<?php

/**
 * PHPExcel_Reader_Excel5_MD5
 *
 * Copyright (c) 2006 - 2015 PHPExcel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * @category   PHPExcel
 * @package    PHPExcel_Reader_Excel5
 * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt        LGPL
 * @version    ##VERSION##, ##DATE##
 */
class PHPExcel_Reader_Excel5_MD5
{
  // Context
  private $a;
  private $b;
  private $c;
  private $d;
  
  /**
   * MD5 stream constructor
   */
  public function __construct()
  {
    $this->reset ();
  }
  
  /**
   * Reset the MD5 stream context
   */
  public function reset()
  {
    $this->a = 0x67452301;
    $this->b = 0xEFCDAB89;
    $this->c = 0x98BADCFE;
    $this->d = 0x10325476;
  }
  
  /**
   * Get MD5 stream context
   *
   * @return string
   */
  public function getContext()
  {
    $s = '';
    foreach ( array (
        'a',
        'b',
        'c',
        'd' 
    ) as $i )
    {
      $v = $this->{$i};
      $s .= chr ( $v & 0xff );
      $s .= chr ( ($v >> 8) & 0xff );
      $s .= chr ( ($v >> 16) & 0xff );
      $s .= chr ( ($v >> 24) & 0xff );
    }
    
    return $s;
  }
  
  /**
   * Add data to context
   *
   * @param string $data
   *          Data to add
   */
  public function add($data)
  {
    $words = array_values ( unpack ( 'V16', $data ) );
    
    $A = $this->a;
    $B = $this->b;
    $C = $this->c;
    $D = $this->d;
    
    $F = array (
        'PHPExcel_Reader_Excel5_MD5',
        'f' 
    );
    $G = array (
        'PHPExcel_Reader_Excel5_MD5',
        'g' 
    );
    $H = array (
        'PHPExcel_Reader_Excel5_MD5',
        'h' 
    );
    $I = array (
        'PHPExcel_Reader_Excel5_MD5',
        'i' 
    );
    
    /* ROUND 1 */
    self::step ( $F, $A, $B, $C, $D, $words [0], 7, 0xd76aa478 );
    self::step ( $F, $D, $A, $B, $C, $words [1], 12, 0xe8c7b756 );
    self::step ( $F, $C, $D, $A, $B, $words [2], 17, 0x242070db );
    self::step ( $F, $B, $C, $D, $A, $words [3], 22, 0xc1bdceee );
    self::step ( $F, $A, $B, $C, $D, $words [4], 7, 0xf57c0faf );
    self::step ( $F, $D, $A, $B, $C, $words [5], 12, 0x4787c62a );
    self::step ( $F, $C, $D, $A, $B, $words [6], 17, 0xa8304613 );
    self::step ( $F, $B, $C, $D, $A, $words [7], 22, 0xfd469501 );
    self::step ( $F, $A, $B, $C, $D, $words [8], 7, 0x698098d8 );
    self::step ( $F, $D, $A, $B, $C, $words [9], 12, 0x8b44f7af );
    self::step ( $F, $C, $D, $A, $B, $words [10], 17, 0xffff5bb1 );
    self::step ( $F, $B, $C, $D, $A, $words [11], 22, 0x895cd7be );
    self::step ( $F, $A, $B, $C, $D, $words [12], 7, 0x6b901122 );
    self::step ( $F, $D, $A, $B, $C, $words [13], 12, 0xfd987193 );
    self::step ( $F, $C, $D, $A, $B, $words [14], 17, 0xa679438e );
    self::step ( $F, $B, $C, $D, $A, $words [15], 22, 0x49b40821 );
    
    /* ROUND 2 */
    self::step ( $G, $A, $B, $C, $D, $words [1], 5, 0xf61e2562 );
    self::step ( $G, $D, $A, $B, $C, $words [6], 9, 0xc040b340 );
    self::step ( $G, $C, $D, $A, $B, $words [11], 14, 0x265e5a51 );
    self::step ( $G, $B, $C, $D, $A, $words [0], 20, 0xe9b6c7aa );
    self::step ( $G, $A, $B, $C, $D, $words [5], 5, 0xd62f105d );
    self::step ( $G, $D, $A, $B, $C, $words [10], 9, 0x02441453 );
    self::step ( $G, $C, $D, $A, $B, $words [15], 14, 0xd8a1e681 );
    self::step ( $G, $B, $C, $D, $A, $words [4], 20, 0xe7d3fbc8 );
    self::step ( $G, $A, $B, $C, $D, $words [9], 5, 0x21e1cde6 );
    self::step ( $G, $D, $A, $B, $C, $words [14], 9, 0xc33707d6 );
    self::step ( $G, $C, $D, $A, $B, $words [3], 14, 0xf4d50d87 );
    self::step ( $G, $B, $C, $D, $A, $words [8], 20, 0x455a14ed );
    self::step ( $G, $A, $B, $C, $D, $words [13], 5, 0xa9e3e905 );
    self::step ( $G, $D, $A, $B, $C, $words [2], 9, 0xfcefa3f8 );
    self::step ( $G, $C, $D, $A, $B, $words [7], 14, 0x676f02d9 );
    self::step ( $G, $B, $C, $D, $A, $words [12], 20, 0x8d2a4c8a );
    
