eqemu-server/common/random.h

#ifndef __random_h__
#define __random_h__

#include <random>
#include <utility>

/* This uses mt19937 seeded with the std::random_device
 * The idea is to have this be included as a member of another class
 * so mocking out for testing is easier
 * If you need to reseed random.Reseed()
 * Eventually this should be derived from an abstract base class
 */

namespace EQEmu {
	class Random {
	public:
		// AKA old MakeRandomInt
		const int Int(int low, int high)
		{
			if (low > high)
				std::swap(low, high);
			return std::uniform_int_distribution<int>(low, high)(m_gen); // [low, high]
		}

		// AKA old MakeRandomFloat
		const double Real(double low, double high)
		{
			if (low > high)
				std::swap(low, high);
			return std::uniform_real_distribution<double>(low, high)(m_gen); // [low, high)
		}

		// example Roll(50) would have a 50% success rate
		// Roll(100) 100%, etc
		// valid values 0-100 (well, higher works too but ...)
		const bool Roll(const int required)
		{
			return Int(0, 99) < required;
		}

		// valid values 0.0 - 1.0
		const bool Roll(const double required)
		{
			return Real(0.0, 1.0) <= required;
		}

		void Reseed()
		{
			// We could do the seed_seq thing here too if we need better seeding
			// but that is mostly overkill for us, so just seed once
			std::random_device rd;
			m_gen.seed(rd());
		}

		Random()
		{
			Reseed();
		}

	private:
		std::mt19937 m_gen;
	};
}


#endif /* !__random_h__ */