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_H 10 #define _LIBCPP___ALGORITHM_RANGES_MAX_H 11 12 #include <__algorithm/ranges_min_element.h> 13 #include <__assert> 14 #include <__concepts/copyable.h> 15 #include <__config> 16 #include <__functional/identity.h> 17 #include <__functional/invoke.h> 18 #include <__functional/ranges_operations.h> 19 #include <__iterator/concepts.h> 20 #include <__iterator/projected.h> 21 #include <__ranges/access.h> 22 #include <__ranges/concepts.h> 23 #include <__type_traits/is_trivially_copyable.h> 24 #include <__utility/move.h> 25 #include <initializer_list> 26 27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 28 # pragma GCC system_header 29 #endif 30 31 #if _LIBCPP_STD_VER >= 20 32 33 _LIBCPP_PUSH_MACROS 34 # include <__undef_macros> 35 36 _LIBCPP_BEGIN_NAMESPACE_STD 37 38 namespace ranges { 39 namespace __max { 40 struct __fn { 41 template <class _Tp, 42 class _Proj = identity, 43 indirect_strict_weak_order<projected<const _Tp*, _Proj>> _Comp = ranges::less> 44 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr const _Tp& 45 operator()(_LIBCPP_LIFETIMEBOUND const _Tp& __a, 46 _LIBCPP_LIFETIMEBOUND const _Tp& __b, 47 _Comp __comp = {}, 48 _Proj __proj = {}) const { 49 return std::invoke(__comp, std::invoke(__proj, __a), std::invoke(__proj, __b)) ? __b : __a; 50 } 51 52 template <copyable _Tp, 53 class _Proj = identity, 54 indirect_strict_weak_order<projected<const _Tp*, _Proj>> _Comp = ranges::less> 55 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr _Tp 56 operator()(initializer_list<_Tp> __il, _Comp __comp = {}, _Proj __proj = {}) const { 57 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS( 58 __il.begin() != __il.end(), "initializer_list must contain at least one element"); 59 60 auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool { return std::invoke(__comp, __rhs, __lhs); }; 61 return *ranges::__min_element_impl(__il.begin(), __il.end(), __comp_lhs_rhs_swapped, __proj); 62 } 63 64 template <input_range _Rp, 65 class _Proj = identity, 66 indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less> 67 requires indirectly_copyable_storable<iterator_t<_Rp>, range_value_t<_Rp>*> 68 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr range_value_t<_Rp> 69 operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const { 70 auto __first = ranges::begin(__r); 71 auto __last = ranges::end(__r); 72 73 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__first != __last, "range must contain at least one element"); 74 75 if constexpr (forward_range<_Rp> && !__is_cheap_to_copy<range_value_t<_Rp>>) { 76 auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool { 77 return std::invoke(__comp, __rhs, __lhs); 78 }; 79 return *ranges::__min_element_impl(std::move(__first), std::move(__last), __comp_lhs_rhs_swapped, __proj); 80 } else { 81 range_value_t<_Rp> __result = *__first; 82 while (++__first != __last) { 83 if (std::invoke(__comp, std::invoke(__proj, __result), std::invoke(__proj, *__first))) 84 __result = *__first; 85 } 86 return __result; 87 } 88 } 89 }; 90 } // namespace __max 91 92 inline namespace __cpo { 93 inline constexpr auto max = __max::__fn{}; 94 } // namespace __cpo 95 } // namespace ranges 96 97 _LIBCPP_END_NAMESPACE_STD 98 99 _LIBCPP_POP_MACROS 100 101 #endif // _LIBCPP_STD_VER >= 20 && 102 103 #endif // _LIBCPP___ALGORITHM_RANGES_MAX_H 104