void GfxImageColorMap::getGrayLine(Guchar *in, Guchar *out, int length) {
  int i, j;
  Guchar *inp, *tmp_line;

   switch (colorSpace->getMode()) {
   case csIndexed:
   case csSeparation:
    tmp_line = (Guchar *) gmallocn (length, nComps2);
     for (i = 0; i < length; i++) {
       for (j = 0; j < nComps2; j++) {
 	tmp_line[i * nComps2 + j] = byte_lookup[in[i] * nComps2 + j];
      }
    }
    colorSpace2->getGrayLine(tmp_line, out, length);
    gfree (tmp_line);
    break;

  default:
    inp = in;
    for (j = 0; j < length; j++)
      for (i = 0; i < nComps; i++) {
	*inp = byte_lookup[*inp * nComps + i];
	inp++;
      }
    colorSpace->getGrayLine(in, out, length);
    break;
  }

}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.