}
	return
}

func (ss *suffixSaver) Suffix() []byte {
	if len(ss.buf) < ss.keep {
		return ss.buf
	}
	buf := make([]byte, ss.keep)
	n := copy(buf, ss.buf[ss.start:])
	copy(buf[n:], ss.buf[:])
	return buf
}

func (ss *suffixSaver) Write(p []byte) (n int, err error) {
	n = len(p)
	ss.size += int64(len(p))
	if len(ss.buf) < ss.keep {
		space := ss.keep - len(ss.buf)
		add := len(p)

}

func (f Format) String() string {
	var ss []string
	for f2 := Format(1); f2 < formatMax; f2 <<= 1 {
		if f.has(f2) {
			ss = append(ss, formatNames[f2])
		}
	}
	switch len(ss) {
	case 0:
		return "<unknown>"
	case 1:
		return ss[0]
	default:
		return "(" + strings.Join(ss, " | ") + ")"
	}
}

// Magics used to identify various formats.
const (

func TestReadTruncation(t *testing.T) {
	var ss []string
	for _, p := range []string{
		"testdata/gnu.tar",
		"testdata/ustar-file-reg.tar",
		"testdata/pax-path-hdr.tar",
		"testdata/sparse-formats.tar",
	} {
		buf, err := os.ReadFile(p)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		ss = append(ss, string(buf))
	}

	data1, data2, pax, sparse := ss[0], ss[1], ss[2], ss[3]

type headerError []string

func (he headerError) Error() string {
	const prefix = "archive/tar: cannot encode header"
	var ss []string
	for _, s := range he {
		if s != "" {
			ss = append(ss, s)
		}
	}
	if len(ss) == 0 {
		return prefix
	}
	return fmt.Sprintf("%s: %v", prefix, strings.Join(ss, "; and "))
}

// Type flags for Header.Typeflag.
const (
	// Type '0' indicates a regular file.
	TypeReg = '0'

		uniqueA  = "-  "
		uniqueB  = "+  "
		identity = "   "
	)
	var ss []string
	sa := strings.Split(strings.TrimSpace(hex.Dump(a)), "\n")
	sb := strings.Split(strings.TrimSpace(hex.Dump(b)), "\n")
	for len(sa) > 0 && len(sb) > 0 {
		if sa[0] == sb[0] {
			ss = append(ss, identity+sa[0])
		} else {
			ss = append(ss, uniqueA+sa[0])
			ss = append(ss, uniqueB+sb[0])
		}
		sa, sb = sa[1:], sb[1:]
	}
	for len(sa) > 0 {