482 lines
12 KiB
PHP
482 lines
12 KiB
PHP
<?php
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/**
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* Crypt_RSA allows to do following operations:
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* - key pair generation
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* - encryption and decryption
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* - signing and sign validation
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*
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* PHP versions 4 and 5
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*
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* LICENSE: This source file is subject to version 3.0 of the PHP license
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* that is available through the world-wide-web at the following URI:
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* http://www.php.net/license/3_0.txt. If you did not receive a copy of
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* the PHP License and are unable to obtain it through the web, please
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* send a note to license@php.net so we can mail you a copy immediately.
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*
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* @category Encryption
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* @package Crypt_RSA
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* @author Alexander Valyalkin <valyala@gmail.com>
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* @copyright 2006 Alexander Valyalkin
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* @license http://www.php.net/license/3_0.txt PHP License 3.0
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* @version 1.2.0b
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* @link http://pear.php.net/package/Crypt_RSA
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*/
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/**
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* Crypt_RSA_Math_BCMath class.
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*
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* Provides set of math functions, which are used by Crypt_RSA package
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* This class is a wrapper for PHP BCMath extension.
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* See http://php.net/manual/en/ref.bc.php for details.
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*
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* @category Encryption
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* @package Crypt_RSA
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* @author Alexander Valyalkin <valyala@gmail.com>
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* @copyright 2005, 2006 Alexander Valyalkin
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* @license http://www.php.net/license/3_0.txt PHP License 3.0
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* @link http://pear.php.net/package/Crypt_RSA
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* @version @package_version@
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* @access public
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*/
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class Crypt_RSA_Math_BCMath
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{
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/**
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* error description
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*
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* @var string
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* @access public
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*/
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var $errstr = '';
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/**
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* Performs Miller-Rabin primality test for number $num
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* with base $base. Returns true, if $num is strong pseudoprime
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* by base $base. Else returns false.
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*
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* @param string $num
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* @param string $base
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* @return bool
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* @access private
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*/
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function _millerTest($num, $base)
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{
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if (!bccomp($num, '1')) {
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// 1 is not prime ;)
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return false;
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}
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$tmp = bcsub($num, '1');
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$zero_bits = 0;
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while (!bccomp(bcmod($tmp, '2'), '0')) {
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$zero_bits++;
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$tmp = bcdiv($tmp, '2');
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}
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$tmp = $this->powmod($base, $tmp, $num);
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if (!bccomp($tmp, '1')) {
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// $num is probably prime
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return true;
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}
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while ($zero_bits--) {
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if (!bccomp(bcadd($tmp, '1'), $num)) {
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// $num is probably prime
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return true;
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}
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$tmp = $this->powmod($tmp, '2', $num);
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}
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// $num is composite
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return false;
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}
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/**
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* Crypt_RSA_Math_BCMath constructor.
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* Checks an existance of PHP BCMath extension.
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* On failure saves error description in $this->errstr
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*
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* @access public
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*/
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function Crypt_RSA_Math_BCMath()
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{
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if (!extension_loaded('bcmath')) {
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if (!@dl('bcmath.' . PHP_SHLIB_SUFFIX) && !@dl('php_bcmath.' . PHP_SHLIB_SUFFIX)) {
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// cannot load BCMath extension. Set error string
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$this->errstr = 'Crypt_RSA package requires the BCMath extension. See http://php.net/manual/en/ref.bc.php for details';
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return;
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}
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}
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}
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/**
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* Transforms binary representation of large integer into its native form.
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*
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* Example of transformation:
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* $str = "\x12\x34\x56\x78\x90";
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* $num = 0x9078563412;
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*
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* @param string $str
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* @return string
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* @access public
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*/
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function bin2int($str)
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{
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$result = '0';
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$n = strlen($str);
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do {
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$result = bcadd(bcmul($result, '256'), ord($str{--$n}));
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} while ($n > 0);
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return $result;
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}
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/**
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* Transforms large integer into binary representation.
