1349cc55cSDimitry Andric // -*- C++ -*- 2349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 3349cc55cSDimitry Andric // 4349cc55cSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5349cc55cSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6349cc55cSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7349cc55cSDimitry Andric // 8349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 9bdd1243dSDimitry Andric 10349cc55cSDimitry Andric #ifndef _LIBCPP___RANGES_COUNTED_H 11349cc55cSDimitry Andric #define _LIBCPP___RANGES_COUNTED_H 12349cc55cSDimitry Andric 130eae32dcSDimitry Andric #include <__concepts/convertible_to.h> 14349cc55cSDimitry Andric #include <__config> 15349cc55cSDimitry Andric #include <__iterator/concepts.h> 16349cc55cSDimitry Andric #include <__iterator/counted_iterator.h> 17349cc55cSDimitry Andric #include <__iterator/default_sentinel.h> 18349cc55cSDimitry Andric #include <__iterator/incrementable_traits.h> 19349cc55cSDimitry Andric #include <__iterator/iterator_traits.h> 20349cc55cSDimitry Andric #include <__memory/pointer_traits.h> 21349cc55cSDimitry Andric #include <__ranges/subrange.h> 22*06c3fb27SDimitry Andric #include <__type_traits/decay.h> 23349cc55cSDimitry Andric #include <__utility/forward.h> 24349cc55cSDimitry Andric #include <__utility/move.h> 25*06c3fb27SDimitry Andric #include <cstddef> 26349cc55cSDimitry Andric #include <span> 27349cc55cSDimitry Andric 28349cc55cSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 29349cc55cSDimitry Andric # pragma GCC system_header 30349cc55cSDimitry Andric #endif 31349cc55cSDimitry Andric 32349cc55cSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 33349cc55cSDimitry Andric 34*06c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 35349cc55cSDimitry Andric 36349cc55cSDimitry Andric namespace ranges::views { 37349cc55cSDimitry Andric 38349cc55cSDimitry Andric namespace __counted { 39349cc55cSDimitry Andric 40349cc55cSDimitry Andric struct __fn { 410eae32dcSDimitry Andric template<contiguous_iterator _It> 42349cc55cSDimitry Andric _LIBCPP_HIDE_FROM_ABI 430eae32dcSDimitry Andric static constexpr auto __go(_It __it, iter_difference_t<_It> __count) 4481ad6265SDimitry Andric noexcept(noexcept(span(std::to_address(__it), static_cast<size_t>(__count)))) 450eae32dcSDimitry Andric // Deliberately omit return-type SFINAE, because to_address is not SFINAE-friendly 4681ad6265SDimitry Andric { return span(std::to_address(__it), static_cast<size_t>(__count)); } 47349cc55cSDimitry Andric 480eae32dcSDimitry Andric template<random_access_iterator _It> 49349cc55cSDimitry Andric _LIBCPP_HIDE_FROM_ABI 500eae32dcSDimitry Andric static constexpr auto __go(_It __it, iter_difference_t<_It> __count) 510eae32dcSDimitry Andric noexcept(noexcept(subrange(__it, __it + __count))) 520eae32dcSDimitry Andric -> decltype( subrange(__it, __it + __count)) 530eae32dcSDimitry Andric { return subrange(__it, __it + __count); } 54349cc55cSDimitry Andric 550eae32dcSDimitry Andric template<class _It> 56349cc55cSDimitry Andric _LIBCPP_HIDE_FROM_ABI 570eae32dcSDimitry Andric static constexpr auto __go(_It __it, iter_difference_t<_It> __count) 5881ad6265SDimitry Andric noexcept(noexcept(subrange(counted_iterator(std::move(__it), __count), default_sentinel))) 5981ad6265SDimitry Andric -> decltype( subrange(counted_iterator(std::move(__it), __count), default_sentinel)) 6081ad6265SDimitry Andric { return subrange(counted_iterator(std::move(__it), __count), default_sentinel); } 610eae32dcSDimitry Andric 620eae32dcSDimitry Andric template<class _It, convertible_to<iter_difference_t<_It>> _Diff> 630eae32dcSDimitry Andric requires input_or_output_iterator<decay_t<_It>> 640eae32dcSDimitry Andric [[nodiscard]] _LIBCPP_HIDE_FROM_ABI 650eae32dcSDimitry Andric constexpr auto operator()(_It&& __it, _Diff&& __count) const 6681ad6265SDimitry Andric noexcept(noexcept(__go(std::forward<_It>(__it), std::forward<_Diff>(__count)))) 6781ad6265SDimitry Andric -> decltype( __go(std::forward<_It>(__it), std::forward<_Diff>(__count))) 6881ad6265SDimitry Andric { return __go(std::forward<_It>(__it), std::forward<_Diff>(__count)); } 69349cc55cSDimitry Andric }; 700eae32dcSDimitry Andric 710eae32dcSDimitry Andric } // namespace __counted 72349cc55cSDimitry Andric 73349cc55cSDimitry Andric inline namespace __cpo { 74349cc55cSDimitry Andric inline constexpr auto counted = __counted::__fn{}; 75349cc55cSDimitry Andric } // namespace __cpo 76349cc55cSDimitry Andric 77349cc55cSDimitry Andric } // namespace ranges::views 78349cc55cSDimitry Andric 79*06c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 80349cc55cSDimitry Andric 81349cc55cSDimitry Andric _LIBCPP_END_NAMESPACE_STD 82349cc55cSDimitry Andric 83349cc55cSDimitry Andric #endif // _LIBCPP___RANGES_COUNTED_H 84