mode := fs.FileMode(m & 0777)
	switch m & s_IFMT {
	case s_IFBLK:
		mode |= fs.ModeDevice
	case s_IFCHR:
		mode |= fs.ModeDevice | fs.ModeCharDevice
	case s_IFDIR:
		mode |= fs.ModeDir
	case s_IFIFO:
		mode |= fs.ModeNamedPipe
	case s_IFLNK:
		mode |= fs.ModeSymlink
	case s_IFREG:
		// nothing to do
	case s_IFSOCK:
		mode |= fs.ModeSocket
	}
	if m&s_ISGID != 0 {

	// Set the magic values.
	switch {
	case format.has(formatV7):
		// Do nothing.
	case format.has(FormatGNU):
		copy(b.toGNU().magic(), magicGNU)
		copy(b.toGNU().version(), versionGNU)
	case format.has(formatSTAR):
		copy(b.toSTAR().magic(), magicUSTAR)
		copy(b.toSTAR().version(), versionUSTAR)
		copy(b.toSTAR().trailer(), trailerSTAR)
	case format.has(FormatUSTAR | FormatPAX):

	switch GOARCH {
	case "386":
		return archX86(&x86.Link386)
	case "amd64":
		return archX86(&x86.Linkamd64)
	case "arm":
		return archArm()
	case "arm64":
		return archArm64()
	case "loong64":
		return archLoong64(&loong64.Linkloong64)
	case "mips":
		return archMips(&mips.Linkmips)
	case "mipsle":
		return archMips(&mips.Linkmipsle)
	case "mips64":
		return archMips64(&mips.Linkmips64)

	// Determine the character encoding.
	utf8Valid1, utf8Require1 := detectUTF8(f.Name)
	utf8Valid2, utf8Require2 := detectUTF8(f.Comment)
	switch {
	case !utf8Valid1 || !utf8Valid2:
		// Name and Comment definitely not UTF-8.
		f.NonUTF8 = true
	case !utf8Require1 && !utf8Require2:
		// Name and Comment use only single-byte runes that overlap with UTF-8.
		f.NonUTF8 = false
	default:

		// Obvious ASCII ones: \t through \r plus space. Plus two Latin-1 oddballs.
		switch r {
		case ' ', '\t', '\n', '\v', '\f', '\r':
			return true
		case '\u0085', '\u00A0':
			return true
		}
		return false
	}
	// High-valued ones.
	if '\u2000' <= r && r <= '\u200a' {
		return true
	}
	switch r {
	case '\u1680', '\u2028', '\u2029', '\u202f', '\u205f', '\u3000':
		return true
	}
	return false
}

		switch in.Stack.Text() {
		case "else", "endif", "ifdef", "ifndef", "line":
			// Press on.
		default:
			return false
		}
	}
	switch in.Stack.Text() {
	case "define":
		in.define()
	case "else":
		in.else_()
	case "endif":
		in.endif()
	case "ifdef":
		in.ifdef(true)
	case "ifndef":
		in.ifdef(false)
	case "include":
		in.include()
	case "line":

}

func (p *Parser) pseudo(word string, operands [][]lex.Token) bool {
	switch word {
	case "DATA":
		p.asmData(operands)
	case "FUNCDATA":
		p.asmFuncData(operands)
	case "GLOBL":
		p.asmGlobl(operands)
	case "PCDATA":
		p.asmPCData(operands)
	case "PCALIGN":
		p.asmPCAlign(operands)
	case "TEXT":
		p.asmText(operands)
	default:
		return false
	}
	return true
}

func Index(s, sep []byte) int {
	n := len(sep)
	switch {
	case n == 0:
		return 0
	case n == 1:
		return IndexByte(s, sep[0])
	case n == len(s):
		if Equal(sep, s) {
			return 0
		}
		return -1
	case n > len(s):
		return -1
	case n <= bytealg.MaxLen:
		// Use brute force when s and sep both are small
		if len(s) <= bytealg.MaxBruteForce {

		}
	}

	n = len(b0) - len(b)
	switch {
	case err == ErrWriteTooLong:
		return n, errMissData // Not possible; implies bug in validation logic
	case err != nil:
		return n, err
	case sw.logicalRemaining() == 0 && sw.physicalRemaining() > 0:
		return n, errUnrefData // Not possible; implies bug in validation logic
	case overwrite:
		return n, ErrWriteTooLong
	default:
		return n, nil
	}
}

	// Output:
	// 8
	// 9
	// -1
}

func ExampleMap() {
	rot13 := func(r rune) rune {
		switch {
		case r >= 'A' && r <= 'Z':
			return 'A' + (r-'A'+13)%26
		case r >= 'a' && r <= 'z':
			return 'a' + (r-'a'+13)%26
		}
		return r
	}
	fmt.Printf("%s\n", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher...")))
	// Output: