76 lines
2.5 KiB
PHP
76 lines
2.5 KiB
PHP
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<?php
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// +----------------------------------------------------------------------+
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// | PHP Version 4 |
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// +----------------------------------------------------------------------+
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// | Copyright (c) 1997-2004 The PHP Group |
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// +----------------------------------------------------------------------+
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// | This source file is subject to version 3.0 of the PHP license, |
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// | that is bundled with this package in the file LICENSE, and is |
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// | available at through the world-wide-web at |
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// | http://www.php.net/license/3_0.txt. |
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// | If you did not receive a copy of the PHP license and are unable to |
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// | obtain it through the world-wide-web, please send a note to |
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// | license@php.net so we can mail you a copy immediately. |
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// +----------------------------------------------------------------------+
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// | Authors: Aidan Lister <aidan@php.net> |
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// +----------------------------------------------------------------------+
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//
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// $Id: bcinvert.php,v 1.2 2005/11/22 20:24:45 aidan Exp $
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/**
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* Replace bcinvert()
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*
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* @category PHP
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* @package PHP_Compat
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* @link http://php.net/function.bcinvert
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* @author Sara Golemon <pollita@php.net>
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* @version $Revision: 1.2 $
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* @since PHP 5.2.0
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* @require PHP 4.0.4 (call_user_func_array)
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*/
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if (!function_exists('bcinvert')) {
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function bcinvert($a, $n)
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{
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// Sanity check
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if (!is_scalar($a)) {
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user_error('bcinvert() expects parameter 1 to be string, ' .
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gettype($a) . ' given', E_USER_WARNING);
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return false;
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}
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if (!is_scalar($n)) {
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user_error('bcinvert() expects parameter 2 to be string, ' .
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gettype($n) . ' given', E_USER_WARNING);
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return false;
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}
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$u1 = $v2 = '1';
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$u2 = $v1 = '0';
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$u3 = $n;
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$v3 = $a;
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while (bccomp($v3, '0')) {
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$q0 = bcdiv($u3, $v3);
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$t1 = bcsub($u1, bcmul($q0, $v1));
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$t2 = bcsub($u2, bcmul($q0, $v2));
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$t3 = bcsub($u3, bcmul($q0, $v3));
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$u1 = $v1;
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$u2 = $v2;
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$u3 = $v3;
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$v1 = $t1;
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$v2 = $t2;
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$v3 = $t3;
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}
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if (bccomp($u2, '0') < 0) {
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return bcadd($u2, $n);
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} else {
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return bcmod($u2, $n);
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}
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}
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}
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?>
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