Method fill

ruby/red-arrow/ext/arrow/memory-view.cpp:206–214

      private:
      void fill(const arrow::Array& array) {
        const auto array_data = array.data();
        const auto data = array_data->GetValuesSafe<uint8_t>(1);
        view_->data = const_cast<void *>(reinterpret_cast<const void *>(data));
        const auto type =
          std::static_pointer_cast<const arrow::FixedWidthType>(array.type());
        view_->item_size = type->bit_width() / 8;
        view_->byte_size = view_->item_size * array.length();
      }

      memory_view *view_;
    };