pull in intersection finder accumulator

include/extractor/guidance/node_based_graph_walker.hpp

@@ -11,6 +11,7 @@
 
 #include <boost/assert.hpp>
 #include <boost/optional.hpp>
+#include <cstdint>
 #include <utility>
 
 namespace osrm
@@ -89,7 +90,7 @@ struct LengthLimitedCoordinateAccumulator
 };
 
 /*
- * The FollowRoadNameSelector tries to follow a given name along a route. We offer methods to skip
+ * The SelectRoadByNameOnlyChoiceAndStraightness tries to follow a given name along a route. We offer methods to skip
  * over bridges/similar situations if desired, following narrow turns
  * This struct offers an example implementation of a possible road selector for traversing the
  * node-based graph using the NodeBasedGraphWalker
@@ -114,6 +115,32 @@ struct SelectRoadByNameOnlyChoiceAndStraightness
     const bool requires_entry;
 };
 
+// find the next intersection given a hop limit
+struct IntersectionFinderAccumulator
+{
+    IntersectionFinderAccumulator(const std::uint8_t hop_limit, const IntersectionGenerator &intersection_generator);
+    // true if the path has traversed enough distance
+    bool terminate();
+
+    // update the accumulator
+    void update(const NodeID from_node,
+                const EdgeID via_edge,
+                const NodeID to_node);
+
+    std::uint8_t hops;
+    const std::uint8_t hop_limit;
+
+    // we need to be able to look-up the intersection
+    const IntersectionGenerator &intersection_generator;
+
+    // the result we are looking for
+    NodeID nid;
+    EdgeID via_edge_id;
+    Intersection intersection;
+};
+
+
+
 template <class accumulator_type, class selector_type>
 boost::optional<std::pair<NodeID, EdgeID>>
 NodeBasedGraphWalker::TraverseRoad(NodeID current_node_id,

src/extractor/guidance/node_based_graph_walker.cpp

@@ -93,6 +93,37 @@ operator()(const NodeID /*nid*/,
         return (*min_element).eid;
 }
 
+// ---------------------------------------------------------------------------------
+IntersectionFinderAccumulator::IntersectionFinderAccumulator(
+    const std::uint8_t hop_limit, const IntersectionGenerator &intersection_generator)
+    : hops(0), hop_limit(hop_limit), intersection_generator(intersection_generator)
+{
+}
+
+bool IntersectionFinderAccumulator::terminate()
+{
+    if (intersection.size() > 2 || hops == hop_limit)
+    {
+        hops = 0;
+        return true;
+    }
+    else
+    {
+        return false;
+    }
+}
+
+void IntersectionFinderAccumulator::update(const NodeID from_node,
+                                           const EdgeID via_edge,
+                                           const NodeID /*to_node*/)
+{
+    ++hops;
+    nid = from_node;
+    via_edge_id = via_edge;
+
+    intersection = intersection_generator.GetConnectedRoads(from_node, via_edge);
+}
+
 } // namespace guidance
 } // namespace extractor
 } // namespace osrm