xref: /llvm-project/libcxx/test/std/containers/views/views.span/span.objectrep/as_bytes.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 // UNSUPPORTED: c++03, c++11, c++14, c++17
9 
10 // <span>
11 
12 // template <class ElementType, size_t Extent>
13 //     span<const byte,
14 //          Extent == dynamic_extent
15 //              ? dynamic_extent
16 //              : sizeof(ElementType) * Extent>
17 //     as_bytes(span<ElementType, Extent> s) noexcept;
18 
19 #include <cassert>
20 #include <cstddef>
21 #include <span>
22 #include <string>
23 
24 #include "test_macros.h"
25 
26 template<typename Span>
27 void testRuntimeSpan(Span sp)
28 {
29     ASSERT_NOEXCEPT(std::as_bytes(sp));
30 
31     auto spBytes = std::as_bytes(sp);
32     using SB = decltype(spBytes);
33     ASSERT_SAME_TYPE(const std::byte, typename SB::element_type);
34 
35     if constexpr (sp.extent == std::dynamic_extent)
36         assert(spBytes.extent == std::dynamic_extent);
37     else
38         assert(spBytes.extent == sizeof(typename Span::element_type) * sp.extent);
39 
40     assert((void *) spBytes.data() == (void *) sp.data());
41     assert(spBytes.size() == sp.size_bytes());
42 }
43 
44 struct A{};
45 int iArr2[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
46 
47 int main(int, char**)
48 {
49     testRuntimeSpan(std::span<int>        ());
50     testRuntimeSpan(std::span<long>       ());
51     testRuntimeSpan(std::span<double>     ());
52     testRuntimeSpan(std::span<A>          ());
53     testRuntimeSpan(std::span<std::string>());
54 
55     testRuntimeSpan(std::span<int, 0>        ());
56     testRuntimeSpan(std::span<long, 0>       ());
57     testRuntimeSpan(std::span<double, 0>     ());
58     testRuntimeSpan(std::span<A, 0>          ());
59     testRuntimeSpan(std::span<std::string, 0>());
60 
61     testRuntimeSpan(std::span<int>(iArr2, 1));
62     testRuntimeSpan(std::span<int>(iArr2, 2));
63     testRuntimeSpan(std::span<int>(iArr2, 3));
64     testRuntimeSpan(std::span<int>(iArr2, 4));
65     testRuntimeSpan(std::span<int>(iArr2, 5));
66 
67     testRuntimeSpan(std::span<int, 1>(iArr2 + 5, 1));
68     testRuntimeSpan(std::span<int, 2>(iArr2 + 4, 2));
69     testRuntimeSpan(std::span<int, 3>(iArr2 + 3, 3));
70     testRuntimeSpan(std::span<int, 4>(iArr2 + 2, 4));
71     testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5));
72 
73     std::string s;
74     testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0));
75     testRuntimeSpan(std::span<std::string>(&s, 1));
76 
77   return 0;
78 }
79