LCOM1920-T02G10

// -*- C++ -*-

//===---------------------------- list ------------------------------------===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is dual licensed under the MIT and the University of Illinois Open

// Source Licenses. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_LIST

#define _LIBCPP_LIST

/*

    list synopsis

namespace std

{

template <class T, class Alloc = allocator<T> >

class list

{

public:

    // types:

    typedef T value_type;

    typedef Alloc allocator_type;

    typedef typename allocator_type::reference reference;

    typedef typename allocator_type::const_reference const_reference;

    typedef typename allocator_type::pointer pointer;

    typedef typename allocator_type::const_pointer const_pointer;

    typedef implementation-defined iterator;

    typedef implementation-defined const_iterator;

    typedef implementation-defined size_type;

    typedef implementation-defined difference_type;

    typedef reverse_iterator<iterator> reverse_iterator;

    typedef reverse_iterator<const_iterator> const_reverse_iterator;

    list()

        noexcept(is_nothrow_default_constructible<allocator_type>::value);

    explicit list(const allocator_type& a);

    explicit list(size_type n);

    explicit list(size_type n, const allocator_type& a); // C++14

    list(size_type n, const value_type& value);

    list(size_type n, const value_type& value, const allocator_type& a);

    template <class Iter>

        list(Iter first, Iter last);

    template <class Iter>

        list(Iter first, Iter last, const allocator_type& a);

    list(const list& x);

    list(const list&, const allocator_type& a);

    list(list&& x)

        noexcept(is_nothrow_move_constructible<allocator_type>::value);

    list(list&&, const allocator_type& a);

    list(initializer_list<value_type>);

    list(initializer_list<value_type>, const allocator_type& a);

    ~list();

    list& operator=(const list& x);

    list& operator=(list&& x)

        noexcept(

             allocator_type::propagate_on_container_move_assignment::value &&

             is_nothrow_move_assignable<allocator_type>::value);

    list& operator=(initializer_list<value_type>);

    template <class Iter>

        void assign(Iter first, Iter last);

    void assign(size_type n, const value_type& t);

    void assign(initializer_list<value_type>);

    allocator_type get_allocator() const noexcept;

    iterator begin() noexcept;

    const_iterator begin() const noexcept;

    iterator end() noexcept;

    const_iterator end() const noexcept;

    reverse_iterator rbegin() noexcept;

    const_reverse_iterator rbegin() const noexcept;

    reverse_iterator rend() noexcept;

    const_reverse_iterator rend() const noexcept;

    const_iterator cbegin() const noexcept;

    const_iterator cend() const noexcept;

    const_reverse_iterator crbegin() const noexcept;

    const_reverse_iterator crend() const noexcept;

    reference front();

    const_reference front() const;

    reference back();

    const_reference back() const;

    bool empty() const noexcept;

    size_type size() const noexcept;

    size_type max_size() const noexcept;

    template <class... Args>

        void emplace_front(Args&&... args);

    void pop_front();

    template <class... Args>

        void emplace_back(Args&&... args);

    void pop_back();

    void push_front(const value_type& x);

    void push_front(value_type&& x);

    void push_back(const value_type& x);

    void push_back(value_type&& x);

    template <class... Args>

        iterator emplace(const_iterator position, Args&&... args);

    iterator insert(const_iterator position, const value_type& x);

    iterator insert(const_iterator position, value_type&& x);

    iterator insert(const_iterator position, size_type n, const value_type& x);

    template <class Iter>

        iterator insert(const_iterator position, Iter first, Iter last);

    iterator insert(const_iterator position, initializer_list<value_type> il);

    iterator erase(const_iterator position);

    iterator erase(const_iterator position, const_iterator last);

    void resize(size_type sz);

    void resize(size_type sz, const value_type& c);

    void swap(list&)

        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17

    void clear() noexcept;

    void splice(const_iterator position, list& x);

    void splice(const_iterator position, list&& x);

    void splice(const_iterator position, list& x, const_iterator i);

    void splice(const_iterator position, list&& x, const_iterator i);

    void splice(const_iterator position, list& x, const_iterator first,

                                                  const_iterator last);

    void splice(const_iterator position, list&& x, const_iterator first,

                                                  const_iterator last);

    void remove(const value_type& value);

    template <class Pred> void remove_if(Pred pred);

    void unique();

    template <class BinaryPredicate>

        void unique(BinaryPredicate binary_pred);

    void merge(list& x);

    void merge(list&& x);

    template <class Compare>

        void merge(list& x, Compare comp);

    template <class Compare>

        void merge(list&& x, Compare comp);

    void sort();

    template <class Compare>

        void sort(Compare comp);

    void reverse() noexcept;

};

template <class T, class Alloc>

    bool operator==(const list<T,Alloc>& x, const list<T,Alloc>& y);

template <class T, class Alloc>

    bool operator< (const list<T,Alloc>& x, const list<T,Alloc>& y);

template <class T, class Alloc>

    bool operator!=(const list<T,Alloc>& x, const list<T,Alloc>& y);

template <class T, class Alloc>

    bool operator> (const list<T,Alloc>& x, const list<T,Alloc>& y);

template <class T, class Alloc>

    bool operator>=(const list<T,Alloc>& x, const list<T,Alloc>& y);

template <class T, class Alloc>

    bool operator<=(const list<T,Alloc>& x, const list<T,Alloc>& y);

template <class T, class Alloc>

    void swap(list<T,Alloc>& x, list<T,Alloc>& y)

         noexcept(noexcept(x.swap(y)));

}  // std

*/

#include <__config>

#include <memory>

#include <limits>

#include <initializer_list>

#include <iterator>

#include <algorithm>

#include <__undef_min_max>

#include <__debug>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

#pragma GCC system_header

#endif

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _Tp, class _VoidPtr> struct __list_node;

template <class _Tp, class _VoidPtr>

struct __list_node_base

{

    typedef typename pointer_traits<_VoidPtr>::template

#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES

        rebind<__list_node<_Tp, _VoidPtr> > pointer;

