module BinData::FloatingPoint

def create_num_bytes_code(precision)
  (precision == :single) ? 4 : 8
end

def create_read_code(precision, endian)
  if precision == :single
    unpack = (endian == :little) ? 'e' : 'g'
    nbytes = 4
  else # double_precision
    unpack = (endian == :little) ? 'E' : 'G'
    nbytes = 8
  end
  "io.readbytes(#{nbytes}).unpack('#{unpack}').at(0)"
end

def create_to_binary_s_code(precision, endian)
  if precision == :single
    pack = (endian == :little) ? 'e' : 'g'
  else # double_precision
    pack = (endian == :little) ? 'E' : 'G'
  end
  "[val].pack('#{pack}')"
end

def define_methods(float_class, precision, endian)
  float_class.module_eval <<-END
    def do_num_bytes
      #{create_num_bytes_code(precision)}
    end
    #---------------
    private
    def sensible_default
      0.0
    end
    def value_to_binary_string(val)
      #{create_to_binary_s_code(precision, endian)}
    end
    def read_and_return_value(io)
      #{create_read_code(precision, endian)}
    end
  END
end