// Copyright (c) 1998-2009 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:

 //

 #include "US_STD.H"

 EXPORT_C RShareBuf::RShareBuf()

 	: iHost(NULL)

 /** Constructs an empty shared stream buffer object.

 Call one of the Open() functions to prepare the stream. */

 	{}

 EXPORT_C void RShareBuf::Open(TStreamExchange& aHost,TStreamPos aPos,TInt aMode)

 /** Prepares the shared stream buffer for streaming.

 The function sets the read mark and/or the write mark to the specified position 

 within the host stream.

 @param aHost The object that manages shared streaming.

 @param aPos The position within the host stream.

 @param aMode The streaming mode. This can be read and/or write, as indicated 

 by the ERead and EWrite bits.

 @see MStreamBuf::TRead

 @see MStreamBuf::TWrite */

 	{

 	iHost=&aHost;

 	if (aMode&ERead)

 		iRMark=aPos;

 	else

 		iRMark.Clear();

 	if (aMode&EWrite)

 		iWMark=aPos;

 	else

 		iWMark.Clear();

 	}

 EXPORT_C void RShareBuf::DoRelease()

 //

 // Withdraw this stream buffer's marks.

 //

 	{

 	if (iHost!=NULL)

 		{

 		TStreamExchange& host=*iHost;

 		iRMark.Withdraw(host);

 		iWMark.Withdraw(host);

 		iHost=NULL;

 		}

 	}

 EXPORT_C TInt RShareBuf::DoReadL(TAny* aPtr,TInt aMaxLength)

 //

 // Read up to aMaxLength bytes.

 //

 	{

 	return iRMark.ReadL(Host(),aPtr,aMaxLength);

 	}

 EXPORT_C TInt RShareBuf::DoReadL(TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus)

 //

 // Read up to aMaxLength bytes asynchronously.

 //

 	{

 	return iRMark.ReadL(Host(),aDes,aMaxLength,aStatus);

 	}

 EXPORT_C TStreamTransfer RShareBuf::DoReadL(MStreamInput& anInput,TStreamTransfer aTransfer)

 //

 // Push up to aTransfer bytes into anInput.

 //

 	{

 	return iRMark.ReadL(Host(),anInput,aTransfer);

 	}

 EXPORT_C void RShareBuf::DoWriteL(const TAny* aPtr,TInt aLength)

 //

 // Write aLength bytes.

 //

 	{

 	iWMark.WriteL(Host(),aPtr,aLength);

 	}

 EXPORT_C TInt RShareBuf::DoWriteL(const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus)

 //

 // Write up to aMaxLength bytes asynchronously.

 //

 	{

 	return iWMark.WriteL(Host(),aDes,aMaxLength,aStatus);

 	}

 EXPORT_C TStreamTransfer RShareBuf::DoWriteL(MStreamOutput& anOutput,TStreamTransfer aTransfer)

 //

 // Pull up to aTransfer bytes from anOutput.

 //

 	{

 	return iWMark.WriteL(Host(),anOutput,aTransfer);

 	}

 EXPORT_C TStreamPos RShareBuf::DoSeekL(TMark aMark,TStreamLocation aLocation,TInt anOffset)

 //

 // Position the mark(s) indicated by aMark at anOffset from aLocation.

 //

 	{

 	TStreamExchange& host=Host();

 	if (!aMark)

 		{

 		TStreamMark mark;

 		return mark.SeekL(host,aLocation,anOffset);

 		}

 //

 	__ASSERT_ALWAYS(!(aMark&~(ERead|EWrite)),Panic(EStreamMarkInvalid));

 	TStreamPos pos(0);

 	if (aMark&ERead)

 		{

 		__ASSERT_ALWAYS(aLocation!=EStreamMark||aMark==ERead,Panic(EStreamMarkInvalid));

 		if (!iRMark.RelatesTo(host))

 			__LEAVE(KErrNotReady);

 //

 		pos=iRMark.SeekL(host,aLocation,anOffset);

 		}

 	if (aMark&EWrite)

 		{

 		if (!iWMark.RelatesTo(host))

 			__LEAVE(KErrNotReady);

 //

 		TStreamPos p=iWMark.SeekL(host,aLocation,anOffset);

 		__ASSERT_DEBUG(aMark==EWrite||p==pos,User::Invariant());

 		return p;

 		}

 //

 	return pos;

 	}

 EXPORT_C RShareReadStream::RShareReadStream(TStreamExchange& aHost,TStreamPos aPos)

 /** Constructs the shared read stream object and prepares the shared stream for 

 reading.

 @param aHost The object that manages shared streaming.

 @param aPos The position of the stream within the host stream. Defaults to 

 the beginning of the host stream, if not explicitly specified.

 @see KStreamBeginning */

 	{

 	Open(aHost,aPos);

 	}

 EXPORT_C void RShareReadStream::Open(TStreamExchange& aHost,TStreamPos aPos)

 /** Prepares the shared stream for reading.

 @param aHost The object that manages shared streaming.

 @param aPos The position of the stream within the host stream. Defaults to 

 the beginning of the host stream, if not explicitly specified. */

 	{

 	iSource.Open(aHost,aPos,iSource.ERead);

 	RReadStream::Attach(&iSource);

 	}

 EXPORT_C RShareWriteStream::RShareWriteStream(TStreamExchange& aHost,TStreamPos aPos)

 /** Constructs the shared write stream object and prepares the shared stream for 

 writing.

 @param aHost The object that manages shared streaming.

 @param aPos The position of the stream within the host stream. Defaults to 

 the beginning of the host stream, if not explicitly specified.

 @see KStreamBeginning */

 	{

 	Open(aHost,aPos);

 	}

 EXPORT_C void RShareWriteStream::Open(TStreamExchange& aHost,TStreamPos aPos)

 /** Prepares the shared stream for writing.

 @param aHost The object that manages shared streaming.

 @param aPos The position of the stream within the host stream. Defaults to 

 the beginning of the host stream, if not explicitly specified. */

 	{

 	iSink.Open(aHost,aPos,iSink.EWrite);

 	RWriteStream::Attach(&iSink);

 	}