419 lines · c
1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___RANGES_ELEMENTS_VIEW_H11#define _LIBCPP___RANGES_ELEMENTS_VIEW_H12 13#include <__compare/three_way_comparable.h>14#include <__concepts/constructible.h>15#include <__concepts/convertible_to.h>16#include <__concepts/derived_from.h>17#include <__concepts/equality_comparable.h>18#include <__config>19#include <__fwd/get.h>20#include <__iterator/concepts.h>21#include <__iterator/iterator_traits.h>22#include <__ranges/access.h>23#include <__ranges/all.h>24#include <__ranges/concepts.h>25#include <__ranges/enable_borrowed_range.h>26#include <__ranges/range_adaptor.h>27#include <__ranges/size.h>28#include <__ranges/view_interface.h>29#include <__tuple/tuple_element.h>30#include <__tuple/tuple_like.h>31#include <__tuple/tuple_size.h>32#include <__type_traits/is_reference.h>33#include <__type_traits/maybe_const.h>34#include <__type_traits/remove_cv.h>35#include <__type_traits/remove_cvref.h>36#include <__type_traits/remove_reference.h>37#include <__utility/declval.h>38#include <__utility/forward.h>39#include <__utility/move.h>40#include <tuple> // std::get41 42#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)43# pragma GCC system_header44#endif45 46_LIBCPP_PUSH_MACROS47#include <__undef_macros>48 49_LIBCPP_BEGIN_NAMESPACE_STD50 51#if _LIBCPP_STD_VER >= 2052 53namespace ranges {54 55template <class _Tp, size_t _Np>56concept __has_tuple_element = __tuple_like<_Tp> && _Np < tuple_size<_Tp>::value;57 58template <class _Tp, size_t _Np>59concept __returnable_element = is_reference_v<_Tp> || move_constructible<tuple_element_t<_Np, _Tp>>;60 61template <input_range _View, size_t _Np>62 requires view<_View> && __has_tuple_element<range_value_t<_View>, _Np> &&63 __has_tuple_element<remove_reference_t<range_reference_t<_View>>, _Np> &&64 __returnable_element<range_reference_t<_View>, _Np>65class elements_view : public view_interface<elements_view<_View, _Np>> {66private:67 template <bool>68 class __iterator;69 70 template <bool>71 class __sentinel;72 73public:74 _LIBCPP_HIDE_FROM_ABI elements_view()75 requires default_initializable<_View>76 = default;77 78 _LIBCPP_HIDE_FROM_ABI constexpr explicit elements_view(_View __base) : __base_(std::move(__base)) {}79 80 _LIBCPP_HIDE_FROM_ABI constexpr _View base() const&81 requires copy_constructible<_View>82 {83 return __base_;84 }85 86 _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }87 88 _LIBCPP_HIDE_FROM_ABI constexpr auto begin()89 requires(!__simple_view<_View>)90 {91 return __iterator</*_Const=*/false>(ranges::begin(__base_));92 }93 94 _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const95 requires range<const _View>96 {97 return __iterator</*_Const=*/true>(ranges::begin(__base_));98 }99 100 _LIBCPP_HIDE_FROM_ABI constexpr auto end()101 requires(!__simple_view<_View> && !common_range<_View>)102 {103 return __sentinel</*_Const=*/false>{ranges::end(__base_)};104 }105 106 _LIBCPP_HIDE_FROM_ABI constexpr auto end()107 requires(!__simple_view<_View> && common_range<_View>)108 {109 return __iterator</*_Const=*/false>{ranges::end(__base_)};110 }111 112 _LIBCPP_HIDE_FROM_ABI constexpr auto end() const113 requires range<const _View>114 {115 return __sentinel</*_Const=*/true>{ranges::end(__base_)};116 }117 118 _LIBCPP_HIDE_FROM_ABI constexpr auto end() const119 requires common_range<const _View>120 {121 return __iterator</*_Const=*/true>{ranges::end(__base_)};122 }123 124 _LIBCPP_HIDE_FROM_ABI constexpr auto size()125 requires sized_range<_View>126 {127 return ranges::size(__base_);128 }129 130 _LIBCPP_HIDE_FROM_ABI constexpr auto size() const131 requires sized_range<const _View>132 {133 return ranges::size(__base_);134 }135 136private:137 _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();138};139 140template <class, size_t>141struct __elements_view_iterator_category_base {};142 143template <forward_range _Base, size_t _Np>144struct __elements_view_iterator_category_base<_Base, _Np> {145 static consteval auto __get_iterator_category() {146 using _Result = decltype(std::get<_Np>(*std::declval<iterator_t<_Base>>()));147 using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;148 149 if constexpr (!is_lvalue_reference_v<_Result>) {150 return input_iterator_tag{};151 } else if constexpr (derived_from<_Cat, random_access_iterator_tag>) {152 