LCOM1920-T02G10

// -*- C++ -*-

//===-------------------------- iterator ----------------------------------===//

//

//                     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_ITERATOR

#define _LIBCPP_ITERATOR

/*

    iterator synopsis

namespace std

{

template<class Iterator>

struct iterator_traits

{

    typedef typename Iterator::difference_type difference_type;

    typedef typename Iterator::value_type value_type;

    typedef typename Iterator::pointer pointer;

    typedef typename Iterator::reference reference;

    typedef typename Iterator::iterator_category iterator_category;

};

template<class T>

struct iterator_traits<T*>

{

    typedef ptrdiff_t difference_type;

    typedef T value_type;

    typedef T* pointer;

    typedef T& reference;

    typedef random_access_iterator_tag iterator_category;

};

template<class T>

struct iterator_traits<const T*>

{

    typedef ptrdiff_t difference_type;

    typedef T value_type;

    typedef const T* pointer;

    typedef const T& reference;

    typedef random_access_iterator_tag iterator_category;

};

template<class Category, class T, class Distance = ptrdiff_t,

         class Pointer = T*, class Reference = T&>

struct iterator

{

    typedef T         value_type;

    typedef Distance  difference_type;

    typedef Pointer   pointer;

    typedef Reference reference;

    typedef Category  iterator_category;

};

struct input_iterator_tag  {};

struct output_iterator_tag {};

struct forward_iterator_tag       : public input_iterator_tag         {};

struct bidirectional_iterator_tag : public forward_iterator_tag       {};

struct random_access_iterator_tag : public bidirectional_iterator_tag {};

// extension: second argument not conforming to C++03

template <class InputIterator>

void advance(InputIterator& i,

             typename iterator_traits<InputIterator>::difference_type n);

template <class InputIterator>

typename iterator_traits<InputIterator>::difference_type

distance(InputIterator first, InputIterator last);

template <class Iterator>

class reverse_iterator

    : public iterator<typename iterator_traits<Iterator>::iterator_category,

                      typename iterator_traits<Iterator>::value_type,

                      typename iterator_traits<Iterator>::difference_type,

                      typename iterator_traits<Iterator>::pointer,

                      typename iterator_traits<Iterator>::reference>

{

protected:

    Iterator current;

public:

    typedef Iterator                                            iterator_type;

    typedef typename iterator_traits<Iterator>::difference_type difference_type;

    typedef typename iterator_traits<Iterator>::reference       reference;

    typedef typename iterator_traits<Iterator>::pointer         pointer;

    reverse_iterator();

    explicit reverse_iterator(Iterator x);

    template <class U> reverse_iterator(const reverse_iterator<U>& u);

    Iterator base() const;

    reference operator*() const;

    pointer   operator->() const;

    reverse_iterator& operator++();

    reverse_iterator  operator++(int);

    reverse_iterator& operator--();

    reverse_iterator  operator--(int);

    reverse_iterator  operator+ (difference_type n) const;

    reverse_iterator& operator+=(difference_type n);

    reverse_iterator  operator- (difference_type n) const;

    reverse_iterator& operator-=(difference_type n);

    reference         operator[](difference_type n) const;

};

template <class Iterator1, class Iterator2>

bool

operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);

template <class Iterator1, class Iterator2>

bool

operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);

template <class Iterator1, class Iterator2>

bool

operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);

template <class Iterator1, class Iterator2>

bool

operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);

template <class Iterator1, class Iterator2>

bool

operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);

template <class Iterator1, class Iterator2>

bool

operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);

template <class Iterator1, class Iterator2>

typename reverse_iterator<Iterator1>::difference_type

operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);

template <class Iterator>

reverse_iterator<Iterator>

operator+(typename reverse_iterator<Iterator>::difference_type n, const reverse_iterator<Iterator>& x);

template <class Iterator> reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14

template <class Container>

class back_insert_iterator

{

protected:

    Container* container;

public:

    typedef Container                   container_type;

    typedef void                        value_type;

    typedef void                        difference_type;

    typedef back_insert_iterator<Cont>& reference;

    typedef void                        pointer;

    explicit back_insert_iterator(Container& x);

    back_insert_iterator& operator=(const typename Container::value_type& value);

    back_insert_iterator& operator*();

    back_insert_iterator& operator++();

    back_insert_iterator  operator++(int);

};

template <class Container> back_insert_iterator<Container> back_inserter(Container& x);

template <class Container>

class front_insert_iterator

{

protected:

