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use std::{
ops::{Deref, DerefMut},
time::Duration,
};
use crate::{
sounds::{
wrappers::{
AdjustableSpeed, AdjustableVolume, Controllable, Controller, FinishAfter, Pausable,
SetPaused, Stoppable,
},
MemorySound,
},
utils,
};
/// A provider of audio samples.
///
/// This is the foundational trait of this crate. A `Box<dyn Sound>` can be
/// played on a [Manager][crate::manager::Manager]. Sounds can be wrapped to
/// modify the inner sound, often by using helper functions of this trait
/// (e.g. [pausable][Sound::pausable]).
pub trait Sound: Send {
/// Returns the number of channels.
fn channel_count(&self) -> u16;
/// Returns the number of samples per second for each channel for this sound
/// (e.g. 48,000).
fn sample_rate(&self) -> u32;
/// Retrieve the next sample or notification if something has changed.
/// The first sample is for the first channel and the second is the for
/// second and so on until channel_count and then wraps back to the first
/// channel. If any NextSample variant besides `Sample` is returned then
/// the following `NextSample::Sample` is for the first channel. If a Sound
/// has returned `Paused` it is expected that the consumer will call
/// next_sample again in the future. If a Sound has returned `Finished` it
/// is not expected for the consumer to call next_sample again but if called
/// `Finished` will normally be returned again. After Finished has been
/// returned, channel_count() and sample_rate() may return different values
/// without MetadataChanged being returned.
///
/// If an error is returned it is not specified what will happen if
/// next_sample is called again. Individual implementations can specify
/// which errors are recoverable if any. Most consumers will either pass the
/// error up or log the error and stop playing the sound (e.g. `SoundMixer`
/// and `SoundList`).
fn next_sample(&mut self) -> Result<NextSample, crate::Error>;
/// Called whenever a new batch of audio samples is requested by the
/// backend.
///
/// This is a good place to put code that needs to run fairly frequently,
/// but not for every single audio sample.
fn on_start_of_batch(&mut self);
/// Returns the next sample for all channels.
///
/// It is the callers responsibility to ensure this function is only called
/// at the start of a frame (i.e. the first channel is the next to be
/// returned from next_sample).
///
/// If an Error, `Paused`, `Finished`, or `MetadataChanged` are encountered
/// while collecting samples, an Err(Ok(NextSample)) of that variant
/// will be returned and any previously collected samples are lost.
/// Err(Ok(NextSample::Sample)) will never be returned. If an error is
/// encountered Err(Err(error::Error)) is returned.
fn next_frame(&mut self) -> Result<Vec<i16>, Result<NextSample, crate::Error>> {
let mut samples = Vec::with_capacity(self.channel_count() as usize);
self.append_next_frame_to(&mut samples)?;
Ok(samples)
}
/// Same as `next_frame` but samples are appended into an existing Vec.
///
/// Any existing data is left unmodified.
fn append_next_frame_to(
&mut self,
samples: &mut Vec<i16>,
) -> Result<(), Result<NextSample, crate::Error>> {
for _ in 0..self.channel_count() {
let next = self.next_sample();
match next {
Ok(NextSample::Sample(s)) => samples.push(s),
Ok(NextSample::MetadataChanged)
| Ok(NextSample::Paused)
| Ok(NextSample::Finished)
| Err(_) => return Err(next),
}
}
Ok(())
}
/// Read the entire sound into memory. MemorySound can be cloned for
/// efficient reuse. See [MemorySound::from_sound].
fn into_memory_sound(self) -> Result<MemorySound, crate::Error>
where
Self: Sized,
{
MemorySound::from_sound(self)
}
/// Read the entire sound into memory and loop indefinitely.
///
/// If you do not want to read the entire sound into memory see
/// [SoundsFromFn][crate::sounds::SoundsFromFn] as an alternative.
fn loop_from_memory(self) -> Result<MemorySound, crate::Error>
where
Self: Sized,
{
let mut to_return = MemorySound::from_sound(self)?;
to_return.set_looping(true);
Ok(to_return)
}
/// Allow this sound to be controlled after it has started playing with a
/// [`Controller`].
///
/// What can be controlled depends on the Sound type (e.g. set_volume).
fn controllable(self) -> (Controllable<Self>, Controller<Self>)
where
Self: Sized,
{
Controllable::new(self)
}
/// Get notified via a [tokio::sync::oneshot::Receiver] when this sound
/// has Finished.
