--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/photosgallery/inc/glxid.h	Thu Dec 17 08:45:44 2009 +0200
@@ -0,0 +1,101 @@
+/*
+* Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies). 
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description:    Type-safe unique id template
+*
+*/
+
+
+
+
+#ifndef T_GLXID_H
+#define T_GLXID_H
+
+#include "e32std.h"
+#include "glxpanic.h"
+
+/** Invalid or undefined id value */
+// Use "id == KGlxIdNone" and "id != KGlxIdNone" to check for
+// id validity.
+class TGlxIdNone {};
+const TGlxIdNone KGlxIdNone = TGlxIdNone();
+
+/**
+ *  TGlxId
+ *
+ *  Type-safe template for ids
+ *  Id value of KMaxTUint is consided to be undefined.
+ *  @usage Define like this:
+ *            class TMyIdBase {}; 
+ *            typedef TGlxId<TMyIdBase> TMyId;
+ *            Now use can use TMyId in other code
+ */
+template <class T> 
+class TGlxId : public T {
+public:
+    inline TGlxId(); 
+    inline TGlxId(const TGlxId<T>& aId);
+    inline TGlxId(TUint aIdValue); 
+    inline TGlxId(const TGlxIdNone&);
+    inline TGlxId<T>& operator=(const TGlxId<T>& aId);
+    inline TGlxId<T>& operator=(TUint aIdValue);
+        
+    inline TGlxId<T>& operator=(const TGlxIdNone&);
+    inline TGlxId<T> operator++(int); // Postfix, keep dummy parameter as int
+    inline TBool operator!=(const TGlxId<T>& aId) const;
+    inline TBool operator==(const TGlxId<T>& aId) const;
+    inline TBool operator!=(const TGlxIdNone&) const;
+    inline TBool operator==(const TGlxIdNone&) const;
+    inline TBool operator>(const TGlxId<T>& aId) const;
+    inline TBool operator<(const TGlxId<T>& aId) const;
+
+    inline TUint Value() const;
+    inline void SetValue(TUint aIdValue); // Allows setting undefined as value (KMaxTUint)
+
+private:
+    TUint iIdValue;
+};
+
+/**
+ * MGlxIdProvider
+ * Abstract interface class to provide ids 
+ * Define as MGlxIdProvider<TMyId>
+ */ 
+template <class T>
+class MGlxIdProvider {
+public:
+    /**
+     * getNextId
+     * Returns the next unique id.
+     * Returns value in the argument, since otherwise cannot have the same
+     * deriving class provide multiple different types of ids
+     */
+    virtual void NextId(T& aId) = 0;
+};
+
+/**
+ * TGlxDefaultIdProvider
+ * Simple implementation of id provider
+ */ 
+template <class T>
+class TGlxDefaultIdProvider : public MGlxIdProvider<T> {
+private:
+    TUint iNextIdValue;
+public:
+    inline TGlxDefaultIdProvider();
+    virtual void NextId(T& aId);
+};
+
+#include "glxid.inl"
+
+#endif // T_GLXID_H