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 <bitset>
22 #include <cassert>
23 #include <type_traits>
24 
25 template <std::size_t N>
26 void
test()27 test()
28 {
29     typedef std::bitset<N> T;
30     typedef std::hash<T> H;
31     static_assert((std::is_base_of<std::unary_function<T, std::size_t>,
32                                    H>::value), "");
33     H h;
34     T bs(static_cast<unsigned long long>(N));
35     assert(h(bs) == N);
36 }
37 
main()38 int main()
39 {
40     test<0>();
41     test<10>();
42     test<100>();
43     test<1000>();
44 }
45