自学教程：C++ DGifGetCodeNext函数代码示例

static int DGifGetLine(GifFileType * GifFile, GifPixelType * Line, int LineLen){	GifByteType *Dummy;	GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;	if (!IS_READABLE(Private))	{		_GifError = D_GIF_ERR_NOT_READABLE;		return GIF_ERROR;	}	if (!LineLen)		LineLen = GifFile->Image.Width;	if ((Private->PixelCount -= LineLen) > 0xffff0000UL)	{		_GifError = D_GIF_ERR_DATA_TOO_BIG;		return GIF_ERROR;	}	if (DGifDecompressLine(GifFile, Line, LineLen) == GIF_OK)	{		if (Private->PixelCount == 0)		{			do				if (DGifGetCodeNext(GifFile, &Dummy) == GIF_ERROR)					return GIF_ERROR; while (Dummy != NULL);		}		return GIF_OK;	}	else		return GIF_ERROR;}

/****************************************************************************** Put one pixel (Pixel) into GIF file.******************************************************************************/intDGifGetPixel(GifFileType *GifFile, GifPixelType Pixel){    GifByteType *Dummy;    GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;    if (!IS_READABLE(Private)) {        /* This file was NOT open for reading: */        GifFile->Error = D_GIF_ERR_NOT_READABLE;        return GIF_ERROR;    }    if (--Private->PixelCount > 0xffff0000UL)    {        GifFile->Error = D_GIF_ERR_DATA_TOO_BIG;        return GIF_ERROR;    }    if (DGifDecompressLine(GifFile, &Pixel, 1) == GIF_OK) {        if (Private->PixelCount == 0) {            /* We probably won't be called any more, so let's clean up             * everything before we return: need to flush out all the             * rest of image until an empty block (size 0)             * detected. We use GetCodeNext.	     */            do                if (DGifGetCodeNext(GifFile, &Dummy) == GIF_ERROR)                    return GIF_ERROR;            while (Dummy != NULL) ;        }        return GIF_OK;    } else        return GIF_ERROR;}

/****************************************************************************** Interface for accessing the LZ codes directly. Set Code to the real code (12bits), or to -1 if EOF code is returned.******************************************************************************/intDGifGetLZCodes(GifFileType *GifFile, int *Code){    GifByteType *CodeBlock;    GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;    if (!IS_READABLE(Private)) {        /* This file was NOT open for reading: */        GifFile->Error = D_GIF_ERR_NOT_READABLE;        return GIF_ERROR;    }    if (DGifDecompressInput(GifFile, Code) == GIF_ERROR)        return GIF_ERROR;    if (*Code == Private->EOFCode) {        /* Skip rest of codes (hopefully only NULL terminating block): */        do {            if (DGifGetCodeNext(GifFile, &CodeBlock) == GIF_ERROR)                return GIF_ERROR;        } while (CodeBlock != NULL) ;        *Code = -1;    } else if (*Code == Private->ClearCode) {        /* We need to start over again: */        Private->RunningCode = Private->EOFCode + 1;        Private->RunningBits = Private->BitsPerPixel + 1;        Private->MaxCode1 = 1 << Private->RunningBits;    }    return GIF_OK;}

/****************************************************************************** * Get one full scanned line (Line) of length LineLen from GIF file. *****************************************************************************/static intDGifGetLine(GifFileType * GifFile,            GifPixelType * Line,            int LineLen) {    GifByteType *Dummy;    GifFilePrivateType *Private = GifFile->Private;    if (!LineLen)        LineLen = GifFile->Image.Width;    if ((Private->PixelCount -= LineLen) > 0xffff0000UL) {        return GIF_ERROR;    }    if (DGifDecompressLine(GifFile, Line, LineLen) == GIF_OK) {        if (Private->PixelCount == 0) {            /* We probably would not be called any more, so lets clean             * everything before we return: need to flush out all rest of             * image until empty block (size 0) detected. We use GetCodeNext. */            do                if (DGifGetCodeNext(GifFile, &Dummy) == GIF_ERROR)                    return GIF_ERROR;            while (Dummy != NULL) ;        }        return GIF_OK;    } else        return GIF_ERROR;}

/******************************************************************************* Put one pixel (Pixel) into GIF file.					      *******************************************************************************/int DGifGetPixel(GifFileType *GifFile, GifPixelType *Pixel){    GifByteType *Dummy;    GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;    if (!IS_READABLE(Private)) {	/* This file was NOT open for reading: */	_GifError = D_GIF_ERR_NOT_READABLE;	return GIF_ERROR;    }#if defined(__MSDOS__) || defined(__GNUC__)    if (--Private->PixelCount > 0xffff0000UL)#else    if (--Private->PixelCount > 0xffff0000)#endif /* __MSDOS__ */    {	_GifError = D_GIF_ERR_DATA_TOO_BIG;	return GIF_ERROR;    }    if (DGifDecompressLine(GifFile, Pixel, 1) == GIF_OK) {	if (Private->PixelCount == 0) {	    /* We probably would not be called any more, so lets clean 	     */	    /* everything before we return: need to flush out all rest of    */	    /* image until empty block (size 0) detected. We use GetCodeNext.*/	    do if (DGifGetCodeNext(GifFile, &Dummy) == GIF_ERROR)		return GIF_ERROR;	    while (Dummy != NULL);	}	return GIF_OK;    }    else	return GIF_ERROR;}

