samp_delay()

README.md

@@ -771,6 +771,7 @@ other
 - `reverb_stereo(float, [float], [float])` (room size, reverberation time, damping) when damping isn't provided it defaults to 1, time defaults to 5
 - `tap(float, float)` (min delay time, max delay time)
 - `tap_linear(float, float)` (same)
+- `samp_delay(float)` argument is max delay time (in samples), node takes 2 inputs (signal, delay time in samples)
 
 math
 - `add(float, [float], [float], ...)` (up to 8 params)

src/functions.rs

@@ -641,6 +641,11 @@ pub fn str_to_net(op: &str) -> Net {
                 return Net::wrap(Box::new(tap_linear(min(p0, p1), max(p0, p1))));
             }
         }
+        "samp_delay" => {
+            if let Some(p) = p.first() {
+                return Net::wrap(Box::new(An(SampDelay::new(*p as usize))));
+            }
+        }
         // thanks to the pdhalf csound opcode
         // https://github.com/csound/csound/blob/master/Opcodes/shape.c#L299
         "pdhalf_bi" => {

src/nodes.rs

@@ -1,6 +1,7 @@
 use crossbeam_channel::Receiver;
 use fundsp::fft::*;
 use fundsp::hacker32::*;
+use std::collections::VecDeque;
 
 /// switch between nets based on index
 /// - input 0: index
@@ -637,3 +638,41 @@ impl AudioNode for Ifft {
         self.output.fill(Complex32::ZERO);
     }
 }
+
+/// variable delay with input time in samples
+/// - input 0: signal
+/// - input 1: delay time in samples
+/// - output 0: delayed signal
+#[derive(Clone)]
+pub struct SampDelay {
+    buffer: VecDeque<f32>,
+    max: usize,
+}
+
+impl SampDelay {
+    pub fn new(max: usize) -> Self {
+        let mut buffer = VecDeque::new();
+        buffer.resize(max, 0.);
+        SampDelay { buffer, max }
+    }
+}
+
+impl AudioNode for SampDelay {
+    const ID: u64 = 1122;
+    type Inputs = U2;
+    type Outputs = U1;
+
+    #[inline]
+    fn tick(&mut self, input: &Frame<f32, Self::Inputs>) -> Frame<f32, Self::Outputs> {
+        self.buffer.push_front(input[0]);
+        let _ = self.buffer.pop_back();
+        let out = self.buffer.get(input[1] as usize).unwrap_or(&0.);
+        [*out].into()
+    }
+
+    fn reset(&mut self) {
+        let mut new = VecDeque::new();
+        new.resize(self.max, 0.);
+        self.buffer = new;
+    }
+}