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vcmi/lib/CRandomGenerator.h
2013-01-08 18:32:47 +00:00

135 lines
3.3 KiB
C++

/*
* CRandomGenerator.h, part of VCMI engine
*
* Authors: listed in file AUTHORS in main folder
*
* License: GNU General Public License v2.0 or later
* Full text of license available in license.txt file, in main folder
*
*/
#pragma once
#include <boost/version.hpp>
#include <boost/random/mersenne_twister.hpp>
#if BOOST_VERSION >= 104700
#include <boost/random/uniform_int_distribution.hpp>
#include <boost/random/uniform_real_distribution.hpp>
#else
#include <boost/random/uniform_int.hpp>
#include <boost/random/uniform_real.hpp>
#endif
#include <boost/random/variate_generator.hpp>
typedef boost::mt19937 TGenerator;
#if BOOST_VERSION >= 104700
typedef boost::random::uniform_int_distribution<int> TIntDist;
typedef boost::random::uniform_real_distribution<double> TRealDist;
#else
typedef boost::uniform_int<int> TIntDist;
typedef boost::uniform_real<double> TRealDist;
#endif
typedef boost::variate_generator<TGenerator &, TIntDist> TRandI;
typedef boost::variate_generator<TGenerator &, TRealDist> TRand;
/**
* The random generator randomly generates integers and real numbers("doubles") between
* a given range. This is a header only class and mainly a wrapper for
* convenient usage of the boost random API.
*/
class CRandomGenerator
{
public:
/**
* Constructor. Seeds the generator with the current time by default.
*/
CRandomGenerator()
{
gen.seed(std::time(nullptr));
}
/**
* Seeds the generator with the given value.
*
* @param value the random seed
*/
void seed(int value)
{
gen.seed(value);
}
/**
* Gets a generator which generates integers in the given range.
*
* Example how to use:
* @code
* TRandI rand = getRangeI(0, 10);
* int a = rand(); // with the operator() the next value can be obtained
* int b = rand(); // you can generate more values
* @endcode
*
* @param lower the lower boundary
* @param upper the upper boundary
* @return the generator which can be used to generate integer numbers
*/
TRandI getRangeI(int lower, int upper)
{
TIntDist range(lower, upper);
return TRandI(gen, range);
}
/**
* Gets a integer in the given range. In comparison to getRangeI it's
* a convenient method if you want to generate only one value in a given
* range.
*
* @param lower the lower boundary
* @param upper the upper boundary
* @return the generated integer
*/
int getInteger(int lower, int upper)
{
return getRangeI(lower, upper)();
}
/**
* Gets a generator which generates doubles in the given range.
*
* Example how to use:
* @code
* TRand rand = getRange(23.56, 32.10);
* double a = rand(); // with the operator() the next value can be obtained
* double b = rand(); // you can generate more values
* @endcode
*
* @param lower the lower boundary
* @param upper the upper boundary
* @return the generated double
*/
TRand getRange(double lower, double upper)
{
TRealDist range(lower, upper);
return TRand(gen, range);
}
/**
* Gets a double in the given range. In comparison to getRange it's
* a convenient method if you want to generate only one value in a given
* range.
*
* @param lower the lower boundary
* @param upper the upper boundary
* @return the generated double
*/
double getDouble(double lower, double upper)
{
return getRange(lower, upper)();
}
private:
/** The actual boost random generator. */
TGenerator gen;
};