Struct alloc::collections::linked_list::CursorMut
source · [−]pub struct CursorMut<'a, T: 'a> { /* private fields */ }Expand description
A cursor over a LinkedList with editing operations.
A Cursor is like an iterator, except that it can freely seek back-and-forth, and can
safely mutate the list during iteration. This is because the lifetime of its yielded
references is tied to its own lifetime, instead of just the underlying list. This means
cursors cannot yield multiple elements at once.
Cursors always rest between two elements in the list, and index in a logically circular way.
To accommodate this, there is a “ghost” non-element that yields None between the head and
tail of the list.
Implementations
Returns the cursor position index within the LinkedList.
This returns None if the cursor is currently pointing to the
“ghost” non-element.
Moves the cursor to the next element of the LinkedList.
If the cursor is pointing to the “ghost” non-element then this will move it to
the first element of the LinkedList. If it is pointing to the last
element of the LinkedList then this will move it to the “ghost” non-element.
Moves the cursor to the previous element of the LinkedList.
If the cursor is pointing to the “ghost” non-element then this will move it to
the last element of the LinkedList. If it is pointing to the first
element of the LinkedList then this will move it to the “ghost” non-element.
Returns a reference to the element that the cursor is currently pointing to.
This returns None if the cursor is currently pointing to the
“ghost” non-element.
Returns a reference to the next element.
If the cursor is pointing to the “ghost” non-element then this returns
the first element of the LinkedList. If it is pointing to the last
element of the LinkedList then this returns None.
Returns a reference to the previous element.
If the cursor is pointing to the “ghost” non-element then this returns
the last element of the LinkedList. If it is pointing to the first
element of the LinkedList then this returns None.
Returns a read-only cursor pointing to the current element.
The lifetime of the returned Cursor is bound to that of the
CursorMut, which means it cannot outlive the CursorMut and that the
CursorMut is frozen for the lifetime of the Cursor.
Inserts a new element into the LinkedList after the current one.
If the cursor is pointing at the “ghost” non-element then the new element is
inserted at the front of the LinkedList.
Inserts a new element into the LinkedList before the current one.
If the cursor is pointing at the “ghost” non-element then the new element is
inserted at the end of the LinkedList.
Removes the current element from the LinkedList.
The element that was removed is returned, and the cursor is
moved to point to the next element in the LinkedList.
If the cursor is currently pointing to the “ghost” non-element then no element
is removed and None is returned.
Removes the current element from the LinkedList without deallocating the list node.
The node that was removed is returned as a new LinkedList containing only this node.
The cursor is moved to point to the next element in the current LinkedList.
If the cursor is currently pointing to the “ghost” non-element then no element
is removed and None is returned.
Inserts the elements from the given LinkedList after the current one.
If the cursor is pointing at the “ghost” non-element then the new elements are
inserted at the start of the LinkedList.
Inserts the elements from the given LinkedList before the current one.
If the cursor is pointing at the “ghost” non-element then the new elements are
inserted at the end of the LinkedList.
Splits the list into two after the current element. This will return a new list consisting of everything after the cursor, with the original list retaining everything before.
If the cursor is pointing at the “ghost” non-element then the entire contents
of the LinkedList are moved.
Splits the list into two before the current element. This will return a new list consisting of everything before the cursor, with the original list retaining everything after.
If the cursor is pointing at the “ghost” non-element then the entire contents
of the LinkedList are moved.
Appends an element to the front of the cursor’s parent list. The node that the cursor points to is unchanged, even if it is the “ghost” node.
This operation should compute in O(1) time.
Appends an element to the back of the cursor’s parent list. The node that the cursor points to is unchanged, even if it is the “ghost” node.
This operation should compute in O(1) time.
Removes the first element from the cursor’s parent list and returns it, or None if the list is empty. The element the cursor points to remains unchanged, unless it was pointing to the front element. In that case, it points to the new front element.
This operation should compute in O(1) time.
Removes the last element from the cursor’s parent list and returns it, or None if the list is empty. The element the cursor points to remains unchanged, unless it was pointing to the back element. In that case, it points to the “ghost” element.
This operation should compute in O(1) time.
Provides a reference to the front element of the cursor’s parent list, or None if the list is empty.
Provides a mutable reference to the front element of the cursor’s parent list, or None if the list is empty.
Provides a reference to the back element of the cursor’s parent list, or None if the list is empty.
Provides a mutable reference to back element of the cursor’s parent
list, or None if the list is empty.
Examples
Building and mutating a list with a cursor, then getting the back element:
#![feature(linked_list_cursors)]
use std::collections::LinkedList;
let mut dl = LinkedList::new();
dl.push_front(3);
dl.push_front(2);
dl.push_front(1);
let mut cursor = dl.cursor_front_mut();
*cursor.current().unwrap() = 99;
*cursor.back_mut().unwrap() = 0;
let mut contents = dl.into_iter();
assert_eq!(contents.next(), Some(99));
assert_eq!(contents.next(), Some(2));
assert_eq!(contents.next(), Some(0));
assert_eq!(contents.next(), None);