129 lines
4.6 KiB
C++
129 lines
4.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___ALGORITHM_RANGES_MINMAX_H
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#define _LIBCPP___ALGORITHM_RANGES_MINMAX_H
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#include <__algorithm/min_max_result.h>
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#include <__algorithm/minmax_element.h>
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#include <__assert>
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#include <__concepts/copyable.h>
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#include <__config>
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#include <__functional/identity.h>
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#include <__functional/invoke.h>
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#include <__functional/ranges_operations.h>
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#include <__iterator/concepts.h>
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#include <__iterator/projected.h>
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#include <__ranges/access.h>
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#include <__ranges/concepts.h>
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#include <__utility/forward.h>
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#include <__utility/move.h>
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#include <initializer_list>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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_LIBCPP_BEGIN_NAMESPACE_STD
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namespace ranges {
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template <class _T1>
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using minmax_result = min_max_result<_T1>;
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namespace __minmax {
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struct __fn {
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template <class _Type, class _Proj = identity,
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indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less>
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_LIBCPP_HIDE_FROM_ABI constexpr ranges::minmax_result<const _Type&>
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operator()(const _Type& __a, const _Type& __b, _Comp __comp = {}, _Proj __proj = {}) const {
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if (std::invoke(__comp, std::invoke(__proj, __b), std::invoke(__proj, __a)))
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return {__b, __a};
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return {__a, __b};
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}
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template <copyable _Type, class _Proj = identity,
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indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less>
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_LIBCPP_HIDE_FROM_ABI constexpr
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ranges::minmax_result<_Type> operator()(initializer_list<_Type> __il, _Comp __comp = {}, _Proj __proj = {}) const {
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_LIBCPP_ASSERT(__il.begin() != __il.end(), "initializer_list has to contain at least one element");
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auto __iters = std::__minmax_element_impl(__il.begin(), __il.end(), __comp, __proj);
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return ranges::minmax_result<_Type> { *__iters.first, *__iters.second };
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}
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template <input_range _Range, class _Proj = identity,
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indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>> _Comp = ranges::less>
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requires indirectly_copyable_storable<iterator_t<_Range>, range_value_t<_Range>*>
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_LIBCPP_HIDE_FROM_ABI constexpr
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ranges::minmax_result<range_value_t<_Range>> operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
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auto __first = ranges::begin(__r);
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auto __last = ranges::end(__r);
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using _ValueT = range_value_t<_Range>;
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_LIBCPP_ASSERT(__first != __last, "range has to contain at least one element");
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if constexpr (forward_range<_Range>) {
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auto __result = std::__minmax_element_impl(__first, __last, __comp, __proj);
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return {*__result.first, *__result.second};
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} else {
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// input_iterators can't be copied, so the implementation for input_iterators has to store
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// the values instead of a pointer to the correct values
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auto __less = [&](auto&& __a, auto&& __b) -> bool {
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return std::invoke(__comp, std::invoke(__proj, std::forward<decltype(__a)>(__a)),
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std::invoke(__proj, std::forward<decltype(__b)>(__b)));
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};
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ranges::minmax_result<_ValueT> __result = {*__first, __result.min};
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if (__first == __last || ++__first == __last)
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return __result;
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if (__less(*__first, __result.min))
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__result.min = *__first;
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else
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__result.max = *__first;
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while (++__first != __last) {
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_ValueT __i = *__first;
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if (++__first == __last) {
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if (__less(__i, __result.min))
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__result.min = __i;
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else if (!__less(__i, __result.max))
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__result.max = __i;
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return __result;
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}
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if (__less(*__first, __i)) {
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if (__less(*__first, __result.min))
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__result.min = *__first;
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if (!__less(__i, __result.max))
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__result.max = std::move(__i);
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} else {
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if (__less(__i, __result.min))
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__result.min = std::move(__i);
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if (!__less(*__first, __result.max))
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__result.max = *__first;
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}
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}
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return __result;
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}
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}
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};
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} // namespace __minmax
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inline namespace __cpo {
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inline constexpr auto minmax = __minmax::__fn{};
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} // namespace __cpo
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} // namespace ranges
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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#endif // _LIBCPP___ALGORITHM_RANGES_MINMAX_H
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