scan.h

// 
// (C) Jan de Vaan 2007-2010, all rights reserved. See the accompanying "License.txt" for licensed use. 
// 

#ifndef CHARLS_SCAN
#define CHARLS_SCAN

#include "lookuptable.h"

// This file contains the code for handling a "scan". Usually an image is encoded as a single scan. 


#ifdef _MSC_VER
#pragma warning (disable: 4127)
#endif


extern CTable decodingTables[16];
extern std::vector<signed char> rgquant8Ll;
extern std::vector<signed char> rgquant10Ll;
extern std::vector<signed char> rgquant12Ll;
extern std::vector<signed char> rgquant16Ll;
//
// Apply 
//
inlinehint LONG ApplySign(LONG i, LONG sign)
{ return (sign ^ i) - sign; }									



// Two alternatives for GetPredictedValue() (second is slightly faster due to reduced branching)

#if 0

inlinehint LONG GetPredictedValue(LONG Ra, LONG Rb, LONG Rc)
{
	if (Ra < Rb)
	{
		if (Rc < Ra)
			return Rb;

		if (Rc > Rb)
			return Ra;
	}
	else
	{
		if (Rc < Rb)
			return Ra;

		if (Rc > Ra)
			return Rb;
	}

	return Ra + Rb - Rc;
}

#else

inlinehint LONG GetPredictedValue(LONG Ra, LONG Rb, LONG Rc)
{
	// sign trick reduces the number of if statements (branches) 
	LONG sgn = BitWiseSign(Rb - Ra);

	// is Ra between Rc and Rb? 
	if ((sgn ^ (Rc - Ra)) < 0)
	{
		return Rb;
	} 
	else if ((sgn ^ (Rb - Rc)) < 0)
	{
		return Ra;
	}

	// default case, valid if Rc element of [Ra,Rb] 
	return Ra + Rb - Rc;
}

#endif

inlinehint LONG UnMapErrVal(LONG mappedError)
{
	//LONG sign = ~((mappedError & 1) - 1);
	LONG sign = LONG(mappedError << (LONG_BITCOUNT-1)) >> (LONG_BITCOUNT-1);
	return sign ^ (mappedError >> 1);
}



inlinehint LONG GetMappedErrVal(LONG Errval)
{
	LONG mappedError = (Errval >> (LONG_BITCOUNT-2)) ^ (2 * Errval);
	return mappedError;
}



inlinehint  LONG ComputeContextID(LONG Q1, LONG Q2, LONG Q3)
{ return (Q1*9 + Q2)*9 + Q3; }


//
//
//
template <class TRAITS, class STRATEGY>
class JlsCodec : public STRATEGY
{
public:
	typedef typename TRAITS::PIXEL PIXEL;
	typedef typename TRAITS::SAMPLE SAMPLE;

public:

	  JlsCodec(const TRAITS& inTraits, const JlsParameters& info) : STRATEGY(info), 
	  traits(inTraits),
		  _rect(),
		  _width(0),
		  T1(0),
		  T2(0),
		  T3(0),
		  _RUNindex(0),
		  _pquant(0),
		  _bCompare(0)
		  
	  {
		  if (Info().ilv == ILV_NONE)
		  {
			  Info().components = 1;
		  }
	  }	


	  void SetPresets(const JlsCustomParameters& presets)
	  {
		  JlsCustomParameters presetDefault = ComputeDefault(traits.MAXVAL, traits.NEAR);

		  InitParams(presets.T1 != 0 ? presets.T1 : presetDefault.T1,
			  presets.T2 != 0 ? presets.T2 : presetDefault.T2,
			  presets.T3 != 0 ? presets.T3 : presetDefault.T3, 
			  presets.RESET != 0 ? presets.RESET : presetDefault.RESET);
	  }	


	  bool IsInterleaved()
	  {
		  if (Info().ilv == ILV_NONE)
			  return false;

		  if (Info().components == 1)
			  return false;

		  return true;
	  }

	  JlsParameters& Info() { return STRATEGY::_info; }

	  signed char QuantizeGratientOrg(LONG Di);
	  inlinehint LONG QuantizeGratient(LONG Di)
	  { 
		  ASSERT(QuantizeGratientOrg(Di) == *(_pquant + Di));
		  return *(_pquant + Di); 
	  }

	  void InitQuantizationLUT();
	