    Container* container;

public:

    typedef Container                    container_type;

    typedef void                         value_type;

    typedef void                         difference_type;

    typedef front_insert_iterator<Cont>& reference;

    typedef void                         pointer;

    explicit front_insert_iterator(Container& x);

    front_insert_iterator& operator=(const typename Container::value_type& value);

    front_insert_iterator& operator*();

    front_insert_iterator& operator++();

    front_insert_iterator  operator++(int);

};

template <class Container> front_insert_iterator<Container> front_inserter(Container& x);

template <class Container>

class insert_iterator

{

protected:

    Container* container;

    typename Container::iterator iter;

public:

    typedef Container              container_type;

    typedef void                   value_type;

    typedef void                   difference_type;

    typedef insert_iterator<Cont>& reference;

    typedef void                   pointer;

    insert_iterator(Container& x, typename Container::iterator i);

    insert_iterator& operator=(const typename Container::value_type& value);

    insert_iterator& operator*();

    insert_iterator& operator++();

    insert_iterator& operator++(int);

};

template <class Container, class Iterator>

insert_iterator<Container> inserter(Container& x, Iterator i);

template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>

class istream_iterator

    : public iterator<input_iterator_tag, T, Distance, const T*, const T&>

{

public:

    typedef charT char_type;

    typedef traits traits_type;

    typedef basic_istream<charT,traits> istream_type;

    constexpr istream_iterator();

    istream_iterator(istream_type& s);

    istream_iterator(const istream_iterator& x);

    ~istream_iterator();

    const T& operator*() const;

    const T* operator->() const;

    istream_iterator& operator++();

    istream_iterator  operator++(int);

};

template <class T, class charT, class traits, class Distance>

bool operator==(const istream_iterator<T,charT,traits,Distance>& x,

                const istream_iterator<T,charT,traits,Distance>& y);

template <class T, class charT, class traits, class Distance>

bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,

                const istream_iterator<T,charT,traits,Distance>& y);

template <class T, class charT = char, class traits = char_traits<charT> >

class ostream_iterator

    : public iterator<output_iterator_tag, void, void, void ,void>

{

public:

    typedef charT char_type;

    typedef traits traits_type;

    typedef basic_ostream<charT,traits> ostream_type;

    ostream_iterator(ostream_type& s);

    ostream_iterator(ostream_type& s, const charT* delimiter);

    ostream_iterator(const ostream_iterator& x);

    ~ostream_iterator();

    ostream_iterator& operator=(const T& value);

    ostream_iterator& operator*();

    ostream_iterator& operator++();

    ostream_iterator& operator++(int);

};

template<class charT, class traits = char_traits<charT> >

class istreambuf_iterator

    : public iterator<input_iterator_tag, charT,

                      typename traits::off_type, unspecified,

                      charT>

{

public:

    typedef charT                         char_type;

    typedef traits                        traits_type;

    typedef typename traits::int_type     int_type;

    typedef basic_streambuf<charT,traits> streambuf_type;

    typedef basic_istream<charT,traits>   istream_type;

    istreambuf_iterator() noexcept;

    istreambuf_iterator(istream_type& s) noexcept;

    istreambuf_iterator(streambuf_type* s) noexcept;

    istreambuf_iterator(a-private-type) noexcept;

    charT                operator*() const;

    pointer operator->() const;

    istreambuf_iterator& operator++();

    a-private-type       operator++(int);

    bool equal(const istreambuf_iterator& b) const;

};

template <class charT, class traits>

bool operator==(const istreambuf_iterator<charT,traits>& a,

                const istreambuf_iterator<charT,traits>& b);

template <class charT, class traits>

bool operator!=(const istreambuf_iterator<charT,traits>& a,

                const istreambuf_iterator<charT,traits>& b);

template <class charT, class traits = char_traits<charT> >

class ostreambuf_iterator

    : public iterator<output_iterator_tag, void, void, void, void>

{

public:

    typedef charT                         char_type;

    typedef traits                        traits_type;

    typedef basic_streambuf<charT,traits> streambuf_type;

    typedef basic_ostream<charT,traits>   ostream_type;

    ostreambuf_iterator(ostream_type& s) noexcept;

    ostreambuf_iterator(streambuf_type* s) noexcept;

    ostreambuf_iterator& operator=(charT c);

    ostreambuf_iterator& operator*();

    ostreambuf_iterator& operator++();

    ostreambuf_iterator& operator++(int);

    bool failed() const noexcept;

