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Diffstat (limited to 'contrib/llvm-project/libcxx/include/__algorithm/ranges_minmax.h')
-rw-r--r-- | contrib/llvm-project/libcxx/include/__algorithm/ranges_minmax.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__algorithm/ranges_minmax.h b/contrib/llvm-project/libcxx/include/__algorithm/ranges_minmax.h new file mode 100644 index 000000000000..2f4bba0e7cc0 --- /dev/null +++ b/contrib/llvm-project/libcxx/include/__algorithm/ranges_minmax.h @@ -0,0 +1,133 @@ +//===----------------------------------------------------------------------===// +// +// 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 <__config> +#include <__functional/identity.h> +#include <__functional/invoke.h> +#include <__functional/ranges_operations.h> +#include <__iterator/concepts.h> +#include <__iterator/projected.h> +#include <__ranges/access.h> +#include <__ranges/concepts.h> +#include <__utility/forward.h> +#include <__utility/move.h> +#include <initializer_list> + +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +# pragma GCC system_header +#endif + +#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) + +_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_HIDE_FROM_ABI constexpr ranges::minmax_result<const _Type&> + operator()(const _Type& __a, 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_HIDE_FROM_ABI constexpr + ranges::minmax_result<_Type> operator()(initializer_list<_Type> __il, _Comp __comp = {}, _Proj __proj = {}) const { + _LIBCPP_ASSERT(__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_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(__first != __last, "range has to contain at least one element"); + + if constexpr (forward_range<_Range>) { + 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))); + }; + + 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 > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) + +#endif // _LIBCPP___ALGORITHM_RANGES_MINMAX_H |