1 // Allocators -*- C++ -*- 2 3 // Copyright (C) 2001-2015 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 namespace std _GLIBCXX_VISIBILITY(default) 53 { 54 _GLIBCXX_BEGIN_NAMESPACE_VERSION 55 56 /** 57 * @addtogroup allocators 58 * @{ 59 */ 60 61 /// allocator<void> specialization. 62 template<> 63 class allocator<void> 64 { 65 public: 66 typedef size_t size_type; 67 typedef ptrdiff_t difference_type; 68 typedef void* pointer; 69 typedef const void* const_pointer; 70 typedef void value_type; 71 72 template<typename _Tp1> 73 struct rebind 74 { typedef allocator<_Tp1> other; }; 75 76 #if __cplusplus >= 201103L 77 // _GLIBCXX_RESOLVE_LIB_DEFECTS 78 // 2103. std::allocator propagate_on_container_move_assignment 79 typedef true_type propagate_on_container_move_assignment; 80 81 template<typename _Up, typename... _Args> 82 void 83 construct(_Up* __p, _Args&&... __args) 84 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 85 86 template<typename _Up> 87 void 88 destroy(_Up* __p) { __p->~_Up(); } 89 #endif 90 }; 91 92 /** 93 * @brief The @a standard allocator, as per [20.4]. 94 * 95 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator 96 * for further details. 97 * 98 * @tparam _Tp Type of allocated object. 99 */ 100 template<typename _Tp> 101 class allocator: public __allocator_base<_Tp> 102 { 103 public: 104 typedef size_t size_type; 105 typedef ptrdiff_t difference_type; 106 typedef _Tp* pointer; 107 typedef const _Tp* const_pointer; 108 typedef _Tp& reference; 109 typedef const _Tp& const_reference; 110 typedef _Tp value_type; 111 112 template<typename _Tp1> 113 struct rebind 114 { typedef allocator<_Tp1> other; }; 115 116 #if __cplusplus >= 201103L 117 // _GLIBCXX_RESOLVE_LIB_DEFECTS 118 // 2103. std::allocator propagate_on_container_move_assignment 119 typedef true_type propagate_on_container_move_assignment; 120 #endif 121 122 allocator() throw() { } 123 124 allocator(const allocator& __a) throw() 125 : __allocator_base<_Tp>(__a) { } 126 127 template<typename _Tp1> 128 allocator(const allocator<_Tp1>&) throw() { } 129 130 ~allocator() throw() { } 131 132 // Inherit everything else. 133 }; 134 135 template<typename _T1, typename _T2> 136 inline bool 137 operator==(const allocator<_T1>&, const allocator<_T2>&) 138 _GLIBCXX_USE_NOEXCEPT 139 { return true; } 140 141 template<typename _Tp> 142 inline bool 143 operator==(const allocator<_Tp>&, const allocator<_Tp>&) 144 _GLIBCXX_USE_NOEXCEPT 145 { return true; } 146 147 template<typename _T1, typename _T2> 148 inline bool 149 operator!=(const allocator<_T1>&, const allocator<_T2>&) 150 _GLIBCXX_USE_NOEXCEPT 151 { return false; } 152 153 template<typename _Tp> 154 inline bool 155 operator!=(const allocator<_Tp>&, const allocator<_Tp>&) 156 _GLIBCXX_USE_NOEXCEPT 157 { return false; } 158 159 /// @} group allocator 160 161 // Inhibit implicit instantiations for required instantiations, 162 // which are defined via explicit instantiations elsewhere. 163 #if _GLIBCXX_EXTERN_TEMPLATE 164 extern template class allocator<char>; 165 extern template class allocator<wchar_t>; 166 #endif 167 168 // Undefine. 169 #undef __allocator_base 170 171 // To implement Option 3 of DR 431. 172 template<typename _Alloc, bool = __is_empty(_Alloc)> 173 struct __alloc_swap 174 { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } }; 175 176 template<typename _Alloc> 177 struct __alloc_swap<_Alloc, false> 178 { 179 static void 180 _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT 181 { 182 // Precondition: swappable allocators. 183 if (__one != __two) 184 swap(__one, __two); 185 } 186 }; 187 188 // Optimize for stateless allocators. 189 template<typename _Alloc, bool = __is_empty(_Alloc)> 190 struct __alloc_neq 191 { 192 static bool 193 _S_do_it(const _Alloc&, const _Alloc&) 194 { return false; } 195 }; 196 197 template<typename _Alloc> 198 struct __alloc_neq<_Alloc, false> 199 { 200 static bool 201 _S_do_it(const _Alloc& __one, const _Alloc& __two) 202 { return __one != __two; } 203 }; 204 205 #if __cplusplus >= 201103L 206 template<typename _Tp, bool 207 = __or_<is_copy_constructible<typename _Tp::value_type>, 208 is_nothrow_move_constructible<typename _Tp::value_type>>::value> 209 struct __shrink_to_fit_aux 210 { static bool _S_do_it(_Tp&) noexcept { return false; } }; 211 212 template<typename _Tp> 213 struct __shrink_to_fit_aux<_Tp, true> 214 { 215 static bool 216 _S_do_it(_Tp& __c) noexcept 217 { 218 #if __cpp_exceptions 219 try 220 { 221 _Tp(__make_move_if_noexcept_iterator(__c.begin()), 222 __make_move_if_noexcept_iterator(__c.end()), 223 __c.get_allocator()).swap(__c); 224 return true; 225 } 226 catch(...) 227 { return false; } 228 #else 229 return false; 230 #endif 231 } 232 }; 233 #endif 234 235 _GLIBCXX_END_NAMESPACE_VERSION 236 } // namespace std 237 238 #endif 239