Initial commit

src/identifier.rs

@@ -0,0 +1,35 @@
+#![allow(clippy::module_name_repetitions)]
+
+pub type TreeIdentifier<'a> = &'a [usize];
+pub type TreeIdentifierVec = Vec<usize>;
+
+pub fn get_without_leaf(identifier: &[usize]) -> (&[usize], Option<&usize>) {
+    let length = identifier.len();
+    let length_without_leaf = length.saturating_sub(1);
+
+    let head = &identifier[0..length_without_leaf];
+    let tail = identifier.get(length_without_leaf);
+
+    (head, tail)
+}
+
+#[test]
+fn get_without_leaf_empty() {
+    let (head, tail) = get_without_leaf(&[]);
+    assert_eq!(head.len(), 0);
+    assert_eq!(tail, None);
+}
+
+#[test]
+fn get_without_leaf_single() {
+    let (head, tail) = get_without_leaf(&[2]);
+    assert_eq!(head.len(), 0);
+    assert_eq!(tail, Some(&2));
+}
+
+#[test]
+fn get_without_leaf_multiple() {
+    let (head, tail) = get_without_leaf(&[2, 4, 6]);
+    assert_eq!(head, [2, 4]);
+    assert_eq!(tail, Some(&6));
+}