<?php
/**
 * @author      Jan Altensen (Stricted)
 * @copyright   2013-2014 Jan Altensen (Stricted)
 * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
 */
class bcrypt {
	/**
	 * compare password with given hash
	 *
	 * @param	string	$password
	 * @param	string	$hash
	 * @return	boolean
	 */
	public function compare ($password, $hash) {
		$salt = $this->getSalt($hash);
		
		$new = crypt($password, $salt);
		$doubleSalted = crypt(crypt($password, $salt), $salt);
		
		if ($new == $hash) {
			return true;
		}
		else if ($doubleSalted == $hash) {
			return true;
		}
		
		return false;
	}

	/**
	 * crypt new password
	 *
	 * @param	string	$password
	 * @param	string	$double
	 * @return	string
	 */
	public function crypt ($password, $double = false) {
		$salt = $this->generateSalt();
		if ($double) {
			return crypt(crypt($password, $salt), $salt);
		}
		else {
			return crypt($password, $salt);
		}
	}
	
	/**
	 * generate new salt
	 *
	 * @return	string
	 */
	public function generateSalt() {
		$blowfishCharacters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789./';
		$maxIndex = strlen($blowfishCharacters) - 1;
		$salt = '';
		
		for ($i = 0; $i < 22; $i++) {
			$rand = mt_rand(0, $maxIndex);
			$salt .= $blowfishCharacters[$rand];
		}

		return '$2a$08$' . $salt;
	}
	
	/**
	 * get salt from password hash
	 *
	 * @param	string	$hash
	 * @return	string
	 */
	private function getSalt($hash) {
		$salt = '';
		if (mb_substr($hash, 0, 7) == '$2a$08$') {
			$salt = mb_substr($hash, 7, 22);
		}
		else {
			$salt = mb_substr($hash, 0, 22);
		}
		
		return '$2a$08$' . $salt;
	}
}
?>