//.........这里部分代码省略.........	    QuitGifError(GifFileIn, GifFileOut);	switch (RecordType) {	    case IMAGE_DESC_RECORD_TYPE:		if (DGifGetImageDesc(GifFileIn) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		if ((++ImageNum == ImageN) && ImageNFlag) {		    /* We are suppose to modify this image color map, do it: */		    GifFileIn->SColorMap =ModifyColorMap(GifFileIn->SColorMap);		    if (!HasGIFOutput) {			/* We can quit here, as we have the color map: */			if (GifFileIn != NULL) DGifCloseFile(GifFileIn);			fclose(ColorFile);			exit(EXIT_SUCCESS);		    }		}		if (HasGIFOutput)		    if (EGifPutImageDesc(GifFileOut,			GifFileIn->Image.Left, GifFileIn->Image.Top,			GifFileIn->Image.Width, GifFileIn->Image.Height,			GifFileIn->Image.Interlace,			GifFileIn->Image.ColorMap) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		if (!TranslateFlag || (ImageNFlag && (ImageN != ImageNum)))		{		    /* Now read image itself in decoded form as we don't */		    /* really care what we have there, and this is much  */		    /* faster.						 */		    if (DGifGetCode(GifFileIn, &CodeSize, &CodeBlock) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    if (HasGIFOutput)			if (EGifPutCode(GifFileOut, CodeSize, CodeBlock) == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);		    while (CodeBlock != NULL) {			if (DGifGetCodeNext(GifFileIn, &CodeBlock) == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);			if (HasGIFOutput)			    if (EGifPutCodeNext(GifFileOut, CodeBlock) == GIF_ERROR)				QuitGifError(GifFileIn, GifFileOut);		    }		}		else	/* we need to mung pixels intices */		{		    int	i;		    register GifPixelType *cp;		    GifPixelType *Line			= (GifPixelType *) malloc(GifFileIn->Image.Width *						  sizeof(GifPixelType));		    for (i = 0; i < GifFileIn->Image.Height; i++) {			if (DGifGetLine(GifFileIn, Line,GifFileIn->Image.Width)			    == GIF_ERROR) {			    QuitGifError(GifFileIn, GifFileOut);			}			/* translation step goes here */			for (cp = Line; cp < Line+GifFileIn->Image.Width; cp++)			    *cp = Translation[*cp];			if (EGifPutLine(GifFileOut,					Line, GifFileIn->Image.Width)			    == GIF_ERROR) {			    QuitGifError(GifFileIn, GifFileOut);			}		    }		    free((char *) Line);		}		break;	    case EXTENSION_RECORD_TYPE:		/* Skip any extension blocks in file: */		if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		if (HasGIFOutput)		    if (EGifPutExtension(GifFileOut, ExtCode, Extension[0],							Extension) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		/* No support to more than one extension blocks, so discard: */		while (Extension != NULL) {		    if (DGifGetExtensionNext(GifFileIn, &Extension) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		}		break;	    case TERMINATE_RECORD_TYPE:		break;	    default:		    /* Should be traps by DGifGetRecordType. */		break;	}    }    while (RecordType != TERMINATE_RECORD_TYPE);    if (DGifCloseFile(GifFileIn) == GIF_ERROR)	QuitGifError(GifFileIn, GifFileOut);    if (HasGIFOutput)	if (EGifCloseFile(GifFileOut) == GIF_ERROR)	    QuitGifError(GifFileIn, GifFileOut);    return 0;}

