__cxx03/__algorithm/ranges_transform.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___CXX03___ALGORITHM_RANGES_TRANSFORM_H
0010 #define _LIBCPP___CXX03___ALGORITHM_RANGES_TRANSFORM_H
0011
0012 #include <__cxx03/__algorithm/in_in_out_result.h>
0013 #include <__cxx03/__algorithm/in_out_result.h>
0014 #include <__cxx03/__concepts/constructible.h>
0015 #include <__cxx03/__config>
0016 #include <__cxx03/__functional/identity.h>
0017 #include <__cxx03/__functional/invoke.h>
0018 #include <__cxx03/__iterator/concepts.h>
0019 #include <__cxx03/__iterator/projected.h>
0020 #include <__cxx03/__ranges/access.h>
0021 #include <__cxx03/__ranges/concepts.h>
0022 #include <__cxx03/__ranges/dangling.h>
0023 #include <__cxx03/__utility/move.h>
0024
0025 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0026 #  pragma GCC system_header
0027 #endif
0028
0029 _LIBCPP_PUSH_MACROS
0030 #include <__cxx03/__undef_macros>
0031
0032 #if _LIBCPP_STD_VER >= 20
0033
0034 _LIBCPP_BEGIN_NAMESPACE_STD
0035
0036 namespace ranges {
0037
0038 template <class _Ip, class _Op>
0039 using unary_transform_result = in_out_result<_Ip, _Op>;
0040
0041 template <class _I1, class _I2, class _O1>
0042 using binary_transform_result = in_in_out_result<_I1, _I2, _O1>;
0043
0044 namespace __transform {
0045 struct __fn {
0046 private:
0047   template <class _InIter, class _Sent, class _OutIter, class _Func, class _Proj>
0048   _LIBCPP_HIDE_FROM_ABI static constexpr unary_transform_result<_InIter, _OutIter>
0049   __unary(_InIter __first, _Sent __last, _OutIter __result, _Func& __operation, _Proj& __projection) {
0050     while (__first != __last) {
0051       *__result = std::invoke(__operation, std::invoke(__projection, *__first));
0052       ++__first;
0053       ++__result;
0054     }
0055
0056     return {std::move(__first), std::move(__result)};
0057   }
0058
0059   template <class _InIter1,
0060             class _Sent1,
0061             class _InIter2,
0062             class _Sent2,
0063             class _OutIter,
0064             class _Func,
0065             class _Proj1,
0066             class _Proj2>
0067   _LIBCPP_HIDE_FROM_ABI static constexpr binary_transform_result<_InIter1, _InIter2, _OutIter>
0068   __binary(_InIter1 __first1,
0069            _Sent1 __last1,
0070            _InIter2 __first2,
0071            _Sent2 __last2,
0072            _OutIter __result,
0073            _Func& __binary_operation,
0074            _Proj1& __projection1,
0075            _Proj2& __projection2) {
0076     while (__first1 != __last1 && __first2 != __last2) {
0077       *__result =
0078           std::invoke(__binary_operation, std::invoke(__projection1, *__first1), std::invoke(__projection2, *__first2));
0079       ++__first1;
0080       ++__first2;
0081       ++__result;
0082     }
0083     return {std::move(__first1), std::move(__first2), std::move(__result)};
0084   }
0085
0086 public:
0087   template <input_iterator _InIter,
0088             sentinel_for<_InIter> _Sent,
0089             weakly_incrementable _OutIter,
0090             copy_constructible _Func,
0091             class _Proj = identity>
0092     requires indirectly_writable<_OutIter, indirect_result_t<_Func&, projected<_InIter, _Proj>>>
0093   _LIBCPP_HIDE_FROM_ABI constexpr unary_transform_result<_InIter, _OutIter>
0094   operator()(_InIter __first, _Sent __last, _OutIter __result, _Func __operation, _Proj __proj = {}) const {
0095     return __unary(std::move(__first), std::move(__last), std::move(__result), __operation, __proj);
0096   }
0097
0098   template <input_range _Range, weakly_incrementable _OutIter, copy_constructible _Func, class _Proj = identity>
0099     requires indirectly_writable<_OutIter, indirect_result_t<_Func, projected<iterator_t<_Range>, _Proj>>>
0100   _LIBCPP_HIDE_FROM_ABI constexpr unary_transform_result<borrowed_iterator_t<_Range>, _OutIter>
0101   operator()(_Range&& __range, _OutIter __result, _Func __operation, _Proj __projection = {}) const {
0102     return __unary(ranges::begin(__range), ranges::end(__range), std::move(__result), __operation, __projection);
0103   }
0104
0105   template <input_iterator _InIter1,
0106             sentinel_for<_InIter1> _Sent1,
0107             input_iterator _InIter2,
0108             sentinel_for<_InIter2> _Sent2,
0109             weakly_incrementable _OutIter,
0110             copy_constructible _Func,
0111             class _Proj1 = identity,
0112             class _Proj2 = identity>
0113     requires indirectly_writable<_OutIter,
0114                                  indirect_result_t<_Func&, projected<_InIter1, _Proj1>, projected<_InIter2, _Proj2>>>
0115   _LIBCPP_HIDE_FROM_ABI constexpr binary_transform_result<_InIter1, _InIter2, _OutIter> operator()(
0116       _InIter1 __first1,
0117       _Sent1 __last1,
0118       _InIter2 __first2,
0119       _Sent2 __last2,
0120       _OutIter __result,
0121       _Func __binary_operation,
0122       _Proj1 __projection1 = {},
0123       _Proj2 __projection2 = {}) const {
0124     return __binary(
0125         std::move(__first1),
0126         std::move(__last1),
0127         std::move(__first2),
0128         std::move(__last2),
0129         std::move(__result),
0130         __binary_operation,
0131         __projection1,
0132         __projection2);
0133   }
0134
0135   template <input_range _Range1,
0136             input_range _Range2,
0137             weakly_incrementable _OutIter,
0138             copy_constructible _Func,
0139             class _Proj1 = identity,
0140             class _Proj2 = identity>
0141     requires indirectly_writable<
0142         _OutIter,
0143         indirect_result_t<_Func&, projected<iterator_t<_Range1>, _Proj1>, projected<iterator_t<_Range2>, _Proj2>>>
0144   _LIBCPP_HIDE_FROM_ABI constexpr binary_transform_result<borrowed_iterator_t<_Range1>,
0145                                                           borrowed_iterator_t<_Range2>,
0146                                                           _OutIter>
0147   operator()(_Range1&& __range1,
0148              _Range2&& __range2,
0149              _OutIter __result,
0150              _Func __binary_operation,
0151              _Proj1 __projection1 = {},
0152              _Proj2 __projection2 = {}) const {
0153     return __binary(
0154         ranges::begin(__range1),
0155         ranges::end(__range1),
0156         ranges::begin(__range2),
0157         ranges::end(__range2),
0158         std::move(__result),
0159         __binary_operation,
0160         __projection1,
0161         __projection2);
0162   }
0163 };
0164 } // namespace __transform
0165
0166 inline namespace __cpo {
0167 inline constexpr auto transform = __transform::__fn{};
0168 } // namespace __cpo
0169 } // namespace ranges
0170
0171 _LIBCPP_END_NAMESPACE_STD
0172
0173 #endif // _LIBCPP_STD_VER >= 20
0174
0175 _LIBCPP_POP_MACROS
0176
0177 #endif // _LIBCPP___CXX03___ALGORITHM_RANGES_TRANSFORM_H