};

template <class C> auto begin(C& c) -> decltype(c.begin());

template <class C> auto begin(const C& c) -> decltype(c.begin());

template <class C> auto end(C& c) -> decltype(c.end());

template <class C> auto end(const C& c) -> decltype(c.end());

template <class T, size_t N> T* begin(T (&array)[N]);

template <class T, size_t N> T* end(T (&array)[N]);

template <class C> auto cbegin(const C& c) -> decltype(std::begin(c));        // C++14

template <class C> auto cend(const C& c) -> decltype(std::end(c));            // C++14

template <class C> auto rbegin(C& c) -> decltype(c.rbegin());                 // C++14

template <class C> auto rbegin(const C& c) -> decltype(c.rbegin());           // C++14

template <class C> auto rend(C& c) -> decltype(c.rend());                     // C++14

template <class C> auto rend(const C& c) -> decltype(c.rend());               // C++14

template <class E> reverse_iterator<const E*> rbegin(initializer_list<E> il); // C++14

template <class E> reverse_iterator<const E*> rend(initializer_list<E> il);   // C++14

template <class T, size_t N> reverse_iterator<T*> rbegin(T (&array)[N]);      // C++14

template <class T, size_t N> reverse_iterator<T*> rend(T (&array)[N]);        // C++14

template <class C> auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14

template <class C> auto crend(const C& c) -> decltype(std::rend(c));          // C++14

// 24.8, container access:

template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17

template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17

template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17

template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17

template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17

template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17

template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17

template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17

template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17

}  // std

*/

#include <__config>

#include <__functional_base>

#include <type_traits>

#include <cstddef>

#include <iosfwd>

#include <initializer_list>

#ifdef __APPLE__

#include <Availability.h>

#endif

#include <__debug>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)

#pragma GCC system_header

#endif

_LIBCPP_BEGIN_NAMESPACE_STD

struct _LIBCPP_TYPE_VIS_ONLY input_iterator_tag {};

struct _LIBCPP_TYPE_VIS_ONLY output_iterator_tag {};

struct _LIBCPP_TYPE_VIS_ONLY forward_iterator_tag       : public input_iterator_tag {};

struct _LIBCPP_TYPE_VIS_ONLY bidirectional_iterator_tag : public forward_iterator_tag {};

struct _LIBCPP_TYPE_VIS_ONLY random_access_iterator_tag : public bidirectional_iterator_tag {};

template <class _Tp>

struct __has_iterator_category

{

private:

    struct __two {char __lx; char __lxx;};

    template <class _Up> static __two __test(...);

    template <class _Up> static char __test(typename _Up::iterator_category* = 0);

public:

    static const bool value = sizeof(__test<_Tp>(0)) == 1;

};

template <class _Iter, bool> struct __iterator_traits_impl {};

template <class _Iter>

struct __iterator_traits_impl<_Iter, true>

{

    typedef typename _Iter::difference_type   difference_type;

    typedef typename _Iter::value_type        value_type;

    typedef typename _Iter::pointer           pointer;

    typedef typename _Iter::reference         reference;

    typedef typename _Iter::iterator_category iterator_category;

};

template <class _Iter, bool> struct __iterator_traits {};

template <class _Iter>

struct __iterator_traits<_Iter, true>

    :  __iterator_traits_impl

      <

        _Iter,

        is_convertible<typename _Iter::iterator_category, input_iterator_tag>::value ||

        is_convertible<typename _Iter::iterator_category, output_iterator_tag>::value

      >

{};

// iterator_traits<Iterator> will only have the nested types if Iterator::iterator_category

//    exists.  Else iterator_traits<Iterator> will be an empty class.  This is a

//    conforming extension which allows some programs to compile and behave as

//    the client expects instead of failing at compile time.

template <class _Iter>

struct _LIBCPP_TYPE_VIS_ONLY iterator_traits

    : __iterator_traits<_Iter, __has_iterator_category<_Iter>::value> {};

template<class _Tp>

struct _LIBCPP_TYPE_VIS_ONLY iterator_traits<_Tp*>

{

    typedef ptrdiff_t difference_type;

    typedef typename remove_const<_Tp>::type value_type;

    typedef _Tp* pointer;

    typedef _Tp& reference;

    typedef random_access_iterator_tag iterator_category;

};

template <class _Tp, class _Up, bool = __has_iterator_category<iterator_traits<_Tp> >::value>

struct __has_iterator_category_convertible_to

    : public integral_constant<bool, is_convertible<typename iterator_traits<_Tp>::iterator_category, _Up>::value>

