Parallelize generation of the edge-expanded-edges.

include/util/concurrent_id_map.hpp

@@ -0,0 +1,57 @@
+#ifndef CONCURRENT_ID_MAP_HPP
+#define CONCURRENT_ID_MAP_HPP
+
+#include <boost/interprocess/sync/interprocess_upgradable_mutex.hpp>
+#include <boost/interprocess/sync/scoped_lock.hpp>
+#include <boost/interprocess/sync/sharable_lock.hpp>
+
+#include <unordered_map>
+
+namespace osrm
+{
+namespace util
+{
+
+/**
+ * This is a special purpose map for caching incrementing IDs
+ */
+template <typename KeyType, typename ValueType, typename HashType = std::hash<KeyType>>
+struct ConcurrentIDMap
+{
+    static_assert(std::is_unsigned<ValueType>::value, "Only unsigned integer types are supported.");
+
+    using UpgradableMutex = boost::interprocess::interprocess_upgradable_mutex;
+    using ScopedReaderLock = boost::interprocess::sharable_lock<UpgradableMutex>;
+    using ScopedWriterLock = boost::interprocess::scoped_lock<UpgradableMutex>;
+
+    std::unordered_map<KeyType, ValueType, HashType> data;
+    mutable UpgradableMutex mutex;
+
+    const ValueType ConcurrentFindOrAdd(const KeyType &key)
+    {
+        {
+            ScopedReaderLock sentry{mutex};
+            const auto result = data.find(key);
+            if (result != data.end())
+            {
+                return result->second;
+            }
+        }
+        {
+            ScopedWriterLock sentry{mutex};
+            const auto result = data.find(key);
+            if (result != data.end())
+            {
+                return result->second;
+            }
+            const auto id = static_cast<ValueType>(data.size());
+            data[key] = id;
+            return id;
+        }
+    }
+};
+
+} // util
+} // osrm
+
+#endif // CONCURRENT_ID_MAP_HPP

include/util/guidance/turn_lanes.hpp

@@ -7,6 +7,7 @@
 #include <unordered_map>
 #include <vector>
 
+#include "util/concurrent_id_map.hpp"
 #include "util/typedefs.hpp"
 
 #include <boost/functional/hash.hpp>
@@ -97,7 +98,7 @@ class LaneTupleIdPair
     }
 };
 
-using LaneDataIdMap = std::unordered_map<LaneTupleIdPair, LaneDataID, boost::hash<LaneTupleIdPair>>;
+using LaneDataIdMap = ConcurrentIDMap<LaneTupleIdPair, LaneDataID, boost::hash<LaneTupleIdPair>>;
 
 } // namespace guidance
 } // namespace util