libcxx/include/__algorithm/ranges_lexicographical_compare.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_LEXICOGRAPHICAL_COMPARE_H
  10 #define _LIBCPP___ALGORITHM_RANGES_LEXICOGRAPHICAL_COMPARE_H
  11
  12 #include <__config>
  13 #include <__functional/identity.h>
  14 #include <__functional/invoke.h>
  15 #include <__functional/ranges_operations.h>
  16 #include <__iterator/concepts.h>
  17 #include <__iterator/projected.h>
  18 #include <__ranges/access.h>
  19 #include <__ranges/concepts.h>
  20 #include <__utility/move.h>
  21
  22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  23 #  pragma GCC system_header
  24 #endif
  25
  26 #if _LIBCPP_STD_VER >= 20
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 namespace ranges {
  31 namespace __lexicographical_compare {
  32 struct __fn {
  33   template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Proj1, class _Proj2, class _Comp>
  34   _LIBCPP_HIDE_FROM_ABI constexpr static bool __lexicographical_compare_impl(
  35       _Iter1 __first1,
  36       _Sent1 __last1,
  37       _Iter2 __first2,
  38       _Sent2 __last2,
  39       _Comp& __comp,
  40       _Proj1& __proj1,
  41       _Proj2& __proj2) {
  42     while (__first2 != __last2) {
  43       if (__first1 == __last1 || std::invoke(__comp, std::invoke(__proj1, *__first1), std::invoke(__proj2, *__first2)))
  44         return true;
  45       if (std::invoke(__comp, std::invoke(__proj2, *__first2), std::invoke(__proj1, *__first1)))
  46         return false;
  47       ++__first1;
  48       ++__first2;
  49     }
  50     return false;
  51   }
  52
  53   template <input_iterator _Iter1,
  54             sentinel_for<_Iter1> _Sent1,
  55             input_iterator _Iter2,
  56             sentinel_for<_Iter2> _Sent2,
  57             class _Proj1                                                                           = identity,
  58             class _Proj2                                                                           = identity,
  59             indirect_strict_weak_order<projected<_Iter1, _Proj1>, projected<_Iter2, _Proj2>> _Comp = ranges::less>
  60   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(
  61       _Iter1 __first1,
  62       _Sent1 __last1,
  63       _Iter2 __first2,
  64       _Sent2 __last2,
  65       _Comp __comp   = {},
  66       _Proj1 __proj1 = {},
  67       _Proj2 __proj2 = {}) const {
  68     return __lexicographical_compare_impl(
  69         std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __comp, __proj1, __proj2);
  70   }
  71
  72   template <input_range _Range1,
  73             input_range _Range2,
  74             class _Proj1 = identity,
  75             class _Proj2 = identity,
  76             indirect_strict_weak_order<projected<iterator_t<_Range1>, _Proj1>, projected<iterator_t<_Range2>, _Proj2>>
  77                 _Comp = ranges::less>
  78   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(
  79       _Range1&& __range1, _Range2&& __range2, _Comp __comp = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const {
  80     return __lexicographical_compare_impl(
  81         ranges::begin(__range1),
  82         ranges::end(__range1),
  83         ranges::begin(__range2),
  84         ranges::end(__range2),
  85         __comp,
  86         __proj1,
  87         __proj2);
  88   }
  89 };
  90 } // namespace __lexicographical_compare
  91
  92 inline namespace __cpo {
  93 inline constexpr auto lexicographical_compare = __lexicographical_compare::__fn{};
  94 } // namespace __cpo
  95 } // namespace ranges
  96
  97 _LIBCPP_END_NAMESPACE_STD
  98
  99 #endif // _LIBCPP_STD_VER >= 20
 100
 101 #endif // _LIBCPP___ALGORITHM_RANGES_LEXICOGRAPHICAL_COMPARE_H