1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___MEMORY_USES_ALLOCATOR_H 11 #define _LIBCPP___MEMORY_USES_ALLOCATOR_H 12 13 #include <__config> 14 #include <__type_traits/is_convertible.h> 15 #include <cstddef> 16 17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 18 # pragma GCC system_header 19 #endif 20 21 _LIBCPP_BEGIN_NAMESPACE_STD 22 23 template <class _Tp> 24 struct __has_allocator_type { 25 private: 26 template <class _Up> 27 static false_type __test(...); 28 template <class _Up> 29 static true_type __test(typename _Up::allocator_type* = 0); 30 31 public: 32 static const bool value = decltype(__test<_Tp>(0))::value; 33 }; 34 35 template <class _Tp, class _Alloc, bool = __has_allocator_type<_Tp>::value> 36 struct __uses_allocator : public integral_constant<bool, is_convertible<_Alloc, typename _Tp::allocator_type>::value> { 37 }; 38 39 template <class _Tp, class _Alloc> 40 struct __uses_allocator<_Tp, _Alloc, false> : public false_type {}; 41 42 template <class _Tp, class _Alloc> 43 struct _LIBCPP_TEMPLATE_VIS uses_allocator : public __uses_allocator<_Tp, _Alloc> {}; 44 45 #if _LIBCPP_STD_VER >= 17 46 template <class _Tp, class _Alloc> 47 inline constexpr bool uses_allocator_v = uses_allocator<_Tp, _Alloc>::value; 48 #endif 49 50 _LIBCPP_END_NAMESPACE_STD 51 52 #endif // _LIBCPP___MEMORY_USES_ALLOCATOR_H 53