anchor.diff:  -spec ceil(N :: number()) -> integer().
   %% ====================================================================
   ceil(N) when trunc(N) == N -> N;
  -ceil(N) -> trunc(N+1).
  +ceil(N) -> trunc(N + 1).
   
   %% parse_byte_range/1
   %% ====================================================================
  
positive.code: 
              % reply with stream and adequate status
              {ok, Req3} = case RawRange of
                               undefined -> cowboy_req:reply(?ok, [], {StreamSize,StreamFun}, Req2);
                               _ -> cowboy_req:reply(?ok_partial_content, [], {StreamSize,StreamFun}, Req2)
                           end,
              {halt, Req3, State}
      end.
  
negative.code:             end,
      case Range of
          [invalid] -> [invalid];
          {Begin, End} when Begin > End -> [invalid];
          {Begin_, _End} when Begin_ > Size -> parse_byte_range(State, Rest); % range is unsatisfiable and we ignore it
          ValidRange -> [ValidRange | parse_byte_range(State, Rest)]
      end.
  
  