<?php
/**
 * PHPExcel
 *
 * 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_Shared
 * @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##
 */

/**
 * PHPExcel_Shared_PasswordHasher
 *
 * @category PHPExcel
 * @package PHPExcel_Shared
 * @copyright Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
 */
class PHPExcel_Shared_PasswordHasher
{
  /**
   * Create a password hash from a given string.
   *
   * This method is based on the algorithm provided by
   * Daniel Rentz of OpenOffice and the PEAR package
   * Spreadsheet_Excel_Writer by Xavier Noguer <xnoguer@rezebra.com>.
   *
   * @param string $pPassword
   *          Password to hash
   * @return string Hashed password
   */
  public static function hashPassword($pPassword = '')
  {
    $password = 0x0000;
    $charPos = 1; // char position
                     
    // split the plain text password in its component characters
    $chars = preg_split ( '//', $pPassword, - 1, PREG_SPLIT_NO_EMPTY );
    foreach ( $chars as $char )
    {
      $value = ord ( $char ) << $charPos ++; // shifted ASCII value
      $rotated_bits = $value >> 15; // rotated bits beyond bit 15
      $value &= 0x7fff; // first 15 bits
      $password ^= ($value | $rotated_bits);
    }
    
    $password ^= strlen ( $pPassword );
    $password ^= 0xCE4B;
    
    return (strtoupper ( dechex ( $password ) ));
  }
}
