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___ALGORITHM_RANGES_MERGE_H 10 #define _LIBCPP___ALGORITHM_RANGES_MERGE_H 11 12 #include <__algorithm/in_in_out_result.h> 13 #include <__algorithm/ranges_copy.h> 14 #include <__config> 15 #include <__functional/identity.h> 16 #include <__functional/invoke.h> 17 #include <__functional/ranges_operations.h> 18 #include <__iterator/concepts.h> 19 #include <__iterator/mergeable.h> 20 #include <__ranges/access.h> 21 #include <__ranges/concepts.h> 22 #include <__ranges/dangling.h> 23 #include <__type_traits/remove_cvref.h> 24 #include <__utility/move.h> 25 26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 27 # pragma GCC system_header 28 #endif 29 30 #if _LIBCPP_STD_VER >= 20 31 32 _LIBCPP_BEGIN_NAMESPACE_STD 33 34 namespace ranges { 35 36 template <class _InIter1, class _InIter2, class _OutIter> 37 using merge_result = in_in_out_result<_InIter1, _InIter2, _OutIter>; 38 39 namespace __merge { 40 41 template < class _InIter1, 42 class _Sent1, 43 class _InIter2, 44 class _Sent2, 45 class _OutIter, 46 class _Comp, 47 class _Proj1, 48 class _Proj2> 49 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<__remove_cvref_t<_InIter1>, 50 __remove_cvref_t<_InIter2>, 51 __remove_cvref_t<_OutIter>> 52 __merge_impl(_InIter1&& __first1, 53 _Sent1&& __last1, 54 _InIter2&& __first2, 55 _Sent2&& __last2, 56 _OutIter&& __result, 57 _Comp&& __comp, 58 _Proj1&& __proj1, 59 _Proj2&& __proj2) { 60 for (; __first1 != __last1 && __first2 != __last2; ++__result) { 61 if (std::invoke(__comp, std::invoke(__proj2, *__first2), std::invoke(__proj1, *__first1))) { 62 *__result = *__first2; 63 ++__first2; 64 } else { 65 *__result = *__first1; 66 ++__first1; 67 } 68 } 69 auto __ret1 = ranges::copy(std::move(__first1), std::move(__last1), std::move(__result)); 70 auto __ret2 = ranges::copy(std::move(__first2), std::move(__last2), std::move(__ret1.out)); 71 return {std::move(__ret1.in), std::move(__ret2.in), std::move(__ret2.out)}; 72 } 73 74 struct __fn { 75 template <input_iterator _InIter1, 76 sentinel_for<_InIter1> _Sent1, 77 input_iterator _InIter2, 78 sentinel_for<_InIter2> _Sent2, 79 weakly_incrementable _OutIter, 80 class _Comp = less, 81 class _Proj1 = identity, 82 class _Proj2 = identity> 83 requires mergeable<_InIter1, _InIter2, _OutIter, _Comp, _Proj1, _Proj2> 84 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<_InIter1, _InIter2, _OutIter> operator()( 85 _InIter1 __first1, 86 _Sent1 __last1, 87 _InIter2 __first2, 88 _Sent2 __last2, 89 _OutIter __result, 90 _Comp __comp = {}, 91 _Proj1 __proj1 = {}, 92 _Proj2 __proj2 = {}) const { 93 return __merge::__merge_impl(__first1, __last1, __first2, __last2, __result, __comp, __proj1, __proj2); 94 } 95 96 template <input_range _Range1, 97 input_range _Range2, 98 weakly_incrementable _OutIter, 99 class _Comp = less, 100 class _Proj1 = identity, 101 class _Proj2 = identity> 102 requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _OutIter, _Comp, _Proj1, _Proj2> 103 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<borrowed_iterator_t<_Range1>, borrowed_iterator_t<_Range2>, _OutIter> 104 operator()(_Range1&& __range1, 105 _Range2&& __range2, 106 _OutIter __result, 107 _Comp __comp = {}, 108 _Proj1 __proj1 = {}, 109 _Proj2 __proj2 = {}) const { 110 return __merge::__merge_impl( 111 ranges::begin(__range1), 112 ranges::end(__range1), 113 ranges::begin(__range2), 114 ranges::end(__range2), 115 __result, 116 __comp, 117 __proj1, 118 __proj2); 119 } 120 }; 121 122 } // namespace __merge 123 124 inline namespace __cpo { 125 inline constexpr auto merge = __merge::__fn{}; 126 } // namespace __cpo 127 } // namespace ranges 128 129 _LIBCPP_END_NAMESPACE_STD 130 131 #endif // _LIBCPP_STD_VER >= 20 132 133 #endif // _LIBCPP___ALGORITHM_RANGES_MERGE_H 134