switch len(ss) {
	case 0:
		return "<unknown>"
	case 1:
		return ss[0]
	default:
		return "(" + strings.Join(ss, " | ") + ")"
	}
}

// Magics used to identify various formats.
const (
	magicGNU, versionGNU     = "ustar ", " \x00"
	magicUSTAR, versionUSTAR = "ustar\x00", "00"
	trailerSTAR              = "tar\x00"
)

// Size constants from various tar specifications.
const (