	  LONG DecodeValue(LONG k, LONG limit, LONG qbpp);
	  inlinehint void EncodeMappedValue(LONG k, LONG mappedError, LONG limit);

	  void IncrementRunIndex()
	  { _RUNindex = MIN(31,_RUNindex + 1); }
	  void DecrementRunIndex()
	  { _RUNindex = MAX(0,_RUNindex - 1); }

	  LONG		DecodeRIError(CContextRunMode& ctx);
	  Triplet<SAMPLE> DecodeRIPixel(Triplet<SAMPLE> Ra, Triplet<SAMPLE> Rb);
	  SAMPLE   DecodeRIPixel(LONG Ra, LONG Rb);
	  LONG		DecodeRunPixels(PIXEL Ra, PIXEL* ptype, LONG cpixelMac);
	  LONG		DoRunMode(LONG index, DecoderStrategy*);

	  void	EncodeRIError(CContextRunMode& ctx, LONG Errval);
	  SAMPLE	EncodeRIPixel(LONG x, LONG Ra, LONG Rb);
	  Triplet<SAMPLE> EncodeRIPixel(Triplet<SAMPLE> x, Triplet<SAMPLE> Ra, Triplet<SAMPLE> Rb);
	  void	EncodeRunPixels(LONG runLength, bool bEndofline);
	  LONG		DoRunMode(LONG index, EncoderStrategy*);

	  inlinehint SAMPLE DoRegular(LONG Qs, LONG, LONG pred, DecoderStrategy*);
	  inlinehint SAMPLE DoRegular(LONG Qs, LONG x, LONG pred, EncoderStrategy*);

	  void DoLine(SAMPLE* pdummy);
	  void DoLine(Triplet<SAMPLE>* pdummy);
	  void DoScan(BYTE* compressedBytes, size_t compressedLength);         

public:
	ProcessLine* CreateProcess(void* pvoidOut);
	void InitDefault();
	void InitParams(LONG t1, LONG t2, LONG t3, LONG nReset);

	size_t  EncodeScan(const void* rawData, void* pvoidOut, size_t compressedLength, void* pvoidCompare);
	size_t  DecodeScan(void* rawData, const JlsRect& size, const void* compressedData, size_t compressedLength, bool bCompare);

protected:
	// codec parameters 
	TRAITS traits;
	JlsRect _rect;
	int _width;
	LONG T1;	
	LONG T2;
	LONG T3; 

	// compression context
	JlsContext _contexts[365];	
	CContextRunMode _contextRunmode[2];
	LONG _RUNindex;
	PIXEL* _previousLine; // previous line ptr
	PIXEL* _currentLine; // current line ptr


	// quantization lookup table
	signed char* _pquant;
	std::vector<signed char> _rgquant;

	// debugging
	bool _bCompare;
};


// Encode/decode a single sample. Performancewise the #1 important functions

template<class TRAITS, class STRATEGY>
typename TRAITS::SAMPLE JlsCodec<TRAITS,STRATEGY>::DoRegular(LONG Qs, LONG, LONG pred, DecoderStrategy*)
{		
	LONG sign		= BitWiseSign(Qs);
	JlsContext& ctx	= _contexts[ApplySign(Qs, sign)];
	LONG k			= ctx.GetGolomb();	
	LONG Px			= traits.CorrectPrediction(pred + ApplySign(ctx.C, sign));    

	LONG ErrVal;
	const Code& code		= decodingTables[k].Get(STRATEGY::PeekByte());
	if (code.GetLength() != 0)
	{
		STRATEGY::Skip(code.GetLength());
		ErrVal = code.GetValue(); 
		ASSERT(abs(ErrVal) < 65535);
	}
	else
	{
		ErrVal = UnMapErrVal(DecodeValue(k, traits.LIMIT, traits.qbpp)); 
		if (abs(ErrVal) > 65535)
			throw JlsException(InvalidCompressedData);
	}	
	ErrVal = ErrVal ^ ((traits.NEAR == 0) ? ctx.GetErrorCorrection(k) : 0);
	ctx.UpdateVariables(ErrVal, traits.NEAR, traits.RESET);	
	ErrVal = ApplySign(ErrVal, sign);
	return traits.ComputeReconstructedSample(Px, ErrVal); 
}


