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)
}

func indexBytePortable(s []byte, c byte) int {
	for i, b := range s {
		if b == c {
			return i
		}
	}
	return -1

		Equal(b[len(b)-i:], b[:i])
	}
}

func TestIndexByteNearPageBoundary(t *testing.T) {
	t.Parallel()
	b := dangerousSlice(t)
	for i := range b {
		idx := IndexByte(b[i:], 1)
		if idx != -1 {
			t.Fatalf("IndexByte(b[%d:])=%d, want -1\n", i, idx)
		}
	}
}

func TestIndexNearPageBoundary(t *testing.T) {
	t.Parallel()
	q := dangerousSlice(t)
	if len(q) > 64 {

			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 {

	limit := dirent.Reclen - fixedHdr
	if limit > nameBufLen {
		limit = nameBufLen
	}
	// Avoid bugs in long file names
	// https://github.com/golang/tools/commit/5f9a5413737ba4b4f692214aebee582b47c8be74
	nameLen := bytes.IndexByte(nameBuf[:limit], 0)
	if nameLen < 0 {
		return 0, fmt.Errorf("failed to find terminating 0 byte in dirent")
	}
	return uint64(nameLen), nil

	}
	const projSeg = "/projects/"
	i := strings.Index(u.Path, projSeg)
	if i == -1 {
		return nil, fmt.Errorf("webhook URL %s doesn't contain the projects segment", u)
	}
	i += len(projSeg)
	j := strings.IndexByte(u.Path[i:], '/')
	if j == -1 {
		return nil, fmt.Errorf("webhook URL %s is malformed", u)
	}
	ret.gcpProject = u.Path[i : i+j]

	const crSeg = "/ISTIO_META_CLOUDRUN_ADDR/"
	i += j

	input := bufio.NewScanner(bytes.NewReader(valueBuffer.Bytes()))
	for input.Scan() {
		line := strings.TrimSpace(input.Text())
		if line == "" {
			continue
		}
		// Find first separator.
		idx := strings.IndexByte(line, trailerKVSeparator[0])
		if idx <= 0 || idx >= len(line) {
			if cr.debug {
				fmt.Printf("Could not find separator, got %q\n", line)
			}
			return errMalformedEncoding
		}

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}
	}

// list with an empty final value but stops at the token "STOP".
func ExampleScanner_earlyStop() {
	onComma := func(data []byte, atEOF bool) (advance int, token []byte, err error) {
		i := bytes.IndexByte(data, ',')
		if i == -1 {
			if !atEOF {
				return 0, nil, nil
			}
			// If we have reached the end, return the last token.
			return 0, data, bufio.ErrFinalToken
		}

	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)
	}

		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 contextCanceled(ctx) {
			return ctx.Err()
		}
		if opts.Limit > 0 && objsReturned >= opts.Limit {
			return nil
		}