1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H 10 #define _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H 11 12 #include <__config> 13 #include <__functional/identity.h> 14 #include <__functional/invoke.h> 15 #include <__functional/ranges_operations.h> 16 #include <__iterator/concepts.h> 17 #include <__iterator/projected.h> 18 #include <__ranges/access.h> 19 #include <__ranges/concepts.h> 20 #include <__ranges/dangling.h> 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 # pragma GCC system_header 24 #endif 25 26 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) 27 28 _LIBCPP_BEGIN_NAMESPACE_STD 29 30 namespace ranges { 31 namespace __max_element { 32 struct __fn { 33 template <class _Ip, class _Sp, class _Proj, class _Comp> 34 _LIBCPP_HIDE_FROM_ABI static constexpr 35 _Ip __go(_Ip __first, _Sp __last, _Comp& __comp, _Proj& __proj) { 36 if (__first == __last) 37 return __first; 38 39 _Ip __i = __first; 40 while (++__i != __last) 41 if (std::invoke(__comp, std::invoke(__proj, *__first), std::invoke(__proj, *__i))) 42 __first = __i; 43 return __first; 44 } 45 46 template <forward_iterator _Ip, sentinel_for<_Ip> _Sp, class _Proj = identity, 47 indirect_strict_weak_order<projected<_Ip, _Proj>> _Comp = ranges::less> 48 _LIBCPP_HIDE_FROM_ABI constexpr 49 _Ip operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const { 50 return __go(__first, __last, __comp, __proj); 51 } 52 53 template <forward_range _Rp, class _Proj = identity, 54 indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less> 55 _LIBCPP_HIDE_FROM_ABI constexpr 56 borrowed_iterator_t<_Rp> operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const { 57 return __go(ranges::begin(__r), ranges::end(__r), __comp, __proj); 58 } 59 }; 60 } // namespace __max_element 61 62 inline namespace __cpo { 63 inline constexpr auto max_element = __max_element::__fn{}; 64 } // namespace __cpo 65 } // namespace ranges 66 67 _LIBCPP_END_NAMESPACE_STD 68 69 #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) 70 71 #endif // _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H 72