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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_RANGES_MINMAX_H
- #define _LIBCPP___ALGORITHM_RANGES_MINMAX_H
- #include <__algorithm/min_max_result.h>
- #include <__algorithm/minmax_element.h>
- #include <__assert>
- #include <__concepts/copyable.h>
- #include <__concepts/same_as.h>
- #include <__config>
- #include <__functional/identity.h>
- #include <__functional/invoke.h>
- #include <__functional/ranges_operations.h>
- #include <__iterator/concepts.h>
- #include <__iterator/next.h>
- #include <__iterator/projected.h>
- #include <__ranges/access.h>
- #include <__ranges/concepts.h>
- #include <__type_traits/is_reference.h>
- #include <__type_traits/remove_cvref.h>
- #include <__utility/forward.h>
- #include <__utility/move.h>
- #include <__utility/pair.h>
- #include <initializer_list>
- #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
- # pragma GCC system_header
- #endif
- #if _LIBCPP_STD_VER >= 20
- _LIBCPP_PUSH_MACROS
- # include <__undef_macros>
- _LIBCPP_BEGIN_NAMESPACE_STD
- namespace ranges {
- template <class _T1>
- using minmax_result = min_max_result<_T1>;
- namespace __minmax {
- struct __fn {
- template <class _Type,
- class _Proj = identity,
- indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less>
- _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr ranges::minmax_result<const _Type&>
- operator()(_LIBCPP_LIFETIMEBOUND const _Type& __a,
- _LIBCPP_LIFETIMEBOUND const _Type& __b,
- _Comp __comp = {},
- _Proj __proj = {}) const {
- if (std::invoke(__comp, std::invoke(__proj, __b), std::invoke(__proj, __a)))
- return {__b, __a};
- return {__a, __b};
- }
- template <copyable _Type,
- class _Proj = identity,
- indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less>
- _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr ranges::minmax_result<_Type>
- operator()(initializer_list<_Type> __il, _Comp __comp = {}, _Proj __proj = {}) const {
- _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
- __il.begin() != __il.end(), "initializer_list has to contain at least one element");
- auto __iters = std::__minmax_element_impl(__il.begin(), __il.end(), __comp, __proj);
- return ranges::minmax_result<_Type>{*__iters.first, *__iters.second};
- }
- template <input_range _Range,
- class _Proj = identity,
- indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>> _Comp = ranges::less>
- requires indirectly_copyable_storable<iterator_t<_Range>, range_value_t<_Range>*>
- _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr ranges::minmax_result<range_value_t<_Range>>
- operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
- auto __first = ranges::begin(__r);
- auto __last = ranges::end(__r);
- using _ValueT = range_value_t<_Range>;
- _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__first != __last, "range has to contain at least one element");
- if constexpr (forward_range<_Range>) {
- // Special-case the one element case. Avoid repeatedly initializing objects from the result of an iterator
- // dereference when doing so might not be idempotent. The `if constexpr` avoids the extra branch in cases where
- // it's not needed.
- if constexpr (!same_as<remove_cvref_t<range_reference_t<_Range>>, _ValueT> ||
- is_rvalue_reference_v<range_reference_t<_Range>>) {
- if (ranges::next(__first) == __last) {
- // During initialization, members are allowed to refer to already initialized members
- // (see http://eel.is/c++draft/dcl.init.aggr#6)
- minmax_result<_ValueT> __result = {*__first, __result.min};
- return __result;
- }
- }
- auto __result = std::__minmax_element_impl(__first, __last, __comp, __proj);
- return {*__result.first, *__result.second};
- } else {
- // input_iterators can't be copied, so the implementation for input_iterators has to store
- // the values instead of a pointer to the correct values
- auto __less = [&](auto&& __a, auto&& __b) -> bool {
- return std::invoke(__comp,
- std::invoke(__proj, std::forward<decltype(__a)>(__a)),
- std::invoke(__proj, std::forward<decltype(__b)>(__b)));
- };
- // During initialization, members are allowed to refer to already initialized members
- // (see http://eel.is/c++draft/dcl.init.aggr#6)
- ranges::minmax_result<_ValueT> __result = {*__first, __result.min};
- if (__first == __last || ++__first == __last)
- return __result;
- if (__less(*__first, __result.min))
- __result.min = *__first;
- else
- __result.max = *__first;
- while (++__first != __last) {
- _ValueT __i = *__first;
- if (++__first == __last) {
- if (__less(__i, __result.min))
- __result.min = __i;
- else if (!__less(__i, __result.max))
- __result.max = __i;
- return __result;
- }
- if (__less(*__first, __i)) {
- if (__less(*__first, __result.min))
- __result.min = *__first;
- if (!__less(__i, __result.max))
- __result.max = std::move(__i);
- } else {
- if (__less(__i, __result.min))
- __result.min = std::move(__i);
- if (!__less(*__first, __result.max))
- __result.max = *__first;
- }
- }
- return __result;
- }
- }
- };
- } // namespace __minmax
- inline namespace __cpo {
- inline constexpr auto minmax = __minmax::__fn{};
- } // namespace __cpo
- } // namespace ranges
- _LIBCPP_END_NAMESPACE_STD
- _LIBCPP_POP_MACROS
- #endif // _LIBCPP_STD_VER >= 20
- #endif // _LIBCPP___ALGORITHM_RANGES_MINMAX_H
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