1 files changed, 85 insertions, 0 deletions
diff --git a/libcxx/include/__algorithm/ranges_remove_if.h b/libcxx/include/__algorithm/ranges_remove_if.h
new file mode 100644
index 000000000000..d4e382e551c6
--- /dev/null
+++ b/libcxx/include/__algorithm/ranges_remove_if.h
@@ -0,0 +1,85 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_REMOVE_IF_H
+#define _LIBCPP___ALGORITHM_RANGES_REMOVE_IF_H
+#include <__config>
+
+#include <__algorithm/ranges_find_if.h>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/permutable.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
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+template <class _Iter, class _Sent, class _Proj, class _Pred>
+_LIBCPP_HIDE_FROM_ABI constexpr
+subrange<_Iter> __remove_if_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
+  auto __new_end = ranges::__find_if_impl(__first, __last, __pred, __proj);
+  if (__new_end == __last)
+    return {__new_end, __new_end};
+
+  _Iter __i = __new_end;
+  while (++__i != __last) {
+    if (!std::invoke(__pred, std::invoke(__proj, *__i))) {
+      *__new_end = ranges::iter_move(__i);
+      ++__new_end;
+    }
+  }
+  return {__new_end, __i};
+}
+
+namespace __remove_if {
+struct __fn {
+
+  template <permutable _Iter, sentinel_for<_Iter> _Sent,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  subrange<_Iter> operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {
+    return ranges::__remove_if_impl(std::move(__first), std::move(__last), __pred, __proj);
+  }
+
+  template <forward_range _Range,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
+    requires permutable<iterator_t<_Range>>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  borrowed_subrange_t<_Range> operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
+    return ranges::__remove_if_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
+  }
+
+};
+} // namespace __remove_if
+
+inline namespace __cpo {
+  inline constexpr auto remove_if = __remove_if::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#endif // _LIBCPP___ALGORITHM_RANGES_REMOVE_IF_H