libstdc++
debug/forward_list
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1 // <forward_list> -*- C++ -*-
2 
3 // Copyright (C) 2010-2021 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 debug/forward_list
26  * This file is a GNU debug extension to the Standard C++ Library.
27  */
28 
29 #ifndef _GLIBCXX_DEBUG_FORWARD_LIST
30 #define _GLIBCXX_DEBUG_FORWARD_LIST 1
31 
32 #pragma GCC system_header
33 
34 #include <bits/c++config.h>
35 namespace std _GLIBCXX_VISIBILITY(default) { namespace __debug {
36  template<typename _Tp, typename _Allocator> class forward_list;
37 } } // namespace std::__debug
38 
39 #include <forward_list>
40 #include <debug/safe_sequence.h>
41 #include <debug/safe_container.h>
42 #include <debug/safe_iterator.h>
43 
44 // Special validity check for forward_list ranges.
45 #define __glibcxx_check_valid_fl_range(_First,_Last,_Dist) \
46 _GLIBCXX_DEBUG_VERIFY(_First._M_valid_range(_Last, _Dist, false), \
47  _M_message(__gnu_debug::__msg_valid_range) \
48  ._M_iterator(_First, #_First) \
49  ._M_iterator(_Last, #_Last))
50 
51 namespace __gnu_debug
52 {
53  /// Special iterators swap and invalidation for forward_list because of the
54  /// before_begin iterator.
55  template<typename _SafeSequence>
56  class _Safe_forward_list
57  : public _Safe_sequence<_SafeSequence>
58  {
59  _SafeSequence&
60  _M_this() noexcept
61  { return *static_cast<_SafeSequence*>(this); }
62 
63  static void
64  _M_swap_aux(_Safe_sequence_base& __lhs,
65  _Safe_iterator_base*& __lhs_iterators,
66  _Safe_sequence_base& __rhs,
67  _Safe_iterator_base*& __rhs_iterators);
68 
69  void _M_swap_single(_Safe_sequence_base&) noexcept;
70 
71  protected:
72  void
73  _M_invalidate_all()
74  {
75  using _Base_const_iterator = __decltype(_M_this()._M_base().cend());
76  this->_M_invalidate_if([this](_Base_const_iterator __it)
77  {
78  return __it != _M_this()._M_base().cbefore_begin()
79  && __it != _M_this()._M_base().cend(); });
80  }
81 
82  void _M_swap(_Safe_sequence_base&) noexcept;
83  };
84 
85  template<typename _SafeSequence>
86  void
87  _Safe_forward_list<_SafeSequence>::
88  _M_swap_aux(_Safe_sequence_base& __lhs,
89  _Safe_iterator_base*& __lhs_iterators,
90  _Safe_sequence_base& __rhs,
91  _Safe_iterator_base*& __rhs_iterators)
92  {
93  using const_iterator = typename _SafeSequence::const_iterator;
94  _Safe_iterator_base* __bbegin_its = 0;
95  _Safe_iterator_base* __last_bbegin = 0;
96  _SafeSequence& __rseq = static_cast<_SafeSequence&>(__rhs);
97 
98  for (_Safe_iterator_base* __iter = __lhs_iterators; __iter;)
99  {
100  // Even iterator is cast to const_iterator, not a problem.