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*
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* Example of transformation:
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* $num = 0x9078563412;
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* $str = "\x12\x34\x56\x78\x90";
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*
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* @param string $num
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* @return string
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* @access public
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*/
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function int2bin($num)
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{
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$result = '';
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do {
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$result .= chr(bcmod($num, '256'));
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$num = bcdiv($num, '256');
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} while (bccomp($num, '0'));
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return $result;
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}
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/**
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* Calculates pow($num, $pow) (mod $mod)
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*
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* @param string $num
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* @param string $pow
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* @param string $mod
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* @return string
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* @access public
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*/
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function powmod($num, $pow, $mod)
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{
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if (function_exists('bcpowmod')) {
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// bcpowmod is only available under PHP5
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return bcpowmod($num, $pow, $mod);
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}
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// emulate bcpowmod
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$result = '1';
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do {
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if (!bccomp(bcmod($pow, '2'), '1')) {
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$result = bcmod(bcmul($result, $num), $mod);
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}
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$num = bcmod(bcpow($num, '2'), $mod);
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$pow = bcdiv($pow, '2');
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} while (bccomp($pow, '0'));
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return $result;
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}
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/**
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* Calculates $num1 * $num2
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*
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* @param string $num1
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* @param string $num2
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* @return string
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* @access public
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*/
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function mul($num1, $num2)
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{
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return bcmul($num1, $num2);
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}
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/**
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* Calculates $num1 % $num2
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*
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* @param string $num1
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* @param string $num2
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* @return string
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* @access public
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*/
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function mod($num1, $num2)
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{
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return bcmod($num1, $num2);
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}
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/**
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* Compares abs($num1) to abs($num2).
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* Returns:
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* -1, if abs($num1) < abs($num2)
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* 0, if abs($num1) == abs($num2)
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* 1, if abs($num1) > abs($num2)
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*
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* @param string $num1
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* @param string $num2
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* @return int
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* @access public
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*/
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function cmpAbs($num1, $num2)
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{
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return bccomp($num1, $num2);
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}
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/**
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* Tests $num on primality. Returns true, if $num is strong pseudoprime.
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* Else returns false.
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*
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* @param string $num
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* @return bool
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* @access private
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*/
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function isPrime($num)
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{
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static $primes = null;
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static $primes_cnt = 0;
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if (is_null($primes)) {
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// generate all primes up to 10000
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$primes = array();
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for ($i = 0; $i < 10000; $i++) {
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$primes[] = $i;
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}
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$primes[0] = $primes[1] = 0;
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for ($i = 2; $i < 100; $i++) {
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while (!$primes[$i]) {
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$i++;
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}
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$j = $i;
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for ($j += $i; $j < 10000; $j += $i) {
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$primes[$j] = 0;
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}
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}
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$j = 0;
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for ($i = 0; $i < 10000; $i++) {
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if ($primes[$i]) {
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$primes[$j++] = $primes[$i];
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}
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}
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$primes_cnt = $j;
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}
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// try to divide number by small primes
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for ($i = 0; $i < $primes_cnt; $i++) {
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if (bccomp($num, $primes[$i]) <= 0) {
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// number is prime
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return true;
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}
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if (!bccomp(bcmod($num, $primes[$i]), '0')) {
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// number divides by $primes[$i]
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return false;
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}
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}
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/*
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try Miller-Rabin's probable-primality test for first
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7 primes as bases
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*/
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for ($i = 0; $i < 7; $i++) {
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if (!$this->_millerTest($num, $primes[$i])) {
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// $num is composite
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return false;
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}
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}
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// $num is strong pseudoprime
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return true;
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}
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/**
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* Generates prime number with length $bits_cnt
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* using $random_generator as random generator function.
