random.c

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#ifndef _WIN32
#include <stdio.h>
#include <unistd.h>
#endif
#define _CRT_RAND_S // request rand_s (Win)
#include <stdlib.h>
 
#include "random.h"
#include "tv.h"
 
void
ug_rand_init(void)
{
#ifndef _WIN32
        unsigned seed =
            (getpid() * 42) ^ (unsigned) get_time_in_ns() ^ (unsigned) clock();
        FILE *dev_r = fopen("/dev/random", "rb");
        if (dev_r != NULL) {
                unsigned seed_dev_r = 0;
                if (fread(&seed_dev_r, sizeof seed_dev_r, 1, dev_r) == 1) {
                        seed ^= seed_dev_r;
                }
                fclose(dev_r);
        }
        srandom(seed);
#endif
}
 
uint32_t
ug_rand(void)
{
#ifdef _WIN32
        uint32_t ret = 0;
        rand_s(&ret);
#else
        uint32_t ret = (uint32_t) random() << 1;
        ret |= random() & 0x1;
#endif
        return ret;
}
 
double
ug_drand()
{
        return ug_rand() / (UINT32_MAX + 1.0);
}