anchor.diff:  horse_parse_sec_websocket_version_req_255() ->
   	horse:repeat(200000,
   		parse_sec_websocket_version_req(<<"255">>)
  +	).
  +-endif.
  +
  +%% @doc Parse the Sec-WebSocket-Version response header.
  +
  +-spec parse_sec_websocket_version_resp(binary()) -> [websocket_version()].
  +parse_sec_websocket_version_resp(SecWebSocketVersion) ->
  +	nonempty(ws_version_list(SecWebSocketVersion, [])).
  +
  +ws_version_list(<<>>, Acc) -> lists:reverse(Acc);
  +ws_version_list(<< $\s, R/bits >>, Acc) -> ws_version_list(R, Acc);
  +ws_version_list(<< $\t, R/bits >>, Acc) -> ws_version_list(R, Acc);
  +ws_version_list(<< $,, R/bits >>, Acc) -> ws_version_list(R, Acc);
  +ws_version_list(<< C, R/bits >>, Acc) when ?IS_DIGIT(C) -> ws_version(R, Acc, C - $0).
  +
  +ws_version(<<>>, Acc, V) -> lists:reverse([V|Acc]);
  +ws_version(<< $\s, R/bits >>, Acc, V) -> ws_version_list_sep(R, [V|Acc]);
  +ws_version(<< $\t, R/bits >>, Acc, V) -> ws_version_list_sep(R, [V|Acc]);
  +ws_version(<< $,, R/bits >>, Acc, V) -> ws_version_list(R, [V|Acc]);
  +ws_version(<< C, R/bits >>, Acc, V) when ?IS_DIGIT(C) -> ws_version(R, Acc, V * 10 + C - $0).
  +
  +ws_version_list_sep(<<>>, Acc) -> lists:reverse(Acc);
  +ws_version_list_sep(<< $\s, R/bits >>, Acc) -> ws_version_list_sep(R, Acc);
  +ws_version_list_sep(<< $\t, R/bits >>, Acc) -> ws_version_list_sep(R, Acc);
  +ws_version_list_sep(<< $,, R/bits >>, Acc) -> ws_version_list(R, Acc).
  +
  +-ifdef(TEST).
  +sec_websocket_version_resp() ->
  +	?LET(L,
  +		non_empty(list({ows(), ows(), int(0, 255)})),
  +		begin
  +			<< _, SecWebSocketVersion/binary >> = iolist_to_binary(
  +				[[OWS1, $,, OWS2, integer_to_binary(V)] || {OWS1, OWS2, V} <- L]),
  +			{[V || {_, _, V} <- L], SecWebSocketVersion}
  +		end).
  +
  +prop_parse_sec_websocket_version_resp() ->
  +	?FORALL({L, SecWebSocketVersion},
  +		sec_websocket_version_resp(),
  +		L =:= parse_sec_websocket_version_resp(SecWebSocketVersion)).
  +
  +parse_sec_websocket_version_resp_test_() ->
  +	Tests = [
  +		{<<"13, 8, 7">>, [13, 8, 7]}
  +	],
  +	[{V, fun() -> R = parse_sec_websocket_version_resp(V) end} || {V, R} <- Tests].
  +
  +parse_sec_websocket_version_resp_error_test_() ->
  +	Tests = [
  +		<<>>
  +	],
  +	[{V, fun() -> {'EXIT', _} = (catch parse_sec_websocket_version_resp(V)) end}
  +		|| V <- Tests].
  +-endif.
  +
  +-ifdef(PERF).
  +horse_parse_sec_websocket_version_resp() ->
  +	horse:repeat(200000,
  +		parse_sec_websocket_version_resp(<<"13, 8, 7">>)
   	).
   -endif.
   
  
positive.code: 
  %% @doc Parse the Sec-WebSocket-Version request header.
  
  -spec parse_sec_websocket_version_req(binary()) -> 0..255.
  parse_sec_websocket_version_req(SecWebSocketVersion) when byte_size(SecWebSocketVersion) < 4 ->
  	Version = binary_to_integer(SecWebSocketVersion),
  	true = Version >= 0 andalso Version =< 255,
  
negative.code: 
  -type qvalue() :: 0..1000.
  -export_type([qvalue/0]).
  
  -type websocket_version() :: 0..255.
  -export_type([websocket_version/0]).
  
  -include("cow_inline.hrl").
  
  