#include <gif/gif.hpp>

GIFDecoder::GIFDecoder(void)
: mhGlobalPalette(0),	mlpPaletteData(0), mColors(0), mIsInterlaced(0), mBufferCount(0)
{
}

GIFDecoder::~GIFDecoder()
{
	if(mhGlobalPalette)
	{
		::GlobalUnlock(mhGlobalPalette);
		::GlobalFree(mhGlobalPalette);
  }
}

WORD GIFDecoder::unpackImage(const char *pathFileName)
{
	int i;
  int hasProcessed;

	hasProcessed=FALSE;
	open(pathFileName);
	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;
		paletteHandler(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;
}

WORD GIFDecoder::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;
		paletteHandler(mlpPaletteData,mColors);
	}
	attributeHandler(mImageWide,mImageDeep,mPixelSize);
	backgroundHandler(mBackgroundColor);
	mBufferCount=0;
	if(!getChar())return FALSE;
	unpackData(mImageWide,mImageDeep,mIsInterlaced,mPixelSize);
	imageHandler();
	return TRUE;
}

WORD GIFDecoder::readPaletteData(void)
{
	if(mhGlobalPalette)
	{
		::GlobalUnlock(mhGlobalPalette);
		::GlobalFree(mhGlobalPalette);
	}
	mhGlobalPalette=::GlobalAlloc(GMEM_FIXED,mColors*3);
	if(!mhGlobalPalette)return FALSE;
	mlpPaletteData=(UCHAR FAR *)::GlobalLock(mhGlobalPalette);
	for(int 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;
}

void GIFDecoder::showHandler(UCHAR FAR *lpOutRow,USHORT yLocation)
{
  showHandler(mImageWide,mImageDeep,lpOutRow,yLocation);
}


// virtuals

void GIFDecoder::paletteHandler(const UCHAR FAR *lpPaletteData,USHORT numColors)
{
}

void GIFDecoder::attributeHandler(USHORT imageWide,USHORT imageDeep,USHORT pixelSize)
{
}

void GIFDecoder::backgroundHandler(USHORT backgroundColor)
{
}

void GIFDecoder::imageHandler(void)
{
}

void GIFDecoder::showHandler(USHORT imageWide,USHORT imageDeep,const UCHAR FAR *lpRowData,USHORT yLocation)
{
}

void GIFDecoder::errorHandler(const char FAR *message)
{
}