template<class TRAITS, class STRATEGY>
typename TRAITS::SAMPLE JlsCodec<TRAITS,STRATEGY>::DoRegular(LONG Qs, LONG x, LONG pred, EncoderStrategy*)
{
	LONG sign		= BitWiseSign(Qs);
	JlsContext& ctx	= _contexts[ApplySign(Qs, sign)];
	LONG k			= ctx.GetGolomb();
	LONG Px			= traits.CorrectPrediction(pred + ApplySign(ctx.C, sign));	

	LONG ErrVal		= traits.ComputeErrVal(ApplySign(x - Px, sign));

	EncodeMappedValue(k, GetMappedErrVal(ctx.GetErrorCorrection(k | traits.NEAR) ^ ErrVal), traits.LIMIT);
	ctx.UpdateVariables(ErrVal, traits.NEAR, traits.RESET);
	ASSERT(traits.IsNear(traits.ComputeReconstructedSample(Px, ApplySign(ErrVal, sign)), x));
	return static_cast<SAMPLE>(traits.ComputeReconstructedSample(Px, ApplySign(ErrVal, sign)));
}


// Functions to build tables used to decode short golomb codes.

inlinehint std::pair<LONG, LONG> CreateEncodedValue(LONG k, LONG mappedError)
{
	LONG highbits = mappedError >> k;
	return std::make_pair(highbits + k + 1, (LONG(1) << k) | (mappedError & ((LONG(1) << k) - 1)));
}


CTable InitTable(LONG k)
{
	CTable table;
	for (short nerr = 0; ; nerr++)
	{		
		// Q is not used when k != 0
		LONG merrval = GetMappedErrVal(nerr);//, k, -1);
		std::pair<LONG, LONG> paircode = CreateEncodedValue(k, merrval);
		if (paircode.first > CTable::cbit)
			break;

		Code code = Code( nerr, short(paircode.first) );
		table.AddEntry(BYTE(paircode.second), code);
	}

	for (short nerr = -1; ; nerr--)
	{		
		// Q is not used when k != 0
		LONG merrval = GetMappedErrVal(nerr);//, k, -1);
		std::pair<LONG, LONG> paircode = CreateEncodedValue(k, merrval);
		if (paircode.first > CTable::cbit)
			break;

		Code code = Code(nerr, short(paircode.first));
		table.AddEntry(BYTE(paircode.second), code);
	}

	return table;
}


// Encoding/decoding of golomb codes

template<class TRAITS, class STRATEGY>
LONG JlsCodec<TRAITS,STRATEGY>::DecodeValue(LONG k, LONG limit, LONG qbpp)
{
	LONG highbits = STRATEGY::ReadHighbits();

	if (highbits >= limit - (qbpp + 1))
		return STRATEGY::ReadValue(qbpp) + 1;

	if (k == 0)
		return highbits;

	return (highbits << k) + STRATEGY::ReadValue(k);
}



template<class TRAITS, class STRATEGY>
inlinehint void JlsCodec<TRAITS,STRATEGY>::EncodeMappedValue(LONG k, LONG mappedError, LONG limit)
{
	LONG highbits = mappedError >> k;

	if (highbits < limit - traits.qbpp - 1)
	{
		if (highbits + 1 > 31)
		{
			STRATEGY::AppendToBitStream(0, highbits / 2);
			highbits = highbits - highbits / 2;													
		}
		STRATEGY::AppendToBitStream(1, highbits + 1);
		STRATEGY::AppendToBitStream((mappedError & ((1 << k) - 1)), k);
		return;
	}

	if (limit - traits.qbpp > 31)
	{
		STRATEGY::AppendToBitStream(0, 31);
		STRATEGY::AppendToBitStream(1, limit - traits.qbpp - 31);			
	}
	else
	{
		STRATEGY::AppendToBitStream(1, limit - traits.qbpp);			
	}
	STRATEGY::AppendToBitStream((mappedError - 1) & ((1 << traits.qbpp) - 1), traits.qbpp);
}


