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