1 // Node handles for containers -*- C++ -*- 2 3 // Copyright (C) 2016-2017 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 /** @file bits/node_handle.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. 28 * @headername{map,set,unordered_map,unordered_set} 29 */ 30 31 #ifndef _NODE_HANDLE 32 #define _NODE_HANDLE 1 33 34 #pragma GCC system_header 35 36 #if __cplusplus > 201402L 37 # define __cpp_lib_node_extract 201606 38 39 #include <optional> 40 #include <bits/alloc_traits.h> 41 #include <bits/ptr_traits.h> 42 43 namespace std _GLIBCXX_VISIBILITY(default) 44 { 45 _GLIBCXX_BEGIN_NAMESPACE_VERSION 46 47 /// Base class for node handle types of maps and sets. 48 template<typename _Val, typename _NodeAlloc> 49 class _Node_handle_common 50 { 51 using _AllocTraits = allocator_traits<_NodeAlloc>; 52 53 public: 54 using allocator_type = __alloc_rebind<_NodeAlloc, _Val>; 55 56 allocator_type 57 get_allocator() const noexcept 58 { 59 __glibcxx_assert(!this->empty()); 60 return allocator_type(*_M_alloc); 61 } 62 63 explicit operator bool() const noexcept { return _M_ptr != nullptr; } 64 65 bool empty() const noexcept { return _M_ptr == nullptr; } 66 67 protected: 68 constexpr _Node_handle_common() noexcept : _M_ptr(), _M_alloc() {} 69 70 ~_Node_handle_common() { _M_destroy(); } 71 72 _Node_handle_common(_Node_handle_common&& __nh) noexcept 73 : _M_ptr(__nh._M_ptr), _M_alloc(std::move(__nh._M_alloc)) 74 { 75 __nh._M_ptr = nullptr; 76 __nh._M_alloc = nullopt; 77 } 78 79 _Node_handle_common& 80 operator=(_Node_handle_common&& __nh) noexcept 81 { 82 _M_destroy(); 83 _M_ptr = __nh._M_ptr; 84 if constexpr (is_move_assignable_v<_NodeAlloc>) 85 { 86 if (_AllocTraits::propagate_on_container_move_assignment::value 87 || !this->_M_alloc) 88 this->_M_alloc = std::move(__nh._M_alloc); 89 else 90 __glibcxx_assert(this->_M_alloc == __nh._M_alloc); 91 } 92 else 93 __glibcxx_assert(_M_alloc); 94 __nh._M_ptr = nullptr; 95 __nh._M_alloc = nullopt; 96 return *this; 97 } 98 99 _Node_handle_common(typename _AllocTraits::pointer __ptr, 100 const _NodeAlloc& __alloc) 101 : _M_ptr(__ptr), _M_alloc(__alloc) { } 102 103 void 104 _M_swap(_Node_handle_common& __nh) noexcept 105 { 106 using std::swap; 107 swap(_M_ptr, __nh._M_ptr); 108 if (_AllocTraits::propagate_on_container_swap::value 109 || !_M_alloc || !__nh._M_alloc) 110 _M_alloc.swap(__nh._M_alloc); 111 else 112 __glibcxx_assert(_M_alloc == __nh._M_alloc); 113 } 114 115 private: 116 void 117 _M_destroy() noexcept 118 { 119 if (_M_ptr != nullptr) 120 { 121 allocator_type __alloc(*_M_alloc); 122 allocator_traits<allocator_type>::destroy(__alloc, 123 _M_ptr->_M_valptr()); 124 _AllocTraits::deallocate(*_M_alloc, _M_ptr, 1); 125 } 126 } 127 128 protected: 129 typename _AllocTraits::pointer _M_ptr; 130 private: 131 optional<_NodeAlloc> _M_alloc; 132 133 template<typename _Key2, typename _Value2, typename _KeyOfValue, 134 typename _Compare, typename _ValueAlloc> 135 friend class _Rb_tree; 136 }; 137 138 /// Node handle type for maps. 139 template<typename _Key, typename _Value, typename _NodeAlloc> 140 class _Node_handle : public _Node_handle_common<_Value, _NodeAlloc> 141 { 142 public: 143 constexpr _Node_handle() noexcept = default; 144 ~_Node_handle() = default; 145 _Node_handle(_Node_handle&&) noexcept = default; 146 147 _Node_handle& 148 operator=(_Node_handle&&) noexcept = default; 149 150 using key_type = _Key; 151 using mapped_type = typename _Value::second_type; 152 153 key_type& 154 key() const noexcept 155 { 156 __glibcxx_assert(!this->empty()); 157 return *_M_pkey; 158 } 159 160 mapped_type& 