// 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 {