[libcxx-commits] [libcxx] [libc++][ranges] P1223R5: `find_last` (PR #99312)

[nicole mazzuca via libcxx-commits]

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@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_RANGES_FIND_LAST_IF_NOT_H
+#define _LIBCPP___ALGORITHM_RANGES_FIND_LAST_IF_NOT_H
+
+#include <__algorithm/ranges_find_last_if.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/subrange.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 23
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __find_last_if_not {
+struct __fn {
+  template <forward_iterator _Iter,
+            sentinel_for<_Iter> _Sent,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr static subrange<_Iter>
+  operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) {
+    auto __pred2 = [&__pred](auto&& __e) -> bool { return !std::invoke(__pred, std::forward<decltype(__e)>(__e)); };
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strega-nil wrote:

`not_fn` does an extra copy of the function object. Could be worked around via `not_fn(ref(__pred))`. The reason I did this wsa that this is what `ranges::find_last_if_not` does.

https://github.com/llvm/llvm-project/pull/99312