// Sets up a lookup table to "Quantize" sample difference.

template<class TRAITS, class STRATEGY>
void JlsCodec<TRAITS,STRATEGY>::InitQuantizationLUT()
{
	// for lossless mode with default parameters, we have precomputed te luts for bitcounts 8,10,12 and 16 
	if (traits.NEAR == 0 && traits.MAXVAL == (1 << traits.bpp) - 1)
	{
		JlsCustomParameters presets = ComputeDefault(traits.MAXVAL, traits.NEAR);
		if (presets.T1 == T1 && presets.T2 == T2 && presets.T3 == T3)
		{
			if (traits.bpp == 8) 
			{
				_pquant = &rgquant8Ll[rgquant8Ll.size() / 2 ]; 
				return;
			}
			if (traits.bpp == 10) 
			{
				_pquant = &rgquant10Ll[rgquant10Ll.size() / 2 ]; 
				return;
			}			
			if (traits.bpp == 12) 
			{
				_pquant = &rgquant12Ll[rgquant12Ll.size() / 2 ]; 
				return;
			}			
			if (traits.bpp == 16) 
			{
				_pquant = &rgquant16Ll[rgquant16Ll.size() / 2 ]; 
				return;
			}			
		}	
	}

	LONG RANGE = 1 << traits.bpp;

	_rgquant.resize(RANGE * 2);

	_pquant = &_rgquant[RANGE];
	for (LONG i = -RANGE; i < RANGE; ++i)
	{
		_pquant[i] = QuantizeGratientOrg(i);
	}
}


template<class TRAITS, class STRATEGY>
signed char JlsCodec<TRAITS,STRATEGY>::QuantizeGratientOrg(LONG Di)
{
	if (Di <= -T3) return  -4;
	if (Di <= -T2) return  -3;
	if (Di <= -T1) return  -2;
	if (Di < -traits.NEAR)  return  -1;
	if (Di <=  traits.NEAR) return   0;
	if (Di < T1)   return   1;
	if (Di < T2)   return   2;
	if (Di < T3)   return   3;

	return  4;
}



// RI = Run interruption: functions that handle the sample terminating a run.

template<class TRAITS, class STRATEGY>
LONG JlsCodec<TRAITS,STRATEGY>::DecodeRIError(CContextRunMode& ctx)
{
	LONG k = ctx.GetGolomb();
	LONG EMErrval = DecodeValue(k, traits.LIMIT - J[_RUNindex]-1, traits.qbpp);	
	LONG Errval = ctx.ComputeErrVal(EMErrval + ctx._nRItype, k);
	ctx.UpdateVariables(Errval, EMErrval);
	return Errval;
}



template<class TRAITS, class STRATEGY>
void JlsCodec<TRAITS,STRATEGY>::EncodeRIError(CContextRunMode& ctx, LONG Errval)
{
	LONG k			= ctx.GetGolomb();
	bool map		= ctx.ComputeMap(Errval, k);
	LONG EMErrval	= 2 * abs(Errval) - ctx._nRItype - map;	

	ASSERT(Errval == ctx.ComputeErrVal(EMErrval + ctx._nRItype, k));
	EncodeMappedValue(k, EMErrval, traits.LIMIT-J[_RUNindex]-1);
	ctx.UpdateVariables(Errval, EMErrval);
}


template<class TRAITS, class STRATEGY>
Triplet<typename TRAITS::SAMPLE> JlsCodec<TRAITS,STRATEGY>::DecodeRIPixel(Triplet<SAMPLE> Ra, Triplet<SAMPLE> Rb)
{ 
	LONG Errval1 = DecodeRIError(_contextRunmode[0]);
	LONG Errval2 = DecodeRIError(_contextRunmode[0]);
	LONG Errval3 = DecodeRIError(_contextRunmode[0]);

	return Triplet<SAMPLE>(traits.ComputeReconstructedSample(Rb.v1, Errval1 * Sign(Rb.v1  - Ra.v1)),
		traits.ComputeReconstructedSample(Rb.v2, Errval2 * Sign(Rb.v2  - Ra.v2)),
		traits.ComputeReconstructedSample(Rb.v3, Errval3 * Sign(Rb.v3  - Ra.v3)));
}



template<class TRAITS, class STRATEGY>
Triplet<typename TRAITS::SAMPLE> JlsCodec<TRAITS,STRATEGY>::EncodeRIPixel(Triplet<SAMPLE> x, Triplet<SAMPLE> Ra, Triplet<SAMPLE> Rb)
{
	LONG errval1	= traits.ComputeErrVal(Sign(Rb.v1 - Ra.v1) * (x.v1 - Rb.v1));
	EncodeRIError(_contextRunmode[0], errval1);

