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 // <random>
11 
12 // template<class Engine, size_t k>
13 // class shuffle_order_engine
14 
15 // result_type operator()();
16 
17 #include <random>
18 #include <cassert>
19 
20 template <class UIntType, UIntType Min, UIntType Max>
21 class rand1
22 {
23 public:
24     // types
25     typedef UIntType result_type;
26 
27 private:
28     result_type x_;
29 
30     static_assert(Min < Max, "rand1 invalid parameters");
31 public:
32 
33 #ifdef _LIBCPP_HAS_NO_CONSTEXPR
34     // Workaround for lack of constexpr in C++03
35     static const result_type _Min = Min;
36     static const result_type _Max = Max;
37 #endif
38 
min()39     static _LIBCPP_CONSTEXPR result_type min() {return Min;}
max()40     static _LIBCPP_CONSTEXPR result_type max() {return Max;}
41 
rand1(result_type sd=Min)42     explicit rand1(result_type sd = Min) : x_(sd)
43     {
44         if (x_ > Max)
45             x_ = Max;
46     }
47 
operator ()()48     result_type operator()()
49     {
50         result_type r = x_;
51         if (x_ < Max)
52             ++x_;
53         else
54             x_ = Min;
55         return r;
56     }
57 };
58 
59 void
test1()60 test1()
61 {
62    typedef std::knuth_b E;
63 
64     E e;
65     assert(e() == 152607844u);
66 }
67 
68 void
test2()69 test2()
70 {
71     typedef rand1<unsigned long long, 0, 0xFFFFFFFFFFFFFFFFull> E0;
72     typedef std::shuffle_order_engine<E0, 101> E;
73     E e;
74     e.discard(400);
75     assert(e() == 501);
76 }
77 
78 void
test3()79 test3()
80 {
81     typedef rand1<unsigned long long, 0, 0xFFFFFFFFFFFFFFFFull> E0;
82     typedef std::shuffle_order_engine<E0, 100> E;
83     E e;
84     e.discard(400);
85     assert(e() == 500);
86 }
87 
main()88 int main()
89 {
90     test1();
91     test2();
92     test3();
93 }
94