/****************************************************************************** Main sequence******************************************************************************/int main(int argc, char **argv){    GifFileType *GifFileIn = NULL, *GifFileOut = NULL;    GifRecordType RecordType;    int CodeSize, ExtCode, ErrorCode;    GifByteType *CodeBlock, *Extension;    /*     * Command-line processing goes here.     */    /* Use stdin as input (note this also read screen descriptor in: */    if ((GifFileIn = DGifOpenFileHandle(0, &ErrorCode)) == NULL) {	PrintGifError(ErrorCode);	exit(EXIT_FAILURE);    }    /* Use the stdout as output: */    if ((GifFileOut = EGifOpenFileHandle(1, &ErrorCode)) == NULL) {	PrintGifError(ErrorCode);	exit(EXIT_FAILURE);    }    /* And dump out its screen information: */    if (EGifPutScreenDesc(GifFileOut,	GifFileIn->SWidth, GifFileIn->SHeight,	GifFileIn->SColorResolution, GifFileIn->SBackGroundColor,	GifFileIn->SColorMap) == GIF_ERROR)	QuitGifError(GifFileIn, GifFileOut);    /* Scan the content of the input GIF file and load the image(s) in: */    do {	if (DGifGetRecordType(GifFileIn, &RecordType) == GIF_ERROR)	    QuitGifError(GifFileIn, GifFileOut);	switch (RecordType) {	    case IMAGE_DESC_RECORD_TYPE:		if (DGifGetImageDesc(GifFileIn) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		/* Put image descriptor to out file: */		if (EGifPutImageDesc(GifFileOut,		    GifFileIn->Image.Left, GifFileIn->Image.Top,		    GifFileIn->Image.Width, GifFileIn->Image.Height,		    GifFileIn->Image.Interlace,		    GifFileIn->Image.ColorMap) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		/* Now read image itself in decoded form as we dont really   */		/* care what we have there, and this is much faster.	     */		if (DGifGetCode(GifFileIn, &CodeSize, &CodeBlock) == GIF_ERROR ||		    EGifPutCode(GifFileOut, CodeSize, CodeBlock) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		while (CodeBlock != NULL) {		    if (DGifGetCodeNext(GifFileIn, &CodeBlock) == GIF_ERROR ||			EGifPutCodeNext(GifFileOut, CodeBlock) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		}		break;	    case EXTENSION_RECORD_TYPE:		/* pass through extension records */		if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		if (EGifPutExtensionLeader(GifFileOut, ExtCode) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		if (EGifPutExtensionBlock(GifFileOut, 					  Extension[0],					  Extension + 1) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		while (Extension != NULL) {		    if (DGifGetExtensionNext(GifFileIn, &Extension)==GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    if (Extension != NULL)			if (EGifPutExtensionBlock(GifFileOut, 						  Extension[0],						  Extension + 1) == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);		}		if (EGifPutExtensionTrailer(GifFileOut) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		break;	    case TERMINATE_RECORD_TYPE:		break;	    default:	     /* Should be trapped by DGifGetRecordType */		break;	}    }    while (RecordType != TERMINATE_RECORD_TYPE);    if (DGifCloseFile(GifFileIn, &ErrorCode) == GIF_ERROR)    {	PrintGifError(ErrorCode);	if (GifFileIn != NULL) {	    EGifCloseFile(GifFileIn, NULL);	}	exit(EXIT_FAILURE);    }    if (EGifCloseFile(GifFileOut, &ErrorCode) == GIF_ERROR)//.........这里部分代码省略.........

void DDGifSlurp(GifInfo *info, bool shouldDecode) {    GifRecordType RecordType;    GifByteType *ExtData;    int codeSize;    int ExtFunction;    do {        if (DGifGetRecordType(info->gifFilePtr, &RecordType) == GIF_ERROR)            return;        switch (RecordType) {            case IMAGE_DESC_RECORD_TYPE:                if (DGifGetImageDesc(info->gifFilePtr, !shouldDecode) == GIF_ERROR)                    return;                const uint_fast16_t requiredScreenWidth = info->gifFilePtr->Image.Left + info->gifFilePtr->Image.Width;                const uint_fast16_t requiredScreenHeight = info->gifFilePtr->Image.Top + info->gifFilePtr->Image.Height;                if (requiredScreenWidth > info->gifFilePtr->SWidth || requiredScreenHeight > info->gifFilePtr->SHeight) {                    if (shouldDecode) {                        void *tmpRasterBits = realloc(info->rasterBits,                                                      requiredScreenWidth * requiredScreenHeight * sizeof(GifPixelType));                        if (tmpRasterBits == NULL) {                            info->gifFilePtr->Error = D_GIF_ERR_NOT_ENOUGH_MEM;                            return;                        }                        info->rasterBits = tmpRasterBits;                    }                    else {                        info->gifFilePtr->SWidth = requiredScreenWidth;                        info->gifFilePtr->SHeight = requiredScreenHeight;                    }                }                if (shouldDecode) {                    if (info->gifFilePtr->Image.Interlace) {                        uint_fast16_t i, j;                        /*                         * The way an interlaced image should be read -                         * offsets and jumps...                         */                        uint_fast8_t InterlacedOffset[] = {0, 4, 2, 1};                        uint_fast8_t InterlacedJumps[] = {8, 8, 4, 2};                        /* Need to perform 4 passes on the image */                        for (i = 0; i < 4; i++)                            for (j = InterlacedOffset[i]; j < info->gifFilePtr->Image.Height; j += InterlacedJumps[i]) {                                if (DGifGetLine(info->gifFilePtr, info->rasterBits + j * info->gifFilePtr->Image.Width,                                                info->gifFilePtr->Image.Width) == GIF_ERROR)                                    return;                            }                    }                    else {                        if (DGifGetLine(                                info->gifFilePtr, info->rasterBits,                                info->gifFilePtr->Image.Width * info->gifFilePtr->Image.Height) == GIF_ERROR)                            return;                    }                    return;                }                else {                    if (DGifGetCode(info->gifFilePtr, &codeSize, &ExtData) == GIF_ERROR)                        return;                    while (ExtData != NULL) {                        if (DGifGetCodeNext(info->gifFilePtr, &ExtData) == GIF_ERROR)                            return;                    }                }                break;            case EXTENSION_RECORD_TYPE:                if (DGifGetExtension(info->gifFilePtr, &ExtFunction, &ExtData) == GIF_ERROR)                    return;                if (!shouldDecode) {                    GraphicsControlBlock *tmpInfos = realloc(info->controlBlock,                                                             (info->gifFilePtr->ImageCount + 1) *                                                             sizeof(GraphicsControlBlock));                    if (tmpInfos == NULL) {                        info->gifFilePtr->Error = D_GIF_ERR_NOT_ENOUGH_MEM;                        return;                    }                    info->controlBlock = tmpInfos;                    info->controlBlock[info->gifFilePtr->ImageCount].DelayTime = DEFAULT_FRAME_DURATION_MS;                    if (readExtensions(ExtFunction, ExtData, info) == GIF_ERROR)                        return;                }                while (ExtData != NULL) {                    if (DGifGetExtensionNext(info->gifFilePtr, &ExtData,                                             &ExtFunction) == GIF_ERROR)                        return;                    if (!shouldDecode) {                        if (readExtensions(ExtFunction, ExtData, info) == GIF_ERROR)                            return;                    }                }                break;            case TERMINATE_RECORD_TYPE:                break;            default: /* Should be trapped by DGifGetRecordType */                break;//.........这里部分代码省略.........

