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 {
33namespace __clamp {
34struct __fn {
35 template <class _Type,
36 class _Proj = identity,
37 indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less>
38 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr const _Type& operator()(
39 const _Type& __value, const _Type& __low, const _Type& __high, _Comp __comp = {}, _Proj __proj = {}) const {
40 _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(
41 !bool(std::invoke(__comp, std::invoke(__proj, __high), std::invoke(__proj, __low))),
42 "Bad bounds passed to std::ranges::clamp");
43
44 auto&& __projected = std::invoke(__proj, __value);
45 if (std::invoke(__comp, std::forward<decltype(__projected)>(__projected), std::invoke(__proj, __low)))
46 return __low;
47 else if (std::invoke(__comp, std::invoke(__proj, __high), std::forward<decltype(__projected)>(__projected)))
48 return __high;
49 else
50 return __value;
51 }
52};
53} // namespace __clamp
54
55inline namespace __cpo {
56inline constexpr auto clamp = __clamp::__fn{};
57} // namespace __cpo
58} // namespace ranges
59
60_LIBCPP_END_NAMESPACE_STD
61
62#endif // _LIBCPP_STD_VER >= 20
63
64_LIBCPP_POP_MACROS
65
66#endif // _LIBCPP___ALGORITHM_RANGES_CLAMP_H
67