diff options
author | Dimitry Andric <dim@FreeBSD.org> | 2023-02-11 12:38:04 +0000 |
---|---|---|
committer | Dimitry Andric <dim@FreeBSD.org> | 2023-02-11 12:38:11 +0000 |
commit | e3b557809604d036af6e00c60f012c2025b59a5e (patch) | |
tree | 8a11ba2269a3b669601e2fd41145b174008f4da8 /libcxx/include/__algorithm/unwrap_range.h | |
parent | 08e8dd7b9db7bb4a9de26d44c1cbfd24e869c014 (diff) | |
download | src-e3b557809604d036af6e00c60f012c2025b59a5e.tar.gz src-e3b557809604d036af6e00c60f012c2025b59a5e.zip |
Diffstat (limited to 'libcxx/include/__algorithm/unwrap_range.h')
-rw-r--r-- | libcxx/include/__algorithm/unwrap_range.h | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/libcxx/include/__algorithm/unwrap_range.h b/libcxx/include/__algorithm/unwrap_range.h new file mode 100644 index 000000000000..2c5d23e69f10 --- /dev/null +++ b/libcxx/include/__algorithm/unwrap_range.h @@ -0,0 +1,97 @@ +//===----------------------------------------------------------------------===// +// +// 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_UNWRAP_RANGE_H +#define _LIBCPP___ALGORITHM_UNWRAP_RANGE_H + +#include <__algorithm/unwrap_iter.h> +#include <__concepts/constructible.h> +#include <__config> +#include <__iterator/concepts.h> +#include <__iterator/next.h> +#include <__utility/declval.h> +#include <__utility/move.h> +#include <__utility/pair.h> + +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +# pragma GCC system_header +#endif + +_LIBCPP_BEGIN_NAMESPACE_STD + +// __unwrap_range and __rewrap_range are used to unwrap ranges which may have different iterator and sentinel types. +// __unwrap_iter and __rewrap_iter don't work for this, because they assume that the iterator and sentinel have +// the same type. __unwrap_range tries to get two iterators and then forward to __unwrap_iter. + +#if _LIBCPP_STD_VER > 17 +template <class _Iter, class _Sent> +struct __unwrap_range_impl { + _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __sent) + requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter> + { + auto __last = ranges::next(__first, __sent); + return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))}; + } + + _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __last) { + return pair{std::move(__first), std::move(__last)}; + } + + _LIBCPP_HIDE_FROM_ABI static constexpr auto + __rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter) + requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter> + { + return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter)); + } + + _LIBCPP_HIDE_FROM_ABI static constexpr auto __rewrap(const _Iter&, _Iter __iter) + requires (!(random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>)) + { + return __iter; + } +}; + +template <class _Iter> +struct __unwrap_range_impl<_Iter, _Iter> { + _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Iter __last) { + return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))}; + } + + _LIBCPP_HIDE_FROM_ABI static constexpr auto + __rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter) { + return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter)); + } +}; + +template <class _Iter, class _Sent> +_LIBCPP_HIDE_FROM_ABI constexpr auto __unwrap_range(_Iter __first, _Sent __last) { + return __unwrap_range_impl<_Iter, _Sent>::__unwrap(std::move(__first), std::move(__last)); +} + +template < + class _Sent, + class _Iter, + class _Unwrapped = decltype(std::__unwrap_range(std::declval<_Iter>(), std::declval<_Sent>()))> +_LIBCPP_HIDE_FROM_ABI constexpr _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) { + return __unwrap_range_impl<_Iter, _Sent>::__rewrap(std::move(__orig_iter), std::move(__iter)); +} +#else // _LIBCPP_STD_VER > 17 +template <class _Iter, class _Unwrapped = decltype(std::__unwrap_iter(std::declval<_Iter>()))> +_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR pair<_Unwrapped, _Unwrapped> __unwrap_range(_Iter __first, _Iter __last) { + return std::make_pair(std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))); +} + +template <class _Iter, class _Unwrapped = decltype(std::__unwrap_iter(std::declval<_Iter>()))> +_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) { + return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter)); +} +#endif // _LIBCPP_STD_VER > 17 + +_LIBCPP_END_NAMESPACE_STD + +#endif // _LIBCPP___ALGORITHM_UNWRAP_RANGE_H |