xref: /llvm-project/libcxx/test/std/containers/views/mdspan/layout_stride/comparison.pass.cpp (revision 5e19fd172063c8957a35c7fa3596620f79ebba97)
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 <span> // dynamic_extent
29 #include <type_traits>
30 
31 #include "test_macros.h"
32 
33 #include "../CustomTestLayouts.h"
34 
35 template <class E1, class E2>
36 concept layout_mapping_comparable = requires(
37     E1 e1,
38     E2 e2,
39     std::array<typename E1::index_type, E1::rank()> s1,
40     std::array<typename E1::index_type, E1::rank()> s2) {
41   std::layout_stride::mapping<E1>(e1, s1) == std::layout_stride::mapping<E2>(e2, s2);
42 };
43 
44 template <class T1, class T2>
45 constexpr void test_comparison_different_rank() {
46   constexpr size_t D = std::dynamic_extent;
47 
48   // sanity check same rank
49   static_assert(layout_mapping_comparable<std::extents<T1, D>, std::extents<T2, D>>);
50   static_assert(layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, D>>);
51   static_assert(layout_mapping_comparable<std::extents<T1, D>, std::extents<T2, 5>>);
52   static_assert(layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, 5>>);
53 
54   // not equality comparable when rank is not the same
55   static_assert(!layout_mapping_comparable<std::extents<T1>, std::extents<T2, D>>);
56   static_assert(!layout_mapping_comparable<std::extents<T1>, std::extents<T2, 1>>);
57   static_assert(!layout_mapping_comparable<std::extents<T1, D>, std::extents<T2>>);
58   static_assert(!layout_mapping_comparable<std::extents<T1, 1>, std::extents<T2>>);
59   static_assert(!layout_mapping_comparable<std::extents<T1, D>, std::extents<T2, D, D>>);
60   static_assert(!layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, 5, D>>);
61   static_assert(!layout_mapping_comparable<std::extents<T1, 5>, std::extents<T2, 5, 1>>);
62   static_assert(!layout_mapping_comparable<std::extents<T1, D, D>, std::extents<T2, D>>);
63   static_assert(!layout_mapping_comparable<std::extents<T1, 5, D>, std::extents<T2, 5>>);
64   static_assert(!layout_mapping_comparable<std::extents<T1, 5, 1>, std::extents<T2, 5>>);
65 }
66 
67 template <class To, class From>
68 constexpr void test_comparison(
69     bool equal,
70     To dest_exts,
71     From src_exts,
72     std::array<int, To::rank()> dest_strides,
73     std::array<int, From::rank()> src_strides) {
74   std::layout_stride::mapping<To> dest(dest_exts, dest_strides);
75   std::layout_stride::mapping<From> src(src_exts, src_strides);
76   ASSERT_NOEXCEPT(dest == src);
77   assert((dest == src) == equal);
78   assert((dest != src) == !equal);
79 }
80 
81 template <class T1, class T2>
82 constexpr void test_comparison_same_rank() {
83   constexpr size_t D = std::dynamic_extent;
84 
85   test_comparison(true, std::extents<T1>(), std::extents<T2>(), std::array<int, 0>{}, std::array<int, 0>{});
86 
87   test_comparison(true, std::extents<T1, D>(5), std::extents<T2, D>(5), std::array<int, 1>{1}, std::array<int, 1>{1});
88   test_comparison(true, std::extents<T1, D>(0), std::extents<T2, D>(0), std::array<int, 1>{1}, std::array<int, 1>{1});
89   test_comparison(true, std::extents<T1, 5>(), std::extents<T2, D>(5), std::array<int, 1>{3}, std::array<int, 1>{3});
90   test_comparison(true, std::extents<T1, D>(5), std::extents<T2, 5>(), std::array<int, 1>{1}, std::array<int, 1>{1});
91   test_comparison(true, std::extents<T1, 5>(), std::extents< T2, 5>(), std::array<int, 1>{1}, std::array<int, 1>{1});
92   test_comparison(false, std::extents<T1, 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>(5), std::array<int, 1>{2}, std::array<int, 1>{1});
94   test_comparison(false, std::extents<T1, D>(5), std::extents<T2, D>(7), std::array<int, 1>{1}, std::array<int, 1>{1});
95   test_comparison(false, std::extents<T1, 5>(), std::extents<T2, D>(7), std::array<int, 1>{1}, std::array<int, 1>{1});
96   test_comparison(false, std::extents<T1, D>(5), std::extents<T2, 7>(), std::array<int, 1>{1}, std::array<int, 1>{1});
97   test_comparison(false, std::extents<T1, 5>(), std::extents<T2, 7>(), std::array<int, 1>{1}, std::array<int, 1>{1});
98 
99   test_comparison(
100       true,
101       std::extents<T1, D, D, D, D, D>(5, 6, 7, 8, 9),
102       std::extents<T2, D, D, D, D, D>(5, 6, 7, 8, 9),
103       std::array<int, 5>{2, 20, 200, 2000, 20000},
104       std::array<int, 5>{2, 20, 200, 2000, 20000});
105   test_comparison(
106       true,
