giffix.c

/*****************************************************************************

giffix - attempt to fix a truncated GIF

SPDX-License-Identifier: MIT

*****************************************************************************/

#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "getarg.h"
#include "gif_lib.h"

#define PROGRAM_NAME "giffix"

static char *VersionStr = PROGRAM_NAME VERSION_COOKIE
    "	Gershon Elber,	" __DATE__ ",   " __TIME__ "\n"
    "(C) Copyright 1989 Gershon Elber.\n";
static char *CtrlStr = PROGRAM_NAME " v%- h%- GifFile!*s";

static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut);

/******************************************************************************
 Interpret the command line and scan the given GIF file.
******************************************************************************/
int main(int argc, char **argv) {
	int i, j, NumFiles, ExtCode, Row, Col, Width, Height, ErrorCode,
	    DarkestColor = 0, ColorIntens = 10000;
	bool Error, HelpFlag = false, GifNoisyPrint = false;
	GifRecordType RecordType;
	GifByteType *Extension;
	char **FileName = NULL;
	GifRowType LineBuffer;
	ColorMapObject *ColorMap;
	GifFileType *GifFileIn = NULL, *GifFileOut = NULL;
	int ImageNum = 0;

	if ((Error = GAGetArgs(argc, argv, CtrlStr, &GifNoisyPrint, &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) {
		(void)fprintf(stderr, VersionStr, GIFLIB_MAJOR, GIFLIB_MINOR);
		GAPrintHowTo(CtrlStr);
		exit(EXIT_SUCCESS);
	}

	if (NumFiles == 1) {
		if ((GifFileIn = DGifOpenFileName(*FileName, &ErrorCode)) ==
		    NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	} else {
		/* Use stdin instead: */
		if ((GifFileIn = DGifOpenFileHandle(0, &ErrorCode)) == NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	}

	/* Open stdout for the output file: */
	if ((GifFileOut = EGifOpenFileHandle(1, &ErrorCode)) == NULL) {
		PrintGifError(ErrorCode);
		exit(EXIT_FAILURE);
	}

	/* Dump out exactly same screen information: */
	/* coverity[var_deref_op] */
	if (EGifPutScreenDesc(GifFileOut, GifFileIn->SWidth, GifFileIn->SHeight,
	                      GifFileIn->SColorResolution,
	                      GifFileIn->SBackGroundColor,
	                      GifFileIn->SColorMap) == GIF_ERROR) {
		QuitGifError(GifFileIn, GifFileOut);
	}

	if ((LineBuffer = (GifRowType)malloc(GifFileIn->SWidth)) == NULL) {
		GIF_EXIT("Failed to allocate memory required, aborted.");
	}

	/* 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.Interlace) {
				GIF_EXIT("Cannot fix interlaced images.");
			}

			Row = GifFileIn->Image
			          .Top; /* Image Position relative to Screen. */
			Col = GifFileIn->Image.Left;
			Width = GifFileIn->Image.Width;
			Height = GifFileIn->Image.Height;
			GifQprintf("\n%s: Image %d at (%d, %d) [%dx%d]:     ",
			           PROGRAM_NAME, ++ImageNum, Col, Row, Width,
			           Height);
			if (Width > GifFileIn->SWidth) {
				GIF_EXIT("Image is wider than total");
			}

			/* Put the image descriptor to out file: */
			if (EGifPutImageDesc(
			        GifFileOut, Col, Row, Width, Height, false,
			        GifFileIn->Image.ColorMap) == GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}

			/* Find the darkest color in color map to use as a
			 * filler. */
			ColorMap = (GifFileIn->Image.ColorMap
			                ? GifFileIn->Image.ColorMap
			                : GifFileIn->SColorMap);
			for (i = 0; i < ColorMap->ColorCount; i++) {
				j = ((int)ColorMap->Colors[i].Red) * 30 +
				    ((int)ColorMap->Colors[i].Green) * 59 +
				    ((int)ColorMap->Colors[i].Blue) * 11;
				if (j < ColorIntens) {
					ColorIntens = j;
					DarkestColor = i;
				}
			}

			/* Load the image, and dump it. */
			for (i = 0; i < Height; i++) {
				GifQprintf("\b\b\b\b%-4d", i);
				if (DGifGetLine(GifFileIn, LineBuffer, Width) ==
				    GIF_ERROR) {
					break;
				}
				if (EGifPutLine(GifFileOut, LineBuffer,
				                Width) == GIF_ERROR) {
					QuitGifError(GifFileIn, GifFileOut);
				}
			}

			if (i < Height) {
				fprintf(stderr, "\nFollowing error occurred "
				                "(and ignored):");
				PrintGifError(GifFileIn->Error);

				/* Fill in with the darkest color in color map.
				 */
				for (j = 0; j < Width; j++) {
					LineBuffer[j] = DarkestColor;
				}
				for (; i < Height; i++) {
					if (EGifPutLine(GifFileOut, LineBuffer,
					                Width) == 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 (Extension != NULL) {
				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);
		exit(EXIT_FAILURE);
	}
	if (EGifCloseFile(GifFileOut, &ErrorCode) == GIF_ERROR) {
		PrintGifError(ErrorCode);
		exit(EXIT_FAILURE);
	}
	return 0;
}

/******************************************************************************
 Close both input and output file (if open), and exit.
******************************************************************************/
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut) {
	fprintf(stderr, "\nFollowing unrecoverable error occurred:");
	if (GifFileIn != NULL) {
		PrintGifError(GifFileIn->Error);
		EGifCloseFile(GifFileIn, NULL);
	}
	if (GifFileOut != NULL) {
		PrintGifError(GifFileOut->Error);
		EGifCloseFile(GifFileOut, NULL);
	}
	exit(EXIT_FAILURE);
}

/* end */