ' . |
gettype($scale) . ' given', E_USER_WARNING); |
return false; |
} |
|
$t = '1'; |
while (bccomp($y, '0')) { |
if (bccomp(bcmod($y, '2'), '0')) { |
$t = bcmod(bcmul($t, $x), $modulus); |
$y = bcsub($y, '1'); |
} |
|
$x = bcmod(bcmul($x, $x), $modulus); |
$y = bcdiv($y, '2'); |
} |
|
return $t; |
} |
} |
|
?> |