101  _Safe_iterator_base* __victim_base = __iter;
102  const_iterator* __victim =
103  static_cast<const_iterator*>(__victim_base);
104  __iter = __iter->_M_next;
105  if (__victim->base() == __rseq._M_base().cbefore_begin())
106  {
107  __victim->_M_unlink();
108  if (__lhs_iterators == __victim_base)
109  __lhs_iterators = __victim_base->_M_next;
110  if (__bbegin_its)
111  {
112  __victim_base->_M_next = __bbegin_its;
113  __bbegin_its->_M_prior = __victim_base;
114  }
115  else
116  __last_bbegin = __victim_base;
117  __bbegin_its = __victim_base;
118  }
119  else
120  __victim_base->_M_sequence = std::__addressof(__lhs);
121  }
122 
123  if (__bbegin_its)
124  {
125  if (__rhs_iterators)
126  {
127  __rhs_iterators->_M_prior = __last_bbegin;
128  __last_bbegin->_M_next = __rhs_iterators;
129  }
130  __rhs_iterators = __bbegin_its;
131  }
132  }
133 
134  template<typename _SafeSequence>
135  void
136  _Safe_forward_list<_SafeSequence>::
137  _M_swap_single(_Safe_sequence_base& __other) noexcept
138  {
139  std::swap(_M_this()._M_iterators, __other._M_iterators);
140  std::swap(_M_this()._M_const_iterators, __other._M_const_iterators);
141  // Useless, always 1 on forward_list
142  //std::swap(_M_this()_M_version, __other._M_version);
143  _Safe_iterator_base* __this_its = _M_this()._M_iterators;
144  _M_swap_aux(__other, __other._M_iterators,
145  _M_this(), _M_this()._M_iterators);
146  _Safe_iterator_base* __this_const_its = _M_this()._M_const_iterators;
147  _M_swap_aux(__other, __other._M_const_iterators,
148  _M_this(), _M_this()._M_const_iterators);
149  _M_swap_aux(_M_this(), __this_its,
150  __other, __other._M_iterators);
151  _M_swap_aux(_M_this(), __this_const_its,
152  __other, __other._M_const_iterators);
153  }
154 
155  /* Special forward_list _M_swap version that does not swap the
156  * before-begin ownership.*/
157  template<typename _SafeSequence>
158  void
159  _Safe_forward_list<_SafeSequence>::
160  _M_swap(_Safe_sequence_base& __other) noexcept
161  {
162  // We need to lock both sequences to swap
163  using namespace __gnu_cxx;
164  __mutex *__this_mutex = &_M_this()._M_get_mutex();
165  __mutex *__other_mutex =
166  &static_cast<_SafeSequence&>(__other)._M_get_mutex();
167  if (__this_mutex == __other_mutex)
168  {
169  __scoped_lock __lock(*__this_mutex);
170  _M_swap_single(__other);
171  }
172  else
173  {
174  __scoped_lock __l1(__this_mutex < __other_mutex
175  ? *__this_mutex : *__other_mutex);
176  __scoped_lock __l2(__this_mutex < __other_mutex
177  ? *__other_mutex : *__this_mutex);
178  _M_swap_single(__other);
179  }
180  }
181 }
182 
183 namespace std _GLIBCXX_VISIBILITY(default)
184 {
185 namespace __debug
186 {
187  /// Class std::forward_list with safety/checking/debug instrumentation.
188  template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
189  class forward_list
190  : public __gnu_debug::_Safe_container<
191  forward_list<_Tp, _Alloc>, _Alloc, __gnu_debug::_Safe_forward_list>,
192  public _GLIBCXX_STD_C::forward_list<_Tp, _Alloc>
193  {
194  typedef _GLIBCXX_STD_C::forward_list<_Tp, _Alloc> _Base;
195  typedef __gnu_debug::_Safe_container<
196  forward_list, _Alloc, __gnu_debug::_Safe_forward_list> _Safe;
197 
198  typedef typename _Base::iterator _Base_iterator;
199  typedef typename _Base::const_iterator _Base_const_iterator;
200 
201  template<typename _ItT, typename _SeqT, typename _CatT>
202  friend class ::__gnu_debug::_Safe_iterator;
203 
204  // Reference wrapper for base class. See PR libstdc++/90102.
