t.Errorf("buf = %q; want foo", buf)
	}

	r.Reset(strings.NewReader("bar bar"))
	checkAll(r, "bar bar")

	*r = Reader{} // zero out the Reader
	r.Reset(strings.NewReader("bar bar"))
	checkAll(r, "bar bar")

	// Wrap a reader and then Reset to that reader.
	r.Reset(strings.NewReader("recur"))
	r2 := NewReader(r)
	checkAll(r2, "recur")
	r.Reset(strings.NewReader("recur2"))
	r2.Reset(r)

		if got != v.want {
			t.Errorf("formatPAXTime(%ds, %dns): got %q, want %q",
				v.sec, v.nsec, got, v.want)
		}
	}
}

func TestParsePAXRecord(t *testing.T) {
	medName := strings.Repeat("CD", 50)
	longName := strings.Repeat("AB", 100)

	vectors := []struct {
		in      string
		wantRes string
		wantKey string
		wantVal string
		ok      bool
	}{
		{"6 k=v\n\n", "\n", "k", "v", true},

func TestRepeat(t *testing.T) {
	for _, tt := range RepeatTests {
		tin := []byte(tt.in)
		tout := []byte(tt.out)
		a := Repeat(tin, tt.count)
		if !Equal(a, tout) {
			t.Errorf("Repeat(%q, %d) = %q; want %q", tin, tt.count, a, tout)
			continue
		}
	}
}

func repeat(b []byte, count int) (err error) {
	defer func() {
		if r := recover(); r != nil {
			switch v := r.(type) {
			case error:

		return part.off+part.n > off
	})
	parts := r.buf[skipParts:]
	if len(parts) > 0 {
		skipBytes := off - parts[0].off
		for _, part := range parts {
			repeat := int(min(part.n-skipBytes, int64(len(p)-n)))
			memset(p[n:n+repeat], part.b)
			n += repeat
			if n == len(p) {
				return
			}
			skipBytes = 0
		}
	}
	if n != len(p) {
		err = io.ErrUnexpectedEOF
	}
	return
}

The [Repeat] function returns a new slice that repeats the

	bigBuf := bytes.Repeat([]byte("a"), 1<<20)

	runOnce := func(buf *bytes.Buffer) {
		buf.Reset()
		zw := NewWriter(buf)
		for j := 0; j < 3; j++ {
			w, _ := zw.CreateHeader(&FileHeader{
				Name:   "foo",
				Method: Deflate,
			})
			w.Write(bigBuf)
		}
		zw.Close()
	}

	b.ReportAllocs()
	// Run once and then reset the timer.

						int64(1e10 - blockSize),
						strings.Repeat("\x00", blockSize-100) + strings.Repeat("0123456789", 10),
						int64(1e10 - blockSize),
						strings.Repeat("\x00", blockSize-100) + strings.Repeat("0123456789", 10),
						int64(1e10 - blockSize),
						strings.Repeat("\x00", blockSize-100) + strings.Repeat("0123456789", 10),
						int64(1e10 - blockSize),
						strings.Repeat("\x00", blockSize-100) + strings.Repeat("0123456789", 10),

		inputHdrs: map[string]string{paxGNUSparseMajor: "1", paxGNUSparseMinor: "0"},
		wantErr:   ErrHeader,
	}, {
		inputData: padInput(strings.Repeat("0", 300) + "1\n" + strings.Repeat("0", 1000) + "5\n" + strings.Repeat("0", 800) + "2\n"),
		inputHdrs: map[string]string{paxGNUSparseMajor: "1", paxGNUSparseMinor: "0"},
		wantMap:   sparseDatas{{5, 2}},
	}, {
		inputData: padInput("2\n10737418240\n512\n21474836480\n512\n"),

// record is formatted as:
//
//	"%d %s=%s\n" % (size, key, value)
//
// Keys and values should be UTF-8, but the number of bad writers out there
// forces us to be a more liberal.
// Thus, we only reject all keys with NUL, and only reject NULs in values
// for the PAX version of the USTAR string fields.
// The key must not contain an '=' character.
func validPAXRecord(k, v string) bool {
	if k == "" || strings.Contains(k, "=") {

	for _, growLen := range []int{0, 100, 1000, 10000, 100000} {
		for _, startLen := range []int{0, 100, 1000, 10000, 100000} {
			xBytes := Repeat(x, startLen)

			buf := NewBuffer(xBytes)
			// If we read, this affects buf.off, which is good to test.
			readBytes, _ := buf.Read(tmp)
			yBytes := Repeat(y, growLen)
			allocs := testing.AllocsPerRun(100, func() {
				buf.Grow(growLen)
				buf.Write(yBytes)
			})