def METHOD_NAME(self):
    #
    # get a IPTC field header
    s = self.fp.read(5)
    if not len(s):
        return None, 0
    tag = i8(s[1]), i8(s[2])
    # syntax
    if i8(s[0]) != 0x1C or tag[0] < 1 or tag[0] > 9:
        raise SyntaxError("invalid IPTC/NAA file")
    # field size
    size = i8(s[3])
    if size > 132:
        raise IOError("illegal field length in IPTC/NAA file")
    elif size == 128:
        size = 0
    elif size > 128:
        size = i(self.fp.read(size - 128))
    else:
        size = i16(s[3:])
    return tag, size