1 // Stack implementation -*- C++ -*- 2 3 // Copyright (C) 2001-2019 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 * 27 * Copyright (c) 1994 28 * Hewlett-Packard Company 29 * 30 * Permission to use, copy, modify, distribute and sell this software 31 * and its documentation for any purpose is hereby granted without fee, 32 * provided that the above copyright notice appear in all copies and 33 * that both that copyright notice and this permission notice appear 34 * in supporting documentation. Hewlett-Packard Company makes no 35 * representations about the suitability of this software for any 36 * purpose. It is provided "as is" without express or implied warranty. 37 * 38 * 39 * Copyright (c) 1996,1997 40 * Silicon Graphics Computer Systems, Inc. 41 * 42 * Permission to use, copy, modify, distribute and sell this software 43 * and its documentation for any purpose is hereby granted without fee, 44 * provided that the above copyright notice appear in all copies and 45 * that both that copyright notice and this permission notice appear 46 * in supporting documentation. Silicon Graphics makes no 47 * representations about the suitability of this software for any 48 * purpose. It is provided "as is" without express or implied warranty. 49 */ 50 51 /** @file bits/stl_stack.h 52 * This is an internal header file, included by other library headers. 53 * Do not attempt to use it directly. @headername{stack} 54 */ 55 56 #ifndef _STL_STACK_H 57 #define _STL_STACK_H 1 58 59 #include <bits/concept_check.h> 60 #include <debug/debug.h> 61 #if __cplusplus >= 201103L 62 # include <bits/uses_allocator.h> 63 #endif 64 65 namespace std _GLIBCXX_VISIBILITY(default) 66 { 67 _GLIBCXX_BEGIN_NAMESPACE_VERSION 68 69 /** 70 * @brief A standard container giving FILO behavior. 71 * 72 * @ingroup sequences 73 * 74 * @tparam _Tp Type of element. 75 * @tparam _Sequence Type of underlying sequence, defaults to deque<_Tp>. 76 * 77 * Meets many of the requirements of a 78 * <a href="tables.html#65">container</a>, 79 * but does not define anything to do with iterators. Very few of the 80 * other standard container interfaces are defined. 81 * 82 * This is not a true container, but an @e adaptor. It holds 83 * another container, and provides a wrapper interface to that 84 * container. The wrapper is what enforces strict 85 * first-in-last-out %stack behavior. 86 * 87 * The second template parameter defines the type of the underlying 88 * sequence/container. It defaults to std::deque, but it can be 89 * any type that supports @c back, @c push_back, and @c pop_back, 90 * such as std::list, std::vector, or an appropriate user-defined 91 * type. 92 * 93 * Members not found in @a normal containers are @c container_type, 94 * which is a typedef for the second Sequence parameter, and @c 95 * push, @c pop, and @c top, which are standard %stack/FILO 96 * operations. 97 */ 98 template<typename _Tp, typename _Sequence = deque<_Tp> > 99 class stack 100 { 101 #ifdef _GLIBCXX_CONCEPT_CHECKS 102 // concept requirements 103 typedef typename _Sequence::value_type _Sequence_value_type; 104 # if __cplusplus < 201103L 105 __glibcxx_class_requires(_Tp, _SGIAssignableConcept) 106 __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept) 107 # endif 108 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept) 109 #endif 110 111 template<typename _Tp1, typename _Seq1> 112 friend bool 113 operator==(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&); 114 115 template<typename _Tp1, typename _Seq1> 116 friend bool 117 operator<(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&); 118 119 #if __cplusplus >= 201103L 120 template<typename _Alloc> 121 using _Uses = typename 122 enable_if<uses_allocator<_Sequence, _Alloc>::value>::type; 123 