xref: /freebsd/contrib/llvm-project/libcxx/include/__iterator/empty.h (revision ebacd8013fe5f7fdf9f6a5b286f6680dd2891036)
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 > 14
24 
25 template <class _Cont>
26 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
27 constexpr auto empty(const _Cont& __c)
28 _NOEXCEPT_(noexcept(__c.empty()))
29 -> decltype        (__c.empty())
30 { return            __c.empty(); }
31 
32 template <class _Tp, size_t _Sz>
33 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
34 constexpr bool empty(const _Tp (&)[_Sz]) noexcept { return false; }
35 
36 template <class _Ep>
37 _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
38 constexpr bool empty(initializer_list<_Ep> __il) noexcept { return __il.size() == 0; }
39 
40 #endif // _LIBCPP_STD_VER > 14
41 
42 _LIBCPP_END_NAMESPACE_STD
43 
44 #endif // _LIBCPP___ITERATOR_EMPTY_H
45