#else

        rebind<__list_node<_Tp, _VoidPtr> >::other pointer;

#endif

    typedef typename pointer_traits<_VoidPtr>::template

#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES

        rebind<__list_node_base> __base_pointer;

#else

        rebind<__list_node_base>::other __base_pointer;

#endif

    pointer __prev_;

    pointer __next_;

    _LIBCPP_INLINE_VISIBILITY

    __list_node_base() : __prev_(__self()), __next_(__self()) {}

    _LIBCPP_INLINE_VISIBILITY

    pointer __self()

    {

        return static_cast<pointer>(pointer_traits<__base_pointer>::pointer_to(*this));

    }

};

template <class _Tp, class _VoidPtr>

struct __list_node

    : public __list_node_base<_Tp, _VoidPtr>

{

    _Tp __value_;

};

template <class _Tp, class _Alloc = allocator<_Tp> > class _LIBCPP_TYPE_VIS_ONLY list;

template <class _Tp, class _Alloc> class __list_imp;

template <class _Tp, class _VoidPtr> class _LIBCPP_TYPE_VIS_ONLY __list_const_iterator;

template <class _Tp, class _VoidPtr>

class _LIBCPP_TYPE_VIS_ONLY __list_iterator

{

    typedef typename pointer_traits<_VoidPtr>::template

#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES

        rebind<__list_node<_Tp, _VoidPtr> > __node_pointer;

#else

        rebind<__list_node<_Tp, _VoidPtr> >::other __node_pointer;

#endif

    __node_pointer __ptr_;

#if _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_INLINE_VISIBILITY

    explicit __list_iterator(__node_pointer __p, const void* __c) _NOEXCEPT

        : __ptr_(__p)

    {

        __get_db()->__insert_ic(this, __c);

    }

#else

    _LIBCPP_INLINE_VISIBILITY

    explicit __list_iterator(__node_pointer __p) _NOEXCEPT : __ptr_(__p) {}

#endif

    template<class, class> friend class list;

    template<class, class> friend class __list_imp;

    template<class, class> friend class __list_const_iterator;

public:

    typedef bidirectional_iterator_tag       iterator_category;

    typedef _Tp                              value_type;

    typedef value_type&                      reference;

    typedef typename pointer_traits<_VoidPtr>::template

#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES

            rebind<value_type>

#else

            rebind<value_type>::other

#endif

                                             pointer;

    typedef typename pointer_traits<pointer>::difference_type difference_type;

    _LIBCPP_INLINE_VISIBILITY

    __list_iterator() _NOEXCEPT : __ptr_(nullptr)

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        __get_db()->__insert_i(this);

#endif

    }

#if _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_INLINE_VISIBILITY

    __list_iterator(const __list_iterator& __p)

        : __ptr_(__p.__ptr_)

    {

        __get_db()->__iterator_copy(this, &__p);

    }

    _LIBCPP_INLINE_VISIBILITY

    ~__list_iterator()

    {

        __get_db()->__erase_i(this);

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_iterator& operator=(const __list_iterator& __p)

    {

        if (this != &__p)

        {

            __get_db()->__iterator_copy(this, &__p);

            __ptr_ = __p.__ptr_;

        }

        return *this;

    }

#endif  // _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_INLINE_VISIBILITY

    reference operator*() const

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),

                       "Attempted to dereference a non-dereferenceable list::iterator");

#endif

        return __ptr_->__value_;

    }

    _LIBCPP_INLINE_VISIBILITY

    pointer operator->() const

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),

                       "Attempted to dereference a non-dereferenceable list::iterator");

#endif

        return pointer_traits<pointer>::pointer_to(__ptr_->__value_);

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_iterator& operator++()

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),

                       "Attempted to increment non-incrementable list::iterator");

#endif

        __ptr_ = __ptr_->__next_;

        return *this;

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_iterator operator++(int) {__list_iterator __t(*this); ++(*this); return __t;}

    _LIBCPP_INLINE_VISIBILITY

    __list_iterator& operator--()

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),

                       "Attempted to decrement non-decrementable list::iterator");

#endif

        __ptr_ = __ptr_->__prev_;

        return *this;

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_iterator operator--(int) {__list_iterator __t(*this); --(*this); return __t;}

    friend _LIBCPP_INLINE_VISIBILITY

    bool operator==(const __list_iterator& __x, const __list_iterator& __y)

    {

        return __x.__ptr_ == __y.__ptr_;

    }

    friend _LIBCPP_INLINE_VISIBILITY

     bool operator!=(const __list_iterator& __x, const __list_iterator& __y)

        {return !(__x == __y);}

};

template <class _Tp, class _VoidPtr>

class _LIBCPP_TYPE_VIS_ONLY __list_const_iterator

{

    typedef typename pointer_traits<_VoidPtr>::template

#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES

        rebind<__list_node<_Tp, _VoidPtr> > __node_pointer;

#else

        rebind<__list_node<_Tp, _VoidPtr> >::other __node_pointer;

#endif

    __node_pointer __ptr_;

#if _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_INLINE_VISIBILITY

    explicit __list_const_iterator(__node_pointer __p, const void* __c) _NOEXCEPT

        : __ptr_(__p)

    {

        __get_db()->__insert_ic(this, __c);

    }

#else

    _LIBCPP_INLINE_VISIBILITY

    explicit __list_const_iterator(__node_pointer __p) _NOEXCEPT : __ptr_(__p) {}

#endif

    template<class, class> friend class list;

    template<class, class> friend class __list_imp;

public:

    typedef bidirectional_iterator_tag       iterator_category;

    typedef _Tp                              value_type;

    typedef const value_type&                reference;

    typedef typename pointer_traits<_VoidPtr>::template

#ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES

            rebind<const value_type>

#else

            rebind<const value_type>::other

#endif

                                             pointer;

    typedef typename pointer_traits<pointer>::difference_type difference_type;

