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use std::collections::VecDeque;
use std::time::{Instant, Duration};
use std::ops::AddAssign;
use std::iter::Sum;
use std::default::Default;
pub trait TimeInstant {
fn duration_since(&self, since: Self) -> Duration;
fn forward(&mut self, duration: Duration);
}
pub trait TimeSource {
type Instant: TimeInstant + Copy;
fn now(&self) -> Self::Instant;
}
impl TimeInstant for Instant {
fn duration_since(&self, earlier: Self) -> Duration {
self.duration_since(earlier)
}
fn forward(&mut self, duration: Duration) {
*self += duration;
}
}
#[derive(Debug)]
pub struct RealTimeSource;
impl TimeSource for RealTimeSource {
type Instant = Instant;
fn now(&self) -> Self::Instant {
Instant::now()
}
}
fn dts(duration: Duration) -> f64 {
duration.as_secs() as f64 + duration.subsec_nanos() as f64 * 1e-9
}
fn std(seconds: f64) -> Duration {
assert!(seconds >= 0.0, "RunningAverage negative duration - time going backwards?");
Duration::new(seconds.floor() as u64, ((seconds - seconds.floor()) * 1e-9) as u32)
}
impl TimeInstant for f64 {
fn duration_since(&self, earlier: Self) -> Duration {
std(self - earlier)
}
fn forward(&mut self, duration: Duration) {
*self += dts(duration);
}
}
#[derive(Debug)]
pub struct ManualTimeSource {
now: f64,
}
impl TimeSource for ManualTimeSource {
type Instant = f64;
fn now(&self) -> Self::Instant {
self.now
}
}
impl ManualTimeSource {
pub fn new() -> ManualTimeSource {
ManualTimeSource {
now: 0.0
}
}
pub fn time_shift(&mut self, seconds: f64) {
self.now += seconds;
}
}
#[derive(Debug)]
pub struct Measurement<T> {
value: T,
duration: Duration,
}
use std::fmt;
impl<T> fmt::Display for Measurement<T> where T: Clone + fmt::Display + ToRate, <T as ToRate>::Output: Into<f64> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:.3}", self.rate().into())
}
}
impl<T> Measurement<T> {
pub fn value(&self) -> &T {
&self.value
}
pub fn unwrap(self) -> T {
self.value
}
pub fn rate(&self) -> <T as ToRate>::Output where T: Clone + ToRate {
self.value.clone().to_rate(self.duration)
}
pub fn to_rate(self) -> <T as ToRate>::Output where T: ToRate {
self.value.to_rate(self.duration)
}
}
#[derive(Debug)]
pub struct RunningAverage<V: Default, I: TimeInstant + Copy> {
window: VecDeque<V>,
front: Option<I>,
duration: Duration,
}
impl<V: Default, I: TimeInstant + Copy> Default for RunningAverage<V, I> {
fn default() -> RunningAverage<V, I> {
RunningAverage::new(Duration::from_secs(8))
}
}
impl<V: Default, I: TimeInstant + Copy> RunningAverage<V, I> {
pub fn new(duration: Duration) -> RunningAverage<V, I> {
RunningAverage::with_capacity(duration, 16)
}
pub fn with_capacity(duration: Duration, capacity: usize) -> RunningAverage<V, I> {
assert!(capacity > 0, "RunningAverage capacity cannot be 0");
RunningAverage {
window: (0..capacity).map(|_| V::default()).collect(),
front: None,
duration: duration,
}
}
fn shift(&mut self, now: I) {
let front = self.front.get_or_insert(now);
let slot_duration = self.duration / self.window.len() as u32;
let mut slots_to_go = self.window.len();
while now.duration_since(*front) >= slot_duration {
if slots_to_go == 0 {
let since_front = now.duration_since(*front);
front.forward(since_front);
break;
}
self.window.pop_back();
self.window.push_front(V::default());
front.forward(slot_duration);
slots_to_go -= 1;
}
}
pub fn insert(&mut self, now: I, val: V) where V: AddAssign<V> {
self.shift(now);
*self.window.front_mut().unwrap() += val;
}
pub fn measurement<'i>(&'i mut self, now: I) -> Measurement<V> where V: Sum<&'i V> {
self.shift(now);
Measurement {
