libstdc++
debug/forward_list
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1 // <forward_list> -*- C++ -*-
2 
3 // Copyright (C) 2010-2018 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 <forward_list>
35 #include <debug/safe_sequence.h>
36 #include <debug/safe_container.h>
37 #include <debug/safe_iterator.h>
38 
39 // Special validity check for forward_list ranges.
40 #define __glibcxx_check_valid_fl_range(_First,_Last,_Dist) \
41 _GLIBCXX_DEBUG_VERIFY(_First._M_valid_range(_Last, _Dist, false), \
42  _M_message(__gnu_debug::__msg_valid_range) \
43  ._M_iterator(_First, #_First) \
44  ._M_iterator(_Last, #_Last))
45 
46 namespace __gnu_debug
47 {
48  /// Special iterators swap and invalidation for forward_list because of the
49  /// before_begin iterator.
50  template<typename _SafeSequence>
51  class _Safe_forward_list
52  : public _Safe_sequence<_SafeSequence>
53  {
54  _SafeSequence&
55  _M_this() noexcept
56  { return *static_cast<_SafeSequence*>(this); }
57 
58  static void
59  _M_swap_aux(_Safe_sequence_base& __lhs,
60  _Safe_iterator_base*& __lhs_iterators,
61  _Safe_sequence_base& __rhs,
62  _Safe_iterator_base*& __rhs_iterators);
63 
64  void _M_swap_single(_Safe_sequence_base&) noexcept;
65 
66  protected:
67  void
68  _M_invalidate_all()
69  {
70  using _Base_const_iterator = __decltype(_M_this()._M_base().cend());
71  this->_M_invalidate_if([this](_Base_const_iterator __it)
72  {
73  return __it != _M_this()._M_base().cbefore_begin()
74  && __it != _M_this()._M_base().cend(); });
75  }
76 
77  void _M_swap(_Safe_sequence_base&) noexcept;
78  };
79 
80  template<typename _SafeSequence>
81  void
82  _Safe_forward_list<_SafeSequence>::
83  _M_swap_aux(_Safe_sequence_base& __lhs,
84  _Safe_iterator_base*& __lhs_iterators,
85  _Safe_sequence_base& __rhs,
86  _Safe_iterator_base*& __rhs_iterators)
87  {
88  using const_iterator = typename _SafeSequence::const_iterator;
89  _Safe_iterator_base* __bbegin_its = 0;
90  _Safe_iterator_base* __last_bbegin = 0;
91  _SafeSequence& __rseq = static_cast<_SafeSequence&>(__rhs);
92 
93  for (_Safe_iterator_base* __iter = __lhs_iterators; __iter;)
94  {
95  // Even iterator is cast to const_iterator, not a problem.
96  _Safe_iterator_base* __victim_base = __iter;
97  const_iterator* __victim =
98  static_cast<const_iterator*>(__victim_base);
99  __iter = __iter->_M_next;
100  if (__victim->base() == __rseq._M_base().cbefore_begin())
101  {
102  __victim->_M_unlink();
103  if (__lhs_iterators == __victim_base)
104  __lhs_iterators = __victim_base->_M_next;
105  if (__bbegin_its)
106  {
107  __victim_base->_M_next = __bbegin_its;
108  __bbegin_its->_M_prior = __victim_base;
109  }
110  else
111  __last_bbegin = __victim_base;
112  __bbegin_its = __victim_base;
113  }
114  else
115  __victim_base->_M_sequence = std::__addressof(__lhs);
116  }
117 
118  if (__bbegin_its)
119  {
120  if (__rhs_iterators)
121  {
122  __rhs_iterators->_M_prior = __last_bbegin;
123  __last_bbegin->_M_next = __rhs_iterators;
124  }
125  __rhs_iterators = __bbegin_its;
126  }
127  }
128 
129  template<typename _SafeSequence>
130  void
131  _Safe_forward_list<_SafeSequence>::
132  _M_swap_single(_Safe_sequence_base& __other) noexcept
133  {
134  std::swap(_M_this()._M_iterators, __other._M_iterators);
135  std::swap(_M_this()._M_const_iterators, __other._M_const_iterators);
136  // Useless, always 1 on forward_list
137  //std::swap(_M_this()_M_version, __other._M_version);
138  _Safe_iterator_base* __this_its = _M_this()._M_iterators;
139  _M_swap_aux(__other, __other._M_iterators,
140  _M_this(), _M_this()._M_iterators);
141  _Safe_iterator_base* __this_const_its = _M_this()._M_const_iterators;
