libcxx/include/__algorithm/ranges_transform.h

   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_TRANSFORM_H
  10 #define _LIBCPP___ALGORITHM_RANGES_TRANSFORM_H
  11
  12 #include <__algorithm/in_in_out_result.h>
  13 #include <__algorithm/in_out_result.h>
  14 #include <__concepts/constructible.h>
  15 #include <__config>
  16 #include <__functional/identity.h>
  17 #include <__functional/invoke.h>
  18 #include <__iterator/concepts.h>
  19 #include <__iterator/projected.h>
  20 #include <__ranges/access.h>
  21 #include <__ranges/concepts.h>
  22 #include <__ranges/dangling.h>
  23 #include <__utility/move.h>
  24
  25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  26 #  pragma GCC system_header
  27 #endif
  28
  29 _LIBCPP_PUSH_MACROS
  30 #include <__undef_macros>
  31
  32 #if _LIBCPP_STD_VER >= 20
  33
  34 _LIBCPP_BEGIN_NAMESPACE_STD
  35
  36 namespace ranges {
  37
  38 template <class _Ip, class _Op>
  39 using unary_transform_result = in_out_result<_Ip, _Op>;
  40
  41 template <class _I1, class _I2, class _O1>
  42 using binary_transform_result = in_in_out_result<_I1, _I2, _O1>;
  43
  44 struct __transform {
  45 private:
  46   template <class _InIter, class _Sent, class _OutIter, class _Func, class _Proj>
  47   _LIBCPP_HIDE_FROM_ABI static constexpr unary_transform_result<_InIter, _OutIter>
  48   __unary(_InIter __first, _Sent __last, _OutIter __result, _Func& __operation, _Proj& __projection) {
  49     while (__first != __last) {
  50       *__result = std::invoke(__operation, std::invoke(__projection, *__first));
  51       ++__first;
  52       ++__result;
  53     }
  54
  55     return {std::move(__first), std::move(__result)};
  56   }
  57
  58   template <class _InIter1,
  59             class _Sent1,
  60             class _InIter2,
  61             class _Sent2,
  62             class _OutIter,
  63             class _Func,
  64             class _Proj1,
  65             class _Proj2>
  66   _LIBCPP_HIDE_FROM_ABI static constexpr binary_transform_result<_InIter1, _InIter2, _OutIter>
  67   __binary(_InIter1 __first1,
  68            _Sent1 __last1,
  69            _InIter2 __first2,
  70            _Sent2 __last2,
  71            _OutIter __result,
  72            _Func& __binary_operation,
  73            _Proj1& __projection1,
  74            _Proj2& __projection2) {
  75     while (__first1 != __last1 && __first2 != __last2) {
  76       *__result =
  77           std::invoke(__binary_operation, std::invoke(__projection1, *__first1), std::invoke(__projection2, *__first2));
  78       ++__first1;
  79       ++__first2;
  80       ++__result;
  81     }
  82     return {std::move(__first1), std::move(__first2), std::move(__result)};
  83   }
  84
  85 public:
  86   template <input_iterator _InIter,
  87             sentinel_for<_InIter> _Sent,
  88             weakly_incrementable _OutIter,
  89             copy_constructible _Func,
  90             class _Proj = identity>
  91     requires indirectly_writable<_OutIter, indirect_result_t<_Func&, projected<_InIter, _Proj>>>
  92   _LIBCPP_HIDE_FROM_ABI constexpr unary_transform_result<_InIter, _OutIter>
  93   operator()(_InIter __first, _Sent __last, _OutIter __result, _Func __operation, _Proj __proj = {}) const {
  94     return __unary(std::move(__first), std::move(__last), std::move(__result), __operation, __proj);
  95   }
  96
  97   template <input_range _Range, weakly_incrementable _OutIter, copy_constructible _Func, class _Proj = identity>
  98     requires indirectly_writable<_OutIter, indirect_result_t<_Func, projected<iterator_t<_Range>, _Proj>>>
  99   _LIBCPP_HIDE_FROM_ABI constexpr unary_transform_result<borrowed_iterator_t<_Range>, _OutIter>
 100   operator()(_Range&& __range, _OutIter __result, _Func __operation, _Proj __projection = {}) const {
 101     return __unary(ranges::begin(__range), ranges::end(__range), std::move(__result), __operation, __projection);
 102   }
 103
 104   template <input_iterator _InIter1,
 105             sentinel_for<_InIter1> _Sent1,
 106             input_iterator _InIter2,
 107             sentinel_for<_InIter2> _Sent2,
 108             weakly_incrementable _OutIter,
 109             copy_constructible _Func,
 110             class _Proj1 = identity,
 111             class _Proj2 = identity>
 112     requires indirectly_writable<_OutIter,
 113                                  indirect_result_t<_Func&, projected<_InIter1, _Proj1>, projected<_InIter2, _Proj2>>>
 114   _LIBCPP_HIDE_FROM_ABI constexpr binary_transform_result<_InIter1, _InIter2, _OutIter> operator()(
 115       _InIter1 __first1,
 116       _Sent1 __last1,
 117       _InIter2 __first2,
 118       _Sent2 __last2,
 119       _OutIter __result,
 120       _Func __binary_operation,
 121       _Proj1 __projection1 = {},
 122       _Proj2 __projection2 = {}) const {
 123     return __binary(
 124         std::move(__first1),
 125         std::move(__last1),
 126         std::move(__first2),
 127         std::move(__last2),
 128         std::move(__result),
 129         __binary_operation,
 130         __projection1,
 131         __projection2);
 132   }
 133
 134   template <input_range _Range1,
 135             input_range _Range2,
 136             weakly_incrementable _OutIter,
 137             copy_constructible _Func,
 138             class _Proj1 = identity,
 139             class _Proj2 = identity>
 140     requires indirectly_writable<
 141         _OutIter,
 142         indirect_result_t<_Func&, projected<iterator_t<_Range1>, _Proj1>, projected<iterator_t<_Range2>, _Proj2>>>
 143   _LIBCPP_HIDE_FROM_ABI constexpr binary_transform_result<borrowed_iterator_t<_Range1>,
 144                                                           borrowed_iterator_t<_Range2>,
 145                                                           _OutIter>
 146   operator()(_Range1&& __range1,
 147              _Range2&& __range2,
 148              _OutIter __result,
 149              _Func __binary_operation,
 150              _Proj1 __projection1 = {},
 151              _Proj2 __projection2 = {}) const {
 152     return __binary(
 153         ranges::begin(__range1),
 154         ranges::end(__range1),
 155         ranges::begin(__range2),
 156         ranges::end(__range2),
 157         std::move(__result),
 158         __binary_operation,
 159         __projection1,
 160         __projection2);
 161   }
 162 };
 163
 164 inline namespace __cpo {
 165 inline constexpr auto transform = __transform{};
 166 } // namespace __cpo
 167 } // namespace ranges
 168
 169 _LIBCPP_END_NAMESPACE_STD
 170
 171 #endif // _LIBCPP_STD_VER >= 20
 172
 173 _LIBCPP_POP_MACROS
 174
 175 #endif // _LIBCPP___ALGORITHM_RANGES_TRANSFORM_H