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator() _NOEXCEPT : __ptr_(nullptr)

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        __get_db()->__insert_i(this);

#endif

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator(const __list_iterator<_Tp, _VoidPtr>& __p) _NOEXCEPT

        : __ptr_(__p.__ptr_)

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        __get_db()->__iterator_copy(this, &__p);

#endif

    }

#if _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator(const __list_const_iterator& __p)

        : __ptr_(__p.__ptr_)

    {

        __get_db()->__iterator_copy(this, &__p);

    }

    _LIBCPP_INLINE_VISIBILITY

    ~__list_const_iterator()

    {

        __get_db()->__erase_i(this);

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator& operator=(const __list_const_iterator& __p)

    {

        if (this != &__p)

        {

            __get_db()->__iterator_copy(this, &__p);

            __ptr_ = __p.__ptr_;

        }

        return *this;

    }

#endif  // _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_INLINE_VISIBILITY

    reference operator*() const

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),

                       "Attempted to dereference a non-dereferenceable list::const_iterator");

#endif

        return __ptr_->__value_;

    }

    _LIBCPP_INLINE_VISIBILITY

    pointer operator->() const

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),

                       "Attempted to dereference a non-dereferenceable list::iterator");

#endif

        return pointer_traits<pointer>::pointer_to(__ptr_->__value_);

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator& operator++()

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),

                       "Attempted to increment non-incrementable list::const_iterator");

#endif

        __ptr_ = __ptr_->__next_;

        return *this;

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator operator++(int) {__list_const_iterator __t(*this); ++(*this); return __t;}

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator& operator--()

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),

                       "Attempted to decrement non-decrementable list::const_iterator");

#endif

        __ptr_ = __ptr_->__prev_;

        return *this;

    }

    _LIBCPP_INLINE_VISIBILITY

    __list_const_iterator operator--(int) {__list_const_iterator __t(*this); --(*this); return __t;}

    friend _LIBCPP_INLINE_VISIBILITY

    bool operator==(const __list_const_iterator& __x, const __list_const_iterator& __y)

    {

        return __x.__ptr_ == __y.__ptr_;

    }

    friend _LIBCPP_INLINE_VISIBILITY

    bool operator!=(const __list_const_iterator& __x, const __list_const_iterator& __y)

        {return !(__x == __y);}

};

template <class _Tp, class _Alloc>

class __list_imp

{

    __list_imp(const __list_imp&);

    __list_imp& operator=(const __list_imp&);

protected:

    typedef _Tp                                                     value_type;

    typedef _Alloc                                                  allocator_type;

    typedef allocator_traits<allocator_type>                        __alloc_traits;

    typedef typename __alloc_traits::size_type                      size_type;

    typedef typename __alloc_traits::void_pointer                   __void_pointer;

    typedef __list_iterator<value_type, __void_pointer>             iterator;

    typedef __list_const_iterator<value_type, __void_pointer>       const_iterator;

    typedef __list_node_base<value_type, __void_pointer>            __node_base;

    typedef __list_node<value_type, __void_pointer>                 __node;

    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;

    typedef allocator_traits<__node_allocator>                       __node_alloc_traits;

    typedef typename __node_alloc_traits::pointer                    __node_pointer;

    typedef typename __node_alloc_traits::pointer                    __node_const_pointer;

    typedef typename __alloc_traits::pointer                         pointer;

    typedef typename __alloc_traits::const_pointer                   const_pointer;

    typedef typename __alloc_traits::difference_type                 difference_type;

    typedef typename __rebind_alloc_helper<__alloc_traits, __node_base>::type __node_base_allocator;

    typedef typename allocator_traits<__node_base_allocator>::pointer __node_base_pointer;

    __node_base __end_;

    __compressed_pair<size_type, __node_allocator> __size_alloc_;

    _LIBCPP_INLINE_VISIBILITY

          size_type& __sz() _NOEXCEPT {return __size_alloc_.first();}

    _LIBCPP_INLINE_VISIBILITY

    const size_type& __sz() const _NOEXCEPT

        {return __size_alloc_.first();}

    _LIBCPP_INLINE_VISIBILITY

          __node_allocator& __node_alloc() _NOEXCEPT

          {return __size_alloc_.second();}

    _LIBCPP_INLINE_VISIBILITY

    const __node_allocator& __node_alloc() const _NOEXCEPT

        {return __size_alloc_.second();}

    static void __unlink_nodes(__node_pointer __f, __node_pointer __l) _NOEXCEPT;

    __list_imp()

        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value);

    __list_imp(const allocator_type& __a);

    ~__list_imp();

    void clear() _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY

    bool empty() const _NOEXCEPT {return __sz() == 0;}

    _LIBCPP_INLINE_VISIBILITY

    iterator begin() _NOEXCEPT

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        return iterator(__end_.__next_, this);

#else

        return iterator(__end_.__next_);

#endif

    }

    _LIBCPP_INLINE_VISIBILITY

    const_iterator begin() const  _NOEXCEPT

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        return const_iterator(__end_.__next_, this);

#else

        return const_iterator(__end_.__next_);

#endif

    }

    _LIBCPP_INLINE_VISIBILITY

    iterator end() _NOEXCEPT

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        return iterator(static_cast<__node_pointer>(

                pointer_traits<__node_base_pointer>::pointer_to(__end_)), this);

#else

        return iterator(static_cast<__node_pointer>(

                      pointer_traits<__node_base_pointer>::pointer_to(__end_)));

#endif

    }

    _LIBCPP_INLINE_VISIBILITY

    const_iterator end() const _NOEXCEPT

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        return const_iterator(static_cast<__node_const_pointer>(

        pointer_traits<__node_base_pointer>::pointer_to(const_cast<__node_base&>(__end_))), this);

