1// -*- C++ -*-
 2//===----------------------------------------------------------------------===//
 3//
 4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 5// See https://llvm.org/LICENSE.txt for license information.
 6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 7//
 8//===----------------------------------------------------------------------===//
 9
10#ifndef _LIBCPP___ITERATOR_EMPTY_H
11#define _LIBCPP___ITERATOR_EMPTY_H
12
13#include <__config>
14#include <initializer_list>
15
16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17#  pragma GCC system_header
18#endif
19
20_LIBCPP_BEGIN_NAMESPACE_STD
21
22#if _LIBCPP_STD_VER >= 17
23
24template <class _Cont>
25[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto
26empty(const _Cont& __c) noexcept(noexcept(__c.empty())) -> decltype(__c.empty()) {
27  return __c.empty();
28}
29
30template <class _Tp, size_t _Sz>
31[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty(const _Tp (&)[_Sz]) noexcept {
32  return false;
33}
34
35template <class _Ep>
36[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty(initializer_list<_Ep> __il) noexcept {
37  return __il.size() == 0;
38}
39
40#endif // _LIBCPP_STD_VER >= 17
41
42_LIBCPP_END_NAMESPACE_STD
43
44#endif // _LIBCPP___ITERATOR_EMPTY_H