  gray_convert_glyph( RAS_ARG )
  {
    TBand            bands[40];
    TBand* volatile  band;
    int volatile     n, num_bands;
    TPos volatile    min, max, max_y;
    FT_BBox*         clip;


    /* Set up state in the raster object */
    gray_compute_cbox( RAS_VAR );

    /* clip to target bitmap, exit if nothing to do */
    clip = &ras.clip_box;

    if ( ras.max_ex <= clip->xMin || ras.min_ex >= clip->xMax ||
         ras.max_ey <= clip->yMin || ras.min_ey >= clip->yMax )
      return 0;

    if ( ras.min_ex < clip->xMin ) ras.min_ex = clip->xMin;
    if ( ras.min_ey < clip->yMin ) ras.min_ey = clip->yMin;

    if ( ras.max_ex > clip->xMax ) ras.max_ex = clip->xMax;
    if ( ras.max_ey > clip->yMax ) ras.max_ey = clip->yMax;

    ras.count_ex = ras.max_ex - ras.min_ex;
    ras.count_ey = ras.max_ey - ras.min_ey;

    /* simple heuristic used to speed up the bezier decomposition -- see */
    /* the code in gray_render_conic() and gray_render_cubic() for more  */
    /* details                                                           */
    ras.conic_level = 32;
    ras.cubic_level = 16;

    {
      int  level = 0;


      if ( ras.count_ex > 24 || ras.count_ey > 24 )
        level++;
      if ( ras.count_ex > 120 || ras.count_ey > 120 )
        level++;

      ras.conic_level <<= level;
      ras.cubic_level <<= level;
    }

    /* set up vertical bands */
    num_bands = (int)( ( ras.max_ey - ras.min_ey ) / ras.band_size );
    if ( num_bands == 0 )
      num_bands = 1;
    if ( num_bands >= 39 )
      num_bands = 39;

    ras.band_shoot = 0;

    min   = ras.min_ey;
    max_y = ras.max_ey;

    for ( n = 0; n < num_bands; n++, min = max )
    {
      max = min + ras.band_size;
      if ( n == num_bands - 1 || max > max_y )
        max = max_y;

      bands[0].min = min;
      bands[0].max = max;
      band         = bands;

      while ( band >= bands )
      {
        TPos  bottom, top, middle;
        int   error;

        {
          PCell  cells_max;
          int    yindex;
          long   cell_start, cell_end, cell_mod;


          ras.ycells = (PCell*)ras.buffer;
          ras.ycount = band->max - band->min;

          cell_start = sizeof ( PCell ) * ras.ycount;
          cell_mod   = cell_start % sizeof ( TCell );
          if ( cell_mod > 0 )
            cell_start += sizeof ( TCell ) - cell_mod;

          cell_end  = ras.buffer_size;
          cell_end -= cell_end % sizeof( TCell );

          cells_max = (PCell)( (char*)ras.buffer + cell_end );
          ras.cells = (PCell)( (char*)ras.buffer + cell_start );
          if ( ras.cells >= cells_max )
            goto ReduceBands;

          ras.max_cells = cells_max - ras.cells;
          if ( ras.max_cells < 2 )
            goto ReduceBands;

          for ( yindex = 0; yindex < ras.ycount; yindex++ )
            ras.ycells[yindex] = NULL;
        }

        ras.num_cells = 0;
        ras.invalid   = 1;
        ras.min_ey    = band->min;
        ras.max_ey    = band->max;
        ras.count_ey  = band->max - band->min;

        error = gray_convert_glyph_inner( RAS_VAR );

        if ( !error )
        {
          gray_sweep( RAS_VAR_ &ras.target );
          band--;
          continue;
        }
        else if ( error != ErrRaster_Memory_Overflow )
          return 1;

      ReduceBands:
        /* render pool overflow; we will reduce the render band by half */
        bottom = band->min;
        top    = band->max;
        middle = bottom + ( ( top - bottom ) >> 1 );

        /* This is too complex for a single scanline; there must */
        /* be some problems.                                     */
        if ( middle == bottom )
        {
#ifdef FT_DEBUG_LEVEL_TRACE
          FT_TRACE7(( "gray_convert_glyph: rotten glyph\n" ));
#endif
          return 1;
        }

        if ( bottom-top >= ras.band_size )
          ras.band_shoot++;

        band[1].min = bottom;
        band[1].max = middle;
        band[0].min = middle;
        band[0].max = top;
        band++;
      }
    }

    if ( ras.band_shoot > 8 && ras.band_size > 16 )
      ras.band_size = ras.band_size / 2;

    return 0;
  }

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