Adds benchmarks for effects and type conversions

Benchmarks use the music.wav file, we use *divan* as benchmark harnass.
The time needed to load the wav file is excluded from the benchmark
by preparing the data into a special test Source. That source also
enables converting between formats.

In the future *divan* will add support for structured (json) output.
Then we could integrate with the bencher service to generate benchmark
reports for all PR's and keep a timeseries of performance.

Cargo.toml

@@ -47,6 +47,16 @@ quickcheck = "0.9.2"
 rstest = "0.18.2"
 rstest_reuse = "0.6.0"
 approx = "0.5.1"
+dasp_sample = "0.11.0"
+divan = "0.1.14"
+
+[[bench]]
+name = "effects"
+harness = false
+
+[[bench]]
+name = "conversions"
+harness = false
 
 [[example]]
 name = "music_m4a"

benches/conversions.rs

@@ -0,0 +1,21 @@
+use cpal::FromSample;
+use divan::Bencher;
+use rodio::Source;
+
+mod shared;
+use shared::TestSource;
+
+fn main() {
+    divan::main();
+}
+
+#[divan::bench(types = [i16, u16, f32])]
+fn from_i16_to<T: rodio::Sample + FromSample<i16>>(bencher: Bencher) {
+    bencher
+        .with_inputs(|| TestSource::music_wav())
+        .bench_values(|source| {
+            source
+                .convert_samples::<T>()
+                .for_each(divan::black_box_drop)
+        })
+}

benches/effects.rs

@@ -0,0 +1,48 @@
+use std::time::Duration;
+
+use divan::Bencher;
+use rodio::Source;
+
+mod shared;
+use shared::TestSource;
+
+fn main() {
+    divan::main();
+}
+
+#[divan::bench]
+fn reverb(bencher: Bencher) {
+    bencher
+        .with_inputs(|| TestSource::music_wav())
+        .bench_values(|source| {
+            source
+                .buffered()
+                .reverb(Duration::from_secs_f32(0.05), 0.3)
+                .for_each(divan::black_box_drop)
+        })
+}
+
+#[divan::bench]
+fn high_pass(bencher: Bencher) {
+    bencher
+        .with_inputs(|| TestSource::music_wav().to_f32s())
+        .bench_values(|source| source.high_pass(200).for_each(divan::black_box_drop))
+}
+
+#[divan::bench]
+fn fade_out(bencher: Bencher) {
+    bencher
+        .with_inputs(|| TestSource::music_wav())
+        .bench_values(|source| {
+            source
+                .fade_out(Duration::from_secs(5))
+                .for_each(divan::black_box_drop)
+        })
+}
+
+#[divan::bench]
+fn amplify(bencher: Bencher) {
+    bencher
+        .with_inputs(|| TestSource::music_wav().to_f32s())
+        .bench_values(|source| source.amplify(0.8).for_each(divan::black_box_drop))
+}

benches/shared.rs

@@ -0,0 +1,83 @@
+use std::io::Cursor;
+use std::time::Duration;
+use std::vec;
+
+use rodio::Source;
+
+pub struct TestSource<T> {
+    samples: vec::IntoIter<T>,
+    channels: u16,
+    sample_rate: u32,
+    total_duration: Duration,
+}
+
+impl<T> Iterator for TestSource<T> {
+    type Item = T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.samples.next()
+    }
+}
+
+impl<T> ExactSizeIterator for TestSource<T> {
+    fn len(&self) -> usize {
+        self.samples.len()
+    }
+}
+
+impl<T: rodio::Sample> Source for TestSource<T> {
+    fn current_frame_len(&self) -> Option<usize> {
+        None // forever
+    }
+
+    fn channels(&self) -> u16 {
+        self.channels
+    }
+
+    fn sample_rate(&self) -> u32 {
+        self.sample_rate
+    }
+
+    fn total_duration(&self) -> Option<Duration> {
+        Some(self.total_duration)
+    }
+}
+
+impl TestSource<i16> {
+    pub fn music_wav() -> Self {
+        let data = include_bytes!("../assets/music.wav");
+        let cursor = Cursor::new(data);
+
+        let duration = Duration::from_secs(10);
+        let sound = rodio::Decoder::new(cursor)
+            .expect("music.wav is correctly encoded & wav is supported")
+            .take_duration(duration);
+
+        TestSource {
+            channels: sound.channels(),
+            sample_rate: sound.sample_rate(),
+            total_duration: duration,
+            samples: sound.into_iter().collect::<Vec<_>>().into_iter(),
+        }
+    }
+
+    #[allow(unused, reason = "not everything from shared is used in all libs")]
+    pub fn to_f32s(self) -> TestSource<f32> {
+        let TestSource {
+            samples,
+            channels,
+            sample_rate,
+            total_duration,
+        } = self;
+        let samples = samples
+            .map(|s| cpal::Sample::from_sample(s))
+            .collect::<Vec<_>>()
+            .into_iter();
+        TestSource {
+            samples,
+            channels,
+            sample_rate,
+            total_duration,
+        }
+    }
+}