xref: /llvm-project/libcxx/test/std/containers/views/mdspan/layout_right/comparison.pass.cpp (revision e99c4906e44ae3f921fa05356909d006cda8d954)
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 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
10 
11 // <mdspan>
12 
13 // template<class OtherExtents>
14 //   friend constexpr bool operator==(const mapping& x, const mapping<OtherExtents>& y) noexcept;
15 //                                      `
16 // Constraints: extents_type::rank() == OtherExtents::rank() is true.
17 
18 #include <cassert>
19 #include <cstddef>
20 #include <mdspan>
21 #include <span> // dynamic_extent
22 
23 #include "test_macros.h"
24 
25 template <class To, class From>
26 constexpr void test_comparison(bool equal, To dest_exts, From src_exts) {
27   std::layout_right::mapping<To> dest(dest_exts);
28   std::layout_right::mapping<From> src(src_exts);
29   ASSERT_NOEXCEPT(dest == src);
30   assert((dest == src) == equal);
31   assert((dest != src) == !equal);
32 }
33 
34 struct X {
35   constexpr bool does_not_match() { return true; }
36 };
37 
38 constexpr X compare_layout_mappings(...) { return {}; }
39 
40 template <class E1, class E2>
41 constexpr auto compare_layout_mappings(E1 e1, E2 e2)
42     -> decltype(std::layout_right::mapping<E1>(e1) == std::layout_right::mapping<E2>(e2)) {
43   return true;
44 }
45 
46 template <class T1, class T2>
47 constexpr void test_comparison_different_rank() {
48   constexpr size_t D = std::dynamic_extent;
49 
50   // sanity check same rank
51   static_assert(compare_layout_mappings(std::extents<T1, D>(5), std::extents<T2, D>(5)));
52   static_assert(compare_layout_mappings(std::extents<T1, 5>(), std::extents<T2, D>(5)));
53   static_assert(compare_layout_mappings(std::extents<T1, D>(5), std::extents<T2, 5>()));
54   static_assert(compare_layout_mappings(std::extents<T1, 5>(), std::extents<T2, 5>()));
55 
56   // not equality comparable when rank is not the same
57   static_assert(compare_layout_mappings(std::extents<T1>(), std::extents<T2, D>(1)).does_not_match());
58   static_assert(compare_layout_mappings(std::extents<T1>(), std::extents<T2, 1>()).does_not_match());
59 
60   static_assert(compare_layout_mappings(std::extents<T1, D>(1), std::extents<T2>()).does_not_match());
61   static_assert(compare_layout_mappings(std::extents<T1, 1>(), std::extents<T2>()).does_not_match());
62 
63   static_assert(compare_layout_mappings(std::extents<T1, D>(5), std::extents<T2, D, D>(5, 5)).does_not_match());
64   static_assert(compare_layout_mappings(std::extents<T1, 5>(), std::extents<T2, 5, D>(5)).does_not_match());
65   static_assert(compare_layout_mappings(std::extents<T1, 5>(), std::extents<T2, 5, 1>()).does_not_match());
66 
67   static_assert(compare_layout_mappings(std::extents<T1, D, D>(5, 5), std::extents<T2, D>(5)).does_not_match());
68   static_assert(compare_layout_mappings(std::extents<T1, 5, D>(5), std::extents<T2, D>(5)).does_not_match());
69   static_assert(compare_layout_mappings(std::extents<T1, 5, 5>(), std::extents<T2, 5>()).does_not_match());
70 }
71 
72 template <class T1, class T2>
73 constexpr void test_comparison_same_rank() {
74   constexpr size_t D = std::dynamic_extent;
75 
76   test_comparison(true, std::extents<T1>(), std::extents<T2>());
77 
78   test_comparison(true, std::extents<T1, D>(5), std::extents<T2, D>(5));
79   test_comparison(true, std::extents<T1, 5>(), std::extents<T2, D>(5));
80   test_comparison(true, std::extents<T1, D>(5), std::extents<T2, 5>());
81   test_comparison(true, std::extents<T1, 5>(), std::extents< T2, 5>());
82   test_comparison(false, std::extents<T1, D>(5), std::extents<T2, D>(7));
83   test_comparison(false, std::extents<T1, 5>(), std::extents<T2, D>(7));
84   test_comparison(false, std::extents<T1, D>(5), std::extents<T2, 7>());
85   test_comparison(false, std::extents<T1, 5>(), std::extents<T2, 7>());
86 
87   test_comparison(true, std::extents<T1, D, D, D, D, D>(5, 6, 7, 8, 9), std::extents<T2, D, D, D, D, D>(5, 6, 7, 8, 9));
88   test_comparison(true, std::extents<T1, D, 6, D, 8, D>(5, 7, 9), std::extents<T2, 5, D, D, 8, 9>(6, 7));
89   test_comparison(true, std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9), std::extents<T2, 5, 6, 7, 8, 9>());
90   test_comparison(
91       false, std::extents<T1, D, D, D, D, D>(5, 6, 7, 8, 9), std::extents<T2, D, D, D, D, D>(5, 6, 3, 8, 9));
92   test_comparison(false, std::extents<T1, D, 6, D, 8, D>(5, 7, 9), std::extents<T2, 5, D, D, 3, 9>(6, 7));
93   test_comparison(false, std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9), std::extents<T2, 5, 6, 7, 3, 9>());
94 }
95 
96 template <class T1, class T2>
97 constexpr void test_comparison() {
98   test_comparison_same_rank<T1, T2>();
99   test_comparison_different_rank<T1, T2>();
100 }
101 
102 constexpr bool test() {
103   test_comparison<int, int>();
104   test_comparison<int, size_t>();
105   test_comparison<size_t, int>();
106   test_comparison<size_t, long>();
107   return true;
108 }
109 
110 int main(int, char**) {
111   test();
112   static_assert(test());
113   return 0;
114 }
115