{};

template <class _Tp, class _Up>

struct __has_iterator_category_convertible_to<_Tp, _Up, false> : public false_type {};

template <class _Tp>

struct __is_input_iterator : public __has_iterator_category_convertible_to<_Tp, input_iterator_tag> {};

template <class _Tp>

struct __is_forward_iterator : public __has_iterator_category_convertible_to<_Tp, forward_iterator_tag> {};

template <class _Tp>

struct __is_bidirectional_iterator : public __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag> {};

template <class _Tp>

struct __is_random_access_iterator : public __has_iterator_category_convertible_to<_Tp, random_access_iterator_tag> {};

template<class _Category, class _Tp, class _Distance = ptrdiff_t,

         class _Pointer = _Tp*, class _Reference = _Tp&>

struct _LIBCPP_TYPE_VIS_ONLY iterator

{

    typedef _Tp        value_type;

    typedef _Distance  difference_type;

    typedef _Pointer   pointer;

    typedef _Reference reference;

    typedef _Category  iterator_category;

};

template <class _InputIter>

inline _LIBCPP_INLINE_VISIBILITY

void __advance(_InputIter& __i,

             typename iterator_traits<_InputIter>::difference_type __n, input_iterator_tag)

{

    for (; __n > 0; --__n)

        ++__i;

}

template <class _BiDirIter>

inline _LIBCPP_INLINE_VISIBILITY

void __advance(_BiDirIter& __i,

             typename iterator_traits<_BiDirIter>::difference_type __n, bidirectional_iterator_tag)

{

    if (__n >= 0)

        for (; __n > 0; --__n)

            ++__i;

    else

        for (; __n < 0; ++__n)

            --__i;

}

template <class _RandIter>

inline _LIBCPP_INLINE_VISIBILITY

void __advance(_RandIter& __i,

             typename iterator_traits<_RandIter>::difference_type __n, random_access_iterator_tag)

{

   __i += __n;

}

template <class _InputIter>

inline _LIBCPP_INLINE_VISIBILITY

void advance(_InputIter& __i,

             typename iterator_traits<_InputIter>::difference_type __n)

{

    __advance(__i, __n, typename iterator_traits<_InputIter>::iterator_category());

}

template <class _InputIter>

inline _LIBCPP_INLINE_VISIBILITY

typename iterator_traits<_InputIter>::difference_type

__distance(_InputIter __first, _InputIter __last, input_iterator_tag)

{

    typename iterator_traits<_InputIter>::difference_type __r(0);

    for (; __first != __last; ++__first)

        ++__r;

    return __r;

}

template <class _RandIter>

inline _LIBCPP_INLINE_VISIBILITY

typename iterator_traits<_RandIter>::difference_type

__distance(_RandIter __first, _RandIter __last, random_access_iterator_tag)

{

    return __last - __first;

}

template <class _InputIter>

inline _LIBCPP_INLINE_VISIBILITY

typename iterator_traits<_InputIter>::difference_type

distance(_InputIter __first, _InputIter __last)

{

    return __distance(__first, __last, typename iterator_traits<_InputIter>::iterator_category());

}

template <class _ForwardIter>

inline _LIBCPP_INLINE_VISIBILITY

_ForwardIter

next(_ForwardIter __x,

     typename iterator_traits<_ForwardIter>::difference_type __n = 1,

     typename enable_if<__is_forward_iterator<_ForwardIter>::value>::type* = 0)

{

    _VSTD::advance(__x, __n);

    return __x;

}

template <class _BidiretionalIter>

inline _LIBCPP_INLINE_VISIBILITY

_BidiretionalIter

prev(_BidiretionalIter __x,

     typename iterator_traits<_BidiretionalIter>::difference_type __n = 1,

     typename enable_if<__is_bidirectional_iterator<_BidiretionalIter>::value>::type* = 0)

{

    _VSTD::advance(__x, -__n);

    return __x;

}

template <class _Iter>

class _LIBCPP_TYPE_VIS_ONLY reverse_iterator

    : public iterator<typename iterator_traits<_Iter>::iterator_category,

                      typename iterator_traits<_Iter>::value_type,

                      typename iterator_traits<_Iter>::difference_type,

                      typename iterator_traits<_Iter>::pointer,

                      typename iterator_traits<_Iter>::reference>

{

private:

    mutable _Iter __t;  // no longer used as of LWG #2360, not removed due to ABI break

protected:

    _Iter current;

public:

    typedef _Iter                                            iterator_type;

    typedef typename iterator_traits<_Iter>::difference_type difference_type;

    typedef typename iterator_traits<_Iter>::reference       reference;

    typedef typename iterator_traits<_Iter>::pointer         pointer;

