end, baseOffset, err := readDirectoryEnd(rdr, size)
	if err != nil {
		return err
	}
	r.r = rdr
	r.baseOffset = baseOffset
	// Since the number of directory records is not validated, it is not
	// safe to preallocate r.File without first checking that the specified
	// number of files is reasonable, since a malformed archive may
	// indicate it contains up to 1 << 128 - 1 files. Since each file has a

		key, value, residual, err := parsePAXRecord(sbuf)
		if err != nil {
			return nil, ErrHeader
		}
		sbuf = residual

		switch key {
		case paxGNUSparseOffset, paxGNUSparseNumBytes:
			// Validate sparse header order and value.
			if (len(sparseMap)%2 == 0 && key != paxGNUSparseOffset) ||
				(len(sparseMap)%2 == 1 && key != paxGNUSparseNumBytes) ||
				strings.Contains(value, ",") {
				return nil, ErrHeader