1 files changed, 97 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__algorithm/unwrap_range.h b/contrib/llvm-project/libcxx/include/__algorithm/unwrap_range.h
new file mode 100644
index 000000000000..745906a96e15
--- /dev/null
+++ b/contrib/llvm-project/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 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+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