1 files changed, 72 insertions, 0 deletions
diff --git a/CLI/rust/src/game_of_life/simulation/plane.rs b/CLI/rust/src/game_of_life/simulation/plane.rs
new file mode 100644
index 0000000..10acd43
--- /dev/null
+++ b/CLI/rust/src/game_of_life/simulation/plane.rs
@@ -0,0 +1,72 @@
+use std::ops::{Index, IndexMut};
+use super::circular_index;
+
+/// Game of Life universe building blocks (a plane is a circular Vec)
+///
+/// This is used internally in the implementation of the Universe to allow
+/// more readable and safer traversing of the universe blocks
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) struct Plane(pub Vec<bool>);
+
+impl Index<isize> for Plane {
+    type Output = bool;
+    fn index(&self, idx: isize) -> &bool {
+        let len = self.0.len() as isize;
+        &self.0[circular_index(idx, len)]
+    }
+}
+
+impl IndexMut<isize> for Plane {
+    fn index_mut(&mut self, idx: isize) -> &mut Self::Output {
+        let len = self.0.len() as isize;
+        &mut self.0[circular_index(idx, len)]
+    }
+}
+
+#[cfg(test)]
+mod plane {
+    use super::*;
+
+    mod index {
+        use super::*;
+
+        #[test]
+        fn get_element() {
+            let p = Plane(vec![false, false, true, false, false]);
+            assert_eq!(p[0], false);
+            assert_eq!(p[1], false);
+            assert_eq!(p[3], false);
+            assert_eq!(p[4], false);
+
+            assert_eq!(p[-3], true);
+            assert_eq!(p[2], true);
+            assert_eq!(p[7], true);
+        }
+    }
+
+    #[cfg(test)]
+    mod index_mut {
+        use super::*;
+
+        #[test]
+        fn set_negative_index_element() {
+            let mut p = Plane(vec![false, false, false, false, false]);
+            p[-3] = true;
+            assert_eq!(p, Plane(vec![false, false, true, false, false]));
+        }
+
+        #[test]
+        fn set_element() {
+            let mut p = Plane(vec![false, false, false, false, false]);
+            p[2] = true;
+            assert_eq!(p, Plane(vec![false, false, true, false, false]));
+        }
+
+        #[test]
+        fn set_out_of_bound_element() {
+            let mut p = Plane(vec![false, false, false, false, false]);
+            p[7] = true;
+            assert_eq!(p, Plane(vec![false, false, true, false, false]));
+        }
+    }
+}