Return full path to filename prefix (i.e. without dot extension)
    represented by given :class:`datetime.datetime` object.

def time2fname(tstamp, full=False):
    """Return full path to filename prefix (i.e. without dot extension)
    represented by given :class:`datetime.datetime` object."""
    result = tstamp.strftime(FILENAME_FORMAT)
    result = result if not full else join(time2dir(tstamp), result)
    return result