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/*
* Skeleton file for generic GIF `filter' program --- sequentially read GIF
* records from stdin, process them, send them out. Most of the junk above
* `void main' isn't needed for the skeleton, but is likely to be for what
* you'll do with it.
*
* If you compile this, it will turn into an expensive GIF copying routine;
* stdin to stdout with no changes and minimal validation. Well, it's a
* decent test of the low-level routines, anyway.
*
* Note: due to the vicissitudes of Lempel-Ziv compression, the output of this
* copier may not be bitwise identical to its input. This can happen if you
* copy an image from a much more (or much *less*) memory-limited system; your
* compression may use more (or fewer) bits. The uncompressed rasters should,
* however, be identical (you can check this with icon2gif -d).
*/
#ifdef __MSDOS__
#include <dos.h>
#include <alloc.h>
#include <stdlib.h>
#include <graphics.h>
#include <io.h>
#endif /* __MSDOS__ */
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include "gagetarg.h"
#include "gif_lib.h"
#define PROGRAM_NAME "giffiltr"
#ifdef __MSDOS__
extern unsigned int
_stklen = 16384; /* Increase default stack size. */
#endif /* __MSDOS__ */
/******************************************************************************
* Close both input and output file (if open), and exit. *
******************************************************************************/
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut)
{
PrintGifError();
if (GifFileIn != NULL) DGifCloseFile(GifFileIn);
if (GifFileOut != NULL) EGifCloseFile(GifFileOut);
exit(1);
}
/******************************************************************************
* Main sequence *
******************************************************************************/
void main(int argc, char **argv)
{
GifFileType *GifFileIn = NULL, *GifFileOut = NULL;
GifRecordType RecordType;
int CodeSize, ExtCode;
GifByteType *CodeBlock, *Extension;
/*
* Command-line processing goes here.
*/
/* Use the stdin as input (note this also read screen descriptor in: */
if ((GifFileIn = DGifOpenFileHandle(0)) == NULL)
QuitGifError(GifFileIn, GifFileOut);
/* Use the stdout as output: */
if ((GifFileOut = EGifOpenFileHandle(1)) == NULL)
QuitGifError(GifFileIn, GifFileOut);
/* 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:
/* Copy the extension header */
if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
if (EGifPutExtensionHeader(GifFileOut, ExtCode) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
/* Copy the extension data blocks */
while (Extension != NULL) {
if (EGifPutExtensionBlock(GifFileOut, Extension[0],
Extension+1) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
if (DGifGetExtensionNext(GifFileIn, &Extension) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
}
/* Close the extension with a 0 length data block */
if (EGifPutExtensionBlock(GifFileOut, 0, NULL) == 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) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
if (EGifCloseFile(GifFileOut) == GIF_ERROR)
QuitGifError(GifFileIn, GifFileOut);
exit(0);
}
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