-/* Copyright (c) 2019-2020. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2019-2021. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
int XbtRandom::uniform_int(int min, int max)
{
- unsigned long range = max - min + 1;
+ // The casts to unsigned are here to ensure that the value of range is correctly calculated, even when greater than
+ // INT_MAX. See the corresponding unit tests for examples.
+ unsigned long range = static_cast<unsigned>(max) - static_cast<unsigned>(min);
xbt_assert(min <= max,
"The minimum value for the uniform integer distribution must not be greater than the maximum value");
- xbt_assert(range > 0, "Overflow in the uniform integer distribution, please use a smaller range.");
+ xbt_assert(range <= decltype(mt19937_gen)::max(),
+ "Overflow in the uniform integer distribution, please use a smaller range.");
+ if (range == decltype(mt19937_gen)::max())
+ return static_cast<int>(mt19937_gen() + min);
+
+ ++range;
+ unsigned long limit = decltype(mt19937_gen)::max() - decltype(mt19937_gen)::max() % range;
unsigned long value;
do {
value = mt19937_gen();
- } while (value >= decltype(mt19937_gen)::max() - decltype(mt19937_gen)::max() % range);
- return value % range + min;
+ } while (value >= limit);
+ return static_cast<int>(value % range + min);
}
double XbtRandom::uniform_real(double min, double max)
do {
numerator = mt19937_gen() - decltype(mt19937_gen)::min();
} while (numerator == divisor);
- return min + (max - min) * numerator / divisor;
+ return min + (max - min) * static_cast<double>(numerator) / divisor;
}
double XbtRandom::exponential(double lambda)
return z0 * sd + mean;
}
-static std::unique_ptr<Random> default_random(new XbtRandom);
+static std::unique_ptr<Random> default_random = std::make_unique<XbtRandom>();
void set_implem_xbt()
{
- default_random.reset(new XbtRandom);
+ default_random = std::make_unique<XbtRandom>();
}
void set_implem_std()
{
- default_random.reset(new StdRandom);
+ default_random = std::make_unique<StdRandom>();
}
void set_mersenne_seed(int seed)