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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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___CXX03___ALGORITHM_MINMAX_ELEMENT_H10#define _LIBCPP___CXX03___ALGORITHM_MINMAX_ELEMENT_H11 12#include <__cxx03/__algorithm/comp.h>13#include <__cxx03/__config>14#include <__cxx03/__functional/identity.h>15#include <__cxx03/__iterator/iterator_traits.h>16#include <__cxx03/__type_traits/invoke.h>17#include <__cxx03/__type_traits/is_callable.h>18#include <__cxx03/__utility/pair.h>19 20#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)21# pragma GCC system_header22#endif23 24_LIBCPP_BEGIN_NAMESPACE_STD25 26template <class _Comp, class _Proj>27class _MinmaxElementLessFunc {28 _Comp& __comp_;29 _Proj& __proj_;30 31public:32 _LIBCPP_HIDE_FROM_ABI _MinmaxElementLessFunc(_Comp& __comp, _Proj& __proj) : __comp_(__comp), __proj_(__proj) {}33 34 template <class _Iter>35 _LIBCPP_HIDE_FROM_ABI bool operator()(_Iter& __it1, _Iter& __it2) {36 return std::__invoke(__comp_, std::__invoke(__proj_, *__it1), std::__invoke(__proj_, *__it2));37 }38};39 40template <class _Iter, class _Sent, class _Proj, class _Comp>41_LIBCPP_HIDE_FROM_ABI pair<_Iter, _Iter>42__minmax_element_impl(_Iter __first, _Sent __last, _Comp& __comp, _Proj& __proj) {43 auto __less = _MinmaxElementLessFunc<_Comp, _Proj>(__comp, __proj);44 45 pair<_Iter, _Iter> __result(__first, __first);46 if (__first == __last || ++__first == __last)47 return __result;48 49 if (__less(__first, __result.first))50 __result.first = __first;51 else52 __result.second = __first;53 54 while (++__first != __last) {55 _Iter __i = __first;56 if (++__first == __last) {57 if (__less(__i, __result.first))58 __result.first = __i;59 else if (!__less(__i, __result.second))60 __result.second = __i;61 return __result;62 }63 64 if (__less(__first, __i)) {65 if (__less(__first, __result.first))66 __result.first = __first;67 if (!__less(__i, __result.second))68 __result.second = __i;69 } else {70 if (__less(__i, __result.first))71 __result.first = __i;72 if (!__less(__first, __result.second))73 __result.second = __first;74 }75 }76 77 return __result;78}79 80template <class _ForwardIterator, class _Compare>81_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI pair<_ForwardIterator, _ForwardIterator>82minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) {83 static_assert(84 __has_forward_iterator_category<_ForwardIterator>::value, "std::minmax_element requires a ForwardIterator");85 static_assert(86 __is_callable<_Compare, decltype(*__first), decltype(*__first)>::value, "The comparator has to be callable");87 auto __proj = __identity();88 return std::__minmax_element_impl(__first, __last, __comp, __proj);89}90 91template <class _ForwardIterator>92_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI pair<_ForwardIterator, _ForwardIterator>93minmax_element(_ForwardIterator __first, _ForwardIterator __last) {94 return std::minmax_element(__first, __last, __less<>());95}96 97_LIBCPP_END_NAMESPACE_STD98 99#endif // _LIBCPP___CXX03___ALGORITHM_MINMAX_ELEMENT_H100