__cxx03/__algorithm/ranges_search.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_SEARCH_H
0010 #define _LIBCPP___CXX03___ALGORITHM_RANGES_SEARCH_H
0011
0012 #include <__cxx03/__algorithm/iterator_operations.h>
0013 #include <__cxx03/__algorithm/search.h>
0014 #include <__cxx03/__config>
0015 #include <__cxx03/__functional/identity.h>
0016 #include <__cxx03/__functional/ranges_operations.h>
0017 #include <__cxx03/__iterator/advance.h>
0018 #include <__cxx03/__iterator/concepts.h>
0019 #include <__cxx03/__iterator/distance.h>
0020 #include <__cxx03/__iterator/indirectly_comparable.h>
0021 #include <__cxx03/__ranges/access.h>
0022 #include <__cxx03/__ranges/concepts.h>
0023 #include <__cxx03/__ranges/size.h>
0024 #include <__cxx03/__ranges/subrange.h>
0025 #include <__cxx03/__utility/pair.h>
0026
0027 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0028 #  pragma GCC system_header
0029 #endif
0030
0031 #if _LIBCPP_STD_VER >= 20
0032
0033 _LIBCPP_BEGIN_NAMESPACE_STD
0034
0035 namespace ranges {
0036 namespace __search {
0037 struct __fn {
0038   template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
0039   _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_impl(
0040       _Iter1 __first1,
0041       _Sent1 __last1,
0042       _Iter2 __first2,
0043       _Sent2 __last2,
0044       _Pred& __pred,
0045       _Proj1& __proj1,
0046       _Proj2& __proj2) {
0047     if constexpr (sized_sentinel_for<_Sent2, _Iter2>) {
0048       auto __size2 = ranges::distance(__first2, __last2);
0049       if (__size2 == 0)
0050         return {__first1, __first1};
0051
0052       if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
0053         auto __size1 = ranges::distance(__first1, __last1);
0054         if (__size1 < __size2) {
0055           ranges::advance(__first1, __last1);
0056           return {__first1, __first1};
0057         }
0058
0059         if constexpr (random_access_iterator<_Iter1> && random_access_iterator<_Iter2>) {
0060           auto __ret = std::__search_random_access_impl<_RangeAlgPolicy>(
0061               __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
0062           return {__ret.first, __ret.second};
0063         }
0064       }
0065     }
0066
0067     auto __ret =
0068         std::__search_forward_impl<_RangeAlgPolicy>(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
0069     return {__ret.first, __ret.second};
0070   }
0071
0072   template <forward_iterator _Iter1,
0073             sentinel_for<_Iter1> _Sent1,
0074             forward_iterator _Iter2,
0075             sentinel_for<_Iter2> _Sent2,
0076             class _Pred  = ranges::equal_to,
0077             class _Proj1 = identity,
0078             class _Proj2 = identity>
0079     requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
0080   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter1> operator()(
0081       _Iter1 __first1,
0082       _Sent1 __last1,
0083       _Iter2 __first2,
0084       _Sent2 __last2,
0085       _Pred __pred   = {},
0086       _Proj1 __proj1 = {},
0087       _Proj2 __proj2 = {}) const {
0088     return __ranges_search_impl(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
0089   }
0090
0091   template <forward_range _Range1,
0092             forward_range _Range2,
0093             class _Pred  = ranges::equal_to,
0094             class _Proj1 = identity,
0095             class _Proj2 = identity>
0096     requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
0097   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range1> operator()(
0098       _Range1&& __range1, _Range2&& __range2, _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
0099     auto __first1 = ranges::begin(__range1);
0100     if constexpr (sized_range<_Range2>) {
0101       auto __size2 = ranges::size(__range2);
0102       if (__size2 == 0)
0103         return {__first1, __first1};
0104       if constexpr (sized_range<_Range1>) {
0105         auto __size1 = ranges::size(__range1);
0106         if (__size1 < __size2) {
0107           ranges::advance(__first1, ranges::end(__range1));
0108           return {__first1, __first1};
0109         }
0110       }
0111     }
0112
0113     return __ranges_search_impl(
0114         ranges::begin(__range1),
0115         ranges::end(__range1),
0116         ranges::begin(__range2),
0117         ranges::end(__range2),
0118         __pred,
0119         __proj1,
0120         __proj2);
0121   }
0122 };
0123 } // namespace __search
0124
0125 inline namespace __cpo {
0126 inline constexpr auto search = __search::__fn{};
0127 } // namespace __cpo
0128 } // namespace ranges
0129
0130 _LIBCPP_END_NAMESPACE_STD
0131
0132 #endif // _LIBCPP_STD_VER >= 20
0133
0134 #endif // _LIBCPP___CXX03___ALGORITHM_RANGES_SEARCH_H