1//===----------------------------------------------------------------------===//
 2//
 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 4// See https://llvm.org/LICENSE.txt for license information.
 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 6//
 7//===----------------------------------------------------------------------===//
 8
 9#ifndef _LIBCPP___ALGORITHM_RANGES_CLAMP_H
10#define _LIBCPP___ALGORITHM_RANGES_CLAMP_H
11
12#include <__assert>
13#include <__config>
14#include <__functional/identity.h>
15#include <__functional/invoke.h>
16#include <__functional/ranges_operations.h>
17#include <__iterator/concepts.h>
18#include <__iterator/projected.h>
19#include <__utility/forward.h>
20
21#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22#  pragma GCC system_header
23#endif
24
25_LIBCPP_PUSH_MACROS
26#include <__undef_macros>
27
28#if _LIBCPP_STD_VER >= 20
29
30_LIBCPP_BEGIN_NAMESPACE_STD
31
32namespace ranges {
33struct __clamp {
34  template <class _Type,
35            class _Proj                                                      = identity,
36            indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less>
37  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr const _Type& operator()(
38      const _Type& __value, const _Type& __low, const _Type& __high, _Comp __comp = {}, _Proj __proj = {}) const {
39    _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(
40        !bool(std::invoke(__comp, std::invoke(__proj, __high), std::invoke(__proj, __low))),
41        "Bad bounds passed to std::ranges::clamp");
42
43    auto&& __projected = std::invoke(__proj, __value);
44    if (std::invoke(__comp, std::forward<decltype(__projected)>(__projected), std::invoke(__proj, __low)))
45      return __low;
46    else if (std::invoke(__comp, std::invoke(__proj, __high), std::forward<decltype(__projected)>(__projected)))
47      return __high;
48    else
49      return __value;
50  }
51};
52
53inline namespace __cpo {
54inline constexpr auto clamp = __clamp{};
55} // namespace __cpo
56} // namespace ranges
57
58_LIBCPP_END_NAMESPACE_STD
59
60#endif // _LIBCPP_STD_VER >= 20
61
62_LIBCPP_POP_MACROS
63
64#endif // _LIBCPP___ALGORITHM_RANGES_CLAMP_H