1 files changed, 73 insertions, 0 deletions
diff --git a/libcxx/include/__algorithm/ranges_min_element.h b/libcxx/include/__algorithm/ranges_min_element.h
new file mode 100644
index 000000000000..ae82dceb9ad8
--- /dev/null
+++ b/libcxx/include/__algorithm/ranges_min_element.h
@@ -0,0 +1,73 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_MIN_ELEMENT_H
+#define _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_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>
+
+#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 _Ip, class _Sp, class _Proj, class _Comp>
+_LIBCPP_HIDE_FROM_ABI static constexpr
+_Ip __min_element_impl(_Ip __first, _Sp __last, _Comp& __comp, _Proj& __proj) {
+  if (__first == __last)
+    return __first;
+
+  _Ip __i = __first;
+  while (++__i != __last)
+    if (std::invoke(__comp, std::invoke(__proj, *__i), std::invoke(__proj, *__first)))
+      __first = __i;
+  return __first;
+}
+
+namespace __min_element {
+struct __fn {
+  template <forward_iterator _Ip, sentinel_for<_Ip> _Sp, class _Proj = identity,
+            indirect_strict_weak_order<projected<_Ip, _Proj>> _Comp = ranges::less>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  _Ip operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const {
+    return ranges::__min_element_impl(__first, __last, __comp, __proj);
+  }
+
+  template <forward_range _Rp, class _Proj = identity,
+            indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  borrowed_iterator_t<_Rp> operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
+    return ranges::__min_element_impl(ranges::begin(__r), ranges::end(__r), __comp, __proj);
+  }
+};
+} // namespace __min_element
+
+inline namespace __cpo {
+  inline constexpr auto min_element = __min_element::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#endif // _LIBCPP___ALGORITHM_RANGES_MIN_ELEMENT_H