anchor.diff:  
   -record(pieceset, {
       size :: pos_integer(),
  -    elements :: pos_integer()}).
  +    elements :: binary()}).
   
   %% @doc
   %% Create an empty set of piece indexes. The set of pieces
   %% is limited to contain pieces indexes from 0 to Size-1.
   %% @end
   new(Size) ->
  -    #pieceset{size=Size, elements=0}.
  +    PaddingLen = paddinglen(Size),
  +    Elements = <<0:Size, 0:PaddingLen>>,
  +    #pieceset{size=Size, elements=Elements}.
   
   %% @doc
   %% Create a piece set based on a bitfield. The bitfield is
  
positive.code:         false ->
              error(badarg);
          true ->
              (Elements band piecemask(PieceIndex, Size)) > 0
      end.
  
  %% @doc
  
negative.code:         false ->
              error(badarg);
          true ->
              PaddingLen = paddinglen(PieceIndex + 1),
              <<Low:PieceIndex, _:1, Padding:PaddingLen, High/binary>> = Elements,
              Updated = <<Low:PieceIndex, 1:1, Padding:PaddingLen, High/binary>>,
              Pieceset#pieceset{elements=Updated}
      end.
  
  %% @doc
  