205  struct _Base_ref
206  {
207  _Base_ref(const _Base& __r) : _M_ref(__r) { }
208 
209  const _Base& _M_ref;
210  };
211 
212  public:
213  typedef typename _Base::reference reference;
214  typedef typename _Base::const_reference const_reference;
215 
216  typedef __gnu_debug::_Safe_iterator<
217  _Base_iterator, forward_list> iterator;
218  typedef __gnu_debug::_Safe_iterator<
219  _Base_const_iterator, forward_list> const_iterator;
220 
221  typedef typename _Base::size_type size_type;
222  typedef typename _Base::difference_type difference_type;
223 
224  typedef _Tp value_type;
225  typedef typename _Base::allocator_type allocator_type;
226  typedef typename _Base::pointer pointer;
227  typedef typename _Base::const_pointer const_pointer;
228 
229  // 23.2.3.1 construct/copy/destroy:
230 
231  forward_list() = default;
232 
233  explicit
234  forward_list(const allocator_type& __al) noexcept
235  : _Base(__al) { }
236 
237  forward_list(const forward_list& __list, const allocator_type& __al)
238  : _Base(__list, __al)
239  { }
240 
241  forward_list(forward_list&& __list, const allocator_type& __al)
242  : _Safe(std::move(__list._M_safe()), __al),
243  _Base(std::move(__list._M_base()), __al)
244  { }
245 
246  explicit
247  forward_list(size_type __n, const allocator_type& __al = allocator_type())
248  : _Base(__n, __al)
249  { }
250 
251  forward_list(size_type __n, const _Tp& __value,
252  const allocator_type& __al = allocator_type())
253  : _Base(__n, __value, __al)
254  { }
255 
256  template<typename _InputIterator,
257  typename = std::_RequireInputIter<_InputIterator>>
258  forward_list(_InputIterator __first, _InputIterator __last,
259  const allocator_type& __al = allocator_type())
260  : _Base(__gnu_debug::__base(
261  __glibcxx_check_valid_constructor_range(__first, __last)),
262  __gnu_debug::__base(__last), __al)
263  { }
264 
265  forward_list(const forward_list&) = default;
266 
267  forward_list(forward_list&&) = default;
268 
269  forward_list(std::initializer_list<_Tp> __il,
270  const allocator_type& __al = allocator_type())
271  : _Base(__il, __al)
272  { }
273 
274  ~forward_list() = default;
275 
276  forward_list(_Base_ref __x) : _Base(__x._M_ref) { }
277 
278  forward_list&
279  operator=(const forward_list&) = default;
280 
281  forward_list&
282  operator=(forward_list&&) = default;
283 
284  forward_list&
285  operator=(std::initializer_list<_Tp> __il)
286  {
287  _M_base() = __il;
288  this->_M_invalidate_all();
289  return *this;
290  }
291 
292  template<typename _InputIterator,
293  typename = std::_RequireInputIter<_InputIterator>>
294  void
295  assign(_InputIterator __first, _InputIterator __last)
296  {
297  typename __gnu_debug::_Distance_traits<_InputIterator>::__type __dist;
298  __glibcxx_check_valid_range2(__first, __last, __dist);
299 
300  if (__dist.second >= __gnu_debug::__dp_sign)
301  _Base::assign(__gnu_debug::__unsafe(__first),
302  __gnu_debug::__unsafe(__last));
303  else
304  _Base::assign(__first, __last);
305 
306  this->_M_invalidate_all();
307  }
308 
309  void
310  assign(size_type __n, const _Tp& __val)
311  {
312  _Base::assign(__n, __val);
313  this->_M_invalidate_all();
314  }
315 
316  void
317  assign(std::initializer_list<_Tp> __il)
318  {
319  _Base::assign(__il);
320  this->_M_invalidate_all();
321  }
322 
323  using _Base::get_allocator;
324 
325  // iterators:
326 
327  iterator
328  before_begin() noexcept
329  { return { _Base::before_begin(), this }; }
330 
331  const_iterator
332  before_begin() const noexcept
333  { return { _Base::before_begin(), this }; }
334 
335  iterator
336  begin() noexcept
337  { return { _Base::begin(), this }; }
338 
339  const_iterator
340  begin() const noexcept
341  { return { _Base::begin(), this }; }
342 
343  iterator
344  end() noexcept
345  { return { _Base::end(), this }; }
346 
347  const_iterator
348  end() const noexcept
349  { return { _Base::end(), this }; }
350 
351  const_iterator
352  cbegin() const noexcept
353  { return { _Base::cbegin(), this }; }
354 
355  const_iterator
356  cbefore_begin() const noexcept
357  { return { _Base::cbefore_begin(), this }; }
358 
359  const_iterator
