Viewing file:  bcinvert.php (2.6 KB) -rw-rw-rw-
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<?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: bcinvert.php,v 1.2 2005/11/22 20:24:45 aidan Exp $
/**
* Replace bcinvert()
*
* @category PHP
* @package PHP_Compat
* @link http://php.net/function.bcinvert
* @author Sara Golemon <pollita@php.net>
* @version $Revision: 1.2 $
* @since PHP 5.2.0
* @require PHP 4.0.4 (call_user_func_array)
*/
if (!function_exists('bcinvert')) {
function bcinvert($a, $n)
{
// Sanity check
if (!is_scalar($a)) {
user_error('bcinvert() expects parameter 1 to be string, ' .
gettype($a) . ' given', E_USER_WARNING);
return false;
}
if (!is_scalar($n)) {
user_error('bcinvert() expects parameter 2 to be string, ' .
gettype($n) . ' given', E_USER_WARNING);
return false;
}
$u1 = $v2 = '1';
$u2 = $v1 = '0';
$u3 = $n;
$v3 = $a;
while (bccomp($v3, '0')) {
$q0 = bcdiv($u3, $v3);
$t1 = bcsub($u1, bcmul($q0, $v1));
$t2 = bcsub($u2, bcmul($q0, $v2));
$t3 = bcsub($u3, bcmul($q0, $v3));
$u1 = $v1;
$u2 = $v2;
$u3 = $v3;
$v1 = $t1;
$v2 = $t2;
$v3 = $t3;
}
if (bccomp($u2, '0') < 0) {
return bcadd($u2, $n);
} else {
return bcmod($u2, $n);
}
}
}
?>
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