	LONG errval2	= traits.ComputeErrVal(Sign(Rb.v2 - Ra.v2) * (x.v2 - Rb.v2));
	EncodeRIError(_contextRunmode[0], errval2);

	LONG errval3	= traits.ComputeErrVal(Sign(Rb.v3 - Ra.v3) * (x.v3 - Rb.v3));
	EncodeRIError(_contextRunmode[0], errval3);


	return Triplet<SAMPLE>(traits.ComputeReconstructedSample(Rb.v1, errval1 * Sign(Rb.v1  - Ra.v1)),
		traits.ComputeReconstructedSample(Rb.v2, errval2 * Sign(Rb.v2  - Ra.v2)),
		traits.ComputeReconstructedSample(Rb.v3, errval3 * Sign(Rb.v3  - Ra.v3)));
}



template<class TRAITS, class STRATEGY>
typename TRAITS::SAMPLE JlsCodec<TRAITS,STRATEGY>::DecodeRIPixel(LONG Ra, LONG Rb)
{
	if (abs(Ra - Rb) <= traits.NEAR)
	{
		LONG ErrVal		= DecodeRIError(_contextRunmode[1]);
		return static_cast<SAMPLE>(traits.ComputeReconstructedSample(Ra, ErrVal));
	}
	else
	{
		LONG ErrVal		= DecodeRIError(_contextRunmode[0]);
		return static_cast<SAMPLE>(traits.ComputeReconstructedSample(Rb, ErrVal * Sign(Rb - Ra)));
	}
}


template<class TRAITS, class STRATEGY>
typename TRAITS::SAMPLE JlsCodec<TRAITS,STRATEGY>::EncodeRIPixel(LONG x, LONG Ra, LONG Rb)
{
	if (abs(Ra - Rb) <= traits.NEAR)
	{
		LONG ErrVal	= traits.ComputeErrVal(x - Ra);
		EncodeRIError(_contextRunmode[1], ErrVal);
		return static_cast<SAMPLE>(traits.ComputeReconstructedSample(Ra, ErrVal));
	}
	else
	{
		LONG ErrVal	= traits.ComputeErrVal((x - Rb) * Sign(Rb - Ra));
		EncodeRIError(_contextRunmode[0], ErrVal);
		return static_cast<SAMPLE>(traits.ComputeReconstructedSample(Rb, ErrVal * Sign(Rb - Ra)));
	}
}


// RunMode: Functions that handle run-length encoding

template<class TRAITS, class STRATEGY>
void JlsCodec<TRAITS,STRATEGY>::EncodeRunPixels(LONG runLength, bool endOfLine)
{
	while (runLength >= LONG(1 << J[_RUNindex])) 
	{
		STRATEGY::AppendOnesToBitStream(1);
		runLength = runLength - LONG(1 << J[_RUNindex]);
		IncrementRunIndex();
	}

	if (endOfLine) 
	{
		if (runLength != 0) 
		{
			STRATEGY::AppendOnesToBitStream(1);	
		}
	}
	else
	{
		STRATEGY::AppendToBitStream(runLength, J[_RUNindex] + 1);	// leading 0 + actual remaining length
	}
}


template<class TRAITS, class STRATEGY>
LONG JlsCodec<TRAITS,STRATEGY>::DecodeRunPixels(PIXEL Ra, PIXEL* startPos, LONG cpixelMac)
{
	LONG index = 0;
	while (STRATEGY::ReadBit())
	{
		int count = MIN(1 << J[_RUNindex], int(cpixelMac - index));
		index += count;
		ASSERT(index <= cpixelMac);