124 #if __cplusplus >= 201703L 125 // _GLIBCXX_RESOLVE_LIB_DEFECTS 126 // 2566. Requirements on the first template parameter of container 127 // adaptors 128 static_assert(is_same<_Tp, typename _Sequence::value_type>::value, 129 "value_type must be the same as the underlying container"); 130 #endif // C++17 131 #endif // C++11 132 133 public: 134 typedef typename _Sequence::value_type value_type; 135 typedef typename _Sequence::reference reference; 136 typedef typename _Sequence::const_reference const_reference; 137 typedef typename _Sequence::size_type size_type; 138 typedef _Sequence container_type; 139 140 protected: 141 // See queue::c for notes on this name. 142 _Sequence c; 143 144 public: 145 // XXX removed old def ctor, added def arg to this one to match 14882 146 /** 147 * @brief Default constructor creates no elements. 148 */ 149 #if __cplusplus < 201103L 150 explicit 151 stack(const _Sequence& __c = _Sequence()) 152 : c(__c) { } 153 #else 154 template<typename _Seq = _Sequence, typename _Requires = typename 155 enable_if<is_default_constructible<_Seq>::value>::type> 156 stack() 157 : c() { } 158 159 explicit 160 stack(const _Sequence& __c) 161 : c(__c) { } 162 163 explicit 164 stack(_Sequence&& __c) 165 : c(std::move(__c)) { } 166 167 template<typename _Alloc, typename _Requires = _Uses<_Alloc>> 168 explicit 169 stack(const _Alloc& __a) 170 : c(__a) { } 171 172 template<typename _Alloc, typename _Requires = _Uses<_Alloc>> 173 stack(const _Sequence& __c, const _Alloc& __a) 174 : c(__c, __a) { } 175 176 template<typename _Alloc, typename _Requires = _Uses<_Alloc>> 177 stack(_Sequence&& __c, const _Alloc& __a) 178 : c(std::move(__c), __a) { } 179 180 template<typename _Alloc, typename _Requires = _Uses<_Alloc>> 181 stack(const stack& __q, const _Alloc& __a) 182 : c(__q.c, __a) { } 183 184 template<typename _Alloc, typename _Requires = _Uses<_Alloc>> 185 stack(stack&& __q, const _Alloc& __a) 186 : c(std::move(__q.c), __a) { } 187 #endif 188 189 /** 190 * Returns true if the %stack is empty. 191 */ 192 _GLIBCXX_NODISCARD bool 193 empty() const 194 { return c.empty(); } 195 196 /** Returns the number of elements in the %stack. */ 197 size_type 198 size() const 199 { return c.size(); } 200 201 /** 202 * Returns a read/write reference to the data at the first 203 * element of the %stack. 204 */ 205 reference 206 top() 207 { 208 __glibcxx_requires_nonempty(); 209 return c.back(); 210 } 211 212 /** 213 * Returns a read-only (constant) reference to the data at the first 214 * element of the %stack. 215 */ 216 const_reference 217 top() const 218 { 219 __glibcxx_requires_nonempty(); 220 return c.back(); 221 } 222 223 /** 224 * @brief Add data to the top of the %stack. 225 * @param __x Data to be added. 226 * 227 * This is a typical %stack operation. The function creates an 228 * element at the top of the %stack and assigns the given data 229 * to it. The time complexity of the operation depends on the 230 * underlying sequence. 231 */ 232 void 233 push(const value_type& __x) 234 { c.push_back(__x); } 235 236 #if __cplusplus >= 201103L 237 void 238 push(value_type&& __x) 239 { c.push_back(std::move(__x)); } 240 241 #if __cplusplus > 201402L 242 template<typename... _Args> 243 decltype(auto) 244 emplace(_Args&&... __args) 245 { return c.emplace_back(std::forward<_Args>(__args)...); } 246 #else 247 template<typename... _Args> 248 void 249 emplace(_Args&&... __args) 250 { c.emplace_back(std::forward<_Args>(__args)...); } 251 #endif 252 #endif 253 254 /** 255 * @brief Removes first element. 256 * 257 * This is a typical %stack operation. It shrinks the %stack 258 * by one. The time complexity of the operation depends on the 259 * underlying sequence. 