1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
//===---------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===---------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// <span>
// template <class It>
// constexpr explicit(Extent != dynamic_extent) span(It first, size_type count);
// If Extent is not equal to dynamic_extent, then count shall be equal to Extent.
//
#include <span>
#include <cassert>
#include <iterator>
#include <type_traits>
template <size_t Extent>
constexpr void test_constructibility() {
struct Other {};
static_assert(std::is_constructible_v<std::span<int, Extent>, int*, size_t>);
static_assert(!std::is_constructible_v<std::span<int, Extent>, const int*, size_t>);
static_assert(std::is_constructible_v<std::span<const int, Extent>, int*, size_t>);
static_assert(std::is_constructible_v<std::span<const int, Extent>, const int*, size_t>);
static_assert(!std::is_constructible_v<std::span<int, Extent>, volatile int*, size_t>);
static_assert(!std::is_constructible_v<std::span<int, Extent>, const volatile int*, size_t>);
static_assert(!std::is_constructible_v<std::span<const int, Extent>, volatile int*, size_t>);
static_assert(!std::is_constructible_v<std::span<const int, Extent>, const volatile int*, size_t>);
static_assert(!std::is_constructible_v<std::span<volatile int, Extent>, const int*, size_t>);
static_assert(!std::is_constructible_v<std::span<volatile int, Extent>, const volatile int*, size_t>);
static_assert(
!std::is_constructible_v<std::span<int, Extent>, double*, size_t>); // iterator type differs from span type
static_assert(!std::is_constructible_v<std::span<int, Extent>, size_t, size_t>);
static_assert(!std::is_constructible_v<std::span<int, Extent>, Other*, size_t>); // unrelated iterator type
}
template <class T>
constexpr bool test_ctor() {
T val[2] = {};
auto s1 = std::span<T>(val, 2);
auto s2 = std::span<T, 2>(val, 2);
assert(s1.data() == std::data(val) && s1.size() == std::size(val));
assert(s2.data() == std::data(val) && s2.size() == std::size(val));
return true;
}
constexpr bool test() {
test_constructibility<std::dynamic_extent>();
test_constructibility<3>();
struct A {};
test_ctor<int>();
test_ctor<A>();
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
|
