/*+
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* Copyright (c) 2002-2004 Nokia Corporation and/or its subsidiary(-ies).+
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* All rights reserved.+
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* This component and the accompanying materials are made available+
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* under the terms of "Eclipse Public License v1.0"+
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* which accompanies this distribution, and is available+
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* at the URL "http://www.eclipse.org/legal/epl-v10.html".+
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*+
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* Initial Contributors:+
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* Nokia Corporation - initial contribution.+
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*+
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* Contributors:+
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*+
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* Description:  Iterates over a tree, depth first+
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*+
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*/+
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+
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#ifndef XNDEPTHFIRSTTREEITERATOR_H+
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#define XNDEPTHFIRSTTREEITERATOR_H+
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+
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//  INCLUDES+
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#include <e32base.h>+
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#include "xnchilditerator.h"+
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+
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// Constants+
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/** +
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 * Queue granularity value+
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 */+
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const TInt KMemoryAlocS = 64;+
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+
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+
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template < class T >+
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    class CXnDepthFirstTreeIterator: public CBase, public MXnChildIterator+
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    {+
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public:+
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    /**+
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    * Two-phased constructor.+
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    * @param aStartNode Object to iterate over+
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    */+
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    static CXnDepthFirstTreeIterator< T >* NewL( T& aStartNode );+
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+
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    /**+
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    * Destructor.+
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    */+
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    virtual ~CXnDepthFirstTreeIterator();+
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+
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    /**+
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    * Get the next iterator value.+
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    * @return Next object or NULL if no more values. +
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    */+
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    T* NextL();+
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+
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    /**+
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    * Get the current iterator value.+
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    * @return Current object +
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    */  +
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    T* Value();+
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+
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    /**+
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    * Get the previous iterator value. Obsolete!+
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    * @return NULL +
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    */+
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    T* PreviousL();+
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+
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    /**+
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    * Get the current iterator index. Obsolete!+
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    * @return value 0+
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    */+
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    TUint Index() const;+
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+
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    /**+
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    * Get the current iterator level in the tree.+
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    * @return current level+
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    */+
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    TUint Level() const;+
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+
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protected:+
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+
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    CXnDepthFirstTreeIterator( T* aStartNode );+
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+
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    void ConstructL();+
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+
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private:+
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    //Stack+
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    RPointerArray< T > iStack;+
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    //Object to iterate over+
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    T* iStart;+
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    // Current object+
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    T* iCurrent;+
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+
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    };+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::NewL()+
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// -----------------------------------------------------------------------------+
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//+
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template< class T > CXnDepthFirstTreeIterator< T >*+
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    CXnDepthFirstTreeIterator<T>::NewL( T& aStartNode )+
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    {+
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    CXnDepthFirstTreeIterator<T>* self = +
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        new ( ELeave )CXnDepthFirstTreeIterator< T >( &aStartNode );+
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    CleanupStack::PushL( self );+
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    self->ConstructL();+
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    CleanupStack::Pop();+
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    return self;+
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    }+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::CXnDepthFirstTreeIterator()+
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// C++ default constructor+
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// -----------------------------------------------------------------------------+
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//+
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template< class T > CXnDepthFirstTreeIterator< T >::CXnDepthFirstTreeIterator(+
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    T* aStartNode ):+
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    iStart( aStartNode ),+
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    iCurrent( aStartNode ),+
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    iStack( KMemoryAlocS )+
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    {+
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    }+
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+
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// -----------------------------------------------------------------------------+
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//  CXnDepthFirstTreeIterator< T >::~CXnDepthFirstTreeIterator()+
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//  C++ default destructor.  +
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// -----------------------------------------------------------------------------+
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//  +
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template< class T >+
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    CXnDepthFirstTreeIterator< T >::~CXnDepthFirstTreeIterator()+
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    {+
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    iStack.Close();+
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    }+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::ConstructL()+
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// Symbian 2nd phase constructor can leave.+
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// -----------------------------------------------------------------------------+
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//+
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template< class T > void CXnDepthFirstTreeIterator< T >::ConstructL()+
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    {+
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    iStack.AppendL( iStart );+
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    }+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::NextL()+
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// -----------------------------------------------------------------------------+
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//+
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template< class T > T* CXnDepthFirstTreeIterator< T >::NextL()+
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    {+
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    if( iStack.Count() )+
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        {+
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        // Pop+
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        TInt topIndex( iStack.Count() - 1 );+
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        iCurrent = iStack[topIndex];+
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        iStack.Remove( topIndex );+
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        +
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        RPointerArray< T >& currentChildNodes( iCurrent->Children() );+
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        TInt currentChildCount( currentChildNodes.Count() );+
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       +
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        // Push left most child to top+
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        for( TInt i = currentChildCount - 1; i >= 0; --i )+
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            {+
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            iStack.AppendL( currentChildNodes[i] );+
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            }+
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        }+
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    else+
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        {+
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        iCurrent = NULL;+
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        iStack.Reset();+
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        iStack.AppendL( iStart );+
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        }+
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    return iCurrent;+
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    }+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::Value()+
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// -----------------------------------------------------------------------------+
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//+
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template< class T > T* CXnDepthFirstTreeIterator< T >::Value()+
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    {+
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    return iCurrent;+
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    }+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::PreviousL()+
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// -----------------------------------------------------------------------------+
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//+
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template< class T > T* CXnDepthFirstTreeIterator< T >::PreviousL()+
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    {+
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    return NULL;+
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    }+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::Index()+
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// -----------------------------------------------------------------------------+
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//+
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template< class T > TUint CXnDepthFirstTreeIterator< T >::Index() const+
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    {+
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    return 0;+
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    }+
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+
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// -----------------------------------------------------------------------------+
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// CXnDepthFirstTreeIterator< T >::Level()+
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// Get the current iterator level in the tree.+
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// -----------------------------------------------------------------------------+
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template< class T > TUint CXnDepthFirstTreeIterator< T >::Level() const+
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    {+
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    return iStack.Count();+
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    }+
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+
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+
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#endif    // CXNDEPTHFIRSTTREEITERATOR_H+
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+
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// End of File+
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