rand.c

#include "ruby.h"
#include "numo/narray.h"
#include "SFMT.h"

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <time.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif

static u_int64_t
random_seed(void)
{
    static int n = 0;
    struct timeval tv;

    gettimeofday(&tv, 0);
    return tv.tv_sec ^ tv.tv_usec ^ getpid() ^ n++;
}

static VALUE
nary_s_srand(int argc, VALUE *argv, VALUE obj)
{
    VALUE vseed;
    u_int64_t seed;

    //rb_secure(4);
    if (rb_scan_args(argc, argv, "01", &vseed) == 0) {
        seed = random_seed();
    }
    else {
        seed = NUM2UINT64(vseed);
    }
    init_gen_rand(seed);

    return Qnil;
}

void
Init_nary_rand(void) {
    rb_define_singleton_method(cNArray, "srand", nary_s_srand, -1);
    init_gen_rand(0);
}