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[yul-phaser] SimulationRNG: Use a single, shared and seedable generator

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This commit is contained in:
Kamil Śliwak
2020-02-16 02:18:21 +01:00
parent 342a4e5dee
commit db140a667a
3 changed files with 93 additions and 7 deletions
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tools/yulPhaser/SimulationRNG.cpp
+11 -7
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@@ -25,20 +25,24 @@
using namespace solidity;
using namespace solidity::phaser;
thread_local boost::random::mt19937 SimulationRNG::s_generator(SimulationRNG::generateSeed());
uint32_t SimulationRNG::uniformInt(uint32_t _min, uint32_t _max)
{
// TODO: Seed must be configurable
static boost::random::mt19937 generator(time(0));
boost::random::uniform_int_distribution<> distribution(_min, _max);
return distribution(generator);
return distribution(s_generator);
}
uint32_t SimulationRNG::binomialInt(uint32_t _numTrials, double _successProbability)
{
// TODO: Seed must be configurable
static boost::random::mt19937 generator(time(0));
boost::random::binomial_distribution<> distribution(_numTrials, _successProbability);
return distribution(s_generator);
}
return distribution(generator);
uint32_t SimulationRNG::generateSeed()
{
// This is not a secure way to seed the generator but it's good enough for simulation purposes.
// The only thing that matters for us is that the sequence is different on each run and that
// it fits the expected distribution. It does not have to be 100% unpredictable.
return time(0);
}