include/list

// -*- 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>
 reference emplace_front(Args&&... args);
 void pop_front();
 template <class... Args>
 reference 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 <type_traits>

#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;

template <class _Tp, class _VoidPtr>
struct __list_node_pointer_traits {
 typedef typename __rebind_pointer<_VoidPtr, __list_node<_Tp, _VoidPtr> >::type
 __node_pointer;
 typedef typename __rebind_pointer<_VoidPtr, __list_node_base<_Tp, _VoidPtr> >::type
 __base_pointer;

#if defined(_LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB)
 typedef __base_pointer __link_pointer;
#else
 typedef typename conditional<
 is_pointer<_VoidPtr>::value,
 __base_pointer,
 __node_pointer
 >::type __link_pointer;
#endif

 typedef typename conditional<
 is_same<__link_pointer, __node_pointer>::value,
 __base_pointer,
 __node_pointer
 >::type __non_link_pointer;

 static _LIBCPP_INLINE_VISIBILITY
 __link_pointer __unsafe_link_pointer_cast(__link_pointer __p) {
 return __p;
 }

 static _LIBCPP_INLINE_VISIBILITY
 __link_pointer __unsafe_link_pointer_cast(__non_link_pointer __p) {
 return static_cast<__link_pointer>(static_cast<_VoidPtr>(__p));
 }

};

template <class _Tp, class _VoidPtr>
struct __list_node_base
{
 typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
 typedef typename _NodeTraits::__node_pointer __node_pointer;
 typedef typename _NodeTraits::__base_pointer __base_pointer;
 typedef typename _NodeTraits::__link_pointer __link_pointer;

 __link_pointer __prev_;
 __link_pointer __next_;

 _LIBCPP_INLINE_VISIBILITY
 __list_node_base() : __prev_(_NodeTraits::__unsafe_link_pointer_cast(__self())),
 __next_(_NodeTraits::__unsafe_link_pointer_cast(__self())) {}

 _LIBCPP_INLINE_VISIBILITY
 __base_pointer __self() {
 return pointer_traits<__base_pointer>::pointer_to(*this);
 }

 _LIBCPP_INLINE_VISIBILITY
 __node_pointer __as_node() {
 return static_cast<__node_pointer>(__self());
 }
};

template <class _Tp, class _VoidPtr>
struct __list_node
 : public __list_node_base<_Tp, _VoidPtr>
{
 _Tp __value_;

 typedef __list_node_base<_Tp, _VoidPtr> __base;
 typedef typename __base::__link_pointer __link_pointer;

 _LIBCPP_INLINE_VISIBILITY
 __link_pointer __as_link() {
 return static_cast<__link_pointer>(__base::__self());
 }
};

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 __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
 typedef typename _NodeTraits::__link_pointer __link_pointer;

 __link_pointer __ptr_;

#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_INLINE_VISIBILITY
 explicit __list_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
 : __ptr_(__p)
 {
 __get_db()->__insert_ic(this, __c);
 }
#else
 _LIBCPP_INLINE_VISIBILITY
 explicit __list_iterator(__link_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 __rebind_pointer<_VoidPtr, value_type>::type 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_->__as_node()->__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_->__as_node()->__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 __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
 typedef typename _NodeTraits::__link_pointer __link_pointer;

 __link_pointer __ptr_;

#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_INLINE_VISIBILITY
 explicit __list_const_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
 : __ptr_(__p)
 {
 __get_db()->__insert_ic(this, __c);
 }
#else
 _LIBCPP_INLINE_VISIBILITY
 explicit __list_const_iterator(__link_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 __rebind_pointer<_VoidPtr, const value_type>::type 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_->__as_node()->__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_->__as_node()->__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 __list_node_pointer_traits<value_type, __void_pointer> __node_pointer_traits;
 typedef typename __node_pointer_traits::__link_pointer __link_pointer;
 typedef __link_pointer __link_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
 __link_pointer __end_as_link() const _NOEXCEPT {
 return __node_pointer_traits::__unsafe_link_pointer_cast(
 const_cast<__node_base&>(__end_).__self());
 }

