1 files changed, 108 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__iterator/iter_swap.h b/contrib/llvm-project/libcxx/include/__iterator/iter_swap.h
new file mode 100644
index 000000000000..52c3f095e7fb
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__iterator/iter_swap.h
@@ -0,0 +1,108 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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___ITERATOR_ITER_SWAP_H
+#define _LIBCPP___ITERATOR_ITER_SWAP_H
+
+#include <__concepts/class_or_enum.h>
+#include <__concepts/swappable.h>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/readable_traits.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+// [iter.cust.swap]
+
+namespace ranges {
+namespace __iter_swap {
+template <class _I1, class _I2>
+void iter_swap(_I1, _I2) = delete;
+
+template <class _T1, class _T2>
+concept __unqualified_iter_swap =
+    (__class_or_enum<remove_cvref_t<_T1>> || __class_or_enum<remove_cvref_t<_T2>>)&&requires(_T1&& __x, _T2&& __y) {
+      // NOLINTNEXTLINE(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap
+      iter_swap(std::forward<_T1>(__x), std::forward<_T2>(__y));
+    };
+
+template <class _T1, class _T2>
+concept __readable_swappable =
+    indirectly_readable<_T1> && indirectly_readable<_T2> &&
+    swappable_with<iter_reference_t<_T1>, iter_reference_t<_T2>>;
+
+struct __fn {
+  // NOLINTBEGIN(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap
+  template <class _T1, class _T2>
+    requires __unqualified_iter_swap<_T1, _T2>
+  _LIBCPP_HIDE_FROM_ABI constexpr void operator()(_T1&& __x, _T2&& __y) const
+      noexcept(noexcept(iter_swap(std::forward<_T1>(__x), std::forward<_T2>(__y)))) {
+    (void)iter_swap(std::forward<_T1>(__x), std::forward<_T2>(__y));
+  }
+  // NOLINTEND(libcpp-robust-against-adl)
+
+  template <class _T1, class _T2>
+    requires(!__unqualified_iter_swap<_T1, _T2>) && __readable_swappable<_T1, _T2>
+  _LIBCPP_HIDE_FROM_ABI constexpr void operator()(_T1&& __x, _T2&& __y) const
+      noexcept(noexcept(ranges::swap(*std::forward<_T1>(__x), *std::forward<_T2>(__y)))) {
+    ranges::swap(*std::forward<_T1>(__x), *std::forward<_T2>(__y));
+  }
+
+  template <class _T1, class _T2>
+    requires(!__unqualified_iter_swap<_T1, _T2> &&   //
+             !__readable_swappable<_T1, _T2>) &&     //
+            indirectly_movable_storable<_T1, _T2> && //
+            indirectly_movable_storable<_T2, _T1>
+  _LIBCPP_HIDE_FROM_ABI constexpr void operator()(_T1&& __x, _T2&& __y) const
+      noexcept(noexcept(iter_value_t<_T2>(ranges::iter_move(__y))) && //
+               noexcept(*__y = ranges::iter_move(__x)) &&             //
+               noexcept(*std::forward<_T1>(__x) = std::declval<iter_value_t<_T2>>())) {
+    iter_value_t<_T2> __old(ranges::iter_move(__y));
+    *__y                    = ranges::iter_move(__x);
+    *std::forward<_T1>(__x) = std::move(__old);
+  }
+};
+} // namespace __iter_swap
+
+inline namespace __cpo {
+inline constexpr auto iter_swap = __iter_swap::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+template <class _I1, class _I2 = _I1>
+concept indirectly_swappable =
+    indirectly_readable<_I1> && indirectly_readable<_I2> && requires(const _I1 __i1, const _I2 __i2) {
+      ranges::iter_swap(__i1, __i1);
+      ranges::iter_swap(__i2, __i2);
+      ranges::iter_swap(__i1, __i2);
+      ranges::iter_swap(__i2, __i1);
+    };
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ITERATOR_ITER_SWAP_H