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gif2rle.c

/*****************************************************************************
*   "Gif-Lib" - Yet another gif library.                         *
*                                                          *
* Written by:  Gershon Elber                    Ver 0.1, Jul. 1989   *
******************************************************************************
* Program to convert GIF file RLE format (utah raster toolkit).              *
* Options:                                                 *
* -q : quiet printing mode.                                      *
* -a : add alpha channel with full coverage.                           *
* -h : on-line help.                                             *
******************************************************************************
* History:                                                 *
* 5 Jan 90 - Version 1.0 by Gershon Elber.                             *
*****************************************************************************/

#ifdef __MSDOS__
#include <graphics.h>
#include <stdlib.h>
#include <alloc.h>
#include <io.h>
#include <dos.h>
#include <bios.h>
#endif /* __MSDOS__ */

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <fcntl.h>
#include "gif_lib.h"
#include "getarg.h"

#include "rle.h"                 /* The rle tool kit header files. */

#define PROGRAM_NAME    "Gif2Rle"

#ifdef __MSDOS__
extern unsigned int
    _stklen = 16384;                     /* Increase default stack size. */
#endif /* __MSDOS__ */

#ifdef SYSV
static char *VersionStr =
        "Gif toolkit module,\t\tGershon Elber\n\
      (C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr = "Gif2Rle q%- a%- h%- GifFile!*s";
#else
static char
    *VersionStr =
      PROGRAM_NAME
      GIF_LIB_VERSION
      "     Gershon Elber,    "
      __DATE__ ",   " __TIME__ "\n"
      "(C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr =
      PROGRAM_NAME
      " q%- a%- h%- GifFile!*s";
#endif /* SYSV */

/* Make some variables global, so we could access them faster: */
static int
    ImageNum = 0,
    BackGround = 0,
    AlphaFlag = FALSE,
    HelpFlag = FALSE,
    ColorMapSize = 0,
    InterlacedOffset[] = { 0, 4, 2, 1 }, /* The way Interlaced image should. */
    InterlacedJumps[] = { 8, 8, 4, 2 };    /* be read - offsets and jumps... */
static GifColorType
    *ColorMap;

static void DumpScreen2Rle(GifRowType *ScreenBuffer,
                              int ScreenWidth, int ScreenHeight);

/******************************************************************************
* Interpret the command line and scan the given GIF file.               *
******************************************************************************/
void main(int argc, char **argv)
{
    int     i, j, Error, NumFiles, Size, Row, Col, Width, Height, ExtCode, Count;
    GifRecordType RecordType;
    GifByteType *Extension;
    char **FileName = NULL;
    GifRowType *ScreenBuffer;
    GifFileType *GifFile;

    if ((Error = GAGetArgs(argc, argv, CtrlStr, &GifQuietPrint,
            &AlphaFlag, &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(1);
    }

    if (HelpFlag) {
      fprintf(stderr, VersionStr);
      GAPrintHowTo(CtrlStr);
      exit(0);
    }
    
    if (NumFiles == 1) {
      if ((GifFile = DGifOpenFileName(*FileName)) == NULL) {
          PrintGifError();
          exit(-1);
      }
    }
    else {
      /* Use the stdin instead: */

#ifdef __MSDOS__
      setmode(0, O_BINARY);
#endif /* __MSDOS__ */
      if ((GifFile = DGifOpenFileHandle(0)) == NULL) {
          PrintGifError();
          exit(-1);
      }
    }

    /* Allocate the screen as vector of column of rows. We cannt allocate    */
    /* the all screen at once, as this broken minded CPU can allocate up to  */
    /* 64k at a time and our image can be bigger than that:            */
    /* Note this screen is device independent - its the screen as defined by */
    /* the GIF file parameters itself.                                 */
    if ((ScreenBuffer = (GifRowType *)
      malloc(GifFile->SHeight * sizeof(GifRowType *))) == NULL)
          GIF_EXIT("Failed to allocate memory required, aborted.");

    Size = GifFile->SWidth * sizeof(GifPixelType);/* Size in bytes one row.*/
    if ((ScreenBuffer[0] = (GifRowType) malloc(Size)) == NULL) /* First row. */
      GIF_EXIT("Failed to allocate memory required, aborted.");

    for (i = 0; i < GifFile->SWidth; i++)  /* Set its color to BackGround. */
      ScreenBuffer[0][i] = GifFile->SBackGroundColor;
    for (i = 1; i < GifFile->SHeight; i++) {
      /* Allocate the other rows, and set their color to background too: */
      if ((ScreenBuffer[i] = (GifRowType) malloc(Size)) == NULL)
          GIF_EXIT("Failed to allocate memory required, aborted.");

