sl@0: // Copyright (c) 1998-2010 Nokia Corporation and/or its subsidiary(-ies).
sl@0: // All rights reserved.
sl@0: // This component and the accompanying materials are made available
sl@0: // under the terms of "Eclipse Public License v1.0"
sl@0: // which accompanies this distribution, and is available
sl@0: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: //
sl@0: // Initial Contributors:
sl@0: // Nokia Corporation - initial contribution.
sl@0: //
sl@0: // Contributors:
sl@0: //
sl@0: // Description:
sl@0: //
sl@0: 
sl@0: #include "US_STD.H"
sl@0: 
sl@0: /** Synchronises the stream buffer with the stream, returning any error.
sl@0: 
sl@0: In effect, this ensures that buffered data is delivered to the stream.
sl@0: 
sl@0: This function calls SynchL() inside a TRAPD harness and returns the leave 
sl@0: code if a leave occurs.
sl@0: 
sl@0: @return KErrNone, if successful; otherwise one of the other system wide error 
sl@0: codes.
sl@0: @see MStreamBuf::SynchL()
sl@0: @see MStreamBuf::DoSynchL() */
sl@0: EXPORT_C TInt MStreamBuf::Synch()
sl@0: 	{
sl@0: 	TRAPD(r,SynchL());
sl@0: 	return r;
sl@0: 	}
sl@0: 
sl@0: /** Closes the stream buffer.
sl@0: 
sl@0: This function attempts to synchronise buffered data with the stream before 
sl@0: freeing any resources. All errors are ignored.
sl@0: 
sl@0: @see MStreamBuf::Synch()
sl@0: @see MStreamBuf::Release() */
sl@0: EXPORT_C void MStreamBuf::Close()
sl@0: 	{
sl@0: 	Synch();
sl@0: 	Release();
sl@0: 	}
sl@0: 
sl@0: /** Puts a cleanup item for this object onto the cleanup stack.
sl@0: 
sl@0: This allows allocated resources to be cleaned up if a subsequent leave occurs. */
sl@0: EXPORT_C void MStreamBuf::PushL()
sl@0: 	{
sl@0: 	CleanupReleasePushL(*this);
sl@0: 	}
sl@0: 
sl@0: /** Reads data, asynchronously, from the stream buffer into the specified descriptor; 
sl@0: request completion is guaranteed, even if request initiation fails.
sl@0: 
sl@0: The function calls the virtual function DoReadL(TDes8&,TInt,TRequestStatus&) 
sl@0: to implement this behaviour. The maximum number of bytes to be read is the 
sl@0: value of the maximum length of the descriptor.
sl@0: 
sl@0: @param aDes The target descriptor for the data read from the stream buffer.
sl@0: @param aStatus The request status that indicates the completion status of this 
sl@0: asynchronous request.
sl@0: @return The maximum number of bytes to be read, as used in this request. This 
sl@0: value can be different to the maximum length of the descriptor; this is dependent 
sl@0: on the implementation.
sl@0: @see MStreamBuf::DoReadL() */
sl@0: EXPORT_C TInt MStreamBuf::Read(TDes8& aDes,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	return Read(aDes,aDes.MaxLength(),aStatus);
sl@0: 	}
sl@0: 
sl@0: /** Reads data, asynchronously, from the stream buffer into the specified descriptor; 
sl@0: request completion is guaranteed, even if request initiation fails.
sl@0: 
sl@0: The function calls the virtual function DoReadL(TDes8&,TInt,TRequestStatus&) 
sl@0: to implement this behaviour.
sl@0: 
sl@0: @param aDes The target descriptor for the data read from the stream buffer.
sl@0: @param aMaxLength The maximum number of bytes to be read.
sl@0: @param aStatus The request status that indicates the completion status of this 
sl@0: asynchronous request.
sl@0: @return The maximum number of bytes to be read, as used in this request. This 
sl@0: can be different to the value supplied in aMaxLength; this is dependent on 
sl@0: the implementation.
