RetroShare/libbitdht/src/util/bdrandom.cc
2015-10-20 20:32:44 +03:00

100 lines
2.2 KiB
C++

#include <stdlib.h>
#include <string>
#include <unistd.h>
#include <time.h>
#include "util/bdrandom.h"
uint32_t bdRandom::index = 0 ;
std::vector<uint32_t> bdRandom::MT(bdRandom::N,0u) ;
bdMutex bdRandom::rndMtx ;
#if (defined(_WIN32) || defined(__MINGW32__)) && !defined(WIN_PTHREADS_H)
static bool auto_seed = bdRandom::seed( (time(NULL) + ((uint32_t) pthread_self().p)*0x1293fe)^0x18e34a12 ) ;
#else
#ifdef __APPLE__
static bool auto_seed = bdRandom::seed( (time(NULL) + pthread_mach_thread_np(pthread_self())*0x1293fe + (getpid()^0x113ef76b))^0x18e34a12 ) ;
#elif defined(__FreeBSD__) || (__HAIKU__)
// since this is completely insecure anyway, just kludge for now
static bool auto_seed = bdRandom::seed(time(NULL));
#elif defined(__OpenBSD__)
static bool auto_seed = bdRandom::seed(arc4random());
#else
static bool auto_seed = bdRandom::seed( (time(NULL) + pthread_self()*0x1293fe + (getpid()^0x113ef76b))^0x18e34a12 ) ;
#endif
#endif
bool bdRandom::seed(uint32_t s)
{
bdStackMutex mtx(rndMtx) ;
MT.resize(N,0) ; // because MT might not be already resized
uint32_t j ;
MT[0]= s & 0xffffffffUL;
for (j=1; j<N; j++)
MT[j] = (1812433253UL * (MT[j-1] ^ (MT[j-1] >> 30)) + j) & 0xffffffffUL ;
return true ;
}
void bdRandom::locked_next_state()
{
for(uint32_t i=0;i<N;++i)
{
uint32_t y = ((MT[i]) & UMASK) | ((MT[(i+1)%(int)N]) & LMASK) ;
MT[i] = MT[(i + M) % (int)N] ^ (y >> 1) ;
if((y & 1) == 1)
MT[i] = MT[i] ^ 0x9908b0df ;
}
index = 0 ;
}
uint32_t bdRandom::random_u32()
{
uint32_t y;
{
bdStackMutex mtx(rndMtx) ;
y = MT[index++] ;
if(index == N)
locked_next_state();
}
// Tempering
y ^= (y >> 11);
y ^= (y << 7 ) & 0x9d2c5680UL;
y ^= (y << 15) & 0xefc60000UL;
y ^= (y >> 18);
return y;
}
uint64_t bdRandom::random_u64()
{
return ((uint64_t)random_u32() << 32ul) + random_u32() ;
}
float bdRandom::random_f32()
{
return random_u32() / (float)(~(uint32_t)0) ;
}
double bdRandom::random_f64()
{
return random_u64() / (double)(~(uint64_t)0) ;
}
std::string bdRandom::random_alphaNumericString(uint32_t len)
{
std::string s = "" ;
for(uint32_t i=0;i<len;++i)
s += (char)( (random_u32()%94) + 33) ;
return s ;
}