Added helper methods to access struct through reflection. (#4120)
* Added helper methods to access struct through reflection. Also added unit test for it.
* Added a TODO comment to check for the is_struct flag.
diff --git a/include/flatbuffers/reflection.h b/include/flatbuffers/reflection.h
index 632acda..6d8608a 100644
--- a/include/flatbuffers/reflection.h
+++ b/include/flatbuffers/reflection.h
@@ -105,6 +105,22 @@
return table.GetPointer<Table *>(field.offset());
}
+// Get a field, if you know it's a struct.
+inline const Struct *GetFieldStruct(const Table &table,
+ const reflection::Field &field) {
+ // TODO: This does NOT check if the field is a table or struct, but we'd need
+ // access to the schema to check the is_struct flag.
+ assert(field.type()->base_type() == reflection::Obj);
+ return table.GetStruct<const Struct *>(field.offset());
+}
+
+// Get a structure's field, if you know it's a struct.
+inline const Struct *GetFieldStruct(const Struct &structure,
+ const reflection::Field &field) {
+ assert(field.type()->base_type() == reflection::Obj);
+ return structure.GetStruct<const Struct *>(field.offset());
+}
+
// Raw helper functions used below: get any value in memory as a 64bit int, a
// double or a string.
// All scalars get static_cast to an int64_t, strings use strtoull, every other
diff --git a/tests/test.cpp b/tests/test.cpp
index 4f44952..01d23e0 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -511,6 +511,20 @@
auto hp_string = flatbuffers::GetAnyFieldS(root, hp_field, &schema);
TEST_EQ_STR(hp_string.c_str(), "80");
+ // Get struct field through reflection
+ auto pos_struct = flatbuffers::GetFieldStruct(root, *pos_field_ptr);
+ TEST_NOTNULL(pos_struct);
+ TEST_EQ(flatbuffers::GetAnyFieldF(
+ *pos_struct, *pos_table_ptr->fields()->LookupByKey("z")), 3.0f);
+
+ auto test3_field = pos_table_ptr->fields()->LookupByKey("test3");
+ auto test3_struct = flatbuffers::GetFieldStruct(*pos_struct, *test3_field);
+ TEST_NOTNULL(test3_struct);
+ auto test3_object = schema.objects()->Get(test3_field->type()->index());
+
+ TEST_EQ(flatbuffers::GetAnyFieldF(
+ *test3_struct, *test3_object->fields()->LookupByKey("a")), 10);
+
// We can also modify it.
flatbuffers::SetField<uint16_t>(&root, hp_field, 200);
hp = flatbuffers::GetFieldI<uint16_t>(root, hp_field);