sl@0: @see MStreamBuf::DoReadL() */
sl@0: EXPORT_C TInt MStreamBuf::Read(TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	TInt len=0;
sl@0: 	TRAPD(r,len=DoReadL(aDes,aMaxLength,aStatus));
sl@0: 	if (r!=KErrNone)
sl@0: 		{
sl@0: 		TRequestStatus* stat=&aStatus;
sl@0: 		User::RequestComplete(stat,r);
sl@0: 		}
sl@0: 	return len;
sl@0: 	}
sl@0: 
sl@0: /** Reads data, asynchronously, from the stream buffer into the specified descriptor.
sl@0: 
sl@0: The function calls the virtual function DoReadL(TDes8&,TInt,TRequestStatus&) 
sl@0: to implement this behaviour. The maximum number of bytes to be read is the 
sl@0: maximum length of the descriptor.
sl@0: 
sl@0: If the function leaves, then no read request will have been initiated.
sl@0: 
sl@0: @param aDes The target descriptor for the data read from the stream buffer.
sl@0: @param aStatus The request status that indicates the completion status of this 
sl@0: asynchronous request.
sl@0: @return The maximum number of bytes to be read, as used in this request. This 
sl@0: value can be different to the maximum length of the descriptor; this is dependent 
sl@0: on the implementation.
sl@0: @see MStreamBuf::DoReadL() */
sl@0: EXPORT_C TInt MStreamBuf::ReadL(TDes8& aDes,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	return DoReadL(aDes,aDes.MaxLength(),aStatus);
sl@0: 	}
sl@0: 
sl@0: /** Reads data from the stream buffer into the specified data sink.
sl@0: 
sl@0: The function uses the virtual function DoReadL(MStreamInput&,TStreamTransfer) 
sl@0: to implement this behaviour.
sl@0: 
sl@0: @param anInput The data sink which is the target for the read operation.
sl@0: @param aMaxLength The maximum amount of data available to be read.
sl@0: @return The amount of data that was not consumed. */
sl@0: EXPORT_C TInt MStreamBuf::ReadL(MStreamInput& anInput,TInt aMaxLength)
sl@0: 	{
sl@0: 	return aMaxLength-DoReadL(anInput,TStreamTransfer(aMaxLength)).Left();
sl@0: 	}
sl@0: 
sl@0: /** Writes data, asynchronously, from the specified descriptor into the stream buffer; 
sl@0: request completion is guaranteed, even if request initiation fails.
sl@0: 
sl@0: The function calls the virtual function DoWriteL(const TDesC8&,TInt,TRequestStatus&) 
sl@0: to implement this behaviour. The maximum number of bytes to be written is 
sl@0: the value of the maximum length of the descriptor.
sl@0: 
sl@0: @param aDes The source descriptor for the data to be written into the stream 
sl@0: buffer.
sl@0: @param aStatus The request status that indicates the completion status of this 
sl@0: asynchronous request.
sl@0: @return The maximum number of bytes to be written, as used in this request. 
sl@0: This can be different to the value supplied in aMaxLength; this is dependent 
sl@0: on the implementation.
sl@0: @see MStreamBuf::DoWriteL() */
sl@0: EXPORT_C TInt MStreamBuf::Write(const TDesC8& aDes,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	return Write(aDes,aDes.Length(),aStatus);
sl@0: 	}
sl@0: 
sl@0: //
sl@0: // Write up to aMaxLength bytes with guaranteed completion.
sl@0: //
sl@0: EXPORT_C TInt MStreamBuf::Write(const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	TInt len=0;
sl@0: 	TRAPD(r,len=DoWriteL(aDes,aMaxLength,aStatus));
sl@0: 	if (r!=KErrNone)
sl@0: 		{
sl@0: 		TRequestStatus* stat=&aStatus;
sl@0: 		User::RequestComplete(stat,r);
sl@0: 		}
sl@0: 	return len;
sl@0: 	}
sl@0: 
sl@0: /** Writes data, asynchronously, from the specified descriptor into the stream buffer.
