Imported Upstream version 2.6.7

[platform/upstream/harfbuzz.git] / src / hb-meta.hh

diff --git a/src/hb-meta.hh b/src/hb-meta.hh
index 2dfaeb7..c08b191 100644 (file)
--- a/src/hb-meta.hh
+++ b/src/hb-meta.hh
@@ -396,5 +396,16 @@ using hb_is_trivial= hb_bool_constant<
 >;
 #define hb_is_trivial(T) hb_is_trivial<T>::value
 
+/* hb_unwrap_type (T)
+ * If T has no T::type, returns T. Otherwise calls itself on T::type recursively.
+ */
+
+template <typename T, typename>
+struct _hb_unwrap_type : hb_type_identity_t<T> {};
+template <typename T>
+struct _hb_unwrap_type<T, hb_void_t<typename T::type>> : _hb_unwrap_type<typename T::type, void> {};
+template <typename T>
+using hb_unwrap_type = _hb_unwrap_type<T, void>;
+#define hb_unwrap_type(T) typename hb_unwrap_type<T>::type
 
 #endif /* HB_META_HH */