6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
72 lines
2.1 KiB
C++
72 lines
2.1 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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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___RANGES_EMPTY_H
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#define _LIBCPP___RANGES_EMPTY_H
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#include <__concepts/class_or_enum.h>
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#include <__config>
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#include <__iterator/concepts.h>
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#include <__ranges/access.h>
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#include <__ranges/size.h>
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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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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER >= 20
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// [range.prim.empty]
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namespace ranges {
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namespace __empty {
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template <class _Tp>
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concept __member_empty = requires(_Tp&& __t) { bool(__t.empty()); };
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template <class _Tp>
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concept __can_invoke_size = !__member_empty<_Tp> && requires(_Tp&& __t) { ranges::size(__t); };
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template <class _Tp>
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concept __can_compare_begin_end = !__member_empty<_Tp> && !__can_invoke_size<_Tp> && requires(_Tp&& __t) {
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bool(ranges::begin(__t) == ranges::end(__t));
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{ ranges::begin(__t) } -> forward_iterator;
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};
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struct __fn {
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template <__member_empty _Tp>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_Tp&& __t) const noexcept(noexcept(bool(__t.empty()))) {
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return bool(__t.empty());
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}
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template <__can_invoke_size _Tp>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_Tp&& __t) const noexcept(noexcept(ranges::size(__t))) {
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return ranges::size(__t) == 0;
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}
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template <__can_compare_begin_end _Tp>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_Tp&& __t) const
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noexcept(noexcept(bool(ranges::begin(__t) == ranges::end(__t)))) {
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return ranges::begin(__t) == ranges::end(__t);
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}
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};
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} // namespace __empty
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inline namespace __cpo {
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inline constexpr auto empty = __empty::__fn{};
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} // namespace __cpo
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} // namespace ranges
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#endif // _LIBCPP_STD_VER >= 20
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___RANGES_EMPTY_H
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