RetroShare/libbitdht/src/util/bdrandom.h
2018-05-21 18:23:52 +02:00

73 lines
2.9 KiB
C++

/*******************************************************************************
* util/bdrandom.h *
* *
* BitDHT: An Flexible DHT library. *
* *
* Copyright (C) 2010 Cyril Soler <csoler@users.sourceforge.net> *
* *
* This program is free software: you can redistribute it and/or modify *
* it under the terms of the GNU Affero 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 Affero General Public License for more details. *
* *
* You should have received a copy of the GNU Affero General Public License *
* along with this program. If not, see <https://www.gnu.org/licenses/>. *
* *
*******************************************************************************/
#ifndef BITDHT_UTILS_BDRANDOM_H
#define BITDHT_UTILS_BDRANDOM_H
/* This Source Code is basically a direct copy of libretroshare's RsRandom.
* the function names have just been renamed. drbob
*/
// bdRandom contains a random number generator that is
// - thread safe
// - system independant
// - fast
// - NOT CRYPTOGRAPHICALLY SAFE
// - DO NOT USE FOR ANYTHING REQUIRING STRONG UNPREDICTABLE RANDOMNESS
//
// The implementation is adapted from the Mersenne Twister page of Wikipedia.
//
// http://en.wikipedia.org/wiki/Mersenne_twister
// FIXME(ben): MT is not cryptographically safe.
#include <vector>
#include "util/bdthreads.h"
class bdRandom
{
public:
static uint32_t random_u32() ;
static uint64_t random_u64() ;
static float random_f32() ;
static double random_f64() ;
static bool seed(uint32_t s) ;
static std::string random_alphaNumericString(uint32_t length) ;
private:
static bdMutex rndMtx ;
static const uint32_t N = 624;
static const uint32_t M = 397;
static const uint32_t MATRIX_A = 0x9908b0dfUL;
static const uint32_t UMASK = 0x80000000UL;
static const uint32_t LMASK = 0x7fffffffUL;
static void locked_next_state() ;
static uint32_t index ;
static std::vector<uint32_t> MT ;
};
#endif