--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libraries/clogger/debugRouter/dobject_compat.h	Wed Jun 23 15:52:26 2010 +0100
@@ -0,0 +1,102 @@
+// dobject_compat.h
+// 
+// Copyright (c) 2007 - 2010 Accenture. All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of the "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:
+// Accenture - Initial contribution
+//
+
+#ifndef DOBJECT_COMPAT_H
+#define DOBJECT_COMPAT_H
+
+#include <kernel.h>
+
+__ASSERT_COMPILE(sizeof(DObject) == 6*4 || sizeof(DObject) == 8*4); // We can't cope if the size changes again!
+#define DOBJECT_PADDING TUint64 _padding
+const TBool KCompiledUsingOldDefinition = sizeof(DObject) == 6*4;
+#define ADD_PADDING(type, variablePtr) (*reinterpret_cast<type*>((TUint8*)variablePtr + sizeof(TUint64)))
+#define SUBTRACT_PADDING(type, variablePtr) (*reinterpret_cast<type*>((TUint8*)variablePtr - sizeof(TUint64)))
+
+
+template <class T>
+class TemplatedPadder
+	{
+public:
+	inline static T& AddPadding(T* aPtr)
+		{
+		return ADD_PADDING(T, aPtr);
+		}
+	inline static T& SubtractPadding(T* aPtr)
+		{
+		return SUBTRACT_PADDING(T, aPtr);
+		}
+	};
+
+template <class T>
+inline T& AddPadding(T* aPtr)
+	{
+	return TemplatedPadder<T>::AddPadding(aPtr);
+	}
+
+template <class T>
+inline T& SubtractPadding(T* aPtr)
+	{
+	return TemplatedPadder<T>::SubtractPadding(aPtr);
+	}
+
+TBool CalculateDObjectSize(); // returns false if unable to determine 
+extern TBool gRunningWithOldDefinition;
+
+/* The SAFE_MEMBER macro exists because DObject grew by 64 bits between 9.1 and 9.2, therefore to write a 
+ * DObject-derived class (such as a DLogicalChannel in an LDD) that can be compiled on one but also works on the
+ * other requires that you be very careful accessing member data of your DObject-derived objects, because the 
+ * offsets are different on the two OS releases. This macro abstracts the differences away by calculating when
+ * an 8 byte correction needs to be applied to where the compiler thinks the variable is versus where the runtime
+ * knows it is. By necessity, it has a weird definition, that relies on the above helper macros and also on
+ * CalculateDObjectSize being called at some point before the first time any code using SAFE_MACRO is run.
+ * It is recommended that for an LDD, you call it from within your DECLARE_EXTENSION_LDD before doing anything
+ * else.
+ * 
+ * SAFE_MEMBER can only be used to access member data of DObject-derived classes, and should be used in ALL 
+ * places where the instance variables are used or set, this includes instance variables of the superclass and
+ * instance variables in DObject-derived objects you define yourself. Accesses to instance variables of DObject
+ * itself must NOT use this macro, since the DObject variable offsets do not change. In order to make sure your
+ * class is large enough and that the macro can be used consistantly, you must include a DOBJECT_PADDING at 
+ * the *end* of all of your DObject subclass definition. You won't get any warning if you forget to do this,
+ * It will just crash. Likewise if you use SAFE_MEMBER to access the member data of the DObject itself.
+ * 
+ * In other words:
+ * DO use SAFE_MEMBER to access the member data of DMyClassThatIsDerivedFromDObject
+ * DO use SAFE_MEMBER to access the member data of DLogicalChannel/DLogicalDevice/DThread etc
+ * DON'T use it to access the member data of DObject itself
+ * ALWAYS include a DOBJECT_PADDING at the end of your DMyDObjectDerivedClass - ie after any other member data
+ * 
+ */
+
+#define SAFE_MEMBER(variable) ( \
+	(KCompiledUsingOldDefinition && gRunningWithOldDefinition) ? variable : ( \
+	(KCompiledUsingOldDefinition && !gRunningWithOldDefinition) ? AddPadding(&variable) : ( \
+	(!KCompiledUsingOldDefinition && gRunningWithOldDefinition) ? SubtractPadding(&variable) : ( \
+	/* running and compiling with new-definition DObject */ variable ))))
+
+/* Old definition that doesn't require templating to work, (so is callable from non-C++). A consequence is you
+ * have to explicitly give the type of the variable.
+ */
+//#define SAFE_MEMBER(type, variable) ( \
+//	(KCompiledUsingOldDefinition && gRunningWithOldDefinition) ? variable : ( \
+//	(KCompiledUsingOldDefinition && !gRunningWithOldDefinition) ? ADD_PADDING(type, &variable) : ( \
+//	(!KCompiledUsingOldDefinition && gRunningWithOldDefinition) ? SUBTRACT_PADDING(type, &variable) : ( \
+//	/* running and compiling with new-definition DObject */ variable ))))
+
+
+/* These macros are equivalent to _FOFF and _LOFF and should be used whenever
+ * f refers to a member variable that you would need to use SAFE_MEMBER on
+ */
+#define _SAFE_FOFF(c,f)			(((TInt)&  SAFE_MEMBER((((c *)0x1000)->f) )  )-0x1000)
+#define _SAFE_LSOFF(p,T,f) ((T*)(((TUint8*)(p))-_SAFE_FOFF(T,f)))
+
+#endif