142  _M_swap_aux(__other, __other._M_const_iterators,
143  _M_this(), _M_this()._M_const_iterators);
144  _M_swap_aux(_M_this(), __this_its,
145  __other, __other._M_iterators);
146  _M_swap_aux(_M_this(), __this_const_its,
147  __other, __other._M_const_iterators);
148  }
149 
150  /* Special forward_list _M_swap version that does not swap the
151  * before-begin ownership.*/
152  template<typename _SafeSequence>
153  void
154  _Safe_forward_list<_SafeSequence>::
155  _M_swap(_Safe_sequence_base& __other) noexcept
156  {
157  // We need to lock both sequences to swap
158  using namespace __gnu_cxx;
159  __mutex *__this_mutex = &_M_this()._M_get_mutex();
160  __mutex *__other_mutex =
161  &static_cast<_SafeSequence&>(__other)._M_get_mutex();
162  if (__this_mutex == __other_mutex)
163  {
164  __scoped_lock __lock(*__this_mutex);
165  _M_swap_single(__other);
166  }
167  else
168  {
169  __scoped_lock __l1(__this_mutex < __other_mutex
170  ? *__this_mutex : *__other_mutex);
171  __scoped_lock __l2(__this_mutex < __other_mutex
172  ? *__other_mutex : *__this_mutex);
173  _M_swap_single(__other);
174  }
175  }
176 }
177 
178 namespace std _GLIBCXX_VISIBILITY(default)
179 {
180 namespace __debug
181 {
182  /// Class std::forward_list with safety/checking/debug instrumentation.
183  template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
184  class forward_list
185  : public __gnu_debug::_Safe_container<
186  forward_list<_Tp, _Alloc>, _Alloc, __gnu_debug::_Safe_forward_list>,
187  public _GLIBCXX_STD_C::forward_list<_Tp, _Alloc>
188  {
189  typedef _GLIBCXX_STD_C::forward_list<_Tp, _Alloc> _Base;
190  typedef __gnu_debug::_Safe_container<
191  forward_list, _Alloc, __gnu_debug::_Safe_forward_list> _Safe;
192 
193  typedef typename _Base::iterator _Base_iterator;
194  typedef typename _Base::const_iterator _Base_const_iterator;
195 
196  public:
197  typedef typename _Base::reference reference;
198  typedef typename _Base::const_reference const_reference;
199 
200  typedef __gnu_debug::_Safe_iterator<
201  _Base_iterator, forward_list> iterator;
202  typedef __gnu_debug::_Safe_iterator<
203  _Base_const_iterator, forward_list> const_iterator;
204 
205  typedef typename _Base::size_type size_type;
206  typedef typename _Base::difference_type difference_type;
207 
208  typedef _Tp value_type;
209  typedef typename _Base::allocator_type allocator_type;
210  typedef typename _Base::pointer pointer;
211  typedef typename _Base::const_pointer const_pointer;
212 
213  // 23.2.3.1 construct/copy/destroy:
214 
215  forward_list() = default;
216 
217  explicit
218  forward_list(const allocator_type& __al) noexcept
219  : _Base(__al) { }
220 
221  forward_list(const forward_list& __list, const allocator_type& __al)
222  : _Base(__list, __al)
223  { }
224 
225  forward_list(forward_list&& __list, const allocator_type& __al)
226  : _Safe(std::move(__list._M_safe()), __al),
227  _Base(std::move(__list._M_base()), __al)
228  { }
229 
230  explicit
231  forward_list(size_type __n, const allocator_type& __al = allocator_type())
232  : _Base(__n, __al)
233  { }
234 
235  forward_list(size_type __n, const _Tp& __value,
236  const allocator_type& __al = allocator_type())
237  : _Base(__n, __value, __al)
238  { }
239 
240  template<typename _InputIterator,
241  typename = std::_RequireInputIter<_InputIterator>>
242  forward_list(_InputIterator __first, _InputIterator __last,
243  const allocator_type& __al = allocator_type())
244  : _Base(__gnu_debug::__base(__gnu_debug::__check_valid_range(__first,
245  __last)),
246  __gnu_debug::__base(__last), __al)
247  { }
248 
249  forward_list(const forward_list&) = default;
