Returns the (start, stop) index for the viewing area of the
        byte stream.

        :param int index: start index of the viewing area.
            Default is the begin of the stream.
        :param int count: number of bytes to view.
            Default is to the end of the stream.

def _view_area(stream=bytes(), index=0, count=0):
        """ Returns the (start, stop) index for the viewing area of the
        byte stream.

        :param int index: start index of the viewing area.
            Default is the begin of the stream.
        :param int count: number of bytes to view.
            Default is to the end of the stream.
        """
        # Byte stream size
        size = len(stream)

        # Start index of the viewing area
        start = max(min(index, size), -size)
        if start < 0:
            start += size

        # Stop index of the viewing area
        if not count:
            count = size
        if count > 0:
            stop = min(start + count, size)
        else:
            stop = size

        return start, stop