verifyString(h.Uname, len(ustar.userName()), "Uname", paxUname)
	verifyString(h.Gname, len(ustar.groupName()), "Gname", paxGname)
	verifyNumeric(h.Mode, len(v7.mode()), "Mode", paxNone)
	verifyNumeric(int64(h.Uid), len(v7.uid()), "Uid", paxUid)
	verifyNumeric(int64(h.Gid), len(v7.gid()), "Gid", paxGid)
	verifyNumeric(h.Size, len(v7.size()), "Size", paxSize)
	verifyNumeric(h.Devmajor, len(ustar.devMajor()), "Devmajor", paxNone)

	sysStat = statUnix
}

// userMap and groupMap caches UID and GID lookups for performance reasons.
// The downside is that renaming uname or gname by the OS never takes effect.
var userMap, groupMap sync.Map // map[int]string

func statUnix(fi fs.FileInfo, h *Header, doNameLookups bool) error {
	sys, ok := fi.Sys().(*syscall.Stat_t)
	if !ok {
		return nil
	}
	h.Uid = int(sys.Uid)
	h.Gid = int(sys.Gid)
	if doNameLookups {

			t.Errorf("i=%d: Name: got %v, want %v", i, got, want)
		}
		if got, want := h2.Size, v.h.Size; got != want {
			t.Errorf("i=%d: Size: got %v, want %v", i, got, want)
		}
		if got, want := h2.Uid, v.h.Uid; got != want {
			t.Errorf("i=%d: Uid: got %d, want %d", i, got, want)
		}
		if got, want := h2.Gid, v.h.Gid; got != want {
			t.Errorf("i=%d: Gid: got %d, want %d", i, got, want)
		}

				Size:     5,
				Mode:     0640,
				Uid:      73025,
				Gid:      5000,
				Uname:    "dsymonds",
				Gname:    "eng",
				ModTime:  time.Unix(1246508266, 0),
			}, nil},
			testWrite{"Kilts", 5, nil},

			testHeader{Header{
				Typeflag: TypeReg,
				Name:     "small2.txt",
				Size:     11,
				Mode:     0640,
				Uid:      73025,
				Uname:    "dsymonds",
				Gname:    "eng",

	hdr.Typeflag = v7.typeFlag()[0]
	hdr.Name = p.parseString(v7.name())
	hdr.Linkname = p.parseString(v7.linkName())
	hdr.Size = p.parseNumeric(v7.size())
	hdr.Mode = p.parseNumeric(v7.mode())
	hdr.Uid = int(p.parseNumeric(v7.uid()))
	hdr.Gid = int(p.parseNumeric(v7.gid()))
	hdr.ModTime = time.Unix(p.parseNumeric(v7.modTime()), 0)

	// Unpack format specific fields.
	if format > formatV7 {
		ustar := tr.blk.toUSTAR()