diff --git a/library/alloc/src/collections/btree/node.rs b/library/alloc/src/collections/btree/node.rs index c3f27c105994f..b39a1b6fd6a79 100644 --- a/library/alloc/src/collections/btree/node.rs +++ b/library/alloc/src/collections/btree/node.rs @@ -9,11 +9,8 @@ // struct Node { // keys: [K; 2 * B - 1], // vals: [V; 2 * B - 1], -// edges: if height > 0 { -// [Box>; 2 * B] -// } else { () }, -// parent: Option>>, -// parent_idx: u16, +// edges: [if height > 0 { Box> } else { () }; 2 * B], +// parent: Option<(NonNull>, u16)>, // len: u16, // } // ``` @@ -28,8 +25,8 @@ // // - 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; @@ -298,9 +295,8 @@ impl<'a, K, V> NodeRef, K, V, marker::Internal> { } impl NodeRef { - /// 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 { @@ -321,9 +317,6 @@ impl NodeRef { } /// 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. @@ -471,9 +464,6 @@ impl<'a, K, V, Type> NodeRef, K, V, Type> { } /// 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 { @@ -679,9 +669,9 @@ impl<'a, K: 'a, V: 'a> NodeRef, K, V, marker::Internal> { } impl<'a, K: 'a, V: 'a> NodeRef, 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>) { debug_assert!(self.len() > 0); @@ -705,9 +695,9 @@ impl<'a, K: 'a, V: 'a> NodeRef, K, V, marker::LeafOrInternal> { } } - /// 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>) { debug_assert!(self.len() > 0);