161 mapped() const noexcept 162 { 163 __glibcxx_assert(!this->empty()); 164 return *_M_pmapped; 165 } 166 167 void 168 swap(_Node_handle& __nh) noexcept 169 { 170 this->_M_swap(__nh); 171 using std::swap; 172 swap(_M_pkey, __nh._M_pkey); 173 swap(_M_pmapped, __nh._M_pmapped); 174 } 175 176 friend void 177 swap(_Node_handle& __x, _Node_handle& __y) 178 noexcept(noexcept(__x.swap(__y))) 179 { __x.swap(__y); } 180 181 private: 182 using _AllocTraits = allocator_traits<_NodeAlloc>; 183 184 _Node_handle(typename _AllocTraits::pointer __ptr, 185 const _NodeAlloc& __alloc) 186 : _Node_handle_common<_Value, _NodeAlloc>(__ptr, __alloc) 187 { 188 if (__ptr) 189 { 190 auto& __key = const_cast<_Key&>(__ptr->_M_valptr()->first); 191 _M_pkey = _S_pointer_to(__key); 192 _M_pmapped = _S_pointer_to(__ptr->_M_valptr()->second); 193 } 194 else 195 { 196 _M_pkey = nullptr; 197 _M_pmapped = nullptr; 198 } 199 } 200 201 template<typename _Tp> 202 using __pointer 203 = __ptr_rebind<typename _AllocTraits::pointer, 204 remove_reference_t<_Tp>>; 205 206 __pointer<_Key> _M_pkey = nullptr; 207 __pointer<typename _Value::second_type> _M_pmapped = nullptr; 208 209 template<typename _Tp> 210 __pointer<_Tp> 211 _S_pointer_to(_Tp& __obj) 212 { return pointer_traits<__pointer<_Tp>>::pointer_to(__obj); } 213 214 const key_type& 215 _M_key() const noexcept { return key(); } 216 217 template<typename _Key2, typename _Value2, typename _KeyOfValue, 218 typename _Compare, typename _ValueAlloc> 219 friend class _Rb_tree; 220 221 template<typename _Key2, typename _Value2, typename _ValueAlloc, 222 typename _ExtractKey, typename _Equal, 223 typename _H1, typename _H2, typename _Hash, 224 typename _RehashPolicy, typename _Traits> 225 friend class _Hashtable; 226 }; 227 228 /// Node handle type for sets. 229 template<typename _Value, typename _NodeAlloc> 230 class _Node_handle<_Value, _Value, _NodeAlloc> 231 : public _Node_handle_common<_Value, _NodeAlloc> 232 { 233 public: 234 constexpr _Node_handle() noexcept = default; 235 ~_Node_handle() = default; 236 _Node_handle(_Node_handle&&) noexcept = default; 237 238 _Node_handle& 239 operator=(_Node_handle&&) noexcept = default; 240 241 using value_type = _Value; 242 243 value_type& 244 value() const noexcept 245 { 246 __glibcxx_assert(!this->empty()); 247 return *this->_M_ptr->_M_valptr(); 248 } 249 250 void 251 swap(_Node_handle& __nh) noexcept 252 { this->_M_swap(__nh); } 253 254 friend void 255 swap(_Node_handle& __x, _Node_handle& __y) 256 noexcept(noexcept(__x.swap(__y))) 257 { __x.swap(__y); } 258 259 private: 260 using _AllocTraits = allocator_traits<_NodeAlloc>; 261 262 _Node_handle(typename _AllocTraits::pointer __ptr, 263 const _NodeAlloc& __alloc) 264 : _Node_handle_common<_Value, _NodeAlloc>(__ptr, __alloc) { } 265 266 const value_type& 267 _M_key() const noexcept { return value(); } 268 269 template<typename _Key, typename _Val, typename _KeyOfValue, 270 typename _Compare, typename _Alloc> 271 friend class _Rb_tree; 272 273 template<typename _Key2, typename _Value2, typename _ValueAlloc, 274 typename _ExtractKey, typename _Equal, 275 typename _H1, typename _H2, typename _Hash, 276 typename _RehashPolicy, typename _Traits> 277 friend class _Hashtable; 278 }; 279 280 /// Return type of insert(node_handle&&) on unique maps/sets. 281 template<typename _Iterator, typename _NodeHandle> 282 struct _Node_insert_return 283 { 284 _Iterator position = _Iterator(); 285 bool inserted = false; 286 _NodeHandle node; 287 }; 288 289 _GLIBCXX_END_NAMESPACE_VERSION 290 } // namespace std 291 292 #endif // C++17 293 #endif 294