// using WTF-8 instead of UTF-8 encoding.
func UTF16ToString(s []uint16) string {
	maxLen := 0
	for i, v := range s {
		if v == 0 {
			s = s[0:i]
			break
		}
		switch {
		case v <= rune1Max:
			maxLen += 1
		case v <= rune2Max:
			maxLen += 2
		default:
			// r is a non-surrogate that decodes to 3 bytes,
			// or is an unpaired surrogate (also 3 bytes in WTF-8),

		return
	}

	if !strings.HasPrefix(val, "0x") {
		Exitf("-B argument must start with 0x: %s", val)
	}

	ov := val
	val = val[2:]

	const maxLen = 32
	if hex.DecodedLen(len(val)) > maxLen {
		Exitf("-B option too long (max %d digits): %s", maxLen, ov)
	}

	b, err := hex.DecodeString(val)
	if err != nil {
		if err == hex.ErrLength {
			Exitf("-B argument must have even number of digits: %s", ov)
		}