Tagging NIF parsing results with {ok, _}

c_src/exml.c

@@ -141,7 +141,9 @@ ERL_NIF_TERM parse(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
                                    enif_make_string(env, errstring, ERL_NIF_LATIN1));
         }
 
-    return parser_data->result;
+    return enif_make_tuple(env, 2,
+                           enif_make_atom(env, "ok"),
+                           parser_data->result);
 };
 
 static int load(ErlNifEnv* env, void **priv, ERL_NIF_TERM info)

src/exml.erl

@@ -23,9 +23,14 @@ new_parser() ->
 free_parser(_Parser) ->
     throw({?MODULE, nif_not_loaded}).
 
--spec parse(term(), binary(), boolean()) -> list().
+-spec parse(term(), binary(), boolean()) -> {ok, list()} | {error, string()}.
 parse(Parser, Data, Final) ->
-    lists:reverse(parse_nif(Parser, Data, bool(Final))).
+    case parse_nif(Parser, Data, bool(Final)) of
+        {ok, Res} ->
+            {ok, lists:reverse(Res)};
+        Error ->
+            Error
+    end.
 
 -spec parse_nif(term(), binary(), integer()) -> list().
 parse_nif(_Parser, _Data, _Final) ->

test/benchmarks.erl

@@ -0,0 +1,63 @@
+%%%-------------------------------------------------------------------
+%%% @author Michal Ptaszek <michal.ptaszek@erlang-solutions.com>
+%%% @copyright (C) 2011, Erlang Solutions Ltd.
+%%% @doc A set of benchmarks comparing expat_sax_parser, erlsom and exml.
+%%%
+%%% @end
+%%% Created : 15 Jul 2011 by Michal Ptaszek <michal.ptaszek@erlang-solutions.com>
+%%%-------------------------------------------------------------------
+-module(benchmarks).
+
+-export([run/2,
+         run_exml/3,
+         run_erlsom/3,
+         run_xmerl/3]).
+
+run(Path, N) ->
+    application:start(exml),
+    [apply(?MODULE, F, [Path, N, []]) || F <- [run_exml, run_erlsom, run_xmerl]],
+    application:stop(exml).
+
+run_exml(_, 0, Acc) ->
+    Avg = avg(Acc),
+    io:format("Total: ~w~n"
+              "Avg: ~w~n"
+              "Std dev.: ~w~n",
+              [total(Acc), Avg, std_dev(Acc, Avg)]);
+run_exml(Path, N, Acc) ->
+    {ok, Fd} = file:open(Path, [read, binary, read_ahead]),
+    T = now(),
+
+    {ok, Parser} = exml:new_parser(),
+    run_exml(Fd, Parser),
+    exml:free_parser(Parser),
+
+    Diff = timer:now_diff(now(), T),
+    run_exml(Path, N-1, [Diff | Acc]).
+
+run_exml(Fd, Parser) ->
+    case file:read_line(Fd) of
+        eof ->
+            ok;
+        {ok, Data} ->
+            exml:parse(Parser, Data, true),
+            run_exml(Fd, Parser)
+    end.
+
+total(Times) ->
+    lists:sum(Times).
+
+avg(Times) ->
+    total(Times)/length(Times).
+
+std_dev(Times, Avg) ->
+    Sums = lists:foldl(
+             fun(V, Acc) -> D = V - Avg, Acc + (D * D) end,
+             0, Times),
+    math:sqrt(Sums / (length(Times) - 1)).
+
+run_xmerl(_, _, _) ->
+    ok.
+
+run_erlsom(_, _, _) ->
+    ok.

test/exml_tests.erl

@@ -23,33 +23,33 @@ application_test() ->
 basic_parse_test() ->
     {ok, Parser} = exml:new_parser(),
 
-    ?assertEqual([{xml_element_start, <<"test">>, []},
-                  {xml_element_end, <<"test">>}],
+    ?assertEqual({ok, [{xml_element_start, <<"test">>, []},
+                       {xml_element_end, <<"test">>}]},
                  exml:parse(Parser, <<"<test/>">>, true)),
     ?assertEqual(ok, exml:free_parser(Parser)).
 
 attrs_parsing_test() ->
     {ok, Parser} = exml:new_parser(),
 
-    ?assertEqual([{xml_element_start, <<"test">>, [{<<"attr">>, <<"val">>},
-                                                   {<<"second_attr">>, <<"val2">>}]},
-                  {xml_element_end, <<"test">>}],
+    ?assertEqual({ok, [{xml_element_start, <<"test">>, [{<<"attr">>, <<"val">>},
+                                                        {<<"second_attr">>, <<"val2">>}]},
+                       {xml_element_end, <<"test">>}]},
                  exml:parse(Parser, <<"<test attr='val' second_attr='val2'/>">>, true)),
     ?assertEqual(ok, exml:free_parser(Parser)).
 
 open_tag_test() ->
     {ok, Parser} = exml:new_parser(),
 
-    ?assertEqual([{xml_element_start, <<"test">>, []}],
+    ?assertEqual({ok, [{xml_element_start, <<"test">>, []}]},
                  exml:parse(Parser, <<"<test>">>, false)),
     ?assertEqual(ok, exml:free_parser(Parser)).
 
 cdata_test() ->
     {ok, Parser} = exml:new_parser(),
 
-    ?assertEqual([{xml_element_start, <<"test">>, []},
-                  {xml_cdata, <<"some_cdata stuff">>},
-                  {xml_element_end, <<"test">>}],
+    ?assertEqual({ok, [{xml_element_start, <<"test">>, []},
+                       {xml_cdata, <<"some_cdata stuff">>},
+                       {xml_element_end, <<"test">>}]},
                  exml:parse(Parser, <<"<test>some_cdata stuff</test>">>, true)),
     ?assertEqual(ok, exml:free_parser(Parser)).