b1[j] = 'x'
			pos := IndexByte(b1, 'x')
			if pos != j {
				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
			}
			b1[j] = 0
			pos = IndexByte(b1, 'x')
			if pos != -1 {
				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
			}
		}
		// different end alignments
		b1 = b[:i]
		for j := 0; j < len(b1); j++ {
			b1[j] = 'x'
			pos := IndexByte(b1, 'x')
			if pos != j {

// It stops as soon as a call to f returns true.
func ContainsFunc(b []byte, f func(rune) bool) bool {
	return IndexFunc(b, f) >= 0
}

// IndexByte returns the index of the first instance of c in b, or -1 if c is not present in b.
func IndexByte(b []byte, c byte) int {
	return bytealg.IndexByte(b, c)
}

// LastIndex returns the index of the last instance of sep in s, or -1 if sep is not present in s.
func LastIndex(s, sep []byte) int {

// It returns a single-use iterator.
func Lines(s []byte) iter.Seq[[]byte] {
	return func(yield func([]byte) bool) {
		for len(s) > 0 {
			var line []byte
			if i := IndexByte(s, '\n'); i >= 0 {
				line, s = s[:i+1], s[i+1:]
			} else {
				line, s = s, nil
			}
			if !yield(line[:len(line):len(line)]) {
				return
			}
		}
	}
}

	line = append(line, slice...)
	return line, err
}

// readSlice is like ReadBytes but returns a reference to internal buffer data.
func (b *Buffer) readSlice(delim byte) (line []byte, err error) {
	i := IndexByte(b.buf[b.off:], delim)
	end := b.off + i + 1
	if i < 0 {
		end = len(b.buf)
		err = io.EOF
	}
	line = b.buf[b.off:end]
	b.off = end
	b.lastRead = opRead
	return line, err
}

			k := strings.TrimSpace(strings.ToUpper(v[0]))
			if k == "INDEX" || k == "UNIQUEINDEX" {
				var (
					name       string
					tag        = strings.Join(v[1:], ":")
					idx        = strings.IndexByte(tag, ',')
					tagSetting = strings.Join(strings.Split(tag, ",")[1:], ",")
					settings   = ParseTagSetting(tagSetting, ",")
					length, _  = strconv.Atoi(settings["LENGTH"])
				)

				if idx == -1 {

func ParseUnverifiedStandardClaims(token []byte, claims *StandardClaims, buf []byte) (*SigningMethodHMAC, error) {
	if bytes.Count(token, []byte(".")) != 2 {
		return nil, jwtgo.ErrSignatureInvalid
	}

	i := bytes.IndexByte(token, '.')
	j := bytes.LastIndexByte(token, '.')

	n, err := base64DecodeBytes(token[:i], buf)
	if err != nil {
		return nil, &jwtgo.ValidationError{Inner: err, Errors: jwtgo.ValidationErrorMalformed}
	}

	fmt.Println(bytes.Index([]byte("chicken"), []byte("dmr")))
	// Output:
	// 4
	// -1
}

func ExampleIndexByte() {
	fmt.Println(bytes.IndexByte([]byte("chicken"), byte('k')))
	fmt.Println(bytes.IndexByte([]byte("chicken"), byte('g')))
	// Output:
	// 4
	// -1
}

func ExampleIndexFunc() {
	f := func(c rune) bool {
		return unicode.Is(unicode.Han, c)
	}

}

// parseString parses bytes as a NUL-terminated C-style string.
// If a NUL byte is not found then the whole slice is returned as a string.
func (*parser) parseString(b []byte) string {
	if i := bytes.IndexByte(b, 0); i >= 0 {
		return string(b[:i])
	}
	return string(b)
}

// formatString copies s into b, NUL-terminating if possible.
func (f *formatter) formatString(b []byte, s string) {
	if len(s) > len(b) {

		forward := ""
		if len(opts.ForwardTo) > 0 && strings.HasPrefix(opts.ForwardTo, current) {
			forward = strings.TrimPrefix(opts.ForwardTo, current)
			// Trim further directories and trailing slash.
			if idx := strings.IndexByte(forward, '/'); idx > 0 {
				forward = forward[:idx]
			}
		}

		if s.walkMu != nil {
			s.walkMu.Lock()
		}
		entries, err := s.ListDir(ctx, "", opts.Bucket, current, -1)
		if s.walkMu != nil {

// newline.
func ScanLines(data []byte, atEOF bool) (advance int, token []byte, err error) {
	if atEOF && len(data) == 0 {
		return 0, nil, nil
	}
	if i := bytes.IndexByte(data, '\n'); i >= 0 {
		// We have a full newline-terminated line.
		return i + 1, dropCR(data[0:i]), nil
	}
	// If we're at EOF, we have a final, non-terminated line. Return it.
	if atEOF {