} else {
		i++
	}
	return s[0:i]
}

// TrimFunc returns a subslice of s by slicing off all leading and trailing
// UTF-8-encoded code points c that satisfy f(c).
func TrimFunc(s []byte, f func(r rune) bool) []byte {
	return TrimRightFunc(TrimLeftFunc(s, f), f)
}

// TrimPrefix returns s without the provided leading prefix string.
// If s doesn't start with prefix, s is returned unchanged.

// never return an empty string. The definition of space is set by
// unicode.IsSpace.
func ScanWords(data []byte, atEOF bool) (advance int, token []byte, err error) {
	// Skip leading spaces.
	start := 0
	for width := 0; start < len(data); start += width {
		var r rune
		r, width = utf8.DecodeRune(data[start:])
		if !isSpace(r) {
			break
		}
	}

	f.err = ErrFieldTooLong
}

func (p *parser) parseOctal(b []byte) int64 {
	// Because unused fields are filled with NULs, we need
	// to skip leading NULs. Fields may also be padded with
	// spaces or NULs.
	// So we remove leading and trailing NULs and spaces to
	// be sure.
	b = bytes.Trim(b, " \x00")

	if len(b) == 0 {
		return 0
	}
	x, perr := strconv.ParseUint(p.parseString(b), 8, 64)

	return xdir < ydir || xdir == ydir && xelem < yelem
}

// Open opens the named file in the ZIP archive,
// using the semantics of fs.FS.Open:
// paths are always slash separated, with no
// leading / or ../ elements.
func (r *Reader) Open(name string) (fs.File, error) {
	r.initFileList()

	if !fs.ValidPath(name) {
		return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrInvalid}
	}

	"cmd/internal/obj/riscv"
	"cmd/internal/obj/s390x"
	"cmd/internal/obj/wasm"
	"cmd/internal/obj/x86"
	"fmt"
	"strings"
)

// Pseudo-registers whose names are the constant name without the leading R.
const (
	RFP = -(iota + 1)
	RSB
	RSP
	RPC
)

// Arch wraps the link architecture object with more architecture-specific information.
type Arch struct {
	*obj.LinkArch

	f.walk(ast1, ctxProg, (*File).saveExport)
	f.walk(ast2, ctxProg, (*File).saveExport2)

	f.Comments = ast1.Comments
	f.AST = ast2
}

// Like ast.CommentGroup's Text method but preserves
// leading blank lines, so that line numbers line up.
func commentText(g *ast.CommentGroup) string {
	var pieces []string
	for _, com := range g.List {
		c := com.Text
		// Remove comment markers.

		// Some systems use leading _ to denote non-assembly symbols.
		return s == "__cgodebug_ints" || s == "___cgodebug_ints"
	}
	isDebugFloats := func(s string) bool {
		// Some systems use leading _ to denote non-assembly symbols.
		return s == "__cgodebug_floats" || s == "___cgodebug_floats"
	}
	indexOfDebugStr := func(s string) int {
		// Some systems use leading _ to denote non-assembly symbols.

// It returns a [Writer] to which the file contents should be written.
// The file contents will be compressed using the [Deflate] method.
// The name must be a relative path: it must not start with a drive
// letter (e.g. C:) or leading slash, and only forward slashes are
// allowed. To create a directory instead of a file, add a trailing
// slash to the name.
// The file's contents must be written to the [io.Writer] before the next