anchor.diff:          PrevCount = array:get(Index, Acc),
           array:set(Index, PrevCount + 1, Acc)
       end, Numpeers, Piecelist).
  +
   
   -spec send_updates(pieceset() | pos_integer(), [#subscription{}], array()) -> ok.
   send_updates(Index, Subscriptions, Numpeers) when is_integer(Index) ->
  
positive.code:         IsMatching(SubPieceset)],
      [send_update(Sub, Numpeers) || Sub <- Matching],
      ok.
  
  -spec send_update(#subscription{}, array()) -> ok.
  send_update(Subscription, Numpeers) ->
  
negative.code: code_change(_, State, _) ->
      {ok, State}.
  
  
  -spec sorted_piecelist(pieceset(), array()) -> [pos_integer()].
  sorted_piecelist(Pieceset, Numpeers) ->
      Piecelist = etorrent_pieceset:to_list(Pieceset),
      lists:sort(fun(A, B) ->
          array:get(A, Numpeers) =< array:get(B, Numpeers)
      end, Piecelist).
  
  
  -spec decrement(pieceset(), array()) -> array().
  decrement(Pieceset, Numpeers) ->
  