template <class T>
GIFDecoder<T>::GIFDecoder(const char *pathFileName)
: LZWDecompression(pathFileName),
  mhGlobalPalette(0),	mlpPaletteData(0), mColors(0), mIsInterlaced(0),
	mBufferCount(0), mPaletteObject(0), mBackgroundObject(0),
	mImageObject(0), mShowObject(0), mErrorObject(0), mPaletteMethod(0),
	mBackgroundMethod(0), mImageMethod(0), mShowMethod(0), mErrorMethod(0)
{
}

template <class T>
GIFDecoder<T>::~GIFDecoder()
{
	if(mhGlobalPalette)
	{
		::GlobalUnlock(mhGlobalPalette);
		::GlobalFree(mhGlobalPalette);
  }
}

template <class T>
WORD GIFDecoder<T>::unpackImage(void)
{
	Index i;
  int hasProcessed;

	hasProcessed=FALSE;
	if(!isOpen())return FALSE;
	if(!getChar())return FALSE;
	if('G'!=currentChar())return FALSE;
	for(i=0;i<5;i++)if(!getChar())return FALSE;
	if(!getWord())return FALSE;
	mScreenWidth=currentWord();
	if(!getWord())return FALSE;
	mScreenHeight=currentWord();
	if(!getChar())return FALSE;
	mGlobalFlagByte=currentChar();
	mColors=1<<((mGlobalFlagByte&0x07)+1);
	if(!getChar())return FALSE;
	mBackgroundColor=currentChar();
	if(!getChar())return FALSE;
	if(currentChar())return FALSE;
	if(mGlobalFlagByte&0x80)
	{
		if(!readPaletteData())return FALSE;
		if(mPaletteObject && mPaletteMethod)
			(mPaletteObject->*mPaletteMethod)(mlpPaletteData,mColors);
	}
	while(TRUE)
	{
		if(!getChar())break;
		switch(currentChar())
		{
			case '!' :   // extension folows
				while(getChar() && currentChar()!=',');
				if(currentChar()!=',')break;
			case ',' :   // image follows
				if(hasProcessed)break;
				hasProcessed=TRUE;
				if(!processImage())return FALSE;
				break;
			case ';' :   // file is completely processed
				continue;
			default :
				return FALSE;
    }
	}
	closeFile();
	return TRUE;
}


template <class T>
WORD GIFDecoder<T>::processImage(void)
{
	UCHAR localFlagByte;

	if(!getWord())return FALSE;
	mImageStartLeft=currentWord();
	if(!getWord())return FALSE;
	mImageStartTop=currentWord();
	if(!getWord())return FALSE;
	mImageWide=currentWord();
	if(!getWord())return FALSE;
	mImageDeep=currentWord();
	if(!getChar())return FALSE;
	localFlagByte=currentChar();
	mIsInterlaced=localFlagByte&0x40;
	mPixelSize=(mGlobalFlagByte&0x07)+1;
	if(localFlagByte&0x80)
	{
		mPixelSize=(localFlagByte&0x07)+1;
		mColors=1<<((localFlagByte&0x07)+1);
		if(!readPaletteData())return FALSE;
		if(mPaletteObject && mPaletteMethod)
			(mPaletteObject->*mPaletteMethod)(mlpPaletteData,mColors);
	}
	if(mBackgroundObject && mBackgroundMethod)
		(mBackgroundObject->*mBackgroundMethod)(mBackgroundColor);
	mBufferCount=0;
	if(!getChar())return FALSE;
	unpackData(mImageWide,mImageDeep,mIsInterlaced,mPixelSize);
	if(mImageObject && mImageMethod)
		(mImageObject->*mImageMethod)();
	return TRUE;
}

template <class T>
WORD GIFDecoder<T>::readPaletteData(void)
{
	if(mhGlobalPalette)
	{
		::GlobalUnlock(mhGlobalPalette);
		::GlobalFree(mhGlobalPalette);
	}
	mhGlobalPalette=::GlobalAlloc(GMEM_FIXED,mColors*3);
	if(!mhGlobalPalette)return FALSE;
	mlpPaletteData=(UCHAR FAR *)::GlobalLock(mhGlobalPalette);
	for(Index i=0;i<mColors*3;i+=3)
	{
		if(!getChar())return FALSE;
		*(mlpPaletteData+i)=currentChar();
		if(!getChar())return FALSE;
		*(mlpPaletteData+i+1)=currentChar();
		if(!getChar())return FALSE;
		*(mlpPaletteData+i+2)=currentChar();
	}
	return TRUE;
}

template <class T>
void GIFDecoder<T>::showHandler(UCHAR FAR *lpOutRow,USHORT yLocation)
{
	if(mShowObject && mShowMethod)
		(mShowObject->*mShowMethod)(mImageWide,mImageDeep,lpOutRow,yLocation);
}

template <class T>
void GIFDecoder<T>::setPaletteHandler(T *object,void (T::*method)(const UCHAR FAR *lpPaletteData,USHORT numColors))
{
	mPaletteObject=object;
	mPaletteMethod=method;
}

template <class T>
void GIFDecoder<T>::setBackgroundHandler(T *object,void (T::*method)(USHORT backgroundColor))
{
	mBackgroundObject=object;
	mBackgroundMethod=method;
}

template <class T>
void GIFDecoder<T>::setImageHandler(T *object,void (T::*method)(void))
{
	mImageObject=object;
	mImageMethod=method;
}

template <class T>
void GIFDecoder<T>::setShowHandler(T *object,void (T::*method)(USHORT imageWide,USHORT imageDeep,const UCHAR FAR *lpRowData,USHORT yLocation))
{
	mShowObject=object;
	mShowMethod=method;
}

template <class T>
void GIFDecoder<T>::setErrorHandler(T *object,void (T::*method)(const char FAR *message))
{
	mErrorObject=object;
	mErrorMethod=method;
}