360  cend() const noexcept
361  { return { _Base::cend(), this }; }
362 
363  using _Base::empty;
364  using _Base::max_size;
365 
366  // element access:
367 
368  reference
369  front()
370  {
371  __glibcxx_check_nonempty();
372  return _Base::front();
373  }
374 
375  const_reference
376  front() const
377  {
378  __glibcxx_check_nonempty();
379  return _Base::front();
380  }
381 
382  // modifiers:
383 
384  using _Base::emplace_front;
385  using _Base::push_front;
386 
387  void
388  pop_front()
389  {
390  __glibcxx_check_nonempty();
391  this->_M_invalidate_if([this](_Base_const_iterator __it)
392  { return __it == this->_M_base().cbegin(); });
393  _Base::pop_front();
394  }
395 
396  template<typename... _Args>
397  iterator
398  emplace_after(const_iterator __pos, _Args&&... __args)
399  {
400  __glibcxx_check_insert_after(__pos);
401  return { _Base::emplace_after(__pos.base(),
402  std::forward<_Args>(__args)...),
403  this };
404  }
405 
406  iterator
407  insert_after(const_iterator __pos, const _Tp& __val)
408  {
409  __glibcxx_check_insert_after(__pos);
410  return { _Base::insert_after(__pos.base(), __val), this };
411  }
412 
413  iterator
414  insert_after(const_iterator __pos, _Tp&& __val)
415  {
416  __glibcxx_check_insert_after(__pos);
417  return { _Base::insert_after(__pos.base(), std::move(__val)), this };
418  }
419 
420  iterator
421  insert_after(const_iterator __pos, size_type __n, const _Tp& __val)
422  {
423  __glibcxx_check_insert_after(__pos);
424  return { _Base::insert_after(__pos.base(), __n, __val), this };
425  }
426 
427  template<typename _InputIterator,
428  typename = std::_RequireInputIter<_InputIterator>>
429  iterator
430  insert_after(const_iterator __pos,
431  _InputIterator __first, _InputIterator __last)
432  {
433  typename __gnu_debug::_Distance_traits<_InputIterator>::__type __dist;
434  __glibcxx_check_insert_range_after(__pos, __first, __last, __dist);
435 
436  if (__dist.second >= __gnu_debug::__dp_sign)
437  return
438  {
439  _Base::insert_after(__pos.base(),
440  __gnu_debug::__unsafe(__first),
441  __gnu_debug::__unsafe(__last)),
442  this
443  };
444  else
445  return { _Base::insert_after(__pos.base(), __first, __last), this };
446  }
447 
448  iterator
449  insert_after(const_iterator __pos, std::initializer_list<_Tp> __il)
450  {
451  __glibcxx_check_insert_after(__pos);
452  return { _Base::insert_after(__pos.base(), __il), this };
453  }
454 
455  iterator
456  erase_after(const_iterator __pos)
457  {
458  __glibcxx_check_erase_after(__pos);
459 
460  _Base_const_iterator __next = std::next(__pos.base());
461  this->_M_invalidate_if([__next](_Base_const_iterator __it)
462  { return __it == __next; });
463  return { _Base::erase_after(__pos.base()), this };
464  }
465 
466  iterator
467  erase_after(const_iterator __pos, const_iterator __last)
468  {
469  __glibcxx_check_erase_range_after(__pos, __last);
470  for (_Base_const_iterator __victim = std::next(__pos.base());
471  __victim != __last.base(); ++__victim)
472  {
473  _GLIBCXX_DEBUG_VERIFY(__victim != _Base::cend(),
474  _M_message(__gnu_debug::__msg_valid_range2)
475  ._M_sequence(*this, "this")
476  ._M_iterator(__pos, "pos")
477  ._M_iterator(__last, "last"));
478  this->_M_invalidate_if([__victim](_Base_const_iterator __it)
479  { return __it == __victim; });
480  }
481 
482  return { _Base::erase_after(__pos.base(), __last.base()), this };
483  }
484 
485  void
486  swap(forward_list& __list)
487  noexcept( noexcept(declval<_Base&>().swap(__list)) )
488  {
489  _Safe::_M_swap(__list);
490  _Base::swap(__list);
491  }
492 
493  void
494  resize(size_type __sz)
495  {
496  this->_M_detach_singular();
497 
498  // if __sz < size(), invalidate all iterators in [begin+__sz, end()
499  _Base_iterator __victim = _Base::begin();
500  _Base_iterator __end = _Base::end();
501  for (size_type __i = __sz; __victim != __end && __i > 0; --__i)
502  ++__victim;
503 
504  for (; __victim != __end; ++__victim)
505  {
506  this->_M_invalidate_if([__victim](_Base_const_iterator __it)
507  { return __it == __victim; });
508  }
509 
510  __try
511  {
512  _Base::resize(__sz);
513  }
514  __catch(...)
