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//! Delay stream. Good for syncing up streams.
use log::debug;
use crate::block::{Block, BlockRet};
use crate::stream::{ReadStream, WriteStream};
use crate::{Result, Sample};
/// Delay stream. Good for syncing up streams.
#[derive(rustradio_macros::Block)]
#[rustradio(crate)]
pub struct Delay<T: Sample> {
delay: usize,
current_delay: usize,
skip: usize,
#[rustradio(in)]
src: ReadStream<T>,
#[rustradio(out)]
dst: WriteStream<T>,
}
impl<T: Sample> Delay<T> {
/// Create new Delay block.
#[must_use]
pub fn new(src: ReadStream<T>, delay: usize) -> (Self, ReadStream<T>) {
let (dst, dr) = crate::stream::new_stream();
(
Self {
src,
dst,
delay,
current_delay: delay,
skip: 0,
},
dr,
)
}
/// Change the delay.
pub fn set_delay(&mut self, delay: usize) {
if delay > self.delay {
self.current_delay = delay - self.delay;
} else {
let cdskip = std::cmp::min(self.current_delay, delay);
self.current_delay -= cdskip;
self.skip = (self.delay - delay) - cdskip;
}
self.delay = delay;
}
}
impl<T: Sample> Block for Delay<T> {
fn work(&mut self) -> Result<BlockRet<'_>> {
{
let o = self.dst.write_buf()?;
if o.is_empty() {
return Ok(BlockRet::Again);
}
}
if self.current_delay > 0 {
let mut o = self.dst.write_buf()?;
let n = std::cmp::min(self.current_delay, o.len());
if n == 0 {
return Ok(BlockRet::WaitForStream(&self.src, 1));
}
o.slice()[..n].fill(T::default());
o.produce(n, &[]);
self.current_delay -= n;
}
{
let (input, _tags) = self.src.read_buf()?;
let a = input.len();
let n = std::cmp::min(a, self.skip);
if n == 0 && a == 0 {
return Ok(BlockRet::WaitForStream(&self.src, 1));
}
input.consume(n);
debug!("Delay: skipped {n}");
self.skip -= n;
}
let mut o = self.dst.write_buf()?;
let (input, tags) = self.src.read_buf()?;
let n = std::cmp::min(input.len(), o.len());
o.fill_from_slice(input.slice());
o.produce(n, &tags);
input.consume(n);
Ok(BlockRet::Again)
}
}
#[cfg(test)]
mod tests {
use super::*;
// TODO: test tag propagation.
#[test]
fn delay_zero() -> Result<()> {
let s = ReadStream::from_slice(&[1.0f32, 2.0, 3.0]);
let (mut delay, o) = Delay::new(s, 0);
delay.work()?;
let (res, _) = o.read_buf()?;
assert_eq!(res.slice(), vec![1.0f32, 2.0, 3.0]);
Ok(())
}
#[test]
fn delay_one() -> Result<()> {
let s = ReadStream::from_slice(&[1.0f32, 2.0, 3.0]);
let (mut delay, o) = Delay::new(s, 1);
delay.work()?;
let (res, _) = o.read_buf()?;
assert_eq!(res.slice(), vec![0.0f32, 1.0, 2.0, 3.0]);
Ok(())
}
#[test]
fn delay_change() -> Result<()> {
let s = ReadStream::from_slice(&[1u32, 2]);
let (mut delay, o) = Delay::new(s, 1);
delay.work()?;
{
let (res, _) = o.read_buf()?;
assert_eq!(res.slice(), vec![0, 1, 2]);
}
// TODO: fix
/*
// 3,4 => 0,3,4
{
let mut b = s.write_buf()?;
b.fill_from_slice(&[3, 4]);
b.produce(2, &[]);
}
delay.set_delay(2);
delay.work()?;
{
let (res, _) = o.read_buf()?;
assert_eq!(res.slice(), vec![0, 1, 2, 0, 3, 4]);
}
// 5,6 => 0,3,4
{
let mut b = s.write_buf()?;
b.fill_from_slice(&[5, 6]);
b.produce(2, &[]);
}
delay.set_delay(0);
delay.work()?;
{
let (res, _) = o.read_buf()?;
assert_eq!(res.slice(), vec![0, 1, 2, 0, 3, 4]);
}
// 7 => 7
{
let mut b = s.write_buf()?;
b.slice()[0] = 7;
b.produce(1, &[]);
}
delay.set_delay(0);
delay.work()?;
{
let (res, _) = o.read_buf()?;
assert_eq!(res.slice(), vec![0, 1, 2, 0, 3, 4, 7]);
}
*/
Ok(())
}
}