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
23template <class _Tp>
24struct __has_allocator_type
25{
26private:
27    template <class _Up> static false_type __test(...);
28    template <class _Up> static true_type __test(typename _Up::allocator_type* = 0);
29public:
30    static const bool value = decltype(__test<_Tp>(0))::value;
31};
32
33template <class _Tp, class _Alloc, bool = __has_allocator_type<_Tp>::value>
34struct __uses_allocator
35    : public integral_constant<bool,
36        is_convertible<_Alloc, typename _Tp::allocator_type>::value>
37{
38};
39
40template <class _Tp, class _Alloc>
41struct __uses_allocator<_Tp, _Alloc, false>
42    : public false_type
43{
44};
45
46template <class _Tp, class _Alloc>
47struct _LIBCPP_TEMPLATE_VIS uses_allocator
48    : public __uses_allocator<_Tp, _Alloc>
49{
50};
51
52#if _LIBCPP_STD_VER > 14
53template <class _Tp, class _Alloc>
54inline constexpr size_t uses_allocator_v = uses_allocator<_Tp, _Alloc>::value;
55#endif
56
57_LIBCPP_END_NAMESPACE_STD
58
59#endif // _LIBCPP___MEMORY_USES_ALLOCATOR_H
60