 _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();}

 _LIBCPP_INLINE_VISIBILITY
 size_type __node_alloc_max_size() const _NOEXCEPT {
 return __node_alloc_traits::max_size(__node_alloc());
 }
 _LIBCPP_INLINE_VISIBILITY
 static void __unlink_nodes(__link_pointer __f, __link_pointer __l) _NOEXCEPT;

 _LIBCPP_INLINE_VISIBILITY
 __list_imp()
 _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value);
 _LIBCPP_INLINE_VISIBILITY
 __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(__end_as_link(), this);
#else
 return iterator(__end_as_link());
#endif
 }
 _LIBCPP_INLINE_VISIBILITY
 const_iterator end() const _NOEXCEPT
 {
#if _LIBCPP_DEBUG_LEVEL >= 2
 return const_iterator(__end_as_link(), this);
#else
 return const_iterator(__end_as_link());
#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
void
__list_imp<_Tp, _Alloc>::__unlink_nodes(__link_pointer __f, __link_pointer __l)
 _NOEXCEPT
{
 __f->__prev_->__next_ = __l->__next_;
 __l->__next_->__prev_ = __f->__prev_;
}

template <class _Tp, class _Alloc>
inline
__list_imp<_Tp, _Alloc>::__list_imp()
 _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
 : __size_alloc_(0)
{
}

template <class _Tp, class _Alloc>
inline
__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();
 __link_pointer __f = __end_.__next_;
 __link_pointer __l = __end_as_link();
 __unlink_nodes(__f, __l->__prev_);
 __sz() = 0;
 while (__f != __l)
 {
 __node_pointer __np = __f->__as_node();
 __f = __f->__next_;
 __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
 __node_alloc_traits::deallocate(__na, __np, 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_as_link();
 else
 __end_.__prev_->__next_ = __end_.__next_->__prev_ = __end_as_link();
 if (__c.__sz() == 0)
 __c.__end_.__next_ = __c.__end_.__prev_ = __c.__end_as_link();
 else
 __c.__end_.__prev_->__next_ = __c.__end_.__next_->__prev_ = __c.__end_as_link();

#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_ == __c.__end_as_link())
 {
 __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_ == __end_as_link())
 {
 __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;
 typedef typename base::__link_pointer __link_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);
 _LIBCPP_INLINE_VISIBILITY
 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
 _LIBCPP_INLINE_VISIBILITY
 list(list&& __c)
 _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
 _LIBCPP_INLINE_VISIBILITY
 list(list&& __c, const allocator_type& __a);
 _LIBCPP_INLINE_VISIBILITY
 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

 _LIBCPP_INLINE_VISIBILITY
 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 std::min<size_type>(
 base::__node_alloc_max_size(),
 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_->__as_node()->__value_;
 }
 _LIBCPP_INLINE_VISIBILITY
 const_reference front() const
 {
 _LIBCPP_ASSERT(!empty(), "list::front called on empty list");
 return base::__end_.__next_->__as_node()->__value_;
 }
 _LIBCPP_INLINE_VISIBILITY
 reference back()
 {
 _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
 return base::__end_.__prev_->__as_node()->__value_;
 }
 _LIBCPP_INLINE_VISIBILITY
 const_reference back() const
 {
 _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
 return base::__end_.__prev_->__as_node()->__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>
 reference emplace_front(_Args&&... __args);
 template <class... _Args>
 reference 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);
 _LIBCPP_INLINE_VISIBILITY
 void unique();
 template <class _BinaryPred>
 void unique(_BinaryPred __binary_pred);
 _LIBCPP_INLINE_VISIBILITY
 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
 _LIBCPP_INLINE_VISIBILITY
 void sort();
 template <class _Comp>
 _LIBCPP_INLINE_VISIBILITY
 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:
 _LIBCPP_INLINE_VISIBILITY
 static void __link_nodes (__link_pointer __p, __link_pointer __f, __link_pointer __l);
 _LIBCPP_INLINE_VISIBILITY
 void __link_nodes_at_front(__link_pointer __f, __link_pointer __l);
 _LIBCPP_INLINE_VISIBILITY
 void __link_nodes_at_back (__link_pointer __f, __link_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
void
list<_Tp, _Alloc>::__link_nodes(__link_pointer __p, __link_pointer __f, __link_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
void
list<_Tp, _Alloc>::__link_nodes_at_front(__link_pointer __f, __link_pointer __l)
{
 __f->__prev_ = base::__end_as_link();
 __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
void
list<_Tp, _Alloc>::__link_nodes_at_back(__link_pointer __f, __link_pointer __l)
{
 __l->__next_ = base::__end_as_link();
 __f->__prev_ = base::__end_.__prev_;
 __f->__prev_->__next_ = __f;
 base::__end_.__prev_ = __l;
}


