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 <cstddef>
15#include <initializer_list>
16
17#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18#  pragma GCC system_header
19#endif
20
21_LIBCPP_BEGIN_NAMESPACE_STD
22
23#if _LIBCPP_STD_VER >= 17
24
25template <class _Cont>
26_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI constexpr auto empty(const _Cont& __c)
27    _NOEXCEPT_(noexcept(__c.empty())) -> decltype(__c.empty()) {
28  return __c.empty();
29}
30
31template <class _Tp, size_t _Sz>
32_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI constexpr bool empty(const _Tp (&)[_Sz]) noexcept {
33  return false;
34}
35
36template <class _Ep>
37_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI constexpr bool empty(initializer_list<_Ep> __il) noexcept {
38  return __il.size() == 0;
39}
40
41#endif // _LIBCPP_STD_VER >= 17
42
43_LIBCPP_END_NAMESPACE_STD
44
45#endif // _LIBCPP___ITERATOR_EMPTY_H
46