n, err := strconv.ParseInt(size, 10, 64)
		if err != nil {
			return nil, ErrHeader
		}
		hdr.Size = n
	}

	// Read the sparse map according to the appropriate format.
	if is1x0 {
		return readGNUSparseMap1x0(tr.curr)
	}
	return readGNUSparseMap0x1(hdr.PAXRecords)
}

// mergePAX merges paxHdrs into hdr for all relevant fields of Header.
func mergePAX(hdr *Header, paxHdrs map[string]string) (err error) {