		if (count == (1 << J[_RUNindex]))
		{
			IncrementRunIndex();
		}

		if (index == cpixelMac)
			break;
	}


	if (index != cpixelMac)
	{
		// incomplete run 	
		index += (J[_RUNindex] > 0) ? STRATEGY::ReadValue(J[_RUNindex]) : 0;
	}

	if (index > cpixelMac)
		throw JlsException(InvalidCompressedData);

	for (LONG i = 0; i < index; ++i)
	{
		startPos[i] = Ra;
	}	

	return index;
}

template<class TRAITS, class STRATEGY>
LONG JlsCodec<TRAITS,STRATEGY>::DoRunMode(LONG index, EncoderStrategy*)
{
	LONG ctypeRem = _width - index;
	PIXEL* ptypeCurX = _currentLine + index;
	PIXEL* ptypePrevX = _previousLine + index;

	PIXEL Ra = ptypeCurX[-1];

	LONG runLength = 0;

	while (traits.IsNear(ptypeCurX[runLength],Ra)) 
	{
		ptypeCurX[runLength] = Ra;
		runLength++;

		if (runLength == ctypeRem)
			break;
	}

	EncodeRunPixels(runLength, runLength == ctypeRem);

	if (runLength == ctypeRem)
		return runLength;

	ptypeCurX[runLength] = EncodeRIPixel(ptypeCurX[runLength], Ra, ptypePrevX[runLength]);
	DecrementRunIndex();
	return runLength + 1;
}


template<class TRAITS, class STRATEGY>
LONG JlsCodec<TRAITS,STRATEGY>::DoRunMode(LONG startIndex, DecoderStrategy*)
{
	PIXEL Ra = _currentLine[startIndex-1];

	LONG runLength = DecodeRunPixels(Ra, _currentLine + startIndex, _width - startIndex);
	LONG endIndex = startIndex + runLength;

	if (endIndex == _width)
		return endIndex - startIndex;

	// run interruption
	PIXEL Rb = _previousLine[endIndex];
	_currentLine[endIndex] =	DecodeRIPixel(Ra, Rb);
	DecrementRunIndex();
	return endIndex - startIndex + 1;
}


// DoLine: Encodes/Decodes a scanline of samples

template<class TRAITS, class STRATEGY>
void JlsCodec<TRAITS,STRATEGY>::DoLine(SAMPLE*)
{
	LONG index = 0;
	LONG Rb = _previousLine[index-1];
	LONG Rd = _previousLine[index];

	while(index < _width)
	{	
		LONG Ra = _currentLine[index -1];
		LONG Rc = Rb;
		Rb = Rd;
		Rd = _previousLine[index + 1];

		LONG Qs = ComputeContextID(QuantizeGratient(Rd - Rb), QuantizeGratient(Rb - Rc), QuantizeGratient(Rc - Ra));

		if (Qs != 0)
		{
			_currentLine[index] = DoRegular(Qs, _currentLine[index], GetPredictedValue(Ra, Rb, Rc), (STRATEGY*)(NULL));
			index++;
		}
		else
		{
			index += DoRunMode(index, (STRATEGY*)(NULL));
			Rb = _previousLine[index-1];
			Rd = _previousLine[index];	
		}				
	}
}


// DoLine: Encodes/Decodes a scanline of triplets in ILV_SAMPLE mode

template<class TRAITS, class STRATEGY>
void JlsCodec<TRAITS,STRATEGY>::DoLine(Triplet<SAMPLE>*)
{
	LONG index = 0;
	while(index < _width)
	{		
		Triplet<SAMPLE> Ra = _currentLine[index -1];
		Triplet<SAMPLE> Rc = _previousLine[index-1];
		Triplet<SAMPLE> Rb = _previousLine[index];
		Triplet<SAMPLE> Rd = _previousLine[index + 1];

