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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef COMMON_RANDOM_H
#define COMMON_RANDOM_H
#include "common/scummsys.h"
namespace Common {
/**
* @defgroup common_rng RNG
* @ingroup common
*
* @brief Random number generator (RNG) implementation.
*
* @{
*/
class String;
/**
* Xorshift* random number generator. Although it is definitely not suitable for
* cryptographic purposes, it serves our purposes just fine.
*/
class RandomSource {
private:
uint32 _randSeed;
public:
/**
* Construct a new randomness source with the specific @p name.
* The name used must be globally unique, and is used to
* register the randomness source with the active event recorder,
* if any.
*/
RandomSource(const String &name);
/**
* Generates new seed based on the current date/time
*/
static uint32 generateNewSeed();
void setSeed(uint32 seed); /*!< Set the seed used to initialize the RNG. */
uint32 getSeed() const { /*!< Get a random seed that can be used to initialize the RNG. */
return _randSeed;
}
/**
* Generate a random unsigned integer in the interval [0, max].
* @param max The upper bound
* @return A random number in the interval [0, max].
*/
uint getRandomNumber(uint max);
/**
* Generate a random bit, i.e. either 0 or 1.
* Identical to @c getRandomNumber(1), but potentially faster.
* @return A random bit, either 0 or 1.
*/
uint getRandomBit();
/**
* Generate a random unsigned integer in the interval [min, max].
* @param min The lower bound.
* @param max The upper bound.
* @return A random number in the interval [min, max].
*/
uint getRandomNumberRng(uint min, uint max);
/**
* Generates a random signed integer in the interval [min, max].
* @param min the lower bound
* @param max the upper bound
* @return a random number in the interval [min, max]
*/
int getRandomNumberRngSigned(int min, int max);
/**
* Scrambles the seed in order to get a new result.
* Code is shared between getRandomNumber and getRandomBit,
* so it is split off for clarity.
*/
private:
inline void scrambleSeed();
};
/** @} */
} // End of namespace Common
#endif
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