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
sourceimpl<'a, T> CursorMut<'a, T>
impl<'a, T> CursorMut<'a, T>
sourcepub fn index(&self) -> Option<usize>
pub fn index(&self) -> Option<usize>
Returns the cursor position index within the LinkedList
.
This returns None
if the cursor is currently pointing to the
“ghost” non-element.
sourcepub fn move_next(&mut self)
pub fn move_next(&mut self)
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.
sourcepub fn move_prev(&mut self)
pub fn move_prev(&mut self)
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.
sourcepub fn current(&mut self) -> Option<&mut T>
pub fn current(&mut self) -> Option<&mut T>
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.
sourcepub fn peek_next(&mut self) -> Option<&mut T>
pub fn peek_next(&mut self) -> Option<&mut T>
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
.
sourcepub fn peek_prev(&mut self) -> Option<&mut T>
pub fn peek_prev(&mut self) -> Option<&mut T>
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
.
sourceimpl<'a, T> CursorMut<'a, T>
impl<'a, T> CursorMut<'a, T>
sourcepub fn insert_after(&mut self, item: T)
pub fn insert_after(&mut self, item: T)
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
.
sourcepub fn insert_before(&mut self, item: T)
pub fn insert_before(&mut self, item: T)
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
.
sourcepub fn remove_current(&mut self) -> Option<T>
pub fn remove_current(&mut self) -> Option<T>
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.
sourcepub fn remove_current_as_list(&mut self) -> Option<LinkedList<T>>
pub fn remove_current_as_list(&mut self) -> Option<LinkedList<T>>
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.
sourcepub fn splice_after(&mut self, list: LinkedList<T>)
pub fn splice_after(&mut self, list: LinkedList<T>)
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
.
sourcepub fn splice_before(&mut self, list: LinkedList<T>)
pub fn splice_before(&mut self, list: LinkedList<T>)
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
.
sourcepub fn split_after(&mut self) -> LinkedList<T>
pub fn split_after(&mut self) -> LinkedList<T>
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.
sourcepub fn split_before(&mut self) -> LinkedList<T>
pub fn split_before(&mut self) -> LinkedList<T>
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.
sourcepub fn push_front(&mut self, elt: T)
pub fn push_front(&mut self, elt: T)
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.
sourcepub fn push_back(&mut self, elt: T)
pub fn push_back(&mut self, elt: T)
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.
sourcepub fn pop_front(&mut self) -> Option<T>
pub fn pop_front(&mut self) -> Option<T>
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.
sourcepub fn pop_back(&mut self) -> Option<T>
pub fn pop_back(&mut self) -> Option<T>
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.
sourcepub fn front(&self) -> Option<&T>
pub fn front(&self) -> Option<&T>
Provides a reference to the front element of the cursor’s parent list, or None if the list is empty.
sourcepub fn front_mut(&mut self) -> Option<&mut T>
pub fn front_mut(&mut self) -> Option<&mut T>
Provides a mutable reference to the front element of the cursor’s parent list, or None if the list is empty.
sourcepub fn back(&self) -> Option<&T>
pub fn back(&self) -> Option<&T>
Provides a reference to the back element of the cursor’s parent list, or None if the list is empty.
sourcepub fn back_mut(&mut self) -> Option<&mut T>
pub fn back_mut(&mut self) -> Option<&mut T>
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);
RunTrait Implementations
impl<T: Send> Send for CursorMut<'_, T>
impl<T: Sync> Sync for CursorMut<'_, T>
Auto Trait Implementations
impl<'a, T> RefUnwindSafe for CursorMut<'a, T> where
T: RefUnwindSafe,
impl<'a, T> Unpin for CursorMut<'a, T>
impl<'a, T> !UnwindSafe for CursorMut<'a, T>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more