recognize [with_trailer] option, but do not use yet

c_src/decoder.c

@@ -53,6 +53,7 @@ typedef struct {
     int             is_partial;
     int             return_maps;
     int             use_nil;
+    int             with_trailer;
 
     char*           p;
     unsigned char*  u;
@@ -81,6 +82,7 @@ dec_new(ErlNifEnv* env)
     d->is_partial = 0;
     d->return_maps = 0;
     d->use_nil = 0;
+    d->with_trailer = 0;
 
     d->p = NULL;
     d->u = NULL;
@@ -712,6 +714,8 @@ decode_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 #endif
         } else if(enif_compare(val, d->atoms->atom_use_nil) == 0) {
             d->use_nil = 1;
+        } else if(enif_compare(val, d->atoms->atom_with_trailer) == 0) {
+            d->with_trailer = 1;
         } else {
             return enif_make_badarg(env);
         }

c_src/jiffy.c

@@ -28,6 +28,7 @@ load(ErlNifEnv* env, void** priv, ERL_NIF_TERM info)
     st->atom_return_maps = make_atom(env, "return_maps");
     st->atom_nil = make_atom(env, "nil");
     st->atom_use_nil = make_atom(env, "use_nil");
+    st->atom_with_trailer = make_atom(env, "with_trailer");
 
     // Markers used in encoding
     st->ref_object = make_atom(env, "$object_ref$");

c_src/jiffy.h

@@ -42,6 +42,7 @@ typedef struct {
     ERL_NIF_TERM    atom_return_maps;
     ERL_NIF_TERM    atom_nil;
     ERL_NIF_TERM    atom_use_nil;
+    ERL_NIF_TERM    atom_with_trailer;
 
     ERL_NIF_TERM    ref_object;
     ERL_NIF_TERM    ref_array;

src/jiffy.erl

@@ -19,13 +19,23 @@ decode(Data, Opts) when is_binary(Data), is_list(Opts) ->
         {partial, EJson} ->
             finish_decode(EJson);
         {iter, Decoder, Val, Objs, Curr} ->
-            decode_loop(Data, Decoder, Val, Objs, Curr);
+            trailer_or_error(decode_loop(Data, Decoder, Val, Objs, Curr), Opts, Data);
         EJson ->
             EJson
     end;
 decode(Data, Opts) when is_list(Data) ->
     decode(iolist_to_binary(Data), Opts).
 
+% Only return trailing data if explicitly requested in the options.
+trailer_or_error({with_trailer, _EJson, TrailerData} = WithTrailer, Opts, Data) ->
+    case lists:member(with_trailer, Opts) of
+        true -> WithTrailer;
+        false ->
+            AtByte = iolist_size(Data) - iolist_size(TrailerData) + 1,
+            throw({error,{AtByte,invalid_trailing_data}})
+    end;
+trailer_or_error(EJson, _Opts, _Data) -> EJson.
+
 
 encode(Data) ->
     encode(Data, []).

test/jiffy_15_trailer_tests.erl

@@ -0,0 +1,11 @@
+% This file is part of Jiffy released under the MIT license.
+% See the LICENSE file for more information.
+
+-module(jiffy_15_trailer_tests).
+
+-include_lib("eunit/include/eunit.hrl").
+
+trailer_test_() ->
+   {"trailer", [
+        ?_assertEqual(true, jiffy:decode(<<"true">>, [with_trailer]))
+    ]}.