/******************************************************************************* Perform the disassembly operation - take one input files into few output.   *******************************************************************************/static int DoDisassemblyNum(const char *InFileName, char *OutFileName, int FileNum){    int	ExtCode, CodeSize, FileEmpty;    GifRecordType RecordType;    char CrntFileName[80], *p;    GifByteType *Extension, *CodeBlock;    GifFileType *GifFileIn = NULL, *GifFileOut = NULL;	int ErrorCode;    /* If name has type postfix, strip it out, and make sure name is less    */    /* or equal to 6 chars, so we will have 2 chars in name for numbers.     */    //strupr(OutFileName);		      /* Make sure all is upper case */	#if 0	printf("OutFileName : %s/n", OutFileName);	if ((p = strrchr(OutFileName, '.')) != NULL && strlen(p) <= 4) p[0] = 0;    if ((p = strrchr(OutFileName, '/')) != NULL ||	(p = strrchr(OutFileName, '//')) != NULL ||	(p = strrchr(OutFileName, ':')) != NULL) {	if (strlen(p) > 7) p[7] = 0;   /* p includes the '/', '//', ':' char */    }    else {	/* Only name is given for current directory: */	//if (strlen(OutFileName) > 6) OutFileName[6] = 0;    }	printf("OutFileName : %s/n", OutFileName);	#endif    /* Open input file: */    if (InFileName != NULL) {	if ((GifFileIn = DGifOpenFileName(InFileName, &ErrorCode)) == NULL)	    return QuitGifError(GifFileIn, GifFileOut);    }    else {	/* Use the stdin instead: */	if ((GifFileIn = DGifOpenFileHandle(0, &ErrorCode)) == NULL)	    return QuitGifError(GifFileIn, GifFileOut);    }    /* Scan the content of GIF file and dump image(s) to seperate file(s): */	//sprintf(CrntFileName, "%s_%02d.gif", OutFileName, FileNum);	sprintf(CrntFileName, "%s", OutFileName);	if ((GifFileOut = EGifOpenFileName(CrntFileName, TRUE, &ErrorCode)) == NULL)	    return QuitGifError(GifFileIn, GifFileOut);	FileEmpty = TRUE;	/* And dump out its exactly same screen information: */	if (EGifPutScreenDesc(GifFileOut,	    GifFileIn->SWidth, GifFileIn->SHeight,	    GifFileIn->SColorResolution, GifFileIn->SBackGroundColor,	    GifFileIn->SColorMap) == GIF_ERROR)	    return QuitGifError(GifFileIn, GifFileOut);	do {	    if (DGifGetRecordType(GifFileIn, &RecordType) == GIF_ERROR)			return QuitGifError(GifFileIn, GifFileOut);	    switch (RecordType) {		case IMAGE_DESC_RECORD_TYPE:		    FileEmpty = FALSE;		    if (DGifGetImageDesc(GifFileIn) == GIF_ERROR)				return QuitGifError(GifFileIn, GifFileOut);		    /* Put same image descriptor to out file: */		    if (EGifPutImageDesc(GifFileOut,			GifFileIn->Image.Left, GifFileIn->Image.Top,			GifFileIn->Image.Width, GifFileIn->Image.Height,			GifFileIn->Image.Interlace,			GifFileIn->Image.ColorMap) == GIF_ERROR)				return QuitGifError(GifFileIn, GifFileOut);		    /* Now read image itself in decoded form as we dont      */		    /* really care what is there, and this is much faster.   */		    if (DGifGetCode(GifFileIn, &CodeSize, &CodeBlock) == GIF_ERROR		     || EGifPutCode(GifFileOut, CodeSize, CodeBlock) == GIF_ERROR)				return QuitGifError(GifFileIn, GifFileOut);		    while (CodeBlock != NULL)			if (DGifGetCodeNext(GifFileIn, &CodeBlock) == GIF_ERROR ||			    EGifPutCodeNext(GifFileOut, CodeBlock) == GIF_ERROR)				return QuitGifError(GifFileIn, GifFileOut);		    break;		case EXTENSION_RECORD_TYPE:		    FileEmpty = FALSE;		    /* Skip any extension blocks in file: */		    if (DGifGetExtension(GifFileIn, &ExtCode, &Extension)			== GIF_ERROR)				return QuitGifError(GifFileIn, GifFileOut);		    if (EGifPutExtension(GifFileOut, ExtCode, Extension[0],							Extension) == GIF_ERROR)				return QuitGifError(GifFileIn, GifFileOut);		    /* No support to more than one extension blocks, discard */		    while (Extension != NULL)			if (DGifGetExtensionNext(GifFileIn, &Extension)			    == GIF_ERROR)			    return QuitGifError(GifFileIn, GifFileOut);		    break;		case TERMINATE_RECORD_TYPE:		    break;//.........这里部分代码省略.........