sl@0: 
sl@0: The function calls the virtual function DoWriteL(const TDesC8&,TInt,TRequestStatus&) 
sl@0: to implement this behaviour. The maximum number of bytes to be written is 
sl@0: the value of the maximum length of the descriptor.
sl@0: 
sl@0: If the function leaves, then no write request will have been initiated.
sl@0: 
sl@0: @param aDes The source descriptor for the data to be written into the stream 
sl@0: buffer.
sl@0: @param aStatus The request status that indicates the completion status of this 
sl@0: asynchronous request.
sl@0: @return The maximum number of bytes to be written, as used in this request. 
sl@0: This can be different to the maximum length of the descriptor; this is dependent 
sl@0: on the implementation.
sl@0: @see MStreamBuf::DoWriteL() */
sl@0: EXPORT_C TInt MStreamBuf::WriteL(const TDesC8& aDes,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	return DoWriteL(aDes,aDes.Length(),aStatus);
sl@0: 	}
sl@0: 
sl@0: /** Writes data into the stream buffer from the specified data source.
sl@0: 
sl@0: The function calls the virtual function DoWriteL(MStreamOutput&,TStreamTransfer) 
sl@0: to implement this behaviour.
sl@0: 
sl@0: @param anOutput The data source for the write operation.
sl@0: @param aMaxLength The maximum amount of data available to be written.
sl@0: @return The amount of data that was not consumed. */
sl@0: EXPORT_C TInt MStreamBuf::WriteL(MStreamOutput& anOutput,TInt aMaxLength)
sl@0: 	{
sl@0: 	return aMaxLength-DoWriteL(anOutput,TStreamTransfer(aMaxLength)).Left();
sl@0: 	}
sl@0: 
sl@0: /** Frees resources before abandoning the stream buffer.
sl@0: 
sl@0: It is called by Release().
sl@0: 
sl@0: This implementation is empty, but classes derived from MStreamBuf can provide 
sl@0: their own implementation, if necessary.
sl@0: 
sl@0: @see MStreamBuf::Release() */
sl@0: EXPORT_C void MStreamBuf::DoRelease()
sl@0: 	{	
sl@0: 	}
sl@0: 
sl@0: /** Synchronises the stream buffer with the stream, leaving if any error occurs.
sl@0: 
sl@0: In effect, this ensures that buffered data is delivered to the stream.
sl@0: 
sl@0: It is called by SynchL().
sl@0: 
sl@0: This implementation is empty, but classes derived from MStreamBuf can provide 
sl@0: their own implementation, if necessary.
sl@0: 
sl@0: @see MStreamBuf::SynchL() */
sl@0: EXPORT_C void MStreamBuf::DoSynchL()
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: #pragma BullseyeCoverage off
sl@0: 
sl@0: //
sl@0: // Cannot read from this stream buffer.
sl@0: //
sl@0: EXPORT_C TInt MStreamBuf::DoReadL(TAny*,TInt)
sl@0: 	{
sl@0: 	Panic(EStreamCannotRead);
sl@0: 	return TInt();
sl@0: 	}
sl@0: 
sl@0: //
sl@0: // Cannot write to this stream buffer.
sl@0: //
sl@0: EXPORT_C void MStreamBuf::DoWriteL(const TAny*,TInt)
sl@0: 	{
sl@0: 	Panic(EStreamCannotWrite);
sl@0: 	}
sl@0: 
sl@0: //
sl@0: // This stream buffer does not support seeking.
sl@0: //
sl@0: EXPORT_C TStreamPos MStreamBuf::DoSeekL(TMark,TStreamLocation,TInt)
sl@0: 	{
sl@0: 	Panic(EStreamCannotSeek);
sl@0: 	TStreamPos streamPos(-1);
sl@0: 	return streamPos;
sl@0: 	}
sl@0: 
sl@0: #pragma BullseyeCoverage on
sl@0: 
sl@0: /** Reads data from the stream buffer into the specified descriptor.
