slide_view_iterator.cpp

#include <boost/iterator/iterator_adaptor.hpp>
#include <boost/utility.hpp>

namespace canard {
	template <class Iterator>
	class slide_view_iterator;

	namespace detail {
		template <class Iterator>
		struct slide_iterator_base {
			typedef boost::iterator_adaptor<
				slide_view_iterator<Iterator>
			  , Iterator
			> type;
		};
		
	} // namespace detail

	template <class Iterator>
	class slide_view_iterator
		: public detail::slide_iterator_base<Iterator>::type
	{
		typedef typename detail::slide_iterator_base<
			Iterator
		>::type super_t;

		friend class boost::iterator_core_access;

	public:
		typedef typename std::iterator_traits<Iterator>::difference_type difference_type;
		typedef Iterator base_iterator;

		slide_view_iterator() {}

		slide_view_iterator(base_iterator iter, difference_type n = 0)
			: super_t(boost::next(iter, n))
			, m_iterator(iter)
		{
		}

		base_iterator const& base() const
		{
			return m_iterator;
		}

	private:
		void advance(difference_type n)
		{
			std::advance(m_iterator, n);
			std::advance(this->base_reference(), n);
		}

		void increment()
		{
			++m_iterator;
			++(this->base_reference());
		}

		void decrement()
		{
			--m_iterator;
			--(this->base_reference());
		}

		base_iterator m_iterator;
	};

	template <class Iterator, class Difference = typename std::iterator_traits<Iterator>::difference_type>
	slide_view_iterator<Iterator>
	make_slide_view_iterator(Iterator iter, Difference n = 0)
	{
		return slide_view_iterator<Iterator>(iter, n);
	}
} // namespace canard