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// constexpr index_type required_span_size() const noexcept;
14//
15// Returns: extents().fwd-prod-of-extents(extents_type::rank()).
16
17#include <cassert>
18#include <cstddef>
19#include <cstdint>
20#include <mdspan>
21
22#include "test_macros.h"
23
24template <class E>
25constexpr void test_required_span_size(E e, typename E::index_type expected_size) {
26 using M = std::layout_left::mapping<E>;
27 const M m(e);
28
29 ASSERT_NOEXCEPT(m.required_span_size());
30 assert(m.required_span_size() == expected_size);
31}
32
33constexpr bool test() {
34 constexpr size_t D = std::dynamic_extent;
35 test_required_span_size(std::extents<int>(), 1);
36 test_required_span_size(std::extents<unsigned, D>(0), 0);
37 test_required_span_size(std::extents<unsigned, D>(1), 1);
38 test_required_span_size(std::extents<unsigned, D>(7), 7);
39 test_required_span_size(std::extents<unsigned, 7>(), 7);
40 test_required_span_size(std::extents<unsigned, 7, 8>(), 56);
41 test_required_span_size(std::extents<int64_t, D, 8, D, D>(7, 9, 10), 5040);
42 test_required_span_size(std::extents<int64_t, 1, 8, D, D>(9, 10), 720);
43 test_required_span_size(std::extents<int64_t, 1, 0, D, D>(9, 10), 0);
44 return true;
45}
46
47int main(int, char**) {
48 test();
49 static_assert(test());
50 return 0;
51}
52

source code of libcxx/test/std/containers/views/mdspan/layout_left/required_span_size.pass.cpp