rrand.c

此文件利用最新的加斯拉奇算法制造随机种子给随机数的数理统计达到最优化

/*\
 * RRAND RNG - Ruptor's Fast True Random Number Generator, v1.0
 * http://cryptolib.com/crypto/rrand
 * Copyright (c) 1992-2007 Marcos el Ruptor
\*/

#ifndef _CRT_SECURE_NO_DEPRECATE
#define _CRT_SECURE_NO_DEPRECATE 1
#endif

#include <string.h>
#include <stdio.h>
#include "rrand.h"

#if (defined(_MSC_VER)||defined(__INTEL_COMPILER))
#pragma intrinsic (_lrotl)
#else
#define _lrotl(x,n) ((((ulong)(x))<<(n&31))|(((ulong)(x))>>((0-(n))&31)))
#endif

#define RUPT(m,n,p,k) (rr->pool[n] += ((_lrotl (rr->pool[m], 13) ^ _lrotl (rr->pool[p], 3)) + 0x55555555) ^ (ulong) k)

#define rrand_reseed(rr,r,seed) \
{ \
    int i, n; \
    for (i = 0; i < r; i++) \
    { \
        RUPT (RRAND_SIZE-1, 0, 1, clock_counter ()); \
        for (n = RRAND_SIZE-2; n; n--) RUPT (n-1, n, n+1, seed); \
        RUPT (RRAND_SIZE-2, RRAND_SIZE-1, 0, clock_counter ()); \
    } \
}

void rrand_init (rrand_state * const rr) { rrand_reseed (rr, (1024/RRAND_SIZE)|3, clock_counter()); }

#define rr ((rrand_state *) vr)

ulong rrand (void * const vr)
{
    uint o = rr->offset;

    if (o >= RRAND_SIZE/2)
    {
        rrand_reseed (rr, 1, clock_counter ()); // replace clock_counter with a constant to improve speed
        rr->offset = o = 0;
    }
    RUPT (o, o+1, o+2, 0xAE515BAD);
    rr->offset = ++o;
    return (rr->pool[o+RRAND_SIZE/2] ^ rr->pool[o]);
}

#undef rr

#ifdef RAND_TEST

#include <time.h>

static ulong buf[65536];

int main (int argc, char *argv[])
{
    FILE *f;
    time_t t;
    int i, j, k;
    rrand_state rr;
    ulong q, v = -1;
    
    if (argc < 2)
    {
        fprintf (stderr, "usage: %s <output filename>\n", argv[0]);
        return 1;
    }
    if ((f = fopen (argv[1], "wb+")) == NULL)
    {
        fprintf (stderr, "failed to open '%s' for writing.\n", argv[1]);
        return 1;
    }
    rrand_init (&rr);
    t = time (NULL);
    for (i = 0, k = 5120/sizeof(ulong); i < k; i++)
    {
        q = (ulong) clock_counter ();
        for (j = 0; j < 65536; j++) buf[j] = rrand (&rr);
		q = (ulong) clock_counter () - q;
		v += q;
        fwrite (buf, sizeof(buf), 1, f);
        printf ("\rGenerating 320Mb of data in file '%s'... %04.1f%% done... [%4ld clocks per byte]", argv[1], (100*(float)(i+1))/k, q/(65536*sizeof(ulong)));
        fflush (stdout);
    }
    if (t == time (NULL)) t--;
    printf ("\rGenerating 320Mb of data in file '%s'... done (%ld bytes/sec) [%4ld clocks per byte]\n", argv[1], (65536*5120/sizeof(ulong))/(time(NULL)-t), v /= (5120*65536));
    fclose (f);
    return 0;
}
#endif