3545 lines
119 KiB
PHP
3545 lines
119 KiB
PHP
<?php
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/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
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/**
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* Pure-PHP arbitrary precision integer arithmetic library.
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*
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* Supports base-2, base-10, base-16, and base-256 numbers. Uses the GMP or BCMath extensions, if available,
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* and an internal implementation, otherwise.
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*
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* PHP versions 4 and 5
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*
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* {@internal (all DocBlock comments regarding implementation - such as the one that follows - refer to the
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* {@link MATH_BIGINTEGER_MODE_INTERNAL MATH_BIGINTEGER_MODE_INTERNAL} mode)
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*
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* Math_BigInteger uses base-2**26 to perform operations such as multiplication and division and
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* base-2**52 (ie. two base 2**26 digits) to perform addition and subtraction. Because the largest possible
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* value when multiplying two base-2**26 numbers together is a base-2**52 number, double precision floating
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* point numbers - numbers that should be supported on most hardware and whose significand is 53 bits - are
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* used. As a consequence, bitwise operators such as >> and << cannot be used, nor can the modulo operator %,
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* which only supports integers. Although this fact will slow this library down, the fact that such a high
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* base is being used should more than compensate.
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*
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* When PHP version 6 is officially released, we'll be able to use 64-bit integers. This should, once again,
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* allow bitwise operators, and will increase the maximum possible base to 2**31 (or 2**62 for addition /
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* subtraction).
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*
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* Numbers are stored in {@link http://en.wikipedia.org/wiki/Endianness little endian} format. ie.
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* (new Math_BigInteger(pow(2, 26)))->value = array(0, 1)
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*
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* Useful resources are as follows:
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*
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* - {@link http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf Handbook of Applied Cryptography (HAC)}
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* - {@link http://math.libtomcrypt.com/files/tommath.pdf Multi-Precision Math (MPM)}
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* - Java's BigInteger classes. See /j2se/src/share/classes/java/math in jdk-1_5_0-src-jrl.zip
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*
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* Here's an example of how to use this library:
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* <code>
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* <?php
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* include('Math/BigInteger.php');
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*
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* $a = new Math_BigInteger(2);
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* $b = new Math_BigInteger(3);
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*
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* $c = $a->add($b);
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*
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* echo $c->toString(); // outputs 5
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* ?>
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* </code>
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*
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* LICENSE: This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*
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* @category Math
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* @package Math_BigInteger
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright MMVI Jim Wigginton
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* @license http://www.gnu.org/licenses/lgpl.txt
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* @version $Id: BigInteger.php,v 1.33 2010/03/22 22:32:03 terrafrost Exp $
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* @link http://pear.php.net/package/Math_BigInteger
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*/
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/**#@+
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* Reduction constants
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*
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* @access private
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* @see Math_BigInteger::_reduce()
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*/
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/**
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* @see Math_BigInteger::_montgomery()
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* @see Math_BigInteger::_prepMontgomery()
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*/
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define('MATH_BIGINTEGER_MONTGOMERY', 0);
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/**
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* @see Math_BigInteger::_barrett()
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*/
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define('MATH_BIGINTEGER_BARRETT', 1);
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/**
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* @see Math_BigInteger::_mod2()
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*/
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define('MATH_BIGINTEGER_POWEROF2', 2);
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/**
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* @see Math_BigInteger::_remainder()
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*/
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define('MATH_BIGINTEGER_CLASSIC', 3);
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/**
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* @see Math_BigInteger::__clone()
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*/
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define('MATH_BIGINTEGER_NONE', 4);
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/**#@-*/
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/**#@+
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* Array constants
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*
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* Rather than create a thousands and thousands of new Math_BigInteger objects in repeated function calls to add() and
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* multiply() or whatever, we'll just work directly on arrays, taking them in as parameters and returning them.
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*
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* @access private
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*/
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/**
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* $result[MATH_BIGINTEGER_VALUE] contains the value.
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*/
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define('MATH_BIGINTEGER_VALUE', 0);
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/**
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* $result[MATH_BIGINTEGER_SIGN] contains the sign.
