libcxx/include/__algorithm/ranges_equal.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_EQUAL_H
  10 #define _LIBCPP___ALGORITHM_RANGES_EQUAL_H
  11
  12 #include <__algorithm/equal.h>
  13 #include <__algorithm/unwrap_range.h>
  14 #include <__config>
  15 #include <__functional/identity.h>
  16 #include <__functional/invoke.h>
  17 #include <__functional/ranges_operations.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 <__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 struct __equal {
  38   template <input_iterator _Iter1,
  39             sentinel_for<_Iter1> _Sent1,
  40             input_iterator _Iter2,
  41             sentinel_for<_Iter2> _Sent2,
  42             class _Pred  = ranges::equal_to,
  43             class _Proj1 = identity,
  44             class _Proj2 = identity>
  45     requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
  46   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(
  47       _Iter1 __first1,
  48       _Sent1 __last1,
  49       _Iter2 __first2,
  50       _Sent2 __last2,
  51       _Pred __pred   = {},
  52       _Proj1 __proj1 = {},
  53       _Proj2 __proj2 = {}) const {
  54     if constexpr (sized_sentinel_for<_Sent1, _Iter1> && sized_sentinel_for<_Sent2, _Iter2>) {
  55       if (__last1 - __first1 != __last2 - __first2)
  56         return false;
  57     }
  58     auto __unwrapped1 = std::__unwrap_range(std::move(__first1), std::move(__last1));
  59     auto __unwrapped2 = std::__unwrap_range(std::move(__first2), std::move(__last2));
  60     return std::__equal_impl(
  61         std::move(__unwrapped1.first),
  62         std::move(__unwrapped1.second),
  63         std::move(__unwrapped2.first),
  64         std::move(__unwrapped2.second),
  65         __pred,
  66         __proj1,
  67         __proj2);
  68   }
  69
  70   template <input_range _Range1,
  71             input_range _Range2,
  72             class _Pred  = ranges::equal_to,
  73             class _Proj1 = identity,
  74             class _Proj2 = identity>
  75     requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
  76   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(
  77       _Range1&& __range1, _Range2&& __range2, _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
  78     if constexpr (sized_range<_Range1> && sized_range<_Range2>) {
  79       if (ranges::distance(__range1) != ranges::distance(__range2))
  80         return false;
  81     }
  82     auto __unwrapped1 = std::__unwrap_range(ranges::begin(__range1), ranges::end(__range1));
  83     auto __unwrapped2 = std::__unwrap_range(ranges::begin(__range2), ranges::end(__range2));
  84     return std::__equal_impl(
  85         std::move(__unwrapped1.first),
  86         std::move(__unwrapped1.second),
  87         std::move(__unwrapped2.first),
  88         std::move(__unwrapped2.second),
  89         __pred,
  90         __proj1,
  91         __proj2);
  92     return false;
  93   }
  94 };
  95
  96 inline namespace __cpo {
  97 inline constexpr auto equal = __equal{};
  98 } // namespace __cpo
  99 } // namespace ranges
 100
 101 _LIBCPP_END_NAMESPACE_STD
 102
 103 #endif // _LIBCPP_STD_VER >= 20
 104
 105 _LIBCPP_POP_MACROS
 106
 107 #endif // _LIBCPP___ALGORITHM_RANGES_EQUAL_H