250 
251  forward_list(forward_list&&) = default;
252 
253  forward_list(std::initializer_list<_Tp> __il,
254  const allocator_type& __al = allocator_type())
255  : _Base(__il, __al)
256  { }
257 
258  ~forward_list() = default;
259 
260  forward_list&
261  operator=(const forward_list&) = default;
262 
263  forward_list&
264  operator=(forward_list&&) = default;
265 
266  forward_list&
267  operator=(std::initializer_list<_Tp> __il)
268  {
269  _M_base() = __il;
270  this->_M_invalidate_all();
271  return *this;
272  }
273 
274  template<typename _InputIterator,
275  typename = std::_RequireInputIter<_InputIterator>>
276  void
277  assign(_InputIterator __first, _InputIterator __last)
278  {
279  typename __gnu_debug::_Distance_traits<_InputIterator>::__type __dist;
280  __glibcxx_check_valid_range2(__first, __last, __dist);
281 
282  if (__dist.second >= __gnu_debug::__dp_sign)
283  _Base::assign(__gnu_debug::__unsafe(__first),
284  __gnu_debug::__unsafe(__last));
285  else
286  _Base::assign(__first, __last);
287 
288  this->_M_invalidate_all();
289  }
290 
291  void
292  assign(size_type __n, const _Tp& __val)
293  {
294  _Base::assign(__n, __val);
295  this->_M_invalidate_all();
296  }
297 
298  void
299  assign(std::initializer_list<_Tp> __il)
300  {
301  _Base::assign(__il);
302  this->_M_invalidate_all();
303  }
304 
305  using _Base::get_allocator;
306 
307  // iterators:
308 
309  iterator
310  before_begin() noexcept
311  { return iterator(_Base::before_begin(), this); }
312 
313  const_iterator
314  before_begin() const noexcept
315  { return const_iterator(_Base::before_begin(), this); }
316 
317  iterator
318  begin() noexcept
319  { return iterator(_Base::begin(), this); }
320 
321  const_iterator
322  begin() const noexcept
323  { return const_iterator(_Base::begin(), this); }
324 
325  iterator
326  end() noexcept
327  { return iterator(_Base::end(), this); }
328 
329  const_iterator
330  end() const noexcept
331  { return const_iterator(_Base::end(), this); }
332 
333  const_iterator
334  cbegin() const noexcept
335  { return const_iterator(_Base::cbegin(), this); }
336 
337  const_iterator
338  cbefore_begin() const noexcept
339  { return const_iterator(_Base::cbefore_begin(), this); }
340 
341  const_iterator
342  cend() const noexcept
343  { return const_iterator(_Base::cend(), this); }
344 
345  using _Base::empty;
346  using _Base::max_size;
347 
348  // element access:
349 
350  reference
351  front()
352  {
353  __glibcxx_check_nonempty();
354  return _Base::front();
355  }
356 
357  const_reference
358  front() const
359  {
360  __glibcxx_check_nonempty();
361  return _Base::front();
362  }
363 
364  // modiļ¬ers:
365 
366  using _Base::emplace_front;
367  using _Base::push_front;
368 
369  void
370  pop_front()
371  {
372  __glibcxx_check_nonempty();
373  this->_M_invalidate_if([this](_Base_const_iterator __it)
374  { return __it == this->_M_base().cbegin(); });
375  _Base::pop_front();
376  }
377 
378  template<typename... _Args>
379  iterator
380  emplace_after(const_iterator __pos, _Args&&... __args)
381  {
382  __glibcxx_check_insert_after(__pos);
383  return iterator(_Base::emplace_after(__pos.base(),
384  std::forward<_Args>(__args)...),
385  this);
386  }
387 
388  iterator
389  insert_after(const_iterator __pos, const _Tp& __val)
390  {
391  __glibcxx_check_insert_after(__pos);
392  return iterator(_Base::insert_after(__pos.base(), __val), this);
393  }
394 
395  iterator
396  insert_after(const_iterator __pos, _Tp&& __val)
397  {
398  __glibcxx_check_insert_after(__pos);
399  return iterator(_Base::insert_after(__pos.base(), std::move(__val)),
400  this);
401  }