sl@0: 
sl@0: This function is called by ReadL(TDes8&,TInt,TRequestStatus&).
sl@0: 
sl@0: This implementation deals with the request synchronously, and completes the 
sl@0: request with KErrNone. Other implementations may choose to deal with this 
sl@0: in a true asynchronous manner.
sl@0: 
sl@0: In addition, the read operation itself uses the DoReadL(TAny*,TInt) variant.
sl@0: 
sl@0: @param aDes The target descriptor for the data read from the stream buffer. 
sl@0: On return, the length of the descriptor is set to the number of bytes read 
sl@0: from the stream buffer.
sl@0: @param aMaxLength The maximum number of bytes to be read. This value must not 
sl@0: be greater than the maximum length of the descriptor, otherwise the function 
sl@0: raises a STORE-Stream 2 panic.
sl@0: @param aStatus The request status that indicates the completion status of this 
sl@0: asynchronous request.
sl@0: @return The maximum number of bytes to be read, as used in this request. This 
sl@0: implementation uses, and returns, the value supplied in aMaxLength. Other 
sl@0: implementations may choose to use a different value.
sl@0: @see MStreamBuf::ReadL() */
sl@0: EXPORT_C TInt MStreamBuf::DoReadL(TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aMaxLength<=aDes.MaxLength(),Panic(EStreamReadBeyondEnd));
sl@0: 	aDes.SetLength(DoReadL((TUint8*)aDes.Ptr(),aMaxLength));
sl@0: 	TRequestStatus* stat=&aStatus;
sl@0: 	User::RequestComplete(stat,KErrNone);
sl@0: 	return aMaxLength;
sl@0: 	}
sl@0: 
sl@0: /** Reads data from the stream into the specified data sink.
sl@0: 
sl@0: It is called by ReadL(MStreamInput&,TStreamTransfer).
sl@0: 
sl@0: This implementation calls the sink's ReadFromL() function, which performs 
sl@0: the read (transfer) operation.
sl@0: 
sl@0: This implementation of DoReadL() is called for streams that do not have buffering 
sl@0: capabilities, and that are derived directly from this class.
sl@0: 
sl@0: @param anInput The target data sink.
sl@0: @param aTransfer A stream transfer object defining the amount of data available 
sl@0: to be read.
sl@0: @return A stream transfer object defining the amount of data that was not consumed.
sl@0: @see MStreamInput::ReadFromL() */
sl@0: EXPORT_C TStreamTransfer MStreamBuf::DoReadL(MStreamInput& anInput,TStreamTransfer aTransfer)
sl@0: 	{
sl@0: 	return anInput.ReadFromL(*this,aTransfer);
sl@0: 	}
sl@0: 
sl@0: /** Writes data from the specified descriptor into this stream buffer.
sl@0: 
sl@0: This function is called by WriteL(const TDesC8&,TInt,TRequestStatus&).
sl@0: 
sl@0: This implementation deals with the request synchronously, and completes the 
sl@0: request with KErrNone. Other implementations may choose to deal with this 
sl@0: in a true asynchronous manner.
sl@0: 
sl@0: In addition, the write operation itself uses the DoWriteL(TAny*,TInt) variant.
sl@0: 
sl@0: @param aDes The source descriptor for the data to be written into the stream 
sl@0: buffer.
sl@0: @param aMaxLength The number of bytes to be written. This value must not be 
sl@0: greater than the maximum length of the descriptor, otherwise the function 
sl@0: raises a STORE-Stream 6 panic.
sl@0: @param aStatus The request status that indicates the completion status of this 
sl@0: asynchronous request.
sl@0: @return The maximum number of bytes to be written, as used in this request. 
sl@0: This implementation uses, and returns, the value supplied in aMaxLength. Other 
sl@0: implementations may choose to use a different value.