value: self.window.iter().sum(),
duration: self.duration,
}
}
}
#[derive(Debug)]
pub struct RealTimeRunningAverage<V: Default, TS: TimeSource = RealTimeSource> {
inner: RunningAverage<V, TS::Instant>,
time_source: TS,
}
impl<V: Default> Default for RealTimeRunningAverage<V, RealTimeSource> {
fn default() -> RealTimeRunningAverage<V, RealTimeSource> {
RealTimeRunningAverage::new(Duration::from_secs(8))
}
}
impl<V: Default> RealTimeRunningAverage<V, RealTimeSource> {
pub fn new(duration: Duration) -> RealTimeRunningAverage<V, RealTimeSource> {
let time_source = RealTimeSource;
RealTimeRunningAverage {
inner: RunningAverage::new(duration),
time_source,
}
}
}
impl<V: Default, TS: TimeSource> RealTimeRunningAverage<V, TS> {
pub fn with_time_source(duration: Duration, capacity: usize, time_source: TS) -> RealTimeRunningAverage<V, TS> {
RealTimeRunningAverage {
inner: RunningAverage::with_capacity(duration, capacity),
time_source,
}
}
pub fn insert(&mut self, val: V) where V: AddAssign<V> {
let now = self.time_source.now();
self.inner.insert(now, val)
}
pub fn measurement<'i>(&'i mut self) -> Measurement<V> where V: Sum<&'i V> {
let now = self.time_source.now();
self.inner.measurement(now)
}
pub fn time_source(&mut self) -> &mut TS {
&mut self.time_source
}
}
pub trait ToRate {
type Output;
fn to_rate(self, duration: Duration) -> Self::Output;
}
impl<T: Into<f64>> ToRate for T {
type Output = f64;
fn to_rate(self, duration: Duration) -> f64 {
let v: f64 = self.into();
v / dts(duration)
}
}
#[cfg(test)]
mod tests {
#[test]
fn const_over_different_capacity() {
use super::*;
for capacity in 1..31 {
let mut tw = RealTimeRunningAverage::with_time_source(Duration::from_secs(4), capacity, ManualTimeSource::new());
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.insert(10);
assert_eq!(tw.measurement().unwrap(), 40, "for capacity {}: {:?}", capacity, tw);
assert_eq!(tw.measurement().to_rate(), 10.0, "for capacity {}: {:?}", capacity, tw);
}
}
#[test]
fn const_half_time_over_different_capacity() {
use super::*;
for capacity in 1..31 {
let mut tw = RealTimeRunningAverage::with_time_source(Duration::from_secs(4), capacity, ManualTimeSource::new());
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.time_source().time_shift(1.0);
assert_eq!(tw.measurement().unwrap(), 20, "for capacity {}: {:?}", capacity, tw);
assert_eq!(tw.measurement().to_rate(), 5.0, "for capacity {}: {:?}", capacity, tw);
}
}
#[test]
fn default_int() {
use super::*;
let mut tw = RealTimeRunningAverage::default();
tw.insert(10);
tw.insert(10);
assert_eq!(tw.measurement().unwrap(), 20, "default: {:?}", tw);
assert_eq!(tw.measurement().to_rate(), 2.5, "default: {:?}", tw);
}
#[test]
fn default_f64() {
use super::*;
let mut tw = RealTimeRunningAverage::default();
tw.insert(10f64);
tw.insert(10.0);
assert_eq!(tw.measurement().unwrap(), 20.0, "default: {:?}", tw);
assert_eq!(tw.measurement().to_rate(), 2.5, "default: {:?}", tw);
}
#[test]
fn long_time_shift() {
use super::*;
let mut tw = RealTimeRunningAverage::with_time_source(Duration::from_secs(4), 16, ManualTimeSource::new());
tw.insert(10);
tw.time_source().time_shift(1_000_000_000.0);
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.insert(10);
tw.time_source().time_shift(1.0);
tw.insert(10);
assert_eq!(tw.measurement().unwrap(), 40, "long: {:?}", tw);
assert_eq!(tw.measurement().to_rate(), 10.0, "long: {:?}", tw);
}
#[test]
fn measurement_display() {
use super::*;
let mut tw = RealTimeRunningAverage::default();
tw.insert(10);
tw.insert(10);
assert_eq!(&format!("{}", tw.measurement()), "2.500");
}
}