Struct CursorMut

pub struct CursorMut<'a, K, V, S> { /* private fields */ }

The CursorMut struct and its implementation provide the basic mutable Cursor API for Linked lists as proposed in here, with several exceptions:

• It behaves similarly to Rust’s Iterators, returning None when the end of the list is reached. A guard node is positioned between the head and tail of the linked list to facilitate this. If the cursor is over this guard node, None is returned, signaling the end or start of the list. From this position, the cursor can move in either direction as the linked list is circular, with the guard node connecting the two ends.
• The current implementation does not include an index method, as it does not track the index of its elements. It provides access to each map entry as a tuple of (&K, &mut V).

Implementations

impl<'a, K, V, S> CursorMut<'a, K, V, S>

pub fn current(&mut self) -> Option<(&K, &mut V)>

Returns an Option of the current element in the list, provided it is not the guard node, and None overwise.

pub fn peek_next(&mut self) -> Option<(&K, &mut V)>

Retrieves the next element in the list (moving towards the end).

pub fn peek_prev(&mut self) -> Option<(&K, &mut V)>

Retrieves the previous element in the list (moving towards the front).

pub fn move_next(&mut self)

Updates the pointer to the current element to the next element in the list (that is, moving towards the end).

pub fn move_prev(&mut self)

Updates the pointer to the current element to the previous element in the list (that is, moving towards the front).

pub fn insert_before(&mut self, key: K, value: V) -> Option<V>

where K: Eq + Hash, S: BuildHasher,

Inserts the provided key and value before the current element. It checks if an entry with the given key exists and, if so, replaces its value with the provided key parameter. The key is not updated; this matters for types that can be == without being identical.

If the entry doesn’t exist, it creates a new one. If a value has been updated, the function returns the old value wrapped with Some and None otherwise.

pub fn insert_after(&mut self, key: K, value: V) -> Option<V>

where K: Eq + Hash, S: BuildHasher,

Inserts the provided key and value after the current element. It checks if an entry with the given key exists and, if so, replaces its value with the provided key parameter. The key is not updated; this matters for types that can be == without being identical.

If the entry doesn’t exist, it creates a new one. If a value has been updated, the function returns the old value wrapped with Some and None otherwise.