260 * 261 * Note that no data is returned, and if the first element's 262 * data is needed, it should be retrieved before pop() is 263 * called. 264 */ 265 void 266 pop() 267 { 268 __glibcxx_requires_nonempty(); 269 c.pop_back(); 270 } 271 272 #if __cplusplus >= 201103L 273 void 274 swap(stack& __s) 275 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 276 noexcept(__is_nothrow_swappable<_Sequence>::value) 277 #else 278 noexcept(__is_nothrow_swappable<_Tp>::value) 279 #endif 280 { 281 using std::swap; 282 swap(c, __s.c); 283 } 284 #endif // __cplusplus >= 201103L 285 }; 286 287 #if __cpp_deduction_guides >= 201606 288 template<typename _Container, 289 typename = _RequireNotAllocator<_Container>> 290 stack(_Container) -> stack<typename _Container::value_type, _Container>; 291 292 template<typename _Container, typename _Allocator, 293 typename = _RequireNotAllocator<_Container>, 294 typename = _RequireAllocator<_Allocator>> 295 stack(_Container, _Allocator) 296 -> stack<typename _Container::value_type, _Container>; 297 #endif 298 299 /** 300 * @brief Stack equality comparison. 301 * @param __x A %stack. 302 * @param __y A %stack of the same type as @a __x. 303 * @return True iff the size and elements of the stacks are equal. 304 * 305 * This is an equivalence relation. Complexity and semantics 306 * depend on the underlying sequence type, but the expected rules 307 * are: this relation is linear in the size of the sequences, and 308 * stacks are considered equivalent if their sequences compare 309 * equal. 310 */ 311 template<typename _Tp, typename _Seq> 312 inline bool 313 operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) 314 { return __x.c == __y.c; } 315 316 /** 317 * @brief Stack ordering relation. 318 * @param __x A %stack. 319 * @param __y A %stack of the same type as @a x. 320 * @return True iff @a x is lexicographically less than @a __y. 321 * 322 * This is an total ordering relation. Complexity and semantics 323 * depend on the underlying sequence type, but the expected rules 324 * are: this relation is linear in the size of the sequences, the 325 * elements must be comparable with @c <, and 326 * std::lexicographical_compare() is usually used to make the 327 * determination. 328 */ 329 template<typename _Tp, typename _Seq> 330 inline bool 331 operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) 332 { return __x.c < __y.c; } 333 334 /// Based on operator== 335 template<typename _Tp, typename _Seq> 336 inline bool 337 operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) 338 { return !(__x == __y); } 339 340 /// Based on operator< 341 template<typename _Tp, typename _Seq> 342 inline bool 343 operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) 344 { return __y < __x; } 345 346 /// Based on operator< 347 template<typename _Tp, typename _Seq> 348 inline bool 349 operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) 350 { return !(__y < __x); } 351 352 /// Based on operator< 353 template<typename _Tp, typename _Seq> 354 inline bool 355 operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) 356 { return !(__x < __y); } 357 358 #if __cplusplus >= 201103L 359 template<typename _Tp, typename _Seq> 360 inline 361 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 362 // Constrained free swap overload, see p0185r1 363 typename enable_if<__is_swappable<_Seq>::value>::type 364 #else 365 void 366 #endif 367 swap(stack<_Tp, _Seq>& __x, stack<_Tp, _Seq>& __y) 368 noexcept(noexcept(__x.swap(__y))) 369 { __x.swap(__y); } 370 371 template<typename _Tp, typename _Seq, typename _Alloc> 372 struct uses_allocator<stack<_Tp, _Seq>, _Alloc> 373 : public uses_allocator<_Seq, _Alloc>::type { }; 374 #endif // __cplusplus >= 201103L 375 376 _GLIBCXX_END_NAMESPACE_VERSION 377 } // namespace 378 379 #endif /* _STL_STACK_H */ 380