// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___ITERATOR_MOVE_ITERATOR_H
#define _LIBCPP___ITERATOR_MOVE_ITERATOR_H

#include <__compare/compare_three_way_result.h>
#include <__compare/three_way_comparable.h>
#include <__concepts/assignable.h>
#include <__concepts/convertible_to.h>
#include <__concepts/derived_from.h>
#include <__concepts/same_as.h>
#include <__config>
#include <__iterator/concepts.h>
#include <__iterator/incrementable_traits.h>
#include <__iterator/iter_move.h>
#include <__iterator/iter_swap.h>
#include <__iterator/iterator_traits.h>
#include <__iterator/move_sentinel.h>
#include <__iterator/readable_traits.h>
#include <__utility/move.h>
#include <type_traits>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER > 17
template<class _Iter, class = void>
struct __move_iter_category_base {};

template<class _Iter>
  requires requires { typename iterator_traits<_Iter>::iterator_category; }
struct __move_iter_category_base<_Iter> {
    using iterator_category = _If<
        derived_from<typename iterator_traits<_Iter>::iterator_category, random_access_iterator_tag>,
        random_access_iterator_tag,
        typename iterator_traits<_Iter>::iterator_category
    >;
};

template<class _Iter, class _Sent>
concept __move_iter_comparable = requires {
    { declval<const _Iter&>() == declval<_Sent>() } -> convertible_to<bool>;
};
#endif // _LIBCPP_STD_VER > 17

template <class _Iter>
class _LIBCPP_TEMPLATE_VIS move_iterator
#if _LIBCPP_STD_VER > 17
    : public __move_iter_category_base<_Iter>
#endif
{
public:
#if _LIBCPP_STD_VER > 17
    using iterator_type = _Iter;
    using iterator_concept = input_iterator_tag;
    // iterator_category is inherited and not always present
    using value_type = iter_value_t<_Iter>;
    using difference_type = iter_difference_t<_Iter>;
    using pointer = _Iter;
    using reference = iter_rvalue_reference_t<_Iter>;
#else
    typedef _Iter iterator_type;
    typedef _If<
        __is_cpp17_random_access_iterator<_Iter>::value,
        random_access_iterator_tag,
        typename iterator_traits<_Iter>::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 iterator_type pointer;

    typedef typename iterator_traits<iterator_type>::reference __reference;
    typedef typename conditional<
            is_reference<__reference>::value,
            typename remove_reference<__reference>::type&&,
            __reference
        >::type reference;
#endif // _LIBCPP_STD_VER > 17

    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    explicit move_iterator(_Iter __i) : __current_(std::move(__i)) {}

    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator& operator++() { ++__current_; return *this; }

#if _LIBCPP_STD_VER > 17
    _LIBCPP_HIDE_FROM_ABI constexpr
    move_iterator() requires is_constructible_v<_Iter> : __current_() {}

    template <class _Up>
        requires (!_IsSame<_Up, _Iter>::value) && convertible_to<const _Up&, _Iter>
    _LIBCPP_HIDE_FROM_ABI constexpr
    move_iterator(const move_iterator<_Up>& __u) : __current_(__u.base()) {}

    template <class _Up>
        requires (!_IsSame<_Up, _Iter>::value) &&
                 convertible_to<const _Up&, _Iter> &&
                 assignable_from<_Iter&, const _Up&>
    _LIBCPP_HIDE_FROM_ABI constexpr
    move_iterator& operator=(const move_iterator<_Up>& __u) {
        __current_ = __u.base();
        return *this;
    }

    _LIBCPP_HIDE_FROM_ABI constexpr const _Iter& base() const & noexcept { return __current_; }
    _LIBCPP_HIDE_FROM_ABI constexpr _Iter base() && { return std::move(__current_); }

    _LIBCPP_HIDE_FROM_ABI constexpr
    reference operator*() const { return ranges::iter_move(__current_); }
    _LIBCPP_HIDE_FROM_ABI constexpr
    reference operator[](difference_type __n) const { return ranges::iter_move(__current_ + __n); }

    _LIBCPP_HIDE_FROM_ABI constexpr
    auto operator++(int)
        requires forward_iterator<_Iter>
    {
        move_iterator __tmp(*this); ++__current_; return __tmp;
    }

    _LIBCPP_HIDE_FROM_ABI constexpr
    void operator++(int) { ++__current_; }
#else
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator() : __current_() {}

    template <class _Up, class = __enable_if_t<
        !is_same<_Up, _Iter>::value && is_convertible<const _Up&, _Iter>::value
    > >
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator(const move_iterator<_Up>& __u) : __current_(__u.base()) {}

    template <class _Up, class = __enable_if_t<
        !is_same<_Up, _Iter>::value &&
        is_convertible<const _Up&, _Iter>::value &&
        is_assignable<_Iter&, const _Up&>::value
    > >
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator& operator=(const move_iterator<_Up>& __u) {
        __current_ = __u.base();
        return *this;
    }

