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