sl@0: @see MStreamBuf::WriteL() */
sl@0: EXPORT_C TInt MStreamBuf::DoWriteL(const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aMaxLength<=aDes.Length(),Panic(EStreamWriteBeyondEnd));
sl@0: 	DoWriteL(aDes.Ptr(),aMaxLength);
sl@0: 	TRequestStatus* stat=&aStatus;
sl@0: 	User::RequestComplete(stat,KErrNone);
sl@0: 	return aMaxLength;
sl@0: 	}
sl@0: 
sl@0: //
sl@0: // Default implementation turning around to anOutput.
sl@0: //
sl@0: EXPORT_C TStreamTransfer MStreamBuf::DoWriteL(MStreamOutput& anOutput,TStreamTransfer aTransfer)
sl@0: 	{
sl@0: 	return anOutput.WriteToL(*this,aTransfer);
sl@0: 	}
sl@0: 
sl@0: /** Sets the pointers that mark out the read and write areas within the intermediate 
sl@0: buffer to null. */
sl@0: EXPORT_C TStreamBuf::TStreamBuf()
sl@0: 	: iRPtr(NULL),iREnd(NULL),iWPtr(NULL),iWEnd(NULL)
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: /** Sets the start and end points of the read and/or the write area within the intermediate 
sl@0: buffer.
sl@0: 
sl@0: A start point is always within an area; an end point is always the first byte 
sl@0: beyond the end of an area.
sl@0: 
sl@0: @param anArea The areas within the intermediate buffer for which the start 
sl@0: and end points are to be set. These can be the read area and/or the write 
sl@0: area, as indicated by the ERead and EWrite bits. Only these bits can be set, 
sl@0: otherwise the function raises a STORE-Stream 17 panic.
sl@0: @param aPtr The start point.
sl@0: @param anEnd The end point.
sl@0: @see MStreamBuf::TRead
sl@0: @see MStreamBuf::TWrite */
sl@0: EXPORT_C void TStreamBuf::SetBuf(TArea anArea,TUint8* aPtr,TUint8* anEnd)
sl@0: 	{
sl@0: 	__ASSERT_ALWAYS(!(anArea&~(ERead|EWrite)),Panic(EStreamAreaInvalid));
sl@0: 	if (anArea&ERead)
sl@0: 		SetBuf(ERead,aPtr,anEnd);
sl@0: 	if (anArea&EWrite)
sl@0: 		SetBuf(EWrite,aPtr,anEnd);
sl@0: 	}
sl@0: 
sl@0: /** Sets the start point of the read and/or the write area within the intermediate 
sl@0: buffer.
sl@0: 
sl@0: A start point is always within an area.
sl@0: 
sl@0: @param anArea The areas within the intermediate buffer for which the start 
sl@0: point is to be set. These can be the read area and/or the write area, as indicated 
sl@0: by the ERead and EWrite bits. Only these bits can be set, otherwise the function 
sl@0: raises a STORE-Stream 17 panic.
sl@0: @param aPtr The start point.
sl@0: @see MStreamBuf::TRead
sl@0: @see MStreamBuf::TWrite */
sl@0: EXPORT_C void TStreamBuf::SetPtr(TArea anArea,TUint8* aPtr)
sl@0: 	{
sl@0: 	__ASSERT_ALWAYS(!(anArea&~(ERead|EWrite)),Panic(EStreamAreaInvalid));
sl@0: 	if (anArea&ERead)
sl@0: 		SetPtr(ERead,aPtr);
sl@0: 	if (anArea&EWrite)
sl@0: 		SetPtr(EWrite,aPtr);
sl@0: 	}
sl@0: 
sl@0: //
sl@0: // Set the end pointer for the buffer area(s) indicated by anArea.