402 
403  iterator
404  insert_after(const_iterator __pos, size_type __n, const _Tp& __val)
405  {
406  __glibcxx_check_insert_after(__pos);
407  return iterator(_Base::insert_after(__pos.base(), __n, __val),
408  this);
409  }
410 
411  template<typename _InputIterator,
412  typename = std::_RequireInputIter<_InputIterator>>
413  iterator
414  insert_after(const_iterator __pos,
415  _InputIterator __first, _InputIterator __last)
416  {
417  typename __gnu_debug::_Distance_traits<_InputIterator>::__type __dist;
418  __glibcxx_check_insert_range_after(__pos, __first, __last, __dist);
419 
420  if (__dist.second >= __gnu_debug::__dp_sign)
421  return
422  {
423  _Base::insert_after(__pos.base(),
424  __gnu_debug::__unsafe(__first),
425  __gnu_debug::__unsafe(__last)),
426  this
427  };
428  else
429  return { _Base::insert_after(__pos.base(), __first, __last), this };
430  }
431 
432  iterator
433  insert_after(const_iterator __pos, std::initializer_list<_Tp> __il)
434  {
435  __glibcxx_check_insert_after(__pos);
436  return iterator(_Base::insert_after(__pos.base(), __il), this);
437  }
438 
439  private:
440  _Base_iterator
441  _M_erase_after(_Base_const_iterator __pos)
442  {
443  _Base_const_iterator __next = std::next(__pos);
444  this->_M_invalidate_if([__next](_Base_const_iterator __it)
445  { return __it == __next; });
446  return _Base::erase_after(__pos);
447  }
448  public:
449  iterator
450  erase_after(const_iterator __pos)
451  {
452  __glibcxx_check_erase_after(__pos);
453  return iterator(_M_erase_after(__pos.base()), this);
454  }
455 
456  iterator
457  erase_after(const_iterator __pos, const_iterator __last)
458  {
459  __glibcxx_check_erase_range_after(__pos, __last);
460  for (_Base_const_iterator __victim = std::next(__pos.base());
461  __victim != __last.base(); ++__victim)
462  {
463  _GLIBCXX_DEBUG_VERIFY(__victim != _Base::end(),
464  _M_message(__gnu_debug::__msg_valid_range2)
465  ._M_sequence(*this, "this")
466  ._M_iterator(__pos, "pos")
467  ._M_iterator(__last, "last"));
468  this->_M_invalidate_if([__victim](_Base_const_iterator __it)
469  { return __it == __victim; });
470  }
471  return iterator(_Base::erase_after(__pos.base(), __last.base()), this);
472  }
473 
474  void
475  swap(forward_list& __list)
476  noexcept( noexcept(declval<_Base&>().swap(__list)) )
477  {
478  _Safe::_M_swap(__list);
479  _Base::swap(__list);
480  }
481 
482  void
483  resize(size_type __sz)
484  {
485  this->_M_detach_singular();
486 
487  // if __sz < size(), invalidate all iterators in [begin+__sz, end()
488  _Base_iterator __victim = _Base::begin();
489  _Base_iterator __end = _Base::end();
490  for (size_type __i = __sz; __victim != __end && __i > 0; --__i)
491  ++__victim;
492 
493  for (; __victim != __end; ++__victim)
494  {
495  this->_M_invalidate_if([__victim](_Base_const_iterator __it)
496  { return __it == __victim; });
497  }
498 
499  __try
500  {
501  _Base::resize(__sz);
502  }
503  __catch(...)
504  {
505  this->_M_revalidate_singular();
506  __throw_exception_again;
507  }
508  }
509 
510  void
511  resize(size_type __sz, const value_type& __val)
512  {
513  this->_M_detach_singular();
514 
515  // if __sz < size(), invalidate all iterators in [begin+__sz, end())
516  _Base_iterator __victim = _Base::begin();
517  _Base_iterator __end = _Base::end();
518  for (size_type __i = __sz; __victim != __end && __i > 0; --__i)
519  ++__victim;
520 
521  for (; __victim != __end; ++__victim)
522  {
523  this->_M_invalidate_if([__victim](_Base_const_iterator __it)
524  { return __it == __victim; });
525  }
526 
527  __try
528  {
529  _Base::resize(__sz, __val);
530  }
531  __catch(...)
