Linear congruential generator - Park–Miller

park_miller.rs

pub struct Random {
    pub state: u32,
}

impl Random {
    pub fn new() -> Random {
        Random { state: Random::new_seed() }
    }

    fn new_seed() -> u32 {
        std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap().as_nanos() as u32
    }

    pub fn update_seed(&mut self) {
        self.state = Random::new_seed();
    }

    // Park–Miller RNG
    pub fn shuffle(&mut self) {
        let a: u32 = 16807;
        let c: u32 = 0;

        for _ in 0..5 {
            self.state = self.state.wrapping_mul(a).wrapping_add(c);
        }
    }
}