// Copyright (c) 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 "es_commsbuf_internal.h"

__IMPLEMENT_CLEANUP(RCommsBufQ, Free)

EXPORT_C RCommsBufQ::RCommsBufQ(RCommsBuf* aChain)

 	{

	iNext = aChain;

	iLast = RCommsBufChain(aChain).Last(); // Safe even if aChain==NULL

	}

EXPORT_C void RCommsBufQ::Init()

/**

initializes the members

*/

	{

	iNext = NULL;

	iLast = NULL;

	}

EXPORT_C void RCommsBufQ::Assign(RCommsBufQ& aQueue)

/**

Assign this queue to a RCommsBuf queue

@param aQueue to queue

*/

	{

	*this = aQueue;

	aQueue.Init();

	}

EXPORT_C void RCommsBufQ::Assign(RCommsBufChain& aChain)

/**

Assign this a RCommsBuf chain to this queue

@param aChain the chain

*/

 	{

	iNext = aChain.First();

	iLast = aChain.Last();

	aChain.iNext = NULL;

	}

EXPORT_C void RCommsBufQ::Free()

/**

Frees the queue making it empty

*/

	{

	if(iNext)

		iNext->Free();

	Init();

	}

EXPORT_C void RCommsBufQ::Append(RCommsBuf* aBuf)

/**

Appends a RCommsBuf to the queue

@param aBuf the buffer to be prepended

*/

 	{

	if (IsEmpty())

		iNext = iLast = aBuf;

	else

		{

		iLast->SetNext(aBuf);

		iLast = aBuf;

		}

	}

EXPORT_C void RCommsBufQ::Prepend(RCommsBuf* aBuf)

/**

Prepends one RCommsBuf to this queue. aBuf must not point to any further CommsBufs.

@param aBuf the buffer to be appended

*/

	{

    __ASSERT_DEBUG(aBuf->Next()==NULL, CommsBuf::Panic(EMBuf_CannotPrependChainedMBuf));

	if (IsEmpty())

		{

		iNext = aBuf;

		iLast = aBuf;

		aBuf->SetNext(NULL);	// break the mbuf chain (if any)

		}

	else

		{

		aBuf->SetNext(iNext);	// alter the mbuf chain (if any)

		iNext = aBuf;

		}

	}

EXPORT_C void RCommsBufQ::Append(RCommsBufQ& aQueue)

/**

Appends a RCommsBuf queue to this queue

@param aQueue the queue to be appended

*/

 	{

	if (aQueue.IsEmpty())

		return;

	if (IsEmpty())

		{

		// src queue is reset, thus this operation is an append & move

		*this = aQueue;

		aQueue.Init();      // trs; why zero the src queue? implies a move instead of just append.  ideally this should be fixed, but kept as is to avoid a functional break

		}

	else

		{

		// src queue is not altered, thus this operation is only an append (ie. no move)

		iLast->SetNext(aQueue.iNext);

		iLast = aQueue.iLast;

		}

	}

EXPORT_C void RCommsBufQ::Append(RCommsBufChain& aChain)

/**

Appends a RCommsBuf chain to this queue

@param aChain the chain to be appended

*/

 	{

	if (aChain.IsEmpty())

		return;

	if (IsEmpty())

		iNext = aChain.First();

	else

		iLast->SetNext(aChain.First());

	iLast = aChain.Last();

	aChain.iNext = NULL;

	}

EXPORT_C void RCommsBufQ::Prepend(RCommsBufChain& aChain)

/**

Prepends a RCommsBuf chain to this queue

@param aChain the chain to be prepended

*/

 	{

	if (aChain.IsEmpty())

		return;

	if (IsEmpty())

		iLast = aChain.Last();

	else

		aChain.Last()->SetNext(iNext);

	iNext = aChain.First();

	aChain.iNext = NULL;

	}

EXPORT_C void RCommsBufQ::Prepend(RCommsBufQ& aQueue)

/**

Prepends a RCommsBuf queue to this queue

@param aQueue the queue to be prepended

*/

 	{

	if (aQueue.IsEmpty())

		return;

	if (IsEmpty())

		Assign(aQueue);

	else

		{

		aQueue.iLast->SetNext(iNext);

		iNext = aQueue.iNext;

		}

	}

EXPORT_C RCommsBuf* RCommsBufQ::Remove()

/**

Removes the first RCommsBuf from the queue

@return the MBuf

*/

	{

	RCommsBuf* m;

	if (IsEmpty())

		return NULL;

	m = iNext;

	if (iNext = m->Next(), iNext==NULL)

		iLast = NULL;

	m->SetNext(NULL);

	return m;

	}

EXPORT_C TInt RCommsBufQ::Transfer(RCommsBufQ& aQueue, TInt aSize, TInt aBufSize, TInt& aCount)

    {

    __ASSERT_DEBUG(aSize >= 0, CommsBuf::Panic(EMBuf_BadBufferSize));

    TInt transfered = 0;

    aCount = 0;

    if (!IsEmpty())

        {

        RCommsBuf* first;

        RCommsBuf* next;

        RCommsBuf* last;

        first = iNext;

        next = first;

        last = first;

        do 

            {

            ++aCount;

            transfered += aBufSize;

            aSize -= aBufSize;

            last = next;

            next = next->Next();

            } while (aSize > 0 && next != NULL);

        if (next)

            {

            last->SetNext(NULL);

            iNext = next;

            }

        else

            {

            iNext = NULL;

            iLast = NULL;

            }

        RCommsBufQ q(first, last);

        if (aSize < 0)

            {

            q.Last()->AdjustDataEnd(aSize);

            }

        aQueue.Append(q);

        }

    return transfered;

    }

EXPORT_C RCommsBuf* RCommsBufQ::RemoveLast()

    {

    RCommsBuf* current = iNext;

    if(iNext == iLast)

        {

        iNext = iLast = NULL;

        return current;

        }

    while(current->Next() != iLast)

        {

        current = current->Next();

        }

    RCommsBuf* last = iLast;

    current->SetNext(NULL);

    iLast = current;

    return last;

    }