1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
10
11 // <span>
12
13 // constexpr reverse_iterator rend() const noexcept;
14 // constexpr const_reverse_iterator crend() const noexcept;
15
16 #include <span>
17 #include <cassert>
18 #include <string>
19
20 #include "test_macros.h"
21
22 template <class Span>
testConstexprSpan(Span s)23 constexpr bool testConstexprSpan(Span s)
24 {
25 bool ret = true;
26 typename Span::reverse_iterator e = s. rend();
27 typename Span::const_reverse_iterator ce = s.crend();
28 if (s.empty())
29 {
30 ret = ret && ( e == s.rbegin());
31 ret = ret && (ce == s.crbegin());
32 }
33 else
34 {
35 ret = ret && ( e != s.rbegin());
36 ret = ret && (ce != s.crbegin());
37 }
38
39 ret = ret && (( e - s.rbegin()) == s.size());
40 ret = ret && ((ce - s.crbegin()) == s.size());
41
42 ret = ret && (e == ce);
43 return ret;
44 }
45
46 template <class Span>
testRuntimeSpan(Span s)47 void testRuntimeSpan(Span s)
48 {
49 typename Span::reverse_iterator e = s. rend();
50 typename Span::const_reverse_iterator ce = s.crend();
51 if (s.empty())
52 {
53 assert( e == s.rbegin());
54 assert(ce == s.crbegin());
55 }
56 else
57 {
58 assert( e != s.rbegin());
59 assert(ce != s.crbegin());
60 }
61
62 assert(( e - s.rbegin()) == s.size());
63 assert((ce - s.crbegin()) == s.size());
64
65 assert(e == ce);
66 }
67
68
69 struct A{};
operator ==(A,A)70 bool operator==(A, A) {return true;}
71
72 constexpr int iArr1[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
73 int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
74
75
main()76 int main()
77 {
78 static_assert(testConstexprSpan(std::span<int>()), "");
79 static_assert(testConstexprSpan(std::span<long>()), "");
80 static_assert(testConstexprSpan(std::span<double>()), "");
81 static_assert(testConstexprSpan(std::span<A>()), "");
82 static_assert(testConstexprSpan(std::span<std::string>()), "");
83
84 static_assert(testConstexprSpan(std::span<int, 0>()), "");
85 static_assert(testConstexprSpan(std::span<long, 0>()), "");
86 static_assert(testConstexprSpan(std::span<double, 0>()), "");
87 static_assert(testConstexprSpan(std::span<A, 0>()), "");
88 static_assert(testConstexprSpan(std::span<std::string, 0>()), "");
89
90 static_assert(testConstexprSpan(std::span<const int>(iArr1, 1)), "");
91 static_assert(testConstexprSpan(std::span<const int>(iArr1, 2)), "");
92 static_assert(testConstexprSpan(std::span<const int>(iArr1, 3)), "");
93 static_assert(testConstexprSpan(std::span<const int>(iArr1, 4)), "");
94 static_assert(testConstexprSpan(std::span<const int>(iArr1, 5)), "");
95
96
97 testRuntimeSpan(std::span<int> ());
98 testRuntimeSpan(std::span<long> ());
99 testRuntimeSpan(std::span<double> ());
100 testRuntimeSpan(std::span<A> ());
101 testRuntimeSpan(std::span<std::string>());
102
103 testRuntimeSpan(std::span<int, 0> ());
104 testRuntimeSpan(std::span<long, 0> ());
105 testRuntimeSpan(std::span<double, 0> ());
106 testRuntimeSpan(std::span<A, 0> ());
107 testRuntimeSpan(std::span<std::string, 0>());
108
109 testRuntimeSpan(std::span<int>(iArr2, 1));
110 testRuntimeSpan(std::span<int>(iArr2, 2));
111 testRuntimeSpan(std::span<int>(iArr2, 3));
112 testRuntimeSpan(std::span<int>(iArr2, 4));
113 testRuntimeSpan(std::span<int>(iArr2, 5));
114
115 std::string s;
116 testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
117 testRuntimeSpan(std::span<std::string>(&s, 1));
118 }
119