if(length $string>256){
   # remove trailing spaces
   while (length $string>256 && $string=~m/(?:^\s)*\s+$/){
      $string =~ s/(.*)\s$/$1/;
   }

   # remove beginning spaces
   while (length $string>256 && $string=~m/^\s+[^\s]/){
      $string =~ s/^\s(.*)/$1/;
   }

   # anything else
   if (length $string >256){
      $string = substr($string,0,256);
   }
}