1 // Allocators -*- C++ -*- 2 3 // Copyright (C) 2001-2018 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 /* 26 * Copyright (c) 1996-1997 27 * Silicon Graphics Computer Systems, Inc. 28 * 29 * Permission to use, copy, modify, distribute and sell this software 30 * and its documentation for any purpose is hereby granted without fee, 31 * provided that the above copyright notice appear in all copies and 32 * that both that copyright notice and this permission notice appear 33 * in supporting documentation. Silicon Graphics makes no 34 * representations about the suitability of this software for any 35 * purpose. It is provided "as is" without express or implied warranty. 36 */ 37 38 /** @file bits/allocator.h 39 * This is an internal header file, included by other library headers. 40 * Do not attempt to use it directly. @headername{memory} 41 */ 42 43 #ifndef _ALLOCATOR_H 44 #define _ALLOCATOR_H 1 45 46 #include <bits/c++allocator.h> // Define the base class to std::allocator. 47 #include <bits/memoryfwd.h> 48 #if __cplusplus >= 201103L 49 #include <type_traits> 50 #endif 51 52 #define __cpp_lib_incomplete_container_elements 201505 53 #if __cplusplus >= 201103L 54 # define __cpp_lib_allocator_is_always_equal 201411 55 #endif 56 57 namespace std _GLIBCXX_VISIBILITY(default) 58 { 59 _GLIBCXX_BEGIN_NAMESPACE_VERSION 60 61 /** 62 * @addtogroup allocators 63 * @{ 64 */ 65 66 /// allocator<void> specialization. 67 template<> 68 class allocator<void> 69 { 70 public: 71 typedef size_t size_type; 72 typedef ptrdiff_t difference_type; 73 typedef void* pointer; 74 typedef const void* const_pointer; 75 typedef void value_type; 76 77 template<typename _Tp1> 78 struct rebind 79 { typedef allocator<_Tp1> other; }; 80 81 #if __cplusplus >= 201103L 82 // _GLIBCXX_RESOLVE_LIB_DEFECTS 83 // 2103. std::allocator propagate_on_container_move_assignment 84 typedef true_type propagate_on_container_move_assignment; 85 86 typedef true_type is_always_equal; 87 88 template<typename _Up, typename... _Args> 89 void 90 construct(_Up* __p, _Args&&... __args) 91 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 92 93 template<typename _Up> 94 void 95 destroy(_Up* __p) { __p->~_Up(); } 96 #endif 97 }; 98 99 /** 100 * @brief The @a standard allocator, as per [20.4]. 101 * 102 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator 103 * for further details. 104 * 105 * @tparam _Tp Type of allocated object. 106 */ 107 template<typename _Tp> 108 class allocator : public __allocator_base<_Tp> 109 { 110 public: 111 typedef size_t size_type; 112 typedef ptrdiff_t difference_type; 113 typedef _Tp* pointer; 114 typedef const _Tp* const_pointer; 115 typedef _Tp& reference; 116 typedef const _Tp& const_reference; 117 typedef _Tp value_type; 118 119 template<typename _Tp1> 120 struct rebind 121 { typedef allocator<_Tp1> other; }; 122 123 #if __cplusplus >= 201103L 124 // _GLIBCXX_RESOLVE_LIB_DEFECTS 125 // 2103. std::allocator propagate_on_container_move_assignment 126 typedef true_type propagate_on_container_move_assignment; 127 128 typedef true_type is_always_equal; 129 #endif 130 131 allocator() throw() { } 132 133 allocator(const allocator& __a) throw() 134 : __allocator_base<_Tp>(__a) { } 135 136 template<typename _Tp1> 137 allocator(const allocator<_Tp1>&) throw() { } 138 139 ~allocator() throw() { } 140 141 // Inherit everything else. 142 }; 143 144 template<typename _T1, typename _T2> 145 inline bool 146 operator==(const allocator<_T1>&, const allocator<_T2>&) 147 _GLIBCXX_USE_NOEXCEPT 148 { return true; } 149 150 template<typename _Tp> 151 inline bool 152 operator==(const allocator<_Tp>&, const allocator<_Tp>&) 153 _GLIBCXX_USE_NOEXCEPT 154 { return true; } 155 156 template<typename _T1, typename _T2> 157 inline bool 158 operator!