/******************************************************************************* Perform the assembly operation - take few input files into one output.      *******************************************************************************/static void DoAssembly(int NumFiles, char **FileNames){    int	i, ExtCode, CodeSize;    GifRecordType RecordType;    GifByteType *Extension, *CodeBlock;    GifFileType *GifFileIn = NULL, *GifFileOut = NULL;    /* Open stdout for the output file: */    if ((GifFileOut = EGifOpenFileHandle(1)) == NULL)	QuitGifError(GifFileIn, GifFileOut);    /* Scan the content of the GIF file and load the image(s) in: */    for (i = 0; i < NumFiles; i++) {	if ((GifFileIn = DGifOpenFileName(FileNames[i])) == NULL)	    QuitGifError(GifFileIn, GifFileOut);	/* And dump out screen descriptor iff its first image.	*/	if (i == 0)	    if (EGifPutScreenDesc(GifFileOut,		GifFileIn -> SWidth, GifFileIn -> SHeight,		GifFileIn -> SColorResolution, GifFileIn -> SBackGroundColor,		GifFileIn -> SBitsPerPixel, GifFileIn -> SColorMap) == GIF_ERROR)		QuitGifError(GifFileIn, GifFileOut);	do {	    if (DGifGetRecordType(GifFileIn, &RecordType) == GIF_ERROR)		QuitGifError(GifFileIn, GifFileOut);	    switch (RecordType) {		case IMAGE_DESC_RECORD_TYPE:		    if (DGifGetImageDesc(GifFileIn) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    /* Put image descriptor to out file: */		    if (EGifPutImageDesc(GifFileOut,			GifFileIn -> ILeft, GifFileIn -> ITop,			GifFileIn -> IWidth, GifFileIn -> IHeight,			GifFileIn -> IInterlace, GifFileIn -> IBitsPerPixel,			GifFileIn -> IColorMap) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    /* Now read image itself in decoded form as we dont      */		    /* dont care what is there, and this is much faster.     */		    if (DGifGetCode(GifFileIn, &CodeSize, &CodeBlock) == GIF_ERROR		     || EGifPutCode(GifFileOut, CodeSize, CodeBlock) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    while (CodeBlock != NULL)			if (DGifGetCodeNext(GifFileIn, &CodeBlock) == GIF_ERROR ||			    EGifPutCodeNext(GifFileOut, CodeBlock) == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);		    break;		case EXTENSION_RECORD_TYPE:		    /* Skip any extension blocks in file: */		    if (DGifGetExtension(GifFileIn, &ExtCode, &Extension)			== GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    if (EGifPutExtension(GifFileOut, ExtCode, Extension[0],						       Extension) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    /* No support to more than one extension blocks, discard.*/		    while (Extension != NULL)			if (DGifGetExtensionNext(GifFileIn, &Extension)			    == GIF_ERROR)				QuitGifError(GifFileIn, GifFileOut);		    break;		case TERMINATE_RECORD_TYPE:		    break;		default:	    /* Should be traps by DGifGetRecordType. */		    break;	    }	}	while (RecordType != TERMINATE_RECORD_TYPE);	if (DGifCloseFile(GifFileIn) == GIF_ERROR)	    QuitGifError(GifFileIn, GifFileOut);    }    if (EGifCloseFile(GifFileOut) == GIF_ERROR)	QuitGifError(GifFileIn, GifFileOut);}

