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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
#define _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
#include <__algorithm/comp.h>
#include <__config>
#include <__functional/identity.h>
#include <__iterator/iterator_traits.h>
#include <__utility/pair.h>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Comp, class _Proj>
class _MinmaxElementLessFunc {
_Comp& __comp_;
_Proj& __proj_;
public:
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
_MinmaxElementLessFunc(_Comp& __comp, _Proj& __proj) : __comp_(__comp), __proj_(__proj) {}
template <class _Iter>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
bool operator()(_Iter& __it1, _Iter& __it2) {
return std::__invoke(__comp_, std::__invoke(__proj_, *__it1), std::__invoke(__proj_, *__it2));
}
};
template <class _Iter, class _Sent, class _Proj, class _Comp>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
pair<_Iter, _Iter> __minmax_element_impl(_Iter __first, _Sent __last, _Comp& __comp, _Proj& __proj) {
auto __less = _MinmaxElementLessFunc<_Comp, _Proj>(__comp, __proj);
pair<_Iter, _Iter> __result(__first, __first);
if (__first == __last || ++__first == __last)
return __result;
if (__less(__first, __result.first))
__result.first = __first;
else
__result.second = __first;
while (++__first != __last) {
_Iter __i = __first;
if (++__first == __last) {
if (__less(__i, __result.first))
__result.first = __i;
else if (!__less(__i, __result.second))
__result.second = __i;
return __result;
}
if (__less(__first, __i)) {
if (__less(__first, __result.first))
__result.first = __first;
if (!__less(__i, __result.second))
__result.second = __i;
} else {
if (__less(__i, __result.first))
__result.first = __i;
if (!__less(__first, __result.second))
__result.second = __first;
}
}
return __result;
}
template <class _ForwardIterator, class _Compare>
_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX11
pair<_ForwardIterator, _ForwardIterator>
minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) {
static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
"std::minmax_element requires a ForwardIterator");
static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value,
"The comparator has to be callable");
auto __proj = __identity();
return std::__minmax_element_impl(__first, __last, __comp, __proj);
}
template <class _ForwardIterator>
_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
pair<_ForwardIterator, _ForwardIterator> minmax_element(_ForwardIterator __first, _ForwardIterator __last) {
return std::minmax_element(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
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