// 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)
	}

	// If sp is non-nil, then this is a sparse file.
	// Note that it is possible for len(sp) == 0.
	if err == nil && spd != nil {

		v.input = v.input[copy(blk[:], v.input):]
		tr := Reader{r: bytes.NewReader(v.input)}
		got, err := tr.readOldGNUSparseMap(&hdr, &blk)
		if !slices.Equal(got, v.wantMap) {
			t.Errorf("test %d, readOldGNUSparseMap(): got %v, want %v", i, got, v.wantMap)
		}
		if err != v.wantErr {
			t.Errorf("test %d, readOldGNUSparseMap() = %v, want %v", i, err, v.wantErr)
		}
		if hdr.Size != v.wantSize {