use rand::distributions::{Distribution, Uniform};
use rand::rngs::StdRng;
use rand::SeedableRng;
use crate::traits::OrDistElement;
pub trait Shuffle: Sized {
fn shuffle(&self) -> Self {
self.shuffle_seed(gen_seed_u32())
}
fn shuffle_into(&mut self) -> Self {
self.shuffle_seed_into(gen_seed_u32())
}
fn shuffle_inplace(&mut self) {
self.shuffle_seed_inplace(gen_seed_u32())
}
fn shuffle_seed(&self, random_seed: u32) -> Self;
fn shuffle_seed_into(&mut self, random_seed: u32) -> Self;
fn shuffle_seed_inplace(&mut self, random_seed: u32);
}
impl<T: OrDistElement> Shuffle for Vec<T> {
fn shuffle_seed(&self, random_seed: u32) -> Self {
let mut v = self.clone();
v.shuffle_seed_inplace(random_seed);
v
}
fn shuffle_seed_into(&mut self, random_seed: u32) -> Self {
self.shuffle_seed_inplace(random_seed);
self.clone()
}
fn shuffle_seed_inplace(&mut self, random_seed: u32) {
shuffle(self, random_seed);
}
}
pub fn shuffle<T: OrDistElement>(v: &mut [T], random_seed: u32) {
let mut v2 = v.to_owned();
let n = v2.len();
let mut rng = StdRng::from_seed(seed_from_u32(random_seed));
for i in 0..n {
let ud = Uniform::new(0, n - i);
let e = v2.remove(ud.sample(&mut rng));
v[i] = e;
}
}
pub fn gen_seed_u32() -> u32 {
let ud = Uniform::new(u32::MIN, u32::MAX);
ud.sample(&mut rand::thread_rng())
}
pub fn seed_from_u32(seed: u32) -> [u8; 32] {
let mut v = [0; 32];
for i in 0..32 {
v[i] = (seed >> i & 1) as u8;
}
v
}