public function hashCode() {
		$h = $this->hash;
		$l = $this->length();
		if ( $h == 0 && $l > 0 ) {
			for ( $i = 0; $i < $l; $i ++ ) {
				$h = (int) ( 31 * $h + $this->charCodeAt( $i ) );
			}
			$this->hash = $h;
		}

		return $h;
	}