sl@0: //
sl@0: EXPORT_C void TStreamBuf::SetEnd(TArea anArea,TUint8* anEnd)
sl@0: 	{
sl@0: 	__ASSERT_ALWAYS(!(anArea&~(ERead|EWrite)),Panic(EStreamAreaInvalid));
sl@0: 	if (anArea&ERead)
sl@0: 		SetEnd(ERead,anEnd);
sl@0: 	if (anArea&EWrite)
sl@0: 		SetEnd(EWrite,anEnd);
sl@0: 	}
sl@0: 
sl@0: /** Gets the current start point of the read or write area within the intermediate 
sl@0: buffer.
sl@0: 
sl@0: @param anArea The area within the intermediate buffer for which the start 
sl@0: point is to be fetched. This can be either the read area or the write area, 
sl@0: as indicated by the ERead and EWrite bits. Only one of these can be set, otherwise 
sl@0: the function raises a STORE-Stream 17 panic.
sl@0: @return The start point.
sl@0: @see MStreamBuf::TRead
sl@0: @see MStreamBuf::TWrite */
sl@0: EXPORT_C TUint8* TStreamBuf::Ptr(TArea anArea) const
sl@0: 	{
sl@0: 	if (anArea==ERead)
sl@0: 		return Ptr(ERead);
sl@0: //
sl@0: 	__ASSERT_ALWAYS(anArea==EWrite,Panic(EStreamAreaInvalid));
sl@0: 	return Ptr(EWrite);
sl@0: 	}
sl@0: 
sl@0: /** Gets the current end point of the read or write area within the intermediate 
sl@0: buffer.
sl@0: 
sl@0: An end point is always the first byte beyond the end of an area.
sl@0: 
sl@0: @param anArea The area within the intermediate buffer for which the end point 
sl@0: is to be fetched. This can be either the read area or the write area, as indicated 
sl@0: by the ERead and EWrite bits. Only one of these can be set, otherwise the 
sl@0: function raises a STORE-Stream 17 panic.
sl@0: @return The end point. */
sl@0: EXPORT_C TUint8* TStreamBuf::End(TArea anArea) const
sl@0: 	{
sl@0: 	if (anArea==ERead)
sl@0: 		return End(ERead);
sl@0: //
sl@0: 	__ASSERT_ALWAYS(anArea==EWrite,Panic(EStreamAreaInvalid));
sl@0: 	return End(EWrite);
sl@0: 	}
sl@0: 
sl@0: /** Gets the number of bytes available in the read or write area within the intermediate 
sl@0: buffer.
sl@0: 
sl@0: @param anArea The area within the intermediate buffer for which the number 
sl@0: of available bytes is to be fetched. This can be either the read area or the 
sl@0: write area, as indicated by the ERead and EWrite bits. Only one of these can 
sl@0: be set, otherwise the function raises a STORE-Stream 17 panic.
sl@0: @return The number of bytes available. */
sl@0: EXPORT_C TInt TStreamBuf::Avail(TArea anArea) const
sl@0: 	{
sl@0: 	if (anArea==ERead)
sl@0: 		return Avail(ERead);
sl@0: //
sl@0: 	__ASSERT_ALWAYS(anArea==EWrite,Panic(EStreamAreaInvalid));
sl@0: 	return Avail(EWrite);
sl@0: 	}
sl@0: 
sl@0: /** Reads data from the intermediate buffer into the specified memory location.
sl@0: 
sl@0: The function calls the virtual function UnderfLowL() to give concrete implementations 
sl@0: the chance to refill the intermediate buffer, and satisfy the caller's requirements.
sl@0: 
sl@0: This implementation overrides the one supplied by the base class MStreamBuf, 
sl@0: and is called by, MStreamBuf::ReadL(TAny*,TInt).
sl@0: 
sl@0: @param aPtr A pointer to the target memory location for the data read from 
sl@0: the intermediate buffer.
sl@0: @param aMaxLength The maximum number of bytes to be read.
sl@0: @return The number of bytes read. This may be less than the amount requested.