    _LIBCPP_INLINE_VISIBILITY reverse_iterator() : current() {}

    _LIBCPP_INLINE_VISIBILITY explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}

    template <class _Up> _LIBCPP_INLINE_VISIBILITY reverse_iterator(const reverse_iterator<_Up>& __u)

        : __t(__u.base()), current(__u.base()) {}

    _LIBCPP_INLINE_VISIBILITY _Iter base() const {return current;}

    _LIBCPP_INLINE_VISIBILITY reference operator*() const {_Iter __tmp = current; return *--__tmp;}

    _LIBCPP_INLINE_VISIBILITY pointer  operator->() const {return _VSTD::addressof(operator*());}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator& operator++() {--current; return *this;}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator  operator++(int)

        {reverse_iterator __tmp(*this); --current; return __tmp;}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator& operator--() {++current; return *this;}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator  operator--(int)

        {reverse_iterator __tmp(*this); ++current; return __tmp;}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator  operator+ (difference_type __n) const

        {return reverse_iterator(current - __n);}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator& operator+=(difference_type __n)

        {current -= __n; return *this;}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator  operator- (difference_type __n) const

        {return reverse_iterator(current + __n);}

    _LIBCPP_INLINE_VISIBILITY reverse_iterator& operator-=(difference_type __n)

        {current += __n; return *this;}

    _LIBCPP_INLINE_VISIBILITY reference         operator[](difference_type __n) const

        {return *(*this + __n);}

};

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator==(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)

{

    return __x.base() == __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator<(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)

{

    return __x.base() > __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator!=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)

{

    return __x.base() != __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)

{

    return __x.base() < __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator>=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)

{

    return __x.base() <= __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator<=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)

{

    return __x.base() >= __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

typename reverse_iterator<_Iter1>::difference_type

operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)

{

    return __y.base() - __x.base();

}

template <class _Iter>

inline _LIBCPP_INLINE_VISIBILITY

reverse_iterator<_Iter>

operator+(typename reverse_iterator<_Iter>::difference_type __n, const reverse_iterator<_Iter>& __x)

{

    return reverse_iterator<_Iter>(__x.base() - __n);

}

#if _LIBCPP_STD_VER > 11

template <class _Iter>

inline _LIBCPP_INLINE_VISIBILITY

reverse_iterator<_Iter> make_reverse_iterator(_Iter __i)

{

    return reverse_iterator<_Iter>(__i);

}

#endif

template <class _Container>

class _LIBCPP_TYPE_VIS_ONLY back_insert_iterator

    : public iterator<output_iterator_tag,

                      void,

                      void,

                      void,

                      back_insert_iterator<_Container>&>

{

protected:

    _Container* container;

public:

    typedef _Container container_type;

    _LIBCPP_INLINE_VISIBILITY explicit back_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}

    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator=(const typename _Container::value_type& __value_)

        {container->push_back(__value_); return *this;}

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator=(typename _Container::value_type&& __value_)

        {container->push_back(_VSTD::move(__value_)); return *this;}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator*()     {return *this;}

    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator++()    {return *this;}

    _LIBCPP_INLINE_VISIBILITY back_insert_iterator  operator++(int) {return *this;}

};

template <class _Container>

inline _LIBCPP_INLINE_VISIBILITY

back_insert_iterator<_Container>

back_inserter(_Container& __x)

{

    return back_insert_iterator<_Container>(__x);

}

template <class _Container>

class _LIBCPP_TYPE_VIS_ONLY front_insert_iterator

    : public iterator<output_iterator_tag,

                      void,

                      void,

                      void,

                      front_insert_iterator<_Container>&>

{

protected:

    _Container* container;

public:

    typedef _Container container_type;

    _LIBCPP_INLINE_VISIBILITY explicit front_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}

    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator=(const typename _Container::value_type& __value_)

        {container->push_front(__value_); return *this;}

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator=(typename _Container::value_type&& __value_)

        {container->push_front(_VSTD::move(__value_)); return *this;}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator*()     {return *this;}

    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator++()    {return *this;}

    _LIBCPP_INLINE_VISIBILITY front_insert_iterator  operator++(int) {return *this;}

};

template <class _Container>

inline _LIBCPP_INLINE_VISIBILITY

front_insert_iterator<_Container>

front_inserter(_Container& __x)

{

    return front_insert_iterator<_Container>(__x);

}

template <class _Container>

class _LIBCPP_TYPE_VIS_ONLY insert_iterator

    : public iterator<output_iterator_tag,

                      void,

                      void,

                      void,

                      insert_iterator<_Container>&>

{

protected:

