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/*
* 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 <vstd/RNG.h>
typedef std::mt19937 TGenerator;
typedef std::uniform_int_distribution<int> TIntDist;
typedef std::uniform_int_distribution<int64_t> TInt64Dist;
typedef std::uniform_real_distribution<double> TRealDist;
typedef std::function<int()> TRandI;
/// 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 standard random API. An instance of this RNG is not thread safe.
class DLL_LINKAGE CRandomGenerator : public vstd::RNG, boost::noncopyable
{
public:
/// Seeds the generator by default with the product of the current time in milliseconds and the
/// current thread ID.
CRandomGenerator();
void setSeed(int seed);
/// Resets the seed to the product of the current time in milliseconds and the
/// current thread ID.
void resetSeed();
/// Generate several integer numbers within the same range.
/// e.g.: auto a = gen.getIntRange(0,10); a(); a(); a();
/// requires: lower <= upper
TRandI getIntRange(int lower, int upper);
vstd::TRandI64 getInt64Range(int64_t lower, int64_t upper) override;
/// Generates an integer between 0 and upper.
/// requires: 0 <= upper
int nextInt(int upper);
/// requires: lower <= upper
int nextInt(int lower, int upper);
/// Generates an integer between 0 and the maximum value it can hold.
int nextInt();
/// Generate several double/real numbers within the same range.
/// e.g.: auto a = gen.getDoubleRange(4.5,10.2); a(); a(); a();
/// requires: lower <= upper
vstd::TRand getDoubleRange(double lower, double upper) override;
/// Generates a double between 0 and upper.
/// requires: 0 <= upper
double nextDouble(double upper);
/// requires: lower <= upper
double nextDouble(double lower, double upper);
/// Generates a double between 0.0 and 1.0.
double nextDouble();
/// Gets a globally accessible RNG which will be constructed once per thread. For the
/// seed a combination of the thread ID and current time in milliseconds will be used.
static CRandomGenerator & getDefault();
/// Provide method so that this RNG can be used with legacy std:: API
TGenerator & getStdGenerator();
private:
TGenerator rand;
static boost::thread_specific_ptr<CRandomGenerator> defaultRand;
public:
template <typename Handler>
void serialize(Handler & h, const int version)
{
if(h.saving)
{
std::ostringstream stream;
stream << rand;
std::string str = stream.str();
h & str;
}
else
{
std::string str;
h & str;
std::istringstream stream(str);
stream >> rand;
}
}
};
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