515  {
516  this->_M_revalidate_singular();
517  __throw_exception_again;
518  }
519  }
520 
521  void
522  resize(size_type __sz, const value_type& __val)
523  {
524  this->_M_detach_singular();
525 
526  // if __sz < size(), invalidate all iterators in [begin+__sz, end())
527  _Base_iterator __victim = _Base::begin();
528  _Base_iterator __end = _Base::end();
529  for (size_type __i = __sz; __victim != __end && __i > 0; --__i)
530  ++__victim;
531 
532  for (; __victim != __end; ++__victim)
533  {
534  this->_M_invalidate_if([__victim](_Base_const_iterator __it)
535  { return __it == __victim; });
536  }
537 
538  __try
539  {
540  _Base::resize(__sz, __val);
541  }
542  __catch(...)
543  {
544  this->_M_revalidate_singular();
545  __throw_exception_again;
546  }
547  }
548 
549  void
550  clear() noexcept
551  {
552  _Base::clear();
553  this->_M_invalidate_all();
554  }
555 
556  // 23.2.3.5 forward_list operations:
557  void
558  splice_after(const_iterator __pos, forward_list&& __list)
559  {
560  __glibcxx_check_insert_after(__pos);
561  _GLIBCXX_DEBUG_VERIFY(std::__addressof(__list) != this,
562  _M_message(__gnu_debug::__msg_self_splice)
563  ._M_sequence(*this, "this"));
564  _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
565  _M_message(__gnu_debug::__msg_splice_alloc)
566  ._M_sequence(*this)
567  ._M_sequence(__list, "__list"));
568  this->_M_transfer_from_if(__list, [&__list](_Base_const_iterator __it)
569  {
570  return __it != __list._M_base().cbefore_begin()
571  && __it != __list._M_base().end();
572  });
573  _Base::splice_after(__pos.base(), std::move(__list._M_base()));
574  }
575 
576  void
577  splice_after(const_iterator __pos, forward_list& __list)
578  { splice_after(__pos, std::move(__list)); }
579 
580  void
581  splice_after(const_iterator __pos, forward_list&& __list,
582  const_iterator __i)
583  {
584  __glibcxx_check_insert_after(__pos);
585  _GLIBCXX_DEBUG_VERIFY(__i._M_before_dereferenceable(),
586  _M_message(__gnu_debug::__msg_splice_bad)
587  ._M_iterator(__i, "__i"));
588  _GLIBCXX_DEBUG_VERIFY(__i._M_attached_to(std::__addressof(__list)),
589  _M_message(__gnu_debug::__msg_splice_other)
590  ._M_iterator(__i, "__i")
591  ._M_sequence(__list, "__list"));
592  _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
593  _M_message(__gnu_debug::__msg_splice_alloc)
594  ._M_sequence(*this)
595  ._M_sequence(__list, "__list"));
596 
597  // _GLIBCXX_RESOLVE_LIB_DEFECTS
598  // 250. splicing invalidates iterators
599  _Base_const_iterator __next = std::next(__i.base());
600  this->_M_transfer_from_if(__list, [__next](_Base_const_iterator __it)
601  { return __it == __next; });
602  _Base::splice_after(__pos.base(), std::move(__list._M_base()),
603  __i.base());
604  }
605 
606  void
607  splice_after(const_iterator __pos, forward_list& __list,
608  const_iterator __i)
609  { splice_after(__pos, std::move(__list), __i); }
610 
611  void
612  splice_after(const_iterator __pos, forward_list&& __list,
613  const_iterator __before, const_iterator __last)
614  {
615  typename __gnu_debug::_Distance_traits<const_iterator>::__type __dist;
616  auto __listptr = std::__addressof(__list);
617  __glibcxx_check_insert_after(__pos);
618  __glibcxx_check_valid_fl_range(__before, __last, __dist);
619  _GLIBCXX_DEBUG_VERIFY(__before._M_attached_to(__listptr),
620  _M_message(__gnu_debug::__msg_splice_other)