#else

        return const_iterator(static_cast<__node_const_pointer>(

        pointer_traits<__node_base_pointer>::pointer_to(const_cast<__node_base&>(__end_))));

#endif

    }

    void swap(__list_imp& __c)

#if _LIBCPP_STD_VER >= 14

        _NOEXCEPT;

#else

        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || 

                    __is_nothrow_swappable<allocator_type>::value);

#endif

    _LIBCPP_INLINE_VISIBILITY

    void __copy_assign_alloc(const __list_imp& __c)

        {__copy_assign_alloc(__c, integral_constant<bool,

                      __node_alloc_traits::propagate_on_container_copy_assignment::value>());}

    _LIBCPP_INLINE_VISIBILITY

    void __move_assign_alloc(__list_imp& __c)

        _NOEXCEPT_(

            !__node_alloc_traits::propagate_on_container_move_assignment::value ||

            is_nothrow_move_assignable<__node_allocator>::value)

        {__move_assign_alloc(__c, integral_constant<bool,

                      __node_alloc_traits::propagate_on_container_move_assignment::value>());}

private:

    _LIBCPP_INLINE_VISIBILITY

    void __copy_assign_alloc(const __list_imp& __c, true_type)

        {

            if (__node_alloc() != __c.__node_alloc())

                clear();

            __node_alloc() = __c.__node_alloc();

        }

    _LIBCPP_INLINE_VISIBILITY

    void __copy_assign_alloc(const __list_imp& __c, false_type)

        {}

    _LIBCPP_INLINE_VISIBILITY

    void __move_assign_alloc(__list_imp& __c, true_type)

        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)

        {

            __node_alloc() = _VSTD::move(__c.__node_alloc());

        }

    _LIBCPP_INLINE_VISIBILITY

    void __move_assign_alloc(__list_imp& __c, false_type)

        _NOEXCEPT

        {}

};

// Unlink nodes [__f, __l]

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

void

__list_imp<_Tp, _Alloc>::__unlink_nodes(__node_pointer __f, __node_pointer __l)

    _NOEXCEPT

{

    __f->__prev_->__next_ = __l->__next_;

    __l->__next_->__prev_ = __f->__prev_;

}

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

__list_imp<_Tp, _Alloc>::__list_imp()

        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)

    : __size_alloc_(0)

{

}

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

__list_imp<_Tp, _Alloc>::__list_imp(const allocator_type& __a)

    : __size_alloc_(0, __node_allocator(__a))

{

}

template <class _Tp, class _Alloc>

__list_imp<_Tp, _Alloc>::~__list_imp()

{

    clear();

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__erase_c(this);

#endif

}

template <class _Tp, class _Alloc>

void

__list_imp<_Tp, _Alloc>::clear() _NOEXCEPT

{

    if (!empty())

    {

        __node_allocator& __na = __node_alloc();

        __node_pointer __f = __end_.__next_;

        __node_pointer __l = static_cast<__node_pointer>(

                       pointer_traits<__node_base_pointer>::pointer_to(__end_));

        __unlink_nodes(__f, __l->__prev_);

        __sz() = 0;

        while (__f != __l)

        {

            __node_pointer __n = __f;

            __f = __f->__next_;

            __node_alloc_traits::destroy(__na, _VSTD::addressof(__n->__value_));

            __node_alloc_traits::deallocate(__na, __n, 1);

        }

#if _LIBCPP_DEBUG_LEVEL >= 2

        __c_node* __c = __get_db()->__find_c_and_lock(this);

        for (__i_node** __p = __c->end_; __p != __c->beg_; )

        {

            --__p;

            const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);

            if (__i->__ptr_ != __l)

            {

                (*__p)->__c_ = nullptr;

                if (--__c->end_ != __p)

                    memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));

            }

        }

        __get_db()->unlock();

#endif

    }

}

template <class _Tp, class _Alloc>

void

__list_imp<_Tp, _Alloc>::swap(__list_imp& __c)

#if _LIBCPP_STD_VER >= 14

        _NOEXCEPT

#else

        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || 

                    __is_nothrow_swappable<allocator_type>::value)

#endif

{

    _LIBCPP_ASSERT(__alloc_traits::propagate_on_container_swap::value ||

                   this->__node_alloc() == __c.__node_alloc(),

                   "list::swap: Either propagate_on_container_swap must be true"

                   " or the allocators must compare equal");

    using _VSTD::swap;

    __swap_allocator(__node_alloc(), __c.__node_alloc());

    swap(__sz(), __c.__sz());

    swap(__end_, __c.__end_);

    if (__sz() == 0)

        __end_.__next_ = __end_.__prev_ = __end_.__self();

    else

        __end_.__prev_->__next_ = __end_.__next_->__prev_ = __end_.__self();

    if (__c.__sz() == 0)

        __c.__end_.__next_ = __c.__end_.__prev_ = __c.__end_.__self();

    else

        __c.__end_.__prev_->__next_ = __c.__end_.__next_->__prev_ = __c.__end_.__self();

#if _LIBCPP_DEBUG_LEVEL >= 2

    __libcpp_db* __db = __get_db();

    __c_node* __cn1 = __db->__find_c_and_lock(this);

    __c_node* __cn2 = __db->__find_c(&__c);

    std::swap(__cn1->beg_, __cn2->beg_);

    std::swap(__cn1->end_, __cn2->end_);

    std::swap(__cn1->cap_, __cn2->cap_);

    for (__i_node** __p = __cn1->end_; __p != __cn1->beg_;)

    {

        --__p;

        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);

        if (__i->__ptr_ == static_cast<__node_pointer>(

                       pointer_traits<__node_base_pointer>::pointer_to(__c.__end_)))

        {

            __cn2->__add(*__p);

            if (--__cn1->end_ != __p)

                memmove(__p, __p+1, (__cn1->end_ - __p)*sizeof(__i_node*));

