libstdc++
|
00001 // Uses-allocator Construction -*- C++ -*- 00002 00003 // Copyright (C) 2010-2019 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 #ifndef _USES_ALLOCATOR_H 00026 #define _USES_ALLOCATOR_H 1 00027 00028 #if __cplusplus < 201103L 00029 # include <bits/c++0x_warning.h> 00030 #else 00031 00032 #include <type_traits> 00033 #include <bits/move.h> 00034 00035 namespace std _GLIBCXX_VISIBILITY(default) 00036 { 00037 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00038 00039 // This is used for std::experimental::erased_type from Library Fundamentals. 00040 struct __erased_type { }; 00041 00042 // This also supports the "type-erased allocator" protocol from the 00043 // Library Fundamentals TS, where allocator_type is erased_type. 00044 // The second condition will always be false for types not using the TS. 00045 template<typename _Alloc, typename _Tp> 00046 using __is_erased_or_convertible 00047 = __or_<is_convertible<_Alloc, _Tp>, is_same<_Tp, __erased_type>>; 00048 00049 /// [allocator.tag] 00050 struct allocator_arg_t { explicit allocator_arg_t() = default; }; 00051 00052 _GLIBCXX17_INLINE constexpr allocator_arg_t allocator_arg = 00053 allocator_arg_t(); 00054 00055 template<typename _Tp, typename _Alloc, typename = __void_t<>> 00056 struct __uses_allocator_helper 00057 : false_type { }; 00058 00059 template<typename _Tp, typename _Alloc> 00060 struct __uses_allocator_helper<_Tp, _Alloc, 00061 __void_t<typename _Tp::allocator_type>> 00062 : __is_erased_or_convertible<_Alloc, typename _Tp::allocator_type>::type 00063 { }; 00064 00065 /// [allocator.uses.trait] 00066 template<typename _Tp, typename _Alloc> 00067 struct uses_allocator 00068 : __uses_allocator_helper<_Tp, _Alloc>::type 00069 { }; 00070 00071 struct __uses_alloc_base { }; 00072 00073 struct __uses_alloc0 : __uses_alloc_base 00074 { 00075 struct _Sink { void operator=(const void*) { } } _M_a; 00076 }; 00077 00078 template<typename _Alloc> 00079 struct __uses_alloc1 : __uses_alloc_base { const _Alloc* _M_a; }; 00080 00081 template<typename _Alloc> 00082 struct __uses_alloc2 : __uses_alloc_base { const _Alloc* _M_a; }; 00083 00084 template<bool, typename _Tp, typename _Alloc, typename... _Args> 00085 struct __uses_alloc; 00086 00087 template<typename _Tp, typename _Alloc, typename... _Args> 00088 struct __uses_alloc<true, _Tp, _Alloc, _Args...> 00089 : conditional< 00090 is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>::value, 00091 __uses_alloc1<_Alloc>, 00092 __uses_alloc2<_Alloc>>::type 00093 { 00094 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00095 // 2586. Wrong value category used in scoped_allocator_adaptor::construct 00096 static_assert(__or_< 00097 is_constructible<_Tp, allocator_arg_t, const _Alloc&, _Args...>, 00098 is_constructible<_Tp, _Args..., const _Alloc&>>::value, 00099 "construction with an allocator must be possible" 00100 " if uses_allocator is true"); 00101 }; 00102 00103 template<typename _Tp, typename _Alloc, typename... _Args> 00104 struct __uses_alloc<false, _Tp, _Alloc, _Args...> 00105 : __uses_alloc0 { }; 00106 00107 template<typename _Tp, typename _Alloc, typename... _Args> 00108 using __uses_alloc_t = 00109 __uses_alloc<uses_allocator<_Tp, _Alloc>::value, _Tp, _Alloc, _Args...