template <class _Tp, class _Alloc>
inline
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
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
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
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
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
_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->__as_link(), __hold->__as_link());
 ++base::__sz();
#if _LIBCPP_DEBUG_LEVEL >= 2
 return iterator(__hold.release()->__as_link(), this);
#else
 return iterator(__hold.release()->__as_link());
#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->__as_link(), this);
#else
 __r = iterator(__hold->__as_link());
#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->__as_link();
 __hold->__prev_ = __e.__ptr_;
 __hold.release();
 }
#ifndef _LIBCPP_NO_EXCEPTIONS
 }
 catch (...)
 {
 while (true)
 {
 __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
 __link_pointer __prev = __e.__ptr_->__prev_;
 __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 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()->__as_link(), this);
#else
 __r = iterator(__hold.get()->__as_link());
#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()->__as_link();
 __hold->__prev_ = __e.__ptr_;
 __hold.release();
 }
#ifndef _LIBCPP_NO_EXCEPTIONS
 }
 catch (...)
 {
 while (true)
 {
 __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
 __link_pointer __prev = __e.__ptr_->__prev_;
 __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 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_pointer __nl = __hold->__as_link();
 __link_nodes_at_front(__nl, __nl);
 ++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()->__as_link(), __hold.get()->__as_link());
 ++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()->__as_link(), __hold.get()->__as_link());
 ++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()->__as_link(), __hold.get()->__as_link());
 ++base::__sz();
 __hold.release();
}

#ifndef _LIBCPP_HAS_NO_VARIADICS

template <class _Tp, class _Alloc>
template <class... _Args>
typename list<_Tp, _Alloc>::reference
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()->__as_link(), __hold.get()->__as_link());
 ++base::__sz();
 return __hold.release()->__value_;
}

template <class _Tp, class _Alloc>
template <class... _Args>
typename list<_Tp, _Alloc>::reference
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_pointer __nl = __hold->__as_link();
 __link_nodes_at_back(__nl, __nl);
 ++base::__sz();
 return __hold.release()->__value_;
}

template <class _Tp, class _Alloc>
template <class... _Args>
typename list<_Tp, _Alloc>::iterator
list<_Tp, _Alloc>::emplace(const_iterator __p, _Args&&... __args)
{
#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
 "list::emplace(iterator, args...) 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_), _VSTD::forward<_Args>(__args)...);
 __link_pointer __nl = __hold.get()->__as_link();
 __link_nodes(__p.__ptr_, __nl, __nl);
 ++base::__sz();
 __hold.release();
#if _LIBCPP_DEBUG_LEVEL >= 2
 return iterator(__nl, this);
#else
 return iterator(__nl);
#endif
}

#endif // _LIBCPP_HAS_NO_VARIADICS

template <class _Tp, class _Alloc>
typename list<_Tp, _Alloc>::iterator
list<_Tp, _Alloc>::insert(const_iterator __p, 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_), _VSTD::move(__x));
 __link_pointer __nl = __hold->__as_link();
 __link_nodes(__p.__ptr_, __nl, __nl);
 ++base::__sz();
 __hold.release();
#if _LIBCPP_DEBUG_LEVEL >= 2
 return iterator(__nl, this);
#else
 return iterator(__nl);
#endif
}

