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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;
// result_type operator()();
#include <random>
#include <cassert>
#include "test_macros.h"
int main(int, char**)
{
typedef unsigned long long T;
// m might overflow, but the overflow is OK so it shouldn't use schrage's algorithm
typedef std::linear_congruential_engine<T, 25214903917ull, 1, (1ull<<48)> E1;
E1 e1;
// make sure the right algorithm was used
assert(e1() == 25214903918);
assert(e1() == 205774354444503);
assert(e1() == 158051849450892);
// make sure result is in bounds
assert(e1() < (1ull<<48));
assert(e1() < (1ull<<48));
assert(e1() < (1ull<<48));
assert(e1() < (1ull<<48));
assert(e1() < (1ull<<48));
// m might overflow. The overflow is not OK and result will be in bounds
// so we should use shrage's algorithm
typedef std::linear_congruential_engine<T, (1ull<<2), 0, (1ull<<63) + 1> E2;
E2 e2;
// make sure shrage's algorithm is used (it would be 0s otherwise)
assert(e2() == 4);
assert(e2() == 16);
assert(e2() == 64);
// make sure result is in bounds
assert(e2() < (1ull<<48) + 1);
assert(e2() < (1ull<<48) + 1);
assert(e2() < (1ull<<48) + 1);
assert(e2() < (1ull<<48) + 1);
assert(e2() < (1ull<<48) + 1);
// m will not overflow so we should not use shrage's algorithm
typedef std::linear_congruential_engine<T, 1ull, 1, (1ull<<48)> E3;
E3 e3;
// make sure the correct algorithm was used
assert(e3() == 2);
assert(e3() == 3);
assert(e3() == 4);
// make sure result is in bounds
assert(e3() < (1ull<<48));
assert(e3() < (1ull<<48));
assert(e3() < (1ull<<48));
assert(e3() < (1ull<<48));
assert(e2() < (1ull<<48));
return 0;
}
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