// struct Node<K, V, height: usize> {
// keys: [K; 2 * B - 1],
// vals: [V; 2 * B - 1],
-// edges: if height > 0 {
-// [Box<Node<K, V, height - 1>>; 2 * B]
-// } else { () },
-// parent: Option<NonNull<Node<K, V, height + 1>>>,
-// parent_idx: u16,
+// edges: [if height > 0 { Box<Node<K, V, height - 1>> } else { () }; 2 * B],
+// parent: Option<(NonNull<Node<K, V, height + 1>>, u16)>,
// len: u16,
// }
// ```
//
// - Trees must have uniform depth/height. This means that every path down to a leaf from a
// given node has exactly the same length.
-// - A node of length `n` has `n` keys, `n` values, and (in an internal node) `n + 1` edges.
-// This implies that even an empty internal node has at least one edge.
+// - A node of length `n` has `n` keys, `n` values, and `n + 1` edges.
+// This implies that even an empty node has at least one edge.
use core::cmp::Ordering;
use core::marker::PhantomData;
}
impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> {
- /// Finds the length of the node. This is the number of keys or values. In an
- /// internal node, the number of edges is `len() + 1`.
- /// For any node, the number of possible edge handles is also `len() + 1`.
+ /// Finds the length of the node. This is the number of keys or values.
+ /// The number of edges is `len() + 1`.
/// Note that, despite being safe, calling this function can have the side effect
/// of invalidating mutable references that unsafe code has created.
pub fn len(&self) -> usize {
}
/// Exposes the leaf portion of any leaf or internal node.
- /// If the node is a leaf, this function simply opens up its data.
- /// If the node is an internal node, so not a leaf, it does have all the data a leaf has
- /// (header, keys and values), and this function exposes that.
///
/// Returns a raw ptr to avoid invalidating other references to this node,
/// which is possible when BorrowType is marker::ValMut.
}
/// Exposes the leaf portion of any leaf or internal node for writing.
- /// If the node is a leaf, this function simply opens up its data.
- /// If the node is an internal node, so not a leaf, it does have all the data a leaf has
- /// (header, keys and values), and this function exposes that.
///
/// We don't need to return a raw ptr because we have unique access to the entire node.
fn as_leaf_mut(&mut self) -> &'a mut LeafNode<K, V> {
}
impl<'a, K: 'a, V: 'a> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
- /// Removes a key/value pair from the end of this node and returns the pair.
- /// If this is an internal node, also removes the edge that was to the right
- /// of that pair and returns the orphaned node that this edge owned.
+ /// Removes a key/value pair from the end of the node and returns the pair.
+ /// Also removes the edge that was to the right of that pair and, if the node
+ /// is internal, returns the orphaned subtree that this edge owned.
fn pop(&mut self) -> (K, V, Option<Root<K, V>>) {
debug_assert!(self.len() > 0);
}
}
- /// Removes a key/value pair from the beginning of this node and returns the pair.
- /// If this is an internal node, also removes the edge that was to the left
- /// of that pair and returns the orphaned node that this edge owned.
+ /// Removes a key/value pair from the beginning of the node and returns the pair.
+ /// Also removes the edge that was to the left of that pair and, if the node is
+ /// internal, returns the orphaned subtree that this edge owned.
fn pop_front(&mut self) -> (K, V, Option<Root<K, V>>) {
debug_assert!(self.len() > 0);