--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/textrendering/textformatting/undo/UniqueInstanceImpl.h	Tue Feb 02 02:02:46 2010 +0200
@@ -0,0 +1,156 @@
+/*
+* Copyright (c) 2000-2009 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: 
+*
+*/
+
+
+#ifndef UNIQUEINSTANCEIMPL_H_
+#define UNIQUEINSTANCEIMPL_H_
+
+#include "UniqueInstance.h"
+
+namespace UniqueInstance
+{
+
+/**
+@internalComponent
+*/
+void DestroyRUniqueInstance(void* runique);
+/**
+ * Reference-counted object.
+ *
+ * @internalComponent
+ * @since App-frameworks6.1
+ */
+struct SElement
+	{
+	TInt iRefCount;
+	void* iObject;
+	};
+
+/**
+ * Skip list holding sorted, reference counted objects
+ *
+ * @internalComponent
+ * @since App-frameworks6.1
+ */
+class RSkipList
+	{
+public:
+	struct TSection
+		{
+		TSection* iLinks[1];
+		SElement iElement;
+		};
+
+	RSkipList& operator=(const RSkipList&);
+	RSkipList(const RSkipList&);
+
+	void TestLinks(TSection* aStart, TSection* aEnd, TInt aLink) const;
+
+	RSkipList() : iSentinel(0), iCompare(0) {}
+	~RSkipList();
+	void Open(TCompareFn* aCompare, TInt aMaxLinks);
+	void Close();
+
+	/**
+	 * Adds an element only if it already exists, otherwise returns 0
+	 */
+	SElement* AddExisting(void* aElt);
+	/**
+	 * Adds a new element. aNewElt must not already have an equivalent in this
+	 * skip list.
+	 */
+	SElement* AddNewL(void* aNewElt);
+	/**
+	 * Removes the element, no matter what its reference count is. Return a pointer
+	 * to the object, which is now no longer owned.
+	 */
+	void* Remove(void* aNoLongerNeeded);
+	/**
+	 * Returns true iff skip list has no elements.
+	 */
+	TBool IsEmpty() const;
+	/**
+	 * Runs tests on the integrity of the skip list.
+	 * Returns the number of elements in the list.
+	 */
+	TInt Test() const;
+
+private:
+	TSection*	iSentinel;
+	TInt		iLinkCount;
+	TCompareFn*	iCompare;
+
+	TSection** FirstLink() const;
+
+	TInt GenerateNumLinks() const;
+	};
+}
+
+/**
+ * Implements the unique instance repository behaviour
+ *
+ * @internalComponent
+ * @since App-frameworks6.1
+ */
+NONSHARABLE_CLASS(UniqueInstance::CRepositoryImpl) : public CBase
+	{
+public:
+	CRepositoryImpl(TCompareFn* aCompare, TDeleteFn* aDelete, TCopyFnL* aCopyL,
+		TInt aObjectSize);
+	~CRepositoryImpl();
+	void ConstructL(TInt aMaxLinks);
+
+	/**
+	 * Adds aElt to the list, passing ownership.
+	 */
+	SElement*	InsertOrIncL(void* aElt);
+	/**
+	 * Adds aElt to the list with the caller retaining ownership.
+	 */
+	SElement*	IncOrCopyL(void* aElt);
+	/**
+	 * Deletes from the list. aNoLongerNeeded points to an element of the list.
+	 */
+	void		DeleteOrDec(UniqueInstance::SElement* aNoLongerNeeded);
+	/**
+	 * Removes from the list, passing ownership back to the caller.
+	 */
+	void*		DetatchOrCopyL(UniqueInstance::SElement* aWritableCopyNeeded);
+	/**
+	 * Returns a prototype null element. Ownership is retained.
+	 */
+	SElement*	NullElement();
+	/**
+	 * Compares the element pointer passed against the prototype null element.
+	 */
+	TBool		IsNull(SElement* a) const;
+	/**
+	 * Runs an integrity check. Panics on failure.
+	 */
+	void		Test() const;
+
+private:
+	TCompareFn*	iCompare;
+	TDeleteFn*	iDelete;
+	TCopyFnL*	iCopyL;
+	TInt		iObjectSize;
+
+	SElement	iNullElement;
+	RSkipList	iSkipList;
+	};
+
+#endif	// UNIQUEINSTANCEIMPL_H_