xref: /llvm-project/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp (revision 33325524f5e80a898a7ae875e208a54af132001b)
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
10 // <optional>
11 
12 // template <class T> struct hash<optional<T>>;
13 
14 #include <optional>
15 #include <string>
16 #include <memory>
17 #include <cassert>
18 
19 #include "poisoned_hash_helper.h"
20 
21 #include "test_macros.h"
22 
23 struct A {};
24 struct B {};
25 
26 template <>
27 struct std::hash<B> {
28   std::size_t operator()(B const&) noexcept(false) { return 0; }
29 };
30 
31 int main(int, char**)
32 {
33     using std::optional;
34     const std::size_t nullopt_hash =
35         std::hash<optional<double>>{}(optional<double>{});
36 
37 
38     {
39         optional<B> opt;
40         ASSERT_NOT_NOEXCEPT(std::hash<optional<B>>()(opt));
41         ASSERT_NOT_NOEXCEPT(std::hash<optional<const B>>()(opt));
42     }
43 
44     {
45         typedef int T;
46         optional<T> opt;
47         assert(std::hash<optional<T>>{}(opt) == nullopt_hash);
48         opt = 2;
49         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));
50     }
51     {
52         typedef std::string T;
53         optional<T> opt;
54         assert(std::hash<optional<T>>{}(opt) == nullopt_hash);
55         opt = std::string("123");
56         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));
57     }
58     {
59         typedef std::unique_ptr<int> T;
60         optional<T> opt;
61         assert(std::hash<optional<T>>{}(opt) == nullopt_hash);
62         opt = std::unique_ptr<int>(new int(3));
63         assert(std::hash<optional<T>>{}(opt) == std::hash<T>{}(*opt));
64     }
65     {
66       test_hash_enabled<std::optional<int> >();
67       test_hash_enabled<std::optional<int*> >();
68       test_hash_enabled<std::optional<const int> >();
69       test_hash_enabled<std::optional<int* const> >();
70 
71       test_hash_disabled<std::optional<A>>();
72       test_hash_disabled<std::optional<const A>>();
73 
74       test_hash_enabled<std::optional<B>>();
75       test_hash_enabled<std::optional<const B>>();
76     }
77 
78   return 0;
79 }
80