// -*- C++ -*- // Copyright (C) 2008-2025 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // . /** @file bits/forward_list.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{forward_list} */ #ifndef _FORWARD_LIST_H #define _FORWARD_LIST_H 1 #ifdef _GLIBCXX_SYSHDR #pragma GCC system_header #endif #include #include #include #include #include #include #include #include #include #include #include #include #if __glibcxx_containers_ranges // C++ >= 23 # include // ranges::begin, ranges::distance etc. # include // ranges::subrange #endif #if ! defined _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST # define _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST 1 #endif namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION _GLIBCXX_BEGIN_NAMESPACE_CONTAINER /** * @brief A helper basic node class for %forward_list. * * This is just a linked list with nothing inside it. * There are purely list shuffling utility methods here. */ struct _Fwd_list_node_base { using _Base_ptr = _Fwd_list_node_base*; _Fwd_list_node_base() = default; _Fwd_list_node_base(_Fwd_list_node_base&& __x) noexcept : _M_next(__x._M_next) { __x._M_next = nullptr; } _Fwd_list_node_base(const _Fwd_list_node_base&) = delete; _Fwd_list_node_base& operator=(const _Fwd_list_node_base&) = delete; _Fwd_list_node_base& operator=(_Fwd_list_node_base&& __x) noexcept { _M_next = __x._M_next; __x._M_next = nullptr; return *this; } _Fwd_list_node_base* _M_next = nullptr; _Fwd_list_node_base* _M_transfer_after(_Fwd_list_node_base* __begin, _Fwd_list_node_base* __end) noexcept { _Fwd_list_node_base* __keep = __begin->_M_next; if (__end) { __begin->_M_next = __end->_M_next; __end->_M_next = _M_next; } else __begin->_M_next = nullptr; _M_next = __keep; return __end; } void _M_reverse_after() noexcept { _Fwd_list_node_base* __tail = _M_next; if (!__tail) return; while (_Fwd_list_node_base* __temp = __tail->_M_next) { _Fwd_list_node_base* __keep = _M_next; _M_next = __temp; __tail->_M_next = __temp->_M_next; _M_next->_M_next = __keep; } } _Fwd_list_node_base* _M_base_ptr() { return this; } const _Fwd_list_node_base* _M_base_ptr() const { return this; } }; /** * @brief A helper node class for %forward_list. * This is just a linked list with uninitialized storage for a * data value in each node. * There is a sorting utility method. */ template struct _Fwd_list_node : public _Fwd_list_node_base { using _Node_ptr = _Fwd_list_node*; _Fwd_list_node() = default; __gnu_cxx::__aligned_buffer<_Tp> _M_storage; _Tp* _M_valptr() noexcept { return _M_storage._M_ptr(); } const _Tp* _M_valptr() const noexcept { return _M_storage._M_ptr(); } _Node_ptr _M_node_ptr() { return this; } }; template struct _Fwd_list_const_iterator; /** * @brief A forward_list::iterator. * * All the functions are op overloads. */ template struct _Fwd_list_iterator { typedef _Fwd_list_iterator<_Tp> _Self; typedef _Fwd_list_node<_Tp> _Node; typedef _Tp value_type; typedef _Tp* pointer; typedef _Tp& reference; typedef ptrdiff_t difference_type; typedef std::forward_iterator_tag iterator_category; _Fwd_list_iterator() noexcept : _M_node() { } explicit _Fwd_list_iterator(_Fwd_list_node_base* __n) noexcept : _M_node(__n) { } [[__nodiscard__]] reference operator*() const noexcept { return *static_cast<_Node*>(this->_M_node)->_M_valptr(); } [[__nodiscard__]] pointer operator->() const noexcept { return static_cast<_Node*>(this->_M_node)->_M_valptr(); } _Self& operator++() noexcept { _M_node = _M_node->_M_next; return *this; } _Self operator++(int) noexcept { _Self __tmp(*this); _M_node = _M_node->_M_next; return __tmp; } /** * @brief Forward list iterator equality comparison. */ [[__nodiscard__]] friend bool operator==(const _Self& __x, const _Self& __y) noexcept { return __x._M_node == __y._M_node; } #if __cpp_impl_three_way_comparison < 201907L /** * @brief Forward list iterator inequality comparison. */ [[__nodiscard__]] friend bool operator!=(const _Self& __x, const _Self& __y) noexcept { return __x._M_node != __y._M_node; } #endif private: template friend class forward_list; template friend struct _Fwd_list_base; friend struct _Fwd_list_const_iterator<_Tp>; _Self _M_next() const noexcept { if (_M_node) return _Fwd_list_iterator(_M_node->_M_next); else return _Fwd_list_iterator(nullptr); } _Fwd_list_node_base* _M_node; }; /** * @brief A forward_list::const_iterator. * * All the functions are op overloads. */ template struct _Fwd_list_const_iterator { typedef _Fwd_list_const_iterator<_Tp> _Self; typedef const _Fwd_list_node<_Tp> _Node; typedef _Fwd_list_iterator<_Tp> iterator; typedef _Tp value_type; typedef const _Tp* pointer; typedef const _Tp& reference; typedef ptrdiff_t difference_type; typedef std::forward_iterator_tag iterator_category; _Fwd_list_const_iterator() noexcept : _M_node() { } explicit _Fwd_list_const_iterator(const _Fwd_list_node_base* __n) noexcept : _M_node(__n) { } _Fwd_list_const_iterator(const iterator& __iter) noexcept : _M_node(__iter._M_node) { } [[__nodiscard__]] reference operator*() const noexcept { return *static_cast<_Node*>(this->_M_node)->_M_valptr(); } [[__nodiscard__]] pointer operator->() const noexcept { return static_cast<_Node*>(this->_M_node)->_M_valptr(); } _Self& operator++() noexcept { _M_node = _M_node->_M_next; return *this; } _Self operator++(int) noexcept { _Self __tmp(*this); _M_node = _M_node->_M_next; return __tmp; } /** * @brief Forward list const_iterator equality comparison. */ [[__nodiscard__]] friend bool operator==(const _Self& __x, const _Self& __y) noexcept { return __x._M_node == __y._M_node; } #if __cpp_impl_three_way_comparison < 201907L /** * @brief Forward list const_iterator inequality comparison. */ [[__nodiscard__]] friend bool operator!=(const _Self& __x, const _Self& __y) noexcept { return __x._M_node != __y._M_node; } #endif private: template friend class forward_list; template friend struct _Fwd_list_base; _Self _M_next() const noexcept { if (this->_M_node) return _Fwd_list_const_iterator(_M_node->_M_next); else return _Fwd_list_const_iterator(nullptr); } _Fwd_list_iterator<_Tp> _M_const_cast() const noexcept { return _Fwd_list_iterator<_Tp>( const_cast<_Fwd_list_node_base*>(_M_node)); } const _Fwd_list_node_base* _M_node; }; template class forward_list; template struct _Fwd_list_base; namespace __fwdlist { #if _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST /// The node-base type for allocators that use fancy pointers. template struct _Node_base { using _Base_ptr = __ptr_rebind<_VoidPtr, _Node_base>; _Node_base() = default; _Node_base(_Node_base&& __x) noexcept : _M_next(__x._M_next) { __x._M_next = nullptr; } _Node_base(const _Node_base&) = delete; _Node_base& operator=(const _Node_base&) = delete; _Node_base& operator=(_Node_base&& __x) noexcept { _M_next = __x._M_next; __x._M_next = nullptr; return *this; } _Base_ptr _M_next = nullptr; // Splice (begin,end) before _M_next. _Base_ptr _M_transfer_after(_Base_ptr __begin, _Base_ptr __end) noexcept { _Base_ptr __keep = __begin->_M_next; if (__end) { __begin->_M_next = __end->_M_next; __end->_M_next = _M_next; } else __begin->_M_next = nullptr; _M_next = __keep; return __end; } void _M_reverse_after() noexcept { _Base_ptr __tail = _M_next; if (!