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// Used to keep track of time.
#[derive(Debug, Default, Clone, Copy)]
pub struct TimeTracker {
now_sec_f64: f64,
}
/// Maximum number of seconds we can track. This is related
/// to the limit of a mantissa in 64-bit IEEE numbers, which
/// is about 10^15. Since we count in msec, we have to divide
/// to take away 3 digits. This is still several centuries.
pub const TIME_TRACKER_MAX_SEC: f64 = 1e12;
impl TimeTracker {
/// Create a time tracker.
///
/// # Examples
///
/// ```
/// use babalcore::*;
///
/// let _tt = TimeTracker::new();
/// ```
pub fn new() -> TimeTracker {
TimeTracker::default()
}
/// Add time to the time tracker. This is typically something
/// you'd call each time there's a process(delta).
///
/// # Examples
///
/// ```
/// use babalcore::*;
///
/// let mut tt = TimeTracker::new();
/// tt.add(0.01);
/// assert_eq!(0.01, tt.now_sec());
/// ```
pub fn add(&mut self, delta: f64) {
self.now_sec_f64 += delta;
if self.now_sec_f64 < 0.0 || self.now_sec_f64 >= TIME_TRACKER_MAX_SEC {
self.now_sec_f64 = 0.0;
}
}
/// Get the number of seconds since start of time.
///
/// # Examples
///
/// ```
/// use babalcore::*;
///
/// let mut tt = TimeTracker::new();
/// assert_eq!(0.0, tt.now_sec());
/// tt.add(0.003);
/// assert_eq!(0.003, tt.now_sec());
/// ```
pub fn now_sec(&self) -> f64 {
self.now_sec_f64
}
/// Get the number of milliseconds since start of time.
///
/// # Examples
///
/// ```
/// use babalcore::*;
///
/// let mut tt = TimeTracker::new();
/// assert_eq!(0, tt.now_msec());
/// tt.add(0.003);
/// assert_eq!(3, tt.now_msec());
/// ```
pub fn now_msec(&self) -> i64 {
(self.now_sec_f64 * 1000.0) as i64
}
}
impl std::fmt::Display for TimeTracker {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let now_msec = self.now_msec();
write!(f, "{}.{:03}", now_msec / 1000, now_msec % 1000)
}
}
#[cfg(test)]
mod tests {
use crate::*;
#[test]
fn test_fmt() {
let mut tt = TimeTracker::new();
tt.add(2.0);
tt.add(0.05);
assert_eq!("2.050", format!("{}", tt));
}
}