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*
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* @param int $bits_cnt
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* @param string $rnd_generator
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* @access public
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*/
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function getPrime($bits_cnt, $random_generator)
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{
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$bytes_n = intval($bits_cnt / 8);
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$bits_n = $bits_cnt % 8;
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do {
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$str = '';
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for ($i = 0; $i < $bytes_n; $i++) {
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$str .= chr(call_user_func($random_generator) & 0xff);
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}
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$n = call_user_func($random_generator) & 0xff;
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$n |= 0x80;
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$n >>= 8 - $bits_n;
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$str .= chr($n);
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$num = $this->bin2int($str);
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// search for the next closest prime number after [$num]
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if (!bccomp(bcmod($num, '2'), '0')) {
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$num = bcadd($num, '1');
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}
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while (!$this->isPrime($num)) {
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$num = bcadd($num, '2');
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}
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} while ($this->bitLen($num) != $bits_cnt);
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return $num;
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}
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/**
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* Calculates $num - 1
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*
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* @param string $num
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* @return string
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* @access public
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*/
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function dec($num)
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{
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return bcsub($num, '1');
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}
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/**
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* Returns true, if $num is equal to one. Else returns false
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*
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* @param string $num
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* @return bool
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* @access public
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*/
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function isOne($num)
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{
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return !bccomp($num, '1');
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}
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/**
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* Finds greatest common divider (GCD) of $num1 and $num2
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*
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* @param string $num1
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* @param string $num2
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* @return string
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* @access public
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*/
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function GCD($num1, $num2)
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{
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do {
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$tmp = bcmod($num1, $num2);
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$num1 = $num2;
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$num2 = $tmp;
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} while (bccomp($num2, '0'));
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return $num1;
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}
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/**
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* Finds inverse number $inv for $num by modulus $mod, such as:
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* $inv * $num = 1 (mod $mod)
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*
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* @param string $num
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* @param string $mod
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* @return string
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* @access public
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*/
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function invmod($num, $mod)
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{
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$x = '1';
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$y = '0';
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$num1 = $mod;
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do {
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$tmp = bcmod($num, $num1);
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$q = bcdiv($num, $num1);
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$num = $num1;
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$num1 = $tmp;
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$tmp = bcsub($x, bcmul($y, $q));
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$x = $y;
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$y = $tmp;
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} while (bccomp($num1, '0'));
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if (bccomp($x, '0') < 0) {
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$x = bcadd($x, $mod);
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}
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return $x;
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}
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/**
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* Returns bit length of number $num
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*
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* @param string $num
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* @return int
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* @access public
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*/
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function bitLen($num)
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{
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$tmp = $this->int2bin($num);
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$bit_len = strlen($tmp) * 8;
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$tmp = ord($tmp{strlen($tmp) - 1});
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if (!$tmp) {
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$bit_len -= 8;
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}
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else {
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while (!($tmp & 0x80)) {
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$bit_len--;
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$tmp <<= 1;
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}
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}
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return $bit_len;
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}
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/**
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* Calculates bitwise or of $num1 and $num2,
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* starting from bit $start_pos for number $num1
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*
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* @param string $num1
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* @param string $num2
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* @param int $start_pos
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* @return string
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* @access public
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*/
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function bitOr($num1, $num2, $start_pos)
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{
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$start_byte = intval($start_pos / 8);
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$start_bit = $start_pos % 8;
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$tmp1 = $this->int2bin($num1);
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$num2 = bcmul($num2, 1 << $start_bit);
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$tmp2 = $this->int2bin($num2);
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if ($start_byte < strlen($tmp1)) {
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$tmp2 |= substr($tmp1, $start_byte);
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$tmp1 = substr($tmp1, 0, $start_byte) . $tmp2;
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}
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else {
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$tmp1 = str_pad($tmp1, $start_byte, "\0") . $tmp2;
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}
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return $this->bin2int($tmp1);
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}
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/**
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* Returns part of number $num, starting at bit
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* position $start with length $length
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*
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* @param string $num
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* @param int start
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* @param int length
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* @return string
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* @access public
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*/
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function subint($num, $start, $length)
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{
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$start_byte = intval($start / 8);
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$start_bit = $start % 8;
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$byte_length = intval($length / 8);
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$bit_length = $length % 8;
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if ($bit_length) {
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$byte_length++;
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}
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$num = bcdiv($num, 1 << $start_bit);
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$tmp = substr($this->int2bin($num), $start_byte, $byte_length);
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$tmp = str_pad($tmp, $byte_length, "\0");
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$tmp = substr_replace($tmp, $tmp{$byte_length - 1} & chr(0xff >> (8 - $bit_length)), $byte_length - 1, 1);
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return $this->bin2int($tmp);
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}
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/**
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* Returns name of current wrapper
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*
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* @return string name of current wrapper
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* @access public
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*/
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function getWrapperName()
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{
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return 'BCMath';
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}
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}
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?>
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