Add array.rs

src/array.rs

@@ -0,0 +1,98 @@
+use std::ops::{Index, IndexMut};
+
+/// A two dimensional statically size array.
+pub struct Array2D<T> {
+    width: usize,
+    height: usize,
+    values: Vec<T>
+}
+
+impl<T: Default + Copy> Array2D<T> {
+    pub fn new(width: usize, height: usize) -> Self {
+        Self {
+            width,
+            height,
+            values: vec![T::default(); width * height]
+        }
+    }
+
+    pub fn width(&self) -> usize {
+        self.width
+    }
+
+    pub fn height(&self) -> usize {
+        self.height
+    }
+
+    /// Calculates the physical index of the given position.
+    ///
+    /// # Panics
+    /// Panics if the position is out of bounds.
+    fn index_of(&self, pos: (usize, usize)) -> usize {
+        assert!(pos.0 < self.width);
+        assert!(pos.1 < self.height);
+        pos.0 + pos.1 * self.width
+    }
+}
+
+impl<T: Default + Copy> Index<(usize, usize)> for Array2D<T> {
+    type Output = T;
+
+    fn index(&self, pos: (usize, usize)) -> &Self::Output {
+        unsafe { self.values.get_unchecked(self.index_of(pos)) }
+    }
+}
+
+impl<T: Default + Copy> IndexMut<(usize, usize)> for Array2D<T> {
+    fn index_mut(&mut self, pos: (usize, usize)) -> &mut Self::Output {
+        let i = self.index_of(pos);
+
+        unsafe { self.values.get_unchecked_mut(i) }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::array::Array2D;
+
+    #[test]
+    fn width() {
+        let array = Array2D::<()>::new(10, 4);
+
+        assert_eq!(10, array.width());
+    }
+
+    #[test]
+    fn height() {
+        let array = Array2D::<()>::new(2, 5);
+
+        assert_eq!(5, array.height());
+    }
+
+    #[test]
+    fn index() {
+        let mut array = Array2D::new(4, 4);
+
+        array[(1, 2)] = 3;
+        array[(3, 3)] = 7;
+
+        assert_eq!(3, array[(1, 2)]);
+        assert_eq!(7, array[(3, 3)]);
+    }
+
+    #[test]
+    #[should_panic]
+    fn index_oob_width() {
+        let array = Array2D::<()>::new(5, 10);
+
+        array[(8, 2)];
+    }
+
+    #[test]
+    #[should_panic]
+    fn index_oob_height() {
+        let array = Array2D::<()>::new(10, 5);
+
+        array[(3, 7)];
+    }
+}

src/main.rs

@@ -6,6 +6,7 @@ mod color;
 mod char;
 mod fill;
 mod vec;
+mod array;
 
 #[derive(Parser)]
 #[clap(author = "Rico Riedel", version = "0.1.0", about = "Wipe your terminal with a random animation.")]