Class iterator

example/cacheHierarchy/fkYAML/node.hpp:9983–10285

/// @tparam ValueType The type of iterated elements.
template <typename ValueType>
class iterator {
    /// @brief The iterator type with ValueType of different const-ness.
    using other_iterator_type = typename std::conditional<
        std::is_const<ValueType>::value, iterator<typename std::remove_const<ValueType>::type>,
        iterator<const ValueType>>::type;

    friend other_iterator_type;

public:
    /// A type for iterator traits of instantiated @Iterator template class.
    using iterator_traits_type = iterator_traits<ValueType>;

    /// A type for iterator category tag.
    using iterator_category = std::bidirectional_iterator_tag;
    /// A type of iterated element.
    using value_type = typename iterator_traits_type::value_type;
    /// A type to represent differences between iterators.
    using difference_type = typename iterator_traits_type::difference_type;
    /// A type of an element pointer.
    using pointer = typename iterator_traits_type::pointer;
    /// A type of reference to an element.
    using reference = typename iterator_traits_type::reference;

    static_assert(is_basic_node<value_type>::value, "iterator class only accepts a basic_node as its value type.");

    /// @brief Constructs an iterator object.
    iterator() = default;

    /// @brief Construct a new iterator object with sequence iterator object.
    /// @param[in] itr An sequence iterator object.
    iterator(const typename value_type::sequence_type::iterator& itr) noexcept {
        m_iterator_holder.sequence_iterator = itr;
    }

    /// @brief Construct a new iterator object with mapping iterator object.
    /// @param[in] itr An mapping iterator object.
    iterator(const typename value_type::mapping_type::iterator& itr) noexcept
        : m_inner_iterator_type(iterator_t::MAPPING) {
        m_iterator_holder.mapping_iterator = itr;
    }

    /// @brief Copy constructs an iterator.
    iterator(const iterator&) = default;

    /// @brief Copy constructs an iterator from another iterator with different const-ness in ValueType.
    /// @note This copy constructor is not defined if ValueType is not const to avoid const removal from ValueType.
    /// @tparam OtherIterator The iterator type to copy from.
    /// @param other An iterator to copy from with different const-ness in ValueType.
    template <
        typename OtherIterator,
        enable_if_t<
            conjunction<std::is_same<OtherIterator, other_iterator_type>, std::is_const<ValueType>>::value, int> = 0>
    iterator(const OtherIterator& other) noexcept
        : m_inner_iterator_type(other.m_inner_iterator_type),
          m_iterator_holder(other.m_iterator_holder) {
    }

    /// @brief A copy assignment operator of the iterator class.