#[cfg(feature = "async")]
fn with_async_completion_notifier(
self,
) -> (
crate::sounds::wrappers::AsyncCompletionNotifier<Self>,
tokio::sync::oneshot::Receiver<()>,
)
where
Self: Sized,
{
crate::sounds::wrappers::AsyncCompletionNotifier::new(self)
}
/// Get notified via a [std::sync::mpsc::Receiver] when this sound
/// has Finished.
fn with_completion_notifier(
self,
) -> (
crate::sounds::wrappers::CompletionNotifier<Self>,
std::sync::mpsc::Receiver<()>,
)
where
Self: Sized,
{
crate::sounds::wrappers::CompletionNotifier::new(self)
}
/// Allow the volume of the sound to be adjustable with `set_volume`.
fn with_adjustable_volume(self) -> AdjustableVolume<Self>
where
Self: Sized,
{
AdjustableVolume::new(self)
}
/// Allow the volume of the sound to be adjustable with `set_volume` and set
/// the initial volume adjustment.
fn with_adjustable_volume_of(self, volume_adjustment: f32) -> AdjustableVolume<Self>
where
Self: Sized,
{
AdjustableVolume::new_with_volume(self, volume_adjustment)
}
/// Allow the speed of the sound to be adjustable with `set_speed`.
///
/// This adjusts both speed and pitch.
fn with_adjustable_speed(self) -> AdjustableSpeed<Self>
where
Self: Sized,
{
AdjustableSpeed::new(self)
}
/// Allow the speed of the sound to be adjustable with `set_speed` and set
/// the initial speed adjustment.
///
/// This adjusts both speed and pitch.
fn with_adjustable_speed_of(self, speed_adjustment: f32) -> AdjustableSpeed<Self>
where
Self: Sized,
{
AdjustableSpeed::new_with_speed(self, speed_adjustment)
}
/// Allow for the sound to be pausable with `set_paused`. Starts unpaused.
fn pausable(self) -> Pausable<Self>
where
Self: Sized,
{
Pausable::new(self)
}
/// Allow for the sound to be pausable with `set_paused`. Starts paused.
fn paused(self) -> Pausable<Self>
where
Self: Sized,
{
let mut to_return = Pausable::new(self);
to_return.set_paused(true);
to_return
}
/// Allow for the sound to be stoppable with `set_stopped`.
/// A stopped sound returns `Finished`.
fn stoppable(self) -> Stoppable<Self>
where
Self: Sized,
{
Stoppable::new(self)
}
/// Play the first `duration` of the sound, then finish even if samples
/// remain.
///
/// See [FinishAfter].
fn finish_after(self, duration: Duration) -> FinishAfter<Self>
where
Self: Sized,
{
FinishAfter::new(self, duration)
}
/// Skip the next `duration` of samples.
///
/// This is done by calling next_sample repeatedly.
///
/// Returns true if all samples were successfully skipped, false if a Paused
/// or Finished were encountered first. MetadataChanged events are handled
/// correctly but are not returned.
fn skip(&mut self, duration: Duration) -> Result<bool, crate::Error> {
let mut current_channel_count = self.channel_count();
let mut current_sample_rate = self.sample_rate();
let mut num_samples_remaining =
utils::duration_to_num_samples(duration, current_channel_count, current_sample_rate);
while num_samples_remaining > 0 {
let next = self.next_sample()?;
match next {
NextSample::Sample(_) => {
num_samples_remaining -= 1;
}
NextSample::MetadataChanged => {
let new_channel_count = self.channel_count();
let new_sample_rate = self.sample_rate();
if new_channel_count != current_channel_count
|| new_sample_rate != current_sample_rate
{
num_samples_remaining = utils::convert_num_samples(
num_samples_remaining,
current_channel_count,
current_sample_rate,
new_channel_count,
new_sample_rate,
);
current_channel_count = new_channel_count;
current_sample_rate = new_sample_rate;
}
}
NextSample::Paused => return Ok(false),
NextSample::Finished => return Ok(false),
}
}
Ok(true)
}
}
/// The result of [Sound::next_sample]
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub enum NextSample {
/// A sample for one channel. Channels are interleaved. The first sample is
/// for the first channel and so forth and repeats (e.g. L-R-L-R-L-R).
Sample(i16),
/// The number of channels or the sample rate has changed. Continue to
/// retrieve samples afterward. The next sample will always be for the
/// first track regardless of what track was next
// before this value was returned.
MetadataChanged,
/// No more samples for now. More might come later. It is expected that the
/// Sound will not be pulled again during this batch of samples.
Paused,
/// All samples have been retrieved and no more will come.
Finished,
}
impl Sound for Box<dyn Sound> {
fn on_start_of_batch(&mut self) {
self.deref_mut().on_start_of_batch()
}
fn channel_count(&self) -> u16 {
self.deref().channel_count()
}
fn sample_rate(&self) -> u32 {
self.deref().sample_rate()
}
fn next_sample(&mut self) -> Result<NextSample, crate::Error> {
self.deref_mut().next_sample()
}
}
#[cfg(test)]
#[path = "./tests/sound.rs"]
mod tests;