var f formatter
		got := make([]byte, len(v.want))
		f.formatNumeric(got, v.in)
		ok := (f.err == nil)
		if ok != v.ok {
			if v.ok {
				t.Errorf("formatNumeric(%d): got formatting failure, want success", v.in)
			} else {
				t.Errorf("formatNumeric(%d): got formatting success, want failure", v.in)
			}
		}
		if string(got) != v.want {
			t.Errorf("formatNumeric(%d): got %q, want %q", v.in, got, v.want)
		}
	}
}

	var spd sparseDatas
	var spb []byte
	blk := tw.templateV7Plus(hdr, f.formatString, f.formatNumeric)
	if !hdr.AccessTime.IsZero() {
		f.formatNumeric(blk.toGNU().accessTime(), hdr.AccessTime.Unix())
	}
	if !hdr.ChangeTime.IsZero() {
		f.formatNumeric(blk.toGNU().changeTime(), hdr.ChangeTime.Unix())
	}
	// TODO(dsnet): Re-enable this when adding sparse support.

		}
		return int64(x)
	}

	// Normal case is base-8 (octal) format.
	return p.parseOctal(b)
}

// formatNumeric encodes x into b using base-8 (octal) encoding if possible.
// Otherwise it will attempt to use base-256 (binary) encoding.
func (f *formatter) formatNumeric(b []byte, x int64) {
	if fitsInOctal(len(b), x) {
		f.formatOctal(b, x)
		return
	}

	if fitsInBase256(len(b), x) {

		}
		return out
	}

	makeSparseStrings := func(sp []sparseEntry) (out []string) {
		var f formatter
		for _, s := range sp {
			var b [24]byte
			f.formatNumeric(b[:12], s.Offset)
			f.formatNumeric(b[12:], s.Length)
			out = append(out, string(b[:]))
		}
		return out
	}

	vectors := []struct {
		input    []byte
		wantMap  sparseDatas
		wantSize int64