1fe6060f1SDimitry Andric // -*- C++ -*- 2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3fe6060f1SDimitry Andric // 4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7fe6060f1SDimitry Andric // 8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9bdd1243dSDimitry Andric 10fe6060f1SDimitry Andric #ifndef _LIBCPP___ITERATOR_PROJECTED_H 11fe6060f1SDimitry Andric #define _LIBCPP___ITERATOR_PROJECTED_H 12fe6060f1SDimitry Andric 13fe6060f1SDimitry Andric #include <__config> 14fe6060f1SDimitry Andric #include <__iterator/concepts.h> 15*5f757f3fSDimitry Andric #include <__iterator/incrementable_traits.h> // iter_difference_t 16bdd1243dSDimitry Andric #include <__type_traits/remove_cvref.h> 17fe6060f1SDimitry Andric 18fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19fe6060f1SDimitry Andric # pragma GCC system_header 20fe6060f1SDimitry Andric #endif 21fe6060f1SDimitry Andric 22fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 23fe6060f1SDimitry Andric 2406c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 25fe6060f1SDimitry Andric 26*5f757f3fSDimitry Andric template <class _It, class _Proj> 27*5f757f3fSDimitry Andric struct __projected_impl { 28*5f757f3fSDimitry Andric struct __type { 29fe6060f1SDimitry Andric using value_type = remove_cvref_t<indirect_result_t<_Proj&, _It>>; 30fe6060f1SDimitry Andric indirect_result_t<_Proj&, _It> operator*() const; // not defined 31fe6060f1SDimitry Andric }; 32*5f757f3fSDimitry Andric }; 33fe6060f1SDimitry Andric 34fe6060f1SDimitry Andric template <weakly_incrementable _It, class _Proj> 35*5f757f3fSDimitry Andric struct __projected_impl<_It, _Proj> { 36*5f757f3fSDimitry Andric struct __type { 37*5f757f3fSDimitry Andric using value_type = remove_cvref_t<indirect_result_t<_Proj&, _It>>; 38fe6060f1SDimitry Andric using difference_type = iter_difference_t<_It>; 39*5f757f3fSDimitry Andric indirect_result_t<_Proj&, _It> operator*() const; // not defined 40fe6060f1SDimitry Andric }; 41*5f757f3fSDimitry Andric }; 42*5f757f3fSDimitry Andric 43*5f757f3fSDimitry Andric // Note that we implement std::projected in a way that satisfies P2538R1 even in standard 44*5f757f3fSDimitry Andric // modes before C++26 to avoid breaking the ABI between standard modes (even though ABI 45*5f757f3fSDimitry Andric // breaks with std::projected are expected to have essentially no impact). 46*5f757f3fSDimitry Andric template <indirectly_readable _It, indirectly_regular_unary_invocable<_It> _Proj> 47*5f757f3fSDimitry Andric using projected = typename __projected_impl<_It, _Proj>::__type; 48fe6060f1SDimitry Andric 4906c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 50fe6060f1SDimitry Andric 51fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 52fe6060f1SDimitry Andric 53fe6060f1SDimitry Andric #endif // _LIBCPP___ITERATOR_PROJECTED_H 54