static unsigned postProcessScanlines(unsigned char* out, unsigned char* in,
                                     unsigned w, unsigned h, const LodePNGInfo* info_png)
{
  /*
  This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype.
  Steps:
  *) if no Adam7: 1) unfilter 2) remove padding bits (= posible extra bits per scanline if bpp < 8)
  *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace
  NOTE: the in buffer will be overwritten with intermediate data!
  */
  unsigned bpp = lodepng_get_bpp(&info_png->color);
  if(bpp == 0) return 31; /*error: invalid colortype*/

  if(info_png->interlace_method == 0)
  {
    if(bpp < 8 && w * bpp != ((w * bpp + 7) / 8) * 8)
    {
      CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp));
      removePaddingBits(out, in, w * bpp, ((w * bpp + 7) / 8) * 8, h);
    }
    /*we can immediatly filter into the out buffer, no other steps needed*/
    else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp));
  }
  else /*interlace_method is 1 (Adam7)*/
  {
    unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
    unsigned i;

    Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);

    for(i = 0; i < 7; i++)
    {
      CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp));
      /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline,
      move bytes instead of bits or move not at all*/
      if(bpp < 8)
      {
        /*remove padding bits in scanlines; after this there still may be padding
        bits between the different reduced images: each reduced image still starts nicely at a byte*/
        removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp,
                          ((passw[i] * bpp + 7) / 8) * 8, passh[i]);
      }
    }

    Adam7_deinterlace(out, in, w, h, bpp);
  }

  return 0;
}
Unknown