rbr1, err := r.makeReverseBitReader(data, off1, start1-2)
	if err != nil {
		return nil, err
	}

	rbr2, err := r.makeReverseBitReader(data, off2, start2-2)
	if err != nil {
		return nil, err
	}

	rbr3, err := r.makeReverseBitReader(data, off3, start3-2)
	if err != nil {
		return nil, err
	}

	rbr4, err := r.makeReverseBitReader(data, off4, start4-2)
	if err != nil {

	bits  uint32  // bits ready to be returned
	cnt   uint32  // number of valid bits in bits field
}

// makeReverseBitReader makes a reverseBitReader reading backward
// from off to start. The bitstream starts with a 1 bit in the last
// byte, at off.
func (r *Reader) makeReverseBitReader(data block, off, start int) (reverseBitReader, error) {
	streamStart := data[off]
	if streamStart == 0 {

		if err != nil {
			return 0, 0, err
		}
		fseTable := r.fseScratch

		if off+int(hdr) > len(data) {
			return 0, 0, r.makeEOFError(off)
		}

		rbr, err := r.makeReverseBitReader(data, off+int(hdr)-1, noff)
		if err != nil {
			return 0, 0, err
		}

		state1, err := rbr.val(uint8(fseBits))
		if err != nil {
			return 0, 0, err
		}

		state2, err := rbr.val(uint8(fseBits))

func (r *Reader) execSeqs(data block, off int, litbuf []byte, seqCount int) error {
	// Set up the initial states for the sequence code readers.

	rbr, err := r.makeReverseBitReader(data, len(data)-1, off)
	if err != nil {
		return err
	}

	literalState, err := rbr.val(r.seqTableBits[seqLiteral])
	if err != nil {
		return err
	}