--- a/src/topology-read/model/topology-reader.cc	Mon Dec 12 19:00:45 2011 +0300
+++ b/src/topology-read/model/topology-reader.cc	Tue Dec 13 00:14:44 2011 +0100
@@ -49,7 +49,7 @@
 }
 
 void
-TopologyReader::SetFileName (const std::string fileName)
+TopologyReader::SetFileName (const std::string &fileName)
 {
   m_fileName = fileName;
 }
@@ -94,7 +94,7 @@
 }
 
 
-TopologyReader::Link::Link ( Ptr<Node> fromPtr, std::string fromName, Ptr<Node> toPtr, std::string toName )
+TopologyReader::Link::Link ( Ptr<Node> fromPtr, const std::string &fromName, Ptr<Node> toPtr, const std::string &toName )
 {
   m_fromPtr = fromPtr;
   m_fromName = fromName;
@@ -131,14 +131,14 @@
 }
 
 std::string
-TopologyReader::Link::GetAttribute (std::string name) const
+TopologyReader::Link::GetAttribute (const std::string &name) const
 {
   NS_ASSERT_MSG (m_linkAttr.find (name) == m_linkAttr.end (), "Requested topology link attribute not found");
   return m_linkAttr.find (name)->second;
 }
 
 bool
-TopologyReader::Link::GetAttributeFailSafe (std::string name, std::string &value) const
+TopologyReader::Link::GetAttributeFailSafe (const std::string &name, std::string &value) const
 {
   if ( m_linkAttr.find (name) == m_linkAttr.end () )
     {
@@ -149,7 +149,7 @@
 }
 
 void
-TopologyReader::Link::SetAttribute (std::string name, std::string &value)
+TopologyReader::Link::SetAttribute (const std::string &name, const std::string &value)
 {
   m_linkAttr[name] = value;
 }

--- a/src/topology-read/model/topology-reader.h	Mon Dec 12 19:00:45 2011 +0300
+++ b/src/topology-read/model/topology-reader.h	Tue Dec 13 00:14:44 2011 +0100
@@ -57,7 +57,7 @@
   /**
    * \brief Constant iterator to scan the map of link attributes.
    */
-    typedef std::map<std::string, std::string >::const_iterator ConstAttributesIterator;
+    typedef std::map<std::string, std::string>::const_iterator ConstAttributesIterator;
 
     /**
      * \brief Constructor
@@ -66,7 +66,7 @@
      * \param toPtr Ptr to the node the link is directed to
      * \param toName name of the node the link is directed to
      */
-    Link ( Ptr<Node> fromPtr, std::string fromName, Ptr<Node> toPtr, std::string toName );
+    Link ( Ptr<Node> fromPtr, const std::string &fromName, Ptr<Node> toPtr, const std::string &toName );
 
     /**
      * \brief Returns a Ptr<Node> to the "from" node of the link
@@ -95,7 +95,7 @@
      *
      * \return the value of the attribute
      */
-    std::string GetAttribute (std::string name) const;
+    std::string GetAttribute (const std::string &name) const;
     /**
      * \brief Returns the value of a link attribute.
      * \param name the name of the attribute
@@ -103,13 +103,13 @@
      *
      * \return true if the attribute was defined, false otherwise.
      */
-    bool GetAttributeFailSafe (std::string name, std::string &value) const;
+    bool GetAttributeFailSafe (const std::string &name, std::string &value) const;
     /**
      * \brief Sets an arbitrary link attribute.
      * \param name the name of the attribute
      * \param value the value of the attribute
      */
-    void SetAttribute (std::string name, std::string &value);
+    void SetAttribute (const std::string &name, const std::string &value);
     /**
      * \brief Returns an iterator to the begin of the attributes.
      * \return a const iterator to the first attribute of a link.
@@ -127,7 +127,7 @@
     Ptr< Node > m_fromPtr;
     std::string m_toName;
     Ptr< Node > m_toPtr;
-    std::map<std::string, std::string > m_linkAttr;
+    std::map<std::string, std::string> m_linkAttr;
   };
 
   /**
@@ -157,7 +157,7 @@
    * \brief Sets the input file name.
    * \param fileName the input file name.
    */
-  void SetFileName (const std::string fileName);
+  void SetFileName (const std::string &fileName);
 
   /**
    * \brief Returns the input file name.