107       std::extents<T1, D, 6, D, 8, D>(5, 7, 9),
108       std::extents<T2, 5, D, D, 8, 9>(6, 7),
109       std::array<int, 5>{2, 20, 200, 2000, 20000},
110       std::array<int, 5>{2, 20, 200, 2000, 20000});
111   test_comparison(
112       true,
113       std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9),
114       std::extents<T2, 5, 6, 7, 8, 9>(),
115       std::array<int, 5>{2, 20, 200, 2000, 20000},
116       std::array<int, 5>{2, 20, 200, 2000, 20000});
117   test_comparison(
118       false,
119       std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9),
120       std::extents<T2, 5, 6, 7, 8, 9>(),
121       std::array<int, 5>{2, 20, 200, 20000, 2000},
122       std::array<int, 5>{2, 20, 200, 2000, 20000});
123   test_comparison(
124       false,
125       std::extents<T1, D, D, D, D, D>(5, 6, 7, 8, 9),
126       std::extents<T2, D, D, D, D, D>(5, 6, 3, 8, 9),
127       std::array<int, 5>{2, 20, 200, 2000, 20000},
128       std::array<int, 5>{2, 20, 200, 2000, 20000});
129   test_comparison(
130       false,
131       std::extents<T1, D, 6, D, 8, D>(5, 7, 9),
132       std::extents<T2, 5, D, D, 3, 9>(6, 7),
133       std::array<int, 5>{2, 20, 200, 2000, 20000},
134       std::array<int, 5>{2, 20, 200, 2000, 20000});
135   test_comparison(
136       false,
137       std::extents<T1, 5, 6, 7, 8, 9>(5, 6, 7, 8, 9),
138       std::extents<T2, 5, 6, 7, 3, 9>(),
139       std::array<int, 5>{2, 20, 200, 2000, 20000},
140       std::array<int, 5>{2, 20, 200, 2000, 20000});
141 }
142 
143 template <class OtherLayout, class E1, class E2, class... OtherArgs>
144 constexpr void test_comparison_with(
145     bool expect_equal, E1 e1, std::array<typename E1::index_type, E1::rank()> strides, E2 e2, OtherArgs... other_args) {
146   std::layout_stride::mapping<E1> map(e1, strides);
147   typename OtherLayout::template mapping<E2> other_map(e2, other_args...);
148 
149   assert((map == other_map) == expect_equal);
150 }
151 
152 template <class OtherLayout>
153 constexpr void test_comparison_with() {
154   constexpr size_t D = std::dynamic_extent;
155   bool is_left_based =
156       std::is_same_v<OtherLayout, std::layout_left> || std::is_same_v<OtherLayout, always_convertible_layout>;
157   test_comparison_with<OtherLayout>(true, std::extents<int>(), std::array<int, 0>{}, std::extents<unsigned>());
158   test_comparison_with<OtherLayout>(true, std::extents<int, 5>(), std::array<int, 1>{1}, std::extents<unsigned, 5>());
159   test_comparison_with<OtherLayout>(true, std::extents<int, D>(5), std::array<int, 1>{1}, std::extents<unsigned, 5>());
160   test_comparison_with<OtherLayout>(false, std::extents<int, D>(5), std::array<int, 1>{2}, std::extents<unsigned, 5>());
161   test_comparison_with<OtherLayout>(
162       is_left_based, std::extents<int, D, D>(5, 7), std::array<int, 2>{1, 5}, std::extents<unsigned, D, D>(5, 7));
163   test_comparison_with<OtherLayout>(
164       !is_left_based, std::extents<int, D, D>(5, 7), std::array<int, 2>{7, 1}, std::extents<unsigned, D, D>(5, 7));
165   test_comparison_with<OtherLayout>(
166       false, std::extents<int, D, D>(5, 7), std::array<int, 2>{8, 1}, std::extents<unsigned, D, D>(5, 7));
167 
168   if constexpr (std::is_same_v<OtherLayout, always_convertible_layout>) {
169     // test layout with strides not equal to product of extents
170     test_comparison_with<OtherLayout>(
171         true, std::extents<int, D, D>(5, 7), std::array<int, 2>{2, 10}, std::extents<unsigned, D, D>(5, 7), 0, 2);
172     // make sure that offset != 0 results in false
173     test_comparison_with<OtherLayout>(
174         false, std::extents<int, D, D>(5, 7), std::array<int, 2>{2, 10}, std::extents<unsigned, D, D>(5, 7), 1, 2);
175   }
176 }
177 
178 template <class T1, class T2>
179 constexpr void test_comparison_index_type() {
180   test_comparison_same_rank<T1, T2>();
181   test_comparison_different_rank<T1, T2>();
182   test_comparison_with<std::layout_right>();
183   test_comparison_with<std::layout_left>();
184   test_comparison_with<always_convertible_layout>();
185 }
186 
187 constexpr bool test() {
188   test_comparison_index_type<int, int>();
189   test_comparison_index_type<int, size_t>();
190   test_comparison_index_type<size_t, int>();
191   test_comparison_index_type<size_t, long>();
192   return true;
193 }
194 
195 int main(int, char**) {
196   test();
197   static_assert(test());
198   return 0;
199 }
200