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      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     typedef std::hash<T> H;
     32     static_assert((std::is_same<typename H::argument_type, T>::value), "" );
     33     static_assert((std::is_same<typename H::result_type, std::size_t>::value), "" );
     34     H h;
     35 
     36     std::size_t t0 = h(0.);
     37     std::size_t tn0 = h(-0.);
     38     std::size_t tp1 = h(static_cast<T>(0.1));
     39     std::size_t t1 = h(1);
     40     std::size_t tn1 = h(-1);
     41     std::size_t pinf = h(INFINITY);
     42     std::size_t ninf = h(-INFINITY);
     43     assert(t0 == tn0);
     44     assert(t0 != tp1);
     45     assert(t0 != t1);
     46     assert(t0 != tn1);
     47     assert(t0 != pinf);
     48     assert(t0 != ninf);
     49 
     50     assert(tp1 != t1);
     51     assert(tp1 != tn1);
     52     assert(tp1 != pinf);
     53     assert(tp1 != ninf);
     54 
     55     assert(t1 != tn1);
     56     assert(t1 != pinf);
     57     assert(t1 != ninf);
     58 
     59     assert(tn1 != pinf);
     60     assert(tn1 != ninf);
     61 
     62     assert(pinf != ninf);
     63 }
     64 
     65 int main()
     66 {
     67     test<float>();
     68     test<double>();
     69     test<long double>();
     70 }
     71