| // -*- 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_SUBRANGE_H |
| #define _LIBCPP___RANGES_SUBRANGE_H |
| |
| #include <__concepts/constructible.h> |
| #include <__concepts/convertible_to.h> |
| #include <__concepts/copyable.h> |
| #include <__concepts/derived_from.h> |
| #include <__concepts/different_from.h> |
| #include <__config> |
| #include <__debug> |
| #include <__iterator/advance.h> |
| #include <__iterator/concepts.h> |
| #include <__iterator/incrementable_traits.h> |
| #include <__iterator/iterator_traits.h> |
| #include <__ranges/access.h> |
| #include <__ranges/concepts.h> |
| #include <__ranges/dangling.h> |
| #include <__ranges/enable_borrowed_range.h> |
| #include <__ranges/size.h> |
| #include <__ranges/view_interface.h> |
| #include <__tuple> |
| #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 !defined(_LIBCPP_HAS_NO_RANGES) |
| |
| namespace ranges { |
| template<class _From, class _To> |
| concept __convertible_to_non_slicing = |
| convertible_to<_From, _To> && |
| // If they're both pointers, they must have the same element type. |
| !(is_pointer_v<decay_t<_From>> && |
| is_pointer_v<decay_t<_To>> && |
| __different_from<remove_pointer_t<decay_t<_From>>, remove_pointer_t<decay_t<_To>>>); |
| |
| template<class _Tp> |
| concept __pair_like = |
| !is_reference_v<_Tp> && requires(_Tp __t) { |
| typename tuple_size<_Tp>::type; // Ensures `tuple_size<T>` is complete. |
| requires derived_from<tuple_size<_Tp>, integral_constant<size_t, 2>>; |
| typename tuple_element_t<0, remove_const_t<_Tp>>; |
| typename tuple_element_t<1, remove_const_t<_Tp>>; |
| { _VSTD::get<0>(__t) } -> convertible_to<const tuple_element_t<0, _Tp>&>; |
| { _VSTD::get<1>(__t) } -> convertible_to<const tuple_element_t<1, _Tp>&>; |
| }; |
| |
| template<class _Pair, class _Iter, class _Sent> |
| concept __pair_like_convertible_from = |
| !range<_Pair> && __pair_like<_Pair> && |
| constructible_from<_Pair, _Iter, _Sent> && |
| __convertible_to_non_slicing<_Iter, tuple_element_t<0, _Pair>> && |
| convertible_to<_Sent, tuple_element_t<1, _Pair>>; |
| |
| enum class _LIBCPP_ENUM_VIS subrange_kind : bool { unsized, sized }; |
| |
| template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent = _Iter, |
| subrange_kind _Kind = sized_sentinel_for<_Sent, _Iter> |
| ? subrange_kind::sized |
| : subrange_kind::unsized> |
| requires (_Kind == subrange_kind::sized || !sized_sentinel_for<_Sent, _Iter>) |
| class _LIBCPP_TEMPLATE_VIS subrange |
| : public view_interface<subrange<_Iter, _Sent, _Kind>> |
| { |
| private: |
| static constexpr bool _StoreSize = (_Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _Iter>); |
| static constexpr bool _MustProvideSizeAtConstruction = !_StoreSize; // just to improve compiler diagnostics |
| struct _Empty { constexpr _Empty(auto) noexcept { } }; |
| using _Size = conditional_t<_StoreSize, make_unsigned_t<iter_difference_t<_Iter>>, _Empty>; |
| [[no_unique_address]] _Iter __begin_ = _Iter(); |
| [[no_unique_address]] _Sent __end_ = _Sent(); |
| [[no_unique_address]] _Size __size_ = 0; |
| |
| public: |
| _LIBCPP_HIDE_FROM_ABI |
| subrange() requires default_initializable<_Iter> = default; |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent) |
| requires _MustProvideSizeAtConstruction |
| : __begin_(_VSTD::move(__iter)), __end_(std::move(__sent)) |
| { } |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent, |
| make_unsigned_t<iter_difference_t<_Iter>> __n) |
| requires (_Kind == subrange_kind::sized) |
| : __begin_(_VSTD::move(__iter)), __end_(std::move(__sent)), __size_(__n) |
| { |
| if constexpr (sized_sentinel_for<_Sent, _Iter>) |
| _LIBCPP_ASSERT((__end_ - __begin_) == static_cast<iter_difference_t<_Iter>>(__n), |
| "std::ranges::subrange was passed an invalid size hint"); |
| } |
| |
| template<__different_from<subrange> _Range> |
| requires borrowed_range<_Range> && |
| __convertible_to_non_slicing<iterator_t<_Range>, _Iter> && |
| convertible_to<sentinel_t<_Range>, _Sent> |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr subrange(_Range&& __range) |
| requires (!_StoreSize) |
| : subrange(ranges::begin(__range), ranges::end(__range)) |
| { } |
| |
| template<__different_from<subrange> _Range> |
| requires borrowed_range<_Range> && |
| __convertible_to_non_slicing<iterator_t<_Range>, _Iter> && |
| convertible_to<sentinel_t<_Range>, _Sent> |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr subrange(_Range&& __range) |
| requires _StoreSize && sized_range<_Range> |
| : subrange(__range, ranges::size(__range)) |
| { } |
| |
| template<borrowed_range _Range> |
| requires __convertible_to_non_slicing<iterator_t<_Range>, _Iter> && |
| convertible_to<sentinel_t<_Range>, _Sent> |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr subrange(_Range&& __range, make_unsigned_t<iter_difference_t<_Iter>> __n) |
