libstdc++-v3/include/debug/forward_list

   1 // <forward_list> -*- C++ -*-
   2
   3 // Copyright (C) 2010-2013 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_iterator.h>
  37
  38 namespace std _GLIBCXX_VISIBILITY(default)
  39 {
  40 namespace __debug
  41 {
  42   /// Class std::forward_list with safety/checking/debug instrumentation.
  43   template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
  44     class forward_list
  45     : public _GLIBCXX_STD_C::forward_list<_Tp, _Alloc>,
  46       public __gnu_debug::_Safe_sequence<forward_list<_Tp, _Alloc> >
  47     {
  48       typedef _GLIBCXX_STD_C::forward_list<_Tp, _Alloc> _Base;
  49
  50       typedef typename _Base::iterator       _Base_iterator;
  51       typedef typename _Base::const_iterator _Base_const_iterator;
  52
  53       typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
  54         rebind<_GLIBCXX_STD_C::_Fwd_list_node<_Tp>>::other _Node_alloc_type;
  55
  56       typedef __gnu_cxx::__alloc_traits<_Node_alloc_type> _Node_alloc_traits;
  57
  58     public:
  59       typedef typename _Base::reference             reference;
  60       typedef typename _Base::const_reference       const_reference;
  61
  62       typedef __gnu_debug::_Safe_iterator<_Base_iterator,
  63                                           forward_list> iterator;
  64       typedef __gnu_debug::_Safe_iterator<_Base_const_iterator,
  65                                           forward_list> const_iterator;
  66
  67       typedef typename _Base::size_type             size_type;
  68       typedef typename _Base::difference_type       difference_type;
  69
  70       typedef _Tp                                   value_type;
  71       typedef _Alloc                                allocator_type;
  72       typedef typename _Base::pointer               pointer;
  73       typedef typename _Base::const_pointer         const_pointer;
  74
  75       // 23.2.3.1 construct/copy/destroy:
  76       explicit
  77       forward_list(const _Alloc& __al = _Alloc())
  78       : _Base(__al) { }
  79
  80       forward_list(const forward_list& __list, const _Alloc& __al)
  81       : _Base(__list, __al)
  82       { }
  83
  84       forward_list(forward_list&& __list, const _Alloc& __al)
  85       : _Base(std::move(__list._M_base()), __al)
  86       {
  87         if (__list.get_allocator() == __al)
  88           this->_M_swap(__list);
  89         else
  90           __list._M_invalidate_all();
  91       }
  92
  93       explicit
  94       forward_list(size_type __n, const _Alloc& __al = _Alloc())
  95       : _Base(__n, __al)
  96       { }
  97
  98       forward_list(size_type __n, const _Tp& __value,
  99                    const _Alloc& __al = _Alloc())
 100       : _Base(__n, __value, __al)
 101       { }
 102
 103       template<typename _InputIterator,
 104                typename = std::_RequireInputIter<_InputIterator>>
 105         forward_list(_InputIterator __first, _InputIterator __last,
 106                      const _Alloc& __al = _Alloc())
 107         : _Base(__gnu_debug::__base(__gnu_debug::__check_valid_range(__first,
 108                                                                      __last)),
 109                 __gnu_debug::__base(__last), __al)
 110         { }
 111
 112       forward_list(const forward_list& __list)
 113       : _Base(__list)
 114       { }
 115
 116       forward_list(forward_list&& __list) noexcept
 117       : _Base(std::move(__list._M_base()))
 118       {
 119         this->_M_swap(__list);
 120       }
 121
 122       forward_list(std::initializer_list<_Tp> __il,
 123                    const _Alloc& __al = _Alloc())
 124       : _Base(__il, __al)
 125       { }
 126
 127       ~forward_list() noexcept
 128       { }
 129
 130       forward_list&
 131       operator=(const forward_list& __list)
 132       {
 133         static_cast<_Base&>(*this) = __list;
 134         this->_M_invalidate_all();
 135         return *this;
 136       }
 137
 138       forward_list&
 139       operator=(forward_list&& __list)
 140       noexcept(_Node_alloc_traits::_S_nothrow_move())
 141       {
 142         __glibcxx_check_self_move_assign(__list);
 143         bool xfer_memory = _Node_alloc_traits::_S_propagate_on_move_assign()
 144             || __list.get_allocator() == this->get_allocator();
 145         static_cast<_Base&>(*this) = std::move(__list);
