func TestEqualNearPageBoundary(t *testing.T) {
	t.Parallel()
	b := dangerousSlice(t)
	for i := range b {
		b[i] = 'A'
	}
	for i := 0; i <= len(b); i++ {
		Equal(b[:i], b[len(b)-i:])
		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 {

			{8, "\x00G\x00o\x00G\x00o"},
			{4, "end\n"},
		},
	}}

	for _, v := range vectors {
		t.Run(path.Base(v.file), func(t *testing.T) {
			f, err := os.Open(v.file)
			if err != nil {
				t.Fatalf("Open() error: %v", err)
			}
			defer f.Close()

			tr := NewReader(f)
			for i, tc := range v.cases {
				hdr, err := tr.Next()
				if err != nil || hdr == nil {

	fs, err := os.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
	if err != nil {
		return fmt.Errorf("unable to find %d tasks: %v", pid, err)
	}
	expectedProc := fmt.Sprintf("Pid:\t%d", pid)
	foundAThread := false
	for _, f := range fs {
		tf := fmt.Sprintf("/proc/%s/status", f.Name())
		d, err := os.ReadFile(tf)
		if err != nil {
			// There are a surprising number of ways this
			// can error out on linux.  We've seen all of

func isASCII(s string) bool {
	for _, c := range s {
		if c >= 0x80 || c == 0x00 {
			return false
		}
	}
	return true
}

// toASCII converts the input to an ASCII C-style string.
// This is a best effort conversion, so invalid characters are dropped.
func toASCII(s string) string {
	if isASCII(s) {
		return s
	}
	b := make([]byte, 0, len(s))
	for _, c := range s {
		if c < 0x80 && c != 0x00 {

	if err != nil {
		if os.IsNotExist(err) {
			t.Skip("no /proc/self/exe")
		}
		t.Fatal("opening /proc/self/exe: ", err)
	}
	defer f.Close()

	c := 0
sections:
	for i, s := range f.Sections {
		if s.Type != elf.SHT_NOTE {
			continue
		}

		d, err := s.Data()
		if err != nil {
			t.Logf("reading data of note section %d: %v", i, err)
			continue
		}

		for len(d) > 0 {

		// If we were unable to read anything out of the archive don't
		// bother trying to roundtrip it.
		if len(files) == 0 {
			return
		}

		out := bytes.NewBuffer(nil)
		w := NewWriter(out)
		for _, f := range files {
			if err := w.WriteHeader(f.header); err != nil {
				t.Fatalf("unable to write previously parsed header: %s", err)
			}
			if _, err := w.Write(f.content); err != nil {

	{"\xff-\xff", "-", -1, []string{"\xff", "\xff"}},
}

func TestSplit(t *testing.T) {
	for _, tt := range splittests {
		a := SplitN([]byte(tt.s), []byte(tt.sep), tt.n)

		// Appending to the results should not change future results.
		var x []byte
		for _, v := range a {
			x = append(v, 'z')
		}

		result := sliceOfString(a)
		if !eq(result, tt.a) {

# update CODE and DATA below, and then run
#
#	./update.bash -commit
#
# That will prepare the files and create the commit.
#
# To review such a commit (as the reviewer), use:
#
#	git codereview change NNNNNN   # CL number
#	cd lib/time
#	./update.bash
#
# If it prints "No updates needed.", then the generated files
# in the CL match the update.bash in the CL.

# Versions to use.
CODE=2024a
DATA=2024a

	cond = strings.TrimPrefix(cond, ".")
	if cond == "" {
		return arm.C_SCOND_NONE, true
	}
	names := strings.Split(cond, ".")
	bits := uint8(0)
	for _, name := range names {
		if b, present := ls[name]; present {
			bits |= b
			continue
		}
		if b, present := scond[name]; present {
			bits = (bits &^ arm.C_SCOND) | b
			continue
		}
		return 0, false
	}

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