/*********************************************************/
/*   program 24: hit-and-miss LUT erosion and dilation   */
/*********************************************************/

#define  XSIZE  640
#define  YSIZE  480

main()
  {
  unsigned char *ip;
  unsigned char *op;
  unsigned char *i1,*i2,*i3;
  unsigned char *o1,*o2,*o3;
  unsigned char lut[512];
  long  int  x,y;
  long  int  l;

  /* generate erode lut: */
  for (x = 0; x < 512; x++) lut[x] = 0x00;
  lut[0x1ff] = 0xff;

  /* generate dilate lut:
  for (x = 0; x < 512; x++) lut[x] = 0xff;
  lut[0x000] = 0x00;
  */

  /* allocate input and output memory buffers */
  ip = (unsigned char *) malloc (XSIZE*YSIZE);
  op = (unsigned char *) malloc (XSIZE*YSIZE);

  /* read the input image (one plane image) */
  read_image("input",ip);

  /* initialize pointers into buffers */
  i2 = ip;
  i3 = ip + XSIZE;
  o2 = op;
  o3 = op + XSIZE;

  /* process all lines of image */
  for (y = 1; y < (YSIZE-1); y++)
    {
    /* set pointers for this line */
    i1 = i2;
    i2 = i3;
    i3 = i3 + XSIZE;
    o1 = o2;
    o2 = o3;
    o3 = o3 + XSIZE;

    /* process all pixels in line */
    for (x = 1; x < (XSIZE-1); x++)
      {
      /* generate index into lut from binary pixels */
      l = ((*(i2+x+0) & 0x01) << 8) +
          ((*(i2+x+1) & 0x01) << 7) +
          ((*(i1+x+1) & 0x01) << 6) +
          ((*(i1+x+0) & 0x01) << 5) +
          ((*(i1+x-1) & 0x01) << 4) +
          ((*(i2+x-1) & 0x01) << 3) +
          ((*(i3+x-1) & 0x01) << 2) +
          ((*(i3+x+0) & 0x01) << 1) +
           (*(i3+x+1) & 0x01);

      /* perform look-up table operation */
      *(o2+x) = lut[l];
      }
    }

  /* write the output image */
  write_image("output",op);

  /* free memory buffers */
  free(ip);
  free(op);
}