buf.Truncate(26)
		check(t, "TestBasicOperations (7)", &buf, testString[0:26])

		buf.Truncate(20)
		check(t, "TestBasicOperations (8)", &buf, testString[0:20])

		empty(t, "TestBasicOperations (9)", &buf, testString[0:20], make([]byte, 5))
		empty(t, "TestBasicOperations (10)", &buf, "", make([]byte, 100))

		buf.WriteByte(testString[1])
		c, err := buf.ReadByte()

		}
	}
	return
}

// generatesZip64 reports whether f wrote a zip64 file.
// f is also responsible for closing w.
func generatesZip64(t *testing.T, f func(w *Writer)) bool {
	ss := &suffixSaver{keep: 10 << 20}
	w := NewWriter(ss)
	f(w)
	return suffixIsZip64(t, ss)
}

type sizedReaderAt interface {
	io.ReaderAt
	Size() int64
}

func suffixIsZip64(t *testing.T, zip sizedReaderAt) bool {

var sysStat func(fi fs.FileInfo, h *Header, doNameLookups bool) error

const (
	// Mode constants from the USTAR spec:
	// See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_06
	c_ISUID = 04000 // Set uid
	c_ISGID = 02000 // Set gid
	c_ISVTX = 01000 // Save text (sticky bit)

	// Common Unix mode constants; these are not defined in any common tar standard.

	names := []string{
		"0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/file.txt",
		"0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32/33/file.txt",
		"0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32/333/file.txt",
		"0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32/33/34/35/36/37/38/39/40/file.txt",