621  ._M_sequence(__list, "list")
622  ._M_iterator(__before, "before"));
623  _GLIBCXX_DEBUG_VERIFY(__before._M_dereferenceable()
624  || __before._M_is_before_begin(),
625  _M_message(__gnu_debug::__msg_valid_range2)
626  ._M_sequence(__list, "list")
627  ._M_iterator(__before, "before")
628  ._M_iterator(__last, "last"));
629  _GLIBCXX_DEBUG_VERIFY(__before != __last,
630  _M_message(__gnu_debug::__msg_valid_range2)
631  ._M_sequence(__list, "list")
632  ._M_iterator(__before, "before")
633  ._M_iterator(__last, "last"));
634  _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
635  _M_message(__gnu_debug::__msg_splice_alloc)
636  ._M_sequence(*this)
637  ._M_sequence(__list, "__list"));
638 
639  for (_Base_const_iterator __tmp = std::next(__before.base());
640  __tmp != __last.base(); ++__tmp)
641  {
642  _GLIBCXX_DEBUG_VERIFY(__tmp != __list._M_base().end(),
643  _M_message(__gnu_debug::__msg_valid_range2)
644  ._M_sequence(__list, "list")
645  ._M_iterator(__before, "before")
646  ._M_iterator(__last, "last"));
647  _GLIBCXX_DEBUG_VERIFY(__listptr != this || __tmp != __pos.base(),
648  _M_message(__gnu_debug::__msg_splice_overlap)
649  ._M_iterator(__tmp, "position")
650  ._M_iterator(__before, "before")
651  ._M_iterator(__last, "last"));
652  // _GLIBCXX_RESOLVE_LIB_DEFECTS
653  // 250. splicing invalidates iterators
654  this->_M_transfer_from_if(__list, [__tmp](_Base_const_iterator __it)
655  { return __it == __tmp; });
656  }
657 
658  _Base::splice_after(__pos.base(), std::move(__list._M_base()),
659  __before.base(), __last.base());
660  }
661 
662  void
663  splice_after(const_iterator __pos, forward_list& __list,
664  const_iterator __before, const_iterator __last)
665  { splice_after(__pos, std::move(__list), __before, __last); }
666 
667  private:
668 #if __cplusplus > 201703L
669  using __remove_return_type = size_type;
670 # define _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG \
671  __attribute__((__abi_tag__("__cxx20")))
672 # define _GLIBCXX20_ONLY(__expr) __expr
673 #else
674  using __remove_return_type = void;
675 # define _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
676 # define _GLIBCXX20_ONLY(__expr)
677 #endif
678 
679  public:
680  _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
681  __remove_return_type
682  remove(const _Tp& __val)
683  {
684  if (!this->_M_iterators && !this->_M_const_iterators)
685  return _Base::remove(__val);
686 
687  size_type __removed __attribute__((__unused__)) = 0;
688  _Base __to_destroy(get_allocator());
689  _Base_const_iterator __x = _Base::cbefore_begin();
690  _Base_const_iterator __old = __x++;
691  while (__x != _Base::cend())
692  {
693  if (*__x == __val)
694  {
695  _Base_const_iterator __next = std::next(__old);
696  this->_M_invalidate_if([__next](_Base_const_iterator __it)
697  { return __it == __next; });
698  __to_destroy.splice_after(__to_destroy.cbefore_begin(),
699  _M_base(), __old);
700  __x = __old;
701  _GLIBCXX20_ONLY( __removed++ );
702  }
703 
704  __old = __x++;
705  }
706 
707  return _GLIBCXX20_ONLY( __removed );
708  }
709 
710  template<typename _Pred>
711  __remove_return_type
712  remove_if(_Pred __pred)
713  {
714  if (!this->_M_iterators && !this->_M_const_iterators)
715  return _Base::remove_if(__pred);
716 
717  size_type __removed __attribute__((__unused__)) = 0;
718  _Base __to_destroy(get_allocator());