#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::pop_front()
{
 _LIBCPP_ASSERT(!empty(), "list::pop_front() called with empty list");
 __node_allocator& __na = base::__node_alloc();
 __link_pointer __n = base::__end_.__next_;
 base::__unlink_nodes(__n, __n);
 --base::__sz();
#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;
 iterator* __i = static_cast<iterator*>((*__p)->__i_);
 if (__i->__ptr_ == __n)
 {
 (*__p)->__c_ = nullptr;
 if (--__c->end_ != __p)
 memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
 }
 }
 __get_db()->unlock();
#endif
 __node_pointer __np = __n->__as_node();
 __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
 __node_alloc_traits::deallocate(__na, __np, 1);
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::pop_back()
{
 _LIBCPP_ASSERT(!empty(), "list::pop_back() called with empty list");
 __node_allocator& __na = base::__node_alloc();
 __link_pointer __n = base::__end_.__prev_;
 base::__unlink_nodes(__n, __n);
 --base::__sz();
#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;
 iterator* __i = static_cast<iterator*>((*__p)->__i_);
 if (__i->__ptr_ == __n)
 {
 (*__p)->__c_ = nullptr;
 if (--__c->end_ != __p)
 memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
 }
 }
 __get_db()->unlock();
#endif
 __node_pointer __np = __n->__as_node();
 __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
 __node_alloc_traits::deallocate(__na, __np, 1);
}

template <class _Tp, class _Alloc>
typename list<_Tp, _Alloc>::iterator
list<_Tp, _Alloc>::erase(const_iterator __p)
{
#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
 "list::erase(iterator) called with an iterator not"
 " referring to this list");
#endif
 _LIBCPP_ASSERT(__p != end(),
 "list::erase(iterator) called with a non-dereferenceable iterator");
 __node_allocator& __na = base::__node_alloc();
 __link_pointer __n = __p.__ptr_;
 __link_pointer __r = __n->__next_;
 base::__unlink_nodes(__n, __n);
 --base::__sz();
#if _LIBCPP_DEBUG_LEVEL >= 2
 __c_node* __c = __get_db()->__find_c_and_lock(this);
 for (__i_node** __ip = __c->end_; __ip != __c->beg_; )
 {
 --__ip;
 iterator* __i = static_cast<iterator*>((*__ip)->__i_);
 if (__i->__ptr_ == __n)
 {
 (*__ip)->__c_ = nullptr;
 if (--__c->end_ != __ip)
 memmove(__ip, __ip+1, (__c->end_ - __ip)*sizeof(__i_node*));
 }
 }
 __get_db()->unlock();
#endif
 __node_pointer __np = __n->__as_node();
 __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
 __node_alloc_traits::deallocate(__na, __np, 1);
#if _LIBCPP_DEBUG_LEVEL >= 2
 return iterator(__r, this);
#else
 return iterator(__r);
#endif
}

