anchor.diff:  -endif.
   
   -record(mstore, {
  -          size :: pos_integer(),
  -          max_files = 2 :: non_neg_integer(),
  -          files = [] :: [{non_neg_integer(), mfile:mfile()}],
  -          dir :: string(),
  +          size              :: pos_integer(),
  +          max_files = 2     :: non_neg_integer(),
  +          files = []        :: [{non_neg_integer(), mfile:mfile()}],
  +          dir               :: string(),
             metrics = delayed :: btrie:btrie() | delayed
            }).
   
  
positive.code:     do_fold_idx(IO, Chunk,
                  fun({entry, M}, Acc) ->
                          btrie:store(M, Acc)
                  end, btrie:new(), R);    
  maybe_read_index(IO, _Chunk, _R, false) ->
      file:close(IO),
      delayed.
  
negative.code:         mstore(),
          binary(),
          non_neg_integer()) ->
                      {'error',atom()} |
                      {ok, bitmap:bitmap()}.
  
  bitmap(#mstore{size=S, files=FS, dir=Dir},
         Metric, Time) when
        is_binary(Metric),
        is_integer(Time), Time >= 0 ->
      R = do_get_bitmap(S, FS, Dir, Metric, Time),
  