532  {
533  this->_M_revalidate_singular();
534  __throw_exception_again;
535  }
536  }
537 
538  void
539  clear() noexcept
540  {
541  _Base::clear();
542  this->_M_invalidate_all();
543  }
544 
545  // 23.2.3.5 forward_list operations:
546  void
547  splice_after(const_iterator __pos, forward_list&& __list)
548  {
549  __glibcxx_check_insert_after(__pos);
550  _GLIBCXX_DEBUG_VERIFY(std::__addressof(__list) != this,
551  _M_message(__gnu_debug::__msg_self_splice)
552  ._M_sequence(*this, "this"));
553  _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
554  _M_message(__gnu_debug::__msg_splice_alloc)
555  ._M_sequence(*this)
556  ._M_sequence(__list, "__list"));
557  this->_M_transfer_from_if(__list, [&__list](_Base_const_iterator __it)
558  {
559  return __it != __list._M_base().cbefore_begin()
560  && __it != __list._M_base().end();
561  });
562  _Base::splice_after(__pos.base(), std::move(__list._M_base()));
563  }
564 
565  void
566  splice_after(const_iterator __pos, forward_list& __list)
567  { splice_after(__pos, std::move(__list)); }
568 
569  void
570  splice_after(const_iterator __pos, forward_list&& __list,
571  const_iterator __i)
572  {
573  __glibcxx_check_insert_after(__pos);
574  _GLIBCXX_DEBUG_VERIFY(__i._M_before_dereferenceable(),
575  _M_message(__gnu_debug::__msg_splice_bad)
576  ._M_iterator(__i, "__i"));
577  _GLIBCXX_DEBUG_VERIFY(__i._M_attached_to(std::__addressof(__list)),
578  _M_message(__gnu_debug::__msg_splice_other)
579  ._M_iterator(__i, "__i")
580  ._M_sequence(__list, "__list"));
581  _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
582  _M_message(__gnu_debug::__msg_splice_alloc)
583  ._M_sequence(*this)
584  ._M_sequence(__list, "__list"));
585 
586  // _GLIBCXX_RESOLVE_LIB_DEFECTS
587  // 250. splicing invalidates iterators
588  _Base_const_iterator __next = std::next(__i.base());
589  this->_M_transfer_from_if(__list, [__next](_Base_const_iterator __it)
590  { return __it == __next; });
591  _Base::splice_after(__pos.base(), std::move(__list._M_base()),
592  __i.base());
593  }
594 
595  void
596  splice_after(const_iterator __pos, forward_list& __list,
597  const_iterator __i)
598  { splice_after(__pos, std::move(__list), __i); }
599 
600  void
601  splice_after(const_iterator __pos, forward_list&& __list,
602  const_iterator __before, const_iterator __last)
603  {
604  typename __gnu_debug::_Distance_traits<const_iterator>::__type __dist;
605  auto __listptr = std::__addressof(__list);
606  __glibcxx_check_insert_after(__pos);
607  __glibcxx_check_valid_fl_range(__before, __last, __dist);
608  _GLIBCXX_DEBUG_VERIFY(__before._M_attached_to(__listptr),
609  _M_message(__gnu_debug::__msg_splice_other)
610  ._M_sequence(__list, "list")
611  ._M_iterator(__before, "before"));
612  _GLIBCXX_DEBUG_VERIFY(__before._M_dereferenceable()
613  || __before._M_is_before_begin(),
614  _M_message(__gnu_debug::__msg_valid_range2)
615  ._M_sequence(__list, "list")
616  ._M_iterator(__before, "before")
617  ._M_iterator(__last, "last"));
618  _GLIBCXX_DEBUG_VERIFY(__before != __last,
619  _M_message(__gnu_debug::__msg_valid_range2)
620  ._M_sequence(__list, "list")
621  ._M_iterator(__before, "before")
622  ._M_iterator(__last, "last"));
623  _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
624  _M_message(__gnu_debug::__msg_splice_alloc)
625  ._M_sequence(*this)
626  ._M_sequence(__list, "__list"));
627 
628  for (_Base_const_iterator __tmp = std::next(__before.base());
629  __tmp != __last.base(); ++__tmp)
630  {
631  _GLIBCXX_DEBUG_VERIFY(__tmp != __list._M_base().end(),
