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use std::time::Duration;
use Sample;
use Source;
pub fn delay<I>(input: I, duration: Duration) -> Delay<I>
where
I: Source,
I::Item: Sample,
{
let duration_ns = duration.as_secs() * 1000000000 + duration.subsec_nanos() as u64;
let samples = duration_ns * input.sample_rate() as u64 * input.channels() as u64 / 1000000000;
Delay {
input: input,
remaining_samples: samples as usize,
requested_duration: duration,
}
}
#[derive(Clone, Debug)]
pub struct Delay<I> {
input: I,
remaining_samples: usize,
requested_duration: Duration,
}
impl<I> Delay<I>
where
I: Source,
I::Item: Sample,
{
#[inline]
pub fn inner(&self) -> &I {
&self.input
}
#[inline]
pub fn inner_mut(&mut self) -> &mut I {
&mut self.input
}
#[inline]
pub fn into_inner(self) -> I {
self.input
}
}
impl<I> Iterator for Delay<I>
where
I: Source,
I::Item: Sample,
{
type Item = <I as Iterator>::Item;
#[inline]
fn next(&mut self) -> Option<<I as Iterator>::Item> {
if self.remaining_samples >= 1 {
self.remaining_samples -= 1;
Some(Sample::zero_value())
} else {
self.input.next()
}
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
let (min, max) = self.input.size_hint();
(
min + self.remaining_samples,
max.map(|v| v + self.remaining_samples),
)
}
}
impl<I> Source for Delay<I>
where
I: Iterator + Source,
I::Item: Sample,
{
#[inline]
fn current_frame_len(&self) -> Option<usize> {
self.input
.current_frame_len()
.map(|val| val + self.remaining_samples)
}
#[inline]
fn channels(&self) -> u16 {
self.input.channels()
}
#[inline]
fn sample_rate(&self) -> u32 {
self.input.sample_rate()
}
#[inline]
fn total_duration(&self) -> Option<Duration> {
self.input
.total_duration()
.map(|val| val + self.requested_duration)
}
}