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 
10 // <functional>
11 
12 // template <class T>
13 // struct hash
14 //     : public unary_function<T, size_t>
15 // {
16 //     size_t operator()(T val) const;
17 // };
18 
19 // Not very portable
20 
21 #include <functional>
22 #include <cassert>
23 #include <type_traits>
24 #include <limits>
25 #include <cmath>
26 
27 template <class T>
28 void
29 test()
30 {
31     static_assert((std::is_base_of<std::unary_function<T, std::size_t>,
32                                    std::hash<T> >::value), "");
33     std::hash<T> h;
34     std::size_t t0 = h(0.);
35     std::size_t tn0 = h(-0.);
36     std::size_t tp1 = h(0.1);
37     std::size_t t1 = h(1);
38     std::size_t tn1 = h(-1);
39     std::size_t pinf = h(INFINITY);
40     std::size_t ninf = h(-INFINITY);
41     assert(t0 == tn0);
42     assert(t0 != tp1);
43     assert(t0 != t1);
44     assert(t0 != tn1);
45     assert(t0 != pinf);
46     assert(t0 != ninf);
47 
48     assert(tp1 != t1);
49     assert(tp1 != tn1);
50     assert(tp1 != pinf);
51     assert(tp1 != ninf);
52 
53     assert(t1 != tn1);
54     assert(t1 != pinf);
55     assert(t1 != ninf);
56 
57     assert(tn1 != pinf);
58     assert(tn1 != ninf);
59 
60     assert(pinf != ninf);
61 }
62 
63 int main()
64 {
65     test<float>();
66     test<double>();
67     test<long double>();
68 }
69