// returning nil instead of empty slice if all spaces.
		return nil
	}
	return s[start:stop]
}

// Runes interprets s as a sequence of UTF-8-encoded code points.
// It returns a slice of runes (Unicode code points) equivalent to s.
func Runes(s []byte) []rune {
	t := make([]rune, utf8.RuneCount(s))
	i := 0
	for len(s) > 0 {
		r, l := utf8.DecodeRune(s)
		t[i] = r
		i++
		s = s[l:]
	}

}

// append single byte to scratch buffer
func (s *scratch) add(c byte) {
	if s.fill+1 >= cap(s.data) {
		s.grow()
	}

	s.data[s.fill] = c
	s.fill++
}

// append encoded rune to scratch buffer
func (s *scratch) addRune(r rune) int {
	if s.fill+utf8.UTFMax >= cap(s.data) {
		s.grow()
	}

	n := utf8.EncodeRune(s.data[s.fill:], r)
	s.fill += n
	return n

			if (len(args) == 1) != (configDumpFile == "") {
				cmd.Println(cmd.UsageString())
				return fmt.Errorf("cluster requires pod name or --file parameter")
			}
			return nil
		},
		RunE: func(c *cobra.Command, args []string) error {
			kubeClient, err := ctx.CLIClient()
			if err != nil {
				return err
			}
			var configWriter *configdump.ConfigWriter
			if len(args) == 1 {

// converted to int they correspond to the rune size that was read.
type readOp int8

// Don't use iota for these, as the values need to correspond with the
// names and comments, which is easier to see when being explicit.
const (
	opRead      readOp = -1 // Any other read operation.
	opInvalid   readOp = 0  // Non-read operation.
	opReadRune1 readOp = 1  // Read rune of size 1.
	opReadRune2 readOp = 2  // Read rune of size 2.

  		 istioctl waypoint status --namespace default`,
		Args: func(cmd *cobra.Command, args []string) error {
			if len(args) != 0 {
				return fmt.Errorf("unknown subcommand %q", args[0])
			}
			return nil
		},
		RunE: func(cmd *cobra.Command, args []string) error {
			kubeClient, err := ctx.CLIClient()
			if err != nil {
				return fmt.Errorf("failed to create Kubernetes client: %v", err)
			}

  istioctl ztunnel-config certificates <ztunnel-name[.namespace]> -o json
`,
		Aliases: []string{"certificates", "certs", "cert"},
		Args:    common.validateArgs,
		RunE: runConfigDump(ctx, common, func(cw *ztunnelDump.ConfigWriter) error {
			switch common.outputFormat {
			case summaryOutput:
				return cw.PrintSecretSummary()
			case jsonOutput, yamlOutput:

	//
	//	R1
	//	offset
	//	$offset
	// Every piece is optional, so we scan left to right and what
	// we discover tells us where we are.

	// Prefix: $.
	var prefix rune
	switch tok := p.peek(); tok {
	case '$', '*':
		prefix = rune(tok)
		p.next()
	}

	// Symbol: sym±offset(SB)
	tok := p.next()
	name := tok.String()
	if tok.ScanToken == scanner.Ident && !p.atStartOfRegister(name) {

		}
	})
	if n > 0 {
		t.Errorf("allocations occurred while appending")
	}
}

func TestRuneIO(t *testing.T) {
	const NRune = 1000
	// Built a test slice while we write the data
	b := make([]byte, utf8.UTFMax*NRune)
	var buf Buffer
	n := 0
	for r := rune(0); r < NRune; r++ {
		size := utf8.EncodeRune(b[n:], r)
		nbytes, err := buf.WriteRune(r)
		if err != nil {
			t.Fatalf("WriteRune(%U) error: %s", r, err)

		return err
	} else if match {
		return nil
	}

	// normalize the name to letters, digits, _ or $
	valid := true
	cleaned := strings.Map(func(r rune) rune {
		switch {
		case unicode.IsLetter(r):
			return 'a'
		case unicode.IsDigit(r):
			return '0'
		case r == '_', r == '$':
			return r
		default:
			valid = false
			return -1
		}

			return string(strconv.AppendInt(append([]byte(frame.File), ':'), int64(frame.Line), 10))
		}
	}

	return ""
}

func IsValidDBNameChar(c rune) bool {
	return !unicode.IsLetter(c) && !unicode.IsNumber(c) && c != '.' && c != '*' && c != '_' && c != '$' && c != '@'
}

// CheckTruth check string true or not
func CheckTruth(vals ...string) bool {