Rust SystemTime conversion to unixtime in nanoseconds

systemtime_into_unixtime_ns.rs

trait SystemTimeToUnixTime {
    fn unixtime(&self) -> i64;
    fn unixtime_ns(&self) -> i64;
}

impl SystemTimeToUnixTime for std::time::SystemTime {
    fn unixtime(&self) -> i64 {
        match self.duration_since(std::time::SystemTime::UNIX_EPOCH) {
            Ok(n) => n.as_secs().try_into().unwrap_or(i64::MAX), 
            Err(t) => t.duration().as_secs().try_into().map(|t: i64| -t).unwrap_or(i64::MIN),
        }
    }

    fn unixtime_ns(&self) -> i64 {
        match self.duration_since(std::time::SystemTime::UNIX_EPOCH) {
            Ok(n) => n.as_nanos().try_into().unwrap_or(i64::MAX), 
            Err(t) => t.duration().as_nanos().try_into().map(|t: i64| -t).unwrap_or(i64::MIN),
        }
    }
}

fn main() {
    use std::time::{SystemTime, Duration};

    // let now = SystemTime::now();
    let now = SystemTime::UNIX_EPOCH - Duration::from_millis(10543);
    println!("seconds since epoch: {}", now.unixtime_ns() as f64 / 1_000_000_000f64);
}