1bdd1243dSDimitry Andric //===----------------------------------------------------------------------===// 2bdd1243dSDimitry Andric // 3bdd1243dSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4bdd1243dSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5bdd1243dSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6bdd1243dSDimitry Andric // 7bdd1243dSDimitry Andric //===----------------------------------------------------------------------===// 8bdd1243dSDimitry Andric 9bdd1243dSDimitry Andric #ifndef _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H 10bdd1243dSDimitry Andric #define _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H 11bdd1243dSDimitry Andric 12bdd1243dSDimitry Andric #include <__algorithm/iterator_operations.h> 13bdd1243dSDimitry Andric #include <__algorithm/unwrap_iter.h> 14bdd1243dSDimitry Andric #include <__algorithm/unwrap_range.h> 15bdd1243dSDimitry Andric #include <__config> 16bdd1243dSDimitry Andric #include <__iterator/iterator_traits.h> 17bdd1243dSDimitry Andric #include <__memory/pointer_traits.h> 1806c3fb27SDimitry Andric #include <__string/constexpr_c_functions.h> 19bdd1243dSDimitry Andric #include <__type_traits/enable_if.h> 20bdd1243dSDimitry Andric #include <__type_traits/is_always_bitcastable.h> 21bdd1243dSDimitry Andric #include <__type_traits/is_constant_evaluated.h> 22*0fca6ea1SDimitry Andric #include <__type_traits/is_constructible.h> 23bdd1243dSDimitry Andric #include <__type_traits/is_trivially_assignable.h> 24bdd1243dSDimitry Andric #include <__type_traits/is_volatile.h> 25bdd1243dSDimitry Andric #include <__utility/move.h> 26bdd1243dSDimitry Andric #include <__utility/pair.h> 27bdd1243dSDimitry Andric #include <cstddef> 28bdd1243dSDimitry Andric 29bdd1243dSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 30bdd1243dSDimitry Andric # pragma GCC system_header 31bdd1243dSDimitry Andric #endif 32bdd1243dSDimitry Andric 33b3edf446SDimitry Andric _LIBCPP_PUSH_MACROS 34b3edf446SDimitry Andric #include <__undef_macros> 35b3edf446SDimitry Andric 36bdd1243dSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 37bdd1243dSDimitry Andric 38bdd1243dSDimitry Andric // Type traits. 39bdd1243dSDimitry Andric 40bdd1243dSDimitry Andric template <class _From, class _To> 41bdd1243dSDimitry Andric struct __can_lower_copy_assignment_to_memmove { 42bdd1243dSDimitry Andric static const bool value = 43bdd1243dSDimitry Andric // If the types are always bitcastable, it's valid to do a bitwise copy between them. 44bdd1243dSDimitry Andric __is_always_bitcastable<_From, _To>::value && 45bdd1243dSDimitry Andric // Reject conversions that wouldn't be performed by the regular built-in assignment (e.g. between arrays). 46bdd1243dSDimitry Andric is_trivially_assignable<_To&, const _From&>::value && 47bdd1243dSDimitry Andric // `memmove` doesn't accept `volatile` pointers, make sure the optimization SFINAEs away in that case. 48cb14a3feSDimitry Andric !is_volatile<_From>::value && !is_volatile<_To>::value; 49bdd1243dSDimitry Andric }; 50bdd1243dSDimitry Andric 51bdd1243dSDimitry Andric template <class _From, class _To> 52bdd1243dSDimitry Andric struct __can_lower_move_assignment_to_memmove { 53bdd1243dSDimitry Andric static const bool value = 54cb14a3feSDimitry Andric __is_always_bitcastable<_From, _To>::value && is_trivially_assignable<_To&, _From&&>::value && 55cb14a3feSDimitry Andric !is_volatile<_From>::value && !is_volatile<_To>::value; 56bdd1243dSDimitry Andric }; 57bdd1243dSDimitry Andric 58bdd1243dSDimitry Andric // `memmove` algorithms implementation. 