__tail) return; while (_Base_ptr __temp = __tail->_M_next) { _Base_ptr __keep = _M_next; _M_next = __temp; __tail->_M_next = __temp->_M_next; _M_next->_M_next = __keep; } } // This is not const-correct, but it's only used in a const access path // by std::forward_list::empty(), where it doesn't escape, and by // std::forward_list::before_begin() const, where the pointer is used // to initialize a const_iterator and so constness is restored. _Base_ptr _M_base_ptr() const { return pointer_traits<_Base_ptr>:: pointer_to(const_cast<_Node_base&>(*this)); } }; /** * @brief A helper node class for %forward_list. */ template struct _Node : public _Node_base<__ptr_rebind<_ValPtr, void>> { using value_type = typename pointer_traits<_ValPtr>::element_type; using _Node_ptr = __ptr_rebind<_ValPtr, _Node>; _Node() noexcept { } ~_Node() { } _Node(_Node&&) = delete; union _Uninit_storage { _Uninit_storage() noexcept { } ~_Uninit_storage() { } #if ! _GLIBCXX_INLINE_VERSION // For ABI compatibility we need to overalign this member. alignas(__alignof__(value_type)) // XXX GLIBCXX_ABI Deprecated #endif value_type _M_data; }; _Uninit_storage _M_u; value_type* _M_valptr() noexcept { return std::__addressof(_M_u._M_data); } const value_type* _M_valptr() const noexcept { return std::__addressof(_M_u._M_data); } _Node_ptr _M_node_ptr() { return pointer_traits<_Node_ptr>::pointer_to(*this); } }; /// A forward_list iterator when the allocator uses fancy pointers. template class _Iterator { using _Node = __fwdlist::_Node<_Ptr>; using _Base_ptr = typename __fwdlist::_Node_base<__ptr_rebind<_Ptr, void>>::_Base_ptr; template using __maybe_const = __conditional_t<_Const, const _Tp, _Tp>; public: using value_type = typename pointer_traits<_Ptr>::element_type; using difference_type = ptrdiff_t; using iterator_category = forward_iterator_tag; using pointer = __maybe_const*; using reference = __maybe_const&; constexpr _Iterator() noexcept : _M_node() { } _Iterator(const _Iterator&) = default; _Iterator& operator=(const _Iterator&) = default; #ifdef __glibcxx_concepts constexpr _Iterator(const _Iterator& __i) requires _Const #else template> constexpr _Iterator(const _Iterator<_OtherConst, _Ptr>& __i) #endif : _M_node(__i._M_node) { } constexpr explicit _Iterator(_Base_ptr __x) noexcept : _M_node(__x) { } [[__nodiscard__]] constexpr reference operator*() const noexcept { return static_cast<_Node&>(*this->_M_node)._M_u._M_data; } [[__nodiscard__]] constexpr pointer operator->() const noexcept { return static_cast<_Node&>(*this->_M_node)._M_valptr(); } _GLIBCXX14_CONSTEXPR _Iterator& operator++() noexcept { _M_node = _M_node->_M_next; return *this; } _GLIBCXX14_CONSTEXPR _Iterator operator++(int) noexcept { _Iterator __tmp(*this); _M_node = _M_node->_M_next; return __tmp; } /** * @brief Forward list iterator equality comparison. */ [[__nodiscard__]] friend constexpr bool operator==(const _Iterator& __x, const _Iterator& __y) noexcept { return __x._M_node == __y._M_node; } #if __cpp_impl_three_way_comparison < 201907L /** * @brief Forward list iterator inequality comparison. */ [[__nodiscard__]] friend constexpr bool operator!=(const _Iterator& __x, const _Iterator& __y) noexcept { return __x._M_node != __y._M_node; } #endif private: template friend class _GLIBCXX_STD_C::forward_list; template friend struct _GLIBCXX_STD_C::_Fwd_list_base; constexpr _Iterator _M_const_cast() const noexcept { return _Iterator(_M_node); } friend _Iterator; constexpr _Iterator _M_next() const noexcept { return _Iterator(_M_node ? _M_node->_M_next : nullptr); } _Base_ptr _M_node; }; #endif // USE_ALLOC_PTR_FOR_FWD_LIST // Determine the node and iterator types used by std::forward_list. template struct _Node_traits; #if _GLIBCXX_USE_ALLOC_PTR_FOR_LIST <= 9000 // Specialization for the simple case where the allocator's pointer type // is the same type as value_type*. // For ABI compatibility we can't change the types used for this case. template struct _Node_traits<_Tp, _Tp*> { using _Node_base = _Fwd_list_node_base; using _Node = _Fwd_list_node<_Tp>; using _Iterator = _Fwd_list_iterator<_Tp>; using _Const_iterator = _Fwd_list_const_iterator<_Tp>; }; #endif #if ! _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST // Always use the T* specialization. template struct _Node_traits : _Node_traits<_Tp, _Tp*> { }; #else // Primary template used when the allocator uses fancy pointers. template struct _Node_traits { private: using _VoidPtr = __ptr_rebind<_Ptr, void>; using _ValPtr = __ptr_rebind<_Ptr, _Tp>; public: using _Node_base = __fwdlist::_Node_base<_VoidPtr>; using _Node = __fwdlist::_Node<_ValPtr>; using _Iterator = __fwdlist::_Iterator; using _Const_iterator = __fwdlist::_Iterator; }; #endif // USE_ALLOC_PTR_FOR_FWD_LIST } // namespace __fwdlist /** * @brief Base class for %forward_list. */ template struct _Fwd_list_base { #if __cplusplus > 201703L || defined __STRICT_ANSI__ // The static_assert in forward_list ensures _Alloc::value_type is _Tp. using pointer = typename allocator_traits<_Alloc>::pointer; #else using _Tp_alloc_traits = typename allocator_traits<_Alloc>::template rebind_traits<_Tp>; using pointer = typename _Tp_alloc_traits::pointer; #endif protected: using _Node_traits = __fwdlist::_Node_traits<_Tp, pointer>; using _Node = typename _Node_traits::_Node; using _Node_alloc_type = __alloc_rebind<_Alloc, _Node>; using _Node_alloc_traits = __gnu_cxx::__alloc_traits<_Node_alloc_type>; using _Node_ptr = typename _Node_alloc_traits::pointer; using _Base_ptr = typename _Node_traits::_Node_base::_Base_ptr; struct _Fwd_list_impl : public _Node_alloc_type { typename _Node_traits::_Node_base _M_head; _Fwd_list_impl() noexcept(is_nothrow_default_constructible<_Node_alloc_type>::value) : _Node_alloc_type(), _M_head() { } _Fwd_list_impl(_Fwd_list_impl&&) = default; _Fwd_list_impl(_Fwd_list_impl&& __fl, _Node_alloc_type&& __a) : _Node_alloc_type(std::move(__a)), _M_head(std::move(__fl._M_head)) { } _Fwd_list_impl(_Node_alloc_type&& __a) : _Node_alloc_type(std::move(__a)), _M_head() { } }; _Fwd_list_impl _M_impl; public: using iterator = typename _Node_traits::_Iterator; using const_iterator = typename _Node_traits::_Const_iterator; _Node_alloc_type& _M_get_Node_allocator() noexcept { return this->_M_impl; } const _Node_alloc_type& _M_get_Node_allocator() const noexcept { return this->_M_impl; } _Fwd_list_base() = default; _Fwd_list_base(_Node_alloc_type&& __a) : _M_impl(std::move(__a)) { } // When allocators are always equal. _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a, std::true_type) : _M_impl(std::move(__lst._M_impl), std::move(__a)) { } // When allocators are not always equal. _Fwd_list_base(_Fwd_list_base&& __lst, _Node_alloc_type&& __a); _Fwd_list_base(_Fwd_list_base&&) = default; ~_Fwd_list_base() { _M_erase_after(_M_impl._M_head._M_base_ptr(), nullptr); } protected: #if ! _GLIBCXX_INLINE_VERSION // XXX GLIBCXX_ABI Deprecated _Node* _M_get_node() { auto __ptr = _Node_alloc_traits::allocate(_M_get_Node_allocator(), 1); return std::__to_address(__ptr); } #endif void _M_put_node(_Node_ptr __p) { #if _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST _Node_alloc_traits::deallocate(_M_get_Node_allocator(), __p, 1); #else typedef typename _Node_alloc_traits::pointer _Ptr; auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__p); _Node_alloc_traits::deallocate(_M_get_Node_allocator(), __ptr, 1); #endif } template _Node_ptr _M_create_node(_Args&&... __args) { auto& __alloc = _M_get_Node_allocator(); auto __guard = std::__allocate_guarded_obj(__alloc); _Node_alloc_traits::construct(__alloc, __guard->_M_valptr(), std::forward<_Args>(__args)...); auto __p = __guard.release(); #if _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST return __p; #else return std::__to_address(__p); #endif } #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr void _M_destroy_node(_Node_ptr __p) { auto& __alloc = _M_get_Node_allocator(); // Destroy the element _Node_alloc_traits::destroy(__alloc, __p->_M_valptr()); // Only destroy the node if the pointers require it. if constexpr (!is_trivially_destructible<_Base_ptr>::value) __p->~_Node(); _M_put_node(__p); } #pragma GCC diagnostic pop template _Base_ptr _M_insert_after(const_iterator __pos, _Args&&... __args); _Base_ptr _M_erase_after(_Base_ptr __pos); _Base_ptr _M_erase_after(_Base_ptr __pos, _Base_ptr __last); }; /** * @brief A standard container with linear time access to elements, * and fixed time insertion/deletion at any point in the sequence. * * @ingroup sequences * @headerfile forward_list * @since C++11 * * @tparam _Tp Type of element. * @tparam _Alloc Allocator type, defaults to allocator<_Tp>. * * Meets the requirements of a container, a * sequence, including the * optional sequence requirements with the * %exception of `at` and `operator[]`. * * This is a @e singly @e linked %list. Traversal up the * %list requires linear time, but adding and removing elements (or * @e nodes) is done in constant time, regardless of where the * change takes place. Unlike std::vector and std::deque, * random-access iterators are not provided, so subscripting (`[]`) * access is not allowed. For algorithms which only need * sequential access, this lack makes no difference. * * Also unlike the other standard containers, std::forward_list provides * specialized algorithms %unique to linked lists, such as * splicing, sorting, and in-place reversal. */ template> class forward_list : private _Fwd_list_base<_Tp, _Alloc> { static_assert(is_same::type, _Tp>::value, "std::forward_list must have a non-const, non-volatile value_type"); #if __cplusplus > 201703L || defined __STRICT_ANSI__ static_assert(is_same::value, "std::forward_list must have the same value_type as its allocator"); #endif private: typedef _Fwd_list_base<_Tp, _Alloc> _Base; typedef _Fwd_list_node_base _Node_base; typedef typename _Base::_Node _Node; typedef typename _Base::_Node_alloc_type _Node_alloc_type; typedef typename _Base::_Node_alloc_traits _Node_alloc_traits; typedef allocator_traits<__alloc_rebind<_Alloc, _Tp>> _Alloc_traits; public: // types: typedef _Tp value_type; typedef typename _Alloc_traits::pointer pointer; typedef typename _Alloc_traits::const_pointer const_pointer; typedef value_type& reference; typedef const value_type& const_reference; typedef typename _Base::iterator iterator; typedef typename _Base::const_iterator const_iterator; typedef std::size_t size_type; typedef std::ptrdiff_t difference_type; typedef _Alloc allocator_type; // 23.3.4.2 construct/copy/destroy: /** * @brief Creates a %forward_list with no elements. */ forward_list() = default; /** * @brief Creates a %forward_list with no elements. * @param __al An allocator object. */ explicit forward_list(const _Alloc& __al) noexcept : _Base(_Node_alloc_type(__al)) { } /** * @brief Copy constructor with allocator argument. * @param __list Input list to copy. * @param __al An allocator object. */ forward_list(const forward_list& __list, const __type_identity_t<_Alloc>& __al) : _Base(_Node_alloc_type(__al)) { _M_range_initialize(__list.begin(), __list.end()); } private: forward_list(forward_list&& __list, _Node_alloc_type&& __al, false_type) : _Base(std::move(__list), std::move(__al)) { // If __list is not empty it means its allocator is not equal to __a, // so we need to move from each element individually. insert_after(cbefore_begin(), std::__make_move_if_noexcept_iterator(__list.begin()), std::__make_move_if_noexcept_iterator(__list.end())); } forward_list(forward_list&& __list, _Node_alloc_type&& __al, true_type) noexcept : _Base(std::move(__list), _Node_alloc_type(__al), true_type{}) { } public: /** * @brief Move constructor with allocator argument. * @param __list Input list to move. * @param __al An allocator object. */ forward_list(forward_list&& __list, const __type_identity_t<_Alloc>& __al) noexcept(_Node_alloc_traits::_S_always_equal()) : forward_list(std::move(__list), _Node_alloc_type(__al), typename _Node_alloc_traits::is_always_equal{}) { } /** * @brief Creates a %forward_list with default constructed elements. * @param __n The number of elements to initially create. * @param __al An allocator object. * * This constructor creates the %forward_list with `__n` default * constructed elements. */ explicit forward_list(size_type __n, const _Alloc& __al = _Alloc()) : _Base(_Node_alloc_type(__al)) { _M_default_initialize(__n); } /** * @brief Creates a %forward_list with copies of an exemplar element. * @param __n The number of elements to initially create. * @param __value An element to copy. * @param __al An allocator object. * * This constructor fills the %forward_list with `__n` copies of * `__value`. */ forward_list(size_type __n, const _Tp& __value, const _Alloc& __al = _Alloc()) : _Base(_Node_alloc_type(__al)) { _M_fill_initialize(__n, __value); } /** * @brief Builds a %forward_list from a range. * @param __first An input iterator. * @param __last An input iterator. * @param __al An allocator object. * * Create a %forward_list consisting of copies of the elements from * `[__first,__last)`. This is linear in N (where N is * `distance(__first,__last)`). */ template> forward_list(_InputIterator __first, _InputIterator __last, const _Alloc& __al = _Alloc()) : _Base(_Node_alloc_type(__al)) { _M_range_initialize(__first, __last); } #if __glibcxx_containers_ranges // C++ >= 23 /** * @brief Construct a forward_list from a range. * @param __rg An input range with elements that are convertible to * the forward_list's value_type. * @param __a An allocator. * * @since C++23 */ template<__detail::__container_compatible_range<_Tp> _Rg> forward_list(from_range_t, _Rg&& __rg, const _Alloc& __a = _Alloc()) : _Base(_Node_alloc_type(__a)) { auto __to = this->_M_impl._M_head._M_base_ptr(); auto __first = ranges::begin(__rg); const auto __last = ranges::end(__rg); for (; __first != __last; ++__first) { __to->_M_next = this->_M_create_node(*__first)->_M_base_ptr(); __to = __to->_M_next; } } #endif // containers_ranges /** * @brief The %forward_list copy constructor. * @param __list A %forward_list of identical element and allocator * types. */ forward_list(const forward_list& __list) : _Base(_Node_alloc_traits::_S_select_on_copy( __list._M_get_Node_allocator())) { _M_range_initialize(__list.begin(), __list.end()); } /** * @brief The %forward_list move constructor. * @param __list A %forward_list of identical element and allocator * types. * * The newly-created %forward_list contains the exact contents of the * moved instance. The contents of the moved instance are a valid, but * unspecified %forward_list. */ forward_list(forward_list&&) = default; /** * @brief Builds a %forward_list from an initializer_list * @param __il An initializer_list of value_type. * @param __al An allocator object. * * Create a %forward_list consisting of copies of the elements * in the initializer_list `__il`. This is linear in `__il.size()`. */ forward_list(std::initializer_list<_Tp> __il, const _Alloc& __al = _Alloc()) : _Base(_Node_alloc_type(__al)) { _M_range_initialize(__il.begin(), __il.end()); } /** * @brief The forward_list dtor. */ ~forward_list() noexcept { } /** * @brief The %forward_list assignment operator. * @param __list A %forward_list of identical element and allocator * types. * * All the elements of `__list` are copied. * * Whether the allocator is copied depends on the allocator traits. */ forward_list& operator=(const forward_list& __list); #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr /** * @brief The %forward_list move assignment operator. * @param __list A %forward_list of identical element and allocator * types. * * The contents of `__list` are moved into this %forward_list * (without copying, if the allocators permit it). * * Afterwards @a __list is a valid, but unspecified %forward_list * * Whether the allocator is moved depends on the allocator traits. */ forward_list& operator=(forward_list&& __list) noexcept(_Node_alloc_traits::_S_nothrow_move()) { constexpr bool __move_storage = _Node_alloc_traits::_S_propagate_on_move_assign() || _Node_alloc_traits::_S_always_equal(); if constexpr (!__move_storage) { if (__list._M_get_Node_allocator() != this->_M_get_Node_allocator()) { // The rvalue's allocator cannot be moved, or is not equal, // so we need to individually move each element. this->assign(std::make_move_iterator(__list.begin()), std::make_move_iterator(__list.end())); return *this; } } clear(); this->_M_impl._M_head._M_next = __list._M_impl._M_head._M_next; __list._M_impl._M_head._M_next = nullptr; if constexpr (_Node_alloc_traits::_S_propagate_on_move_assign()) this->_M_get_Node_allocator() = std::move(__list._M_get_Node_allocator()); return *this; } /** * @brief The %forward_list initializer list assignment operator. * @param __il An initializer_list of value_type. * * Replace the contents of the %forward_list with copies of the * elements in the initializer_list `__il`. This is linear in * `__il.size()`. */ forward_list& operator=(std::initializer_list<_Tp> __il) { assign(__il); return *this; } /** * @brief Assigns a range to a %forward_list. * @param __first An input iterator. * @param __last An input iterator. * * This function fills a %forward_list with copies of the elements * in the range `[ __first,__last)`. * * Note that the assignment completely changes the %forward_list and * that the number of elements of the resulting %forward_list is the * same as the number of elements assigned. */ template> void assign(_InputIterator __first, _InputIterator __last) { if constexpr (is_assignable<_Tp&, decltype(*__first)>::value) { auto __prev = before_begin(); auto __curr = begin(); auto __end = end(); while (__curr != __end && __first != __last) { *__curr = *__first; ++__prev; ++__curr; ++__first; } if (__first != __last) insert_after(__prev, __first, __last); else if (__curr != __end) erase_after(__prev, __end); } else { clear(); insert_after(cbefore_begin(), __first, __last); } } #pragma GCC diagnostic pop #if __glibcxx_containers_ranges // C++ >= 23 /** * @brief Assign a range to a forward_list. * @since C++23 */ template<__detail::__container_compatible_range<_Tp> _Rg> void assign_range(_Rg&& __rg) { static_assert(assignable_from<_Tp&, ranges::range_reference_t<_Rg>>); auto __first = ranges::begin(__rg); const auto __last = ranges::end(__rg); iterator __prev = before_begin(); iterator __curr = begin(); const iterator __end = end(); while (__curr != __end && __first != __last) { *__curr = *__first; __prev = __curr; ++__first; ++__curr; } if (__curr != __end) erase_after(__prev, __end); else insert_range_after(__prev, ranges::subrange(std::move(__first), __last)); } #endif // containers_ranges #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr /** * @brief Assigns a given value to a %forward_list. * @param __n Number of elements to be assigned. * @param __val Value to be assigned. * * This function fills a %forward_list with `__n` copies of the * given value. Note that the assignment completely changes the * %forward_list, and that the resulting %forward_list has `__n` * elements. */ void assign(size_type __n, const _Tp& __val) { if constexpr (is_copy_assignable<_Tp>::value) { auto __prev = before_begin(); auto __curr = begin(); auto __end = end(); while (__curr != __end && __n > 0) { *__curr = __val; ++__prev; ++__curr; --__n; } if (__n > 0) insert_after(__prev, __n, __val); else if (__curr != __end) erase_after(__prev, __end); } else { clear(); insert_after(cbefore_begin(), __n, __val); } } #pragma GCC diagnostic pop /** * @brief Assigns an initializer_list to a %forward_list. * @param __il An initializer_list of value_type. * * Replace the contents of the %forward_list with copies of the * elements in the initializer_list `__il`. This is linear in * `__il.size()`. */ void assign(std::initializer_list<_Tp> __il) { assign(__il.begin(), __il.end()); } /// Get a copy of the memory allocation object. allocator_type get_allocator() const noexcept { return allocator_type(this->_M_get_Node_allocator()); } // 23.3.4.3 iterators: /** * Returns a read/write iterator that points before the first element * in the %forward_list. Iteration is done in ordinary element order. */ [[__nodiscard__]] iterator before_begin() noexcept { return iterator(this->_M_impl._M_head._M_base_ptr()); } /** * Returns a read-only (constant) iterator that points before the * first element in the %forward_list. Iteration is done in ordinary * element order. */ [[__nodiscard__]] const_iterator before_begin() const noexcept { return const_iterator(this->_M_impl._M_head._M_base_ptr()); } /** * Returns a read/write iterator that points to the first element * in the %forward_list. Iteration is done in ordinary element order. */ [[__nodiscard__]] iterator begin() noexcept { return iterator(this->_M_impl._M_head._M_next); } /** * Returns a read-only (constant) iterator that points to the first * element in the %forward_list. Iteration is done in ordinary * element order. */ [[__nodiscard__]] const_iterator begin() const noexcept { return const_iterator(this->_M_impl._M_head._M_next); } /** * Returns a read/write iterator that points one past the last * element in the %forward_list. Iteration is done in ordinary * element order. */ [[__nodiscard__]] iterator end() noexcept { return iterator(nullptr); } /** * Returns a read-only iterator that points one past the last * element in the %forward_list. Iteration is done in ordinary * element order. */ [[__nodiscard__]] const_iterator end() const noexcept { return const_iterator(nullptr); } /** * Returns a read-only (constant) iterator that points to the * first element in the %forward_list. Iteration is done in ordinary * element order. */ [[__nodiscard__]] const_iterator cbegin() const noexcept { return const_iterator(this->_M_impl._M_head._M_next); } /** * Returns a read-only (constant) iterator that points before the * first element in the %forward_list. Iteration is done in ordinary * element order. */ [[__nodiscard__]] const_iterator cbefore_begin() const noexcept { return const_iterator(this->_M_impl._M_head._M_base_ptr()); } /** * Returns a read-only (constant) iterator that points one past * the last element in the %forward_list. Iteration is done in * ordinary element order. */ [[__nodiscard__]] const_iterator cend() const noexcept { return const_iterator(nullptr); } /** * Returns true if the %forward_list is empty. (Thus begin() would * equal end().) */ [[__nodiscard__]] bool empty() const noexcept { return this->_M_impl._M_head._M_next == nullptr; } /** * Returns the largest possible number of elements of %forward_list. */ [[__nodiscard__]] size_type max_size() const noexcept { return _Node_alloc_traits::max_size(this->_M_get_Node_allocator()); } // 23.3.4.4 element access: /** * Returns a read/write reference to the data at the first * element of the %forward_list. */ [[__nodiscard__]] reference front() { __glibcxx_requires_nonempty(); _Node& __front = static_cast<_Node&>(*this->_M_impl._M_head._M_next); return *__front._M_valptr(); } /** * Returns a read-only (constant) reference to the data at the first * element of the %forward_list. */ [[__nodiscard__]] const_reference front() const { __glibcxx_requires_nonempty(); _Node& __front = static_cast<_Node&>(*this->_M_impl._M_head._M_next); return *__front._M_valptr(); } // 23.3.4.5 modifiers: /** * @brief Constructs object in %forward_list at the front of the * list. * @param __args Arguments. * * This function will insert an object of type `Tp` constructed * with `Tp(std::forward(args)...)` at the front of the list * Due to the nature of a %forward_list this operation can * be done in constant time, and does not invalidate iterators * and references. */ template #if __cplusplus > 201402L reference #else void #endif emplace_front(_Args&&... __args) { this->_M_insert_after(cbefore_begin(), std::forward<_Args>(__args)...); #if __cplusplus > 201402L return front(); #endif } /** * @brief Add data to the front of the %forward_list. * @param __val Data to be added. * * This is a typical stack operation. The function creates an * element at the front of the %forward_list and assigns the given * data to it. Due to the nature of a %forward_list this operation * can be done in constant time, and does not invalidate iterators * and references. */ void push_front(const _Tp& __val) { this->_M_insert_after(cbefore_begin(), __val); } /** * */ void push_front(_Tp&& __val) { this->_M_insert_after(cbefore_begin(), std::move(__val)); } #if __glibcxx_containers_ranges // C++ >= 23 /** * @brief Insert a range at the beginning of a forward_list. * @param __rg An input range with elements that are convertible to * the forward_list's value_type. * * The inserted elements will be in the same order as in the range, * so they are not reversed as would happen with a simple loop calling * `emplace_front` for each element of the range. * * No iterators to existing elements are invalidated by this function. * If the insertion fails due to an exception, no elements will be added * and so the list will be unchanged. * * @since C++23 */ template<__detail::__container_compatible_range<_Tp> _Rg> void prepend_range(_Rg&& __rg) { forward_list __tmp(from_range, std::forward<_Rg>(__rg), get_allocator()); if (!__tmp.empty()) splice_after(before_begin(), __tmp); } #endif // containers_ranges /** * @brief Removes first element. * * This is a typical stack operation. It shrinks the %forward_list * by one. Due to the nature of a %forward_list this operation can * be done in constant time, and only invalidates iterators/references * to the element being removed. * * Note that no data is returned, and if the first element's data * is needed, it should be retrieved before `pop_front()` is * called. */ void pop_front() { __glibcxx_requires_nonempty(); this->_M_erase_after(this->_M_impl._M_head._M_base_ptr()); } /** * @brief Constructs object in %forward_list after the specified * iterator. * @param __pos A const_iterator into the %forward_list. * @param __args Arguments. * @return An iterator that points to the inserted data. * * This function will insert an object of type `T` constructed * with `T(std::forward(args)...)