// Copyright (c) 2004-2009 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:

// CHeapWrapper implementation

// 

//

/**

 @file

 @internalTechnology

*/

#include "sbheapwrapper.h"

#include <connect/panic.h>

namespace conn

	{

	CHeapWrapper* CHeapWrapper::NewL()

	/**

	Symbian 1st phase constructor

	@return pointer to a newly created CHeapWrapper object

	*/

		{

		CHeapWrapper* self = new (ELeave) CHeapWrapper();

		return self;

		}

	TPtrC8& CHeapWrapper::ReadBufferL(const RChunk& aChunk)

	/**

	Getter for the GSH descriptor

	@param aChunk The RChunk to interrogate for the heap information

	@return reference to the descriptor stored on the global shared heap

	*/

		{

		if (Header(aChunk).LockedFlag())

			{

			User::Leave(KErrInUse);

			}

		CleanReadBuffer();

		iReadBuf = new (ELeave) TPtrC8(Buffer(aChunk));

		return *iReadBuf;

		}

	TPtr8& CHeapWrapper::WriteBufferL(const RChunk& aChunk)

	/**

	Lock the heap and return a reference to the descriptor on the GSH

	@param aChunk The RChunk to interrogate for the heap information

	@return reference to the descriptor stored on the global shared heap

	*/

		{

		if (Header(aChunk).LockedFlag())

			{

			User::Leave(KErrInUse);

			}

		CleanReadBuffer();

		TPtr8& des = Buffer(aChunk);

		// Blank the descriptor as it's a write buffer

		des.Zero();

		return des;

		}

	THeapWrapperHeader& CHeapWrapper::Header(const RChunk& aChunk) const

	/**

	Getter for the protocol structure

	@param aChunk The RChunk to interrogate for the heap information

	@return Pointer to the header structure containing heap protocol information

	*/

		{

		return *reinterpret_cast<THeapWrapperHeader*>(aChunk.Base() + KHeaderOffset);

		}

	TInt CHeapWrapper::ResetHeap(const RChunk& aChunk)

	/**

	Reset all of the protocol data in the stack if we're the first users

	@param aChunk The RChunk to interrogate for the heap information

	@return KErrNone always.

	*/

		{

		TInt err = KErrNone;

		TUint8* heapPtr = aChunk.Base();

		new (&Header(aChunk)) THeapWrapperHeader;

		THeapWrapperHeader& header = Header(aChunk);

		header.iFinished = ETrue;

		header.SetLockedFlag(EFalse);

		// placement new a new descriptor on the heap to initialise it

		new (heapPtr + KDescriptorOffset) TPtr8(heapPtr + KDataOffset, 0, aChunk.Size() - KDataOffset);

		return err;

		}

	TPtr8& CHeapWrapper::Buffer(const RChunk& aChunk)

 	/**

 	@param aChunk The RChunk to interrogate for the heap information

 	@return reference to the descriptor stored on the global shared heap

 	*/

  		{

  		TUint8* heapPtr = aChunk.Base();

		// Set the descriptor

		TPtr8* descriptor = reinterpret_cast<TPtr8*>(heapPtr + KDescriptorOffset);

		const TInt length = descriptor->Length();

		const TInt maxLength = descriptor->MaxLength();

		descriptor->Set(heapPtr + KDataOffset, length, maxLength);

		return *descriptor;

		}

	void CHeapWrapper::CleanReadBuffer()

	/**

	Delete and NULL the read buffer if necessary

	*/

		{

		delete iReadBuf;

		iReadBuf = NULL;

		}

	CHeapWrapper::~CHeapWrapper()

		{

		CleanReadBuffer();

		}

	}