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 
25 template <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 
31 template <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 
36 template <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