` after the specified * location. Due to the nature of a %forward_list this operation can * be done in constant time, and does not invalidate iterators * and references. */ template iterator emplace_after(const_iterator __pos, _Args&&... __args) { return iterator(this->_M_insert_after(__pos, std::forward<_Args>(__args)...)); } /** * @brief Inserts given value into %forward_list after specified * iterator. * @param __pos An iterator into the %forward_list. * @param __val Data to be inserted. * @return An iterator that points to the inserted data. * * This function will insert a copy of the given value after * the specified location. Due to the nature of a %forward_list this * operation can be done in constant time, and does not * invalidate iterators and references. */ iterator insert_after(const_iterator __pos, const _Tp& __val) { return iterator(this->_M_insert_after(__pos, __val)); } /** * */ iterator insert_after(const_iterator __pos, _Tp&& __val) { return iterator(this->_M_insert_after(__pos, std::move(__val))); } /** * @brief Inserts a number of copies of given data into the * %forward_list. * @param __pos An iterator into the %forward_list. * @param __n Number of elements to be inserted. * @param __val Data to be inserted. * @return An iterator pointing to the last inserted copy of * `val` or `pos` if `n == 0`. * * This function will insert a specified number of copies of the * given data after the location specified by `pos`. * * This operation is linear in the number of elements inserted and * does not invalidate iterators and references. */ iterator insert_after(const_iterator __pos, size_type __n, const _Tp& __val); /** * @brief Inserts a range into the %forward_list. * @param __pos An iterator into the %forward_list. * @param __first An input iterator. * @param __last An input iterator. * @return An iterator pointing to the last inserted element or * `__pos` if `__first == __last`. * * This function will insert copies of the data in the range * `[ __first, __last)` into the %forward_list after the * location specified by `__pos. * * This operation is linear in the number of elements inserted and * does not invalidate iterators and references. */ template> iterator insert_after(const_iterator __pos, _InputIterator __first, _InputIterator __last); /** * @brief Inserts the contents of an initializer_list into * %forward_list after the specified iterator. * @param __pos An iterator into the %forward_list. * @param __il An initializer_list of value_type. * @return An iterator pointing to the last inserted element * or `__pos` if `__il` is empty. * * This function will insert copies of the data in the * initializer_list `__il` into the %forward_list before the location * specified by `__pos`. * * This operation is linear in the number of elements inserted and * does not invalidate iterators and references. */ iterator insert_after(const_iterator __pos, std::initializer_list<_Tp> __il) { return insert_after(__pos, __il.begin(), __il.end()); } #if __glibcxx_containers_ranges // C++ >= 23 /** * @brief Insert a rangeinto a forward_list. * @param __position An iterator. * @param __rg An input range of elements that can be converted to * the forward_list's value type. * @return An iterator pointing to the last element inserted, * or `__position` if the range is empty. * * Inserts the elements of `__rg` after `__position`. * No iterators to existing elements are invalidated by this function. * If the insertion fails due to an exception, no elements will be added * and so the list will be unchanged. * * @since C++23 */ template<__detail::__container_compatible_range<_Tp> _Rg> iterator insert_range_after(const_iterator __position, _Rg&& __rg) { forward_list __tmp(from_range, std::forward<_Rg>(__rg), get_allocator()); return _M_splice_after(__position, __tmp.before_begin(), __tmp.end()); } #endif // containers_ranges /** * @brief Removes the element pointed to by the iterator following * `pos`. * @param __pos Iterator pointing before element to be erased. * @return An iterator pointing to the element following the one * that was erased, or `end()` if no such element exists. * * This function will erase the element at the given position and * thus shorten the %forward_list by one. * * Due to the nature of a %forward_list this operation can be done * in constant time, and only invalidates iterators/references to * the element being removed. The user is also cautioned that * this function only erases the element, and that if the element * is itself a pointer, the pointed-to memory is not touched in * any way. Managing the pointer is the user's responsibility. */ iterator erase_after(const_iterator __pos) { return iterator(this->_M_erase_after(__pos._M_const_cast()._M_node)); } /** * @brief Remove a range of elements. * @param __pos Iterator pointing before the first element to be * erased. * @param __last Iterator pointing to one past the last element to be * erased. * @return `__last` * * This function will erase the elements in the range * `(__pos,__last)` and shorten the %forward_list accordingly. * * This operation is linear time in the size of the range and only * invalidates iterators/references to the element being removed. * * The user is also cautioned that this function only erases the * elements, and that if the elements themselves are pointers, the * pointed-to memory is not touched in any way. Managing the pointer * is the user's responsibility. */ iterator erase_after(const_iterator __pos, const_iterator __last) { return iterator(this->_M_erase_after(__pos._M_const_cast()._M_node, __last._M_const_cast()._M_node)); } /** * @brief Swaps data with another %forward_list. * @param __list A %forward_list of the same element and allocator * types. * * This exchanges the elements between two lists in constant * time. Note that the global `std::swap()` function is * overloaded such that `std::swap(l1, l2)` will feed to this * function. * * Whether the allocators are swapped depends on the allocator traits. */ void swap(forward_list& __list) noexcept { std::swap(this->_M_impl._M_head._M_next, __list._M_impl._M_head._M_next); _Node_alloc_traits::_S_on_swap(this->_M_get_Node_allocator(), __list._M_get_Node_allocator()); } /** * @brief Resizes the %forward_list to the specified number of * elements. * @param __sz Number of elements the %forward_list should contain. * * This function will %resize the %forward_list to the specified * number of elements. If the number is smaller than the * %forward_list's current number of elements the %forward_list * is