reduce size of InternalExtractorEdge by using single-precision values

include/extractor/internal_extractor_edge.hpp

@@ -20,23 +20,37 @@ namespace extractor
 
 namespace detail
 {
-// these are used for duration based mode of transportations like ferries
-OSRM_STRONG_TYPEDEF(double, ValueByEdge)
-OSRM_STRONG_TYPEDEF(double, ValueByMeter)
-using ByEdgeOrByMeterValue = mapbox::util::variant<detail::ValueByEdge, detail::ValueByMeter>;
-
-struct ToValueByEdge
+// Use a single float to pack two positive values:
+//  * by_edge: + sign, value >= 0, value used as the edge weight
+//  * by_meter: - sign, value > 0, value used as a denominator in distance / value
+struct ByEdgeOrByMeterValue
 {
-    ToValueByEdge(double distance_) : distance(distance_) {}
-
-    ValueByEdge operator()(const ValueByMeter by_meter) const
+    struct ValueByEdge
     {
-        return ValueByEdge{distance / static_cast<double>(by_meter)};
+    } static const by_edge;
+    struct ValueByMeter
+    {
+    } static const by_meter;
+
+    ByEdgeOrByMeterValue() : value(0.f) {}
+
+    ByEdgeOrByMeterValue(ValueByEdge, double input)
+    {
+        BOOST_ASSERT(input >= 0.f);
+        value = static_cast<value_type>(input);
     }
 
-    ValueByEdge operator()(const ValueByEdge by_edge) const { return by_edge; }
+    ByEdgeOrByMeterValue(ValueByMeter, double input)
+    {
+        BOOST_ASSERT(input > 0.f);
+        value = -static_cast<value_type>(input);
+    }
 
-    double distance;
+    double operator()(double distance) { return value >= 0 ? value : -distance / value; }
+
+  private:
+    using value_type = float;
+    value_type value;
 };
 }
 
@@ -60,7 +74,7 @@ struct InternalExtractorEdge
                  false,
                  guidance::TurnLaneType::empty,
                  guidance::RoadClassification()),
-          weight_data(detail::ValueByMeter{0.0}), duration_data(detail::ValueByMeter{0.0})
+          weight_data(), duration_data()
     {
     }
 
@@ -113,8 +127,8 @@ struct InternalExtractorEdge
         return InternalExtractorEdge(MIN_OSM_NODEID,
                                      MIN_OSM_NODEID,
                                      SPECIAL_NODEID,
-                                     detail::ValueByMeter{0.0},
-                                     detail::ValueByMeter{0.0},
+                                     WeightData(),
+                                     DurationData(),
                                      false, // forward
                                      false, // backward
                                      false, // roundabout
@@ -131,8 +145,8 @@ struct InternalExtractorEdge
         return InternalExtractorEdge(MAX_OSM_NODEID,
                                      MAX_OSM_NODEID,
                                      SPECIAL_NODEID,
-                                     detail::ValueByMeter{0.0},
-                                     detail::ValueByMeter{0.0},
+                                     WeightData(),
+                                     DurationData(),
                                      false, // forward
                                      false, // backward
                                      false, // roundabout

include/extractor/node_based_edge.hpp

@@ -48,6 +48,7 @@ struct NodeBasedEdge
     guidance::RoadClassification road_classification;
 };
 
+#pragma pack(push, 4)
 struct NodeBasedEdgeWithOSM : NodeBasedEdge
 {
     NodeBasedEdgeWithOSM(OSMNodeID source,
@@ -68,6 +69,7 @@ struct NodeBasedEdgeWithOSM : NodeBasedEdge
     OSMNodeID osm_source_id;
     OSMNodeID osm_target_id;
 };
+#pragma pack(pop)
 
 // Impl.
 

src/extractor/extraction_containers.cpp

@@ -427,10 +427,8 @@ void ExtractionContainers::PrepareEdges(ScriptingEnvironment &scripting_environm
             const double distance = util::coordinate_calculation::greatCircleDistance(
                 edge_iterator->source_coordinate, target_coord);
 
-            double weight = static_cast<double>(mapbox::util::apply_visitor(
-                detail::ToValueByEdge(distance), edge_iterator->weight_data));
-            double duration = static_cast<double>(mapbox::util::apply_visitor(
-                detail::ToValueByEdge(distance), edge_iterator->duration_data));
+            auto weight = edge_iterator->weight_data(distance);
+            auto duration = edge_iterator->duration_data(distance);
 
             ExtractionSegment extracted_segment(
                 edge_iterator->source_coordinate, target_coord, distance, weight, duration);

src/extractor/extractor_callbacks.cpp

@@ -119,20 +119,20 @@ void ExtractorCallbacks::ProcessWay(const osmium::Way &input_way, const Extracti
     InternalExtractorEdge::WeightData forward_weight_data;
     InternalExtractorEdge::WeightData backward_weight_data;
 
-    const auto toValueByEdgeOrByMeter =
-        [&nodes](const double by_way, const double by_meter) -> detail::ByEdgeOrByMeterValue {
-        if (by_way > 0)
+    const auto toValueByEdgeOrByMeter = [&nodes](const double by_way, const double by_meter) {
+        using Value = detail::ByEdgeOrByMeterValue;
+        if (by_way >= 0)
         {
             // FIXME We divide by the number of edges here, but should rather consider
             // the length of each segment. We would either have to compute the length
             // of the whole way here (we can't: no node coordinates) or push that back
             // to the container and keep a reference to the way.
-            const unsigned num_edges = (nodes.size() - 1);
-            return detail::ValueByEdge{by_way / num_edges};
+            const std::size_t num_edges = (nodes.size() - 1);
+            return Value(Value::by_edge, by_way / num_edges);
         }
         else
         {
-            return detail::ValueByMeter{by_meter};
+            return Value(Value::by_meter, by_meter);
         }
     };