--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/propagation/model/propagation-cache.h	Mon May 21 19:15:32 2012 +0400
@@ -0,0 +1,86 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2012 Telum (www.telum.ru)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Kirill Andreev <andreev@telum.ru>
+ */
+#ifndef PROPAGATION_CACHE_H_
+#define PROPAGATION_CACHE_H_
+
+#include "ns3/mobility-model.h"
+#include <map>
+
+namespace ns3
+{
+/**
+ * \ingroup propagation
+ * \brief Constructs a cache of objects, where each obect is responsible for a single propagation path loss calculations.
+ * Propagation path a-->b and b-->a is the same thing. Propagation path is identified by
+ * a couple of MobilityModels and a spectrum model UID
+ */
+template<class T>
+class PropagationCache
+{
+public:
+  PropagationCache () {};
+  ~PropagationCache () {};
+  Ptr<T> GetPathData (Ptr<const MobilityModel> a, Ptr<const MobilityModel> b, uint32_t modelUid)
+  {
+    PropagationPathIdentifier key = PropagationPathIdentifier (a, b, modelUid);
+    typename PathCache::iterator it = m_pathCache.find (key);
+    if (it == m_pathCache.end ())
+      {
+        Ptr<T> newPath = CreateObject<T> ();
+        m_pathCache.insert (std::make_pair (key, newPath));
+        return newPath;
+      }
+    return it->second;
+  };
+private:
+  /// Each path is identified by
+  struct PropagationPathIdentifier
+  {
+    PropagationPathIdentifier (Ptr<const MobilityModel> a, Ptr<const MobilityModel> b, uint32_t modelUid) :
+      m_srcMobility (a), m_dstMobility (b), m_spectrumModelUid (modelUid)
+    {};
+    Ptr<const MobilityModel> m_srcMobility;
+    Ptr<const MobilityModel> m_dstMobility;
+    uint32_t m_spectrumModelUid;
+    bool operator < (const PropagationPathIdentifier & other) const
+    {
+      if (m_spectrumModelUid != other.m_spectrumModelUid)
+        {
+          return m_spectrumModelUid < other.m_spectrumModelUid;
+        }
+      /// Links are supposed to be symmetrical!
+      if (std::min (m_dstMobility, m_srcMobility) != std::min (other.m_dstMobility, other.m_srcMobility))
+        {
+          return std::min (m_dstMobility, m_srcMobility) < std::min (other.m_dstMobility, other.m_srcMobility);
+        }
+      if (std::max (m_dstMobility, m_srcMobility) != std::max (other.m_dstMobility, other.m_srcMobility))
+        {
+          return std::max (m_dstMobility, m_srcMobility) < std::max (other.m_dstMobility, other.m_srcMobility);
+        }
+      return false;
+    }
+  };
+  typedef std::map<PropagationPathIdentifier, Ptr<T> > PathCache;
+private:
+  PathCache m_pathCache;
+};
+} // namespace ns3
+
+#endif // PROPAGATION_CACHE_H_