      memcpy(ScreenBuffer[i], ScreenBuffer[0], Size);
    }

    /* Scan the content of the GIF file and load the image(s) in: */
    do {
      if (DGifGetRecordType(GifFile, &RecordType) == GIF_ERROR) {
          PrintGifError();
          exit(-1);
      }
      switch (RecordType) {
          case IMAGE_DESC_RECORD_TYPE:
            if (DGifGetImageDesc(GifFile) == GIF_ERROR) {
                PrintGifError();
                exit(-1);
            }
            Row = GifFile->Image.Top; /* Image Position relative to Screen. */
            Col = GifFile->Image.Left;
            Width = GifFile->Image.Width;
            Height = GifFile->Image.Height;
            GifQprintf("\n%s: Image %d at (%d, %d) [%dx%d]:     ",
                PROGRAM_NAME, ++ImageNum, Col, Row, Width, Height);
            if (GifFile->Image.Left + GifFile->Image.Width > GifFile->SWidth ||
               GifFile->Image.Top + GifFile->Image.Height > GifFile->SHeight) {
                fprintf(stderr, "Image %d is not confined to screen dimension, aborted.\n");
                exit(-2);
            }
            if (GifFile->Image.Interlace) {
                /* Need to perform 4 passes on the images: */
                for (Count = i = 0; i < 4; i++)
                  for (j = Row + InterlacedOffset[i]; j < Row + Height;
                                     j += InterlacedJumps[i]) {
                      GifQprintf("\b\b\b\b%-4d", Count++);
                      if (DGifGetLine(GifFile, &ScreenBuffer[j][Col],
                        Width) == GIF_ERROR) {
                        PrintGifError();
                        exit(-1);
                      }
                  }
            }
            else {
                for (i = 0; i < Height; i++) {
                  GifQprintf("\b\b\b\b%-4d", i);
                  if (DGifGetLine(GifFile, &ScreenBuffer[Row++][Col],
                        Width) == GIF_ERROR) {
                      PrintGifError();
                      exit(-1);
                  }
                }
            }
            break;
          case EXTENSION_RECORD_TYPE:
            /* Skip any extension blocks in file: */
            if (DGifGetExtension(GifFile, &ExtCode, &Extension) == GIF_ERROR) {
                PrintGifError();
                exit(-1);
            }
            while (Extension != NULL) {
                if (DGifGetExtensionNext(GifFile, &Extension) == GIF_ERROR) {
                  PrintGifError();
                  exit(-1);
                }
            }
            break;
          case TERMINATE_RECORD_TYPE:
            break;
          default:                /* Should be traps by DGifGetRecordType. */
            break;
      }
    }
    while (RecordType != TERMINATE_RECORD_TYPE);

    /* Lets display it - set the global variables required and do it: */
    BackGround = GifFile->SBackGroundColor;
    ColorMap = (GifFile->Image.ColorMap ? GifFile->Image.ColorMap :
                               GifFile->SColorMap);
    ColorMapSize = 1 << (GifFile->Image.ColorMap ? GifFile->Image.BitsPerPixel :
                                        GifFile->SBitsPerPixel);
    DumpScreen2Rle(ScreenBuffer, GifFile->SWidth, GifFile->SHeight);

    if (DGifCloseFile(GifFile) == GIF_ERROR) {
      PrintGifError();
      exit(-1);
    }
}

/******************************************************************************
* The real dumping routine.                                       *
******************************************************************************/
static void DumpScreen2Rle(GifRowType *ScreenBuffer,
                              int ScreenWidth, int ScreenHeight)
{
    int i, j;
    char Comment[80];
    rle_pixel *rows[4];
    GifRowType GifRow;
    static GifColorType
      *ColorMapEntry;

    if (AlphaFlag) RLE_SET_BIT(rle_dflt_hdr, RLE_ALPHA);
    rle_dflt_hdr.alpha = AlphaFlag != 0;
    rle_dflt_hdr.rle_file = stdout;
    rle_dflt_hdr.xmin = 0;
    rle_dflt_hdr.ymin = 0;
    rle_dflt_hdr.xmax = ScreenWidth - 1;
    rle_dflt_hdr.ymax = ScreenHeight - 1;
    sprintf(Comment, "origin=GIF format, %d colors.", ColorMapSize);
    rle_putcom(Comment, &rle_dflt_hdr);
    rle_put_setup(&rle_dflt_hdr);

    for (i = 0; i < 4; i++)
      if ((rows[i] = (rle_pixel *) malloc(sizeof(rle_pixel) * ScreenWidth))
                                                     == NULL)
          GIF_EXIT("Failed to allocated memory required, aborted.");

    if (AlphaFlag) {
      /* Initial the alpha channel to full coverage: */
      for (i = 0; i < ScreenWidth; i++) rows[0][i] = 255;
    }

    for (i = 0; i < ScreenHeight; i++) {
      /* Flip the image vertically as rle files start at the bollom... */
      GifRow = ScreenBuffer[ScreenHeight - i - 1];
      GifQprintf("\b\b\b\b%-4d", ScreenHeight - i);
      for (j = 0; j < ScreenWidth; j++) {
          ColorMapEntry = &ColorMap[GifRow[j]];
          rows[1][j] = ColorMapEntry->Red;
          rows[2][j] = ColorMapEntry->Green;
          rows[3][j] = ColorMapEntry->Blue;
      }
      rle_putrow( &rows[1], ScreenWidth, &rle_dflt_hdr );
    }

    rle_puteof( &rle_dflt_hdr );
}

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