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*/
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define('MATH_BIGINTEGER_SIGN', 1);
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/**#@-*/
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/**#@+
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* @access private
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* @see Math_BigInteger::_montgomery()
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* @see Math_BigInteger::_barrett()
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*/
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/**
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* Cache constants
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*
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* $cache[MATH_BIGINTEGER_VARIABLE] tells us whether or not the cached data is still valid.
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*/
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define('MATH_BIGINTEGER_VARIABLE', 0);
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/**
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* $cache[MATH_BIGINTEGER_DATA] contains the cached data.
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*/
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define('MATH_BIGINTEGER_DATA', 1);
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/**#@-*/
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/**#@+
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* Mode constants.
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*
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* @access private
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* @see Math_BigInteger::Math_BigInteger()
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*/
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/**
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* To use the pure-PHP implementation
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*/
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define('MATH_BIGINTEGER_MODE_INTERNAL', 1);
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/**
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* To use the BCMath library
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*
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* (if enabled; otherwise, the internal implementation will be used)
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*/
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define('MATH_BIGINTEGER_MODE_BCMATH', 2);
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/**
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* To use the GMP library
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*
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* (if present; otherwise, either the BCMath or the internal implementation will be used)
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*/
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define('MATH_BIGINTEGER_MODE_GMP', 3);
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/**#@-*/
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/**
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* The largest digit that may be used in addition / subtraction
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*
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* (we do pow(2, 52) instead of using 4503599627370496, directly, because some PHP installations
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* will truncate 4503599627370496)
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*
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* @access private
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*/
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define('MATH_BIGINTEGER_MAX_DIGIT52', pow(2, 52));
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/**
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* Karatsuba Cutoff
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*
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* At what point do we switch between Karatsuba multiplication and schoolbook long multiplication?
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*
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* @access private
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*/
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define('MATH_BIGINTEGER_KARATSUBA_CUTOFF', 25);
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/**
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* Pure-PHP arbitrary precision integer arithmetic library. Supports base-2, base-10, base-16, and base-256
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* numbers.
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*
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* @author Jim Wigginton <terrafrost@php.net>
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* @version 1.0.0RC4
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* @access public
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* @package Math_BigInteger
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*/
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class Math_BigInteger {
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/**
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* Holds the BigInteger's value.
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*
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* @var Array
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* @access private
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*/
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var $value;
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/**
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* Holds the BigInteger's magnitude.
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*
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* @var Boolean
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* @access private
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*/
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var $is_negative = false;
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/**
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* Random number generator function
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*
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* @see setRandomGenerator()
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* @access private
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*/
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var $generator = 'mt_rand';
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/**
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* Precision
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*
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* @see setPrecision()
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* @access private
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*/
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var $precision = -1;
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/**
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* Precision Bitmask
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*
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* @see setPrecision()
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* @access private
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*/
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var $bitmask = false;
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/**
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* Mode independant value used for serialization.
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*
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* If the bcmath or gmp extensions are installed $this->value will be a non-serializable resource, hence the need for
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* a variable that'll be serializable regardless of whether or not extensions are being used. Unlike $this->value,
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* however, $this->hex is only calculated when $this->__sleep() is called.
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*
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* @see __sleep()
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* @see __wakeup()
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* @var String
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* @access private
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*/
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var $hex;
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/**
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* Converts base-2, base-10, base-16, and binary strings (eg. base-256) to BigIntegers.
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*
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* If the second parameter - $base - is negative, then it will be assumed that the number's are encoded using
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* two's compliment. The sole exception to this is -10, which is treated the same as 10 is.
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*
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* Here's an example:
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* <code>
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* <?php
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* include('Math/BigInteger.php');
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*
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* $a = new Math_BigInteger('0x32', 16); // 50 in base-16
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*
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* echo $a->toString(); // outputs 50
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* ?>
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* </code>
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*
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* @param optional $x base-10 number or base-$base number if $base set.