59bdd1243dSDimitry Andric 60bdd1243dSDimitry Andric template <class _In, class _Out> 61bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*> 62bdd1243dSDimitry Andric __copy_trivial_impl(_In* __first, _In* __last, _Out* __result) { 63bdd1243dSDimitry Andric const size_t __n = static_cast<size_t>(__last - __first); 6406c3fb27SDimitry Andric 6506c3fb27SDimitry Andric std::__constexpr_memmove(__result, __first, __element_count(__n)); 66bdd1243dSDimitry Andric 67bdd1243dSDimitry Andric return std::make_pair(__last, __result + __n); 68bdd1243dSDimitry Andric } 69bdd1243dSDimitry Andric 70bdd1243dSDimitry Andric template <class _In, class _Out> 71bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*> 72bdd1243dSDimitry Andric __copy_backward_trivial_impl(_In* __first, _In* __last, _Out* __result) { 73bdd1243dSDimitry Andric const size_t __n = static_cast<size_t>(__last - __first); 74bdd1243dSDimitry Andric __result -= __n; 75bdd1243dSDimitry Andric 7606c3fb27SDimitry Andric std::__constexpr_memmove(__result, __first, __element_count(__n)); 77bdd1243dSDimitry Andric 78bdd1243dSDimitry Andric return std::make_pair(__last, __result); 79bdd1243dSDimitry Andric } 80bdd1243dSDimitry Andric 81bdd1243dSDimitry Andric // Iterator unwrapping and dispatching to the correct overload. 82bdd1243dSDimitry Andric 83*0fca6ea1SDimitry Andric template <class _InIter, class _OutIter> 84*0fca6ea1SDimitry Andric struct __can_rewrap 85*0fca6ea1SDimitry Andric : integral_constant<bool, is_copy_constructible<_InIter>::value && is_copy_constructible<_OutIter>::value> {}; 86bdd1243dSDimitry Andric 87bdd1243dSDimitry Andric template <class _Algorithm, 88bdd1243dSDimitry Andric class _InIter, 89bdd1243dSDimitry Andric class _Sent, 90bdd1243dSDimitry Andric class _OutIter, 91*0fca6ea1SDimitry Andric __enable_if_t<__can_rewrap<_InIter, _OutIter>::value, int> = 0> 92bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter> 93*0fca6ea1SDimitry Andric __copy_move_unwrap_iters(_InIter __first, _Sent __last, _OutIter __out_first) { 94bdd1243dSDimitry Andric auto __range = std::__unwrap_range(__first, std::move(__last)); 95bdd1243dSDimitry Andric auto __result = _Algorithm()(std::move(__range.first), std::move(__range.second), std::__unwrap_iter(__out_first)); 96bdd1243dSDimitry Andric return std::make_pair(std::__rewrap_range<_Sent>(std::move(__first), std::move(__result.first)), 97bdd1243dSDimitry Andric std::__rewrap_iter(std::move(__out_first), std::move(__result.second))); 98bdd1243dSDimitry Andric } 99bdd1243dSDimitry Andric 100bdd1243dSDimitry Andric template <class _Algorithm, 101bdd1243dSDimitry Andric class _InIter, 102bdd1243dSDimitry Andric class _Sent, 103bdd1243dSDimitry Andric class _OutIter, 104*0fca6ea1SDimitry Andric __enable_if_t<!__can_rewrap<_InIter, _OutIter>::value, int> = 0> 105bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter> 106*0fca6ea1SDimitry Andric __copy_move_unwrap_iters(_InIter __first, _Sent __last, _OutIter __out_first) { 107bdd1243dSDimitry Andric return _Algorithm()(std::move(__first), std::move(__last), std::move(__out_first)); 108bdd1243dSDimitry Andric } 109bdd1243dSDimitry Andric 110bdd1243dSDimitry Andric _LIBCPP_END_NAMESPACE_STD 111bdd1243dSDimitry Andric 112b3edf446SDimitry Andric _LIBCPP_POP_MACROS 113b3edf446SDimitry Andric 114bdd1243dSDimitry Andric #endif // _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H 115