1.1 --- a/src/lemon/graph_utils.h	Mon Nov 08 08:40:37 2004 +0000
     1.2 +++ b/src/lemon/graph_utils.h	Mon Nov 08 15:22:39 2004 +0000
     1.3 @@ -90,6 +90,36 @@
     1.4      }
     1.5      return num;
     1.6    }
     1.7 +
     1.8 +  /// Finds an edge between two nodes of a graph.
     1.9 +
    1.10 +  /// Finds an edge from node \c u to node \c v in graph \c g.
    1.11 +  ///
    1.12 +  /// If \c prev is \ref INVALID (this is the default value), then
    1.13 +  /// it finds the first edge from \c u to \c v. Otherwise it looks for
    1.14 +  /// the next edge from \c u to \c v after \c prev.
    1.15 +  /// \return The found edge or \ref INVALID if there is no such an edge.
    1.16 +  ///
    1.17 +  /// Thus you can iterate through each edge from \c u to \c v as it follows.
    1.18 +  /// \code
    1.19 +  /// for(Edge e=findEdge(g,u,v);e!=INVALID;e=findEdge(g,u,v,e)) {
    1.20 +  ///   ...
    1.21 +  /// }
    1.22 +  /// \endcode
    1.23 +  /// \todo We may want to use the \ref concept::GraphBase "GraphBase"
    1.24 +  /// interface here...
    1.25 +  /// \bug Untested ...
    1.26 +  template <typename Graph>
    1.27 +  typename Graph::Edge findEdge(const Graph &g,
    1.28 +		typename Graph::Node u, typename Graph::Node v,
    1.29 +		typename Graph::Edge prev = INVALID) 
    1.30 +  {
    1.31 +    typename Graph::OutEdgeIt e(g,prev);
    1.32 +    if(prev==INVALID) g.first(e,u);
    1.33 +    else ++e;
    1.34 +    while(e!=INVALID && g.tail(e)!=v) ++e;
    1.35 +    return e;
    1.36 +  }
    1.37    
    1.38    ///\e
    1.39