=(const allocator<_T1>&, const allocator<_T2>&) 159 _GLIBCXX_USE_NOEXCEPT 160 { return false; } 161 162 template<typename _Tp> 163 inline bool 164 operator!=(const allocator<_Tp>&, const allocator<_Tp>&) 165 _GLIBCXX_USE_NOEXCEPT 166 { return false; } 167 168 // Invalid allocator<cv T> partial specializations. 169 // allocator_traits::rebind_alloc can be used to form a valid allocator type. 170 template<typename _Tp> 171 class allocator<const _Tp> 172 { 173 public: 174 typedef _Tp value_type; 175 template<typename _Up> allocator(const allocator<_Up>&) { } 176 }; 177 178 template<typename _Tp> 179 class allocator<volatile _Tp> 180 { 181 public: 182 typedef _Tp value_type; 183 template<typename _Up> allocator(const allocator<_Up>&) { } 184 }; 185 186 template<typename _Tp> 187 class allocator<const volatile _Tp> 188 { 189 public: 190 typedef _Tp value_type; 191 template<typename _Up> allocator(const allocator<_Up>&) { } 192 }; 193 194 /// @} group allocator 195 196 // Inhibit implicit instantiations for required instantiations, 197 // which are defined via explicit instantiations elsewhere. 198 #if _GLIBCXX_EXTERN_TEMPLATE 199 extern template class allocator<char>; 200 extern template class allocator<wchar_t>; 201 #endif 202 203 // Undefine. 204 #undef __allocator_base 205 206 // To implement Option 3 of DR 431. 207 template<typename _Alloc, bool = __is_empty(_Alloc)> 208 struct __alloc_swap 209 { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } }; 210 211 template<typename _Alloc> 212 struct __alloc_swap<_Alloc, false> 213 { 214 static void 215 _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT 216 { 217 // Precondition: swappable allocators. 218 if (__one != __two) 219 swap(__one, __two); 220 } 221 }; 222 223 // Optimize for stateless allocators. 224 template<typename _Alloc, bool = __is_empty(_Alloc)> 225 struct __alloc_neq 226 { 227 static bool 228 _S_do_it(const _Alloc&, const _Alloc&) 229 { return false; } 230 }; 231 232 template<typename _Alloc> 233 struct __alloc_neq<_Alloc, false> 234 { 235 static bool 236 _S_do_it(const _Alloc& __one, const _Alloc& __two) 237 { return __one != __two; } 238 }; 239 240 #if __cplusplus >= 201103L 241 template<typename _Tp, bool 242 = __or_<is_copy_constructible<typename _Tp::value_type>, 243 is_nothrow_move_constructible<typename _Tp::value_type>>::value> 244 struct __shrink_to_fit_aux 245 { static bool _S_do_it(_Tp&) noexcept { return false; } }; 246 247 template<typename _Tp> 248 struct __shrink_to_fit_aux<_Tp, true> 249 { 250 static bool 251 _S_do_it(_Tp& __c) noexcept 252 { 253 #if __cpp_exceptions 254 try 255 { 256 _Tp(__make_move_if_noexcept_iterator(__c.begin()), 257 __make_move_if_noexcept_iterator(__c.end()), 258 __c.get_allocator()).swap(__c); 259 return true; 260 } 261 catch(...) 262 { return false; } 263 #else 264 return false; 265 #endif 266 } 267 }; 268 #endif 269 270 _GLIBCXX_END_NAMESPACE_VERSION 271 } // namespace std 272 273 #endif 274