if s.err != nil {
			// Shut it down.
			s.start = 0
			s.end = 0
			return false
		}
		// Must read more data.
		// First, shift data to beginning of buffer if there's lots of empty space
		// or space is needed.
		if s.start > 0 && (s.end == len(s.buf) || s.start > len(s.buf)/2) {
			copy(s.buf, s.buf[s.start:s.end])
			s.end -= s.start
			s.start = 0
		}
		// Is the buffer full? If so, resize.

	{"4611686018427387904", 4611686018427387904, true},
}

func TestExpr(t *testing.T) {
	p := NewParser(nil, nil, nil) // Expression evaluation uses none of these fields of the parser.
	for i, test := range exprTests {
		p.start(lex.Tokenize(test.input))
		result := int64(p.expr())
		if result != test.output {
			t.Errorf("%d: %q evaluated to %d; expected %d", i, test.input, result, test.output)
		}
		tok := p.next()

	d.dirDiskNbr = b.uint32()         // number of the disk with the start of the central directory
	d.dirRecordsThisDisk = b.uint64() // total number of entries in the central directory on this disk
	d.directoryRecords = b.uint64()   // total number of entries in the central directory
	d.directorySize = b.uint64()      // size of the central directory
	d.directoryOffset = b.uint64()    // offset of start of central directory with respect to the starting disk number

// See the [ZIP specification] for details.
//
// [ZIP specification]: https://support.pkware.com/pkzip/appnote
type FileHeader struct {
	// Name is the name of the file.
	//
	// It must be a relative path, not start with a drive letter (such as "C:"),
	// and must use forward slashes instead of back slashes. A trailing slash
	// indicates that this file is a directory and should have no data.
	Name string

func TestIndexByteBig(t *testing.T) {
	var n = 1024
	if testing.Short() {
		n = 128
	}
	b := make([]byte, n)
	for i := 0; i < n; i++ {
		// different start alignments
		b1 := b[i:]
		for j := 0; j < len(b1); j++ {
			b1[j] = 'x'
			pos := IndexByte(b1, 'x')
			if pos != j {
				t.Errorf("IndexByte(%q, 'x') = %v", b1, pos)
			}
			b1[j] = 0

	// more efficient, possibly due to cache effects.
	start := -1 // valid span start if >= 0
	for i := 0; i < len(s); {
		size := 1
		r := rune(s[i])
		if r >= utf8.RuneSelf {
			r, size = utf8.DecodeRune(s[i:])
		}
		if f(r) {
			if start >= 0 {
				spans = append(spans, span{start, i})
				start = -1
			}
		} else {
			if start < 0 {
				start = i
			}
		}
		i += size
	}

		add := len(p)
		if add > space {
			add = space
		}
		ss.buf = append(ss.buf, p[:add]...)
		p = p[add:]
	}
	for len(p) > 0 {
		n := copy(ss.buf[ss.start:], p)
		p = p[n:]
		ss.start += n
		if ss.start == ss.keep {
			ss.start = 0
		}
	}
	return
}

// generatesZip64 reports whether f wrote a zip64 file.
// f is also responsible for closing w.

	for _, op := range operands {
		p.start(op)
		if name, abi, ok := p.funcAddress(); ok {
			fmt.Fprintf(w, "ref %s %s\n", name, abi)
		}
	}
}

func (p *Parser) start(operand []lex.Token) {
	p.input = operand
	p.inputPos = 0
}

// address parses the operand into a link address structure.
func (p *Parser) address(operand []lex.Token) obj.Addr {
	p.start(operand)
	addr := obj.Addr{}

	// We have a '#'; it must be followed by a known word (define, include, etc.).
	tok := in.Stack.Next()
	if tok != scanner.Ident {
		in.expectText("expected identifier after '#'")
	}
	if !in.enabled() {
		// Can only start including again if we are at #else or #endif but also
		// need to keep track of nested #if[n]defs.
		// We let #line through because it might affect errors.
		switch in.Stack.Text() {

	for n := attempts; n > 0; n-- {
		cmd := exec.Command(os.Args[0], args...)
		cmd.Env = append(os.Environ(), "test18146=exec")
		buf := bytes.NewBuffer(nil)
		cmd.Stdout = buf
		cmd.Stderr = buf
		if err := cmd.Start(); err != nil {
			// We are starting so many processes that on
			// some systems (problem seen on Darwin,
			// Dragonfly, OpenBSD) the fork call will fail
			// with EAGAIN.
			if pe, ok := err.(*os.PathError); ok {