67432f2049
This is the first part of the "Freezing C++03 headers" proposal explained in https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc/77319/58. This patch mechanically copies the headers as of the LLVM 19.1 release into a subdirectory of libc++ so that we can start using these headers when building in C++03 mode. We are going to be backporting important changes to that copy of the headers until the LLVM 21 release. After the LLVM 21 release, only critical bugfixes will be fixed in the C++03 copy of the headers. This patch only performs a copy of the headers -- these headers are still unused by the rest of the codebase.
101 lines
3.3 KiB
C++
101 lines
3.3 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_MINMAX_ELEMENT_H
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#define _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
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#include <__algorithm/comp.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 <__iterator/iterator_traits.h>
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#include <__type_traits/is_callable.h>
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#include <__utility/pair.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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template <class _Comp, class _Proj>
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class _MinmaxElementLessFunc {
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_Comp& __comp_;
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_Proj& __proj_;
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public:
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _MinmaxElementLessFunc(_Comp& __comp, _Proj& __proj)
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: __comp_(__comp), __proj_(__proj) {}
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template <class _Iter>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(_Iter& __it1, _Iter& __it2) {
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return std::__invoke(__comp_, std::__invoke(__proj_, *__it1), std::__invoke(__proj_, *__it2));
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}
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};
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template <class _Iter, class _Sent, class _Proj, class _Comp>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter, _Iter>
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__minmax_element_impl(_Iter __first, _Sent __last, _Comp& __comp, _Proj& __proj) {
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auto __less = _MinmaxElementLessFunc<_Comp, _Proj>(__comp, __proj);
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pair<_Iter, _Iter> __result(__first, __first);
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if (__first == __last || ++__first == __last)
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return __result;
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if (__less(__first, __result.first))
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__result.first = __first;
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else
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__result.second = __first;
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while (++__first != __last) {
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_Iter __i = __first;
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if (++__first == __last) {
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if (__less(__i, __result.first))
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__result.first = __i;
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else if (!__less(__i, __result.second))
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__result.second = __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.first))
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__result.first = __first;
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if (!__less(__i, __result.second))
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__result.second = __i;
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} else {
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if (__less(__i, __result.first))
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__result.first = __i;
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if (!__less(__first, __result.second))
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__result.second = __first;
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}
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}
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return __result;
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}
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template <class _ForwardIterator, class _Compare>
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_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_ForwardIterator, _ForwardIterator>
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minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) {
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static_assert(
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__has_forward_iterator_category<_ForwardIterator>::value, "std::minmax_element requires a ForwardIterator");
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static_assert(
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__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value, "The comparator has to be callable");
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auto __proj = __identity();
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return std::__minmax_element_impl(__first, __last, __comp, __proj);
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}
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template <class _ForwardIterator>
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_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_ForwardIterator, _ForwardIterator>
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minmax_element(_ForwardIterator __first, _ForwardIterator __last) {
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return std::minmax_element(__first, __last, __less<>());
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}
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
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