f.formatNumeric(sa.Entry(i).Offset(), sp[0].Offset)
					f.formatNumeric(sa.Entry(i).Length(), sp[0].Length)
					sp = sp[1:]
				}
				if len(sp) > 0 {
					sa.IsExtended()[0] = 1
				}
				return sp
			}
			sp2 := formatSPD(spd, blk.GNU().Sparse())
			for len(sp2) > 0 {
				var spHdr block
				sp2 = formatSPD(sp2, spHdr.Sparse())
				spb = append(spb, spHdr[:]...)

	populateSparseMap := func(sa sparseArray, sps []string) []string {
		for i := 0; len(sps) > 0 && i < sa.maxEntries(); i++ {
			copy(sa.entry(i), sps[0])
			sps = sps[1:]
		}
		if len(sps) > 0 {
			copy(sa.isExtended(), "\x80")
		}
		return sps
	}

	makeInput := func(format Format, size string, sps ...string) (out []byte) {
		// Write the initial GNU header.
		var blk block
		gnu := blk.toGNU()