truncated, otherwise the %forward_list is extended and the * new elements are default constructed. */ void resize(size_type __sz); /** * @brief Resizes the %forward_list to the specified number of * elements. * @param __sz Number of elements the %forward_list should contain. * @param __val Data with which new elements should be populated. * * This function will %resize the %forward_list to the specified * number of elements. If the number is smaller than the * %forward_list's current number of elements the %forward_list * is truncated, otherwise the %forward_list is extended and new * elements are populated with given data. */ void resize(size_type __sz, const value_type& __val); /** * @brief Erases all the elements. * * Note that this function only erases * the elements, and that if the elements themselves are * pointers, the pointed-to memory is not touched in any way. * Managing the pointer is the user's responsibility. */ void clear() noexcept { this->_M_erase_after(this->_M_impl._M_head._M_base_ptr(), nullptr); } // 23.3.4.6 forward_list operations: /** * @brief Insert contents of another %forward_list. * @param __pos Iterator referencing the element to insert after. * @param __list Source list. * * The elements of `list` are inserted in constant time after * the element referenced by `pos`. `list` becomes an empty * list. * * Requires `this != &x`. */ void splice_after(const_iterator __pos, forward_list&& __list) noexcept { if (!__list.empty()) _M_splice_after(__pos, __list.before_begin(), __list.end()); } void splice_after(const_iterator __pos, forward_list& __list) noexcept { splice_after(__pos, std::move(__list)); } /** * @brief Insert element from another %forward_list. * @param __pos Iterator referencing the element to insert after. * @param __list Source list. * @param __i Iterator referencing the element before the element * to move. * * Removes the element in list `__list` referenced by `__i` and * inserts it into the current list after `__pos`. */ void splice_after(const_iterator __pos, forward_list&& __list, const_iterator __i) noexcept; void splice_after(const_iterator __pos, forward_list& __list, const_iterator __i) noexcept { splice_after(__pos, std::move(__list), __i); } /** * @brief Insert range from another %forward_list. * @param __pos Iterator referencing the element to insert after. * @param __list Source list. * @param __before Iterator referencing before the start of range * in `__list`. * @param __last Iterator referencing the end of range in `__list`. * * Removes elements in the range `(__before,__last)` and inserts them * after `__pos` in constant time. * * Undefined if `__pos` is in `(__before,__last)`. * @{ */ void splice_after(const_iterator __pos, forward_list&&, const_iterator __before, const_iterator __last) noexcept { _M_splice_after(__pos, __before, __last); } void splice_after(const_iterator __pos, forward_list&, const_iterator __before, const_iterator __last) noexcept { _M_splice_after(__pos, __before, __last); } /// @} private: #ifdef __glibcxx_list_remove_return_type // C++20 && HOSTED using __remove_return_type = size_type; # define _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG \ __attribute__((__abi_tag__("__cxx20"))) #else using __remove_return_type = void; # define _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG #endif public: /** * @brief Remove all elements equal to value. * @param __val The value to remove. * * Removes every element in the list equal to `__val`. * Remaining elements stay in list order. Note that this * function only erases the elements, and that if the elements * themselves are pointers, the pointed-to memory is not * touched in any way. Managing the pointer is the user's * responsibility. */ _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG __remove_return_type remove(const _Tp& __val); /** * @brief Remove all elements satisfying a predicate. * @param __pred Unary predicate function or object. * * Removes every element in the list for which the predicate * returns true. Remaining elements stay in list order. Note * that this function only erases the elements, and that if the * elements themselves are pointers, the pointed-to memory is * not touched in any way. Managing the pointer is the user's * responsibility. */ template __remove_return_type remove_if(_Pred __pred); /** * @brief Remove consecutive duplicate elements. * * For each consecutive set of elements with the same value, * remove all but the first one. Remaining elements stay in * list order. Note that this function only erases the * elements, and that if the elements themselves are pointers, * the pointed-to memory is not touched in any way. Managing * the pointer is the user's responsibility. */ _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG __remove_return_type unique() { return unique(std::equal_to<_Tp>()); } #undef _GLIBCXX_FWDLIST_REMOVE_RETURN_TYPE_TAG /** * @brief Remove consecutive elements satisfying a predicate. * @param __binary_pred Binary predicate function or object. * * For each consecutive set of elements [first,last) that * satisfy predicate(first,i) where i is an iterator in * [first,last), remove all but the first one. Remaining * elements stay in list order. Note that this function only * erases the elements, and that if the elements themselves are * pointers, the pointed-to memory is not touched in any way. * Managing the pointer is the user's responsibility. */ template __remove_return_type unique(_BinPred __binary_pred); /** * @brief Merge sorted lists. * @param __list Sorted list to merge. * * Assumes that both `__list` and this list are sorted according to * operator<(). Merges elements of `__list` into this list in * sorted order, leaving `__list` empty when complete. Elements in * this list precede elements in `__list` that are equal. */ void merge(forward_list&& __list) { merge(std::move(__list), std::less<_Tp>()); } void merge(forward_list& __list) { merge(std::move(__list)); } /** * @brief Merge sorted lists according to comparison function. * @param __list Sorted list to merge. * @param __comp Comparison function defining sort order. * * Assumes that both `__list` and this list are sorted according to * comp. Merges elements of `__list` into this list * in sorted order, leaving `__list` empty when complete. Elements * in this list precede elements in `__list` that are equivalent * according to comp(). */ template void merge(forward_list&& __list, _Comp __comp); template void merge(forward_list& __list, _Comp __comp) { merge(std::move(__list), __comp); } /** * @brief Sort the elements of the list. * * Sorts the elements of this list in NlogN time. Equivalent * elements remain in list order. */ void sort() { sort(std::less<_Tp>()); } /** * @brief Sort the forward_list using a comparison function. * * Sorts the elements of this list in NlogN time. Equivalent * elements remain in list order. */ template void sort(_Comp __comp); /** * @brief Reverse the elements in list. * * Reverse the order of elements in the list in linear time. */ void reverse() noexcept { this->_M_impl._M_head._M_reverse_after(); } private: // Called by the range constructor to implement [23.3.4.2]/9 template void _M_range_initialize(_InputIterator __first, _InputIterator __last); // Called by forward_list(n,v,a), and the range constructor when it // turns out to be the same thing. void _M_fill_initialize(size_type __n, const value_type& __value); // Called by splice_after and insert_after. iterator _M_splice_after(const_iterator __pos, const_iterator __before, const_iterator __last); // Called by forward_list(n). void _M_default_initialize(size_type __n); // Called by resize(sz). void _M_default_insert_after(const_iterator __pos, size_type __n); #if ! _GLIBCXX_INLINE_VERSION #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr // XXX GLIBCXX_ABI Deprecated // These members are unused by std::forward_list now, but we keep them // here so that an explicit instantiation will define them. // This ensures that explicit instantiations still define these symbols, // so that explicit instantiation declarations of std::forward_list that // were compiled with old versions of GCC can still find these symbols. // Use 'if constexpr' so that the functions don't do anything for // specializations using _Node_traits, because any // old code referencing these symbols wasn't using the fancy-pointer // specializations. void _M_move_assign(forward_list&& __list, true_type) noexcept { #if _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST if constexpr (is_same::value) #endif { clear(); this->_M_impl._M_head._M_next = __list._M_impl._M_head._M_next; __list._M_impl._M_head._M_next = nullptr; std::__alloc_on_move(this->_M_get_Node_allocator(), __list._M_get_Node_allocator()); } } void _M_move_assign(forward_list&& __list, false_type) { #if _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST if constexpr (is_same::value) #endif { if (__list._M_get_Node_allocator() == this->_M_get_Node_allocator()) _M_move_assign(std::move(__list), true_type()); else // The rvalue's allocator cannot be moved, or is not equal, // so we need to individually move each element. this->assign(std::make_move_iterator(__list.begin()), std::make_move_iterator(__list.end())); } } void _M_assign_n(size_type __n, const _Tp& __val, true_type) { #if _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST if constexpr (is_same::value) #endif { auto __prev = before_begin(); auto __curr = begin(); auto __end = end(); while (__curr != __end && __n > 0) { *__curr = __val; ++__prev; ++__curr; --__n; } if (__n > 0) insert_after(__prev, __n, __val); else if (__curr != __end) erase_after(__prev, __end); } } void _M_assign_n(size_type __n, const _Tp& __val, false_type) { #if _GLIBCXX_USE_ALLOC_PTR_FOR_FWD_LIST if constexpr (is_same::value) #endif { clear(); insert_after(cbefore_begin(), __n, __val); } } #pragma GCC diagnostic pop #endif // ! _GLIBCXX_INLINE_VERSION }; #if __cpp_deduction_guides >= 201606 template::value_type, typename _Allocator = allocator<_ValT>, typename = _RequireInputIter<_InputIterator>, typename = _RequireAllocator<_Allocator>> forward_list(_InputIterator, _InputIterator, _Allocator = _Allocator()) -> forward_list<_ValT, _Allocator>; #if __glibcxx_containers_ranges // C++ >= 23 template>> forward_list(from_range_t, _Rg&&, _Allocator = _Allocator()) -> forward_list, _Allocator>; #endif #endif /** * @brief Forward list equality comparison. * @param __lx A %forward_list * @param __ly A %forward_list of the same type as `__lx`. * @return True iff the elements of the forward lists are equal. * * This is an equivalence relation. It is linear in the number of * elements of the forward lists. Deques are considered equivalent * if corresponding elements compare equal. */ template [[__nodiscard__]] bool operator==(const forward_list<_Tp, _Alloc>& __lx, const forward_list<_Tp, _Alloc>& __ly); #if __cpp_lib_three_way_comparison /** * @brief Forward list ordering relation. * @param __x A `forward_list`. * @param __y A `forward_list` of the same type as `__x`. * @return A value indicating whether `__x` is less than, equal to, * greater than, or incomparable with `__y`. * * See `std::lexicographical_compare_three_way()` for how the determination * is made. This operator is used to synthesize relational operators like * `<` and `>=` etc. */ template [[nodiscard]] inline __detail::__synth3way_t<_Tp> operator<=>(const forward_list<_Tp, _Alloc>& __x, const forward_list<_Tp, _Alloc>& __y) { return std::lexicographical_compare_three_way(__x.begin(), __x.end(), __y.begin(), __y.end(), __detail::__synth3way); } #else /** * @brief Forward list ordering relation. * @param __lx A %forward_list. * @param __ly A %forward_list of the same type as `__lx`. * @return True iff `__lx` is lexicographically less than `__ly`. * * This is a total ordering relation. It is linear in the number of * elements of the forward lists. The elements must be comparable * with `<`. * * See std::lexicographical_compare() for how the determination is made. */ template [[__nodiscard__]] inline bool operator<(const forward_list<_Tp, _Alloc>& __lx, const forward_list<_Tp, _Alloc>& __ly) { return std::lexicographical_compare(__lx.cbegin(), __lx.cend(), __ly.cbegin(), __ly.cend()); } /// Based on operator== template [[__nodiscard__]] inline bool operator!=(const forward_list<_Tp, _Alloc>& __lx, const forward_list<_Tp, _Alloc>& __ly) { return !(__lx == __ly); } /// Based on operator< template [[__nodiscard__]] inline bool operator>(const forward_list<_Tp, _Alloc>& __lx, const forward_list<_Tp, _Alloc>& __ly) { return (__ly < __lx); } /// Based on operator< template [[__nodiscard__]] inline bool operator>=(const forward_list<_Tp, _Alloc>& __lx, const forward_list<_Tp, _Alloc>& __ly) { return !(__lx < __ly); } /// Based on operator< template [[__nodiscard__]] inline bool operator<=(const forward_list<_Tp, _Alloc>& __lx, const forward_list<_Tp, _Alloc>& __ly) { return !(__ly < __lx); } #endif // three-way comparison /// See std::forward_list::swap(). template inline void swap(forward_list<_Tp, _Alloc>& __lx, forward_list<_Tp, _Alloc>& __ly) noexcept(noexcept(__lx.swap(__ly))) { __lx.swap(__ly); } _GLIBCXX_END_NAMESPACE_CONTAINER _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #endif // _FORWARD_LIST_H