Struct sanakirja_core::btree::Cursor

pub struct Cursor<K: ?Sized, V: ?Sized, P: BTreePage<K, V>> { /* private fields */ }

A position in a B tree.

Implementations

impl<K: ?Sized + Storable, V: ?Sized + Storable, P: BTreePage<K, V>> Cursor<K, V, P>

pub fn new<T: LoadPage>(txn: &T, db: &Db_<K, V, P>) -> Result<Self, T::Error>

Create a new cursor, initialised to the first entry of the B tree.

pub fn reset<'a, T: LoadPage>(&mut self)

Reset the cursor to the first element of the database.

pub fn set<'a, T: LoadPage>( &mut self, txn: &'a T, k: &K, v: Option<&V> ) -> Result<Option<(&'a K, &'a V)>, T::Error>

Set the cursor to the first position larger than or equal to the specified key and value.

pub fn set_last<'a, T: LoadPage>(&mut self, txn: &'a T) -> Result<(), T::Error>

Set the cursor after the last element, so that Self::next returns None, and Self::prev returns the last element.

pub fn current<'a, T: LoadPage>( &mut self, txn: &'a T ) -> Result<Option<(&'a K, &'a V)>, T::Error>

Return the current position of the cursor.

pub fn next<'a, T: LoadPage>( &mut self, txn: &'a T ) -> Result<Option<(&'a K, &'a V)>, T::Error>

Return the current position of the cursor, and move the cursor to the next position.

pub fn prev<'a, T: LoadPage>( &mut self, txn: &'a T ) -> Result<Option<(&'a K, &'a V)>, T::Error>

Move the cursor to the previous entry, and return the entry that was current before the move. If the cursor is initially after all the entries, this moves it back by two steps.

Trait Implementations

impl<K: Debug + ?Sized, V: Debug + ?Sized, P: Debug + BTreePage<K, V>> Debug for Cursor<K, V, P>

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

Formats the value using the given formatter.