    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    _Iter base() const { return __current_; }

    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    reference operator*() const { return static_cast<reference>(*__current_); }
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    pointer operator->() const { return __current_; }
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    reference operator[](difference_type __n) const { return static_cast<reference>(__current_[__n]); }

    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator operator++(int) { move_iterator __tmp(*this); ++__current_; return __tmp; }
#endif // _LIBCPP_STD_VER > 17

    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator& operator--() { --__current_; return *this; }
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator operator--(int) { move_iterator __tmp(*this); --__current_; return __tmp; }
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator operator+(difference_type __n) const { return move_iterator(__current_ + __n); }
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator& operator+=(difference_type __n) { __current_ += __n; return *this; }
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator operator-(difference_type __n) const { return move_iterator(__current_ - __n); }
    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
    move_iterator& operator-=(difference_type __n) { __current_ -= __n; return *this; }

#if _LIBCPP_STD_VER > 17
    template<sentinel_for<_Iter> _Sent>
    friend _LIBCPP_HIDE_FROM_ABI constexpr
    bool operator==(const move_iterator& __x, const move_sentinel<_Sent>& __y)
        requires __move_iter_comparable<_Iter, _Sent>
    {
        return __x.base() == __y.base();
    }

    template<sized_sentinel_for<_Iter> _Sent>
    friend _LIBCPP_HIDE_FROM_ABI constexpr
    iter_difference_t<_Iter> operator-(const move_sentinel<_Sent>& __x, const move_iterator& __y)
    {
        return __x.base() - __y.base();
    }

    template<sized_sentinel_for<_Iter> _Sent>
    friend _LIBCPP_HIDE_FROM_ABI constexpr
    iter_difference_t<_Iter> operator-(const move_iterator& __x, const move_sentinel<_Sent>& __y)
    {
        return __x.base() - __y.base();
    }

    friend _LIBCPP_HIDE_FROM_ABI constexpr
    iter_rvalue_reference_t<_Iter> iter_move(const move_iterator& __i)
        noexcept(noexcept(ranges::iter_move(__i.__current_)))
    {
        return ranges::iter_move(__i.__current_);
    }

    template<indirectly_swappable<_Iter> _It2>
    friend _LIBCPP_HIDE_FROM_ABI constexpr
    void iter_swap(const move_iterator& __x, const move_iterator<_It2>& __y)
        noexcept(noexcept(ranges::iter_swap(__x.__current_, __y.__current_)))
    {
        return ranges::iter_swap(__x.__current_, __y.__current_);
    }
#endif // _LIBCPP_STD_VER > 17

private:
    template<class _It2> friend class move_iterator;

    _Iter __current_;
};

template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
bool operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
{
    return __x.base() == __y.base();
}

#if _LIBCPP_STD_VER <= 17
template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
bool operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
{
    return __x.base() != __y.base();
}
#endif // _LIBCPP_STD_VER <= 17

template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
bool operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
{
    return __x.base() < __y.base();
}

template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
bool operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
{
    return __x.base() > __y.base();
}

template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
bool operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
{
    return __x.base() <= __y.base();
}

template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
bool operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
{
    return __x.base() >= __y.base();
}

#if _LIBCPP_STD_VER > 17
template <class _Iter1, three_way_comparable_with<_Iter1> _Iter2>
inline _LIBCPP_HIDE_FROM_ABI constexpr
auto operator<=>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
    -> compare_three_way_result_t<_Iter1, _Iter2>
{
    return __x.base() <=> __y.base();
}
#endif // _LIBCPP_STD_VER > 17

#ifndef _LIBCPP_CXX03_LANG
template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
auto operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
    -> decltype(__x.base() - __y.base())
{
    return __x.base() - __y.base();
}
#else
template <class _Iter1, class _Iter2>
inline _LIBCPP_HIDE_FROM_ABI
typename move_iterator<_Iter1>::difference_type
operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
{
    return __x.base() - __y.base();
}
#endif // !_LIBCPP_CXX03_LANG

#if _LIBCPP_STD_VER > 17
template <class _Iter>
inline _LIBCPP_HIDE_FROM_ABI constexpr
move_iterator<_Iter> operator+(iter_difference_t<_Iter> __n, const move_iterator<_Iter>& __x)
    requires requires { { __x.base() + __n } -> same_as<_Iter>; }
{
    return __x + __n;
}
#else
template <class _Iter>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
move_iterator<_Iter>
operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x)
{
    return move_iterator<_Iter>(__x.base() + __n);
}
#endif // _LIBCPP_STD_VER > 17

template <class _Iter>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
move_iterator<_Iter>
make_move_iterator(_Iter __i)
{
    return move_iterator<_Iter>(std::move(__i));
}

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___ITERATOR_MOVE_ITERATOR_H