 146         if (xfer_memory)
 147           this->_M_swap(__list);
 148         else
 149           this->_M_invalidate_all();
 150         __list._M_invalidate_all();
 151         return *this;
 152       }
 153
 154       forward_list&
 155       operator=(std::initializer_list<_Tp> __il)
 156       {
 157         static_cast<_Base&>(*this) = __il;
 158         this->_M_invalidate_all();
 159         return *this;
 160       }
 161
 162       template<typename _InputIterator,
 163                typename = std::_RequireInputIter<_InputIterator>>
 164         void
 165         assign(_InputIterator __first, _InputIterator __last)
 166         {
 167           __glibcxx_check_valid_range(__first, __last);
 168           _Base::assign(__gnu_debug::__base(__first),
 169                         __gnu_debug::__base(__last));
 170           this->_M_invalidate_all();
 171         }
 172
 173       void
 174       assign(size_type __n, const _Tp& __val)
 175       {
 176         _Base::assign(__n, __val);
 177         this->_M_invalidate_all();
 178       }
 179
 180       void
 181       assign(std::initializer_list<_Tp> __il)
 182       {
 183         _Base::assign(__il);
 184         this->_M_invalidate_all();
 185       }
 186
 187       using _Base::get_allocator;
 188
 189       // iterators:
 190
 191       iterator
 192       before_begin() noexcept
 193       { return iterator(_Base::before_begin(), this); }
 194
 195       const_iterator
 196       before_begin() const noexcept
 197       { return const_iterator(_Base::before_begin(), this); }
 198
 199       iterator
 200       begin() noexcept
 201       { return iterator(_Base::begin(), this); }
 202
 203       const_iterator
 204       begin() const noexcept
 205       { return const_iterator(_Base::begin(), this); }
 206
 207       iterator
 208       end() noexcept
 209       { return iterator(_Base::end(), this); }
 210
 211       const_iterator
 212       end() const noexcept
 213       { return const_iterator(_Base::end(), this); }
 214
 215       const_iterator
 216       cbegin() const noexcept
 217       { return const_iterator(_Base::cbegin(), this); }
 218
 219       const_iterator
 220       cbefore_begin() const noexcept
 221       { return const_iterator(_Base::cbefore_begin(), this); }
 222
 223       const_iterator
 224       cend() const noexcept
 225       { return const_iterator(_Base::cend(), this); }
 226
 227       using _Base::empty;
 228       using _Base::max_size;
 229
 230       // element access:
 231
 232       reference
 233       front()
 234       {
 235         __glibcxx_check_nonempty();
 236         return _Base::front();
 237       }
 238
 239       const_reference
 240       front() const
 241       {
 242         __glibcxx_check_nonempty();
 243         return _Base::front();
 244       }
 245
 246       // modiﬁers:
 247
 248       using _Base::emplace_front;
 249       using _Base::push_front;
 250
 251       void
 252       pop_front()
 253       {
 254         __glibcxx_check_nonempty();
 255         this->_M_invalidate_if([this](_Base_const_iterator __it)
 256           { return __it == this->_M_base().cbegin(); });
 257         _Base::pop_front();
 258       }
 259
 260       template<typename... _Args>
 261         iterator
 262         emplace_after(const_iterator __pos, _Args&&... __args)
 263         {
 264           __glibcxx_check_insert_after(__pos);
 265           return iterator(_Base::emplace_after(__pos.base(),
 266                                         std::forward<_Args>(__args)...),
 267                           this);
 268         }
 269
 270       iterator
 271       insert_after(const_iterator __pos, const _Tp& __val)
 272       {
 273         __glibcxx_check_insert_after(__pos);
 274         return iterator(_Base::insert_after(__pos.base(), __val), this);
 275       }
 276
 277       iterator
 278       insert_after(const_iterator __pos, _Tp&& __val)
 279       {
 280         __glibcxx_check_insert_after(__pos);
 281         return iterator(_Base::insert_after(__pos.base(), std::move(__val)),
 282                         this);
 283       }
 284
 285       iterator
 286       insert_after(const_iterator __pos, size_type __n, const _Tp& __val)
 287       {
 288         __glibcxx_check_insert_after(__pos);
 289         return iterator(_Base::insert_after(__pos.base(), __n, __val),
