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gnu/gcc/ce6480029c2bcc78e051a02e557bcfca2ec75477/./libstdc++-v3/include/bits/forward_list.h
blob: 7b333b3b0b6e0cc455facdea9792e063a38a51db [file]
// <forward_list.h> -*- C++ -*-
// Copyright (C) 2008-2026 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
// <http://www.gnu.org/licenses/>.
/** @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 <initializer_list>
#include <bits/stl_iterator_base_types.h>
#include <bits/stl_iterator.h>
#include <bits/stl_algobase.h>
#include <bits/stl_function.h>
#include <bits/allocator.h>
#include <bits/allocated_ptr.h>
#include <bits/ptr_traits.h>
#include <debug/assertions.h>
#include <ext/alloc_traits.h>
#include <ext/aligned_buffer.h>
#include <debug/assertions.h>
#if __glibcxx_containers_ranges // C++ >= 23
# include <bits/ranges_base.h> // ranges::begin, ranges::distance etc.
# include <bits/ranges_util.h> // 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<typename _Tp>
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<typename _Tp> struct _Fwd_list_const_iterator;
/**
* @brief A forward_list::iterator.
*
* All the functions are op overloads.
*/
template<typename _Tp>
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<typename, typename>
friend class forward_list;
template<typename, typename>
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<typename _Tp>
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<typename, typename>
friend class forward_list;
template<typename, typename>
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<typename _Tp, typename _Allocator> class forward_list;
template<typename _Tp, typename _Allocator> 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<typename _VoidPtr>
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<typename _ValPtr>
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<bool _Const, typename _Ptr>
class _Iterator
{
using _Node = __fwdlist::_Node<_Ptr>;
using _Base_ptr
= typename __fwdlist::_Node_base<__ptr_rebind<_Ptr, void>>::_Base_ptr;
template<typename _Tp>
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<value_type>*;
using reference = __maybe_const<value_type>&;
constexpr _Iterator() noexcept : _M_node() { }
_Iterator(const _Iterator&) = default;
_Iterator& operator=(const _Iterator&) = default;
#ifdef __glibcxx_concepts
constexpr
_Iterator(const _Iterator<false, _Ptr>& __i) requires _Const
#else
template<bool _OtherConst,
typename = __enable_if_t<_Const && !_OtherConst>>
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<typename _Tp, typename _Allocator>
friend class _GLIBCXX_STD_C::forward_list;
template<typename _Tp, typename _Allocator>
friend struct _GLIBCXX_STD_C::_Fwd_list_base;
constexpr _Iterator<false, _Ptr>
_M_const_cast() const noexcept
{ return _Iterator<false, _Ptr>(_M_node); }
friend _Iterator<!_Const, _Ptr>;
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<typename _Tp, typename _Ptr>
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<typename _Tp>
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<typename _Tp, typename _Ptr>
struct _Node_traits
: _Node_traits<_Tp, _Tp*>
{ };
#else
// Primary template used when the allocator uses fancy pointers.
template<typename _Tp, typename _Ptr>
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<false, _ValPtr>;
using _Const_iterator = __fwdlist::_Iterator<true, _ValPtr>;
};
#endif // USE_ALLOC_PTR_FOR_FWD_LIST
} // namespace __fwdlist
/**
* @brief Base class for %forward_list.
*/
template<typename _Tp, typename _Alloc>
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<typename... _Args>
_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<typename... _Args>
_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 <a href="tables.html#65">container</a>, a
* <a href="tables.html#67">sequence</a>, including the
* <a href="tables.html#68">optional sequence requirements</a> 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<typename _Tp, typename _Alloc = allocator<_Tp>>
class forward_list : private _Fwd_list_base<_Tp, _Alloc>
{
static_assert(is_same<typename remove_cv<_Tp>::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<typename _Alloc::value_type, _Tp>::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<typename _InputIterator,
typename = std::_RequireInputIter<_InputIterator>>
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<typename _InputIterator,
typename = std::_RequireInputIter<_InputIterator>>
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>(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<typename... _Args>
#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>(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<typename... _Args>
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<typename _InputIterator,
typename = std::_RequireInputIter<_InputIterator>>
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<typename _Pred>
__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<typename _BinPred>
__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<typename _Comp>
void
merge(forward_list&& __list, _Comp __comp);
template<typename _Comp>
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<typename _Comp>
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<typename _InputIterator>
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<T, fancy-pointer>, 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<typename _Alloc_traits::pointer, _Tp*>::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<typename _Alloc_traits::pointer, _Tp*>::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<typename _Alloc_traits::pointer, _Tp*>::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<typename _Alloc_traits::pointer, _Tp*>::value)
#endif
{
clear();
insert_after(cbefore_begin(), __n, __val);
}
}
#pragma GCC diagnostic pop
#endif // ! _GLIBCXX_INLINE_VERSION
};
#if __cpp_deduction_guides >= 201606
template<typename _InputIterator, typename _ValT
= typename iterator_traits<_InputIterator>::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<ranges::input_range _Rg,
typename _Allocator = allocator<ranges::range_value_t<_Rg>>>
forward_list(from_range_t, _Rg&&, _Allocator = _Allocator())
-> forward_list<ranges::range_value_t<_Rg>, _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<typename _Tp, typename _Alloc>
[[__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<typename _Tp, typename _Alloc>
[[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<typename _Tp, typename _Alloc>
[[__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<typename _Tp, typename _Alloc>
[[__nodiscard__]]
inline bool
operator!=(const forward_list<_Tp, _Alloc>& __lx,
const forward_list<_Tp, _Alloc>& __ly)
{ return !(__lx == __ly); }
/// Based on operator<
template<typename _Tp, typename _Alloc>
[[__nodiscard__]]
inline bool
operator>(const forward_list<_Tp, _Alloc>& __lx,
const forward_list<_Tp, _Alloc>& __ly)
{ return (__ly < __lx); }
/// Based on operator<
template<typename _Tp, typename _Alloc>
[[__nodiscard__]]
inline bool
operator>=(const forward_list<_Tp, _Alloc>& __lx,
const forward_list<_Tp, _Alloc>& __ly)
{ return !(__lx < __ly); }
/// Based on operator<
template<typename _Tp, typename _Alloc>
[[__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<typename _Tp, typename _Alloc>
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