Revision 63d8a43408637eef9a81e05ffd7e6ff3afa51947 authored by Robert B. Gramacy on 20 September 2006, 00:00:00 UTC, committed by Gabor Csardi on 20 September 2006, 00:00:00 UTC
1 parent 622e02d
randomkit.c
/* Random kit 1.3 */
/*
* Copyright (c) 2003-2005, Jean-Sebastien Roy (js@jeannot.org)
*
* The rk_random and rk_seed functions algorithms and the original design of
* the Mersenne Twister RNG:
*
* Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
* All rights reserved.
*
* Original algorithm for the implementation of rk_interval function from
* Richard J. Wagner's implementation of the Mersenne Twister RNG, optimised by
* Magnus Jonsson.
*
* Constants used in the rk_double implementation by Isaku Wada.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/* static char const rcsid[] =
"@(#) $Jeannot: randomkit.c,v 3.28 2005/07/21 22:14:09 js Exp $"; */
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <limits.h>
#include <math.h>
#ifdef _WIN32
/* Windows */
#include <sys/timeb.h>
#ifndef RK_NO_WINCRYPT
/* Windows crypto */
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0400
#endif
#include <windows.h>
#include <wincrypt.h>
#endif
#else
/* Unix */
#include <sys/time.h>
#include <unistd.h>
#endif
#include "randomkit.h"
#ifndef RK_DEV_URANDOM
#define RK_DEV_URANDOM "/dev/urandom"
#endif
#ifndef RK_DEV_RANDOM
#define RK_DEV_RANDOM "/dev/random"
#endif
char *rk_strerror[RK_ERR_MAX] =
{
"no error",
"random device unvavailable"
};
/* static functions */
static unsigned long rk_hash(unsigned long key);
void rk_seed(unsigned long seed, rk_state *state)
{
int pos;
seed &= 0xffffffffUL;
/* Knuth's PRNG as used in the Mersenne Twister reference implementation */
for (pos=0; pos<RK_STATE_LEN; pos++)
{
state->key[pos] = seed;
seed = (1812433253UL * (seed ^ (seed >> 30)) + pos + 1) & 0xffffffffUL;
}
state->pos = RK_STATE_LEN;
state->has_gauss = 0;
}
/* Thomas Wang 32 bits integer hash function */
unsigned long rk_hash(unsigned long key)
{
key += ~(key << 15);
key ^= (key >> 10);
key += (key << 3);
key ^= (key >> 6);
key += ~(key << 11);
key ^= (key >> 16);
return key;
}
rk_error rk_randomseed(rk_state *state)
{
#ifndef _WIN32
struct timeval tv;
#else
struct _timeb tv;
#endif
if(rk_devfill(state->key, sizeof(state->key), 0) == RK_NOERR)
{
state->key[0] |= 0x80000000UL; /* ensures non-zero key */
state->pos = RK_STATE_LEN;
state->has_gauss = 0;
return RK_NOERR;
}
#ifndef _WIN32
gettimeofday(&tv, NULL);
rk_seed(rk_hash(getpid()) ^ rk_hash(tv.tv_sec) ^ rk_hash(tv.tv_usec)
^ rk_hash(clock()), state);
#else
_ftime(&tv);
rk_seed(rk_hash(tv.time) ^ rk_hash(tv.millitm) ^ rk_hash(clock()), state);
#endif
return RK_ENODEV;
}
/* Magic Mersenne Twister constants */
#define N 624
#define M 397
#define MATRIX_A 0x9908b0dfUL
#define UPPER_MASK 0x80000000UL
#define LOWER_MASK 0x7fffffffUL
/* Slightly optimised reference implementation of the Mersenne Twister */
unsigned long rk_random(rk_state *state)
{
unsigned long y;
if (state->pos == RK_STATE_LEN)
{
int i;
for (i=0;i<N-M;i++)
{
y = (state->key[i] & UPPER_MASK) | (state->key[i+1] & LOWER_MASK);
