anchor.diff:  
   handle_info(update, #state{universaltime=Prev, rfc1123=B1, tref=TRef}) ->
   	T = erlang:universaltime(),
  -	B2 = update_rfc1123(Prev, T, B1),
  +	B2 = update_rfc1123(B1, Prev, T),
   	ets:insert(?TABLE, {rfc1123, B2}),
   	{noreply, #state{universaltime=T, rfc1123=B2, tref=TRef}};
   
  
positive.code: 		{<<"Sun, 01 Jan 2012 00:00:00 GMT">>, {{2011, 5, 31}, {23, 59, 59}},
  			{{2012, 1,  1}, { 0,  0,  0}}, <<"Sat, 31 Dec 2011 23:59:59 GMT">>}
  	],
  	[{R, fun() -> R = update_rfc1123(P, N, B) end} || {R, P, N, B} <- Tests].
  
  pad_int_test_() ->
  	Tests = [
  
negative.code: 
  %% Internal.
  
  -spec update_rfc1123(binary(), undefined | datetime(), datetime()) -> binary().
  update_rfc1123(Bin, Now, Now) ->
  	Bin;
  update_rfc1123(<< Keep:23/binary, _/bits >>,
  		{Date, {H, M, _}}, {Date, {H, M, S}}) ->
  	<< Keep/binary, (pad_int(S))/binary, " GMT" >>;
  update_rfc1123(<< Keep:20/binary, _/bits >>,
  		{Date, {H, _, _}}, {Date, {H, M, S}}) ->
  	<< Keep/binary, (pad_int(M))/binary, $:, (pad_int(S))/binary, " GMT" >>;
  update_rfc1123(<< Keep:17/binary, _/bits >>, {Date, _}, {Date, {H, M, S}}) ->
  	<< Keep/binary, (pad_int(H))/binary, $:, (pad_int(M))/binary,
  		$:, (pad_int(S))/binary, " GMT" >>;
  update_rfc1123(<< _:7/binary, Keep:10/binary, _/bits >>,
  		{{Y, Mo, _}, _}, {Date = {Y, Mo, D}, {H, M, S}}) ->
  	Wday = calendar:day_of_the_week(Date),
  	<< (weekday(Wday))/binary, ", ", (pad_int(D))/binary, Keep/binary,
  		(pad_int(H))/binary, $:, (pad_int(M))/binary,
  		$:, (pad_int(S))/binary, " GMT" >>;
  update_rfc1123(<< _:11/binary, Keep:6/binary, _/bits >>,
  		{{Y, _, _}, _}, {Date = {Y, Mo, D}, {H, M, S}}) ->
  	Wday = calendar:day_of_the_week(Date),
  	<< (weekday(Wday))/binary, ", ", (pad_int(D))/binary, " ",
  		(month(Mo))/binary, Keep/binary,
  		(pad_int(H))/binary, $:, (pad_int(M))/binary,
  		$:, (pad_int(S))/binary, " GMT" >>;
  update_rfc1123(_, _, {Date = {Y, Mo, D}, {H, M, S}}) ->
  	Wday = calendar:day_of_the_week(Date),
  	<< (weekday(Wday))/binary, ", ", (pad_int(D))/binary, " ",
  		(month(Mo))/binary, " ", (list_to_binary(integer_to_list(Y)))/binary,
  