}

func (f Format) String() string {
	var ss []string
	for f2 := Format(1); f2 < formatMax; f2 <<= 1 {
		if f.has(f2) {
			ss = append(ss, formatNames[f2])
		}
	}
	switch len(ss) {
	case 0:
		return "<unknown>"
	case 1:
		return ss[0]
	default:
		return "(" + strings.Join(ss, " | ") + ")"
	}
}

// Magics used to identify various formats.
const (