def jfif_stream_size(node=None, parent=None, attr_index=None, rawdata=None,
    new_value=None, **kwargs):
    """Size getter/setter for the size of a jfif data stream."""
    if parent is None:
        return 0
    if new_value is None:
        return parent.stream_len - 2
    else:
        parent.stream_len = new_value + 2