>; 00110 00111 template<typename _Tp, typename _Alloc, typename... _Args> 00112 inline __uses_alloc_t<_Tp, _Alloc, _Args...> 00113 __use_alloc(const _Alloc& __a) 00114 { 00115 __uses_alloc_t<_Tp, _Alloc, _Args...> __ret; 00116 __ret._M_a = std::__addressof(__a); 00117 return __ret; 00118 } 00119 00120 template<typename _Tp, typename _Alloc, typename... _Args> 00121 void 00122 __use_alloc(const _Alloc&&) = delete; 00123 00124 #if __cplusplus > 201402L 00125 template <typename _Tp, typename _Alloc> 00126 inline constexpr bool uses_allocator_v = 00127 uses_allocator<_Tp, _Alloc>::value; 00128 #endif // C++17 00129 00130 template<template<typename...> class _Predicate, 00131 typename _Tp, typename _Alloc, typename... _Args> 00132 struct __is_uses_allocator_predicate 00133 : conditional<uses_allocator<_Tp, _Alloc>::value, 00134 __or_<_Predicate<_Tp, allocator_arg_t, _Alloc, _Args...>, 00135 _Predicate<_Tp, _Args..., _Alloc>>, 00136 _Predicate<_Tp, _Args...>>::type { }; 00137 00138 template<typename _Tp, typename _Alloc, typename... _Args> 00139 struct __is_uses_allocator_constructible 00140 : __is_uses_allocator_predicate<is_constructible, _Tp, _Alloc, _Args...> 00141 { }; 00142 00143 #if __cplusplus >= 201402L 00144 template<typename _Tp, typename _Alloc, typename... _Args> 00145 _GLIBCXX17_INLINE constexpr bool __is_uses_allocator_constructible_v = 00146 __is_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; 00147 #endif // C++14 00148 00149 template<typename _Tp, typename _Alloc, typename... _Args> 00150 struct __is_nothrow_uses_allocator_constructible 00151 : __is_uses_allocator_predicate<is_nothrow_constructible, 00152 _Tp, _Alloc, _Args...> 00153 { }; 00154 00155 00156 #if __cplusplus >= 201402L 00157 template<typename _Tp, typename _Alloc, typename... _Args> 00158 _GLIBCXX17_INLINE constexpr bool 00159 __is_nothrow_uses_allocator_constructible_v = 00160 __is_nothrow_uses_allocator_constructible<_Tp, _Alloc, _Args...>::value; 00161 #endif // C++14 00162 00163 template<typename _Tp, typename... _Args> 00164 void __uses_allocator_construct_impl(__uses_alloc0 __a, _Tp* __ptr, 00165 _Args&&... __args) 00166 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)...); } 00167 00168 template<typename _Tp, typename _Alloc, typename... _Args> 00169 void __uses_allocator_construct_impl(__uses_alloc1<_Alloc> __a, _Tp* __ptr, 00170 _Args&&... __args) 00171 { 00172 ::new ((void*)__ptr) _Tp(allocator_arg, *__a._M_a, 00173 std::forward<_Args>(__args)...); 00174 } 00175 00176 template<typename _Tp, typename _Alloc, typename... _Args> 00177 void __uses_allocator_construct_impl(__uses_alloc2<_Alloc> __a, _Tp* __ptr, 00178 _Args&&... __args) 00179 { ::new ((void*)__ptr) _Tp(std::forward<_Args>(__args)..., *__a._M_a); } 00180 00181 template<typename _Tp, typename _Alloc, typename... _Args> 00182 void __uses_allocator_construct(const _Alloc& __a, _Tp* __ptr, 00183 _Args&&... __args) 00184 { 00185 std::__uses_allocator_construct_impl( 00186 std::__use_alloc<_Tp, _Alloc, _Args...>(__a), __ptr, 00187 std::forward<_Args>(__args)...); 00188 } 00189 00190 _GLIBCXX_END_NAMESPACE_VERSION 00191 } // namespace std 00192 00193 #endif 00194 #endif