/****************************************************************************

**

** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (developer.feedback@nokia.com)

**

** This file is part of the HbCore module of the UI Extensions for Mobile.

**

** GNU Lesser General Public License Usage

** This file may be used under the terms of the GNU Lesser General Public

** License version 2.1 as published by the Free Software Foundation and

** appearing in the file LICENSE.LGPL included in the packaging of this file.

** Please review the following information to ensure the GNU Lesser General

** Public License version 2.1 requirements will be met:

** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at developer.feedback@nokia.com.

**

****************************************************************************/

#ifndef HB_DEREFERENCER_P_H

#define HB_DEREFERENCER_P_H

#include <QByteArray>

#include <QtGlobal>

#include "hbnvg_p.h"

#include "hbnvgexception_p.h"

class HbDereferencer

{

#define DEREF_PTR(TOTYPE, Offset, Size) do {\

                                checkOutOfBound(Offset + Size); \

                                return * (TOTYPE *)&mReadStream[mTotalRead + Offset];\

                           } while (0)

public:

    HbDereferencer(quint8* buf, qint32 length)

        : mTotalRead(0),

        mDataLength(length),

        mReadStream((unsigned char*)buf)

    {

    }

    HbDereferencer(const QByteArray& buffer)

            : mTotalRead(0),

            mDataLength(buffer.length()),

            mReadStream((unsigned char*)buffer.data())

    {        

    }

    void skip(qint32 length)

    {

        checkOutOfBound(length);

        mTotalRead += length;

    }

    qint16 derefInt16(qint16 at = 0)

    {

        DEREF_PTR(qint16, at, sizeof(qint16));

    }

    operator qint16()

    {

        return derefInt16();    

    }

    qint32 derefInt32(qint32 at = 0)

    {

        DEREF_PTR(qint32, at, sizeof(qint32));

    }

    operator qint32()

    {

        return derefInt32();    

    }

    qint8 derefInt8(qint32 at = 0)

    {

        DEREF_PTR(qint8, at, sizeof(qint8));

    }

    operator qint8()

    {

        return derefInt8();    

    }

    quint8* derefInt8Array(qint32 length, qint32 at = 0)

    {

        checkOutOfBound(at + length);

        return (quint8 *)&mReadStream[mTotalRead + at];

    }

    float derefReal32(qint32 at = 0)

    {

        DEREF_PTR(float, at, sizeof(float));

    }

    operator float()

    {

        return derefReal32();

    }

    void assertBound(qint32 length, qint32 at = 0)

    {

        checkOutOfBound(at + length);

    }

    quint8* getPtr() const

    {

        return mReadStream;

    }

    qint32 getLength() const

    {

        return mDataLength;

    }

    qint32 getReadingPos() const

    {

        return mTotalRead;

    }

private:

    void checkOutOfBound(qint32 length)

    {

        if (mTotalRead + length > mDataLength ||

                mTotalRead + length < 0){

            throw HbNvgException(HbNvgEngine::NvgErrEof);

        }

    }

    qint32                mTotalRead;

    qint32                mDataLength;

    quint8*            mReadStream;

};

#endif