return random_access_iterator_tag{};153 } else {154 return _Cat{};155 }156 }157 158 using iterator_category = decltype(__get_iterator_category());159};160 161template <input_range _View, size_t _Np>162 requires view<_View> && __has_tuple_element<range_value_t<_View>, _Np> &&163 __has_tuple_element<remove_reference_t<range_reference_t<_View>>, _Np> &&164 __returnable_element<range_reference_t<_View>, _Np>165template <bool _Const>166class elements_view<_View, _Np>::__iterator167 : public __elements_view_iterator_category_base<__maybe_const<_Const, _View>, _Np> {168 template <bool>169 friend class __iterator;170 171 template <bool>172 friend class __sentinel;173 174 using _Base _LIBCPP_NODEBUG = __maybe_const<_Const, _View>;175 176 iterator_t<_Base> __current_ = iterator_t<_Base>();177 178 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __get_element(const iterator_t<_Base>& __i) {179 if constexpr (is_reference_v<range_reference_t<_Base>>) {180 return std::get<_Np>(*__i);181 } else {182 using _Element = remove_cv_t<tuple_element_t<_Np, range_reference_t<_Base>>>;183 return static_cast<_Element>(std::get<_Np>(*__i));184 }185 }186 187 static consteval auto __get_iterator_concept() {188 if constexpr (random_access_range<_Base>) {189 return random_access_iterator_tag{};190 } else if constexpr (bidirectional_range<_Base>) {191 return bidirectional_iterator_tag{};192 } else if constexpr (forward_range<_Base>) {193 return forward_iterator_tag{};194 } else {195 return input_iterator_tag{};196 }197 }198 199public:200 using iterator_concept = decltype(__iterator::__get_iterator_concept());201 using value_type = remove_cvref_t<tuple_element_t<_Np, range_value_t<_Base>>>;202 using difference_type = range_difference_t<_Base>;203 204 _LIBCPP_HIDE_FROM_ABI __iterator()205 requires default_initializable<iterator_t<_Base>>206 = default;207 208 _LIBCPP_HIDE_FROM_ABI constexpr explicit __iterator(iterator_t<_Base> __current) : __current_(std::move(__current)) {}209 210 _LIBCPP_HIDE_FROM_ABI constexpr __iterator(__iterator<!_Const> __i)211 requires _Const && convertible_to<iterator_t<_View>, iterator_t<_Base>>212 : __current_(std::move(__i.__current_)) {}213 214 _LIBCPP_HIDE_FROM_ABI constexpr const iterator_t<_Base>& base() const& noexcept { return __current_; }215 216 _LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_Base> base() && { return std::move(__current_); }217 218 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator*() const { return __get_element(__current_); }219 220 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() {221 ++__current_;222 return *this;223 }224 225 _LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++__current_; }226 227 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int)228 requires forward_range<_Base>229 {230 auto __temp = *this;231 ++__current_;232 return __temp;233 }234 235 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--()236 requires bidirectional_range<_Base>237 {238 --__current_;239 return *this;240 }241 242 _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int)243 requires bidirectional_range<_Base>244 {245 auto __temp = *this;246 --__current_;247 return __temp;248 }249 250 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator+=(difference_type __n)251 requires random_access_range<_Base>252 {253 __current_ += __n;254 return *this;255 }256 257 _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator-=(difference_type __n)258 requires random_access_range<_Base>259 {260 __current_ -= __n;261 return *this;262 }263 264 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator[](difference_type __n) const265 requires random_access_range<_Base>266 {267 return __get_element(__current_ + __n);268 }269 270 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)271 requires equality_comparable<iterator_t<_Base>>272 {273 return __x.__current_ == __y.__current_;274 }275 276 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(const __iterator& __x, const __iterator& __y)277 requires random_access_range<_Base>278 {279 return __x.__current_ < __y.__current_;280 }281 282 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(const __iterator& __x, const __iterator& __y)283 requires random_access_range<_Base>284 {285 return __y < __x;286 }287 288 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y)289 requires random_access_range<_Base>290 {291 return !