        }

        else

            (*__p)->__c_ = __cn1;

    }

    for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)

    {

        --__p;

        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);

        if (__i->__ptr_ == static_cast<__node_pointer>(

                       pointer_traits<__node_base_pointer>::pointer_to(__end_)))

        {

            __cn1->__add(*__p);

            if (--__cn2->end_ != __p)

                memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));

        }

        else

            (*__p)->__c_ = __cn2;

    }

    __db->unlock();

#endif

}

template <class _Tp, class _Alloc /*= allocator<_Tp>*/>

class _LIBCPP_TYPE_VIS_ONLY list

    : private __list_imp<_Tp, _Alloc>

{

    typedef __list_imp<_Tp, _Alloc> base;

    typedef typename base::__node              __node;

    typedef typename base::__node_allocator    __node_allocator;

    typedef typename base::__node_pointer      __node_pointer;

    typedef typename base::__node_alloc_traits __node_alloc_traits;

    typedef typename base::__node_base         __node_base;

    typedef typename base::__node_base_pointer __node_base_pointer;

public:

    typedef _Tp                                      value_type;

    typedef _Alloc                                   allocator_type;

    static_assert((is_same<value_type, typename allocator_type::value_type>::value),

                  "Invalid allocator::value_type");

    typedef value_type&                              reference;

    typedef const value_type&                        const_reference;

    typedef typename base::pointer                   pointer;

    typedef typename base::const_pointer             const_pointer;

    typedef typename base::size_type                 size_type;

    typedef typename base::difference_type           difference_type;

    typedef typename base::iterator                  iterator;

    typedef typename base::const_iterator            const_iterator;

    typedef _VSTD::reverse_iterator<iterator>         reverse_iterator;

    typedef _VSTD::reverse_iterator<const_iterator>   const_reverse_iterator;

    _LIBCPP_INLINE_VISIBILITY

    list()

        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        __get_db()->__insert_c(this);

#endif

    }

    _LIBCPP_INLINE_VISIBILITY

    explicit list(const allocator_type& __a) : base(__a)

    {

#if _LIBCPP_DEBUG_LEVEL >= 2

        __get_db()->__insert_c(this);

#endif

    }

    explicit list(size_type __n);

#if _LIBCPP_STD_VER > 11

    explicit list(size_type __n, const allocator_type& __a);

#endif

    list(size_type __n, const value_type& __x);

    list(size_type __n, const value_type& __x, const allocator_type& __a);

    template <class _InpIter>

        list(_InpIter __f, _InpIter __l,

             typename enable_if<__is_input_iterator<_InpIter>::value>::type* = 0);

    template <class _InpIter>

        list(_InpIter __f, _InpIter __l, const allocator_type& __a,

             typename enable_if<__is_input_iterator<_InpIter>::value>::type* = 0);

    list(const list& __c);

    list(const list& __c, const allocator_type& __a);

    list& operator=(const list& __c);

#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

    list(initializer_list<value_type> __il);

    list(initializer_list<value_type> __il, const allocator_type& __a);

#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    list(list&& __c)

        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);

    list(list&& __c, const allocator_type& __a);

    list& operator=(list&& __c)

        _NOEXCEPT_(

            __node_alloc_traits::propagate_on_container_move_assignment::value &&

            is_nothrow_move_assignable<__node_allocator>::value);

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

    _LIBCPP_INLINE_VISIBILITY

    list& operator=(initializer_list<value_type> __il)

        {assign(__il.begin(), __il.end()); return *this;}

#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

    template <class _InpIter>

        void assign(_InpIter __f, _InpIter __l,

             typename enable_if<__is_input_iterator<_InpIter>::value>::type* = 0);

    void assign(size_type __n, const value_type& __x);

#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

    _LIBCPP_INLINE_VISIBILITY

    void assign(initializer_list<value_type> __il)

        {assign(__il.begin(), __il.end());}

#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

    allocator_type get_allocator() const _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY

    size_type size() const _NOEXCEPT     {return base::__sz();}

    _LIBCPP_INLINE_VISIBILITY

    bool empty() const _NOEXCEPT         {return base::empty();}

    _LIBCPP_INLINE_VISIBILITY

    size_type max_size() const _NOEXCEPT

        {return numeric_limits<difference_type>::max();}

    _LIBCPP_INLINE_VISIBILITY

          iterator begin() _NOEXCEPT        {return base::begin();}

    _LIBCPP_INLINE_VISIBILITY

    const_iterator begin()  const _NOEXCEPT {return base::begin();}

    _LIBCPP_INLINE_VISIBILITY

          iterator end() _NOEXCEPT          {return base::end();}

    _LIBCPP_INLINE_VISIBILITY

    const_iterator end()    const _NOEXCEPT {return base::end();}

    _LIBCPP_INLINE_VISIBILITY

    const_iterator cbegin() const _NOEXCEPT {return base::begin();}

    _LIBCPP_INLINE_VISIBILITY

    const_iterator cend()   const _NOEXCEPT {return base::end();}

    _LIBCPP_INLINE_VISIBILITY

          reverse_iterator rbegin() _NOEXCEPT

            {return       reverse_iterator(end());}

    _LIBCPP_INLINE_VISIBILITY

    const_reverse_iterator rbegin()  const _NOEXCEPT

        {return const_reverse_iterator(end());}

    _LIBCPP_INLINE_VISIBILITY

          reverse_iterator rend() _NOEXCEPT

            {return       reverse_iterator(begin());}

    _LIBCPP_INLINE_VISIBILITY

    const_reverse_iterator rend()    const _NOEXCEPT

        {return const_reverse_iterator(begin());}

    _LIBCPP_INLINE_VISIBILITY

    const_reverse_iterator crbegin() const _NOEXCEPT

        {return const_reverse_iterator(end());}

    _LIBCPP_INLINE_VISIBILITY

    const_reverse_iterator crend()   const _NOEXCEPT

        {return const_reverse_iterator(begin());}

    _LIBCPP_INLINE_VISIBILITY

    reference front()