template <class _Tp, class _Alloc>
typename list<_Tp, _Alloc>::iterator
list<_Tp, _Alloc>::erase(const_iterator __f, const_iterator __l)
{
#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__f) == this,
 "list::erase(iterator, iterator) called with an iterator not"
 " referring to this list");
#endif
 if (__f != __l)
 {
 __node_allocator& __na = base::__node_alloc();
 base::__unlink_nodes(__f.__ptr_, __l.__ptr_->__prev_);
 while (__f != __l)
 {
 __link_pointer __n = __f.__ptr_;
 ++__f;
 --base::__sz();
#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;
 iterator* __i = static_cast<iterator*>((*__p)->__i_);
 if (__i->__ptr_ == __n)
 {
 (*__p)->__c_ = nullptr;
 if (--__c->end_ != __p)
 memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
 }
 }
 __get_db()->unlock();
#endif
 __node_pointer __np = __n->__as_node();
 __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
 __node_alloc_traits::deallocate(__na, __np, 1);
 }
 }
#if _LIBCPP_DEBUG_LEVEL >= 2
 return iterator(__l.__ptr_, this);
#else
 return iterator(__l.__ptr_);
#endif
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::resize(size_type __n)
{
 if (__n < base::__sz())
 erase(__iterator(__n), end());
 else if (__n > base::__sz())
 {
 __n -= base::__sz();
 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_));
 ++__ds;
#if _LIBCPP_DEBUG_LEVEL >= 2
 iterator __r = iterator(__hold.release()->__as_link(), this);
#else
 iterator __r = iterator(__hold.release()->__as_link());
#endif
 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_));
 __e.__ptr_->__next_ = __hold.get()->__as_link();
 __hold->__prev_ = __e.__ptr_;
 __hold.release();
 }
#ifndef _LIBCPP_NO_EXCEPTIONS
 }
 catch (...)
 {
 while (true)
 {
 __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
 __link_pointer __prev = __e.__ptr_->__prev_;
 __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 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_at_back(__r.__ptr_, __e.__ptr_);
 base::__sz() += __ds;
 }
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::resize(size_type __n, const value_type& __x)
{
 if (__n < base::__sz())
 erase(__iterator(__n), end());
 else if (__n > base::__sz())
 {
 __n -= base::__sz();
 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;
 __link_pointer __nl = __hold.release()->__as_link();
#if _LIBCPP_DEBUG_LEVEL >= 2
 iterator __r = iterator(__nl, this);
#else
 iterator __r = iterator(__nl);
#endif
 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()->__as_link();
 __hold->__prev_ = __e.__ptr_;
 __hold.release();
 }
#ifndef _LIBCPP_NO_EXCEPTIONS
 }
 catch (...)
 {
 while (true)
 {
 __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
 __link_pointer __prev = __e.__ptr_->__prev_;
 __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 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(base::__end_as_link(), __r.__ptr_, __e.__ptr_);
 base::__sz() += __ds;
 }
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::splice(const_iterator __p, list& __c)
{
 _LIBCPP_ASSERT(this != &__c,
 "list::splice(iterator, list) called with this == &list");
#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
 "list::splice(iterator, list) called with an iterator not"
 " referring to this list");
#endif
 if (!__c.empty())
 {
 __link_pointer __f = __c.__end_.__next_;
 __link_pointer __l = __c.__end_.__prev_;
 base::__unlink_nodes(__f, __l);
 __link_nodes(__p.__ptr_, __f, __l);
 base::__sz() += __c.__sz();
 __c.__sz() = 0;
#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);
 for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
 {
 --__ip;
 iterator* __i = static_cast<iterator*>((*__ip)->__i_);
 if (__i->__ptr_ != __c.__end_as_link())
 {
 __cn1->__add(*__ip);
 (*__ip)->__c_ = __cn1;
 if (--__cn2->end_ != __ip)
 memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
 }
 }
 __db->unlock();
#endif
 }
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __i)
{
#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
 "list::splice(iterator, list, iterator) called with first iterator not"
 " referring to this list");
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__i) == &__c,
 "list::splice(iterator, list, iterator) called with second iterator not"
 " referring to list argument");
 _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(&__i),
 "list::splice(iterator, list, iterator) called with second iterator not"
 " derefereceable");
#endif
 if (__p.__ptr_ != __i.__ptr_ && __p.__ptr_ != __i.__ptr_->__next_)
 {
 __link_pointer __f = __i.__ptr_;
 base::__unlink_nodes(__f, __f);
 __link_nodes(__p.__ptr_, __f, __f);
 --__c.__sz();
 ++base::__sz();
#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);
 for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
 {
 --__ip;
 iterator* __j = static_cast<iterator*>((*__ip)->__i_);
 if (__j->__ptr_ == __f)
 {
 __cn1->__add(*__ip);
 (*__ip)->__c_ = __cn1;
 if (--__cn2->end_ != __ip)
 memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
 }
 }
 __db->unlock();
#endif
 }
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l)
{
#if _LIBCPP_DEBUG_LEVEL >= 2
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
 "list::splice(iterator, list, iterator, iterator) called with first iterator not"
 " referring to this list");
 _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__f) == &__c,
 "list::splice(iterator, list, iterator, iterator) called with second iterator not"
 " referring to list argument");
 if (this == &__c)
 {
 for (const_iterator __i = __f; __i != __l; ++__i)
 _LIBCPP_ASSERT(__i != __p,
 "list::splice(iterator, list, iterator, iterator)"
 " called with the first iterator within the range"
 " of the second and third iterators");
 }
#endif
 if (__f != __l)
 {
 if (this != &__c)
 {
 size_type __s = _VSTD::distance(__f, __l);
 __c.__sz() -= __s;
 base::__sz() += __s;
 }
 __link_pointer __first = __f.__ptr_;
 --__l;
 __link_pointer __last = __l.__ptr_;
 base::__unlink_nodes(__first, __last);
 __link_nodes(__p.__ptr_, __first, __last);
#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);
 for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
 {
 --__ip;
 iterator* __j = static_cast<iterator*>((*__ip)->__i_);
 for (__link_pointer __k = __f.__ptr_;
 __k != __l.__ptr_; __k = __k->__next_)
 {
 if (__j->__ptr_ == __k)
 {
 __cn1->__add(*__ip);
 (*__ip)->__c_ = __cn1;
 if (--__cn2->end_ != __ip)
 memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
 }
 }
 }
 __db->unlock();
#endif
 }
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::remove(const value_type& __x)
{
 list<_Tp, _Alloc> __deleted_nodes; // collect the nodes we're removing
 for (const_iterator __i = begin(), __e = end(); __i != __e;)
 {
 if (*__i == __x)
 {
 const_iterator __j = _VSTD::next(__i);
 for (; __j != __e && *__j == __x; ++__j)
 ;
 __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
 __i = __j;
 if (__i != __e)
 ++__i;
 }
 else
 ++__i;
 }
}