| requires (_Kind == subrange_kind::sized) |
| : subrange(ranges::begin(__range), ranges::end(__range), __n) |
| { } |
| |
| template<__different_from<subrange> _Pair> |
| requires __pair_like_convertible_from<_Pair, const _Iter&, const _Sent&> |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr operator _Pair() const { |
| return _Pair(__begin_, __end_); |
| } |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr _Iter begin() const requires copyable<_Iter> { |
| return __begin_; |
| } |
| |
| [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Iter begin() requires (!copyable<_Iter>) { |
| return _VSTD::move(__begin_); |
| } |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr _Sent end() const { |
| return __end_; |
| } |
| |
| [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const { |
| return __begin_ == __end_; |
| } |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr make_unsigned_t<iter_difference_t<_Iter>> size() const |
| requires (_Kind == subrange_kind::sized) |
| { |
| if constexpr (_StoreSize) |
| return __size_; |
| else |
| return _VSTD::__to_unsigned_like(__end_ - __begin_); |
| } |
| |
| [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) const& |
| requires forward_iterator<_Iter> |
| { |
| auto __tmp = *this; |
| __tmp.advance(__n); |
| return __tmp; |
| } |
| |
| [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) && { |
| advance(__n); |
| return _VSTD::move(*this); |
| } |
| |
| [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange prev(iter_difference_t<_Iter> __n = 1) const |
| requires bidirectional_iterator<_Iter> |
| { |
| auto __tmp = *this; |
| __tmp.advance(-__n); |
| return __tmp; |
| } |
| |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr subrange& advance(iter_difference_t<_Iter> __n) { |
| if constexpr (bidirectional_iterator<_Iter>) { |
| if (__n < 0) { |
| ranges::advance(__begin_, __n); |
| if constexpr (_StoreSize) |
| __size_ += _VSTD::__to_unsigned_like(-__n); |
| return *this; |
| } |
| } |
| |
| auto __d = __n - ranges::advance(__begin_, __n, __end_); |
| if constexpr (_StoreSize) |
| __size_ -= _VSTD::__to_unsigned_like(__d); |
| return *this; |
| } |
| }; |
| |
| template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent> |
| subrange(_Iter, _Sent) -> subrange<_Iter, _Sent>; |
| |
| template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent> |
| subrange(_Iter, _Sent, make_unsigned_t<iter_difference_t<_Iter>>) |
| -> subrange<_Iter, _Sent, subrange_kind::sized>; |
| |
| template<borrowed_range _Range> |
| subrange(_Range&&) -> subrange<iterator_t<_Range>, sentinel_t<_Range>, |
| (sized_range<_Range> || sized_sentinel_for<sentinel_t<_Range>, iterator_t<_Range>>) |
| ? subrange_kind::sized : subrange_kind::unsized>; |
| |
| template<borrowed_range _Range> |
| subrange(_Range&&, make_unsigned_t<range_difference_t<_Range>>) |
| -> subrange<iterator_t<_Range>, sentinel_t<_Range>, subrange_kind::sized>; |
| |
| template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind> |
| requires (_Index < 2) |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr auto get(const subrange<_Iter, _Sent, _Kind>& __subrange) { |
| if constexpr (_Index == 0) |
| return __subrange.begin(); |
| else |
| return __subrange.end(); |
| } |
| |
| template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind> |
| requires (_Index < 2) |
| _LIBCPP_HIDE_FROM_ABI |
| constexpr auto get(subrange<_Iter, _Sent, _Kind>&& __subrange) { |
| if constexpr (_Index == 0) |
| return __subrange.begin(); |
| else |
| return __subrange.end(); |
| } |
| |
| template<class _Ip, class _Sp, subrange_kind _Kp> |
| inline constexpr bool enable_borrowed_range<subrange<_Ip, _Sp, _Kp>> = true; |
| |
| template<range _Rp> |
| using borrowed_subrange_t = _If<borrowed_range<_Rp>, subrange<iterator_t<_Rp>>, dangling>; |
| } // namespace ranges |
| |
| // [range.subrange.general] |
| |
| using ranges::get; |
| |
| // [ranges.syn] |
| |
| template<class _Ip, class _Sp, ranges::subrange_kind _Kp> |
| struct tuple_size<ranges::subrange<_Ip, _Sp, _Kp>> : integral_constant<size_t, 2> {}; |
| |
| template<class _Ip, class _Sp, ranges::subrange_kind _Kp> |
| struct tuple_element<0, ranges::subrange<_Ip, _Sp, _Kp>> { |
| using type = _Ip; |
| }; |
| |
| template<class _Ip, class _Sp, ranges::subrange_kind _Kp> |
| struct tuple_element<1, ranges::subrange<_Ip, _Sp, _Kp>> { |
| using type = _Sp; |
| }; |
| |
| template<class _Ip, class _Sp, ranges::subrange_kind _Kp> |
| struct tuple_element<0, const ranges::subrange<_Ip, _Sp, _Kp>> { |
| using type = _Ip; |
| }; |
| |
| template<class _Ip, class _Sp, ranges::subrange_kind _Kp> |
| struct tuple_element<1, const ranges::subrange<_Ip, _Sp, _Kp>> { |
| using type = _Sp; |
| }; |
| |
| #endif // !defined(_LIBCPP_HAS_NO_RANGES) |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___RANGES_SUBRANGE_H |