feat: "Ramp" sound source for testing and debugging

src/sources/mod.rs

@@ -1,7 +1,9 @@
 //! Useful implementations of `rodio::Source`
 
-mod noise;
 mod constant;
+mod noise;
+mod ramp;
 
-pub use self::noise::Noise;
 pub use self::constant::Constant;
+pub use self::noise::Noise;
+pub use self::ramp::Ramp;

src/sources/ramp.rs

@@ -0,0 +1,49 @@
+use rodio::Source;
+use std::time::Duration;
+
+/// Constant source
+pub struct Ramp {
+    sample_rate: u32,
+    value: f32,
+}
+
+impl Ramp {
+    pub fn new(sample_rate: u32) -> Self {
+        Ramp {
+            sample_rate,
+            value: 0.0,
+        }
+    }
+}
+
+impl Iterator for Ramp {
+    type Item = f32;
+
+    fn next(&mut self) -> Option<f32> {
+        let x = self.value;
+        self.value += 1.0 / self.sample_rate as f32;
+        Some(x)
+    }
+}
+
+impl Source for Ramp {
+    #[inline(always)]
+    fn current_frame_len(&self) -> Option<usize> {
+        None
+    }
+
+    #[inline(always)]
+    fn channels(&self) -> u16 {
+        1
+    }
+
+    #[inline(always)]
+    fn sample_rate(&self) -> u32 {
+        self.sample_rate
+    }
+
+    #[inline(always)]
+    fn total_duration(&self) -> Option<Duration> {
+        None
+    }
+}