mirror

this closes #152

README.md

@@ -706,6 +706,7 @@ math
 - `mod([float])` `rem([float])`
 - `clip([float, float])` e.g. `clip()` takes 1 input and clips to [-1...1], `clip(-5, 5)` clips to [-5...5]
 - `wrap(float, [float])` wrap between 2 numbers (or between 0 and x if only one number is given)
+- `mirror(float, float)` mirror (wave fold) between two values
 - `log([float])`
 - `bitand([float])`
 - `bitor([float])`

src/functions.rs

@@ -862,6 +862,20 @@ pub fn str_to_net(op: &str) -> Net32 {
                 return Net32::wrap(Box::new(map(move |i: &Frame<f32, U1>| i[0] - x * (i[0] / x).floor())));
             }
         }
+        // thanks to csound's mirror opcode
+        "mirror" => {
+            if let Some(p) = p.get(0..2) {
+                let (p0, p1) = (min(p[0], p[1]), max(p[0], p[1]));
+                return Net32::wrap(Box::new(map(move |i: &Frame<f32, U1>| {
+                    let mut n = i[0];
+                    n = if n.is_normal() { n } else { 0. };
+                    while n > p1 || n < p0 {
+                        n = if n > p1 { p1+p1-n } else { p0+p0-n };
+                    }
+                    n
+                })));
+            }
+        }
         _ => {}
     }
     Net32::wrap(Box::new(dc(0.)))