/*

* Copyright (c) 2007 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:  Image Decoder class and observer interface.

*

*/

#ifndef CAM_IMAGEDECODER_H

#define CAM_IMAGEDECODER_H

// ===========================================================================

// Included headers

#include <e32std.h>

#include <f32file.h>

// ===========================================================================

// Forward declarations

class CFbsBitmap;

class CImageDecoder;

class MCameraBuffer;

class CCamBufferShare;

// ===========================================================================

// Classes

/**

* Interface for Image Decoder Observers

*/

class MCamImageDecoderObserver

  {

  public:

    /**

    * Notify observer that the image decoding has finished.

    * @param aStatus Status code describing the success of the operation.

    *        KErrNone if all went as planned.

    * @param aBitmap Decoded bitmap. NULL if errors in decoding.

    */

    virtual void ImageDecoded( TInt aStatus, const CFbsBitmap* aBitmap ) = 0;

  };

/**

* Image Decoder class

*/

class CCamImageDecoder : public CActive

  {

  // =======================================================

  public:

    /**

    * 2-phase constructor.

    */

    static CCamImageDecoder* NewL( MCamImageDecoderObserver& aObserver );

    /**

    * Destructor.

    */

    virtual ~CCamImageDecoder();

  // -------------------------------------------------------

  // From CActive

  protected: 

    /**

    * Called when Cancel is requested and this AO is active.

    * @see CActive

    */

    virtual void DoCancel();

    /**

    * We get notified of the decoding success by a call to RunL

    * when decoding finishes.

    * @see CActive

    */

    virtual void RunL();

    /**

    * If a leave occurs in RunL, RunError gets called by the 

    * Active Scheduler.

    * @param aError Leave code from RunL.

    * @see CActive

    */

    virtual TInt RunError( TInt aError );

  // -------------------------------------------------------

  public:

    void StartConversionL( CCamBufferShare* aBuffer );

  private:

    /**

    * Store the buffer and release any previous buffer.

    * Can be called with NULL to release current buffer.

    */  

    void SetImageData( CCamBufferShare* aBuffer );

    /**

    * Get the image data in descriptor form.

    * No new memory is allocated to the returned buffer,

    * so ownership not transferred.

    * @return Pointer to image data that is to be used for image conversion.

    *         If EXIF thumbnail is available, it is used, otherwise the

    *         full image data is used instead. If the image data cannot be

    *         read from the buffer, or the buffer has not been set,

    *         leave will occur.

    * @leave  KErrNotFound, if image buffer is not set or contains no image data. 

    *         Any other system error, e.g. KErrNoMemory.

    */

    TDesC8* GetImageDataL();

    /**

    * Read the EXIF thumbnail and return it in descriptor.

    * If any errors, return NULL.

    * @param  aExifData The full image data containing EXIF part.

    * @return The EXIF thumbnail in a heap descriptor. NULL if

    *         error occurs in reading (OOM, no data given, 

    *         no EXIF thumbnail found..).

    */

    HBufC8* ReadExifThumbNail( const TDesC8& aExifData );

  private:

    /**

    * 2nd phase constructor.

    */

    void ConstructL();

    /**

    * 1st phase constructor.

    * Cannot leave.

    */

    CCamImageDecoder( MCamImageDecoderObserver& aObserver );

  // =======================================================

  // Data

  private:

    RFs                       iFs;

    MCamImageDecoderObserver& iObserver;

    CCamBufferShare* iSharedImageData;

    HBufC8*          iThumbnailData;

    CFbsBitmap*    iDecodedBitmap;

    CImageDecoder* iDecoder;    

    TInt           iRetryCounter;

  // =======================================================

  };

// ===========================================================================

#endif

// end of file