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___UTILITY_SWAP_H
10 #define _LIBCPP___UTILITY_SWAP_H
11 
12 #include <__config>
13 #include <__utility/declval.h>
14 #include <__utility/move.h>
15 #include <cstddef>
16 #include <type_traits>
17 
18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19 #pragma GCC system_header
20 #endif
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 #ifndef _LIBCPP_CXX03_LANG
25 template <class _Tp>
26 using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
27 #else
28 template <class>
29 using __swap_result_t = void;
30 #endif
31 
32 template <class _Tp>
33 inline _LIBCPP_INLINE_VISIBILITY __swap_result_t<_Tp> _LIBCPP_CONSTEXPR_AFTER_CXX17 swap(_Tp& __x, _Tp& __y)
34     _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value&& is_nothrow_move_assignable<_Tp>::value) {
35   _Tp __t(_VSTD::move(__x));
36   __x = _VSTD::move(__y);
37   __y = _VSTD::move(__t);
38 }
39 
40 template <class _Tp, size_t _Np>
41 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 typename enable_if<__is_swappable<_Tp>::value>::type
42 swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value) {
43   for (size_t __i = 0; __i != _Np; ++__i) {
44     swap(__a[__i], __b[__i]);
45   }
46 }
47 
48 _LIBCPP_END_NAMESPACE_STD
49 
50 #endif // _LIBCPP___UTILITY_SWAP_H
51