libcxx/test/std/numerics/rand/rand.adapt/rand.adapt.shuf/eval.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <random>
  10
  11 // template<class Engine, size_t k>
  12 // class shuffle_order_engine
  13
  14 // result_type operator()();
  15
  16 #include <random>
  17 #include <cassert>
  18
  19 #include "test_macros.h"
  20
  21 template <class UIntType, UIntType Min, UIntType Max>
  22 class rand1
  23 {
  24 public:
  25     // types
  26     typedef UIntType result_type;
  27
  28 private:
  29     result_type x_;
  30
  31     static_assert(Min < Max, "rand1 invalid parameters");
  32 public:
  33
  34 #if TEST_STD_VER < 11 && defined(_LIBCPP_VERSION)
  35     // Workaround for lack of constexpr in C++03
  36     static const result_type _Min = Min;
  37     static const result_type _Max = Max;
  38 #endif
  39
  40     static TEST_CONSTEXPR result_type min() {return Min;}
  41     static TEST_CONSTEXPR result_type max() {return Max;}
  42
  43     explicit rand1(result_type sd = Min) : x_(sd)
  44     {
  45         if (x_ > Max)
  46             x_ = Max;
  47     }
  48
  49     result_type operator()()
  50     {
  51         result_type r = x_;
  52         if (x_ < Max)
  53             ++x_;
  54         else
  55             x_ = Min;
  56         return r;
  57     }
  58 };
  59
  60 void
  61 test1()
  62 {
  63    typedef std::knuth_b E;
  64
  65     E e;
  66     assert(e() == 152607844u);
  67 }
  68
  69 void
  70 test2()
  71 {
  72     typedef rand1<unsigned long long, 0, 0xFFFFFFFFFFFFFFFFull> E0;
  73     typedef std::shuffle_order_engine<E0, 101> E;
  74     E e;
  75     e.discard(400);
  76     assert(e() == 501);
  77 }
  78
  79 void
  80 test3()
  81 {
  82     typedef rand1<unsigned long long, 0, 0xFFFFFFFFFFFFFFFFull> E0;
  83     typedef std::shuffle_order_engine<E0, 100> E;
  84     E e;
  85     e.discard(400);
  86     assert(e() == 500);
  87 }
  88
  89 int main(int, char**)
  90 {
  91     test1();
  92     test2();
  93     test3();
  94
  95   return 0;
  96 }