wantMap:  sparseDatas{{0, 1}, {2, 1}, {4, 1}, {6, 1}},
		wantSize: 03333,
	}, {
		input: makeInput(FormatGNU, "",
			append(append(
				makeSparseStrings(sparseDatas{{0, 1}, {2, 1}}),
				[]string{"", ""}...),
				makeSparseStrings(sparseDatas{{4, 1}, {6, 1}})...)...),
		wantMap: sparseDatas{{0, 1}, {2, 1}, {4, 1}, {6, 1}},
	}, {

}

// handleSparseFile checks if the current file is a sparse format of any type
// and sets the curr reader appropriately.
func (tr *Reader) handleSparseFile(hdr *Header, rawHdr *block) error {
	var spd sparseDatas
	var err error
	if hdr.Typeflag == TypeGNUSparse {
		spd, err = tr.readOldGNUSparseMap(hdr, rawHdr)
	} else {
		spd, err = tr.readGNUSparsePAXHeaders(hdr)
	}

// deals with sparseDatas.
//
// However, the external API uses sparseHoles instead of sparseDatas because the
// zero value of sparseHoles logically represents a normal file (i.e., there are
// no holes in it). On the other hand, the zero value of sparseDatas implies
// that the file has no data in it, which is rather odd.
//