    /* ROUND 3 */
    self::step ( $H, $A, $B, $C, $D, $words [5], 4, 0xfffa3942 );
    self::step ( $H, $D, $A, $B, $C, $words [8], 11, 0x8771f681 );
    self::step ( $H, $C, $D, $A, $B, $words [11], 16, 0x6d9d6122 );
    self::step ( $H, $B, $C, $D, $A, $words [14], 23, 0xfde5380c );
    self::step ( $H, $A, $B, $C, $D, $words [1], 4, 0xa4beea44 );
    self::step ( $H, $D, $A, $B, $C, $words [4], 11, 0x4bdecfa9 );
    self::step ( $H, $C, $D, $A, $B, $words [7], 16, 0xf6bb4b60 );
    self::step ( $H, $B, $C, $D, $A, $words [10], 23, 0xbebfbc70 );
    self::step ( $H, $A, $B, $C, $D, $words [13], 4, 0x289b7ec6 );
    self::step ( $H, $D, $A, $B, $C, $words [0], 11, 0xeaa127fa );
    self::step ( $H, $C, $D, $A, $B, $words [3], 16, 0xd4ef3085 );
    self::step ( $H, $B, $C, $D, $A, $words [6], 23, 0x04881d05 );
    self::step ( $H, $A, $B, $C, $D, $words [9], 4, 0xd9d4d039 );
    self::step ( $H, $D, $A, $B, $C, $words [12], 11, 0xe6db99e5 );
    self::step ( $H, $C, $D, $A, $B, $words [15], 16, 0x1fa27cf8 );
    self::step ( $H, $B, $C, $D, $A, $words [2], 23, 0xc4ac5665 );
    
    /* ROUND 4 */
    self::step ( $I, $A, $B, $C, $D, $words [0], 6, 0xf4292244 );
    self::step ( $I, $D, $A, $B, $C, $words [7], 10, 0x432aff97 );
    self::step ( $I, $C, $D, $A, $B, $words [14], 15, 0xab9423a7 );
    self::step ( $I, $B, $C, $D, $A, $words [5], 21, 0xfc93a039 );
    self::step ( $I, $A, $B, $C, $D, $words [12], 6, 0x655b59c3 );
    self::step ( $I, $D, $A, $B, $C, $words [3], 10, 0x8f0ccc92 );
    self::step ( $I, $C, $D, $A, $B, $words [10], 15, 0xffeff47d );
    self::step ( $I, $B, $C, $D, $A, $words [1], 21, 0x85845dd1 );
    self::step ( $I, $A, $B, $C, $D, $words [8], 6, 0x6fa87e4f );
    self::step ( $I, $D, $A, $B, $C, $words [15], 10, 0xfe2ce6e0 );
    self::step ( $I, $C, $D, $A, $B, $words [6], 15, 0xa3014314 );
    self::step ( $I, $B, $C, $D, $A, $words [13], 21, 0x4e0811a1 );
    self::step ( $I, $A, $B, $C, $D, $words [4], 6, 0xf7537e82 );
    self::step ( $I, $D, $A, $B, $C, $words [11], 10, 0xbd3af235 );
    self::step ( $I, $C, $D, $A, $B, $words [2], 15, 0x2ad7d2bb );
    self::step ( $I, $B, $C, $D, $A, $words [9], 21, 0xeb86d391 );
    
    $this->a = ($this->a + $A) & 0xffffffff;
    $this->b = ($this->b + $B) & 0xffffffff;
    $this->c = ($this->c + $C) & 0xffffffff;
    $this->d = ($this->d + $D) & 0xffffffff;
  }
  private static function f($X, $Y, $Z)
  {
    return (($X & $Y) | ((~ $X) & $Z)); // X AND Y OR NOT X AND Z
  }
  private static function g($X, $Y, $Z)
  {
    return (($X & $Z) | ($Y & (~ $Z))); // X AND Z OR Y AND NOT Z
  }
  private static function h($X, $Y, $Z)
  {
    return ($X ^ $Y ^ $Z); // X XOR Y XOR Z
  }
  private static function i($X, $Y, $Z)
  {
    return ($Y ^ ($X | (~ $Z))); // Y XOR (X OR NOT Z)
  }
  private static function step($func, &$A, $B, $C, $D, $M, $s, $t)
  {
    $A = ($A + call_user_func ( $func, $B, $C, $D ) + $M + $t) & 0xffffffff;
    $A = self::rotate ( $A, $s );
    $A = ($B + $A) & 0xffffffff;
  }
  private static function rotate($decimal, $bits)
  {
    $binary = str_pad ( decbin ( $decimal ), 32, "0", STR_PAD_LEFT );
    return bindec ( substr ( $binary, $bits ) . substr ( $binary, 0, $bits ) );
  }
}
