pub struct CursorMut<'a, K, V, A = Global>
where K: 'a, V: 'a,
{ /* private fields */ }
🔬This is a nightly-only experimental API. (btree_cursors)
Expand description

A cursor over a BTreeMap with editing operations.

A Cursor is like an iterator, except that it can freely seek back-and-forth, and can safely mutate the tree during iteration. This is because the lifetime of its yielded references is tied to its own lifetime, instead of just the underlying tree. This means cursors cannot yield multiple elements at once.

Cursors always point to an element in the tree, and index in a logically circular way. To accommodate this, there is a “ghost” non-element that yields None between the last and first elements of the tree.

A Cursor is created with the BTreeMap::lower_bound_mut and BTreeMap::upper_bound_mut methods.

Implementations§

source§

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

source

pub fn move_next(&mut self)

🔬This is a nightly-only experimental API. (btree_cursors)

Moves the cursor to the next element of the BTreeMap.

If the cursor is pointing to the “ghost” non-element then this will move it to the first element of the BTreeMap. If it is pointing to the last element of the BTreeMap then this will move it to the “ghost” non-element.

source

pub fn move_prev(&mut self)

🔬This is a nightly-only experimental API. (btree_cursors)

Moves the cursor to the previous element of the BTreeMap.

If the cursor is pointing to the “ghost” non-element then this will move it to the last element of the BTreeMap. If it is pointing to the first element of the BTreeMap then this will move it to the “ghost” non-element.

source

pub fn key(&self) -> Option<&K>

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a reference to the key of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

source

pub fn value(&self) -> Option<&V>

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a reference to the value of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

source

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

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a reference to the key and value of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

source

pub fn value_mut(&mut self) -> Option<&mut V>

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a mutable reference to the value of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

source

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

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a reference to the key and mutable reference to the value of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

source

pub unsafe fn key_mut_unchecked(&mut self) -> Option<&mut K>

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a mutable reference to the key of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

Safety

This can be used to modify the key, but you must ensure that the BTreeMap invariants are maintained. Specifically:

  • The key must remain unique within the tree.
  • The key must remain in sorted order with regards to other elements in the tree.
source

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

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a reference to the key and value of the next element.

If the cursor is pointing to the “ghost” non-element then this returns the first element of the BTreeMap. If it is pointing to the last element of the BTreeMap then this returns None.

source

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

🔬This is a nightly-only experimental API. (btree_cursors)

Returns a reference to the key and value of the previous element.

If the cursor is pointing to the “ghost” non-element then this returns the last element of the BTreeMap. If it is pointing to the first element of the BTreeMap then this returns None.

source

pub fn as_cursor(&self) -> Cursor<'_, K, V>

🔬This is a nightly-only experimental API. (btree_cursors)

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.

source§

impl<'a, K, V, A> CursorMut<'a, K, V, A>
where K: Ord, A: Allocator + Clone,

source

pub unsafe fn insert_after_unchecked(&mut self, key: K, value: V)

🔬This is a nightly-only experimental API. (btree_cursors)

Inserts a new element into the BTreeMap 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 BTreeMap.

Safety

You must ensure that the BTreeMap invariants are maintained. Specifically:

  • The key of the newly inserted element must be unique in the tree.
  • All keys in the tree must remain in sorted order.
source

pub unsafe fn insert_before_unchecked(&mut self, key: K, value: V)

🔬This is a nightly-only experimental API. (btree_cursors)

Inserts a new element into the BTreeMap 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 BTreeMap.

Safety

You must ensure that the BTreeMap invariants are maintained. Specifically:

  • The key of the newly inserted element must be unique in the tree.
  • All keys in the tree must remain in sorted order.
source

pub fn insert_after(&mut self, key: K, value: V)

🔬This is a nightly-only experimental API. (btree_cursors)

Inserts a new element into the BTreeMap 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 BTreeMap.

Panics

This function panics if:

  • the given key compares less than or equal to the current element (if any).
  • the given key compares greater than or equal to the next element (if any).
source

pub fn insert_before(&mut self, key: K, value: V)

🔬This is a nightly-only experimental API. (btree_cursors)

Inserts a new element into the BTreeMap 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 BTreeMap.

Panics

This function panics if:

  • the given key compares greater than or equal to the current element (if any).
  • the given key compares less than or equal to the previous element (if any).
source

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

🔬This is a nightly-only experimental API. (btree_cursors)

Removes the current element from the BTreeMap.

The element that was removed is returned, and the cursor is moved to point to the next element in the BTreeMap.

If the cursor is currently pointing to the “ghost” non-element then no element is removed and None is returned. The cursor is not moved in this case.

source

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

🔬This is a nightly-only experimental API. (btree_cursors)

Removes the current element from the BTreeMap.

The element that was removed is returned, and the cursor is moved to point to the previous element in the BTreeMap.

If the cursor is currently pointing to the “ghost” non-element then no element is removed and None is returned. The cursor is not moved in this case.

Trait Implementations§

source§

impl<K, V, A> Debug for CursorMut<'_, K, V, A>
where K: Debug, V: Debug,

source§

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

§

impl<'a, K, V, A> RefUnwindSafe for CursorMut<'a, K, V, A>

§

impl<'a, K, V, A> Send for CursorMut<'a, K, V, A>
where A: Send, K: Send, V: Send,

§

impl<'a, K, V, A> Sync for CursorMut<'a, K, V, A>
where A: Sync, K: Sync, V: Sync,

§

impl<'a, K, V, A> Unpin for CursorMut<'a, K, V, A>

§

impl<'a, K, V, A = Global> !UnwindSafe for CursorMut<'a, K, V, A>

Blanket Implementations§

source§

impl<T> Any for T
where T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T, U> AsBindGroupShaderType<U> for T
where U: ShaderType, &'a T: for<'a> Into<U>,

source§

fn as_bind_group_shader_type(&self, _images: &RenderAssets<Image>) -> U

Return the T ShaderType for self. When used in AsBindGroup derives, it is safe to assume that all images in self exist.
source§

impl<T> Borrow<T> for T
where T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> Downcast<T> for T

source§

fn downcast(&self) -> &T

source§

impl<T> Downcast for T
where T: Any,

source§

fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
source§

fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
source§

fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
source§

fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
source§

impl<T> DowncastSync for T
where T: Any + Send + Sync,

source§

fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Send + Sync>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<S> FromSample<S> for S

source§

fn from_sample_(s: S) -> S

source§

impl<T> Instrument for T

source§

fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
source§

fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
source§

impl<T, U> Into<U> for T
where U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<T, U> ToSample<U> for T
where U: FromSample<T>,

source§

fn to_sample_(self) -> U

source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
source§

impl<T> Upcast<T> for T

source§

fn upcast(&self) -> Option<&T>

source§

impl<T> WithSubscriber for T

source§

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
source§

fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
source§

impl<S, T> Duplex<S> for T
where T: FromSample<S> + ToSample<S>,

source§

impl<T> Settings for T
where T: 'static + Send + Sync,

source§

impl<T> WasmNotSend for T
where T: Send,

source§

impl<T> WasmNotSendSync for T

source§

impl<T> WasmNotSync for T
where T: Sync,