func (tr *Reader) readOldGNUSparseMap(hdr *Header, blk *block) (sparseDatas, error) {
	// Make sure that the input format is GNU.
	// Unfortunately, the STAR format also has a sparse header format that uses
	// the same type flag but has a completely different layout.
	if blk.getFormat() != FormatGNU {
		return nil, ErrHeader
	}
	hdr.Format.mayOnlyBe(FormatGNU)

	var p parser
	hdr.Size = p.parseNumeric(blk.toGNU().realSize())

		}
	}

	r := &Reader{
		args:       args,
		buf:        bufio.NewReaderSize(csvIn, csvSplitSize*2),
		readCloser: readCloser,
		close:      make(chan struct{}),
	}

	// Assume args are validated by ReaderArgs.UnmarshalXML()
	newCsvReader := func(r io.Reader) *csv.Reader {
		ret := csv.NewReader(r)
		ret.Comma = []rune(args.FieldDelimiter)[0]
		ret.Comment = []rune(args.CommentCharacter)[0]

		// calculations when dealing with legacy ZIP formats.
		if f.ModifiedTime != 0 || f.ModifiedDate != 0 {
			f.Modified = modified.In(timeZone(msdosModified.Sub(modified)))
		}
	}

	// Assume that uncompressed size 2³²-1 could plausibly happen in
	// an old zip32 file that was sharding inputs into the largest chunks
	// possible (or is just malicious; search the web for 42.zip).

// When size is >=0 it *must* match the amount of data provided by r.
//
// NewReader may try merge the given size, MD5 and SHA256 values
// into src - if src is a Reader - to avoid computing the same
// checksums multiple times.
// NewReader enforces S3 compatibility strictly by ensuring caller
// does not send more content than specified size.