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//! A map based on a splay tree. use std; use std::mem; use std::borrow::Borrow; use tree_core; use iter; /// A map based on a splay tree. /// /// A splay tree based map is a self-adjusting data structure. /// It performs insertion, removal and look-up in `O(log n)` amortized time. /// /// It is a logic error for a key to be modified in such a way that /// the key's ordering relative to any other key, /// as determined by the `Ord` trait, changes while it is in the map. /// This is normally only possible through `Cell`, `RefCell`, global state, I/O, or unsafe code. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// /// map.insert("foo", 1); /// map.insert("bar", 2); /// map.insert("baz", 3); /// /// assert_eq!(map.get("foo"), Some(&1)); /// assert_eq!(map.remove("foo"), Some(1)); /// assert_eq!(map.get("foo"), None); /// /// for (k, v) in &map { /// println!("{}: {}", k, v); /// } /// ``` /// /// `SplayMap` implements an [Entry API](#method.entry) which allows for /// more complex methods of getting, setting, updating and removing keys and their values: /// ``` /// extern crate rand; /// extern crate splay_tree; /// /// use splay_tree::SplayMap; /// /// # fn main() { /// let mut count = SplayMap::new(); /// for _ in 0..1000 { /// let k = rand::random::<u8>(); /// *count.entry(k).or_insert(0) += 1; /// } /// for k in 0..0x100 { /// println!("{}: {}", k, count.get(&k).unwrap_or(&0)); /// } /// # } /// ``` #[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)] #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))] pub struct SplayMap<K, V> { tree: tree_core::Tree<K, V>, } impl<K, V> SplayMap<K, V> where K: Ord, { /// Makes a new empty `SplayMap`. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert("foo", 1); /// assert_eq!(map.len(), 1); /// ``` pub fn new() -> Self { SplayMap { tree: tree_core::Tree::new(), } } /// Clears the map, removing all values. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert("foo", 1); /// map.clear(); /// assert!(map.is_empty()); /// ``` pub fn clear(&mut self) { self.tree = tree_core::Tree::new(); } /// Returns true if the map contains a value for the specified key. /// /// The key may be any borrowed form of the map's key type, /// but the ordering on the borrowed form _must_ match the ordering on the key type. /// /// # Notice /// /// Because `SplayMap` is a self-adjusting amortized data structure, /// this function requires the `mut` qualifier for `self`. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert("foo", 1); /// assert!(map.contains_key("foo")); /// assert!(!map.contains_key("bar")); /// ``` pub fn contains_key<Q: ?Sized>(&mut self, key: &Q) -> bool where K: Borrow<Q>, Q: Ord, { self.tree.contains_key(key) } /// Returns a reference to the value corresponding to the key. /// /// The key may be any borrowed form of the map's key type, /// but the ordering on the borrowed form _must_ match the ordering on the key type. /// /// # Notice /// /// Because `SplayMap` is a self-adjusting amortized data structure, /// this function requires the `mut` qualifier for `self`. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert("foo", 1); /// assert_eq!(map.get("foo"), Some(&1)); /// assert_eq!(map.get("bar"), None); /// ``` pub fn get<Q: ?Sized>(&mut self, key: &Q) -> Option<&V> where K: Borrow<Q>, Q: Ord, { self.get_mut(key).map(|v| &*v) } /// Returns a mutable reference to the value corresponding to the key. /// /// The key may be any borrowed form of the map's key type, /// but the ordering on the borrowed form _must_ match the ordering on the key type. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert("foo", 1); /// map.get_mut("foo").map(|v| *v = 2); /// assert_eq!(map.get("foo"), Some(&2)); /// ``` pub fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V> where K: Borrow<Q>, Q: Ord, { self.tree.get(key) } /// Finds a minimum key which satisfies "greater than or equal to `key`" condition in the map. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert(1, ()); /// map.insert(3, ()); /// /// assert_eq!(map.find_lower_bound_key(&0), Some(&1)); /// assert_eq!(map.find_lower_bound_key(&1), Some(&1)); /// assert_eq!(map.find_lower_bound_key(&4), None); /// ``` pub fn find_lower_bound_key<Q: ?Sized>(&mut self, key: &Q) -> Option<&K> where K: Borrow<Q>, Q: Ord, { self.tree.find_lower_bound(key) } /// Finds a minimum key which satisfies "greater than `key`" condition in the map. