static public boolean readMagic(InputStream is) throws IOException {
		byte[] buffer = new byte[4];

		realRead(is, buffer, 4);
		if (!Arrays.equals(buffer, CHIB)) {
			return false;
		}

		realRead(is, buffer, 4);
		if (!Arrays.equals(buffer, IOEK)) {
			return false;
		}

		return true;
	}