//.........这里部分代码省略.........			}			GifQprintf("/b/b/b/b%-4d", i);		    }		    /* Clip the lines from ImageY1 to ImageY2 (to X1 - X2): */		    for (i = ImageY1; i <= ImageY2; i++) {			if (DGifGetLine(GifFileIn, Line, GifFileIn->Image.Width)			    == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);			if (!Complement)			    if (EGifPutLine(GifFileOut, &Line[ImageX1],					    ImageWidth) == GIF_ERROR)				QuitGifError(GifFileIn, GifFileOut);			GifQprintf("/b/b/b/b%-4d", i);		    }		    /* Skip lines above ImageY2: */		    for (i = ImageY2 + 1; i < GifFileIn->Image.Height; i++) {			if (DGifGetLine(GifFileIn, Line, GifFileIn->Image.Width)			    == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);			if (Complement) {			    if (ImageX1 == ImageX2) {				/* don't remove any vertical band */				if (EGifPutLine(GifFileOut, Line,						ImageWidth) == GIF_ERROR)				    QuitGifError(GifFileIn, GifFileOut);			    }			    else			    {				if (EGifPutLine(GifFileOut, Line,						ImageX1) == GIF_ERROR)				    QuitGifError(GifFileIn, GifFileOut);				if (EGifPutLine(GifFileOut,						&Line[ImageX2 + 1],						GifFileIn->SWidth - (ImageX2 + 1)						) == GIF_ERROR)				    QuitGifError(GifFileIn, GifFileOut);			    }			}			GifQprintf("/b/b/b/b%-4d", i);		    }		    free((char *) Line);		}		else {		    /* Copy the image as is (we dont modify this one): */		    if (EGifPutImageDesc(GifFileOut,			GifFileIn->Image.Left, GifFileIn->Image.Top,			GifFileIn->Image.Width, GifFileIn->Image.Height,			GifFileIn->Image.Interlace,			GifFileIn->Image.ColorMap) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    /* Now read image itself in decoded form as we dont      */		    /* really care what is there, and this is much faster.   */		    if (DGifGetCode(GifFileIn, &CodeSize, &CodeBlock) == GIF_ERROR		     || EGifPutCode(GifFileOut, CodeSize, CodeBlock) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    while (CodeBlock != NULL)			if (DGifGetCodeNext(GifFileIn, &CodeBlock) == GIF_ERROR ||			    EGifPutCodeNext(GifFileOut, CodeBlock) == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);		}		break;	    case EXTENSION_RECORD_TYPE:		/* Skip any extension blocks in file: */		if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		if (EGifPutExtension(GifFileOut, ExtCode, Extension[0],							Extension) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		/* No support to more than one extension blocks, so discard: */		while (Extension != NULL) {		    if (DGifGetExtensionNext(GifFileIn, &Extension) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		}		break;	    case TERMINATE_RECORD_TYPE:		break;	    default:		    /* Should be traps by DGifGetRecordType. */		break;	}    }    while (RecordType != TERMINATE_RECORD_TYPE);    if (DGifCloseFile(GifFileIn) == GIF_ERROR)	QuitGifError(GifFileIn, GifFileOut);    if (EGifCloseFile(GifFileOut) == GIF_ERROR)	QuitGifError(GifFileIn, GifFileOut);    return 0;}

void DDGifSlurp(GifInfo *info, bool decode, bool exitAfterFrame) {	GifRecordType RecordType;	GifByteType *ExtData;	int ExtFunction;	GifFileType *gifFilePtr;	gifFilePtr = info->gifFilePtr;	uint_fast32_t lastAllocatedGCBIndex = 0;	do {		if (DGifGetRecordType(gifFilePtr, &RecordType) == GIF_ERROR)			return;		bool isInitialPass = !decode && !exitAfterFrame;		switch (RecordType) {			case IMAGE_DESC_RECORD_TYPE:				if (DGifGetImageDesc(gifFilePtr, isInitialPass) == GIF_ERROR)					return;				if (isInitialPass) {					int_fast32_t widthOverflow = gifFilePtr->Image.Width - gifFilePtr->SWidth;					int_fast32_t heightOverflow = gifFilePtr->Image.Height - gifFilePtr->SHeight;					if (widthOverflow > 0 || heightOverflow > 0) {						gifFilePtr->SWidth += widthOverflow;						gifFilePtr->SHeight += heightOverflow;					}					SavedImage *sp = &gifFilePtr->SavedImages[gifFilePtr->ImageCount - 1];					int_fast32_t topOverflow = gifFilePtr->Image.Top + gifFilePtr->Image.Height - gifFilePtr->SHeight;					if (topOverflow > 0) {						sp->ImageDesc.Top -= topOverflow;					}					int_fast32_t leftOverflow = gifFilePtr->Image.Left + gifFilePtr->Image.Width - gifFilePtr->SWidth;					if (leftOverflow > 0) {						sp->ImageDesc.Left -= leftOverflow;					}					if (!updateGCB(info, &lastAllocatedGCBIndex)) {						return;					}				}				if (decode) {					int_fast32_t widthOverflow = gifFilePtr->Image.Width - info->originalWidth;					int_fast32_t heightOverflow = gifFilePtr->Image.Height - info->originalHeight;					if (widthOverflow > 0 || heightOverflow > 0) {						void *tmpRasterBits = reallocarray(info->rasterBits, info->originalWidth * info->originalHeight, sizeof(GifPixelType));						if (tmpRasterBits == NULL) {							gifFilePtr->Error = D_GIF_ERR_NOT_ENOUGH_MEM;							return;						}						info->rasterBits = tmpRasterBits;					}					if (gifFilePtr->Image.Interlace) {						uint_fast16_t i, j;						/*						 * The way an interlaced image should be read -						 * offsets and jumps...						 */						uint_fast8_t InterlacedOffset[] = {0, 4, 2, 1};						uint_fast8_t InterlacedJumps[] = {8, 8, 4, 2};						/* Need to perform 4 passes on the image */						for (i = 0; i < 4; i++)							for (j = InterlacedOffset[i]; j < gifFilePtr->Image.Height; j += InterlacedJumps[i]) {								if (DGifGetLine(gifFilePtr, info->rasterBits + j * gifFilePtr->Image.Width, gifFilePtr->Image.Width) == GIF_ERROR)									return;							}					} else {						if (DGifGetLine(gifFilePtr, info->rasterBits, gifFilePtr->Image.Width * gifFilePtr->Image.Height) == GIF_ERROR) {							return;						}					}					if (info->sampleSize > 1) {						unsigned char *dst = info->rasterBits;						unsigned char *src = info->rasterBits;						unsigned char *const srcEndImage = info->rasterBits + gifFilePtr->Image.Width * gifFilePtr->Image.Height;						do {							unsigned char *srcNextLineStart = src + gifFilePtr->Image.Width * info->sampleSize;							unsigned char *const srcEndLine = src + gifFilePtr->Image.Width;							unsigned char *dstEndLine = dst + gifFilePtr->Image.Width / info->sampleSize;							do {								*dst = *src;								dst++;								src += info->sampleSize;							} while (src < srcEndLine);							dst = dstEndLine;							src = srcNextLineStart;						} while (src < srcEndImage);					}					return;				} else {					do {						if (DGifGetCodeNext(gifFilePtr, &ExtData) == GIF_ERROR) {							return;						}					} while (ExtData != NULL);					if (exitAfterFrame) {						return;					}				}				break;//.........这里部分代码省略.........

