/*
* Copyright (c) 2006 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:   The header file of DevTokenNullStream
*
*/



#ifndef __DEVTOKENNULLSTREAM_H__
#define __DEVTOKENNULLSTREAM_H__

#include <s32strm.h>
#include <s32buf.h>

/**
 * Implementation of the MStreamBuf interface that throws away all data written
 * to it.  It does not support reading
 *
 *  @lib DevTokenShared.dll
 *  @since S60 v3.2.
 */
class TNullBuf : public MStreamBuf
    {
    public:
    
        TNullBuf();
    
        TUint BytesWritten();
        
    private:
    
        virtual void DoWriteL(const TAny* aPtr,TInt aLength);
        
    private:
    
        TUint iBytesWritten;
    }; 


/**
 * A write stream that throws away all its input, but keeps track of how many
 * bytes have been written to it.  It is used for determining the amount of
 * memory needed to store externalised objects.
 * 
 *  @lib DevTokenShared.dll
 *  @since S60 v3.2.
 */
class RNullWriteStream : public RWriteStream
    {
    public:
        RNullWriteStream();
        TUint BytesWritten();
    
    private:
        TNullBuf iSink;
    };

#endif //__DEVTOKENNULLSTREAM_H__

//EOF