+ return static_cast<size_t>(hash::twang_mix64(key));
+ }
+};
+
+template<> struct hasher<std::string> {
+ size_t operator()(const std::string& key) const {
+ return static_cast<size_t>(
+ hash::SpookyHashV2::Hash64(key.data(), key.size(), 0));
+ }
+};
+
+template <class T>
+struct hasher<T, typename std::enable_if<std::is_enum<T>::value, void>::type> {
+ size_t operator()(T key) const {
+ return Hash()(static_cast<typename std::underlying_type<T>::type>(key));
+ }
+};
+
+template <class T1, class T2>
+struct hasher<std::pair<T1, T2>> {
+ size_t operator()(const std::pair<T1, T2>& key) const {
+ return Hash()(key.first, key.second);
+ }
+};
+
+template <typename... Ts>
+struct hasher<std::tuple<Ts...>> {
+ size_t operator() (const std::tuple<Ts...>& key) const {
+ return applyTuple(Hash(), key);