libstdc++
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00001 // Allocators -*- C++ -*- 00002 00003 // Copyright (C) 2001-2018 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 /* 00026 * Copyright (c) 1996-1997 00027 * Silicon Graphics Computer Systems, Inc. 00028 * 00029 * Permission to use, copy, modify, distribute and sell this software 00030 * and its documentation for any purpose is hereby granted without fee, 00031 * provided that the above copyright notice appear in all copies and 00032 * that both that copyright notice and this permission notice appear 00033 * in supporting documentation. Silicon Graphics makes no 00034 * representations about the suitability of this software for any 00035 * purpose. It is provided "as is" without express or implied warranty. 00036 */ 00037 00038 /** @file bits/allocator.h 00039 * This is an internal header file, included by other library headers. 00040 * Do not attempt to use it directly. @headername{memory} 00041 */ 00042 00043 #ifndef _ALLOCATOR_H 00044 #define _ALLOCATOR_H 1 00045 00046 #include <bits/c++allocator.h> // Define the base class to std::allocator. 00047 #include <bits/memoryfwd.h> 00048 #if __cplusplus >= 201103L 00049 #include <type_traits> 00050 #endif 00051 00052 #define __cpp_lib_incomplete_container_elements 201505 00053 #if __cplusplus >= 201103L 00054 # define __cpp_lib_allocator_is_always_equal 201411 00055 #endif 00056 00057 namespace std _GLIBCXX_VISIBILITY(default) 00058 { 00059 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00060 00061 /** 00062 * @addtogroup allocators 00063 * @{ 00064 */ 00065 00066 /// allocator<void> specialization. 00067 template<> 00068 class allocator<void> 00069 { 00070 public: 00071 typedef size_t size_type; 00072 typedef ptrdiff_t difference_type; 00073 typedef void* pointer; 00074 typedef const void* const_pointer; 00075 typedef void value_type; 00076 00077 template<typename _Tp1> 00078 struct rebind 00079 { typedef allocator<_Tp1> other; }; 00080 00081 #if __cplusplus >= 201103L 00082 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00083 // 2103. std::allocator propagate_on_container_move_assignment 00084 typedef true_type propagate_on_container_move_assignment; 00085 00086 typedef true_type is_always_equal; 00087 00088 template<typename _Up, typename... _Args> 00089 void 00090 construct(_Up* __p, _Args&&... __args) 00091 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 00092 00093 template<typename _Up> 00094 void 00095 destroy(_Up* __p) { __p->~_Up(); } 00096 #endif 00097 }; 00098 00099 /** 00100 * @brief The @a standard allocator, as per [20.4]. 00101 * 00102 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/memory.html#std.util.memory.allocator 00103 * for further details. 00104 * 00105 * @tparam _Tp Type of allocated object. 00106 */ 00107 template<typename _Tp> 00108 class allocator : public __allocator_base<_Tp> 00109 { 00110 public: 00111 typedef size_t size_type; 00112 typedef ptrdiff_t difference_type; 00113 typedef _Tp* pointer; 00114 typedef const _Tp* const_pointer; 00115 typedef _Tp& reference; 00116 typedef const _Tp& const_reference; 00117 typedef _Tp value_type; 00118 00119 template<typename _Tp1> 00120 struct rebind 00121 { typedef allocator<_Tp1> other; }; 00122 00123 #if __cplusplus >= 201103L 00124 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00125 // 2103. std::allocator propagate_on_container_move_assignment 00126 typedef true_type propagate_on_container_move_assignment; 00127 00128 typedef true_type is_always_equal; 00129 #endif 00130 00131 allocator() throw() { } 00132 00133 allocator(const allocator& __a) throw() 00134 : __allocator_base<_Tp>(__a) { } 00135 00136 template<typename _Tp1> 00137 allocator(const allocator<_Tp1>&) throw() { } 00138 00139 ~allocator() throw() { } 00140 00141 // Inherit everything else. 00142 }; 00143 00144 template<typename _T1, typename _T2> 00145 inline bool 00146 operator==(const allocator<_T1>&, const allocator<_T2>&) 00147 _GLIBCXX_USE_NOEXCEPT 00148 { return true; } 00149 00150 template<typename _Tp> 00151 inline bool 00152 operator==(const allocator<_Tp>&, const allocator<_Tp>&) 00153 _GLIBCXX_USE_NOEXCEPT 00154 { return true; } 00155 00156 template<typename _T1, typename _T2> 00157 inline bool 00158 operator!