| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H |
| #define _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H |
| |
| #include <__algorithm/iterator_operations.h> |
| #include <__algorithm/unwrap_iter.h> |
| #include <__algorithm/unwrap_range.h> |
| #include <__config> |
| #include <__iterator/iterator_traits.h> |
| #include <__memory/pointer_traits.h> |
| #include <__string/constexpr_c_functions.h> |
| #include <__type_traits/enable_if.h> |
| #include <__type_traits/is_always_bitcastable.h> |
| #include <__type_traits/is_constant_evaluated.h> |
| #include <__type_traits/is_constructible.h> |
| #include <__type_traits/is_trivially_assignable.h> |
| #include <__type_traits/is_trivially_copyable.h> |
| #include <__type_traits/is_volatile.h> |
| #include <__utility/move.h> |
| #include <__utility/pair.h> |
| #include <cstddef> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| // Type traits. |
| |
| template <class _From, class _To> |
| struct __can_lower_copy_assignment_to_memmove { |
| static const bool value = |
| // If the types are always bitcastable, it's valid to do a bitwise copy between them. |
| __is_always_bitcastable<_From, _To>::value && |
| // Reject conversions that wouldn't be performed by the regular built-in assignment (e.g. between arrays). |
| is_trivially_assignable<_To&, const _From&>::value && |
| // `memmove` doesn't accept `volatile` pointers, make sure the optimization SFINAEs away in that case. |
| !is_volatile<_From>::value && !is_volatile<_To>::value; |
| }; |
| |
| template <class _From, class _To> |
| struct __can_lower_move_assignment_to_memmove { |
| static const bool value = |
| __is_always_bitcastable<_From, _To>::value && is_trivially_assignable<_To&, _From&&>::value && |
| !is_volatile<_From>::value && !is_volatile<_To>::value; |
| }; |
| |
| // `memmove` algorithms implementation. |
| |
| template <class _In, class _Out> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*> |
| __copy_trivial_impl(_In* __first, _In* __last, _Out* __result) { |
| const size_t __n = static_cast<size_t>(__last - __first); |
| |
| std::__constexpr_memmove(__result, __first, __element_count(__n)); |
| |
| return std::make_pair(__last, __result + __n); |
| } |
| |
| template <class _In, class _Out> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*> |
| __copy_backward_trivial_impl(_In* __first, _In* __last, _Out* __result) { |
| const size_t __n = static_cast<size_t>(__last - __first); |
| __result -= __n; |
| |
| std::__constexpr_memmove(__result, __first, __element_count(__n)); |
| |
| return std::make_pair(__last, __result); |
| } |
| |
| // Iterator unwrapping and dispatching to the correct overload. |
| |
| template <class _InIter, class _OutIter> |
| struct __can_rewrap |
| : integral_constant<bool, is_copy_constructible<_InIter>::value && is_copy_constructible<_OutIter>::value> {}; |
| |
| template <class _Algorithm, |
| class _InIter, |
| class _Sent, |
| class _OutIter, |
| __enable_if_t<__can_rewrap<_InIter, _OutIter>::value, int> = 0> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter> |
| __copy_move_unwrap_iters(_InIter __first, _Sent __last, _OutIter __out_first) { |
| auto __range = std::__unwrap_range(__first, std::move(__last)); |
| auto __result = _Algorithm()(std::move(__range.first), std::move(__range.second), std::__unwrap_iter(__out_first)); |
| return std::make_pair(std::__rewrap_range<_Sent>(std::move(__first), std::move(__result.first)), |
| std::__rewrap_iter(std::move(__out_first), std::move(__result.second))); |
| } |
| |
| template <class _Algorithm, |
| class _InIter, |
| class _Sent, |
| class _OutIter, |
| __enable_if_t<!__can_rewrap<_InIter, _OutIter>::value, int> = 0> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter> |
| __copy_move_unwrap_iters(_InIter __first, _Sent __last, _OutIter __out_first) { |
| return _Algorithm()(std::move(__first), std::move(__last), std::move(__out_first)); |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H |