// -*- 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___RANGES_ELEMENTS_VIEW_H
#define _LIBCPP___RANGES_ELEMENTS_VIEW_H
#include <__compare/three_way_comparable.h>
#include <__concepts/constructible.h>
#include <__concepts/convertible_to.h>
#include <__concepts/derived_from.h>
#include <__concepts/equality_comparable.h>
#include <__config>
#include <__fwd/complex.h>
#include <__iterator/concepts.h>
#include <__iterator/iterator_traits.h>
#include <__ranges/access.h>
#include <__ranges/all.h>
#include <__ranges/concepts.h>
#include <__ranges/enable_borrowed_range.h>
#include <__ranges/range_adaptor.h>
#include <__ranges/size.h>
#include <__ranges/view_interface.h>
#include <__tuple/tuple_element.h>
#include <__tuple/tuple_like.h>
#include <__tuple/tuple_size.h>
#include <__type_traits/is_reference.h>
#include <__type_traits/maybe_const.h>
#include <__type_traits/remove_cv.h>
#include <__type_traits/remove_cvref.h>
#include <__type_traits/remove_reference.h>
#include <__utility/declval.h>
#include <__utility/forward.h>
#include <__utility/move.h>
#include <cstddef>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
namespace ranges {
template <class _Tp, size_t _Np>
concept __has_tuple_element = __tuple_like<_Tp> && _Np < tuple_size<_Tp>::value;
template <class _Tp, size_t _Np>
concept __returnable_element = is_reference_v<_Tp> || move_constructible<tuple_element_t<_Np, _Tp>>;
template <input_range _View, size_t _Np>
requires view<_View> && __has_tuple_element<range_value_t<_View>, _Np> &&
__has_tuple_element<remove_reference_t<range_reference_t<_View>>, _Np> &&
__returnable_element<range_reference_t<_View>, _Np>
class elements_view : public view_interface<elements_view<_View, _Np>> {
private:
template <bool>
class __iterator;
template <bool>
class __sentinel;
public:
_LIBCPP_HIDE_FROM_ABI elements_view()
requires default_initializable<_View>
= default;
_LIBCPP_HIDE_FROM_ABI constexpr explicit elements_view(_View __base) : __base_(std::move(__base)) {}
_LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
requires copy_constructible<_View>
{
return __base_;
}
_LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }
_LIBCPP_HIDE_FROM_ABI constexpr auto begin()
requires(!__simple_view<_View>)
{
return __iterator</*_Const=*/false>(ranges::begin(__base_));
}
_LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
requires range<const _View>
{
return __iterator</*_Const=*/true>(ranges::begin(__base_));
}
_LIBCPP_HIDE_FROM_ABI constexpr auto end()
requires(!__simple_view<_View> && !common_range<_View>)
{
return __sentinel</*_Const=*/false>{ranges::end(__base_)};
}
_LIBCPP_HIDE_FROM_ABI constexpr auto end()
requires(!__simple_view<_View> && common_range<_View>)
{
return __iterator</*_Const=*/false>{ranges::end(__base_)};
}
_LIBCPP_HIDE_FROM_ABI constexpr auto end() const
requires range<const _View>
{
return __sentinel</*_Const=*/true>{ranges::end(__base_)};
}
_LIBCPP_HIDE_FROM_ABI constexpr auto end() const
requires common_range<const _View>
{
return __iterator</*_Const=*/true>{ranges::end(__base_)};
}
_LIBCPP_HIDE_FROM_ABI constexpr auto size()
requires sized_range<_View>
{
return ranges::size(__base_);
}
_LIBCPP_HIDE_FROM_ABI constexpr auto size() const
requires sized_range<const _View>
{
return ranges::size(__base_);
}
private:
_LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
};
template <class, size_t>
struct __elements_view_iterator_category_base {};
template <forward_range _Base, size_t _Np>
struct __elements_view_iterator_category_base<_Base, _Np> {
static consteval auto __get_iterator_category() {
using _Result = decltype(std::get<_Np>(*std::declval<iterator_t<_Base>>()));
using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
if constexpr (!is_lvalue_reference_v<_Result>) {
return input_iterator_tag{};
} else if constexpr (derived_from<_Cat, random_access_iterator_tag>) {
return random_access_iterator_tag{};
} else {
return _Cat{};
}
}
using iterator_category = decltype(__get_iterator_category());
};
template <input_range _View, size_t _Np>
requires view<_View> && __has_tuple_element<range_value_t<_View>, _Np> &&
__has_tuple_element<remove_reference_t<range_reference_t<_View>>, _Np> &&
__returnable_element<range_reference_t<_View>, _Np>
template <bool _Const>
class elements_view<_View, _Np>::__iterator
: public __elements_view_iterator_category_base<__maybe_const<_Const, _View>, _Np> {
template <bool>
friend class __iterator;
template <bool>
friend class __sentinel;
using _Base = __maybe_const<_Const, _View>;
iterator_t<_Base> __current_ = iterator_t<_Base>();
_LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __get_element(const iterator_t<_Base>& __i) {
if constexpr (is_reference_v<range_reference_t<_Base>>) {
return std::get<_Np>(*__i);
} else {
using _Element = remove_cv_t<tuple_element_t<_Np, range_reference_t<_Base>>>;
return static_cast<_Element>(std::get<_Np>(*__i));
}
}
static consteval auto __get_iterator_concept() {
if constexpr (random_access_range<_Base>) {
return random_access_iterator_tag{};
} else if constexpr (bidirectional_range<_Base>) {
return bidirectional_iterator_tag{};
} else if constexpr (forward_range<_Base>) {
return forward_iterator_tag{};
} else {
return input_iterator_tag{};
}
}
public:
using iterator_concept = decltype(__get_iterator_concept());
using value_type = remove_cvref_t<tuple_element_t<_Np, range_value_t<_Base>>>;
using difference_type = range_difference_t<_Base>;
_LIBCPP_HIDE_FROM_ABI __iterator()
requires default_initializable<iterator_t<_Base>>
= default;
_LIBCPP_HIDE_FROM_ABI constexpr explicit __iterator(iterator_t<_Base> __current) : __current_(std::move(__current)) {}
_LIBCPP_HIDE_FROM_ABI constexpr __iterator(__iterator<!_Const> __i)
requires _Const && convertible_to<iterator_t<_View>, iterator_t<_Base>>
