add andrei alexandrescu's scope guard implementation

src/loki/RefToValue.h

@@ -0,0 +1,70 @@
+////////////////////////////////////////////////////////////////////////////////
+// The Loki Library
+// Copyright (c) 2006 Richard Sposato
+// Copyright (c) 2006 Peter Kümmel
+// Permission to use, copy, modify, distribute and sell this software for any 
+//     purpose is hereby granted without fee, provided that the above copyright 
+//     notice appear in all copies and that both that copyright notice and this 
+//     permission notice appear in supporting documentation.
+// The authors make no representations about the 
+//     suitability of this software for any purpose. It is provided "as is" 
+//     without express or implied warranty.
+////////////////////////////////////////////////////////////////////////////////
+#ifndef LOKI_REFTOVALUE_INC_
+#define LOKI_REFTOVALUE_INC_
+
+// $Id: RefToValue.h 751 2006-10-17 19:50:37Z syntheticpp $
+
+
+namespace Loki
+{
+
+    ////////////////////////////////////////////////////////////////////////////////
+    ///  \class RefToValue
+    ///
+    ///  \ingroup SmartPointerGroup 
+    ///  Transports a reference as a value
+    ///  Serves to implement the Colvin/Gibbons trick for SmartPtr/ScopeGuard
+    ////////////////////////////////////////////////////////////////////////////////
+
+    template <class T>
+    class RefToValue
+    {   
+    public:
+
+        RefToValue(T& ref) : ref_(ref) 
+        {}
+
+        RefToValue(const RefToValue& rhs) : ref_(rhs.ref_)
+        {}
+
+        operator T& () const 
+        {
+            return ref_;
+        }
+
+    private:
+        // Disable - not implemented
+        RefToValue();
+        RefToValue& operator=(const RefToValue&);
+
+        T& ref_;
+    };
+
+
+    ////////////////////////////////////////////////////////////////////////////////
+    ///  \ingroup ExceptionGroup 
+    ///  RefToValue creator.
+    ////////////////////////////////////////////////////////////////////////////////
+
+    template <class T>
+    inline RefToValue<T> ByRef(T& t)
+    {
+        return RefToValue<T>(t);
+    }    
+
+}
+
+
+#endif // end file guardian
+