state->key[i] = state->key[i+M] ^ (y>>1) ^ (-(y & 1) & MATRIX_A);
}
for (;i<N-1;i++)
{
y = (state->key[i] & UPPER_MASK) | (state->key[i+1] & LOWER_MASK);
state->key[i] = state->key[i+(M-N)] ^ (y>>1) ^ (-(y & 1) & MATRIX_A);
}
y = (state->key[N-1] & UPPER_MASK) | (state->key[0] & LOWER_MASK);
state->key[N-1] = state->key[M-1] ^ (y>>1) ^ (-(y & 1) & MATRIX_A);
state->pos = 0;
}
y = state->key[state->pos++];
/* Tempering */
y ^= (y >> 11);
y ^= (y << 7) & 0x9d2c5680UL;
y ^= (y << 15) & 0xefc60000UL;
y ^= (y >> 18);
return y;
}
long rk_long(rk_state *state)
{
return rk_ulong(state) >> 1;
}
unsigned long rk_ulong(rk_state *state)
{
#if ULONG_MAX <= 0xffffffffUL
return rk_random(state);
#else
return (rk_random(state) << 32) | (rk_random(state));
#endif
}
unsigned long rk_interval(unsigned long max, rk_state *state)
{
unsigned long mask = max, value;
if (max == 0) return 0;
/* Smallest bit mask >= max */
mask |= mask >> 1;
mask |= mask >> 2;
mask |= mask >> 4;
mask |= mask >> 8;
mask |= mask >> 16;
#if ULONG_MAX > 0xffffffffUL
mask |= mask >> 32;
#endif
/* Search a random value in [0..mask] <= max */
while ((value = (rk_ulong(state) & mask)) > max);
return value;
}
double rk_double(rk_state *state)
{
/* shifts : 67108864 = 0x4000000, 9007199254740992 = 0x20000000000000 */
long a = rk_random(state) >> 5, b = rk_random(state) >> 6;
return (a * 67108864.0 + b) / 9007199254740992.0;
}
void rk_fill(void *buffer, size_t size, rk_state *state)
{
unsigned long r;
unsigned char *buf = buffer;
for (; size >= 4; size -= 4)
{
r = rk_random(state);
*(buf++) = r & 0xFF;
*(buf++) = (r >> 8) & 0xFF;
*(buf++) = (r >> 16) & 0xFF;
*(buf++) = (r >> 24) & 0xFF;
}
if (!size) return;
r = rk_random(state);
for (; size; r >>= 8, size --)
*(buf++) = (unsigned char)(r & 0xFF);
}
rk_error rk_devfill(void *buffer, size_t size, int strong)
{
#ifndef _WIN32
FILE *rfile;
int done;
if (strong)
rfile = fopen(RK_DEV_RANDOM, "rb");
else
rfile = fopen(RK_DEV_URANDOM, "rb");
if (rfile == NULL)
return RK_ENODEV;
done = fread(buffer, size, 1, rfile);
fclose(rfile);
if (done)
return RK_NOERR;
#else
#ifndef RK_NO_WINCRYPT
HCRYPTPROV hCryptProv;
BOOL done;
if (!CryptAcquireContext(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT) || !hCryptProv)
return RK_ENODEV;
done = CryptGenRandom(hCryptProv, size, (unsigned char *)buffer);
CryptReleaseContext(hCryptProv, 0);
if (done)
return RK_NOERR;
#endif
#endif
return RK_ENODEV;
}
rk_error rk_altfill(void *buffer, size_t size, int strong, rk_state *state)
{
rk_error err;
err = rk_devfill(buffer, size, strong);
if (err)
rk_fill(buffer, size, state);
return err;
}
double rk_gauss(rk_state *state)
{
if (state->has_gauss)
{
state->has_gauss = 0;
return state->gauss;
}
else
{
double f, x1, x2, r2;
do
{
x1 = 2.0*rk_double(state) - 1.0;
x2 = 2.0*rk_double(state) - 1.0;
r2 = x1*x1 + x2*x2;
}
while (r2 >= 1.0 || r2 == 0.0);
f = sqrt(-2.0*log(r2)/r2); /* Box-Muller transform */
state->has_gauss = 1;
state->gauss = f*x1; /* Keep for next call */
return f*x2;
}
}
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