template <class _Tp, class _Alloc>
template <class _Pred>
void
list<_Tp, _Alloc>::remove_if(_Pred __pred)
{
 for (iterator __i = begin(), __e = end(); __i != __e;)
 {
 if (__pred(*__i))
 {
 iterator __j = _VSTD::next(__i);
 for (; __j != __e && __pred(*__j); ++__j)
 ;
 __i = erase(__i, __j);
 if (__i != __e)
 ++__i;
 }
 else
 ++__i;
 }
}

template <class _Tp, class _Alloc>
inline
void
list<_Tp, _Alloc>::unique()
{
 unique(__equal_to<value_type>());
}

template <class _Tp, class _Alloc>
template <class _BinaryPred>
void
list<_Tp, _Alloc>::unique(_BinaryPred __binary_pred)
{
 for (iterator __i = begin(), __e = end(); __i != __e;)
 {
 iterator __j = _VSTD::next(__i);
 for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
 ;
 if (++__i != __j)
 __i = erase(__i, __j);
 }
}

template <class _Tp, class _Alloc>
inline
void
list<_Tp, _Alloc>::merge(list& __c)
{
 merge(__c, __less<value_type>());
}

template <class _Tp, class _Alloc>
template <class _Comp>
void
list<_Tp, _Alloc>::merge(list& __c, _Comp __comp)
{
 if (this != &__c)
 {
 iterator __f1 = begin();
 iterator __e1 = end();
 iterator __f2 = __c.begin();
 iterator __e2 = __c.end();
 while (__f1 != __e1 && __f2 != __e2)
 {
 if (__comp(*__f2, *__f1))
 {
 size_type __ds = 1;
 iterator __m2 = _VSTD::next(__f2);
 for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, ++__ds)
 ;
 base::__sz() += __ds;
 __c.__sz() -= __ds;
 __link_pointer __f = __f2.__ptr_;
 __link_pointer __l = __m2.__ptr_->__prev_;
 __f2 = __m2;
 base::__unlink_nodes(__f, __l);
 __m2 = _VSTD::next(__f1);
 __link_nodes(__f1.__ptr_, __f, __l);
 __f1 = __m2;
 }
 else
 ++__f1;
 }
 splice(__e1, __c);
#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);
 for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)
 {
 --__p;
 iterator* __i = static_cast<iterator*>((*__p)->__i_);
 if (__i->__ptr_ != __c.__end_as_link())
 {
 __cn1->__add(*__p);
 (*__p)->__c_ = __cn1;
 if (--__cn2->end_ != __p)
 memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));
 }
 }
 __db->unlock();
#endif
 }
}

template <class _Tp, class _Alloc>
inline
void
list<_Tp, _Alloc>::sort()
{
 sort(__less<value_type>());
}

template <class _Tp, class _Alloc>
template <class _Comp>
inline
void
list<_Tp, _Alloc>::sort(_Comp __comp)
{
 __sort(begin(), end(), base::__sz(), __comp);
}

