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use rand_core;
use rand_core::le::read_u64_into;
use rand_core::impls::fill_bytes_via_next;
use rand_core::{RngCore, SeedableRng};
#[allow(missing_copy_implementations)]
#[derive(Debug, Clone)]
#[cfg_attr(feature="serde1", derive(Serialize, Deserialize))]
pub struct Xoroshiro128StarStar {
s0: u64,
s1: u64,
}
impl Xoroshiro128StarStar {
pub fn jump(&mut self) {
impl_jump!(u64, self, [0xdf900294d8f554a5, 0x170865df4b3201fc]);
}
pub fn long_jump(&mut self) {
impl_jump!(u64, self, [0xd2a98b26625eee7b, 0xdddf9b1090aa7ac1]);
}
}
impl RngCore for Xoroshiro128StarStar {
#[inline]
fn next_u32(&mut self) -> u32 {
self.next_u64() as u32
}
#[inline]
fn next_u64(&mut self) -> u64 {
let r = starstar_u64!(self.s0);
impl_xoroshiro_u64!(self);
r
}
#[inline]
fn fill_bytes(&mut self, dest: &mut [u8]) {
fill_bytes_via_next(self, dest);
}
#[inline]
fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand_core::Error> {
self.fill_bytes(dest);
Ok(())
}
}
impl SeedableRng for Xoroshiro128StarStar {
type Seed = [u8; 16];
fn from_seed(seed: [u8; 16]) -> Xoroshiro128StarStar {
deal_with_zero_seed!(seed, Self);
let mut s = [0; 2];
read_u64_into(&seed, &mut s);
Xoroshiro128StarStar {
s0: s[0],
s1: s[1],
}
}
fn seed_from_u64(seed: u64) -> Xoroshiro128StarStar {
from_splitmix!(seed)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn reference() {
let mut rng = Xoroshiro128StarStar::from_seed(
[1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0]);
let expected = [
5760, 97769243520, 9706862127477703552, 9223447511460779954,
8358291023205304566, 15695619998649302768, 8517900938696309774,
16586480348202605369, 6959129367028440372, 16822147227405758281,
];
for &e in &expected {
assert_eq!(rng.next_u64(), e);
}
}
}