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   1  <?php
   2  /*
   3   * This file is part of the PHPASN1 library.
   4   *
   5   * For the full copyright and license information, please view the LICENSE
   6   * file that was distributed with this source code.
   7   */
   8  
   9  namespace FG\Utility;
  10  
  11  /**
  12   * Class BigIntegerBcmath
  13   * Integer representation of big numbers using the bcmath library to perform large operations.
  14   * @package FG\Utility
  15   * @internal
  16   */
  17  class BigIntegerBcmath extends BigInteger
  18  {
  19      protected $_str;
  20  
  21      public function __clone()
  22      {
  23          // nothing needed to copy
  24      }
  25  
  26      protected function _fromString($str)
  27      {
  28          $this->_str = (string)$str;
  29      }
  30  
  31      protected function _fromInteger($integer)
  32      {
  33          $this->_str = (string)$integer;
  34      }
  35  
  36      public function __toString()
  37      {
  38          return $this->_str;
  39      }
  40  
  41      public function toInteger()
  42      {
  43          if ($this->compare(PHP_INT_MAX) > 0 || $this->compare(PHP_INT_MIN) < 0) {
  44              throw new \OverflowException(sprintf('Can not represent %s as integer.', $this->_str));
  45          }
  46          return (int)$this->_str;
  47      }
  48  
  49      public function isNegative()
  50      {
  51          return bccomp($this->_str, '0', 0) < 0;
  52      }
  53  
  54      protected function _unwrap($number)
  55      {
  56          if ($number instanceof self) {
  57              return $number->_str;
  58          }
  59          return $number;
  60      }
  61  
  62      public function compare($number)
  63      {
  64          return bccomp($this->_str, $this->_unwrap($number), 0);
  65      }
  66  
  67      public function add($b)
  68      {
  69          $ret = new self();
  70          $ret->_str = bcadd($this->_str, $this->_unwrap($b), 0);
  71          return $ret;
  72      }
  73  
  74      public function subtract($b)
  75      {
  76          $ret = new self();
  77          $ret->_str = bcsub($this->_str, $this->_unwrap($b), 0);
  78          return $ret;
  79      }
  80  
  81      public function multiply($b)
  82      {
  83          $ret = new self();
  84          $ret->_str = bcmul($this->_str, $this->_unwrap($b), 0);
  85          return $ret;
  86      }
  87  
  88      public function modulus($b)
  89      {
  90          $ret = new self();
  91          if ($this->isNegative()) {
  92              // bcmod handles negative numbers differently
  93              $b = $this->_unwrap($b);
  94              $ret->_str = bcsub($b, bcmod(bcsub('0', $this->_str, 0), $b), 0);
  95          }
  96          else {
  97              $ret->_str = bcmod($this->_str, $this->_unwrap($b));
  98          }
  99          return $ret;
 100      }
 101  
 102      public function toPower($b)
 103      {
 104          $ret = new self();
 105          $ret->_str = bcpow($this->_str, $this->_unwrap($b), 0);
 106          return $ret;
 107      }
 108  
 109      public function shiftRight($bits = 8)
 110      {
 111          $ret = new self();
 112          $ret->_str = bcdiv($this->_str, bcpow('2', $bits));
 113          return $ret;
 114      }
 115  
 116      public function shiftLeft($bits = 8) {
 117          $ret = new self();
 118          $ret->_str = bcmul($this->_str, bcpow('2', $bits));
 119          return $ret;
 120      }
 121  
 122      public function absoluteValue()
 123      {
 124          $ret = new self();
 125          if (-1 === bccomp($this->_str, '0', 0)) {
 126              $ret->_str = bcsub('0', $this->_str, 0);
 127          }
 128          else {
 129              $ret->_str = $this->_str;
 130          }
 131          return $ret;
 132      }
 133  }