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