=(const allocator<_T1>&, const allocator<_T2>&) 00159 _GLIBCXX_USE_NOEXCEPT 00160 { return false; } 00161 00162 template<typename _Tp> 00163 inline bool 00164 operator!=(const allocator<_Tp>&, const allocator<_Tp>&) 00165 _GLIBCXX_USE_NOEXCEPT 00166 { return false; } 00167 00168 // Invalid allocator<cv T> partial specializations. 00169 // allocator_traits::rebind_alloc can be used to form a valid allocator type. 00170 template<typename _Tp> 00171 class allocator<const _Tp> 00172 { 00173 public: 00174 typedef _Tp value_type; 00175 template<typename _Up> allocator(const allocator<_Up>&) { } 00176 }; 00177 00178 template<typename _Tp> 00179 class allocator<volatile _Tp> 00180 { 00181 public: 00182 typedef _Tp value_type; 00183 template<typename _Up> allocator(const allocator<_Up>&) { } 00184 }; 00185 00186 template<typename _Tp> 00187 class allocator<const volatile _Tp> 00188 { 00189 public: 00190 typedef _Tp value_type; 00191 template<typename _Up> allocator(const allocator<_Up>&) { } 00192 }; 00193 00194 /// @} group allocator 00195 00196 // Inhibit implicit instantiations for required instantiations, 00197 // which are defined via explicit instantiations elsewhere. 00198 #if _GLIBCXX_EXTERN_TEMPLATE 00199 extern template class allocator<char>; 00200 extern template class allocator<wchar_t>; 00201 #endif 00202 00203 // Undefine. 00204 #undef __allocator_base 00205 00206 // To implement Option 3 of DR 431. 00207 template<typename _Alloc, bool = __is_empty(_Alloc)> 00208 struct __alloc_swap 00209 { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } }; 00210 00211 template<typename _Alloc> 00212 struct __alloc_swap<_Alloc, false> 00213 { 00214 static void 00215 _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT 00216 { 00217 // Precondition: swappable allocators. 00218 if (__one != __two) 00219 swap(__one, __two); 00220 } 00221 }; 00222 00223 // Optimize for stateless allocators. 00224 template<typename _Alloc, bool = __is_empty(_Alloc)> 00225 struct __alloc_neq 00226 { 00227 static bool 00228 _S_do_it(const _Alloc&, const _Alloc&) 00229 { return false; } 00230 }; 00231 00232 template<typename _Alloc> 00233 struct __alloc_neq<_Alloc, false> 00234 { 00235 static bool 00236 _S_do_it(const _Alloc& __one, const _Alloc& __two) 00237 { return __one != __two; } 00238 }; 00239 00240 #if __cplusplus >= 201103L 00241 template<typename _Tp, bool 00242 = __or_<is_copy_constructible<typename _Tp::value_type>, 00243 is_nothrow_move_constructible<typename _Tp::value_type>>::value> 00244 struct __shrink_to_fit_aux 00245 { static bool _S_do_it(_Tp&) noexcept { return false; } }; 00246 00247 template<typename _Tp> 00248 struct __shrink_to_fit_aux<_Tp, true> 00249 { 00250 static bool 00251 _S_do_it(_Tp& __c) noexcept 00252 { 00253 #if __cpp_exceptions 00254 try 00255 { 00256 _Tp(__make_move_if_noexcept_iterator(__c.begin()), 00257 __make_move_if_noexcept_iterator(__c.end()), 00258 __c.get_allocator()).swap(__c); 00259 return true; 00260 } 00261 catch(...) 00262 { return false; } 00263 #else 00264 return false; 00265 #endif 00266 } 00267 }; 00268 #endif 00269 00270 _GLIBCXX_END_NAMESPACE_VERSION 00271 } // namespace std 00272 00273 #endif