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use std::time::Duration;
use Sample;
use Source;
pub fn take_duration<I>(input: I, duration: Duration) -> TakeDuration<I>
where I: Source,
I::Item: Sample
{
TakeDuration {
input: input,
remaining_duration: duration,
requested_duration: duration,
}
}
#[derive(Clone, Debug)]
pub struct TakeDuration<I>
where I: Source,
I::Item: Sample
{
input: I,
remaining_duration: Duration,
requested_duration: Duration,
}
impl<I> TakeDuration<I>
where I: Source,
I::Item: Sample
{
#[inline]
fn get_duration_per_sample(&self) -> Duration {
let ns = 1000000000 / (self.input.sample_rate() as u64 * self.channels() as u64);
Duration::new(0, ns as u32)
}
}
impl<I> Iterator for TakeDuration<I>
where I: Source,
I::Item: Sample
{
type Item = <I as Iterator>::Item;
fn next(&mut self) -> Option<<I as Iterator>::Item> {
let duration_per_sample = self.get_duration_per_sample();
if self.remaining_duration <= duration_per_sample {
None
} else {
if let Some(sample) = self.input.next() {
self.remaining_duration = self.remaining_duration - duration_per_sample;
Some(sample)
} else {
None
}
}
}
}
impl<I> Source for TakeDuration<I>
where I: Iterator + Source,
I::Item: Sample
{
#[inline]
fn current_frame_len(&self) -> Option<usize> {
let remaining_nanosecs = self.remaining_duration.as_secs() * 1000000000 +
self.remaining_duration.subsec_nanos() as u64;
let remaining_samples = remaining_nanosecs * self.input.sample_rate() as u64 *
self.channels() as u64 / 1000000000;
if let Some(value) = self.input.current_frame_len() {
if (value as u64) < remaining_samples {
Some(value)
} else {
Some(remaining_samples as usize)
}
} else {
Some(remaining_samples as usize)
}
}
#[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> {
if let Some(duration) = self.input.total_duration() {
if duration < self.requested_duration {
Some(duration)
} else {
Some(self.requested_duration)
}
} else {
None
}
}
}