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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// <random>
// template <class UIntType, UIntType a, UIntType c, UIntType m>
// class linear_congruential_engine
// {
// public:
// engine characteristics
// static constexpr result_type multiplier = a;
// static constexpr result_type increment = c;
// static constexpr result_type modulus = m;
// static constexpr result_type min() { return c == 0u ? 1u: 0u;}
// static constexpr result_type max() { return m - 1u;}
// static constexpr result_type default_seed = 1u;
#include <random>
#include <cassert>
#include <climits>
#include <type_traits>
#include "test_macros.h"
template <class T>
void where(const T &) {}
template <class T, T a, T c, T m>
void
test1()
{
typedef std::linear_congruential_engine<T, a, c, m> LCE;
typedef typename LCE::result_type result_type;
static_assert((LCE::multiplier == a), "");
static_assert((LCE::increment == c), "");
static_assert((LCE::modulus == m), "");
#if TEST_STD_VER >= 11
static_assert((LCE::min() == (c == 0u ? 1u: 0u)), "");
#else
assert((LCE::min() == (c == 0u ? 1u: 0u)));
#endif
TEST_DIAGNOSTIC_PUSH
TEST_MSVC_DIAGNOSTIC_IGNORED(4310) // cast truncates constant value
#if TEST_STD_VER >= 11
static_assert((LCE::max() == result_type(m - 1u)), "");
#else
assert((LCE::max() == result_type(m - 1u)));
#endif
TEST_DIAGNOSTIC_POP
static_assert((LCE::default_seed == 1), "");
where(LCE::multiplier);
where(LCE::increment);
where(LCE::modulus);
where(LCE::default_seed);
}
template <class T>
void
test()
{
const int W = sizeof(T) * CHAR_BIT;
const T M(static_cast<T>(-1));
const T A(static_cast<T>((static_cast<T>(1) << (W / 2)) - 1));
// Cases where m = 0
test1<T, 0, 0, 0>();
test1<T, A, 0, 0>();
test1<T, 0, 1, 0>();
test1<T, A, 1, 0>();
// Cases where m = 2^n for n < w
test1<T, 0, 0, 256>();
test1<T, 5, 0, 256>();
test1<T, 0, 1, 256>();
test1<T, 5, 1, 256>();
// Cases where m is odd and a = 0
test1<T, 0, 0, M>();
test1<T, 0, M - 2, M>();
test1<T, 0, M - 1, M>();
// Cases where m is odd and m % a <= m / a (Schrage)
test1<T, A, 0, M>();
test1<T, A, M - 2, M>();
test1<T, A, M - 1, M>();
}
template <class T>
void test_ext() {
const T M(static_cast<T>(-1));
// Cases where m is odd and m % a > m / a
test1<T, M - 2, 0, M>();
test1<T, M - 2, M - 2, M>();
test1<T, M - 2, M - 1, M>();
test1<T, M - 1, 0, M>();
test1<T, M - 1, M - 2, M>();
test1<T, M - 1, M - 1, M>();
}
int main(int, char**)
{
test<unsigned short>();
test_ext<unsigned short>();
test<unsigned int>();
test_ext<unsigned int>();
test<unsigned long>();
test_ext<unsigned long>();
test<unsigned long long>();
// This isn't implemented on platforms without __int128
#ifndef TEST_HAS_NO_INT128
test_ext<unsigned long long>();
#endif
return 0;
}
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