    _Container* container;

    typename _Container::iterator iter;

public:

    typedef _Container container_type;

    _LIBCPP_INLINE_VISIBILITY insert_iterator(_Container& __x, typename _Container::iterator __i)

        : container(_VSTD::addressof(__x)), iter(__i) {}

    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator=(const typename _Container::value_type& __value_)

        {iter = container->insert(iter, __value_); ++iter; return *this;}

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator=(typename _Container::value_type&& __value_)

        {iter = container->insert(iter, _VSTD::move(__value_)); ++iter; return *this;}

#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES

    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator*()        {return *this;}

    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator++()       {return *this;}

    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator++(int)    {return *this;}

};

template <class _Container>

inline _LIBCPP_INLINE_VISIBILITY

insert_iterator<_Container>

inserter(_Container& __x, typename _Container::iterator __i)

{

    return insert_iterator<_Container>(__x, __i);

}

template <class _Tp, class _CharT = char,

          class _Traits = char_traits<_CharT>, class _Distance = ptrdiff_t>

class _LIBCPP_TYPE_VIS_ONLY istream_iterator

    : public iterator<input_iterator_tag, _Tp, _Distance, const _Tp*, const _Tp&>

{

public:

    typedef _CharT char_type;

    typedef _Traits traits_type;

    typedef basic_istream<_CharT,_Traits> istream_type;

private:

    istream_type* __in_stream_;

    _Tp __value_;

public:

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istream_iterator() : __in_stream_(0), __value_() {}

    _LIBCPP_INLINE_VISIBILITY istream_iterator(istream_type& __s) : __in_stream_(&__s)

        {

            if (!(*__in_stream_ >> __value_))

                __in_stream_ = 0;

        }

    _LIBCPP_INLINE_VISIBILITY const _Tp& operator*() const {return __value_;}

    _LIBCPP_INLINE_VISIBILITY const _Tp* operator->() const {return &(operator*());}

    _LIBCPP_INLINE_VISIBILITY istream_iterator& operator++()

        {

            if (!(*__in_stream_ >> __value_))

                __in_stream_ = 0;

            return *this;

        }

    _LIBCPP_INLINE_VISIBILITY istream_iterator  operator++(int)

        {istream_iterator __t(*this); ++(*this); return __t;}

    friend _LIBCPP_INLINE_VISIBILITY

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

        {return __x.__in_stream_ == __y.__in_stream_;}

    friend _LIBCPP_INLINE_VISIBILITY

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

        {return !(__x == __y);}

};

template <class _Tp, class _CharT = char, class _Traits = char_traits<_CharT> >

class _LIBCPP_TYPE_VIS_ONLY ostream_iterator

    : public iterator<output_iterator_tag, void, void, void, void>

{

public:

    typedef _CharT char_type;

    typedef _Traits traits_type;

    typedef basic_ostream<_CharT,_Traits> ostream_type;

private:

    ostream_type* __out_stream_;

    const char_type* __delim_;

public:

    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s)

        : __out_stream_(&__s), __delim_(0) {}

    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s, const _CharT* __delimiter)

        : __out_stream_(&__s), __delim_(__delimiter) {}

    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator=(const _Tp& __value_)

        {

            *__out_stream_ << __value_;

            if (__delim_)

                *__out_stream_ << __delim_;

            return *this;

        }

    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator*()     {return *this;}

    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++()    {return *this;}

    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++(int) {return *this;}

};

template<class _CharT, class _Traits>

class _LIBCPP_TYPE_VIS_ONLY istreambuf_iterator

    : public iterator<input_iterator_tag, _CharT,

                      typename _Traits::off_type, _CharT*,

                      _CharT>

{

public:

    typedef _CharT                          char_type;

    typedef _Traits                         traits_type;

    typedef typename _Traits::int_type      int_type;

    typedef basic_streambuf<_CharT,_Traits> streambuf_type;

    typedef basic_istream<_CharT,_Traits>   istream_type;

private:

    mutable streambuf_type* __sbuf_;

    class __proxy

    {

        char_type __keep_;

        streambuf_type* __sbuf_;

        _LIBCPP_INLINE_VISIBILITY __proxy(char_type __c, streambuf_type* __s)

            : __keep_(__c), __sbuf_(__s) {}

        friend class istreambuf_iterator;

    public:

        _LIBCPP_INLINE_VISIBILITY char_type operator*() const {return __keep_;}

    };

    _LIBCPP_INLINE_VISIBILITY

    bool __test_for_eof() const

    {

        if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sgetc(), traits_type::eof()))