719  _Base_iterator __x = _Base::before_begin();
720  _Base_iterator __old = __x++;
721  while (__x != _Base::end())
722  {
723  if (__pred(*__x))
724  {
725  this->_M_invalidate_if([__x](_Base_const_iterator __it)
726  { return __it == __x; });
727  __to_destroy.splice_after(__to_destroy.cbefore_begin(),
728  _M_base(), __old);
729  __x = __old;
730  _GLIBCXX20_ONLY( __removed++ );
731  }
732 
733  __old = __x++;
734  }
735 
736  return _GLIBCXX20_ONLY( __removed );
737  }
738 
739  _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
740  __remove_return_type
741  unique()
742  { return unique(std::equal_to<_Tp>()); }
743 
744  template<typename _BinPred>
745  __remove_return_type
746  unique(_BinPred __binary_pred)
747  {
748  if (!this->_M_iterators && !this->_M_const_iterators)
749  return _Base::unique(__binary_pred);
750 
751  _Base_const_iterator __first = _Base::cbegin();
752  _Base_const_iterator __last = _Base::cend();
753  if (__first == __last)
754  return _GLIBCXX20_ONLY(0);
755 
756  size_type __removed __attribute__((__unused__)) = 0;
757  _Base __to_destroy(get_allocator());
758  _Base_const_iterator __next = std::next(__first);
759  while (__next != __last)
760  {
761  if (__binary_pred(*__first, *__next))
762  {
763  this->_M_invalidate_if([__next](_Base_const_iterator __it)
764  { return __it == __next; });
765  __to_destroy.splice_after(__to_destroy.cbefore_begin(),
766  _M_base(), __first);
767  __next = __first;
768  _GLIBCXX20_ONLY( __removed++ );
769  }
770 
771  __first = __next++;
772  }
773 
774  return _GLIBCXX20_ONLY( __removed );
775  }
776 
777 #undef _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG
778 #undef _GLIBCXX20_ONLY
779 
780  void
781  merge(forward_list&& __list)
782  {
783  if (this != std::__addressof(__list))
784  {
785  __glibcxx_check_sorted(_Base::begin(), _Base::end());
786  __glibcxx_check_sorted(__list._M_base().begin(),
787  __list._M_base().end());
788  this->_M_transfer_from_if(__list, [&__list](_Base_const_iterator __it)
789  {
790  return __it != __list._M_base().cbefore_begin()
791  && __it != __list._M_base().cend();
792  });
793  _Base::merge(std::move(__list._M_base()));
794  }
795  }
796 
797  void
798  merge(forward_list& __list)
799  { merge(std::move(__list)); }
800 
801  template<typename _Comp>
802  void
803  merge(forward_list&& __list, _Comp __comp)
804  {
805  if (this != std::__addressof(__list))
806  {
807  __glibcxx_check_sorted_pred(_Base::begin(), _Base::end(), __comp);
808  __glibcxx_check_sorted_pred(__list._M_base().begin(),
809  __list._M_base().end(), __comp);
810  this->_M_transfer_from_if(__list,
811  [&__list](_Base_const_iterator __it)
812  {
813  return __it != __list._M_base().cbefore_begin()
814  && __it != __list._M_base().cend();
815  });
816  _Base::merge(std::move(__list._M_base()), __comp);
817  }
818  }
819 
820  template<typename _Comp>
821  void
822  merge(forward_list& __list, _Comp __comp)
823  { merge(std::move(__list), __comp); }
824 
825  using _Base::sort;
826  using _Base::reverse;
827 
828  _Base&
829  _M_base() noexcept { return *this; }
830 
831  const _Base&
832  _M_base() const noexcept { return *this; }
833  };
834 
835 #if __cpp_deduction_guides >= 201606
836  template<typename _InputIterator, typename _ValT
837  = typename iterator_traits<_InputIterator>::value_type,
838  typename _Allocator = allocator<_ValT>,
839  typename = _RequireInputIter<_InputIterator>,
