  cff_builder_close_contour( CFF_Builder*  builder )
  {
    FT_Outline*  outline = builder->current;
    FT_Int       first;


    if ( !outline )
      return;

    first = outline->n_contours <= 1
            ? 0 : outline->contours[outline->n_contours - 2] + 1;

    /* We must not include the last point in the path if it */
    /* is located on the first point.                       */
    if ( outline->n_points > 1 )
    {
      FT_Vector*  p1      = outline->points + first;
      FT_Vector*  p2      = outline->points + outline->n_points - 1;
      FT_Byte*    control = (FT_Byte*)outline->tags + outline->n_points - 1;


      /* `delete' last point only if it coincides with the first    */
      /* point and if it is not a control point (which can happen). */
      if ( p1->x == p2->x && p1->y == p2->y )
        if ( *control == FT_CURVE_TAG_ON )
          outline->n_points--;
    }

    if ( outline->n_contours > 0 )
    {
      /* Don't add contours only consisting of one point, i.e., */
      /* check whether begin point and last point are the same. */
      if ( first == outline->n_points - 1 )
      {
        outline->n_contours--;
        outline->n_points--;
      }
      else
        outline->contours[outline->n_contours - 1] =
          (short)( outline->n_points - 1 );
    }
  }

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