1 files changed, 94 insertions, 6 deletions
diff --git a/src/mochiweb/mochijson2.erl b/src/mochiweb/mochijson2.erl
index 9b59c7df..8bfd23c8 100644
--- a/src/mochiweb/mochijson2.erl
+++ b/src/mochiweb/mochijson2.erl
@@ -132,13 +132,81 @@ json_encode_proplist(Props, State) ->
     lists:reverse([$\} | Acc1]).
 
 json_encode_string(A, _State) when is_atom(A) ->
-    json_encode_string_unicode(xmerl_ucs:from_utf8(atom_to_list(A)), [?Q]);
+    L = atom_to_list(A),
+    case json_string_is_safe(L) of
+        true ->
+            [?Q, L, ?Q];
+        false ->
+            json_encode_string_unicode(xmerl_ucs:from_utf8(L), [?Q])
+    end;
 json_encode_string(B, _State) when is_binary(B) ->
-    json_encode_string_unicode(xmerl_ucs:from_utf8(B), [?Q]);
+    case json_bin_is_safe(B) of
+        true ->
+            [?Q, B, ?Q];
+        false ->
+            json_encode_string_unicode(xmerl_ucs:from_utf8(B), [?Q])
+    end;
 json_encode_string(I, _State) when is_integer(I) ->
-    json_encode_string_unicode(integer_to_list(I), [?Q]);
+    [?Q, integer_to_list(I), ?Q];
 json_encode_string(L, _State) when is_list(L) ->
-    json_encode_string_unicode(L, [?Q]).
+    case json_string_is_safe(L) of
+        true ->
+            [?Q, L, ?Q];
+        false ->
+            json_encode_string_unicode(L, [?Q])
+    end.
+
+json_string_is_safe([]) ->
+    true;
+json_string_is_safe([C | Rest]) ->
+    case C of
+        ?Q ->
+            false;
+        $\\ ->
+            false;
+        $\b ->
+            false;
+        $\f ->
+            false;
+        $\n ->
+            false;
+        $\r ->
+            false;
+        $\t ->
+            false;
+        C when C >= 0, C < $\s; C >= 16#7f, C =< 16#10FFFF ->
+            false;
+        C when C < 16#7f ->
+            json_string_is_safe(Rest);
+        _ ->
+            false
+    end.
+
+json_bin_is_safe(<<>>) ->
+    true;
+json_bin_is_safe(<<C, Rest/binary>>) ->
+    case C of
+        ?Q ->
+            false;
+        $\\ ->
+            false;
+        $\b ->
+            false;
+        $\f ->
+            false;
+        $\n ->
+            false;
+        $\r ->
+            false;
+        $\t ->
+            false;
+        C when C >= 0, C < $\s; C >= 16#7f, C =< 16#10FFFF ->
+            false;
+        C when C < 16#7f ->
+            json_bin_is_safe(Rest);
+        _ ->
+            false
+    end.
 
 json_encode_string_unicode([], Acc) ->
     lists:reverse([$\" | Acc]);
@@ -260,8 +328,28 @@ decode_array(B, S=#decoder{state=comma}, Acc) ->
             decode_array(B, S1#decoder{state=any}, Acc)
     end.
 
-tokenize_string(B, S) ->
-    tokenize_string(B, S, []).
+tokenize_string(B, S=#decoder{offset=O}) ->
+    case tokenize_string_fast(B, O) of
+        {escape, O1} ->
+            Length = O1 - O,
+            S1 = ?ADV_COL(S, Length),
+            <<_:O/binary, Head:Length/binary, _/binary>> = B,
+            tokenize_string(B, S1, lists:reverse(binary_to_list(Head)));
+        O1 ->
+            Length = O1 - O,
+            <<_:O/binary, String:Length/binary, ?Q, _/binary>> = B,
+            {{const, String}, ?ADV_COL(S, Length + 1)}
+    end.
+
+tokenize_string_fast(B, O) ->
+    case B of
+        <<_:O/binary, ?Q, _/binary>> ->
+            O;
+        <<_:O/binary, C, _/binary>> when C =/= $\\ ->
+            tokenize_string_fast(B, 1 + O);
+        _ ->
+            {escape, O}
+    end.
 
 tokenize_string(B, S=#decoder{offset=O}, Acc) ->
     case B of