Algorithms for ranges_find_last, find_last_if, and find_last_if_not

Author: xevor11

libcxx/include/__algorithm/ranges_find_last_if.h

@@ -0,0 +1,81 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_H
+#define _LIBCPP___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/dangling.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <optional>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+namespace __find_last_if {
+
+struct __fn {
+  template <forward_iterator _Ip,
+            sentinel_for<_Ip> _Sp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<_Ip, _Proj>> _Pred>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
+  operator()(_Ip __first, _Sp __last, _Pred __pred, _Proj __proj = {}) const {
+    std::optional<_Ip> __found;
+    for (; __first != __last; ++__first) {
+      if (std::invoke(__pred, std::invoke(__proj, *__first))) {
+        __found = __first;
+      }
+    }
+    if (!__found)
+      return {__first, __first};
+    return {*__found, std::ranges::next(*__found, __last)};
+  }
+
+  template <forward_range _Rp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Rp>, _Proj>> _Pred>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
+  operator()(_Rp&& __r, _Pred __pred, _Proj __proj = {}) const {
+    return this->operator()(ranges::begin(__r), ranges::end(__r), std::ref(__pred), std::ref(__proj));
+  }
+};
+
+} // namespace __find_last_if
+
+inline namespace __cpo {
+inline constexpr auto find_last_if = __find_last_if::__fn{};
+} // namespace __cpo
+
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_RANGES_FIND_LAST_IF_H

libcxx/include/__algorithm/ranges_find_last_if_not.h

@@ -0,0 +1,81 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <__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/dangling.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <optional>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+namespace __find_last_if_not {
+
+struct __fn {
+  template <forward_iterator _Ip,
+            sentinel_for<_Ip> _Sp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<_Ip, _Proj>> _Pred>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
+  operator()(_Ip __first, _Sp __last, _Pred __pred, _Proj __proj = {}) const {
+    std::optional<_Ip> __found;
+    for (; __first != __last; ++__first) {
+      if (!std::invoke(__pred, std::invoke(__proj, *__first))) {
+        __found = __first;
+      }
+    }
+    if (!__found)
+      return {__first, __first};
+    return {*__found, std::ranges::next(*__found, __last)};
+  }
+
+  template <forward_range _Rp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Rp>, _Proj>> _Pred>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
+  operator()(_Rp&& __r, _Pred __pred, _Proj __proj = {}) const {
+    return this->operator()(ranges::begin(__r), ranges::end(__r), std::ref(__pred), std::ref(__proj));
+  }
+};
+
+} // namespace __find_last_if_not
+
+inline namespace __cpo {
+inline constexpr auto find_last_if_not = __find_last_if_not::__fn{};
+} // namespace __cpo
+
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_RANGES_FIND_LAST_IF_NOT_H