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 OtherMapping>
14// friend constexpr bool operator==(const mapping& x, const OtherMapping& y) noexcept;
15//
16// Constraints:
17// - layout-mapping-alike<OtherMapping> is satisfied.
18// - rank_ == OtherMapping::extents_type::rank() is true.
19// - OtherMapping::is_always_strided() is true.
20//
21// Preconditions: OtherMapping meets the layout mapping requirements ([mdspan.layout.policy.reqmts]).
22//
23// Returns: true if x.extents() == y.extents() is true, OFFSET(y) == 0 is true, and each of x.stride(r) == y.stride(r) is true for r in the range [0, x.extents().rank()). Otherwise, false.
24
25#include <mdspan>
26#include <cassert>
27#include <concepts>
28#include <type_traits>
29
30#include "test_macros.h"
31
32#include "../CustomTestLayouts.h"
33
34template <class E1, class E2>
35concept layout_mapping_comparable = requires(
36 E1 e1,
37 E2 e2,
38 std::array<typename E1::index_type, E1::rank()> s1,
39 std::array<typename E1::index_type, E1::rank()> s2) {
40 std::layout_stride::mapping<E1>(e1, s1) == std::layout_stride::mapping<E2>(e2, s2);
41};
42
43template <class T1, class T2>
44constexpr void test_comparison_different_rank() {
45 constexpr size_t D = std::dynamic_extent;
46
47 // sanity check same rank
48 static_assert(layout_mapping_comparable<std::extents<T1, D>, std::extents<T2, D>>);
49 static_assert(layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, D>>);
50 static_assert(layout_mapping_comparable<std::extents<T1, D>, std::extents<T2, 5>>);
51 static_assert(layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, 5>>);
52
53 // not equality comparable when rank is not the same
54 static_assert(!layout_mapping_comparable<std::extents<T1>, std::extents<T2, D>>);
55 static_assert(!layout_mapping_comparable<std::extents<T1>, std::extents<T2, 1>>);
56 static_assert(!layout_mapping_comparable<std::extents<T1, D>, std::extents<T2>>);
57 static_assert(!layout_mapping_comparable<std::extents<T1, 1>, std::extents<T2>>);
58 static_assert(!layout_mapping_comparable<std::extents<T1, D>, std::extents<T2, D, D>>);
59 static_assert(!layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, 5, D>>);
60 static_assert(!layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, 5, 1>>);
61 static_assert(!layout_mapping_comparable<std::extents<T1, D, D>, std::extents<T2, D>>);
62 static_assert(!layout_mapping_comparable<std::extents<T1, 5, D>, std::extents<T2, 5>>);
63 static_assert(!layout_mapping_comparable<std::extents<T1, 5, 1>, std::extents<T2, 5>>);
64}
65
66template <class To, class From>
67constexpr void test_comparison(
68 bool equal,
69 To dest_exts,
70 From src_exts,
71 std::array<int, To::rank()> dest_strides,
72 std::array<int, From::rank()> src_strides) {
73 std::layout_stride::mapping<To> dest(dest_exts, dest_strides);
74 std::layout_stride::mapping<From> src(src_exts, src_strides);
75 ASSERT_NOEXCEPT(dest == src);
76 assert((dest == src) == equal);
77 assert((dest != src) == !equal);
78}
79
80template <class T1, class T2>
81constexpr void test_comparison_same_rank() {
82 constexpr size_t D = std::dynamic_extent;
83
84 test_comparison(true, std::extents<T1>(), std::extents<T2>(), std::array<int, 0>{}, std::array<int, 0>{});
85
86 test_comparison(true, std::extents<T1, D>(5), std::extents<T2, D>(5), std::array<int, 1>{1}, std::array<int, 1>{1});
87 test_comparison(true, std::extents<T1, D>(0), std::extents<T2, D>(0), std::array<int, 1>{1}, std::array<int, 1>{1});
88 test_comparison(true, std::extents<T1, 5>(), std::extents<T2, D>(5), std::array<int, 1>{3}, std::array<int, 1>{3});
89 test_comparison(true, std::extents<T1, D>(5), std::extents<T2, 5>(), std::array<int, 1>{1}, std::array<int, 1>{1});
90 test_comparison(true, std::extents<T1, 5>(), std::extents< T2, 5>(), std::array<int, 1>{1}, std::array<int, 1>{1});
91 test_comparison(false, std::extents<T1, 5>(), std::extents<T2, D>(5), std::array<int, 1>{2}, std::array<int, 1>{1});
92 test_comparison(false, std::extents<T1, D>(5), std::extents<T2, D>(5), std::array<int, 1>{2}, std::array<int, 1>{1});
93 test_comparison(false, std::extents<T1, D>(5), std::extents<T2, D>(7), std::array<int, 1>{1}, std::array<int, 1>{1});
94 test_comparison(false, std::extents<T1, 5>(), std::extents<T2, D>(7), std::array<int, 1>{1}, std::array<int, 1>{1});
95 test_comparison(false, std::extents<T1, D>(5), std::extents<T2, 7>(), std::array<int, 1>{1}, std::array<int, 1>{1});
96 test_comparison(false, std::extents<T1, 5>(), std::extents<T2, 7>(), std::array<int, 1>{1}, std::array<int, 1>{1});