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* @param optional integer $base
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* @return Math_BigInteger
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* @access public
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*/
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function Math_BigInteger($x = 0, $base = 10)
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{
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if ( !defined('MATH_BIGINTEGER_MODE') ) {
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switch (true) {
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case extension_loaded('gmp'):
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define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_GMP);
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break;
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case extension_loaded('bcmath'):
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define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_BCMATH);
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break;
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default:
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define('MATH_BIGINTEGER_MODE', MATH_BIGINTEGER_MODE_INTERNAL);
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}
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}
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switch ( MATH_BIGINTEGER_MODE ) {
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case MATH_BIGINTEGER_MODE_GMP:
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if (is_resource($x) && get_resource_type($x) == 'GMP integer') {
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$this->value = $x;
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return;
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}
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$this->value = gmp_init(0);
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break;
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case MATH_BIGINTEGER_MODE_BCMATH:
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$this->value = '0';
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break;
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default:
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$this->value = array();
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}
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if (empty($x)) {
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return;
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}
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switch ($base) {
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case -256:
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if (ord($x[0]) & 0x80) {
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$x = ~$x;
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$this->is_negative = true;
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}
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case 256:
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switch ( MATH_BIGINTEGER_MODE ) {
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case MATH_BIGINTEGER_MODE_GMP:
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$sign = $this->is_negative ? '-' : '';
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$this->value = gmp_init($sign . '0x' . bin2hex($x));
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break;
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case MATH_BIGINTEGER_MODE_BCMATH:
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// round $len to the nearest 4 (thanks, DavidMJ!)
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$len = (strlen($x) + 3) & 0xFFFFFFFC;
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$x = str_pad($x, $len, chr(0), STR_PAD_LEFT);
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for ($i = 0; $i < $len; $i+= 4) {
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$this->value = bcmul($this->value, '4294967296', 0); // 4294967296 == 2**32
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$this->value = bcadd($this->value, 0x1000000 * ord($x[$i]) + ((ord($x[$i + 1]) << 16) | (ord($x[$i + 2]) << 8) | ord($x[$i + 3])), 0);
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}
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if ($this->is_negative) {
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$this->value = '-' . $this->value;
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}
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break;
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// converts a base-2**8 (big endian / msb) number to base-2**26 (little endian / lsb)
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default:
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while (strlen($x)) {
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$this->value[] = $this->_bytes2int($this->_base256_rshift($x, 26));
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}
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}
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if ($this->is_negative) {
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if (MATH_BIGINTEGER_MODE != MATH_BIGINTEGER_MODE_INTERNAL) {
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$this->is_negative = false;
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}
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$temp = $this->add(new Math_BigInteger('-1'));
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$this->value = $temp->value;
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}
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break;
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case 16:
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case -16:
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if ($base > 0 && $x[0] == '-') {
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$this->is_negative = true;
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$x = substr($x, 1);
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}
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$x = preg_replace('#^(?:0x)?([A-Fa-f0-9]*).*#', '$1', $x);
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$is_negative = false;
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if ($base < 0 && hexdec($x[0]) >= 8) {
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$this->is_negative = $is_negative = true;
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$x = bin2hex(~pack('H*', $x));
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}
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switch ( MATH_BIGINTEGER_MODE ) {
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case MATH_BIGINTEGER_MODE_GMP:
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$temp = $this->is_negative ? '-0x' . $x : '0x' . $x;
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$this->value = gmp_init($temp);
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$this->is_negative = false;
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break;
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case MATH_BIGINTEGER_MODE_BCMATH:
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$x = ( strlen($x) & 1 ) ? '0' . $x : $x;
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$temp = new Math_BigInteger(pack('H*', $x), 256);
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$this->value = $this->is_negative ? '-' . $temp->value : $temp->value;
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$this->is_negative = false;
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break;
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default:
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$x = ( strlen($x) & 1 ) ? '0' . $x : $x;
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$temp = new Math_BigInteger(pack('H*', $x), 256);
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$this->value = $temp->value;
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}
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if ($is_negative) {
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$temp = $this->add(new Math_BigInteger('-1'));
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$this->value = $temp->value;
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}
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break;
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case 10:
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case -10:
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$x = preg_replace('#^(-?[0-9]*).*#' |