            __sbuf_ = 0;

        return __sbuf_ == 0;

    }

public:

    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istreambuf_iterator() _NOEXCEPT : __sbuf_(0) {}

    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(istream_type& __s) _NOEXCEPT

        : __sbuf_(__s.rdbuf()) {}

    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(streambuf_type* __s) _NOEXCEPT

        : __sbuf_(__s) {}

    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(const __proxy& __p) _NOEXCEPT

        : __sbuf_(__p.__sbuf_) {}

    _LIBCPP_INLINE_VISIBILITY char_type  operator*() const

        {return static_cast<char_type>(__sbuf_->sgetc());}

    _LIBCPP_INLINE_VISIBILITY char_type* operator->() const {return nullptr;}

    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator& operator++()

        {

            __sbuf_->sbumpc();

            return *this;

        }

    _LIBCPP_INLINE_VISIBILITY __proxy              operator++(int)

        {

            return __proxy(__sbuf_->sbumpc(), __sbuf_);

        }

    _LIBCPP_INLINE_VISIBILITY bool equal(const istreambuf_iterator& __b) const

        {return __test_for_eof() == __b.__test_for_eof();}

};

template <class _CharT, class _Traits>

inline _LIBCPP_INLINE_VISIBILITY

bool operator==(const istreambuf_iterator<_CharT,_Traits>& __a,

                const istreambuf_iterator<_CharT,_Traits>& __b)

                {return __a.equal(__b);}

template <class _CharT, class _Traits>

inline _LIBCPP_INLINE_VISIBILITY

bool operator!=(const istreambuf_iterator<_CharT,_Traits>& __a,

                const istreambuf_iterator<_CharT,_Traits>& __b)

                {return !__a.equal(__b);}

template <class _CharT, class _Traits>

class _LIBCPP_TYPE_VIS_ONLY ostreambuf_iterator

    : public iterator<output_iterator_tag, void, void, void, void>

{

public:

    typedef _CharT                          char_type;

    typedef _Traits                         traits_type;

    typedef basic_streambuf<_CharT,_Traits> streambuf_type;

    typedef basic_ostream<_CharT,_Traits>   ostream_type;

private:

    streambuf_type* __sbuf_;

public:

    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(ostream_type& __s) _NOEXCEPT

        : __sbuf_(__s.rdbuf()) {}

    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(streambuf_type* __s) _NOEXCEPT

        : __sbuf_(__s) {}

    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator=(_CharT __c)

        {

            if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sputc(__c), traits_type::eof()))

                __sbuf_ = 0;

            return *this;

        }

    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator*()     {return *this;}

    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++()    {return *this;}

    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++(int) {return *this;}

    _LIBCPP_INLINE_VISIBILITY bool failed() const _NOEXCEPT {return __sbuf_ == 0;}

#if !defined(__APPLE__) || \

    (defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && __MAC_OS_X_VERSION_MIN_REQUIRED > __MAC_10_8) || \

    (defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && __IPHONE_OS_VERSION_MIN_REQUIRED > __IPHONE_6_0)

    template <class _Ch, class _Tr>

    friend

    _LIBCPP_HIDDEN

    ostreambuf_iterator<_Ch, _Tr>

    __pad_and_output(ostreambuf_iterator<_Ch, _Tr> __s,

                     const _Ch* __ob, const _Ch* __op, const _Ch* __oe,

                     ios_base& __iob, _Ch __fl);

#endif

};

template <class _Iter>

class _LIBCPP_TYPE_VIS_ONLY move_iterator

{

private:

    _Iter __i;

public:

    typedef _Iter                                            iterator_type;

    typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;

    typedef typename iterator_traits<iterator_type>::value_type value_type;

    typedef typename iterator_traits<iterator_type>::difference_type difference_type;

    typedef typename iterator_traits<iterator_type>::pointer pointer;

#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

    typedef value_type&& reference;

#else

    typedef typename iterator_traits<iterator_type>::reference reference;

#endif

    _LIBCPP_INLINE_VISIBILITY move_iterator() : __i() {}

    _LIBCPP_INLINE_VISIBILITY explicit move_iterator(_Iter __x) : __i(__x) {}

    template <class _Up> _LIBCPP_INLINE_VISIBILITY move_iterator(const move_iterator<_Up>& __u)

        : __i(__u.base()) {}

    _LIBCPP_INLINE_VISIBILITY _Iter base() const {return __i;}

    _LIBCPP_INLINE_VISIBILITY reference operator*() const {

      return static_cast<reference>(*__i);