 290                         this);
 291       }
 292
 293       template<typename _InputIterator,
 294                typename = std::_RequireInputIter<_InputIterator>>
 295         iterator
 296         insert_after(const_iterator __pos,
 297                      _InputIterator __first, _InputIterator __last)
 298         {
 299           __glibcxx_check_insert_range_after(__pos, __first, __last);
 300           return iterator(_Base::insert_after(__pos.base(),
 301                                               __gnu_debug::__base(__first),
 302                                               __gnu_debug::__base(__last)),
 303                           this);
 304         }
 305
 306       iterator
 307       insert_after(const_iterator __pos, std::initializer_list<_Tp> __il)
 308       {
 309         __glibcxx_check_insert_after(__pos);
 310         return iterator(_Base::insert_after(__pos.base(), __il), this);
 311       }
 312
 313     private:
 314       _Base_iterator
 315       _M_erase_after(_Base_const_iterator __pos)
 316       {
 317         _Base_const_iterator __next = std::next(__pos);
 318         this->_M_invalidate_if([__next](_Base_const_iterator __it)
 319           { return __it == __next; });
 320         return _Base::erase_after(__pos);
 321       }
 322     public:
 323       iterator
 324       erase_after(const_iterator __pos)
 325       {
 326         __glibcxx_check_erase_after(__pos);
 327         return iterator(_M_erase_after(__pos.base()), this);
 328       }
 329
 330       iterator
 331       erase_after(const_iterator __pos, const_iterator __last)
 332       {
 333         __glibcxx_check_erase_range_after(__pos, __last);
 334         for (_Base_const_iterator __victim = std::next(__pos.base());
 335             __victim != __last.base(); ++__victim)
 336           {
 337             _GLIBCXX_DEBUG_VERIFY(__victim != _Base::end(),
 338                                   _M_message(__gnu_debug::__msg_valid_range2)
 339                                   ._M_sequence(*this, "this")
 340                                   ._M_iterator(__pos, "pos")
 341                                   ._M_iterator(__last, "last"));
 342             this->_M_invalidate_if([__victim](_Base_const_iterator __it)
 343               { return __it == __victim; });
 344           }
 345         return iterator(_Base::erase_after(__pos.base(), __last.base()), this);
 346       }
 347
 348       void
 349       swap(forward_list& __list)
 350       noexcept(_Node_alloc_traits::_S_nothrow_swap())
 351       {
 352         if (!_Node_alloc_traits::_S_propagate_on_swap())
 353           __glibcxx_check_equal_allocs(__list);
 354         _Base::swap(__list);
 355         this->_M_swap(__list);
 356       }
 357
 358       void
 359       resize(size_type __sz)
 360       {
 361         this->_M_detach_singular();
 362
 363         // if __sz < size(), invalidate all iterators in [begin+__sz, end()
 364         _Base_iterator __victim = _Base::begin();
 365         _Base_iterator __end = _Base::end();
 366         for (size_type __i = __sz; __victim != __end && __i > 0; --__i)
 367           ++__victim;
 368
 369         for (; __victim != __end; ++__victim)
 370           {
 371             this->_M_invalidate_if([__victim](_Base_const_iterator __it)
 372               { return __it == __victim; });
 373           }
 374
 375         __try
 376           {
 377             _Base::resize(__sz);
 378           }
 379         __catch(...)
 380           {
 381             this->_M_revalidate_singular();
 382             __throw_exception_again;
 383           }
 384       }
 385
 386       void
 387       resize(size_type __sz, const value_type& __val)
 388       {
 389         this->_M_detach_singular();
 390
 391         // if __sz < size(), invalidate all iterators in [begin+__sz, end())
 392         _Base_iterator __victim = _Base::begin();
 393         _Base_iterator __end = _Base::end();
 394         for (size_type __i = __sz; __victim != __end && __i > 0; --__i)
 395           ++__victim;
 396
 397         for (; __victim != __end; ++__victim)
 398           {
 399             this->_M_invalidate_if([__victim](_Base_const_iterator __it)
 400               { return __it == __victim; });
 401           }
 402
 403         __try
 404           {
 405             _Base::resize(__sz, __val);
 406           }
 407         __catch(...)
