/*

* Copyright (c) 2010 Ixonos Plc.

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the "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:

* Ixonos Plc

*

* Description:  

*

*/

//

// Jpeg decoder class

#ifndef __CJPEG_H__

#define __CJPEG_H__

#include <e32base.h>

#include <f32file.h>

#include "TBitmapHandle.h"

#include "MJpegLoad.h"

class THuffman;

/// Main Jpeg decode class

class CJpeg

	: public CBase

	, public MJpegLoad

	{

	public:

		static CJpeg* NewL();

		static CJpeg* NewLC();

		~CJpeg();

	private:

		CJpeg();

		void ConstructL();

	public: // MJpegLoad

		void OpenL( const TFileName& aFile );

		void OpenL( const TPtr8& aData );

		void SetScale( TJpegScale aScale );

		TBitmapHandle LoadImageL( TRect& aRect );

		void ScanRandomL();			// scans file, creates random access tables

		TBitmapHandle LoadBlockL( const TPoint& aBlock );

		const TJpegData& Info();

		TPtrC8 ExifData();

	public:

		void EnableRgvConv();

		void DisableRgbConv();

	private:

		inline void BufFwd( TInt aBits );

		inline TInt BufBits( TInt aBits );

		inline TInt Buf16();

		inline void BufLoad8();

		void DecodeBlock();

		void DecodeBlock2();

		void DecodeBlock3();

		void Idct();

		void IdctHalf();

		void CreateHuffmanL( THuffman* aHuffman, const TUint8* aBits, const TUint8* aVal );

		void CreateDefaultHuffmanL();

		void PrepareLoadBlockL();	// must be called before first LoadBlock()

		//

		// Scale load functions:

		//

		void DecRgb1_1L( const TBitmapHandle& aBitmap, const TRect& aBlockRect );

		void DecRgb1_2L( const TBitmapHandle& aBitmap, const TRect& aBlockRect );

		void DecRgb1_4L( const TBitmapHandle& aBitmap, const TRect& aBlockRect );

		void DecRgb1_8L( const TBitmapHandle& aBitmap, const TRect& aBlockRect );

		//

		// Yuv -> Rgb functions

		// 

		// YUV420

		static void Yuv2Rgb22_11_11( TAny* aPtr );

		// YUV422

		static void Yuv2Rgb21_11_11( TAny* aPtr );

		// Any other YUV format

		static void Yuv2RgbFree( TAny* aPtr );

	private:

		/// Jpeg component information struct

		/// one for each color component

		class TComponent

			{

			public:

				char iType;

				char iXFactor;

				char iYFactor;

				char iQuantTable;

				char iID;

			};

		/// Current jpeg block search / use struct

		/// will change to type where the actual huffman data is also contained

		class TJpegBlock

			{

			public:

				TUint32 iOffset;

				TUint32 iBuf;

				TInt iBufBits;

				TInt iY;

				TInt iU;

				TInt iV;

			};

		class TYuvConv

			{

			public:

				TUint32* iRgb;

				TSize iBlkSize;

				TInt iRgbWidth;

				TInt iBlkPixels;

			};

		TUint8* iBuffer;			// contains whole jpeg file now

		TInt iBufPos;

		TUint32 iBuf;				// Huffman bit buffer

		TInt iBufBits;				// number of bits in bitbuffer

		THuffman* iHuffman[ 4 ];	// huffman lookup tables

		TInt iCurrentHuffman;

		TUint8* iQt[ 4 ];			// Quantization tables

		TUint8* iCurrentQt;

		TInt iDct[ 64 ];			// DCT coefficients

		TInt iBlk[ 64 ];			// IDCT result

		TBool iRst;					// RST flag, might occur on some jpegs

		bool iEOF;

		TJpegData iData;

		TComponent iComponent[ 4 ];

		TInt iNumComponents;

		//RArray< TJpegBlock >iBlock;

		TJpegBlock* iBlock;

		TInt		iNumBlocks;

		TUint8* iExifData;

		TInt iExifDataLength;

		// LoadBlock variables:

		TBitmapHandle	iBm;			// rgb block bitmap

		TInt			iBlkPixels;		// number of pixels in rgb block

		TUint8*			iC[ 3 ];		// Y,U,V buffer

		TInt iYxa;

		TInt iYya;

		TInt iUxa;

		TInt iUya;

		TInt iVxa;

		TInt iVya;

		bool iRgbConv;

		//RFs iFs;

		//RFile iDebug;

		TYuvConv iYuvConv;

		void (*iYuv2rgbFunc)(TAny*);

		TInt iImageDataStart;

		bool iRandomScanned;

		bool iLoadBlockPrepared;

		TJpegScale iScale;

		TInt iResetInterval;

	};

inline void CJpeg::BufFwd( TInt aBits )

	{

	iBuf <<= aBits;

	iBufBits -= aBits;

	}

inline TInt CJpeg::BufBits( TInt aBits )

	{

	if( aBits == 0 ) return 0;

	while( iBufBits < aBits )

		{

		BufLoad8();

		}

	TInt val = iBuf >> ( 32-aBits );

	BufFwd( aBits );

	return val;

	}

inline TInt CJpeg::Buf16()

	{

	while( iBufBits < 16 )

		{

		BufLoad8();

		}

	TInt val = iBuf >> ( 32-16 );

	return val;

	}

inline void CJpeg::BufLoad8()

	{

	TInt v;

	v = iBuffer[ iBufPos++ ];

	if( v == 255 )

		{

		v = iBuffer[ iBufPos++ ]; // escaped 0xff ?

		if( v == 0 )

			{

			v = 255;

			}

		else

			{

			//RDebug::Print( _L("Discard %x - position=%d bits=%d"), v, iBufPos, iBufBits );

			// here we have probably discarded a RST0..7

			iRst = ETrue;		// inform decoder of reset

			iBufBits = 255;		// decoder doesn't need any more real data until next mcu

			return;

			}

		}

	v <<= ( 24 - iBufBits );

	iBuf |= v;

	iBufBits += 8;		

	}

#endif