uint64_t xorshift64star_uniform( uint64_t range ) {
if (range == 0 || range == 1) { return 0; }
uint64_t cutoff = UINT64_MAX - ( UINT64_MAX % range );
uint64_t result;
while (( result = xorshift64star( )) > cutoff ) ;
return result % range;
}
static void
array_init(void)
{
for (int i = 0; i < ARRAY_SIZE; i++)
array[i] = i;
for (int i = ARRAY_SIZE - 1; i > 0; i--) {
int swap = xorshift64star() % (i + 1);
int tmp = array[i];
array[i] = array[swap];
array[swap] = tmp;
}
}
static int
iter_sample(strm_stream* strm, strm_value data)
{
struct sample_data* d = strm->data;
uint64_t r;
if (d->i < d->len) {
d->samples[d->i++] = data;
return STRM_OK;
}
xorshift64init();
r = xorshift64star()%(d->i);
if (r < d->len) {
d->samples[r] = data;
}
d->i++;
return STRM_OK;
}
int main()
{
int k;
uint64_t s[16];
initxorshift64star(0x1234567887654321);
printf("Seed:\n");
for (k = 0; k < 16; ++k) {
s[k] = xorshift64star();
printf("%2d %llu\n", k, s[k]);
}
initxorshift1024star(s);
printf("Outputs:\n");
for (k = 0; k < 32; ++k) {
printf("%2d %llu\n", k, xorshift1024star());
}
return 0;
}
