//

 //=======================================================================

 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.

 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek

 //

 // Distributed under the Boost Software License, Version 1.0. (See

 // accompanying file LICENSE_1_0.txt or copy at

 // http://www.boost.org/LICENSE_1_0.txt)

 //=======================================================================

 //

 #ifndef BOOST_GRAPH_DETAIL_INCIDENCE_ITERATOR_HPP

 #define BOOST_GRAPH_DETAIL_INCIDENCE_ITERATOR_HPP

 #include <utility>

 #include <iterator>

 // OBSOLETE

 namespace boost {

   namespace detail {

     // EdgeDir tags

     struct in_edge_tag { };

     struct out_edge_tag { };

     template <class Vertex, class Edge, class Iterator1D, class EdgeDir>

     struct bidir_incidence_iterator {

       typedef bidir_incidence_iterator self;

       typedef Edge edge_type;

       typedef typename Edge::property_type EdgeProperty;

     public:

       typedef int difference_type;

       typedef std::forward_iterator_tag iterator_category;

       typedef edge_type reference;

       typedef edge_type value_type;

       typedef value_type* pointer;

       inline bidir_incidence_iterator() {}

       inline bidir_incidence_iterator(Iterator1D ii, Vertex src) 

         : i(ii), _src(src) { }

       inline self& operator++() { ++i; return *this; }

       inline self operator++(int) { self tmp = *this; ++(*this); return tmp; }

       inline reference operator*() const {

         return deref_helper(EdgeDir());

       }

       inline self* operator->() { return this; }

       Iterator1D& iter() { return i; }

       const Iterator1D& iter() const { return i; }

       Iterator1D i;

       Vertex _src;

     protected:

       inline reference deref_helper(out_edge_tag) const {

         return edge_type( _src, (*i).get_target(), &(*i).get_property() );

       }

       inline reference deref_helper(in_edge_tag) const {

         return edge_type((*i).get_target(), _src, &(*i).get_property() );

       }

     };

     template <class V, class E, class Iter, class Dir>

     inline bool operator==(const bidir_incidence_iterator<V,E,Iter,Dir>& x,

                            const bidir_incidence_iterator<V,E,Iter,Dir>& y)

     {

       return x.i == y.i;

     }

     template <class V, class E, class Iter, class Dir>

     inline bool operator!=(const bidir_incidence_iterator<V,E,Iter,Dir>& x,

                            const bidir_incidence_iterator<V,E,Iter,Dir>& y)

     {

       return x.i != y.i;

     }

   }

 } 

 #endif