v1/__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___ALGORITHM_RANGES_TRANSFORM_H
0010 #define _LIBCPP___ALGORITHM_RANGES_TRANSFORM_H
0011
0012 #include <__algorithm/in_in_out_result.h>
0013 #include <__algorithm/in_out_result.h>
0014 #include <__concepts/constructible.h>
0015 #include <__config>
0016 #include <__functional/identity.h>
0017 #include <__functional/invoke.h>
0018 #include <__iterator/concepts.h>
0019 #include <__iterator/projected.h>
0020 #include <__ranges/access.h>
0021 #include <__ranges/concepts.h>
0022 #include <__ranges/dangling.h>
0023 #include <__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 <__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 struct __transform {
0045 private:
0046   template <class _InIter, class _Sent, class _OutIter, class _Func, class _Proj>
0047   _LIBCPP_HIDE_FROM_ABI static constexpr unary_transform_result<_InIter, _OutIter>
0048   __unary(_InIter __first, _Sent __last, _OutIter __result, _Func& __operation, _Proj& __projection) {
0049     while (__first != __last) {
0050       *__result = std::invoke(__operation, std::invoke(__projection, *__first));
0051       ++__first;
0052       ++__result;
0053     }
0054
0055     return {std::move(__first), std::move(__result)};
0056   }
0057
0058   template <class _InIter1,
0059             class _Sent1,
0060             class _InIter2,
0061             class _Sent2,
0062             class _OutIter,
0063             class _Func,
0064             class _Proj1,
0065             class _Proj2>
0066   _LIBCPP_HIDE_FROM_ABI static constexpr binary_transform_result<_InIter1, _InIter2, _OutIter>
0067   __binary(_InIter1 __first1,
0068            _Sent1 __last1,
0069            _InIter2 __first2,
0070            _Sent2 __last2,
0071            _OutIter __result,
0072            _Func& __binary_operation,
0073            _Proj1& __projection1,
0074            _Proj2& __projection2) {
0075     while (__first1 != __last1 && __first2 != __last2) {
0076       *__result =
0077           std::invoke(__binary_operation, std::invoke(__projection1, *__first1), std::invoke(__projection2, *__first2));
0078       ++__first1;
0079       ++__first2;
0080       ++__result;
0081     }
0082     return {std::move(__first1), std::move(__first2), std::move(__result)};
0083   }
0084
0085 public:
0086   template <input_iterator _InIter,
0087             sentinel_for<_InIter> _Sent,
0088             weakly_incrementable _OutIter,
0089             copy_constructible _Func,
0090             class _Proj = identity>
0091     requires indirectly_writable<_OutIter, indirect_result_t<_Func&, projected<_InIter, _Proj>>>
0092   _LIBCPP_HIDE_FROM_ABI constexpr unary_transform_result<_InIter, _OutIter>
0093   operator()(_InIter __first, _Sent __last, _OutIter __result, _Func __operation, _Proj __proj = {}) const {
0094     return __unary(std::move(__first), std::move(__last), std::move(__result), __operation, __proj);
0095   }
0096
0097   template <input_range _Range, weakly_incrementable _OutIter, copy_constructible _Func, class _Proj = identity>
0098     requires indirectly_writable<_OutIter, indirect_result_t<_Func, projected<iterator_t<_Range>, _Proj>>>
0099   _LIBCPP_HIDE_FROM_ABI constexpr unary_transform_result<borrowed_iterator_t<_Range>, _OutIter>
0100   operator()(_Range&& __range, _OutIter __result, _Func __operation, _Proj __projection = {}) const {
0101     return __unary(ranges::begin(__range), ranges::end(__range), std::move(__result), __operation, __projection);
0102   }
0103
0104   template <input_iterator _InIter1,
0105             sentinel_for<_InIter1> _Sent1,
0106             input_iterator _InIter2,
0107             sentinel_for<_InIter2> _Sent2,
0108             weakly_incrementable _OutIter,
0109             copy_constructible _Func,
0110             class _Proj1 = identity,
0111             class _Proj2 = identity>
0112     requires indirectly_writable<_OutIter,
0113                                  indirect_result_t<_Func&, projected<_InIter1, _Proj1>, projected<_InIter2, _Proj2>>>
0114   _LIBCPP_HIDE_FROM_ABI constexpr binary_transform_result<_InIter1, _InIter2, _OutIter> operator()(
0115       _InIter1 __first1,
0116       _Sent1 __last1,
0117       _InIter2 __first2,
0118       _Sent2 __last2,
0119       _OutIter __result,
0120       _Func __binary_operation,
0121       _Proj1 __projection1 = {},
0122       _Proj2 __projection2 = {}) const {
0123     return __binary(
0124         std::move(__first1),
0125         std::move(__last1),
0126         std::move(__first2),
0127         std::move(__last2),
0128         std::move(__result),
0129         __binary_operation,
0130         __projection1,
0131         __projection2);
0132   }
0133
0134   template <input_range _Range1,
0135             input_range _Range2,
0136             weakly_incrementable _OutIter,
0137             copy_constructible _Func,
0138             class _Proj1 = identity,
0139             class _Proj2 = identity>
0140     requires indirectly_writable<
0141         _OutIter,
0142         indirect_result_t<_Func&, projected<iterator_t<_Range1>, _Proj1>, projected<iterator_t<_Range2>, _Proj2>>>
0143   _LIBCPP_HIDE_FROM_ABI constexpr binary_transform_result<borrowed_iterator_t<_Range1>,
0144                                                           borrowed_iterator_t<_Range2>,
0145                                                           _OutIter>
0146   operator()(_Range1&& __range1,
0147              _Range2&& __range2,
0148              _OutIter __result,
0149              _Func __binary_operation,
0150              _Proj1 __projection1 = {},
0151              _Proj2 __projection2 = {}) const {
0152     return __binary(
0153         ranges::begin(__range1),
0154         ranges::end(__range1),
0155         ranges::begin(__range2),
0156         ranges::end(__range2),
0157         std::move(__result),
0158         __binary_operation,
0159         __projection1,
0160         __projection2);
0161   }
0162 };
0163
0164 inline namespace __cpo {
0165 inline constexpr auto transform = __transform{};
0166 } // namespace __cpo
0167 } // namespace ranges
0168
0169 _LIBCPP_END_NAMESPACE_STD
0170
0171 #endif // _LIBCPP_STD_VER >= 20
0172
0173 _LIBCPP_POP_MACROS
0174
0175 #endif // _LIBCPP___ALGORITHM_RANGES_TRANSFORM_H