class BinData::IO

def write_little_endian_bits(val, nbits)
  while nbits > 0
    bits_req = 8 - @wnbits
    if nbits >= bits_req
      lsb_bits = val & mask(bits_req)
      nbits -= bits_req
      val >>= bits_req
      @wval   = @wval | (lsb_bits << @wnbits)
      @raw_io.write(@wval.chr)
      @wval   = 0
      @wnbits = 0
    else
      @wval   = @wval | (val << @wnbits)
      @wnbits += nbits
      nbits = 0
    end
  end
end