1 // Uses-allocator Construction -*- C++ -*- 2 3 // Copyright (C) 2010-2018 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 #ifndef _USES_ALLOCATOR_H 26 #define _USES_ALLOCATOR_H 1 27 28 #if __cplusplus < 201103L 29 # include <bits/c++0x_warning.h> 30 #else 31 32 #include <type_traits> 33 #include <bits/move.h> 34 35 namespace std _GLIBCXX_VISIBILITY(default) 36 { 37 _GLIBCXX_BEGIN_NAMESPACE_VERSION 38 39 struct __erased_type { }; 40 41 template<typename _Alloc, typename _Tp> 42 using __is_erased_or_convertible 43 = __or_<is_same<_Tp, __erased_type>, is_convertible<_Alloc, _Tp>>; 44 45 /// [allocator.tag] 46 struct allocator_arg_t { explicit allocator_arg_t() = default; }; 47 48 _GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg = 49 allocator_arg_t(); 50 51 template<typename _Tp, typename _Alloc, typename = __void_t<>> 52 struct __uses_allocator_helper 53 : false_type { }; 54 55 template<typename _Tp, typename _Alloc> 56 struct __uses_allocator_helper<_Tp, _Alloc, 57 __void_t<typename _Tp::allocator_type>> 58 : __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type 59 { }; 60 61 /// [allocator.uses.trait] 62 template<typename _Tp, typename _Alloc> 63 struct uses_allocator 64 : __uses_allocator_helper<_Tp, _Alloc>::type 65 { }; 66 67 struct __uses_alloc_base { }; 68 69 struct __uses_alloc0 : __uses_alloc_base 70 { 71 struct _Sink { void operator=(const void*) { } } _M_a; 72 }; 73 74 template<typename _Alloc> 75 struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; }; 76 77 template<typename _Alloc> 78 struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; }; 79 80 template<bool, typename _Tp, typename _Alloc, typename... _Args> 81 struct __uses_alloc; 82 83 template<typename _Tp, typename _Alloc, typename... _Args> 84 struct __uses_alloc<true, _Tp, _Alloc, _Args...> 85 : conditional< 86 is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value, 87 __uses_alloc1<_Alloc>, 88 __uses_alloc2<_Alloc>>::type 89 { 90 static_assert(__or_< 91 is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>, 92 is_constructible<_Tp, _Args..., _Alloc>>::value, "construction with" 93 " an allocator must be possible if uses_allocator is true"); 94 }; 95 96 template<typename _Tp, typename _Alloc, typename... _Args> 97 struct __uses_alloc<false, _Tp, _Alloc, _Args...> 98 : __uses_alloc0 { }; 99 100 template<typename _Tp, typename _Alloc, typename... _Args> 101 using __uses_alloc_t = 102 __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>; 103 104 template<typename _Tp, typename _Alloc, typename... _Args> 105 inline __uses_alloc_t<_Tp, _Alloc, _Args...> 106 __use_alloc(const _Alloc& __a) 107 { 108 __uses_alloc_t<_Tp, _Alloc, _Args...> __ret; 109 __ret._M_a = std::__addressof(__a); 110 return __ret; 111 } 112 113 template<typename _Tp, typename _Alloc, typename... _Args> 114 void 115 __use_alloc(const _Alloc&&) = delete; 116 117 #if __cplusplus > 201402L 118 template <typename _Tp, typename _Alloc> 119 inline constexpr bool uses_allocator_v = 120 uses_allocator<_Tp, _Alloc>::value; 121 #endif // C++17 122 123 template<template<typename...> class _Predicate, 124 typename _Tp, typename _Alloc, typename... _Args> 125 struct __is_uses_allocator_predicate 126 : conditional<uses_allocator<_Tp, _Alloc>::value, 127 __or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>, 128 _Predicate<_Tp, _Args..., _Alloc>>, 129 _Predicate<_Tp, _Args...>>::type { }; 130 131 template<typename _Tp, typename _Alloc, typename... _Args> 132 struct __is_uses_allocator_constructible 133 : __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...> 134 { }; 135 136 #if __cplusplus >= 201402L 137 template<typename _Tp, typename _Alloc, typename... _Args> 138 _GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v = 139 __is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; 140 #endif // C++14 141 142 template<typename _Tp, typename _Alloc, typename... _Args> 143 struct __is_nothrow_uses_allocator_constructible 144 : __is_uses_allocator_predicate<is_nothrow_constructible, 145 _Tp, _Alloc, _Args...> 146 { }; 147 148 149 #if __cplusplus >= 201402L 150 template<typename _Tp, typename _Alloc, typename... _Args> 151 _GLIBCXX17_INLINE constexpr bool 152 __is_nothrow_uses_allocator_constructible_v = 153 __is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; 154 #endif // C++14 155 156 template<typename _Tp, typename... _Args> 157 void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr, 158 _Args&&... __args) 159 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); } 160 161 template<typename _Tp, typename _Alloc, typename... _Args> 162 void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr, 163 _Args&&... __args) 164 { 165 ::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a, 166 std::forward<_Args>(__args)...); 167 } 168 169 template<typename _Tp, typename _Alloc, typename... _Args> 170 void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr, 171 _Args&&... __args) 172 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); } 173 174 template<typename _Tp, typename _Alloc, typename... _Args> 175 void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr, 176 _Args&&... __args) 177 { 178 __uses_allocator_construct_impl(__use_alloc<_Tp, _Alloc, _Args...>(__a), 179 __ptr, std::forward<_Args>(__args)...); 180 } 181 182 _GLIBCXX_END_NAMESPACE_VERSION 183 } // namespace std 184 185 #endif 186 #endif 187