code: long readLong()
      throws IOException
    {
      return (((long) _is.read() << 56) |
              ((long) _is.read() << 48) |
              ((long) _is.read() << 40) |
              ((long) _is.read() << 32) |
              ((long) _is.read() << 24) |
              ((long) _is.read() << 16) |
              ((long) _is.read() << 8) |
              ((long) _is.read()));
    }
docs: Parses a 64-bit int.