    {

        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");

        return base::__end_.__next_->__value_;

    }

    _LIBCPP_INLINE_VISIBILITY

    const_reference front() const

    {

        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");

        return base::__end_.__next_->__value_;

    }

    _LIBCPP_INLINE_VISIBILITY

    reference back()

    {

        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");

        return base::__end_.__prev_->__value_;

    }

    _LIBCPP_INLINE_VISIBILITY

    const_reference back() const

    {

        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");

        return base::__end_.__prev_->__value_;

    }

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    void push_front(value_type&& __x);

    void push_back(value_type&& __x);

#ifndef _LIBCPP_HAS_NO_VARIADICS

    template <class... _Args>

       void emplace_front(_Args&&... __args);

    template <class... _Args>

        void emplace_back(_Args&&... __args);

    template <class... _Args>

        iterator emplace(const_iterator __p, _Args&&... __args);

#endif  // _LIBCPP_HAS_NO_VARIADICS

    iterator insert(const_iterator __p, value_type&& __x);

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

    void push_front(const value_type& __x);

    void push_back(const value_type& __x);

    iterator insert(const_iterator __p, const value_type& __x);

    iterator insert(const_iterator __p, size_type __n, const value_type& __x);

    template <class _InpIter>

        iterator insert(const_iterator __p, _InpIter __f, _InpIter __l,

             typename enable_if<__is_input_iterator<_InpIter>::value>::type* = 0);

#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

    _LIBCPP_INLINE_VISIBILITY

    iterator insert(const_iterator __p, initializer_list<value_type> __il)

        {return insert(__p, __il.begin(), __il.end());}

#endif   // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

    _LIBCPP_INLINE_VISIBILITY

    void swap(list& __c)

#if _LIBCPP_STD_VER >= 14

        _NOEXCEPT

#else

        _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_swap::value ||

                   __is_nothrow_swappable<__node_allocator>::value)

#endif

        {base::swap(__c);}

    _LIBCPP_INLINE_VISIBILITY

    void clear() _NOEXCEPT {base::clear();}

    void pop_front();

    void pop_back();

    iterator erase(const_iterator __p);

    iterator erase(const_iterator __f, const_iterator __l);

    void resize(size_type __n);

    void resize(size_type __n, const value_type& __x);

    void splice(const_iterator __p, list& __c);

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY

    void splice(const_iterator __p, list&& __c) {splice(__p, __c);}

#endif

    void splice(const_iterator __p, list& __c, const_iterator __i);

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY

    void splice(const_iterator __p, list&& __c, const_iterator __i)

        {splice(__p, __c, __i);}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

    void splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l);

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY

    void splice(const_iterator __p, list&& __c, const_iterator __f, const_iterator __l)

        {splice(__p, __c, __f, __l);}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

    void remove(const value_type& __x);

    template <class _Pred> void remove_if(_Pred __pred);

    void unique();

    template <class _BinaryPred>

        void unique(_BinaryPred __binary_pred);

    void merge(list& __c);

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY

    void merge(list&& __c) {merge(__c);}

#endif

    template <class _Comp>

        void merge(list& __c, _Comp __comp);

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    template <class _Comp>

    _LIBCPP_INLINE_VISIBILITY

        void merge(list&& __c, _Comp __comp) {merge(__c, __comp);}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

    void sort();

    template <class _Comp>

        void sort(_Comp __comp);

    void reverse() _NOEXCEPT;

    bool __invariants() const;

#if _LIBCPP_DEBUG_LEVEL >= 2

    bool __dereferenceable(const const_iterator* __i) const;

    bool __decrementable(const const_iterator* __i) const;

    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;

    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;

#endif  // _LIBCPP_DEBUG_LEVEL >= 2

private:

    static void __link_nodes  (__node_pointer __p, __node_pointer __f, __node_pointer __l);

    void __link_nodes_at_front(__node_pointer __f, __node_pointer __l);

    void __link_nodes_at_back (__node_pointer __f, __node_pointer __l);

    iterator __iterator(size_type __n);

    template <class _Comp>

        static iterator __sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp);

    void __move_assign(list& __c, true_type)

        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value);

    void __move_assign(list& __c, false_type);

};

// Link in nodes [__f, __l] just prior to __p

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

void

list<_Tp, _Alloc>::__link_nodes(__node_pointer __p, __node_pointer __f, __node_pointer __l)

{

    __p->__prev_->__next_ = __f;

    __f->__prev_ = __p->__prev_;

    __p->__prev_ = __l;

    __l->__next_ = __p;

}

// Link in nodes [__f, __l] at the front of the list

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

void

list<_Tp, _Alloc>::__link_nodes_at_front(__node_pointer __f, __node_pointer __l)

{

    __f->__prev_ = base::__end_.__self();

    __l->__next_ = base::__end_.__next_;

    __l->__next_->__prev_ = __l;

    base::__end_.__next_ = __f;

}

// Link in nodes [__f, __l] at the front of the list

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

void

list<_Tp, _Alloc>::__link_nodes_at_back(__node_pointer __f, __node_pointer __l)

{

    __l->__next_ = base::__end_.__self();

    __f->__prev_ = base::__end_.__prev_;

    __f->__prev_->__next_ = __f;

    base::__end_.__prev_ = __l;

}

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

typename list<_Tp, _Alloc>::iterator

list<_Tp, _Alloc>::__iterator(size_type __n)

{

    return __n <= base::__sz() / 2 ? _VSTD::next(begin(), __n)

                                   : _VSTD::prev(end(), base::__sz() - __n);

}

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(size_type __n)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (; __n > 0; --__n)

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

        emplace_back();

#else

        push_back(value_type());

