Implement the first part of N4258 - allocator_traits<X>::is_always_equal. Also fixes PR#23723 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@238848 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/memory b/include/memory index 4e3a6f8..dc5902d 100644 --- a/include/memory +++ b/include/memory
@@ -75,6 +75,8 @@ | false_type propagate_on_container_move_assignment; typedef Alloc::propagate_on_container_swap | false_type propagate_on_container_swap; + typedef Alloc::is_always_equal + | is_empty is_always_equal; template <class T> using rebind_alloc = Alloc::rebind<U>::other | Alloc<T, Args...>; template <class T> using rebind_traits = allocator_traits<rebind_alloc<T>>; @@ -1144,6 +1146,29 @@ typedef typename _Alloc::propagate_on_container_swap type; }; +template <class _Tp> +struct __has_is_always_equal +{ +private: + struct __two {char __lx; char __lxx;}; + template <class _Up> static __two __test(...); + template <class _Up> static char __test(typename _Up::is_always_equal* = 0); +public: + static const bool value = sizeof(__test<_Tp>(0)) == 1; +}; + +template <class _Alloc, bool = __has_is_always_equal<_Alloc>::value> +struct __is_always_equal +{ + typedef typename _VSTD::is_empty<_Alloc>::type type; +}; + +template <class _Alloc> +struct __is_always_equal<_Alloc, true> +{ + typedef typename _Alloc::is_always_equal type; +}; + template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value> struct __has_rebind_other { @@ -1423,6 +1448,8 @@ propagate_on_container_move_assignment; typedef typename __propagate_on_container_swap<allocator_type>::type propagate_on_container_swap; + typedef typename __is_always_equal<allocator_type>::type + is_always_equal; #ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES template <class _Tp> using rebind_alloc = @@ -1667,6 +1694,7 @@ typedef _Tp value_type; typedef true_type propagate_on_container_move_assignment; + typedef true_type is_always_equal; template <class _Up> struct rebind {typedef allocator<_Up> other;}; 