/******************************************************************************* Interpret the command line and scan the given GIF file.		      *******************************************************************************/int main(int argc, char **argv){    int	i, j, Size, Error, NumFiles, ExtCode, CodeSize, NumColors = 2, Color,	Count, ImageNum = 0, TextFlag = FALSE, SizeFlag = FALSE,	ImageNFlag = FALSE, BackGroundFlag = FALSE, HelpFlag = FALSE;    long Scaler, Histogram[256];    GifRecordType RecordType;    GifByteType *Extension, *CodeBlock;    char **FileName = NULL;    GifRowType Line;    GifFileType *GifFileIn = NULL, *GifFileOut = NULL;    /* Same image dimension vars for both Image & ImageN as only one allowed */    if ((Error = GAGetArgs(argc, argv, CtrlStr, &GifQuietPrint,		&TextFlag, &SizeFlag, &ImageWidth, &ImageHeight,		&ImageNFlag, &ImageN, &BackGroundFlag,		&HelpFlag, &NumFiles, &FileName)) != FALSE ||		(NumFiles > 1 && !HelpFlag)) {	if (Error)	    GAPrintErrMsg(Error);	else if (NumFiles > 1)	    GIF_MESSAGE("Error in command line parsing - one GIF file please.");	GAPrintHowTo(CtrlStr);	exit(EXIT_FAILURE);    }    if (HelpFlag) {	fprintf(stderr, VersionStr);	GAPrintHowTo(CtrlStr);	exit(EXIT_SUCCESS);    }    if (NumFiles == 1) {	if ((GifFileIn = DGifOpenFileName(*FileName)) == NULL)	    QuitGifError(GifFileIn, GifFileOut);    }    else {	/* Use the stdin instead: */	if ((GifFileIn = DGifOpenFileHandle(0)) == NULL)	    QuitGifError(GifFileIn, GifFileOut);    }    for (i = 0; i < 256; i++) Histogram[i] = 0;		  /* Reset counters. */    /* Scan the content of the GIF file and load the image(s) in: */    do {	if (DGifGetRecordType(GifFileIn, &RecordType) == GIF_ERROR)	    QuitGifError(GifFileIn, GifFileOut);	switch (RecordType) {	    case IMAGE_DESC_RECORD_TYPE:		if (DGifGetImageDesc(GifFileIn) == GIF_ERROR)		    QuitGifError(GifFileIn, GifFileOut);		if (GifFileIn->Image.ColorMap)		    NumColors = GifFileIn->Image.ColorMap->ColorCount;		else if (GifFileIn->SColorMap)		    NumColors = GifFileIn->SColorMap->ColorCount;		else		    GIF_EXIT("Neither Screen nor Image color map exists.");		if ((ImageHeight / NumColors) * NumColors != ImageHeight)		    GIF_EXIT("Image height specified not dividable by #colors.");		if (++ImageNum == ImageN) {		    /* This is the image we should make histogram for:       */		    Line = (GifRowType) malloc(GifFileIn->Image.Width *							sizeof(GifPixelType));		    GifQprintf("/n%s: Image %d at (%d, %d) [%dx%d]:     ",			PROGRAM_NAME, ImageNum,			GifFileIn->Image.Left, GifFileIn->Image.Top,			GifFileIn->Image.Width, GifFileIn->Image.Height);		    for (i = 0; i < GifFileIn->Image.Height; i++) {			if (DGifGetLine(GifFileIn, Line, GifFileIn->Image.Width)			    == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);			for (j = 0; j < GifFileIn->Image.Width; j++)			    Histogram[Line[j]]++;			GifQprintf("/b/b/b/b%-4d", i);		    }		    free((char *) Line);		}		else {		    /* Skip the image: */		    /* Now read image itself in decoded form as we dont      */		    /* really care what is there, and this is much faster.   */		    if (DGifGetCode(GifFileIn, &CodeSize, &CodeBlock) == GIF_ERROR)			QuitGifError(GifFileIn, GifFileOut);		    while (CodeBlock != NULL)			if (DGifGetCodeNext(GifFileIn, &CodeBlock) == GIF_ERROR)			    QuitGifError(GifFileIn, GifFileOut);		}		break;	    case EXTENSION_RECORD_TYPE:		/* Skip any extension blocks in file: *///.........这里部分代码省略.........

