Add simple method to add default values for missing deserialized fields.…

Add simple method to add default values for missing deserialized fields. Provided to ease backwards compatibility. (#547)

src/ngraph/serializer.cpp

@@ -372,7 +372,7 @@ static shared_ptr<ngraph::Function>
             auto padding_below = node_js.at("padding_below").get<vector<size_t>>();
             auto padding_above = node_js.at("padding_above").get<vector<size_t>>();
             auto include_padding_in_avg_computation =
-                node_js.at("include_padding_in_avg_computation").get<bool>();
+                get_or_default<bool>(node_js, "include_padding_in_avg_computation", false);
             node = make_shared<op::AvgPoolBackprop>(forward_arg_shape,
                                                     args[0],
                                                     window_shape,

src/ngraph/serializer.hpp

@@ -28,4 +28,19 @@ namespace ngraph
     std::string serialize(std::shared_ptr<ngraph::Function>, size_t indent = 0);
     std::shared_ptr<ngraph::Function> deserialize(std::istream&);
     std::shared_ptr<ngraph::Function> deserialize(const std::string&);
+
+    template <typename T>
+    T get_or_default(nlohmann::json& j, const std::string& key, const T& default_value)
+    {
+        T rc;
+        try
+        {
+            rc = j.at(key).get<T>();
+        }
+        catch (...)
+        {
+            rc = default_value;
+        }
+        return rc;
+    }
 }

test/serialize.cpp

@@ -106,6 +106,18 @@ TEST(serialize, existing_models)
     }
 }
 
+TEST(serialize, default_value)
+{
+    json j = {{"test1", 1}, {"test2", 2}};
+
+    int x1 = j.at("test1").get<int>();
+    EXPECT_EQ(x1, 1);
+    int x2 = get_or_default<int>(j, "test2", 0);
+    EXPECT_EQ(x2, 2);
+    int x3 = get_or_default<int>(j, "test3", 3);
+    EXPECT_EQ(x3, 3);
+}
+
 TEST(benchmark, serialize)
 {
     stopwatch timer;