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use uuid::Uuid;
pub struct HyperId {
uuid: Uuid,
c: u8,
}
impl HyperId {
pub fn new() -> Self {
let uuid = Uuid::new_v4();
let c: u8 = 0;
Self { uuid, c }
}
pub fn get(&self) -> Id {
Id {
uuid_as_128: self.uuid.as_u128(),
c: self.c,
}
}
pub fn generate(&mut self) -> Id {
self.c = self.c.checked_add(1).unwrap_or(0);
if self.c == 0 {
self.uuid = Uuid::new_v4();
}
Id {
uuid_as_128: self.uuid.as_u128(),
c: self.c,
}
}
}
impl Default for HyperId {
fn default() -> Self {
Self::new()
}
}
#[derive(PartialEq, Debug)]
pub struct Id {
uuid_as_128: u128,
c: u8,
}
impl Id {
pub fn to_url_safe(&self) -> String {
format!("{}-{}", self.uuid_as_128, self.c)
}
pub fn from_url_safe(s: String) -> Result<Id, ParseIdError> {
let mut split = s.split('-');
let uuid_as_128 = split
.next()
.ok_or(ParseIdError::NoBaseFound)
.and_then(|uuid_as_128| {
uuid_as_128
.parse::<u128>()
.map_err(|_| ParseIdError::NoBaseFound)
});
let c = split
.next()
.ok_or(ParseIdError::NoCounterFound)
.and_then(|c| c.parse::<u8>().map_err(|_| ParseIdError::NoCounterFound));
match (uuid_as_128, c) {
(Ok(uuid_as_128), Ok(c)) => Ok(Id { uuid_as_128, c }),
(Err(err), _) | (_, Err(err)) => Err(err),
}
}
}
#[derive(Debug)]
pub enum ParseIdError {
NoBaseFound,
NoCounterFound,
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn starts_from_zero() {
let hyperid = HyperId::default();
assert_eq!(hyperid.c, 0);
}
#[test]
fn get_return_equal_id() {
let hyperid = HyperId::default();
assert_eq!(hyperid.get(), hyperid.get());
}
#[test]
fn generate_change_internal_state() {
let mut hyperid = HyperId::default();
let c = hyperid.c;
hyperid.generate();
assert_ne!(hyperid.c, c);
}
#[test]
fn generate_returns_different_id() {
let mut hyperid = HyperId::default();
let previous_id = hyperid.get();
let next_id = hyperid.generate();
assert_ne!(previous_id, next_id);
}
#[test]
fn on_255_generate_a_new_base() {
let mut hyperid = HyperId::default();
let base = hyperid.uuid;
for _ in 0..255 {
hyperid.generate();
}
let new_base = hyperid.uuid;
assert_eq!(base, new_base);
hyperid.generate();
let new_base = hyperid.uuid;
assert_ne!(base, new_base);
}
#[test]
fn different_instances_have_different_base() {
let hyperid1 = HyperId::default();
let hyperid2 = HyperId::default();
assert_ne!(hyperid1.uuid, hyperid2.uuid);
}
}