libcxx/include/__cxx03/__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 <__cxx03/__algorithm/iterator_operations.h>
  13 #include <__cxx03/__algorithm/search.h>
  14 #include <__cxx03/__config>
  15 #include <__cxx03/__functional/identity.h>
  16 #include <__cxx03/__functional/ranges_operations.h>
  17 #include <__cxx03/__iterator/advance.h>
  18 #include <__cxx03/__iterator/concepts.h>
  19 #include <__cxx03/__iterator/distance.h>
  20 #include <__cxx03/__iterator/indirectly_comparable.h>
  21 #include <__cxx03/__ranges/access.h>
  22 #include <__cxx03/__ranges/concepts.h>
  23 #include <__cxx03/__ranges/size.h>
  24 #include <__cxx03/__ranges/subrange.h>
  25 #include <__cxx03/__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 namespace __search {
  37 struct __fn {
  38   template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
  39   _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_impl(
  40       _Iter1 __first1,
  41       _Sent1 __last1,
  42       _Iter2 __first2,
  43       _Sent2 __last2,
  44       _Pred& __pred,
  45       _Proj1& __proj1,
  46       _Proj2& __proj2) {
  47     if constexpr (sized_sentinel_for<_Sent2, _Iter2>) {
  48       auto __size2 = ranges::distance(__first2, __last2);
  49       if (__size2 == 0)
  50         return {__first1, __first1};
  51
  52       if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
  53         auto __size1 = ranges::distance(__first1, __last1);
  54         if (__size1 < __size2) {
  55           ranges::advance(__first1, __last1);
  56           return {__first1, __first1};
  57         }
  58
  59         if constexpr (random_access_iterator<_Iter1> && random_access_iterator<_Iter2>) {
  60           auto __ret = std::__search_random_access_impl<_RangeAlgPolicy>(
  61               __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
  62           return {__ret.first, __ret.second};
  63         }
  64       }
  65     }
  66
  67     auto __ret =
  68         std::__search_forward_impl<_RangeAlgPolicy>(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
  69     return {__ret.first, __ret.second};
  70   }
  71
  72   template <forward_iterator _Iter1,
  73             sentinel_for<_Iter1> _Sent1,
  74             forward_iterator _Iter2,
  75             sentinel_for<_Iter2> _Sent2,
  76             class _Pred  = ranges::equal_to,
  77             class _Proj1 = identity,
  78             class _Proj2 = identity>
  79     requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
  80   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter1> operator()(
  81       _Iter1 __first1,
  82       _Sent1 __last1,
  83       _Iter2 __first2,
  84       _Sent2 __last2,
  85       _Pred __pred   = {},
  86       _Proj1 __proj1 = {},
  87       _Proj2 __proj2 = {}) const {
  88     return __ranges_search_impl(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
  89   }
  90
  91   template <forward_range _Range1,
  92             forward_range _Range2,
  93             class _Pred  = ranges::equal_to,
  94             class _Proj1 = identity,
  95             class _Proj2 = identity>
  96     requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
  97   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range1> operator()(
  98       _Range1&& __range1, _Range2&& __range2, _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
  99     auto __first1 = ranges::begin(__range1);
 100     if constexpr (sized_range<_Range2>) {
 101       auto __size2 = ranges::size(__range2);
 102       if (__size2 == 0)
 103         return {__first1, __first1};
 104       if constexpr (sized_range<_Range1>) {
 105         auto __size1 = ranges::size(__range1);
 106         if (__size1 < __size2) {
 107           ranges::advance(__first1, ranges::end(__range1));
 108           return {__first1, __first1};
 109         }
 110       }
 111     }
 112
 113     return __ranges_search_impl(
 114         ranges::begin(__range1),
 115         ranges::end(__range1),
 116         ranges::begin(__range2),
 117         ranges::end(__range2),
 118         __pred,
 119         __proj1,
 120         __proj2);
 121   }
 122 };
 123 } // namespace __search
 124
 125 inline namespace __cpo {
 126 inline constexpr auto search = __search::__fn{};
 127 } // namespace __cpo
 128 } // namespace ranges
 129
 130 _LIBCPP_END_NAMESPACE_STD
 131
 132 #endif // _LIBCPP_STD_VER >= 20
 133
 134 #endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_H