#include "rng.h"

#include <assert.h>
#include <sys/time.h>

static uint32_t state;

void rng_init()
{
	struct timeval tv;
	const int res = gettimeofday(&tv, nullptr);
	assert(res == 0);
	state = tv.tv_usec;
}

uint32_t rng_uint32()
{
	state ^= state << 13;
	state ^= state >> 17;
	state ^= state << 5;
	return state;
}

float rng_canon()
{
	return (float)rng_uint32() / UINT32_MAX;
}

float rng_plusminus()
{
	return 2.0 * rng_canon() - 1.0;
}