Merge pull request #390 from besser82/json-c-0.13

json_object: Add const size_t json_c_object_sizeof()

json_object.c

@@ -509,6 +509,11 @@ int json_object_object_length(const struct json_object *jso)
 	return lh_table_length(jso->o.c_object);
 }
 
+size_t json_c_object_sizeof(void)
+{
+	return sizeof(struct json_object);
+}
+
 struct json_object* json_object_object_get(const struct json_object* jso,
 					   const char *key)
 {

json_object.h

@@ -27,6 +27,12 @@
 #define THIS_FUNCTION_IS_DEPRECATED(func) func
 #endif
 
+#ifdef __GNUC__
+#define JSON_C_CONST_FUNCTION(func) func __attribute__((const))
+#else
+#define CONST_FUNCTION(func) func
+#endif
+
 #if defined(_MSC_VER) 
 #define JSON_EXPORT __declspec(dllexport)
 #else
@@ -392,6 +398,11 @@ JSON_EXPORT struct lh_table* json_object_get_object(const struct json_object *ob
  */
 JSON_EXPORT int json_object_object_length(const struct json_object* obj);
 
+/** Get the sizeof (struct json_object).
+ * @returns a size_t with the sizeof (struct json_object)
+ */
+JSON_C_CONST_FUNCTION(JSON_EXPORT size_t json_c_object_sizeof(void));
+
 /** Add an object field to a json_object of type json_type_object
  *
  * The reference count will *not* be incremented. This is to make adding