taichi-ishitani/rggen

simple_item :register, :offset_address do
  register_map do
    field :start_address
    field :end_address
    field :byte_size do
      end_address - start_address + 1
    end
    field :single? do
      byte_size == configuration.byte_width
    end
    field :multiple? do
      byte_size > configuration.byte_width
    end

    input_pattern %r{(#{number})(?:-(#{number}))?}

    build do |cell|
      @start_address, @end_address  = parse_address(cell)
      check_start_end_adderss_relation(cell)
      check_address_align(cell)
      check_address_range(cell)
    end

    def parse_address(cell)
      if pattern_matched?
        addresses = captures.compact.map(&method(:Integer))
        if addresses.size == 2
          addresses
        else
          [addresses[0], addresses[0] + configuration.byte_width - 1]
        end
      else
        error "invalid value for offset address: #{cell.inspect}"
      end
    end

    def check_start_end_adderss_relation(cell)
      return if start_address < end_address
      return if [configuration.byte_width, byte_size].all? { |v| v == 1 }
      error "start address is equal to or greater than end address: #{cell}"
    end

    def check_address_align(cell)
      return if [start_address, end_address + 1].all? do |a|
        a.multiple?(configuration.byte_width)
      end
      error 'not aligned with data width' \
            "(#{configuration.data_width}): #{cell}"
    end

    def check_address_range(cell)
      return if end_address <= max_address
      error 'exceeds the maximum offset address' \
            "(0x#{max_address.to_s(16)}): #{cell}"
    end

    def max_address
      register_block.byte_size - 1
    end
  end
end