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
102