/*
		// Write the sparse map and setup the sparse writer if necessary.
		if len(spd) > 0 {
			// Use tw.curr since the sparse map is accounted for in hdr.Size.
			if _, err := tw.curr.Write(spb); err != nil {
				return err
			}
			tw.curr = &sparseFileWriter{tw.curr, spd, 0}
		}
	*/
	return nil
}

func (tw *Writer) writeGNUHeader(hdr *Header) error {

	CRANDN CR0GT, CR0EQ, CR0SO      // 4c620902
	CREQV CR0GT, CR0EQ, CR0SO       // 4c620a42
	CRNAND CR0GT, CR0EQ, CR0SO      // 4c6209c2
	CRNOR CR0GT, CR0EQ, CR0SO       // 4c620842
	CROR CR0GT, CR0EQ, CR0SO        // 4c620b82
	CRORN CR0GT, CR0EQ, CR0SO       // 4c620b42
	CRXOR CR0GT, CR0EQ, CR0SO       // 4c620982

	ISEL $0, R3, R4, R5             // 7ca3201e
	ISEL $1, R3, R4, R5             // 7ca3205e

			}
			return spd
		}(),
	}}

	for i, v := range vectors {
		var hdr Header
		hdr.PAXRecords = v.inputHdrs
		r := strings.NewReader(v.inputData + "#") // Add canary byte
		tr := Reader{curr: &regFileReader{r, int64(r.Len())}}
		got, err := tr.readGNUSparsePAXHeaders(&hdr)
		if !equalSparseEntries(got, v.wantMap) {
			t.Errorf("test %d, readGNUSparsePAXHeaders(): got %v, want %v", i, got, v.wantMap)
		}

	if isHeaderOnlyType(hdr.Typeflag) {
		nb = 0
	}
	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