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use crate::AudioStreamParams;
/// An object to read audio samples from.
pub trait AudioPipe {
/// The audio stream parameters of the audio pipe.
fn stream_params(&self) -> &'_ AudioStreamParams;
/// Reads samples from the pipe.
///
/// When using in a MIDI synthesizer, the amount of samples determines the
/// time of the current active MIDI events. For example if we send a note
/// on event and read 44100 samples (with a 44.1kHz sample rate), then the
/// note will be audible for 1 second. If after reading those samples we
/// send a note off event for the same key, then on the next read the key
/// will be released. If we don't, then the note will keep playing.
fn read_samples(&mut self, to: &mut [f32]) {
assert!(to
.len()
.is_multiple_of(self.stream_params().channels.count() as usize));
self.read_samples_unchecked(to);
}
/// Reads samples from the pipe without checking the channel count of the output.
fn read_samples_unchecked(&mut self, to: &mut [f32]);
}
pub struct FunctionAudioPipe<F: 'static + FnMut(&mut [f32]) + Send> {
func: F,
stream_params: AudioStreamParams,
}
impl<F: 'static + FnMut(&mut [f32]) + Send> AudioPipe for FunctionAudioPipe<F> {
fn stream_params(&self) -> &'_ AudioStreamParams {
&self.stream_params
}
fn read_samples_unchecked(&mut self, to: &mut [f32]) {
(self.func)(to);
}
}
impl<F: 'static + FnMut(&mut [f32]) + Send> FunctionAudioPipe<F> {
pub fn new(stream_params: AudioStreamParams, func: F) -> Self {
FunctionAudioPipe {
func,
stream_params,
}
}
}