Class iterator

lib/swoc/include/swoc/IPRange.h:1318–1376

   * @note Range merges are not triggered by modifications of the @a PAYLOAD via an iterator.
   */
  class iterator : public const_iterator {
    using self_type  = iterator;
    using super_type = const_iterator;

    friend class IPSpace;

  protected:
    using super_type::super_type; /// Inherit supertype constructors.
    /// Protected constructor to convert const to non-const.
    /// @note This makes for much less code duplication in iterator relevant methods.
    iterator(const_iterator const &that) : const_iterator(that) {}

  public:
    /// Value type of iteration.
    using value_type = detail::ip_space_value_type<PAYLOAD>;
    using pointer    = value_type *;
    using reference  = value_type &;

    /// Default constructor.
    iterator() = default;

    /// Copy constructor.
    iterator(self_type const &that) = default;

    /// Assignment.
    self_type &operator=(self_type const &that);

    /// Pre-increment.
    /// Move to the next element in the list.
    /// @return The iterator.
    self_type &operator++();

    /// Pre-decrement.
    /// Move to the previous element in the list.
    /// @return The iterator.
    self_type &operator--();

    /// Post-increment.
    /// Move to the next element in the list.
    /// @return The iterator value before the increment.
    self_type operator++(int);

    /// Post-decrement.
    /// Move to the previous element in the list.
    /// @return The iterator value before the decrement.
    self_type operator--(int);

    /// Dereference.
    /// @return A reference to the referent.
    reference operator*() const;

    /// Dereference.
    /// @return A pointer to the referent.
    pointer operator->() const;

  protected:
    // Retrieve the value and convert from the super (const) type value to the value for iterator.
    value_type &value() const;