Method prev_leaf

cranelift/bforest/src/path.rs:195–202

Move the path to the last entry of the previous leaf node, if one exists. Returns the new leaf node if it exists. Leave the path unchanged and returns `None` if we are already at the first leaf node.

(&mut self, pool: &NodePool<F>)

    ///
    /// Leave the path unchanged and returns `None` if we are already at the first leaf node.
    fn prev_leaf(&mut self, pool: &NodePool<F>) -> Option<Node> {
        self.left_sibling_branch_level(self.size - 1).map(|bl| {
            let entry = self.entry[bl] - 1;
            self.entry[bl] = entry;
            let (_, bnodes) = pool[self.node[bl]].unwrap_inner();
            self.goto_subtree_last(bl + 1, bnodes[usize::from(entry)], pool)
        })
    }

    /// Move this path to the last position for the sub-tree at `level, root`.
    fn goto_subtree_last(&mut self, level: usize, root: Node, pool: &NodePool<F>) -> Node {