 408           {
 409             this->_M_revalidate_singular();
 410             __throw_exception_again;
 411           }
 412       }
 413
 414       void
 415       clear() noexcept
 416       {
 417         _Base::clear();
 418         this->_M_invalidate_all();
 419       }
 420
 421       // 23.2.3.5 forward_list operations:
 422       void
 423       splice_after(const_iterator __pos, forward_list&& __list)
 424       {
 425         __glibcxx_check_insert_after(__pos);
 426         _GLIBCXX_DEBUG_VERIFY(&__list != this,
 427                               _M_message(__gnu_debug::__msg_self_splice)
 428                               ._M_sequence(*this, "this"));
 429         _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
 430                               _M_message(__gnu_debug::__msg_splice_alloc)
 431                               ._M_sequence(*this)
 432                               ._M_sequence(__list, "__list"));
 433         this->_M_transfer_from_if(__list, [&__list](_Base_const_iterator __it)
 434           {
 435             return __it != __list._M_base().cbefore_begin()
 436                    && __it != __list._M_base().end();
 437           });
 438         _Base::splice_after(__pos.base(), std::move(__list._M_base()));
 439       }
 440
 441       void
 442       splice_after(const_iterator __pos, forward_list& __list)
 443       { splice_after(__pos, std::move(__list)); }
 444
 445       void
 446       splice_after(const_iterator __pos, forward_list&& __list,
 447                    const_iterator __i)
 448       {
 449         __glibcxx_check_insert_after(__pos);
 450         _GLIBCXX_DEBUG_VERIFY(__i._M_before_dereferenceable(),
 451                               _M_message(__gnu_debug::__msg_splice_bad)
 452                               ._M_iterator(__i, "__i"));
 453         _GLIBCXX_DEBUG_VERIFY(__i._M_attached_to(&__list),
 454                               _M_message(__gnu_debug::__msg_splice_other)
 455                               ._M_iterator(__i, "__i")
 456                               ._M_sequence(__list, "__list"));
 457         _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
 458                               _M_message(__gnu_debug::__msg_splice_alloc)
 459                               ._M_sequence(*this)
 460                               ._M_sequence(__list, "__list"));
 461
 462         // _GLIBCXX_RESOLVE_LIB_DEFECTS
 463         // 250. splicing invalidates iterators
 464         _Base_const_iterator __next = std::next(__i.base());
 465         this->_M_transfer_from_if(__list, [__next](_Base_const_iterator __it)
 466           { return __it == __next; });
 467         _Base::splice_after(__pos.base(), std::move(__list._M_base()),
 468                             __i.base());
 469       }
 470
 471       void
 472       splice_after(const_iterator __pos, forward_list& __list,
 473                    const_iterator __i)
 474       { splice_after(__pos, std::move(__list), __i); }
 475
 476       void
 477       splice_after(const_iterator __pos, forward_list&& __list,
 478                    const_iterator __before, const_iterator __last)
 479       {
 480         __glibcxx_check_insert_after(__pos);
 481         __glibcxx_check_valid_range(__before, __last);
 482         _GLIBCXX_DEBUG_VERIFY(__before._M_attached_to(&__list),
 483                               _M_message(__gnu_debug::__msg_splice_other)
 484                               ._M_sequence(__list, "list")
 485                               ._M_iterator(__before, "before"));
 486         _GLIBCXX_DEBUG_VERIFY(__before._M_dereferenceable()
 487                               || __before._M_is_before_begin(),
 488                               _M_message(__gnu_debug::__msg_valid_range2)
 489                               ._M_sequence(__list, "list")
 490                               ._M_iterator(__before, "before")
 491                               ._M_iterator(__last, "last"));
 492         _GLIBCXX_DEBUG_VERIFY(__before != __last,
 493                               _M_message(__gnu_debug::__msg_valid_range2)
 494                               ._M_sequence(__list, "list")
 495                               ._M_iterator(__before, "before")
 496                               ._M_iterator(__last, "last"));
 497         _GLIBCXX_DEBUG_VERIFY(__list.get_allocator() == this->get_allocator(),
 498                               _M_message(__gnu_debug::__msg_splice_alloc)
 499                               ._M_sequence(*this)
 500                               ._M_sequence(__list, "__list"));
 501
 502         for (_Base_const_iterator __tmp = std::next(__before.base());
 503              __tmp != __last.base(); ++__tmp)
 504           {
 505             _GLIBCXX_DEBUG_VERIFY(__tmp != __list._M_base().end(),
 506                                   _M_message(__gnu_debug::__msg_valid_range2)
 507                                   ._M_sequence(__list, "list")
 508                                   ._M_iterator(__before, "before")
 509                                   ._M_iterator(__last, "last"));
 510             _GLIBCXX_DEBUG_VERIFY(&__list != this || __tmp != __pos.base(),
 511                                   _M_message(__gnu_debug::__msg_splice_overlap)
 512                                   ._M_iterator(__tmp, "position")
 513                                   ._M_iterator(__before, "before")
 514                                   ._M_iterator(__last, "last"));
 515             // _GLIBCXX_RESOLVE_LIB_DEFECTS
 516             // 250. splicing invalidates iterators
 517             this->_M_transfer_from_if(__list, [__tmp](_Base_const_iterator __it)
 518               { return __it == __tmp; });
 519           }
 520
 521         _Base::splice_after(__pos.base(), std::move(__list._M_base()),
 522                             __before.base(), __last.base());
 523       }
 524
 525       void
 526       splice_after(const_iterator __pos, forward_list& __list,
 527                    const_iterator __before, const_iterator __last)
 528       { splice_after(__pos, std::move(__list), __before, __last); }
 529
 530       void
 531       remove(const _Tp& __val)
 532       {
 533         _Base_iterator __x = _Base::before_begin();
 534         _Base_iterator __old = __x++;
 535         while (__x != _Base::end())
 536           {
 537             if (*__x == __val)
 538               __x = _M_erase_after(__old);
 539             else
 540               __old = __x++;
 541           }
 542       }
 543
 544       template<typename _Pred>
 545         void
 546         remove_if(_Pred __pred)
 547         {
 548           _Base_iterator __x = _Base::before_begin();
 549           _Base_iterator __old = __x++;
 550           while (__x != _Base::end())
 551             {
 552               if (__pred(*__x))
 553                 __x = _M_erase_after(__old);
 554               else
 555                 __old = __x++;
 556             }
 557         }
 558
 559       void
 560       unique()
 561       {
 562         _Base_iterator __first = _Base::begin();
 563         _Base_iterator __last = _Base::end();
 564         if (__first == __last)
 565           return;
 566         _Base_iterator __next = std::next(__first);
 567         while (__next != __last)
 568           {
 569             if (*__first == *__next)
 570               __next = _M_erase_after(__first);
 571             else
 572               __first = __next++;
 573           }
 574       }
 575
 576       template<typename _BinPred>
 577         void
 578         unique(_BinPred __binary_pred)
 579         {
 580           _Base_iterator __first = _Base::begin();
 581           _Base_iterator __last = _Base::end();
 582           if (__first == __last)
 583             return;
 584           _Base_iterator __next = std::next(__first);
 585           while (__next != __last)
 586             {
 587               if (__binary_pred(*__first, *__next))
 588                 __next = _M_erase_after(__first);
 589               else
 590                 __first = __next++;
 591             }
 592         }
 593
 594       void
 595       merge(forward_list&& __list)
 596       {
 597         if (this != &__list)
 598         {
 599           __glibcxx_check_sorted(_Base::begin(), _Base::end());
 600           __glibcxx_check_sorted(__list._M_base().begin(),
 601                                  __list._M_base().end());
 602           this->_M_transfer_from_if(__list, [&__list](_Base_const_iterator __it)
 603             {
 604               return __it != __list._M_base().cbefore_begin()
 605                      && __it != __list._M_base().cend();
 606             });
 607           _Base::merge(std::move(__list._M_base()));
 608         }
 609       }
 610
 611       void
 612       merge(forward_list& __list)
 613       { merge(std::move(__list)); }
 614
 615       template<typename _Comp>
 616         void
 617         merge(forward_list&& __list, _Comp __comp)
 618         {
 619           if (this != &__list)
 620           {
 621             __glibcxx_check_sorted_pred(_Base::begin(), _Base::end(), __comp);
 622             __glibcxx_check_sorted_pred(__list._M_base().begin(),
 623                                         __list._M_base().end(), __comp);
 624             this->_M_transfer_from_if(__list,
 625                                       [&__list](_Base_const_iterator __it)
 626               {
 627                 return __it != __list._M_base().cbefore_begin()
 628                        && __it != __list._M_base().cend();
 629               });
 630             _Base::merge(std::move(__list._M_base()), __comp);
 631           }
 632         }
 633
 634       template<typename _Comp>
 635         void
 636         merge(forward_list& __list, _Comp __comp)
 637         { merge(std::move(__list), __comp); }
 638
 639       using _Base::sort;
 640       using _Base::reverse;
 641
 642       _Base&
 643       _M_base() noexcept       { return *this; }
 644
 645       const _Base&
 646       _M_base() const noexcept { return *this; }
 647
 648     private:
 649       void
 650       _M_invalidate_all()
 651       {
 652         this->_M_invalidate_if([this](_Base_const_iterator __it)
 653           {
 654             return __it != this->_M_base().cbefore_begin()
 655                    && __it != this->_M_base().cend();
 656           });
 657       }
 658       typedef __gnu_debug::_Safe_iterator_base _Safe_iterator_base;
 659       static void
 660       _M_swap_aux(forward_list& __lhs,
 661                   _Safe_iterator_base*& __lhs_iterators,
 662                   forward_list& __rhs,
 663                   _Safe_iterator_base*& __rhs_iterators);
 664       void _M_swap(forward_list& __list);
 665     };
 666
 667    template<typename _Tp, typename _Alloc>
 668     void
 669     forward_list<_Tp, _Alloc>::
 670     _M_swap_aux(forward_list<_Tp, _Alloc>& __lhs,
 671                 __gnu_debug::_Safe_iterator_base*& __lhs_iterators,
 672                 forward_list<_Tp, _Alloc>& __rhs,
 673                 __gnu_debug::_Safe_iterator_base*& __rhs_iterators)
 674     {
 675       using __gnu_debug::_Safe_iterator_base;
 676       _Safe_iterator_base* __bbegin_its = 0;
 677       _Safe_iterator_base* __last_bbegin = 0;
 678       for (_Safe_iterator_base* __iter = __lhs_iterators; __iter;)
 679         {
 680           // Even iterator are casted to const_iterator, not a problem.
 681           const_iterator* __victim = static_cast<const_iterator*>(__iter);
 682           __iter = __iter->_M_next;
 683           if (__victim->base() == __rhs._M_base().cbefore_begin())
 684             {
 685               __victim->_M_unlink();
 686               if (__lhs_iterators == __victim)
 687                 __lhs_iterators = __victim->_M_next;
 688               if (__bbegin_its)
 689                 {
 690                   __victim->_M_next = __bbegin_its;
 691                   __bbegin_its->_M_prior = __victim;
 692                 }
 693               else
 694                 __last_bbegin = __victim;
 695               __bbegin_its = __victim;
 696             }
 697           else
 698             __victim->_M_sequence = &__lhs;
 699         }
 700
 701       if (__bbegin_its)
 702         {
 703           if (__rhs_iterators)
 704             {
 705               __rhs_iterators->_M_prior = __last_bbegin;
 706               __last_bbegin->_M_next = __rhs_iterators;
 707             }
 708           __rhs_iterators = __bbegin_its;
 709         }
 710     }
 711
 712   /* Special forward_list _M_swap version that do not swap the
 713    * before-begin ownership.*/
 714   template<typename _Tp, typename _Alloc>
 715     void
 716     forward_list<_Tp, _Alloc>::
 717     _M_swap(forward_list<_Tp, _Alloc>& __list)
 718     {
 719       __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
 720       std::swap(this->_M_iterators, __list._M_iterators);
 721       std::swap(this->_M_const_iterators, __list._M_const_iterators);
 722       // Useless, always 1 on forward_list
 723       //std::swap(this->_M_version, __list._M_version);
 724       _Safe_iterator_base* __this_its = this->_M_iterators;
 725       _M_swap_aux(__list, __list._M_iterators, *this, this->_M_iterators);
 726       _Safe_iterator_base* __this_const_its = this->_M_const_iterators;
 727       _M_swap_aux(__list, __list._M_const_iterators, *this,
 728                   this->_M_const_iterators);
 729       _M_swap_aux(*this, __this_its, __list, __list._M_iterators);
 730       _M_swap_aux(*this, __this_const_its, __list, __list._M_const_iterators);
 731     }
 732
 733   template<typename _Tp, typename _Alloc>
 734     bool
 735     operator==(const forward_list<_Tp, _Alloc>& __lx,
 736                const forward_list<_Tp, _Alloc>& __ly)
 737     { return __lx._M_base() == __ly._M_base(); }
 738
 739   template<typename _Tp, typename _Alloc>
 740     inline bool
 741     operator<(const forward_list<_Tp, _Alloc>& __lx,
 742               const forward_list<_Tp, _Alloc>& __ly)
 743     { return __lx._M_base() < __ly._M_base(); }
 744
 745   template<typename _Tp, typename _Alloc>
 746     inline bool
 747     operator!=(const forward_list<_Tp, _Alloc>& __lx,
 748                const forward_list<_Tp, _Alloc>& __ly)
 749     { return !(__lx == __ly); }
 750
 751   /// Based on operator<
 752   template<typename _Tp, typename _Alloc>
 753     inline bool
 754     operator>(const forward_list<_Tp, _Alloc>& __lx,
 755               const forward_list<_Tp, _Alloc>& __ly)
 756     { return (__ly < __lx); }
 757
 758   /// Based on operator<
 759   template<typename _Tp, typename _Alloc>
 760     inline bool
 761     operator>=(const forward_list<_Tp, _Alloc>& __lx,
 762                const forward_list<_Tp, _Alloc>& __ly)
 763     { return !(__lx < __ly); }
 764
 765   /// Based on operator<
 766   template<typename _Tp, typename _Alloc>
 767     inline bool
 768     operator<=(const forward_list<_Tp, _Alloc>& __lx,
 769                const forward_list<_Tp, _Alloc>& __ly)
 770     { return !(__ly < __lx); }
 771
 772   /// See std::forward_list::swap().
 773   template<typename _Tp, typename _Alloc>
 774     inline void
 775     swap(forward_list<_Tp, _Alloc>& __lx,
 776          forward_list<_Tp, _Alloc>& __ly)
 777     { __lx.swap(__ly); }
 778
 779 } // namespace __debug
 780 } // namespace std
 781
 782 namespace __gnu_debug
 783 {
 784   template<class _Tp, class _Alloc>
 785     struct _BeforeBeginHelper<std::__debug::forward_list<_Tp, _Alloc> >
 786     {
 787       typedef std::__debug::forward_list<_Tp, _Alloc> _Sequence;
 788
 789       template<typename _Iterator>
 790         static bool
 791         _S_Is(const _Safe_iterator<_Iterator, _Sequence>& __it)
 792         {
 793           return
 794             __it.base() == __it._M_get_sequence()->_M_base().before_begin();
 795         }
 796
 797       template<typename _Iterator>
 798         static bool
 799         _S_Is_Beginnest(const _Safe_iterator<_Iterator, _Sequence>& __it)
 800         { return _S_Is(__it); }
 801     };
 802
 803 #ifndef _GLIBCXX_DEBUG_PEDANTIC
 804   template<class _Tp, class _Alloc>
 805     struct _Insert_range_from_self_is_safe<
 806       std::__debug::forward_list<_Tp, _Alloc> >
 807     { enum { __value = 1 }; };
 808 #endif
 809 }
 810
 811 #endif