(__y < __x);292 }293 294 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y)295 requires random_access_range<_Base>296 {297 return !(__x < __y);298 }299 300 _LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)301 requires random_access_range<_Base> && three_way_comparable<iterator_t<_Base>>302 {303 return __x.__current_ <=> __y.__current_;304 }305 306 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(const __iterator& __x, difference_type __y)307 requires random_access_range<_Base>308 {309 return __iterator{__x} += __y;310 }311 312 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(difference_type __x, const __iterator& __y)313 requires random_access_range<_Base>314 {315 return __y + __x;316 }317 318 _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator-(const __iterator& __x, difference_type __y)319 requires random_access_range<_Base>320 {321 return __iterator{__x} -= __y;322 }323 324 _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)325 requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>326 {327 return __x.__current_ - __y.__current_;328 }329};330 331template <input_range _View, size_t _Np>332 requires view<_View> && __has_tuple_element<range_value_t<_View>, _Np> &&333 __has_tuple_element<remove_reference_t<range_reference_t<_View>>, _Np> &&334 __returnable_element<range_reference_t<_View>, _Np>335template <bool _Const>336class elements_view<_View, _Np>::__sentinel {337private:338 using _Base _LIBCPP_NODEBUG = __maybe_const<_Const, _View>;339 _LIBCPP_NO_UNIQUE_ADDRESS sentinel_t<_Base> __end_ = sentinel_t<_Base>();340 341 template <bool>342 friend class __sentinel;343 344 template <bool _AnyConst>345 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __get_current(const __iterator<_AnyConst>& __iter) {346 return (__iter.__current_);347 }348 349public:350 _LIBCPP_HIDE_FROM_ABI __sentinel() = default;351 352 _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(sentinel_t<_Base> __end) : __end_(std::move(__end)) {}353 354 _LIBCPP_HIDE_FROM_ABI constexpr __sentinel(__sentinel<!_Const> __other)355 requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>356 : __end_(std::move(__other.__end_)) {}357 358 _LIBCPP_HIDE_FROM_ABI constexpr sentinel_t<_Base> base() const { return __end_; }359 360 template <bool _OtherConst>361 requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>362 _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {363 return __get_current(__x) == __y.__end_;364 }365 366 template <bool _OtherConst>367 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>368 _LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>369 operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {370 return __get_current(__x) - __y.__end_;371 }372 373 template <bool _OtherConst>374 requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>375 _LIBCPP_HIDE_FROM_ABI friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>376 operator-(const __sentinel& __x, const __iterator<_OtherConst>& __y) {377 return __x.__end_ - __get_current(__y);378 }379};380 381template <class _Tp, size_t _Np>382inline constexpr bool enable_borrowed_range<elements_view<_Tp, _Np>> = enable_borrowed_range<_Tp>;383 384template <class _Tp>385using keys_view = elements_view<_Tp, 0>;386template <class _Tp>387using values_view = elements_view<_Tp, 1>;388 389namespace views {390namespace __elements {391 392template <size_t _Np>393struct __fn : __range_adaptor_closure<__fn<_Np>> {394 template <class _Range>395 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range) const396 /**/ noexcept(noexcept(elements_view<all_t<_Range&&>, _Np>(std::forward<_Range>(__range))))397 /*------*/ -> decltype(elements_view<all_t<_Range&&>, _Np>(std::forward<_Range>(__range))) {398 /*-------------*/ return elements_view<all_t<_Range&&>, _Np>(std::forward<_Range>(__range));399 }400};401} // namespace __elements402 403inline namespace __cpo {404template <size_t _Np>405inline constexpr auto elements = __elements::__fn<_Np>{};406inline constexpr auto keys = elements<0>;407inline constexpr auto values = elements<1>;408} // namespace __cpo409} // namespace views410} // namespace ranges411 412#endif // _LIBCPP_STD_VER >= 20413 414_LIBCPP_END_NAMESPACE_STD415 416_LIBCPP_POP_MACROS417 418#endif // _LIBCPP___RANGES_ELEMENTS_VIEW_H419