// Copyright (c) 2006-2009 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 "rotatingstrbuf.h"

CRotatingStrBuf* CRotatingStrBuf::NewL(TInt aSize)

	{

	CRotatingStrBuf *self = new (ELeave) CRotatingStrBuf;

	CleanupStack::PushL(self);

	self->ConstructL(aSize);

	CleanupStack::Pop();

	return self;

	}

CRotatingStrBuf::~CRotatingStrBuf()

	{

	TEntry* entry;

	while (!iQueue.IsEmpty())

		{

		entry = iQueue.First();

		entry->iLink.Deque();

		delete entry->iText;

		delete entry;

		}

	}

CRotatingStrBuf::CRotatingStrBuf()

	:iQueue(_FOFF(TEntry,iLink))

	{

	}

void CRotatingStrBuf::ConstructL(TInt aSize)

	{

	for(TInt cnt=0; cnt<aSize; cnt++)

		{

		TEntry* entry = new (ELeave) TEntry;

		entry->iText = NULL;

		iQueue.AddLast(*entry);

		}

	}

void CRotatingStrBuf::Put(const TDesC& aText)

	{

	TEntry* entry = iQueue.Last();

	// move last entry to the top of the queue

	entry->iLink.Deque();

	iQueue.AddFirst(*entry);

	// alocate/resize buffer

	if (entry->iText == NULL)

		entry->iText = HBufC::New(aText.Length());

	else if (entry->iText->Des().MaxLength() < aText.Length())

		entry->iText = entry->iText->ReAlloc(aText.Length());

	// copy the text

	if (entry->iText != NULL) // New or ReAlloc may have fail.

		*entry->iText = aText;

	}

HBufC* CRotatingStrBuf::Get()

	{

	TDblQueIter<TEntry> iter(iQueue);

	iter.SetToLast();

	TEntry* entry;

	while ((entry = iter--) != NULL && entry->iText == NULL)

		{};

	if (entry != NULL)

		{

		HBufC* ret = entry->iText;

		entry->iText = NULL;

		return ret;

		}

	return NULL;

	}