#endif

}

#if _LIBCPP_STD_VER > 11

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(size_type __n, const allocator_type& __a) : base(__a)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (; __n > 0; --__n)

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

        emplace_back();

#else

        push_back(value_type());

#endif

}

#endif

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(size_type __n, const value_type& __x)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (; __n > 0; --__n)

        push_back(__x);

}

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(size_type __n, const value_type& __x, const allocator_type& __a)

    : base(__a)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (; __n > 0; --__n)

        push_back(__x);

}

template <class _Tp, class _Alloc>

template <class _InpIter>

list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l,

                        typename enable_if<__is_input_iterator<_InpIter>::value>::type*)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (; __f != __l; ++__f)

        push_back(*__f);

}

template <class _Tp, class _Alloc>

template <class _InpIter>

list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l, const allocator_type& __a,

                        typename enable_if<__is_input_iterator<_InpIter>::value>::type*)

    : base(__a)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (; __f != __l; ++__f)

        push_back(*__f);

}

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(const list& __c)

    : base(allocator_type(

           __node_alloc_traits::select_on_container_copy_construction(

                __c.__node_alloc())))

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)

        push_back(*__i);

}

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(const list& __c, const allocator_type& __a)

    : base(__a)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)

        push_back(*__i);

}

#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(initializer_list<value_type> __il, const allocator_type& __a)

    : base(__a)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),

            __e = __il.end(); __i != __e; ++__i)

        push_back(*__i);

}

template <class _Tp, class _Alloc>

list<_Tp, _Alloc>::list(initializer_list<value_type> __il)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),

            __e = __il.end(); __i != __e; ++__i)

        push_back(*__i);

}

#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

list<_Tp, _Alloc>&

list<_Tp, _Alloc>::operator=(const list& __c)

{

    if (this != &__c)

    {

        base::__copy_assign_alloc(__c);

        assign(__c.begin(), __c.end());

    }

    return *this;

}

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

list<_Tp, _Alloc>::list(list&& __c)

    _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value)

    : base(allocator_type(_VSTD::move(__c.__node_alloc())))

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    splice(end(), __c);

}

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

list<_Tp, _Alloc>::list(list&& __c, const allocator_type& __a)

    : base(__a)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    __get_db()->__insert_c(this);

#endif

    if (__a == __c.get_allocator())

        splice(end(), __c);

    else

    {

        typedef move_iterator<iterator> _Ip;

        assign(_Ip(__c.begin()), _Ip(__c.end()));

    }

}

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

list<_Tp, _Alloc>&

list<_Tp, _Alloc>::operator=(list&& __c)

        _NOEXCEPT_(

            __node_alloc_traits::propagate_on_container_move_assignment::value &&

            is_nothrow_move_assignable<__node_allocator>::value)

{

    __move_assign(__c, integral_constant<bool,

          __node_alloc_traits::propagate_on_container_move_assignment::value>());

    return *this;

}

template <class _Tp, class _Alloc>

void

list<_Tp, _Alloc>::__move_assign(list& __c, false_type)

{

    if (base::__node_alloc() != __c.__node_alloc())

    {

        typedef move_iterator<iterator> _Ip;

        assign(_Ip(__c.begin()), _Ip(__c.end()));

    }

    else

        __move_assign(__c, true_type());

}

template <class _Tp, class _Alloc>

void

list<_Tp, _Alloc>::__move_assign(list& __c, true_type)

        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)

{

    clear();

    base::__move_assign_alloc(__c);

    splice(end(), __c);

}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

template <class _Tp, class _Alloc>

template <class _InpIter>

void

list<_Tp, _Alloc>::assign(_InpIter __f, _InpIter __l,

                          typename enable_if<__is_input_iterator<_InpIter>::value>::type*)

{

    iterator __i = begin();

    iterator __e = end();

    for (; __f != __l && __i != __e; ++__f, ++__i)

        *__i = *__f;

    if (__i == __e)

        insert(__e, __f, __l);

    else

        erase(__i, __e);

}

template <class _Tp, class _Alloc>

void

list<_Tp, _Alloc>::assign(size_type __n, const value_type& __x)

{

    iterator __i = begin();

    iterator __e = end();

    for (; __n > 0 && __i != __e; --__n, ++__i)

        *__i = __x;

    if (__i == __e)

        insert(__e, __n, __x);

    else

        erase(__i, __e);

}

template <class _Tp, class _Alloc>

inline _LIBCPP_INLINE_VISIBILITY

_Alloc

list<_Tp, _Alloc>::get_allocator() const _NOEXCEPT

{

    return allocator_type(base::__node_alloc());

}

template <class _Tp, class _Alloc>

typename list<_Tp, _Alloc>::iterator

list<_Tp, _Alloc>::insert(const_iterator __p, const value_type& __x)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,

        "list::insert(iterator, x) called with an iterator not"

        " referring to this list");

#endif

    __node_allocator& __na = base::__node_alloc();

    typedef __allocator_destructor<__node_allocator> _Dp;

    unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

    __hold->__prev_ = 0;

    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);

    __link_nodes(__p.__ptr_, __hold.get(), __hold.get());

    ++base::__sz();

#if _LIBCPP_DEBUG_LEVEL >= 2

    return iterator(__hold.release(), this);

#else

    return iterator(__hold.release());

#endif

}

template <class _Tp, class _Alloc>

typename list<_Tp, _Alloc>::iterator

list<_Tp, _Alloc>::insert(const_iterator __p, size_type __n, const value_type& __x)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,

        "list::insert(iterator, n, x) called with an iterator not"

        " referring to this list");

    iterator __r(__p.__ptr_, this);

#else

    iterator __r(__p.__ptr_);

#endif

    if (__n > 0)

    {

        size_type __ds = 0;

        __node_allocator& __na = base::__node_alloc();

        typedef __allocator_destructor<__node_allocator> _Dp;

        unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

        __hold->__prev_ = 0;

        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);

        ++__ds;

#if _LIBCPP_DEBUG_LEVEL >= 2

        __r = iterator(__hold.get(), this);

#else

        __r = iterator(__hold.get());

#endif

        __hold.release();

        iterator __e = __r;

#ifndef _LIBCPP_NO_EXCEPTIONS

        try

        {

#endif  // _LIBCPP_NO_EXCEPTIONS

            for (--__n; __n != 0; --__n, ++__e, ++__ds)

            {

                __hold.reset(__node_alloc_traits::allocate(__na, 1));

                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);

                __e.__ptr_->__next_ = __hold.get();

                __hold->__prev_ = __e.__ptr_;

                __hold.release();

            }

#ifndef _LIBCPP_NO_EXCEPTIONS

        }

        catch (...)

