rust-algorithms 0.1.0

use std::time::{SystemTime,UNIX_EPOCH};
use std::sync::Mutex;

pub struct SnowflakeWorker {
    last: Mutex<u64>,
    datacenter_id: u8,
    worker_id: u8,
    sequence_id: u16,
}

impl SnowflakeWorker {
     fn now() -> u64 {
         let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
         now.as_millis() as u64
     }

     pub fn gen(&mut self) -> u64 {
        let mut last = self.last.lock().unwrap();
        let now = SnowflakeWorker::now();
        if *last == now {
            self.sequence_id += 1;
        } else if *last < now {
            *last = now;
            self.sequence_id = 0;
        }
        SnowflakeWorker::format(&last, &self.datacenter_id, &self.worker_id, &self.sequence_id)
    }

    fn format(last: &u64, datacenter_id: &u8, worker_id: &u8, sequence_id: &u16) -> u64 {
        last << 22 | (datacenter_id.clone() as u64) << 17 | (worker_id.clone() as u64) << 12 | sequence_id.clone() as u64
    }

    pub fn new(datacenter_id: u8, worker_id: u8) -> SnowflakeWorker {
        SnowflakeWorker { last: Mutex::new(0), datacenter_id: datacenter_id, worker_id: worker_id, sequence_id: 0 }
    }
}