Add support for removing a key. #24

src/interpolation.rs

@@ -5,7 +5,7 @@
 /// Available kind of interpolations.
 ///
 /// Feel free to visit each variant for more documentation.
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
 #[cfg_attr(feature = "serialization", derive(Deserialize, Serialize))]
 #[cfg_attr(feature = "serialization", serde(rename_all = "snake_case"))]
 pub enum Interpolation<T> {

src/key.rs

@@ -17,7 +17,7 @@ use crate::interpolation::Interpolation;
 /// key and the next one – if existing. Have a look at [`Interpolation`] for further details.
 ///
 /// [`Interpolation`]: crate::interpolation::Interpolation
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
 #[cfg_attr(feature = "serialization", derive(Deserialize, Serialize))]
 #[cfg_attr(feature = "serialization", serde(rename_all = "snake_case"))]
 pub struct Key<T, V> {

src/spline.rs

@@ -52,6 +52,18 @@ impl<T, V> Spline<T, V> {
     &self.0
   }
 
+  /// Number of keys.
+  #[inline(always)]
+  pub fn len(&self) -> usize {
+    self.0.len()
+  }
+
+  /// Check whether the spline has no key.
+  #[inline(always)]
+  pub fn is_empty(&self) -> bool {
+    self.0.is_empty()
+  }
+
   /// Sample a spline at a given time.
   ///
   /// The current implementation, based on immutability, cannot perform in constant time. This means
@@ -146,6 +158,15 @@ impl<T, V> Spline<T, V> {
       }
     })
   }
+
+  /// Remove a ke from the spline.
+  pub fn remove(&mut self, index: usize) -> Option<Key<T, V>> {
+    if index >= self.0.len() {
+      None
+    } else {
+      Some(self.0.remove(index))
+    }
+  }
 }
 
 // Normalize a time ([0;1]) given two control points.

tests/mod.rs

@@ -172,3 +172,27 @@ fn nalgebra_vector_interpolation() {
   assert_eq!(Interpolate::lerp(start, end, 1.0), end);
   assert_eq!(Interpolate::lerp(start, end, 0.5), mid);
 }
+
+#[test]
+fn remove_element_empty() {
+  let mut spline: Spline<f32, f32> = Spline::from_vec(vec![]);
+  let removed = spline.remove(0);
+
+  assert_eq!(removed, None);
+  assert!(spline.is_empty());
+}
+
+#[test]
+fn remove_element() {
+  let start = Key::new(0., 0., Interpolation::Step(0.5));
+  let k1 = Key::new(1., 5., Interpolation::Linear);
+  let k2 = Key::new(2., 0., Interpolation::Step(0.1));
+  let k3 = Key::new(3., 1., Interpolation::Linear);
+  let k4 = Key::new(10., 2., Interpolation::Linear);
+  let end = Key::new(11., 4., Interpolation::default());
+  let mut spline = Spline::from_vec(vec![start, k1, k2.clone(), k3, k4, end]);
+  let removed = spline.remove(2);
+
+  assert_eq!(removed, Some(k2));
+  assert_eq!(spline.len(), 5);
+}