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use std::time::Duration;
use Sample;
use Source;
#[derive(Clone, Debug)]
pub struct ChannelVolume<I>
where
I: Source,
I::Item: Sample,
{
input: I,
channel_volumes: Vec<f32>,
current_channel: usize,
current_sample: Option<I::Item>,
}
impl<I> ChannelVolume<I>
where
I: Source,
I::Item: Sample,
{
pub fn new(mut input: I, channel_volumes: Vec<f32>) -> ChannelVolume<I>
where
I: Source,
I::Item: Sample,
{
let mut sample = None;
for _ in 0 .. input.channels() {
if let Some(s) = input.next() {
sample = Some(sample
.get_or_insert_with(|| I::Item::zero_value())
.saturating_add(s));
}
}
ChannelVolume {
input,
channel_volumes,
current_channel: 0,
current_sample: sample,
}
}
pub fn set_volume(&mut self, channel: usize, volume: f32) {
self.channel_volumes[channel] = volume;
}
#[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 ChannelVolume<I>
where
I: Source,
I::Item: Sample,
{
type Item = I::Item;
#[inline]
fn next(&mut self) -> Option<I::Item> {
let ret = self.current_sample
.map(|sample| sample.amplify(self.channel_volumes[self.current_channel]));
self.current_channel += 1;
if self.current_channel >= self.channel_volumes.len() {
self.current_channel = 0;
self.current_sample = None;
for _ in 0 .. self.input.channels() {
if let Some(s) = self.input.next() {
self.current_sample = Some(self.current_sample
.get_or_insert_with(|| I::Item::zero_value())
.saturating_add(s));
}
}
}
return ret;
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.input.size_hint()
}
}
impl<I> ExactSizeIterator for ChannelVolume<I>
where
I: Source + ExactSizeIterator,
I::Item: Sample,
{
}
impl<I> Source for ChannelVolume<I>
where
I: Source,
I::Item: Sample,
{
#[inline]
fn current_frame_len(&self) -> Option<usize> {
self.input.current_frame_len()
}
#[inline]
fn channels(&self) -> u16 {
self.channel_volumes.len() as u16
}
#[inline]
fn sample_rate(&self) -> u32 {
self.input.sample_rate()
}
#[inline]
fn total_duration(&self) -> Option<Duration> {
self.input.total_duration()
}
}