re PR libstdc++/66693 ([C++17] std::tuple_size fails with const std::array)

[thirdparty/gcc.git] / libstdc++-v3 / include / std / utility

diff --git a/libstdc++-v3/include/std/utility b/libstdc++-v3/include/std/utility
index 985bcb202156802792a0f5a1f5ac1403f316c64e..2115d73cac6524501c8dab1d3b98c72ce2f40003 100644 (file)
--- a/libstdc++-v3/include/std/utility
+++ b/libstdc++-v3/include/std/utility
@@ -79,11 +79,56 @@ namespace std _GLIBCXX_VISIBILITY(default)
 {
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
-  template<class _Tp>
-    class tuple_size;
+  /// Finds the size of a given tuple type.
+  template<typename _Tp>
+    struct tuple_size;
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2313. tuple_size should always derive from integral_constant<size_t, N>
+  template<typename _Tp>
+    struct tuple_size<const _Tp>
+    : integral_constant<size_t, tuple_size<_Tp>::value> { };
+
+  template<typename _Tp>
+    struct tuple_size<volatile _Tp>
+    : integral_constant<size_t, tuple_size<_Tp>::value> { };
+
+  template<typename _Tp>
+    struct tuple_size<const volatile _Tp>
+    : integral_constant<size_t, tuple_size<_Tp>::value> { };
+
+  /// Gives the type of the ith element of a given tuple type.
+  template<std::size_t __i, typename _Tp>
+    struct tuple_element;
+
+  // Duplicate of C++14's tuple_element_t for internal use in C++11 mode
+  template<std::size_t __i, typename _Tp>
+    using __tuple_element_t = typename tuple_element<__i, _Tp>::type;
+
+  template<std::size_t __i, typename _Tp>
+    struct tuple_element<__i, const _Tp>
+    {
+      typedef typename add_const<__tuple_element_t<__i, _Tp>>::type type;
+    };
+
+  template<std::size_t __i, typename _Tp>
+    struct tuple_element<__i, volatile _Tp>
+    {
+      typedef typename add_volatile<__tuple_element_t<__i, _Tp>>::type type;
+    };
 
-  template<std::size_t _Int, class _Tp>
-    class tuple_element;
+  template<std::size_t __i, typename _Tp>
+    struct tuple_element<__i, const volatile _Tp>
+    {
+      typedef typename add_cv<__tuple_element_t<__i, _Tp>>::type type;
+    };
+
+#if __cplusplus > 201103L
+#define __cpp_lib_tuple_element_t 201402
+
+  template<std::size_t __i, typename _Tp>
+    using tuple_element_t = typename tuple_element<__i, _Tp>::type;
+#endif
 
   template<typename>
     struct __is_tuple_like_impl : false_type