def reverse_byte_nibbles!
    w = ""
    w.force_encoding("BINARY") if w.respond_to?(:force_encoding)
    @bytes.each_byte do |b|
      w << ((b >> 4)|((b&0xF)<<4))
    end
    @bytes = w
    __setobj__ @bytes
    self
  end
def reverse_byte_nibbles!
    w = ""
    w.force_encoding("BINARY") if w.respond_to?(:force_encoding)
    @bytes.each_byte do |b|
      w << ((b >> 4)|((b&0xF)<<4))
    end
    @bytes = w
    __setobj__ @bytes
    self
  end
Reverse the order of the nibbles in each byte.