sl@0: @see MStreamBuf::ReadL()
sl@0: @see MStreamBuf::DoReadL() */
sl@0: EXPORT_C TInt TStreamBuf::DoReadL(TAny* aPtr,TInt aMaxLength)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aMaxLength>=0,Panic(EStreamReadLengthNegative));
sl@0: 	__ASSERT_DEBUG(aMaxLength>0,Panic(EStreamReadNoTransfer));
sl@0: 	__ASSERT_DEBUG(Ptr(ERead)!=NULL||End(ERead)==NULL,Panic(EStreamCannotRead));
sl@0: 	TInt left=aMaxLength;
sl@0: 	TInt avail=Avail(ERead);
sl@0: 	__ASSERT_DEBUG(avail>=0,User::Invariant());
sl@0: 	if (avail==0)
sl@0: 		goto underflow;
sl@0: //
sl@0: 	do
sl@0: 		{
sl@0: 		__ASSERT_DEBUG(avail==Avail(ERead),Panic(EStreamUnderflowInBreach));
sl@0: 		__ASSERT_DEBUG(left>0&&avail>0,User::Invariant());
sl@0: 		{
sl@0: 		TInt len=Min(left,avail);
sl@0: 		TUint8* ptr=Ptr(ERead);
sl@0: 		aPtr=Mem::Copy(aPtr,ptr,len);
sl@0: 		SetPtr(ERead,ptr+len);
sl@0: 		left-=len;
sl@0: 		if (left==0)
sl@0: 			return aMaxLength; // that's it
sl@0: 		}
sl@0: //
sl@0: 	underflow:
sl@0: 		avail=UnderflowL(left);
sl@0: 		} while (avail>0);
sl@0: 	__ASSERT_DEBUG(avail==0&&Avail(ERead)==0,Panic(EStreamUnderflowInBreach));
sl@0: 	return aMaxLength-left;
sl@0: 	}
sl@0: 
sl@0: /** Reads data from the intermediate buffer and, if necessary, any remaining data 
sl@0: from the stream to the specified target stream input object.
sl@0: 
sl@0: It is called by ReadL(MStreamInput&,TStreamTransfer).
sl@0: 
sl@0: The intermediate buffer is emptied first by calling the target stream input's 
sl@0: PushL() function, which performs the read from intermediate buffer operation. 
sl@0: Any remaining data is then read from the stream by calling the target stream 
sl@0: object's ReadFromL() function, which performs the read from stream operation.
sl@0: 
sl@0: This implementation is called for streams that have buffering capabilities 
sl@0: and are derived from this class.
sl@0: 
sl@0: @param anInput The target stream input object. 
sl@0: @param aTransfer A stream transfer object defining the amount of data available 
sl@0: to be written.
sl@0: @return The amount of data that was not consumed.
sl@0: @see MStreamInput::ReadFromL()
sl@0: @see MStreamInput::PushL() */
sl@0: EXPORT_C TStreamTransfer TStreamBuf::DoReadL(MStreamInput& anInput,TStreamTransfer aTransfer)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aTransfer>0,Panic(EStreamReadNoTransfer));
sl@0: 	__ASSERT_DEBUG(Ptr(ERead)!=NULL||End(ERead)==NULL,Panic(EStreamCannotRead));
sl@0: 	__ASSERT_DEBUG(Avail(ERead)>=0,User::Invariant());
sl@0: 	TInt len=aTransfer[Avail(ERead)];
sl@0: 	if (len>0)
sl@0: 		{
sl@0: 		__DEBUG(TInt avail=Avail(ERead)); // may be pushing into this streambuf
sl@0: 		TUint8* ptr=Ptr(ERead);
sl@0: 		len=anInput.PushL(ptr,len);
sl@0: 		__ASSERT_DEBUG(len>=0&&len<=aTransfer[avail]&&Ptr(ERead)==ptr&&Avail(ERead)>=avail,Panic(EStreamPushInBreach));
sl@0: 		SetPtr(ERead,ptr+len);
sl@0: 		aTransfer-=len;
sl@0: 		}
sl@0: 	if (aTransfer>0)
sl@0: 		aTransfer=anInput.ReadFromL(*this,aTransfer);
sl@0: 	return aTransfer;
sl@0: 	}
sl@0: 
sl@0: /** Writes data from the specified memory location into the intermediate buffer.
