#queue #ttl #fps-counter

ttl-queue

A queue that drops its content after a given amount of time

2 unstable releases

0.2.0 Aug 2, 2023
0.1.0 Aug 2, 2023

#1247 in Data structures

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149 downloads per month

EUPL-1.2

17KB
334 lines

Timed Queue

A queue that drops its content after a given amount of time.

Example

To implement an FPS counter, you could use the following technique:

use std::thread;
use std::time::Duration;
use ttl_queue::TtlQueue;

fn main() {
    let mut fps_counter = TtlQueue::new(Duration::from_secs_f64(1.0));

    for i in 0..100 {
        // Register a new frame and return the number of frames observed
        // within the last second.
        let fps = fps_counter.refresh_and_push_back(());
        debug_assert!(fps >= 1);

        // Sleep 10 ms to achieve a ~100 Hz frequency.
        thread::sleep(Duration::from_millis(10));
    }

    let fps = fps_counter.refresh();
    debug_assert!(fps >= 95 && fps <= 105);
}

lib.rs:

Timed Queue

A queue that drops its content after a given amount of time.

Crate Features

  • vecdeque - Uses a VecDeque as the underlying data structure. Enabled by default.
  • doublestack - Uses two stacks (Vec) as the underlying data structure. Mutually exclusive with vecdeque.
  • tokio - Uses tokio::time::Instant instead of std::time::Instant.

Example

To implement an FPS counter, you could use the following technique:

let mut fps_counter = TtlQueue::new(Duration::from_secs_f64(1.0));

for i in 0..=50 {
    // Register a new frame and return the number of frames observed
    // within the last second.
    let fps = fps_counter.refresh_and_push_back(());
    debug_assert!(fps >= 1);

    // Sleep ~20 ms to achieve a ~50 Hz frequency.
    thread::sleep(Duration::from_millis(19));
}

let fps = fps_counter.refresh();
debug_assert!(fps >= 45 && fps <= 55);

let delta = fps_counter.avg_delta();
debug_assert!(delta >= Duration::from_millis(19) && delta <= Duration::from_millis(21));

Dependencies

~0–1.1MB
~19K SLoC