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_MINMAX_H 10 #define _LIBCPP___ALGORITHM_RANGES_MINMAX_H 11 12 #include <__algorithm/min_max_result.h> 13 #include <__algorithm/minmax_element.h> 14 #include <__assert> 15 #include <__concepts/copyable.h> 16 #include <__config> 17 #include <__functional/identity.h> 18 #include <__functional/invoke.h> 19 #include <__functional/ranges_operations.h> 20 #include <__iterator/concepts.h> 21 #include <__iterator/projected.h> 22 #include <__ranges/access.h> 23 #include <__ranges/concepts.h> 24 #include <__utility/forward.h> 25 #include <__utility/move.h> 26 #include <initializer_list> 27 28 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 29 # pragma GCC system_header 30 #endif 31 32 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) 33 34 _LIBCPP_BEGIN_NAMESPACE_STD 35 36 namespace ranges { 37 template <class _T1> 38 using minmax_result = min_max_result<_T1>; 39 40 namespace __minmax { 41 struct __fn { 42 template <class _Type, class _Proj = identity, 43 indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less> 44 _LIBCPP_HIDE_FROM_ABI constexpr ranges::minmax_result<const _Type&> 45 operator()(const _Type& __a, const _Type& __b, _Comp __comp = {}, _Proj __proj = {}) const { 46 if (std::invoke(__comp, std::invoke(__proj, __b), std::invoke(__proj, __a))) 47 return {__b, __a}; 48 return {__a, __b}; 49 } 50 51 template <copyable _Type, class _Proj = identity, 52 indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less> 53 _LIBCPP_HIDE_FROM_ABI constexpr 54 ranges::minmax_result<_Type> operator()(initializer_list<_Type> __il, _Comp __comp = {}, _Proj __proj = {}) const { 55 _LIBCPP_ASSERT(__il.begin() != __il.end(), "initializer_list has to contain at least one element"); 56 auto __iters = std::__minmax_element_impl(__il.begin(), __il.end(), __comp, __proj); 57 return ranges::minmax_result<_Type> { *__iters.first, *__iters.second }; 58 } 59 60 template <input_range _Range, class _Proj = identity, 61 indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>> _Comp = ranges::less> 62 requires indirectly_copyable_storable<iterator_t<_Range>, range_value_t<_Range>*> 63 _LIBCPP_HIDE_FROM_ABI constexpr 64 ranges::minmax_result<range_value_t<_Range>> operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const { 65 auto __first = ranges::begin(__r); 66 auto __last = ranges::end(__r); 67 using _ValueT = range_value_t<_Range>; 68 69 _LIBCPP_ASSERT(__first != __last, "range has to contain at least one element"); 70 71 if constexpr (forward_range<_Range>) { 72 auto __result = std::__minmax_element_impl(__first, __last, __comp, __proj); 73 return {*__result.first, *__result.second}; 74 } else { 75 // input_iterators can't be copied, so the implementation for input_iterators has to store 76 // the values instead of a pointer to the correct values 77 auto __less = [&](auto&& __a, auto&& __b) -> bool { 78 return std::invoke(__comp, std::invoke(__proj, std::forward<decltype(__a)>(__a)), 79 std::invoke(__proj, std::forward<decltype(__b)>(__b))); 80 }; 81 82 ranges::minmax_result<_ValueT> __result = {*__first, __result.min}; 83 if (__first == __last || ++__first == __last) 84 return __result; 85 86 if (__less(*__first, __result.min)) 87 __result.min = *__first; 88 else 89 __result.max = *__first; 90 91 while (++__first != __last) { 92 _ValueT __i = *__first; 93 if (++__first == __last) { 94 if (__less(__i, __result.min)) 95 __result.min = __i; 96 else if (!__less(__i, __result.max)) 97 __result.max = __i; 98 return __result; 99 } 100 101 if (__less(*__first, __i)) { 102 if (__less(*__first, __result.min)) 103 __result.min = *__first; 104 if (!__less(__i, __result.max)) 105 __result.max = std::move(__i); 106 } else { 107 if (__less(__i, __result.min)) 108 __result.min = std::move(__i); 109 if (!__less(*__first, __result.max)) 110 __result.max = *__first; 111 } 112 } 113 return __result; 114 } 115 } 116 }; 117 } // namespace __minmax 118 119 inline namespace __cpo { 120 inline constexpr auto minmax = __minmax::__fn{}; 121 } // namespace __cpo 122 } // namespace ranges 123 124 _LIBCPP_END_NAMESPACE_STD 125 126 #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) 127 128 #endif // _LIBCPP___ALGORITHM_RANGES_MINMAX_H 129