template <class _Tp, class _Alloc>
template <class _Comp>
typename list<_Tp, _Alloc>::iterator
list<_Tp, _Alloc>::__sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp)
{
 switch (__n)
 {
 case 0:
 case 1:
 return __f1;
 case 2:
 if (__comp(*--__e2, *__f1))
 {
 __link_pointer __f = __e2.__ptr_;
 base::__unlink_nodes(__f, __f);
 __link_nodes(__f1.__ptr_, __f, __f);
 return __e2;
 }
 return __f1;
 }
 size_type __n2 = __n / 2;
 iterator __e1 = _VSTD::next(__f1, __n2);
 iterator __r = __f1 = __sort(__f1, __e1, __n2, __comp);
 iterator __f2 = __e1 = __sort(__e1, __e2, __n - __n2, __comp);
 if (__comp(*__f2, *__f1))
 {
 iterator __m2 = _VSTD::next(__f2);
 for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
 ;
 __link_pointer __f = __f2.__ptr_;
 __link_pointer __l = __m2.__ptr_->__prev_;
 __r = __f2;
 __e1 = __f2 = __m2;
 base::__unlink_nodes(__f, __l);
 __m2 = _VSTD::next(__f1);
 __link_nodes(__f1.__ptr_, __f, __l);
 __f1 = __m2;
 }
 else
 ++__f1;
 while (__f1 != __e1 && __f2 != __e2)
 {
 if (__comp(*__f2, *__f1))
 {
 iterator __m2 = _VSTD::next(__f2);
 for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
 ;
 __link_pointer __f = __f2.__ptr_;
 __link_pointer __l = __m2.__ptr_->__prev_;
 if (__e1 == __f2)
 __e1 = __m2;
 __f2 = __m2;
 base::__unlink_nodes(__f, __l);
 __m2 = _VSTD::next(__f1);
 __link_nodes(__f1.__ptr_, __f, __l);
 __f1 = __m2;
 }
 else
 ++__f1;
 }
 return __r;
}

template <class _Tp, class _Alloc>
void
list<_Tp, _Alloc>::reverse() _NOEXCEPT
{
 if (base::__sz() > 1)
 {
 iterator __e = end();
 for (iterator __i = begin(); __i.__ptr_ != __e.__ptr_;)
 {
 _VSTD::swap(__i.__ptr_->__prev_, __i.__ptr_->__next_);
 __i.__ptr_ = __i.__ptr_->__prev_;
 }
 _VSTD::swap(__e.__ptr_->__prev_, __e.__ptr_->__next_);
 }
}

template <class _Tp, class _Alloc>
bool
list<_Tp, _Alloc>::__invariants() const
{
 return size() == _VSTD::distance(begin(), end());
}

#if _LIBCPP_DEBUG_LEVEL >= 2

template <class _Tp, class _Alloc>
bool
list<_Tp, _Alloc>::__dereferenceable(const const_iterator* __i) const
{
 return __i->__ptr_ != this->__end_as_link();
}

template <class _Tp, class _Alloc>
bool
list<_Tp, _Alloc>::__decrementable(const const_iterator* __i) const
{
 return !empty() && __i->__ptr_ != base::__end_.__next_;
}

template <class _Tp, class _Alloc>
bool
list<_Tp, _Alloc>::__addable(const const_iterator* __i, ptrdiff_t __n) const
{
 return false;
}

template <class _Tp, class _Alloc>
bool
list<_Tp, _Alloc>::__subscriptable(const const_iterator* __i, ptrdiff_t __n) const
{
 return false;
}

#endif // _LIBCPP_DEBUG_LEVEL >= 2

template <class _Tp, class _Alloc>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
{
 return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
}

template <class _Tp, class _Alloc>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator< (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
{
 return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
}

template <class _Tp, class _Alloc>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
{
 return !(__x == __y);
}

template <class _Tp, class _Alloc>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator> (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
{
 return __y < __x;
}

template <class _Tp, class _Alloc>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
{
 return !(__x < __y);
}

template <class _Tp, class _Alloc>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
{
 return !(__y < __x);
}

template <class _Tp, class _Alloc>
inline _LIBCPP_INLINE_VISIBILITY
void
swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
 _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
{
 __x.swap(__y);
}

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_LIST