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 <cstddef> 15 #include <type_traits> 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 { 26 private: 27 struct __two {char __lx; char __lxx;}; 28 template <class _Up> static __two __test(...); 29 template <class _Up> static char __test(typename _Up::allocator_type* = 0); 30 public: 31 static const bool value = sizeof(__test<_Tp>(0)) == 1; 32 }; 33 34 template <class _Tp, class _Alloc, bool = __has_allocator_type<_Tp>::value> 35 struct __uses_allocator 36 : public integral_constant<bool, 37 is_convertible<_Alloc, typename _Tp::allocator_type>::value> 38 { 39 }; 40 41 template <class _Tp, class _Alloc> 42 struct __uses_allocator<_Tp, _Alloc, false> 43 : public false_type 44 { 45 }; 46 47 template <class _Tp, class _Alloc> 48 struct _LIBCPP_TEMPLATE_VIS uses_allocator 49 : public __uses_allocator<_Tp, _Alloc> 50 { 51 }; 52 53 #if _LIBCPP_STD_VER > 14 54 template <class _Tp, class _Alloc> 55 _LIBCPP_INLINE_VAR constexpr size_t uses_allocator_v = uses_allocator<_Tp, _Alloc>::value; 56 #endif 57 58 _LIBCPP_END_NAMESPACE_STD 59 60 #endif // _LIBCPP___MEMORY_USES_ALLOCATOR_H 61