    }

    _LIBCPP_INLINE_VISIBILITY pointer  operator->() const {

      typename iterator_traits<iterator_type>::reference __ref = *__i;

      return &__ref;

    }

    _LIBCPP_INLINE_VISIBILITY move_iterator& operator++() {++__i; return *this;}

    _LIBCPP_INLINE_VISIBILITY move_iterator  operator++(int)

        {move_iterator __tmp(*this); ++__i; return __tmp;}

    _LIBCPP_INLINE_VISIBILITY move_iterator& operator--() {--__i; return *this;}

    _LIBCPP_INLINE_VISIBILITY move_iterator  operator--(int)

        {move_iterator __tmp(*this); --__i; return __tmp;}

    _LIBCPP_INLINE_VISIBILITY move_iterator  operator+ (difference_type __n) const

        {return move_iterator(__i + __n);}

    _LIBCPP_INLINE_VISIBILITY move_iterator& operator+=(difference_type __n)

        {__i += __n; return *this;}

    _LIBCPP_INLINE_VISIBILITY move_iterator  operator- (difference_type __n) const

        {return move_iterator(__i - __n);}

    _LIBCPP_INLINE_VISIBILITY move_iterator& operator-=(difference_type __n)

        {__i -= __n; return *this;}

    _LIBCPP_INLINE_VISIBILITY reference         operator[](difference_type __n) const

    {

      return static_cast<reference>(__i[__n]);

    }

};

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)

{

    return __x.base() == __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)

{

    return __x.base() < __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)

{

    return __x.base() != __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)

{

    return __x.base() > __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)

{

    return __x.base() >= __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

bool

operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)

{

    return __x.base() <= __y.base();

}

template <class _Iter1, class _Iter2>

inline _LIBCPP_INLINE_VISIBILITY

typename move_iterator<_Iter1>::difference_type

operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)

{

    return __x.base() - __y.base();

}

template <class _Iter>

inline _LIBCPP_INLINE_VISIBILITY

move_iterator<_Iter>

operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x)

{

    return move_iterator<_Iter>(__x.base() + __n);

}

template <class _Iter>

inline _LIBCPP_INLINE_VISIBILITY

move_iterator<_Iter>

make_move_iterator(_Iter __i)

{

    return move_iterator<_Iter>(__i);

}

// __wrap_iter

template <class _Iter> class __wrap_iter;

template <class _Iter1, class _Iter2>

_LIBCPP_INLINE_VISIBILITY

bool

operator==(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;

template <class _Iter1, class _Iter2>

_LIBCPP_INLINE_VISIBILITY

bool

operator<(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;

template <class _Iter1, class _Iter2>

_LIBCPP_INLINE_VISIBILITY

bool

operator!=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;

template <class _Iter1, class _Iter2>

_LIBCPP_INLINE_VISIBILITY

bool

operator>(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;

template <class _Iter1, class _Iter2>

_LIBCPP_INLINE_VISIBILITY

bool

operator>=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;

template <class _Iter1, class _Iter2>

_LIBCPP_INLINE_VISIBILITY

bool

operator<=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;

template <class _Iter1, class _Iter2>

_LIBCPP_INLINE_VISIBILITY

typename __wrap_iter<_Iter1>::difference_type

operator-(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;

template <class _Iter>

_LIBCPP_INLINE_VISIBILITY

__wrap_iter<_Iter>

operator+(typename __wrap_iter<_Iter>::difference_type, __wrap_iter<_Iter>) _NOEXCEPT;

template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY copy(_Ip, _Ip, _Op);

template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY copy_backward(_B1, _B1, _B2);

template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY move(_Ip, _Ip, _Op);

template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY move_backward(_B1, _B1, _B2);

template <class _Tp>

_LIBCPP_INLINE_VISIBILITY

typename enable_if

<

    is_trivially_copy_assignable<_Tp>::value,

    _Tp*

>::type

__unwrap_iter(__wrap_iter<_Tp*>);

template <class _Iter>

class __wrap_iter

{

public:

    typedef _Iter                                                      iterator_type;

    typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;

    typedef typename iterator_traits<iterator_type>::value_type        value_type;

    typedef typename iterator_traits<iterator_type>::difference_type   difference_type;

    typedef typename iterator_traits<iterator_type>::pointer           pointer;

    typedef typename iterator_traits<iterator_type>::reference         reference;

private:

    iterator_type __i;

public:

    _LIBCPP_INLINE_VISIBILITY __wrap_iter() _NOEXCEPT

#if _LIBCPP_STD_VER > 11

                : __i{}

#endif