		LONG Qs1 = ComputeContextID(QuantizeGratient(Rd.v1 - Rb.v1), QuantizeGratient(Rb.v1 - Rc.v1), QuantizeGratient(Rc.v1 - Ra.v1));
		LONG Qs2 = ComputeContextID(QuantizeGratient(Rd.v2 - Rb.v2), QuantizeGratient(Rb.v2 - Rc.v2), QuantizeGratient(Rc.v2 - Ra.v2));
		LONG Qs3 = ComputeContextID(QuantizeGratient(Rd.v3 - Rb.v3), QuantizeGratient(Rb.v3 - Rc.v3), QuantizeGratient(Rc.v3 - Ra.v3));

		
		if (Qs1 == 0 && Qs2 == 0 && Qs3 == 0)
		{
			index += DoRunMode(index, (STRATEGY*)(NULL));
		}
		else
		{
			Triplet<SAMPLE> Rx;
			Rx.v1 = DoRegular(Qs1, _currentLine[index].v1, GetPredictedValue(Ra.v1, Rb.v1, Rc.v1), (STRATEGY*)(NULL));
			Rx.v2 = DoRegular(Qs2, _currentLine[index].v2, GetPredictedValue(Ra.v2, Rb.v2, Rc.v2), (STRATEGY*)(NULL));
			Rx.v3 = DoRegular(Qs3, _currentLine[index].v3, GetPredictedValue(Ra.v3, Rb.v3, Rc.v3), (STRATEGY*)(NULL));
			_currentLine[index] = Rx;
			index++;
		}	
	}
}


// DoScan: Encodes or decodes a scan. 
// In ILV_SAMPLE mode, multiple components are handled in DoLine
// In ILV_LINE mode, a call do DoLine is made for every component
// In ILV_NONE mode, DoScan is called for each component 

template<class TRAITS, class STRATEGY>
void JlsCodec<TRAITS,STRATEGY>::DoScan(BYTE* compressedBytes, size_t compressedLength)
{		
	_width = Info().width;

	STRATEGY::Init(compressedBytes, compressedLength);

	LONG pixelstride = _width + 4;
	int components = Info().ilv == ILV_LINE ? Info().components : 1;

	std::vector<PIXEL> vectmp(2 * components * pixelstride);
	std::vector<LONG> rgRUNindex(components);
	
	for (LONG line = 0; line < Info().height; ++line)
	{
		_previousLine			= &vectmp[1];	
		_currentLine			= &vectmp[1 + components * pixelstride];	
		if ((line & 1) == 1)
		{
			std::swap(_previousLine, _currentLine);
		}

		STRATEGY::OnLineBegin(_width, _currentLine, pixelstride);

		for (int component = 0; component < components; ++component)
		{
			_RUNindex = rgRUNindex[component];
		
			// initialize edge pixels used for prediction
			_previousLine[_width]	= _previousLine[_width - 1];
			_currentLine[-1]		= _previousLine[0];
			DoLine((PIXEL*) NULL); // dummy arg for overload resolution
	
			rgRUNindex[component] = _RUNindex;
			_previousLine += pixelstride;
			_currentLine += pixelstride;
		}
		
		if (_rect.Y <= line && line < _rect.Y + _rect.Height)
		{
			STRATEGY::OnLineEnd(_rect.Width, _currentLine + _rect.X - (components * pixelstride), pixelstride);
		}
	}

	STRATEGY::EndScan();
}


// Factory function for ProcessLine objects to copy/transform unencoded pixels to/from our scanline buffers.

template<class TRAITS, class STRATEGY>
ProcessLine* JlsCodec<TRAITS,STRATEGY>::CreateProcess(void* pvoidOut)
{
	if (!IsInterleaved())
		return new PostProcesSingleComponent(pvoidOut, Info(), sizeof(typename TRAITS::PIXEL));

	if (Info().colorTransform == 0)
		return new ProcessTransformed<TransformNone<typename TRAITS::SAMPLE> >(pvoidOut, Info(), TransformNone<SAMPLE>()); 

