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 // constexpr reverse_iterator rbegin() const noexcept;
13 // constexpr const_reverse_iterator crbegin() const noexcept;
14
15 #include <span>
16 #include <cassert>
17 #include <string>
18
19 #include "test_macros.h"
20
21 template <class Span>
testConstexprSpan(Span s)22 constexpr bool testConstexprSpan(Span s)
23 {
24 bool ret = true;
25 typename Span::reverse_iterator b = s.rbegin();
26 if (s.empty())
27 {
28 ret = ret && ( b == s.rend());
29 }
30 else
31 {
32 const typename Span::size_type last = s.size() - 1;
33 ret = ret && ( *b == s[last]);
34 ret = ret && (&*b == &s[last]);
35 }
36 return ret;
37 }
38
39
40 template <class Span>
testRuntimeSpan(Span s)41 void testRuntimeSpan(Span s)
42 {
43 typename Span::reverse_iterator b = s.rbegin();
44 if (s.empty())
45 {
46 assert(b == s.rend());
47 }
48 else
49 {
50 const typename Span::size_type last = s.size() - 1;
51 assert( *b == s[last]);
52 assert(&*b == &s[last]);
53 }
54 }
55
56
57 struct A{};
operator ==(A,A)58 bool operator==(A, A) {return true;}
59
60 constexpr int iArr1[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
61 int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
62
63
main(int,char **)64 int main(int, char**)
65 {
66 static_assert(testConstexprSpan(std::span<int>()), "");
67 static_assert(testConstexprSpan(std::span<long>()), "");
68 static_assert(testConstexprSpan(std::span<double>()), "");
69 static_assert(testConstexprSpan(std::span<A>()), "");
70 static_assert(testConstexprSpan(std::span<std::string>()), "");
71
72 static_assert(testConstexprSpan(std::span<int, 0>()), "");
73 static_assert(testConstexprSpan(std::span<long, 0>()), "");
74 static_assert(testConstexprSpan(std::span<double, 0>()), "");
75 static_assert(testConstexprSpan(std::span<A, 0>()), "");
76 static_assert(testConstexprSpan(std::span<std::string, 0>()), "");
77
78 static_assert(testConstexprSpan(std::span<const int>(iArr1, 1)), "");
79 static_assert(testConstexprSpan(std::span<const int>(iArr1, 2)), "");
80 static_assert(testConstexprSpan(std::span<const int>(iArr1, 3)), "");
81 static_assert(testConstexprSpan(std::span<const int>(iArr1, 4)), "");
82 static_assert(testConstexprSpan(std::span<const int>(iArr1, 5)), "");
83
84
85 testRuntimeSpan(std::span<int> ());
86 testRuntimeSpan(std::span<long> ());
87 testRuntimeSpan(std::span<double> ());
88 testRuntimeSpan(std::span<A> ());
89 testRuntimeSpan(std::span<std::string>());
90
91 testRuntimeSpan(std::span<int, 0> ());
92 testRuntimeSpan(std::span<long, 0> ());
93 testRuntimeSpan(std::span<double, 0> ());
94 testRuntimeSpan(std::span<A, 0> ());
95 testRuntimeSpan(std::span<std::string, 0>());
96
97 testRuntimeSpan(std::span<int>(iArr2, 1));
98 testRuntimeSpan(std::span<int>(iArr2, 2));
99 testRuntimeSpan(std::span<int>(iArr2, 3));
100 testRuntimeSpan(std::span<int>(iArr2, 4));
101 testRuntimeSpan(std::span<int>(iArr2, 5));
102
103 std::string s;
104 testRuntimeSpan(std::span<std::string>(&s, static_cast<std::size_t>(0)));
105 testRuntimeSpan(std::span<std::string>(&s, 1));
106
107 return 0;
108 }
109