Struct Cursor

pub struct Cursor<K: Key> { /* private fields */ }

Cursor points to a key value pair in the tree. Not like Iterator, it can move to next or prev.

Implementations

impl<'k, K: Key + 'k> Cursor<K>

pub fn key(&self) -> &K

Get the key of the cursor.

pub fn first<'b, S: NodeStore<K = K>>( tree: &'b BPlusTree<S>, ) -> Option<(Self, &'b S::V)>

where 'k: 'b,

Create a Cursor pointing to the first key-value pair in the tree.

pub fn last<'b, S: NodeStore<K = K>>( tree: &'b BPlusTree<S>, ) -> Option<(Self, &'b S::V)>

where 'k: 'b,

Create a Cursor pointing to the last key-value pair in the tree. If the key for self is deleted, then this returns the cursor for the key value pair just larger than the deleted key.

pub fn prev<'a, 'b, S: NodeStore<K = K>>( &'a self, tree: &'b BPlusTree<S>, ) -> Option<Self>

Get the Cursor points to the prev key-value pair. If the key for self is deleted, then this returns the cursor for the key value pair just under the deleted key.

pub fn prev_with_value<'a, 'b, S: NodeStore<K = K>>( &'a self, tree: &'b BPlusTree<S>, ) -> Option<(Self, &'b S::V)>

where 'k: 'b,

Get the Cursor points to the prev key-value pair, also with a reference to the value. This is faster than first prev, then value.

pub fn next<'a, 'b, S: NodeStore<K = K>>( &'a self, tree: &'b BPlusTree<S>, ) -> Option<Self>

Get the Cursor points to the next key-value pair. If the key for self is deleted, then this returns the cursor for the key value pair just larger than the deleted key.

pub fn next_with_value<'a, 'b, S: NodeStore<K = K>>( &'a self, tree: &'b BPlusTree<S>, ) -> Option<(Self, &'b S::V)>

where 'k: 'b,

Get the Cursor points to the next key-value pair, also with a reference to the value.

pub fn exists<'a, 'b, S: NodeStore<K = K>>( &'a self, tree: &'b BPlusTree<S>, ) -> bool

whether current cursor is still valid

pub fn value<'a, 'b, S: NodeStore<K = K>>( &'a self, tree: &'b BPlusTree<S>, ) -> Option<&'b S::V>

where 'k: 'b,

get the value attached to cursor, if the underlying key is deleted, this returns None

Trait Implementations

impl<K: Clone + Key> Clone for Cursor<K>

fn clone(&self) -> Cursor<K>

Returns a duplicate of the value.

const fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<K: Debug + Key> Debug for Cursor<K>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<K: Copy + Key> Copy for Cursor<K>