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 _LIBCPP_PUSH_MACROS 31 #include <__undef_macros> 32 33 #if _LIBCPP_STD_VER >= 20 34 35 _LIBCPP_BEGIN_NAMESPACE_STD 36 37 namespace ranges { 38 39 template <class _InIter1, class _InIter2, class _OutIter> 40 using merge_result = in_in_out_result<_InIter1, _InIter2, _OutIter>; 41 42 namespace __merge { 43 44 template < class _InIter1, 45 class _Sent1, 46 class _InIter2, 47 class _Sent2, 48 class _OutIter, 49 class _Comp, 50 class _Proj1, 51 class _Proj2> 52 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<__remove_cvref_t<_InIter1>, 53 __remove_cvref_t<_InIter2>, 54 __remove_cvref_t<_OutIter>> 55 __merge_impl(_InIter1&& __first1, 56 _Sent1&& __last1, 57 _InIter2&& __first2, 58 _Sent2&& __last2, 59 _OutIter&& __result, 60 _Comp&& __comp, 61 _Proj1&& __proj1, 62 _Proj2&& __proj2) { 63 for (; __first1 != __last1 && __first2 != __last2; ++__result) { 64 if (std::invoke(__comp, std::invoke(__proj2, *__first2), std::invoke(__proj1, *__first1))) { 65 *__result = *__first2; 66 ++__first2; 67 } else { 68 *__result = *__first1; 69 ++__first1; 70 } 71 } 72 auto __ret1 = ranges::copy(std::move(__first1), std::move(__last1), std::move(__result)); 73 auto __ret2 = ranges::copy(std::move(__first2), std::move(__last2), std::move(__ret1.out)); 74 return {std::move(__ret1.in), std::move(__ret2.in), std::move(__ret2.out)}; 75 } 76 77 struct __fn { 78 template <input_iterator _InIter1, 79 sentinel_for<_InIter1> _Sent1, 80 input_iterator _InIter2, 81 sentinel_for<_InIter2> _Sent2, 82 weakly_incrementable _OutIter, 83 class _Comp = less, 84 class _Proj1 = identity, 85 class _Proj2 = identity> 86 requires mergeable<_InIter1, _InIter2, _OutIter, _Comp, _Proj1, _Proj2> 87 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<_InIter1, _InIter2, _OutIter> operator()( 88 _InIter1 __first1, 89 _Sent1 __last1, 90 _InIter2 __first2, 91 _Sent2 __last2, 92 _OutIter __result, 93 _Comp __comp = {}, 94 _Proj1 __proj1 = {}, 95 _Proj2 __proj2 = {}) const { 96 return __merge::__merge_impl(__first1, __last1, __first2, __last2, __result, __comp, __proj1, __proj2); 97 } 98 99 template <input_range _Range1, 100 input_range _Range2, 101 weakly_incrementable _OutIter, 102 class _Comp = less, 103 class _Proj1 = identity, 104 class _Proj2 = identity> 105 requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _OutIter, _Comp, _Proj1, _Proj2> 106 _LIBCPP_HIDE_FROM_ABI constexpr merge_result<borrowed_iterator_t<_Range1>, borrowed_iterator_t<_Range2>, _OutIter> 107 operator()(_Range1&& __range1, 108 _Range2&& __range2, 109 _OutIter __result, 110 _Comp __comp = {}, 111 _Proj1 __proj1 = {}, 112 _Proj2 __proj2 = {}) const { 113 return __merge::__merge_impl( 114 ranges::begin(__range1), 115 ranges::end(__range1), 116 ranges::begin(__range2), 117 ranges::end(__range2), 118 __result, 119 __comp, 120 __proj1, 121 __proj2); 122 } 123 }; 124 125 } // namespace __merge 126 127 inline namespace __cpo { 128 inline constexpr auto merge = __merge::__fn{}; 129 } // namespace __cpo 130 } // namespace ranges 131 132 _LIBCPP_END_NAMESPACE_STD 133 134 #endif // _LIBCPP_STD_VER >= 20 135 136 _LIBCPP_POP_MACROS 137 138 #endif // _LIBCPP___ALGORITHM_RANGES_MERGE_H 139