: __current_(std::move(__i.__current_)) {}
_LIBCPP_HIDE_FROM_ABI constexpr const iterator_t<_Base>& base() const& noexcept { return __current_; }
_LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_Base> base() && { return std::move(__current_); }
_LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator*() const { return __get_element(__current_); }
_LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() {
++__current_;
return *this;
}
_LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++__current_; }
_LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int)
requires forward_range<_Base>
{
auto __temp = *this;
++__current_;
return __temp;
}
_LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--()
requires bidirectional_range<_Base>
{
--__current_;
return *this;
}
_LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int)
requires bidirectional_range<_Base>
{
auto __temp = *this;
--__current_;
return __temp;
}
_LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator+=(difference_type __n)
requires random_access_range<_Base>
{
__current_ += __n;
return *this;
}
_LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator-=(difference_type __n)
requires random_access_range<_Base>
{
__current_ -= __n;
return *this;
}
_LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator[](difference_type __n) const
requires random_access_range<_Base>
{
return __get_element(__current_ + __n);
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
requires equality_comparable<iterator_t<_Base>>
{
return __x.__current_ == __y.__current_;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(const __iterator& __x, const __iterator& __y)
requires random_access_range<_Base>
{
return __x.__current_ < __y.__current_;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(const __iterator& __x, const __iterator& __y)
requires random_access_range<_Base>
{
return __y < __x;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y)
requires random_access_range<_Base>
{
return !(__y < __x);
}
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y)
requires random_access_range<_Base>
{
return !(__x < __y);
}
_LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
requires random_access_range<_Base> && three_way_comparable<iterator_t<_Base>>
{
return __x.__current_ <=> __y.__current_;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(const __iterator& __x, difference_type __y)
requires random_access_range<_Base>
{
return __iterator{__x} += __y;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(difference_type __x, const __iterator& __y)
requires random_access_range<_Base>
{
return __y + __x;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator-(const __iterator& __x, difference_type __y)
requires random_access_range<_Base>
{
return __iterator{__x} -= __y;
}
_LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)
requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
{
return __x.__current_ - __y.__current_;
}
};
template <input_range _View, size_t _Np>
requires view<_View> && __has_tuple_element<range_value_t<_View>, _Np> &&
__has_tuple_element<remove_reference_t<range_reference_t<_View>>, _Np> &&
__returnable_element<range_reference_t<_View>, _Np>
template <bool _Const>
class elements_view<_View, _Np>::__sentinel {
private:
using _Base = __maybe_const<_Const, _View>;
_LIBCPP_NO_UNIQUE_ADDRESS sentinel_t<_Base> __end_ = sentinel_t<_Base>();
template <bool>
friend class __sentinel;
template <bool _AnyConst>
_LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __get_current(const __iterator<_AnyConst>& __iter) {
return (__iter.__current_);
}
public:
_LIBCPP_HIDE_FROM_ABI __sentinel() = default;
_LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(sentinel_t<_Base> __end) : __end_(std::move(__end)) {}
_LIBCPP_HIDE_FROM_ABI constexpr __sentinel(__sentinel<!_Const> __other)
requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
: __end_(std::move(__other.__end_)) {}
_LIBCPP_HIDE_FROM_ABI constexpr sentinel_t<_Base> base() const { return __end_; }
template <bool _OtherConst>
requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
_LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
return __get_current(__x) == __y.__end_;
}
template <bool _OtherConst>
requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
_LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
return __get_current(__x) - __y.__end_;
}
template <bool _OtherConst>
requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
_LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
operator-(const __sentinel& __x, const __iterator<_OtherConst>& __y) {
return __x.__end_ - __get_current(__y);
}
};
template <class _Tp, size_t _Np>
inline constexpr bool enable_borrowed_range<elements_view<_Tp, _Np>> = enable_borrowed_range<_Tp>;
template <class _Tp>
using keys_view = elements_view<_Tp, 0>;
template <class _Tp>
using values_view = elements_view<_Tp, 1>;
namespace views {
namespace __elements {
template <size_t _Np>
struct __fn : __range_adaptor_closure<__fn<_Np>> {
template <class _Range>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range) const
/**/ noexcept(noexcept(elements_view<all_t<_Range&&>, _Np>(std::forward<_Range>(__range))))
/*------*/ -> decltype(elements_view<all_t<_Range&&>, _Np>(std::forward<_Range>(__range))) {
/*-------------*/ return elements_view<all_t<_Range&&>, _Np>(std::forward<_Range>(__range));
}
};
} // namespace __elements
inline namespace __cpo {
template <size_t _Np>
inline constexpr auto elements = __elements::__fn<_Np>{};
inline constexpr auto keys = elements<0>;
inline constexpr auto values = elements<1>;
} // namespace __cpo
} // namespace views
} // namespace ranges
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANGES_ELEMENTS_VIEW_H
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