632  _M_message(__gnu_debug::__msg_valid_range2)
633  ._M_sequence(__list, "list")
634  ._M_iterator(__before, "before")
635  ._M_iterator(__last, "last"));
636  _GLIBCXX_DEBUG_VERIFY(__listptr != this || __tmp != __pos.base(),
637  _M_message(__gnu_debug::__msg_splice_overlap)
638  ._M_iterator(__tmp, "position")
639  ._M_iterator(__before, "before")
640  ._M_iterator(__last, "last"));
641  // _GLIBCXX_RESOLVE_LIB_DEFECTS
642  // 250. splicing invalidates iterators
643  this->_M_transfer_from_if(__list, [__tmp](_Base_const_iterator __it)
644  { return __it == __tmp; });
645  }
646 
647  _Base::splice_after(__pos.base(), std::move(__list._M_base()),
648  __before.base(), __last.base());
649  }
650 
651  void
652  splice_after(const_iterator __pos, forward_list& __list,
653  const_iterator __before, const_iterator __last)
654  { splice_after(__pos, std::move(__list), __before, __last); }
655 
656  void
657  remove(const _Tp& __val)
658  {
659  _Base_iterator __x = _Base::before_begin();
660  _Base_iterator __old = __x++;
661  while (__x != _Base::end())
662  {
663  if (*__x == __val)
664  __x = _M_erase_after(__old);
665  else
666  __old = __x++;
667  }
668  }
669 
670  template<typename _Pred>
671  void
672  remove_if(_Pred __pred)
673  {
674  _Base_iterator __x = _Base::before_begin();
675  _Base_iterator __old = __x++;
676  while (__x != _Base::end())
677  {
678  if (__pred(*__x))
679  __x = _M_erase_after(__old);
680  else
681  __old = __x++;
682  }
683  }
684 
685  void
686  unique()
687  {
688  _Base_iterator __first = _Base::begin();
689  _Base_iterator __last = _Base::end();
690  if (__first == __last)
691  return;
692  _Base_iterator __next = std::next(__first);
693  while (__next != __last)
694  {
695  if (*__first == *__next)
696  __next = _M_erase_after(__first);
697  else
698  __first = __next++;
699  }
700  }
701 
702  template<typename _BinPred>
703  void
704  unique(_BinPred __binary_pred)
705  {
706  _Base_iterator __first = _Base::begin();
707  _Base_iterator __last = _Base::end();
708  if (__first == __last)
709  return;
710  _Base_iterator __next = std::next(__first);
711  while (__next != __last)
712  {
713  if (__binary_pred(*__first, *__next))
714  __next = _M_erase_after(__first);
715  else
716  __first = __next++;
717  }
718  }
719 
720  void
721  merge(forward_list&& __list)
722  {
723  if (this != std::__addressof(__list))
724  {
725  __glibcxx_check_sorted(_Base::begin(), _Base::end());
726  __glibcxx_check_sorted(__list._M_base().begin(),
727  __list._M_base().end());
728  this->_M_transfer_from_if(__list, [&__list](_Base_const_iterator __it)
729  {
730  return __it != __list._M_base().cbefore_begin()
731  && __it != __list._M_base().cend();
732  });
733  _Base::merge(std::move(__list._M_base()));
734  }
735  }
736 
737  void
738  merge(forward_list& __list)
739  { merge(std::move(__list)); }
740 
741  template<typename _Comp>
742  void
743  merge(forward_list&& __list, _Comp __comp)
744  {
745  if (this != std::__addressof(__list))
746  {
747  __glibcxx_check_sorted_pred(_Base::begin(), _Base::end(), __comp);
748  __glibcxx_check_sorted_pred(__list._M_base().begin(),
749  __list._M_base().end(), __comp);
750  this->_M_transfer_from_if(__list,
751  [&__list](_Base_const_iterator __it)
752  {
753  return __it != __list._M_base().cbefore_begin()
754  && __it != __list._M_base().cend();
755  });
756  _Base::merge(std::move(__list._M_base()), __comp);
757  }
758  }
759 
760  template<typename _Comp>
761  void
762  merge(forward_list& __list, _Comp __comp)
