libcxx/include/__algorithm/ranges_search.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_SEARCH_H
  10 #define _LIBCPP___ALGORITHM_RANGES_SEARCH_H
  11
  12 #include <__algorithm/iterator_operations.h>
  13 #include <__algorithm/search.h>
  14 #include <__config>
  15 #include <__functional/identity.h>
  16 #include <__functional/ranges_operations.h>
  17 #include <__iterator/advance.h>
  18 #include <__iterator/concepts.h>
  19 #include <__iterator/distance.h>
  20 #include <__iterator/indirectly_comparable.h>
  21 #include <__ranges/access.h>
  22 #include <__ranges/concepts.h>
  23 #include <__ranges/size.h>
  24 #include <__ranges/subrange.h>
  25 #include <__utility/pair.h>
  26
  27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  28 #  pragma GCC system_header
  29 #endif
  30
  31 #if _LIBCPP_STD_VER >= 20
  32
  33 _LIBCPP_BEGIN_NAMESPACE_STD
  34
  35 namespace ranges {
  36 struct __search {
  37   template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
  38   _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_impl(
  39       _Iter1 __first1,
  40       _Sent1 __last1,
  41       _Iter2 __first2,
  42       _Sent2 __last2,
  43       _Pred& __pred,
  44       _Proj1& __proj1,
  45       _Proj2& __proj2) {
  46     if constexpr (sized_sentinel_for<_Sent2, _Iter2>) {
  47       auto __size2 = ranges::distance(__first2, __last2);
  48       if (__size2 == 0)
  49         return {__first1, __first1};
  50
  51       if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
  52         auto __size1 = ranges::distance(__first1, __last1);
  53         if (__size1 < __size2) {
  54           ranges::advance(__first1, __last1);
  55           return {__first1, __first1};
  56         }
  57
  58         if constexpr (random_access_iterator<_Iter1> && random_access_iterator<_Iter2>) {
  59           auto __ret = std::__search_random_access_impl<_RangeAlgPolicy>(
  60               __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
  61           return {__ret.first, __ret.second};
  62         }
  63       }
  64     }
  65
  66     auto __ret =
  67         std::__search_forward_impl<_RangeAlgPolicy>(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
  68     return {__ret.first, __ret.second};
  69   }
  70
  71   template <forward_iterator _Iter1,
  72             sentinel_for<_Iter1> _Sent1,
  73             forward_iterator _Iter2,
  74             sentinel_for<_Iter2> _Sent2,
  75             class _Pred  = ranges::equal_to,
  76             class _Proj1 = identity,
  77             class _Proj2 = identity>
  78     requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
  79   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter1> operator()(
  80       _Iter1 __first1,
  81       _Sent1 __last1,
  82       _Iter2 __first2,
  83       _Sent2 __last2,
  84       _Pred __pred   = {},
  85       _Proj1 __proj1 = {},
  86       _Proj2 __proj2 = {}) const {
  87     return __ranges_search_impl(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
  88   }
  89
  90   template <forward_range _Range1,
  91             forward_range _Range2,
  92             class _Pred  = ranges::equal_to,
  93             class _Proj1 = identity,
  94             class _Proj2 = identity>
  95     requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
  96   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range1> operator()(
  97       _Range1&& __range1, _Range2&& __range2, _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
  98     auto __first1 = ranges::begin(__range1);
  99     if constexpr (sized_range<_Range2>) {
 100       auto __size2 = ranges::size(__range2);
 101       if (__size2 == 0)
 102         return {__first1, __first1};
 103       if constexpr (sized_range<_Range1>) {
 104         auto __size1 = ranges::size(__range1);
 105         if (__size1 < __size2) {
 106           ranges::advance(__first1, ranges::end(__range1));
 107           return {__first1, __first1};
 108         }
 109       }
 110     }
 111
 112     return __ranges_search_impl(
 113         ranges::begin(__range1),
 114         ranges::end(__range1),
 115         ranges::begin(__range2),
 116         ranges::end(__range2),
 117         __pred,
 118         __proj1,
 119         __proj2);
 120   }
 121 };
 122
 123 inline namespace __cpo {
 124 inline constexpr auto search = __search{};
 125 } // namespace __cpo
 126 } // namespace ranges
 127
 128 _LIBCPP_END_NAMESPACE_STD
 129
 130 #endif // _LIBCPP_STD_VER >= 20
 131
 132 #endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_H