// has been uploaded using the S3 singlepart API.
//
// Parts may panic if the ETag is an invalid multipart
// ETag.
func (e ETag) Parts() int {
	if !e.IsMultipart() {
		return 1
	}

	n := bytes.IndexRune(e, '-')
	parts, err := strconv.Atoi(string(e[n+1:]))
	if err != nil {
		panic(err) // malformed ETag
	}
	return parts
}

// Format returns an ETag that is formatted as specified
// by AWS S3.
//

	fmt.Println(bytes.IndexAny([]byte("crwth"), "aeiouy"))
	// Output:
	// 2
	// -1
}

func ExampleIndexRune() {
	fmt.Println(bytes.IndexRune([]byte("chicken"), 'k'))
	fmt.Println(bytes.IndexRune([]byte("chicken"), 'd'))
	// Output:
	// 4
	// -1
}

func ExampleJoin() {
	s := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}

	return bytealg.LastIndexByte(s, c)
}

// IndexRune interprets s as a sequence of UTF-8-encoded code points.
// It returns the byte index of the first occurrence in s of the given rune.
// It returns -1 if rune is not present in s.
// If r is [utf8.RuneError], it returns the first instance of any
// invalid UTF-8 byte sequence.
func IndexRune(s []byte, r rune) int {
	const haveFastIndex = bytealg.MaxBruteForce > 0

func predefine(defines flags.MultiFlag) map[string]*Macro {
	macros := make(map[string]*Macro)
	for _, name := range defines {
		value := "1"
		i := strings.IndexRune(name, '=')
		if i > 0 {
			name, value = name[:i], name[i+1:]
		}
		tokens := Tokenize(name)
		if len(tokens) != 1 || tokens[0].ScanToken != scanner.Ident {