        {

            while (true)

            {

                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));

                __node_pointer __prev = __e.__ptr_->__prev_;

                __node_alloc_traits::deallocate(__na, __e.__ptr_, 1);

                if (__prev == 0)

                    break;

#if _LIBCPP_DEBUG_LEVEL >= 2

                __e = iterator(__prev, this);

#else

                __e = iterator(__prev);

#endif

            }

            throw;

        }

#endif  // _LIBCPP_NO_EXCEPTIONS

        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);

        base::__sz() += __ds;

    }

    return __r;

}

template <class _Tp, class _Alloc>

template <class _InpIter>

typename list<_Tp, _Alloc>::iterator

list<_Tp, _Alloc>::insert(const_iterator __p, _InpIter __f, _InpIter __l,

             typename enable_if<__is_input_iterator<_InpIter>::value>::type*)

{

#if _LIBCPP_DEBUG_LEVEL >= 2

    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,

        "list::insert(iterator, range) called with an iterator not"

        " referring to this list");

    iterator __r(__p.__ptr_, this);

#else

    iterator __r(__p.__ptr_);

#endif

    if (__f != __l)

    {

        size_type __ds = 0;

        __node_allocator& __na = base::__node_alloc();

        typedef __allocator_destructor<__node_allocator> _Dp;

        unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

        __hold->__prev_ = 0;

        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);

        ++__ds;

#if _LIBCPP_DEBUG_LEVEL >= 2

        __r = iterator(__hold.get(), this);

#else

        __r = iterator(__hold.get());

#endif

        __hold.release();

        iterator __e = __r;

#ifndef _LIBCPP_NO_EXCEPTIONS

        try

        {

#endif  // _LIBCPP_NO_EXCEPTIONS

            for (++__f; __f != __l; ++__f, (void) ++__e, (void) ++__ds)

            {

                __hold.reset(__node_alloc_traits::allocate(__na, 1));

                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);

                __e.__ptr_->__next_ = __hold.get();

                __hold->__prev_ = __e.__ptr_;

                __hold.release();

            }

#ifndef _LIBCPP_NO_EXCEPTIONS

        }

        catch (...)

        {

            while (true)

            {

                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));

                __node_pointer __prev = __e.__ptr_->__prev_;

                __node_alloc_traits::deallocate(__na, __e.__ptr_, 1);

                if (__prev == 0)

                    break;

#if _LIBCPP_DEBUG_LEVEL >= 2

                __e = iterator(__prev, this);

#else

                __e = iterator(__prev);

#endif

            }

            throw;

        }

#endif  // _LIBCPP_NO_EXCEPTIONS

        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);

        base::__sz() += __ds;

    }

    return __r;

}

template <class _Tp, class _Alloc>

void

list<_Tp, _Alloc>::push_front(const value_type& __x)

{

    __node_allocator& __na = base::__node_alloc();

    typedef __allocator_destructor<__node_allocator> _Dp;

    unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);

    __link_nodes_at_front(__hold.get(), __hold.get());

    ++base::__sz();

    __hold.release();

}

template <class _Tp, class _Alloc>

void

list<_Tp, _Alloc>::push_back(const value_type& __x)

{

    __node_allocator& __na = base::__node_alloc();

    typedef __allocator_destructor<__node_allocator> _Dp;

    unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);

    __link_nodes_at_back(__hold.get(), __hold.get());

    ++base::__sz();

    __hold.release();

}

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

template <class _Tp, class _Alloc>

void

list<_Tp, _Alloc>::push_front(value_type&& __x)

{

    __node_allocator& __na = base::__node_alloc();

    typedef __allocator_destructor<__node_allocator> _Dp;

    unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));

    __link_nodes_at_front(__hold.get(), __hold.get());

    ++base::__sz();

    __hold.release();

}

template <class _Tp, class _Alloc>

void

list<_Tp, _Alloc>::push_back(value_type&& __x)

{

    __node_allocator& __na = base::__node_alloc();

    typedef __allocator_destructor<__node_allocator> _Dp;

    unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));

    __link_nodes_at_back(__hold.get(), __hold.get());

    ++base::__sz();

    __hold.release();

}

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <class _Tp, class _Alloc>

template <class... _Args>

void

list<_Tp, _Alloc>::emplace_front(_Args&&... __args)

{

    __node_allocator& __na = base::__node_alloc();

    typedef __allocator_destructor<__node_allocator> _Dp;

    unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);

    __link_nodes_at_front(__hold.get(), __hold.get());

    ++base::__sz();

    __hold.release();

}

template <class _Tp, class _Alloc>

template <class... _Args>

void

list<_Tp, _Alloc>::emplace_back(_Args&&... __args)

{

    __node_allocator& __na = base::__node_alloc();

    typedef __allocator_destructor<__node_allocator> _Dp;

    unique_ptr<__node, _Dp> __hold(__node_alloc_traits::allocate(__na, 1), _Dp(__na, 1));

    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);

    __link_nodes_at_back(__hold.get(), __hold.get());

    ++base::__sz();

    __hold.release();

}

template <class _Tp, class _Alloc>

template <class... _Args>