//.........这里部分代码省略.........			printf(", BitsPerPixel = %d./n",				GifFile->Image.ColorMap->BitsPerPixel);		    else			printf("./n");		    if (GifFile->Image.ColorMap)			printf("/tImage Has Color Map./n");		    else			printf("/tNo Image Color Map./n");		    if (ColorMapFlag && GifFile->Image.ColorMap) {			printf("/tSort Flag: %s/n", 			       GifFile->Image.ColorMap->SortFlag ? "on":"off");			Len = 1 << GifFile->Image.ColorMap->BitsPerPixel;			for (i = 0; i < Len; i+=4) {			    for (j = 0; j < 4 && j < Len; j++) {				printf("%3d: %02xh %02xh %02xh   ", i + j,				       GifFile->Image.ColorMap->Colors[i + j].Red,				       GifFile->Image.ColorMap->Colors[i + j].Green,				       GifFile->Image.ColorMap->Colors[i + j].Blue);			    }			    printf("/n");			}		    }		}		if (EncodedFlag) {		    if (DGifGetCode(GifFile, &CodeSize, &CodeBlock) == GIF_ERROR) {			PrintGifError(GifFile->Error);			exit(EXIT_FAILURE);		    }		    printf("/nImage LZ compressed Codes (Code Size = %d):/n",			   CodeSize);		    PrintCodeBlock(GifFile, CodeBlock, true);		    while (CodeBlock != NULL) {			if (DGifGetCodeNext(GifFile, &CodeBlock) == GIF_ERROR) {			    PrintGifError(GifFile->Error);			    exit(EXIT_FAILURE);			}			PrintCodeBlock(GifFile, CodeBlock, false);		    }		}		else if (LZCodesFlag) {		    PrintLZCodes(GifFile);		}		else if (PixelFlag) {		    Line = (GifPixelType *) malloc(GifFile->Image.Width *						sizeof(GifPixelType));		    for (i = 0; i < GifFile->Image.Height; i++) {			if (DGifGetLine(GifFile, Line, GifFile->Image.Width)			    == GIF_ERROR) {			    PrintGifError(GifFile->Error);			    exit(EXIT_FAILURE);			}			PrintPixelBlock(Line, GifFile->Image.Width, i == 0);		    }		    PrintPixelBlock(NULL, GifFile->Image.Width, false);		    free((char *) Line);		}		else if (RawFlag) {		    Line = (GifPixelType *) malloc(GifFile->Image.Width *						sizeof(GifPixelType));		    for (i = 0; i < GifFile->Image.Height; i++) {			if (DGifGetLine(GifFile, Line, GifFile->Image.Width)			    == GIF_ERROR) {			    PrintGifError(GifFile->Error);			    exit(EXIT_FAILURE);			}

/*******************************************************************************  Get one full scanned line (Line) of length LineLen from GIF file.	      *******************************************************************************/int DGifGetLine(GifFileType *GifFile, GifPixelType *Line, int LineLen){    GifByteType *Dummy;    GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;    if (!IS_READABLE(Private)) {	/* This file was NOT open for reading: */	_GifError = D_GIF_ERR_NOT_READABLE;	return GIF_ERROR;    }    if (!LineLen) LineLen = GifFile->Image.Width;#if defined(__MSDOS__) || defined(__GNUC__)    if ((Private->PixelCount -= LineLen) > 0xffff0000UL) {#else    if ((Private->PixelCount -= LineLen) > 0xffff0000) {#endif /* __MSDOS__ */	_GifError = D_GIF_ERR_DATA_TOO_BIG;	return GIF_ERROR;    }    if (DGifDecompressLine(GifFile, Line, LineLen) == GIF_OK) {	if (Private->PixelCount == 0) {	    /* We probably would not be called any more, so lets clean 	     */	    /* everything before we return: need to flush out all rest of    */	    /* image until empty block (size 0) detected. We use GetCodeNext.*/	    do if (DGifGetCodeNext(GifFile, &Dummy) == GIF_ERROR)		return GIF_ERROR;	    while (Dummy != NULL);	}	return GIF_OK;    }    else	return GIF_ERROR;}/*******************************************************************************   Get an extension block (see GIF manual) from gif file. This routine only  ** returns the first data block, and DGifGetExtensionNext shouldbe called      ** after this one until NULL extension is returned.			      **   The Extension should NOT be freed by the user (not dynamically allocated).**   Note it is assumed the Extension desc. header ('!') has been read.	      *******************************************************************************/int DGifGetExtension(GifFileType *GifFile, int *ExtCode,						    GifByteType **Extension){    GifByteType Buf;    GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;    if (!IS_READABLE(Private)) {	/* This file was NOT open for reading: */	_GifError = D_GIF_ERR_NOT_READABLE;	return GIF_ERROR;    }    if (READ(GifFile,&Buf, 1) != 1) {	_GifError = D_GIF_ERR_READ_FAILED;	return GIF_ERROR;    }    *ExtCode = Buf;    return DGifGetExtensionNext(GifFile, Extension);}