if nb < 0 {
		return ErrHeader
	}

	tr.pad = blockPadding(nb)
	tr.curr = &regFileReader{r: tr.r, nb: nb}
	return nil
}

// 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 {