840  typename = _RequireAllocator<_Allocator>>
841  forward_list(_InputIterator, _InputIterator, _Allocator = _Allocator())
842  -> forward_list<_ValT, _Allocator>;
843 #endif
844 
845  template<typename _Tp, typename _Alloc>
846  bool
847  operator==(const forward_list<_Tp, _Alloc>& __lx,
848  const forward_list<_Tp, _Alloc>& __ly)
849  { return __lx._M_base() == __ly._M_base(); }
850 
851 #if __cpp_lib_three_way_comparison
852  template<typename _Tp, typename _Alloc>
853  constexpr __detail::__synth3way_t<_Tp>
854  operator<=>(const forward_list<_Tp, _Alloc>& __x,
855  const forward_list<_Tp, _Alloc>& __y)
856  { return __x._M_base() <=> __y._M_base(); }
857 #else
858  template<typename _Tp, typename _Alloc>
859  inline bool
860  operator<(const forward_list<_Tp, _Alloc>& __lx,
861  const forward_list<_Tp, _Alloc>& __ly)
862  { return __lx._M_base() < __ly._M_base(); }
863 
864  template<typename _Tp, typename _Alloc>
865  inline bool
866  operator!=(const forward_list<_Tp, _Alloc>& __lx,
867  const forward_list<_Tp, _Alloc>& __ly)
868  { return !(__lx == __ly); }
869 
870  /// Based on operator<
871  template<typename _Tp, typename _Alloc>
872  inline bool
873  operator>(const forward_list<_Tp, _Alloc>& __lx,
874  const forward_list<_Tp, _Alloc>& __ly)
875  { return (__ly < __lx); }
876 
877  /// Based on operator<
878  template<typename _Tp, typename _Alloc>
879  inline bool
880  operator>=(const forward_list<_Tp, _Alloc>& __lx,
881  const forward_list<_Tp, _Alloc>& __ly)
882  { return !(__lx < __ly); }
883 
884  /// Based on operator<
885  template<typename _Tp, typename _Alloc>
886  inline bool
887  operator<=(const forward_list<_Tp, _Alloc>& __lx,
888  const forward_list<_Tp, _Alloc>& __ly)
889  { return !(__ly < __lx); }
890 #endif // three-way comparison
891 
892  /// See std::forward_list::swap().
893  template<typename _Tp, typename _Alloc>
894  inline void
895  swap(forward_list<_Tp, _Alloc>& __lx, forward_list<_Tp, _Alloc>& __ly)
896  noexcept(noexcept(__lx.swap(__ly)))
897  { __lx.swap(__ly); }
898 
899 } // namespace __debug
900 } // namespace std
901 
902 namespace __gnu_debug
903 {
904  template<typename _Tp, typename _Alloc>
905  struct _BeforeBeginHelper<std::__debug::forward_list<_Tp, _Alloc> >
906  {
907  typedef std::__debug::forward_list<_Tp, _Alloc> _Sequence;
908 
909  template<typename _Iterator>
910  static bool
911  _S_Is(const _Safe_iterator<_Iterator, _Sequence>& __it)
912  {
913  return
914  __it.base() == __it._M_get_sequence()->_M_base().before_begin();
915  }
916 
917  template<typename _Iterator>
918  static bool
919  _S_Is_Beginnest(const _Safe_iterator<_Iterator, _Sequence>& __it)
920  { return _S_Is(__it); }
921  };
922 
923  template<typename _Tp, typename _Alloc>
924  struct _Sequence_traits<std::__debug::forward_list<_Tp, _Alloc> >
925  {
926  typedef typename std::__debug::forward_list<_Tp, _Alloc>::iterator _It;
927 
928  static typename _Distance_traits<_It>::__type
929  _S_size(const std::__debug::forward_list<_Tp, _Alloc>& __seq)
930  {
931  return __seq.empty()
932  ? std::make_pair(0, __dp_exact) : std::make_pair(1, __dp_sign);
933  }
934  };
935 
936 #ifndef _GLIBCXX_DEBUG_PEDANTIC
937  template<class _Tp, class _Alloc>
938  struct _Insert_range_from_self_is_safe<
939  std::__debug::forward_list<_Tp, _Alloc> >
940  { enum { __value = 1 }; };
941 #endif
942 }
943 
944 #endif