swap.h 1.8 KB

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  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. #ifndef _LIBCPP___UTILITY_SWAP_H
  9. #define _LIBCPP___UTILITY_SWAP_H
  10. #include <__config>
  11. #include <__type_traits/is_move_assignable.h>
  12. #include <__type_traits/is_move_constructible.h>
  13. #include <__type_traits/is_nothrow_move_assignable.h>
  14. #include <__type_traits/is_nothrow_move_constructible.h>
  15. #include <__type_traits/is_swappable.h>
  16. #include <__utility/declval.h>
  17. #include <__utility/move.h>
  18. #include <cstddef>
  19. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  20. # pragma GCC system_header
  21. #endif
  22. _LIBCPP_BEGIN_NAMESPACE_STD
  23. #ifndef _LIBCPP_CXX03_LANG
  24. template <class _Tp>
  25. using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
  26. #else
  27. template <class>
  28. using __swap_result_t = void;
  29. #endif
  30. template <class _Tp>
  31. inline _LIBCPP_INLINE_VISIBILITY __swap_result_t<_Tp> _LIBCPP_CONSTEXPR_SINCE_CXX20 swap(_Tp& __x, _Tp& __y)
  32. _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value&& is_nothrow_move_assignable<_Tp>::value) {
  33. _Tp __t(_VSTD::move(__x));
  34. __x = _VSTD::move(__y);
  35. __y = _VSTD::move(__t);
  36. }
  37. template <class _Tp, size_t _Np>
  38. inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 typename enable_if<__is_swappable<_Tp>::value>::type
  39. swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value) {
  40. for (size_t __i = 0; __i != _Np; ++__i) {
  41. swap(__a[__i], __b[__i]);
  42. }
  43. }
  44. _LIBCPP_END_NAMESPACE_STD
  45. #endif // _LIBCPP___UTILITY_SWAP_H