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.
100 lines
3.8 KiB
C++
100 lines
3.8 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_UNWRAP_RANGE_H
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#define _LIBCPP___ALGORITHM_UNWRAP_RANGE_H
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#include <__algorithm/unwrap_iter.h>
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#include <__concepts/constructible.h>
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#include <__config>
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#include <__iterator/concepts.h>
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#include <__iterator/next.h>
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#include <__utility/declval.h>
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#include <__utility/move.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_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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// __unwrap_range and __rewrap_range are used to unwrap ranges which may have different iterator and sentinel types.
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// __unwrap_iter and __rewrap_iter don't work for this, because they assume that the iterator and sentinel have
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// the same type. __unwrap_range tries to get two iterators and then forward to __unwrap_iter.
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#if _LIBCPP_STD_VER >= 20
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template <class _Iter, class _Sent>
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struct __unwrap_range_impl {
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_LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __sent)
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requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>
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{
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auto __last = ranges::next(__first, __sent);
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return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))};
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}
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_LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __last) {
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return pair{std::move(__first), std::move(__last)};
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}
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_LIBCPP_HIDE_FROM_ABI static constexpr auto
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__rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(std::move(__orig_iter))) __iter)
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requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>
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{
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return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
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}
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_LIBCPP_HIDE_FROM_ABI static constexpr auto __rewrap(const _Iter&, _Iter __iter)
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requires(!(random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>))
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{
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return __iter;
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}
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};
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template <class _Iter>
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struct __unwrap_range_impl<_Iter, _Iter> {
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_LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Iter __last) {
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return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))};
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}
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_LIBCPP_HIDE_FROM_ABI static constexpr auto
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__rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter) {
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return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
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}
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};
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template <class _Iter, class _Sent>
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_LIBCPP_HIDE_FROM_ABI constexpr auto __unwrap_range(_Iter __first, _Sent __last) {
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return __unwrap_range_impl<_Iter, _Sent>::__unwrap(std::move(__first), std::move(__last));
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}
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template < class _Sent, class _Iter, class _Unwrapped>
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_LIBCPP_HIDE_FROM_ABI constexpr _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) {
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return __unwrap_range_impl<_Iter, _Sent>::__rewrap(std::move(__orig_iter), std::move(__iter));
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}
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#else // _LIBCPP_STD_VER >= 20
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template <class _Iter, class _Unwrapped = decltype(std::__unwrap_iter(std::declval<_Iter>()))>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR pair<_Unwrapped, _Unwrapped> __unwrap_range(_Iter __first, _Iter __last) {
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return std::make_pair(std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last)));
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}
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template <class _Iter, class _Unwrapped>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) {
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return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
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}
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#endif // _LIBCPP_STD_VER >= 20
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___ALGORITHM_UNWRAP_RANGE_H
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