763  { merge(std::move(__list), __comp); }
764 
765  using _Base::sort;
766  using _Base::reverse;
767 
768  _Base&
769  _M_base() noexcept { return *this; }
770 
771  const _Base&
772  _M_base() const noexcept { return *this; }
773  };
774 
775 #if __cpp_deduction_guides >= 201606
776  template<typename _InputIterator, typename _ValT
777  = typename iterator_traits<_InputIterator>::value_type,
778  typename _Allocator = allocator<_ValT>,
779  typename = _RequireInputIter<_InputIterator>,
780  typename = _RequireAllocator<_Allocator>>
781  forward_list(_InputIterator, _InputIterator, _Allocator = _Allocator())
782  -> forward_list<_ValT, _Allocator>;
783 #endif
784 
785  template<typename _Tp, typename _Alloc>
786  bool
787  operator==(const forward_list<_Tp, _Alloc>& __lx,
788  const forward_list<_Tp, _Alloc>& __ly)
789  { return __lx._M_base() == __ly._M_base(); }
790 
791  template<typename _Tp, typename _Alloc>
792  inline bool
793  operator<(const forward_list<_Tp, _Alloc>& __lx,
794  const forward_list<_Tp, _Alloc>& __ly)
795  { return __lx._M_base() < __ly._M_base(); }
796 
797  template<typename _Tp, typename _Alloc>
798  inline bool
799  operator!=(const forward_list<_Tp, _Alloc>& __lx,
800  const forward_list<_Tp, _Alloc>& __ly)
801  { return !(__lx == __ly); }
802 
803  /// Based on operator<
804  template<typename _Tp, typename _Alloc>
805  inline bool
806  operator>(const forward_list<_Tp, _Alloc>& __lx,
807  const forward_list<_Tp, _Alloc>& __ly)
808  { return (__ly < __lx); }
809 
810  /// Based on operator<
811  template<typename _Tp, typename _Alloc>
812  inline bool
813  operator>=(const forward_list<_Tp, _Alloc>& __lx,
814  const forward_list<_Tp, _Alloc>& __ly)
815  { return !(__lx < __ly); }
816 
817  /// Based on operator<
818  template<typename _Tp, typename _Alloc>
819  inline bool
820  operator<=(const forward_list<_Tp, _Alloc>& __lx,
821  const forward_list<_Tp, _Alloc>& __ly)
822  { return !(__ly < __lx); }
823 
824  /// See std::forward_list::swap().
825  template<typename _Tp, typename _Alloc>
826  inline void
827  swap(forward_list<_Tp, _Alloc>& __lx, forward_list<_Tp, _Alloc>& __ly)
828  noexcept(noexcept(__lx.swap(__ly)))
829  { __lx.swap(__ly); }
830 
831 } // namespace __debug
832 } // namespace std
833 
834 namespace __gnu_debug
835 {
836  template<typename _Tp, typename _Alloc>
837  struct _BeforeBeginHelper<std::__debug::forward_list<_Tp, _Alloc> >
838  {
839  typedef std::__debug::forward_list<_Tp, _Alloc> _Sequence;
840 
841  template<typename _Iterator>
842  static bool
843  _S_Is(const _Safe_iterator<_Iterator, _Sequence>& __it)
844  {
845  return
846  __it.base() == __it._M_get_sequence()->_M_base().before_begin();
847  }
848 
849  template<typename _Iterator>
850  static bool
851  _S_Is_Beginnest(const _Safe_iterator<_Iterator, _Sequence>& __it)
852  { return _S_Is(__it); }
853  };
854 
855  template<typename _Tp, typename _Alloc>
856  struct _Sequence_traits<std::__debug::forward_list<_Tp, _Alloc> >
857  {
858  typedef typename std::__debug::forward_list<_Tp, _Alloc>::iterator _It;
859 
860  static typename _Distance_traits<_It>::__type
861  _S_size(const std::__debug::forward_list<_Tp, _Alloc>& __seq)
862  {
863  return __seq.empty()
864  ? std::make_pair(0, __dp_exact) : std::make_pair(1, __dp_equality);
865  }
866  };
867 
868 #ifndef _GLIBCXX_DEBUG_PEDANTIC
869  template<class _Tp, class _Alloc>
870  struct _Insert_range_from_self_is_safe<
871  std::__debug::forward_list<_Tp, _Alloc> >
872  { enum { __value = 1 }; };
873 #endif
874 }
875 
876 #endif