protected static boolean isFree(byte data, int index) {
protected static boolean isFree(byte[] data, int index) { int byteIndex  = index / 8; byte bitIndex  = (byte) (index % 8); byte mask = (byte) (1 << bitIndex);
	protected static boolean isFree(byte data, int index) {		//byte bitIndex  = (byte) (index % 8);				byte mask = (byte) (1 << index);		return ((data & mask) == 0)? true : false;	}