sl@0: 
sl@0: The function calls the virtual function OverfLowL() to give concrete implementations 
sl@0: the chance to forward the intermediate buffer content to its destination.
sl@0: 
sl@0: This implementation overrides the one supplied by the base class MStreamBuf, 
sl@0: and is called by MStreamBuf::WriteL(const TAny*,TInt).
sl@0: 
sl@0: @param aPtr A pointer to the source memory location for the data to be written 
sl@0: to the intermediate buffer.
sl@0: @param aLength The number of bytes to be written.
sl@0: @return The number of bytes written.
sl@0: @see MStreamBuf::WriteL()
sl@0: @see MStreamBuf::DoWriteL() */
sl@0: EXPORT_C void TStreamBuf::DoWriteL(const TAny* aPtr,TInt aLength)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aLength>=0,Panic(EStreamWriteLengthNegative));
sl@0: 	__ASSERT_DEBUG(aLength>0,Panic(EStreamWriteNoTransfer));
sl@0: 	__ASSERT_DEBUG(Ptr(EWrite)!=NULL||End(EWrite)==NULL,Panic(EStreamCannotWrite));
sl@0: 	TInt avail=Avail(EWrite);
sl@0: 	__ASSERT_DEBUG(avail>=0,User::Invariant());
sl@0: 	if (avail==0)
sl@0: 		goto overflow;
sl@0: //
sl@0: 	for(;;)
sl@0: 		{
sl@0: 		__ASSERT_DEBUG(avail>0,Panic(EStreamOverflowInBreach));
sl@0: 		__ASSERT_DEBUG(aLength>0,User::Invariant());
sl@0: 		{
sl@0: 		TInt len=Min(aLength,avail);
sl@0: 		SetPtr(EWrite,Mem::Copy(Ptr(EWrite),aPtr,len));
sl@0: 		aLength-=len;
sl@0: 		if (aLength==0)
sl@0: 			return; // done
sl@0: //
sl@0: 		aPtr=(TUint8*)aPtr+len;
sl@0: 		}
sl@0: //
sl@0: 	overflow:
sl@0: 		OverflowL();
sl@0: 		avail=Avail(EWrite);
sl@0: 		};
sl@0: 	}
sl@0: 
sl@0: //
sl@0: // Default implementation filling the buffer before turning around to anOutput.
sl@0: //
sl@0: EXPORT_C TStreamTransfer TStreamBuf::DoWriteL(MStreamOutput& anOutput,TStreamTransfer aTransfer)
sl@0: 	{
sl@0: 	__ASSERT_DEBUG(aTransfer>0,Panic(EStreamWriteNoTransfer));
sl@0: 	__ASSERT_DEBUG(Ptr(EWrite)!=NULL||End(EWrite)==NULL,Panic(EStreamCannotWrite));
sl@0: 	__ASSERT_DEBUG(Avail(EWrite)>=0,User::Invariant());
sl@0: 	TInt len=aTransfer[Avail(EWrite)];
sl@0: 	if (len>0)
sl@0: 		{
sl@0: 		__DEBUG(TInt avail=Avail(EWrite)); // may be pulling from this streambuf
sl@0: 		TUint8* ptr=Ptr(EWrite);
sl@0: 		len=anOutput.PullL(ptr,len);
sl@0: 		__ASSERT_DEBUG(len>=0&&len<=aTransfer[avail]&&Ptr(EWrite)==ptr&&Avail(EWrite)>=avail,Panic(EStreamPullInBreach));
sl@0: 		SetPtr(EWrite,ptr+len);
sl@0: 		aTransfer-=len;
sl@0: 		}
sl@0: 	if (aTransfer>0)
sl@0: 		aTransfer=anOutput.WriteToL(*this,aTransfer);
sl@0: 	return aTransfer;
sl@0: 	}
sl@0: