1 // <forward_list.tcc> -*- C++ -*-
3 // Copyright (C) 2008-2024 Free Software Foundation, Inc.
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)
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.
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.
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/>.
25 /** @file bits/forward_list.tcc
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{forward_list}
30 #ifndef _FORWARD_LIST_TCC
31 #define _FORWARD_LIST_TCC 1
33 namespace std _GLIBCXX_VISIBILITY(default)
35 _GLIBCXX_BEGIN_NAMESPACE_VERSION
36 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
38 template<typename _Tp, typename _Alloc>
39 _Fwd_list_base<_Tp, _Alloc>::
40 _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a)
41 : _M_impl(std::move(__a))
43 if (__lst._M_get_Node_allocator() == _M_get_Node_allocator())
44 this->_M_impl._M_head = std::move(__lst._M_impl._M_head);
47 template<typename _Tp, typename _Alloc>
48 template<typename... _Args>
50 _Fwd_list_base<_Tp, _Alloc>::
51 _M_insert_after(const_iterator __pos, _Args&&... __args)
53 _Fwd_list_node_base* __to
54 = const_cast<_Fwd_list_node_base*>(__pos._M_node);
55 _Node* __thing = _M_create_node(std::forward<_Args>(__args)...);
56 __thing->_M_next = __to->_M_next;
57 __to->_M_next = __thing;
61 template<typename _Tp, typename _Alloc>
63 _Fwd_list_base<_Tp, _Alloc>::
64 _M_erase_after(_Fwd_list_node_base* __pos)
66 _Node* __curr = static_cast<_Node*>(__pos->_M_next);
67 __pos->_M_next = __curr->_M_next;
68 _Node_alloc_traits::destroy(_M_get_Node_allocator(),
72 return __pos->_M_next;
75 template<typename _Tp, typename _Alloc>
77 _Fwd_list_base<_Tp, _Alloc>::
78 _M_erase_after(_Fwd_list_node_base* __pos,
79 _Fwd_list_node_base* __last)
81 _Node* __curr = static_cast<_Node*>(__pos->_M_next);
82 while (__curr != __last)
84 _Node* __temp = __curr;
85 __curr = static_cast<_Node*>(__curr->_M_next);
86 _Node_alloc_traits::destroy(_M_get_Node_allocator(),
91 __pos->_M_next = __last;
95 // Called by the range constructor to implement [23.3.4.2]/9
96 template<typename _Tp, typename _Alloc>
97 template<typename _InputIterator>
99 forward_list<_Tp, _Alloc>::
100 _M_range_initialize(_InputIterator __first, _InputIterator __last)
102 _Node_base* __to = &this->_M_impl._M_head;
103 for (; __first != __last; ++__first)
105 __to->_M_next = this->_M_create_node(*__first);
106 __to = __to->_M_next;
110 // Called by forward_list(n,v,a).
111 template<typename _Tp, typename _Alloc>
113 forward_list<_Tp, _Alloc>::
114 _M_fill_initialize(size_type __n, const value_type& __value)
116 _Node_base* __to = &this->_M_impl._M_head;
119 __to->_M_next = this->_M_create_node(__value);
120 __to = __to->_M_next;
124 template<typename _Tp, typename _Alloc>
126 forward_list<_Tp, _Alloc>::
127 _M_default_initialize(size_type __n)
129 _Node_base* __to = &this->_M_impl._M_head;
132 __to->_M_next = this->_M_create_node();
133 __to = __to->_M_next;
137 template<typename _Tp, typename _Alloc>
138 forward_list<_Tp, _Alloc>&
139 forward_list<_Tp, _Alloc>::
140 operator=(const forward_list& __list)
142 if (std::__addressof(__list) != this)
144 if (_Node_alloc_traits::_S_propagate_on_copy_assign())
146 auto& __this_alloc = this->_M_get_Node_allocator();
147 auto& __that_alloc = __list._M_get_Node_allocator();
148 if (!_Node_alloc_traits::_S_always_equal()
149 && __this_alloc != __that_alloc)
151 // replacement allocator cannot free existing storage
154 std::__alloc_on_copy(__this_alloc, __that_alloc);
156 assign(__list.cbegin(), __list.cend());
161 template<typename _Tp, typename _Alloc>
163 forward_list<_Tp, _Alloc>::
164 _M_default_insert_after(const_iterator __pos, size_type __n)
166 const_iterator __saved_pos = __pos;
170 __pos = emplace_after(__pos);
174 erase_after(__saved_pos, ++__pos);
175 __throw_exception_again;
179 template<typename _Tp, typename _Alloc>
181 forward_list<_Tp, _Alloc>::
182 resize(size_type __sz)
184 iterator __k = before_begin();
187 while (__k._M_next() != end() && __len < __sz)
193 erase_after(__k, end());
195 _M_default_insert_after(__k, __sz - __len);
198 template<typename _Tp, typename _Alloc>
200 forward_list<_Tp, _Alloc>::
201 resize(size_type __sz, const value_type& __val)
203 iterator __k = before_begin();
206 while (__k._M_next() != end() && __len < __sz)
212 erase_after(__k, end());
214 insert_after(__k, __sz - __len, __val);
217 template<typename _Tp, typename _Alloc>
218 typename forward_list<_Tp, _Alloc>::iterator
219 forward_list<_Tp, _Alloc>::
220 _M_splice_after(const_iterator __pos,
221 const_iterator __before, const_iterator __last)
223 _Node_base* __tmp = const_cast<_Node_base*>(__pos._M_node);
224 _Node_base* __b = const_cast<_Node_base*>(__before._M_node);
225 _Node_base* __end = __b;
227 while (__end && __end->_M_next != __last._M_node)
228 __end = __end->_M_next;
231 return iterator(__tmp->_M_transfer_after(__b, __end));
233 return iterator(__tmp);
236 template<typename _Tp, typename _Alloc>
238 forward_list<_Tp, _Alloc>::
239 splice_after(const_iterator __pos, forward_list&&,
240 const_iterator __i) noexcept
242 const_iterator __j = __i;
245 if (__pos == __i || __pos == __j)
248 _Node_base* __tmp = const_cast<_Node_base*>(__pos._M_node);
249 __tmp->_M_transfer_after(const_cast<_Node_base*>(__i._M_node),
250 const_cast<_Node_base*>(__j._M_node));
253 template<typename _Tp, typename _Alloc>
254 typename forward_list<_Tp, _Alloc>::iterator
255 forward_list<_Tp, _Alloc>::
256 insert_after(const_iterator __pos, size_type __n, const _Tp& __val)
260 forward_list __tmp(__n, __val, get_allocator());
261 return _M_splice_after(__pos, __tmp.before_begin(), __tmp.end());
264 return iterator(const_cast<_Node_base*>(__pos._M_node));
267 template<typename _Tp, typename _Alloc>
268 template<typename _InputIterator, typename>
269 typename forward_list<_Tp, _Alloc>::iterator
270 forward_list<_Tp, _Alloc>::
271 insert_after(const_iterator __pos,
272 _InputIterator __first, _InputIterator __last)
274 forward_list __tmp(__first, __last, get_allocator());
276 return _M_splice_after(__pos, __tmp.before_begin(), __tmp.end());
278 return iterator(const_cast<_Node_base*>(__pos._M_node));
281 #if __cplusplus > 201703L
282 # define _GLIBCXX20_ONLY(__expr) __expr
284 # define _GLIBCXX20_ONLY(__expr)
287 template<typename _Tp, typename _Alloc>
289 forward_list<_Tp, _Alloc>::
290 remove(const _Tp& __val) -> __remove_return_type
292 size_type __removed __attribute__((__unused__)) = 0;
293 forward_list __to_destroy(get_allocator());
295 auto __prev_it = cbefore_begin();
296 while (_Node* __tmp = static_cast<_Node*>(__prev_it._M_node->_M_next))
297 if (*__tmp->_M_valptr() == __val)
299 __to_destroy.splice_after(__to_destroy.cbefore_begin(),
301 _GLIBCXX20_ONLY( __removed++ );
306 return _GLIBCXX20_ONLY( __removed );
309 template<typename _Tp, typename _Alloc>
310 template<typename _Pred>
312 forward_list<_Tp, _Alloc>::
313 remove_if(_Pred __pred) -> __remove_return_type
315 size_type __removed __attribute__((__unused__)) = 0;
316 forward_list __to_destroy(get_allocator());
318 auto __prev_it = cbefore_begin();
319 while (_Node* __tmp = static_cast<_Node*>(__prev_it._M_node->_M_next))
320 if (__pred(*__tmp->_M_valptr()))
322 __to_destroy.splice_after(__to_destroy.cbefore_begin(),
324 _GLIBCXX20_ONLY( __removed++ );
329 return _GLIBCXX20_ONLY( __removed );
332 template<typename _Tp, typename _Alloc>
333 template<typename _BinPred>
335 forward_list<_Tp, _Alloc>::
336 unique(_BinPred __binary_pred) -> __remove_return_type
338 iterator __first = begin();
339 iterator __last = end();
340 if (__first == __last)
341 return _GLIBCXX20_ONLY(0);
343 forward_list __to_destroy(get_allocator());
344 size_type __removed __attribute__((__unused__)) = 0;
345 iterator __next = __first;
346 while (++__next != __last)
348 if (__binary_pred(*__first, *__next))
350 __to_destroy.splice_after(__to_destroy.cbefore_begin(),
352 _GLIBCXX20_ONLY( __removed++ );
359 return _GLIBCXX20_ONLY( __removed );
362 #undef _GLIBCXX20_ONLY
364 template<typename _Tp, typename _Alloc>
365 template<typename _Comp>
367 forward_list<_Tp, _Alloc>::
368 merge(forward_list&& __list, _Comp __comp)
370 // _GLIBCXX_RESOLVE_LIB_DEFECTS
371 // 3088. forward_list::merge behavior unclear when passed *this
372 if (std::__addressof(__list) == this)
375 _Node_base* __node = &this->_M_impl._M_head;
376 while (__node->_M_next && __list._M_impl._M_head._M_next)
378 if (__comp(*static_cast<_Node*>
379 (__list._M_impl._M_head._M_next)->_M_valptr(),
381 (__node->_M_next)->_M_valptr()))
382 __node->_M_transfer_after(&__list._M_impl._M_head,
383 __list._M_impl._M_head._M_next);
384 __node = __node->_M_next;
387 if (__list._M_impl._M_head._M_next)
388 *__node = std::move(__list._M_impl._M_head);
391 template<typename _Tp, typename _Alloc>
393 operator==(const forward_list<_Tp, _Alloc>& __lx,
394 const forward_list<_Tp, _Alloc>& __ly)
396 // We don't have size() so we need to walk through both lists
397 // making sure both iterators are valid.
398 auto __ix = __lx.cbegin();
399 auto __iy = __ly.cbegin();
400 while (__ix != __lx.cend() && __iy != __ly.cend())
402 if (!(*__ix == *__iy))
407 if (__ix == __lx.cend() && __iy == __ly.cend())
413 template<typename _Tp, class _Alloc>
414 template<typename _Comp>
416 forward_list<_Tp, _Alloc>::
419 // If `next' is nullptr, return immediately.
420 _Node* __list = static_cast<_Node*>(this->_M_impl._M_head._M_next);
424 unsigned long __insize = 1;
430 _Node* __tail = nullptr;
432 // Count number of merges we do in this pass.
433 unsigned long __nmerges = 0;
438 // There exists a merge to be done.
439 // Step `insize' places along from p.
441 unsigned long __psize = 0;
442 for (unsigned long __i = 0; __i < __insize; ++__i)
445 __q = static_cast<_Node*>(__q->_M_next);
450 // If q hasn't fallen off end, we have two lists to merge.
451 unsigned long __qsize = __insize;
453 // Now we have two lists; merge them.
454 while (__psize > 0 || (__qsize > 0 && __q))
456 // Decide whether next node of merge comes from p or q.
460 // p is empty; e must come from q.
462 __q = static_cast<_Node*>(__q->_M_next);
465 else if (__qsize == 0 || !__q)
467 // q is empty; e must come from p.
469 __p = static_cast<_Node*>(__p->_M_next);
472 else if (!__comp(*__q->_M_valptr(), *__p->_M_valptr()))
474 // First node of q is not lower; e must come from p.
476 __p = static_cast<_Node*>(__p->_M_next);
481 // First node of q is lower; e must come from q.
483 __q = static_cast<_Node*>(__q->_M_next);
487 // Add the next node to the merged list.
489 __tail->_M_next = __e;
495 // Now p has stepped `insize' places along, and q has too.
498 __tail->_M_next = nullptr;
500 // If we have done only one merge, we're finished.
501 // Allow for nmerges == 0, the empty list case.
504 this->_M_impl._M_head._M_next = __list;
508 // Otherwise repeat, merging lists twice the size.
513 _GLIBCXX_END_NAMESPACE_CONTAINER
514 _GLIBCXX_END_NAMESPACE_VERSION
517 #endif /* _FORWARD_LIST_TCC */