97
98 test_comparison(
99 true,
100 std::extents<T1, D, D, D, D, D>(5, 6, 7, 8, 9),
101 std::extents<T2, D, D, D, D, D>(5, 6, 7, 8, 9),
102 std::array<int, 5>{2, 20, 200, 2000, 20000},
103 std::array<int, 5>{2, 20, 200, 2000, 20000});
104 test_comparison(
105 true,
106 std::extents<T1, D, 6, D, 8, D>(5, 7, 9),
107 std::extents<T2, 5, D, D, 8, 9>(6, 7),
108 std::array<int, 5>{2, 20, 200, 2000, 20000},
109 std::array<int, 5>{2, 20, 200, 2000, 20000});
110 test_comparison(
111 true,
112 std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9),
113 std::extents<T2, 5, 6, 7, 8, 9>(),
114 std::array<int, 5>{2, 20, 200, 2000, 20000},
115 std::array<int, 5>{2, 20, 200, 2000, 20000});
116 test_comparison(
117 false,
118 std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9),
119 std::extents<T2, 5, 6, 7, 8, 9>(),
120 std::array<int, 5>{2, 20, 200, 20000, 2000},
121 std::array<int, 5>{2, 20, 200, 2000, 20000});
122 test_comparison(
123 false,
124 std::extents<T1, D, D, D, D, D>(5, 6, 7, 8, 9),
125 std::extents<T2, D, D, D, D, D>(5, 6, 3, 8, 9),
126 std::array<int, 5>{2, 20, 200, 2000, 20000},
127 std::array<int, 5>{2, 20, 200, 2000, 20000});
128 test_comparison(
129 false,
130 std::extents<T1, D, 6, D, 8, D>(5, 7, 9),
131 std::extents<T2, 5, D, D, 3, 9>(6, 7),
132 std::array<int, 5>{2, 20, 200, 2000, 20000},
133 std::array<int, 5>{2, 20, 200, 2000, 20000});
134 test_comparison(
135 false,
136 std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9),
137 std::extents<T2, 5, 6, 7, 3, 9>(),
138 std::array<int, 5>{2, 20, 200, 2000, 20000},
139 std::array<int, 5>{2, 20, 200, 2000, 20000});
140}
141
142template <class OtherLayout, class E1, class E2, class... OtherArgs>
143constexpr void test_comparison_with(
144 bool expect_equal, E1 e1, std::array<typename E1::index_type, E1::rank()> strides, E2 e2, OtherArgs... other_args) {
145 std::layout_stride::mapping<E1> map(e1, strides);
146 typename OtherLayout::template mapping<E2> other_map(e2, other_args...);
147
148 assert((map == other_map) == expect_equal);
149}
150
151template <class OtherLayout>
152constexpr void test_comparison_with() {
153 constexpr size_t D = std::dynamic_extent;
154 bool is_left_based =
155 std::is_same_v<OtherLayout, std::layout_left> || std::is_same_v<OtherLayout, always_convertible_layout>;
156 test_comparison_with<OtherLayout>(true, std::extents<int>(), std::array<int, 0>{}, std::extents<unsigned>());
157 test_comparison_with<OtherLayout>(true, std::extents<int, 5>(), std::array<int, 1>{1}, std::extents<unsigned, 5>());
158 test_comparison_with<OtherLayout>(true, std::extents<int, D>(5), std::array<int, 1>{1}, std::extents<unsigned, 5>());
159 test_comparison_with<OtherLayout>(false, std::extents<int, D>(5), std::array<int, 1>{2}, std::extents<unsigned, 5>());
160 test_comparison_with<OtherLayout>(
161 is_left_based, std::extents<int, D, D>(5, 7), std::array<int, 2>{1, 5}, std::extents<unsigned, D, D>(5, 7));
162 test_comparison_with<OtherLayout>(
163 !is_left_based, std::extents<int, D, D>(5, 7), std::array<int, 2>{7, 1}, std::extents<unsigned, D, D>(5, 7));
164 test_comparison_with<OtherLayout>(
165 false, std::extents<int, D, D>(5, 7), std::array<int, 2>{8, 1}, std::extents<unsigned, D, D>(5, 7));
166
167 if constexpr (std::is_same_v<OtherLayout, always_convertible_layout>) {
168 // test layout with strides not equal to product of extents
169 test_comparison_with<OtherLayout>(
170 true, std::extents<int, D, D>(5, 7), std::array<int, 2>{2, 10}, std::extents<unsigned, D, D>(5, 7), 0, 2);
171 // make sure that offset != 0 results in false
172 test_comparison_with<OtherLayout>(
173 false, std::extents<int, D, D>(5, 7), std::array<int, 2>{2, 10}, std::extents<unsigned, D, D>(5, 7), 1, 2);
174 }
175}
176
177template <class T1, class T2>
178constexpr void test_comparison_index_type() {
179 test_comparison_same_rank<T1, T2>();
180 test_comparison_different_rank<T1, T2>();
181 test_comparison_with<std::layout_right>();
182 test_comparison_with<std::layout_left>();
183 test_comparison_with<always_convertible_layout>();
184}
185
186constexpr bool test() {
187 test_comparison_index_type<int, int>();
188 test_comparison_index_type<int, size_t>();
189 test_comparison_index_type<size_t, int>();
190 test_comparison_index_type<size_t, long>();
191 return true;
192}
193
194int main(int, char**) {
195 test();
196 static_assert(test());
197 return 0;
198}
199

source code of libcxx/test/std/containers/views/mdspan/layout_stride/comparison.pass.cpp