1 // Uses-allocator Construction -*- C++ -*- 2 3 // Copyright (C) 2010-2019 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 // This is used for std::experimental::erased_type from Library Fundamentals. 40 struct __erased_type { }; 41 42 // This also supports the "type-erased allocator" protocol from the 43 // Library Fundamentals TS, where allocator_type is erased_type. 44 // The second condition will always be false for types not using the TS. 45 template<typename _Alloc, typename _Tp> 46 using __is_erased_or_convertible 47 = __or_<is_convertible<_Alloc, _Tp>, is_same<_Tp, __erased_type>>; 48 49 /// [allocator.tag] 50 struct allocator_arg_t { explicit allocator_arg_t() = default; }; 51 52 _GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg = 53 allocator_arg_t(); 54 55 template<typename _Tp, typename _Alloc, typename = __void_t<>> 56 struct __uses_allocator_helper 57 : false_type { }; 58 59 template<typename _Tp, typename _Alloc> 60 struct __uses_allocator_helper<_Tp, _Alloc, 61 __void_t<typename _Tp::allocator_type>> 62 : __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type 63 { }; 64 65 /// [allocator.uses.trait] 66 template<typename _Tp, typename _Alloc> 67 struct uses_allocator 68 : __uses_allocator_helper<_Tp, _Alloc>::type 69 { }; 70 71 struct __uses_alloc_base { }; 72 73 struct __uses_alloc0 : __uses_alloc_base 74 { 75 struct _Sink { void operator=(const void*) { } } _M_a; 76 }; 77 78 template<typename _Alloc> 79 struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; }; 80 81 template<typename _Alloc> 82 struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; }; 83 84 template<bool, typename _Tp, typename _Alloc, typename... _Args> 85 struct __uses_alloc; 86 87 template<typename _Tp, typename _Alloc, typename... _Args> 88 struct __uses_alloc<true, _Tp, _Alloc, _Args...> 89 : conditional< 90 is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>::value, 91 __uses_alloc1<_Alloc>, 92 __uses_alloc2<_Alloc>>::type 93 { 94 // _GLIBCXX_RESOLVE_LIB_DEFECTS 95 // 2586. Wrong value category used in scoped_allocator_adaptor::construct 96 static_assert(__or_< 97 is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>, 98 is_constructible<_Tp, _Args..., const _Alloc&>>::value, 99 "construction with an allocator must be possible" 100 " if uses_allocator is true"); 101 }; 102 103 template<typename _Tp, typename _Alloc, typename... _Args> 104 struct __uses_alloc<false, _Tp, _Alloc, _Args...> 105 : __uses_alloc0 { }; 106 107 template<typename _Tp, typename _Alloc, typename... _Args> 108 using __uses_alloc_t = 109 __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>; 110 111 template<typename _Tp, typename _Alloc, typename... _Args> 112 inline __uses_alloc_t<_Tp, _Alloc, _Args...> 113 __use_alloc(const _Alloc& __a) 114 { 115 __uses_alloc_t<_Tp, _Alloc, _Args...> __ret; 116 __ret._M_a = std::__addressof(__a); 117 return __ret; 118 } 119 120 template<typename _Tp, typename _Alloc, typename... _Args> 121 void 122 __use_alloc(const _Alloc&&) = delete; 123 124 #if __cplusplus > 201402L 125 template <typename _Tp, typename _Alloc> 126 inline constexpr bool uses_allocator_v = 127 uses_allocator<_Tp, _Alloc>::value; 128 #endif // C++17 129 130 template<template<typename...> class _Predicate, 131 typename _Tp, typename _Alloc, typename... _Args> 132 struct __is_uses_allocator_predicate 133 : conditional<uses_allocator<_Tp, _Alloc>::value, 134 __or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>, 135 _Predicate<_Tp, _Args..., _Alloc>>, 136 _Predicate<_Tp, _Args...>>::type { }; 137 138 template<typename _Tp, typename _Alloc, typename... _Args> 139 struct __is_uses_allocator_constructible 140 : __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...> 141 { }; 142 143 #if __cplusplus >= 201402L 144 template<typename _Tp, typename _Alloc, typename... _Args> 145 _GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v = 146 __is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; 147 #endif // C++14 148 149 template<typename _Tp, typename _Alloc, typename... _Args> 150 struct __is_nothrow_uses_allocator_constructible 151 : __is_uses_allocator_predicate<is_nothrow_constructible, 152 _Tp, _Alloc, _Args...> 153 { }; 154 155 156 #if __cplusplus >= 201402L 157 template<typename _Tp, typename _Alloc, typename... _Args> 158 _GLIBCXX17_INLINE constexpr bool 159 __is_nothrow_uses_allocator_constructible_v = 160 __is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; 161 #endif // C++14 162 163 template<typename _Tp, typename... _Args> 164 void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr, 165 _Args&&... __args) 166 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); } 167 168 template<typename _Tp, typename _Alloc, typename... _Args> 169 void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr, 170 _Args&&... __args) 171 { 172 ::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a, 173 std::forward<_Args>(__args)...); 174 } 175 176 template<typename _Tp, typename _Alloc, typename... _Args> 177 void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr, 178 _Args&&... __args) 179 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); } 180 181 template<typename _Tp, typename _Alloc, typename... _Args> 182 void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr, 183 _Args&&... __args) 184 { 185 std::__uses_allocator_construct_impl( 186 std::__use_alloc<_Tp, _Alloc, _Args...>(__a), __ptr, 187 std::forward<_Args>(__args)...); 188 } 189 190 _GLIBCXX_END_NAMESPACE_VERSION 191 } // namespace std 192 193 #endif 194 #endif 195