	if ((Info().bitspersample == sizeof(SAMPLE)*8))
	{
		switch(Info().colorTransform)
		{
			case COLORXFORM_HP1 : return new ProcessTransformed<TransformHp1<SAMPLE> >(pvoidOut, Info(), TransformHp1<SAMPLE>()); break;
			case COLORXFORM_HP2 : return new ProcessTransformed<TransformHp2<SAMPLE> >(pvoidOut, Info(), TransformHp2<SAMPLE>()); break;
			case COLORXFORM_HP3 : return new ProcessTransformed<TransformHp3<SAMPLE> >(pvoidOut, Info(), TransformHp3<SAMPLE>()); break;
			default: throw JlsException(UnsupportedColorTransform);
		}
	} 
	else if (Info().bitspersample > 8)
	{
		int shift = 16 - Info().bitspersample;
		switch(Info().colorTransform)
		{
			case COLORXFORM_HP1 : return new ProcessTransformed<TransformShifted<TransformHp1<USHORT> > >(pvoidOut, Info(), TransformShifted<TransformHp1<USHORT> >(shift)); break;
			case COLORXFORM_HP2 : return new ProcessTransformed<TransformShifted<TransformHp2<USHORT> > >(pvoidOut, Info(), TransformShifted<TransformHp2<USHORT> >(shift)); break;
			case COLORXFORM_HP3 : return new ProcessTransformed<TransformShifted<TransformHp3<USHORT> > >(pvoidOut, Info(), TransformShifted<TransformHp3<USHORT> >(shift)); break;
			default: throw JlsException(UnsupportedColorTransform);
		}
	}
	throw JlsException(UnsupportedBitDepthForTransform);
}



// Setup codec for encoding and calls DoScan

template<class TRAITS, class STRATEGY>
size_t JlsCodec<TRAITS,STRATEGY>::EncodeScan(const void* rawData, void* compressedData, size_t compressedLength, void* pvoidCompare)
{
	STRATEGY::_processLine = std::auto_ptr<ProcessLine>(CreateProcess(const_cast<void*>(rawData)));
	
	BYTE* compressedBytes = static_cast<BYTE*>(compressedData);

	if (pvoidCompare != NULL)
	{
		STRATEGY::_qdecoder = std::auto_ptr<DecoderStrategy>(new JlsCodec<TRAITS,DecoderStrategy>(traits, Info()));		
		STRATEGY::_qdecoder->Init((BYTE*)pvoidCompare, compressedLength); 
	}

	DoScan(compressedBytes, compressedLength);
	
	return	STRATEGY::GetLength();

}

// Setup codec for decoding and calls DoScan

template<class TRAITS, class STRATEGY>
size_t JlsCodec<TRAITS,STRATEGY>::DecodeScan(void* rawData, const JlsRect& rect, const void* compressedData, size_t compressedLength, bool bCompare)
{
	STRATEGY::_processLine = std::auto_ptr<ProcessLine>(CreateProcess(rawData));

	BYTE* compressedBytes	= const_cast<BYTE*>(static_cast<const BYTE*>(compressedData));
	_bCompare = bCompare;

	BYTE rgbyte[20];

	size_t readBytes = 0;
	::memcpy(rgbyte, compressedBytes, 4);
	readBytes += 4;

	size_t cbyteScanheader = rgbyte[3] - 2;

	if (cbyteScanheader > sizeof(rgbyte))
		throw JlsException(InvalidCompressedData);

	::memcpy(rgbyte, compressedBytes, cbyteScanheader);
	readBytes += cbyteScanheader;

	_rect = rect;

	DoScan(compressedBytes + readBytes, compressedLength - readBytes);
	
	return STRATEGY::GetCurBytePos() - compressedBytes;
}

// Initialize the codec data structures. Depends on JPEG-LS parameters like T1-T3.

template<class TRAITS, class STRATEGY>
void JlsCodec<TRAITS,STRATEGY>::InitParams(LONG t1, LONG t2, LONG t3, LONG nReset)
{
	T1 = t1;
	T2 = t2;
	T3 = t3;

	InitQuantizationLUT();

	LONG A = MAX(2, (traits.RANGE + 32)/64);
	for (unsigned int Q = 0; Q < sizeof(_contexts) / sizeof(_contexts[0]); ++Q)
	{
		_contexts[Q] = JlsContext(A);
	}

	_contextRunmode[0] = CContextRunMode(MAX(2, (traits.RANGE + 32)/64), 0, nReset);
	_contextRunmode[1] = CContextRunMode(MAX(2, (traits.RANGE + 32)/64), 1, nReset);
	_RUNindex = 0;
}

#endif