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert(1, ()); /// map.insert(3, ()); /// /// assert_eq!(map.find_upper_bound_key(&0), Some(&1)); /// assert_eq!(map.find_upper_bound_key(&1), Some(&3)); /// assert_eq!(map.find_upper_bound_key(&4), None); /// ``` pub fn find_upper_bound_key<Q: ?Sized>(&mut self, key: &Q) -> Option<&K> where K: Borrow<Q>, Q: Ord, { self.tree.find_upper_bound(key) } /// Gets the entry which have the minimum key in the map. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert(1, ()); /// map.insert(3, ()); /// /// assert_eq!(map.smallest(), Some((&1, &()))); /// ``` pub fn smallest(&mut self) -> Option<(&K, &V)> { self.tree.get_lftmost() } /// Takes the entry which have the minimum key in the map. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert(1, ()); /// map.insert(3, ()); /// /// assert_eq!(map.take_smallest(), Some((1, ()))); /// assert_eq!(map.take_smallest(), Some((3, ()))); /// assert_eq!(map.take_smallest(), None); /// ``` pub fn take_smallest(&mut self) -> Option<(K, V)> { self.tree.take_lftmost() } /// Gets the entry which have the maximum key in the map. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert(1, ()); /// map.insert(3, ()); /// /// assert_eq!(map.largest(), Some((&3, &()))); /// ``` pub fn largest(&mut self) -> Option<(&K, &V)> { self.tree.get_rgtmost() } /// Takes the entry which have the maximum key in the map. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert(1, ()); /// map.insert(3, ()); /// /// assert_eq!(map.take_largest(), Some((3, ()))); /// assert_eq!(map.take_largest(), Some((1, ()))); /// assert_eq!(map.take_largest(), None); /// ``` pub fn take_largest(&mut self) -> Option<(K, V)> { self.tree.take_rgtmost() } /// Inserts a key-value pair into the map. /// /// If the map did not have this key present, `None` is returned. /// /// If the map did have this key present, the value is updated, /// and the old value is returned. /// The key is not updated, though; /// this matters for types that can be `==` without being identical. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// assert_eq!(map.insert("foo", 1), None); /// assert_eq!(map.get("foo"), Some(&1)); /// assert_eq!(map.insert("foo", 2), Some(1)); /// assert_eq!(map.get("foo"), Some(&2)); /// ``` pub fn insert(&mut self, key: K, value: V) -> Option<V> { self.tree.insert(key, value) } /// Removes a key from the map, /// returning the value at the key if the key was previously in the map. /// /// The key may be any borrowed form of the map's key type, /// but the ordering on the borrowed form _must_ match the ordering on the key type. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert("foo", 1); /// assert_eq!(map.remove("foo"), Some(1)); /// assert_eq!(map.remove("foo"), None); /// ``` pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V> where K: Borrow<Q>, Q: Ord, { self.tree.remove(key) } /// Gets the given key's corresponding entry in the map for in-place manipulation. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut count = SplayMap::new(); /// /// // count the number of occurrences of letters in the vec /// for x in vec!["a", "b", "a", "c", "a", "b"] { /// *count.entry(x).or_insert(0) += 1; /// } /// /// assert_eq!(count.get("a"), Some(&3)); /// ``` pub fn entry(&mut self, key: K) -> Entry<K, V> { if self.contains_key(&key) { Entry::Occupied(OccupiedEntry { tree: &mut self.tree, }) } else { Entry::Vacant(VacantEntry { key: key, tree: &mut self.tree, }) } } } impl<K, V> SplayMap<K, V> { /// Returns the number of elements in the map. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// map.insert("foo", 1); /// map.insert("bar", 2); /// assert_eq!(map.len(), 2); /// ``` pub fn len(&self) -> usize { self.tree.len() } /// Returns true if the map contains no elements. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map = SplayMap::new(); /// assert!(map.is_empty()); /// /// map.insert("foo", 1); /// assert!(!map.is_empty()); /// /// map.clear(); /// assert!(map.is_empty()); /// ``` pub fn is_empty(&self) -> bool { self.len() == 0 } /// Gets an iterator over the entries of the map, sorted by key. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let map: SplayMap<_, _> = /// vec![("foo", 1), ("bar", 2), ("baz", 3)].into_iter().collect(); /// assert_eq!(vec![(&"bar", &2), (&"baz", &3), (&"foo", &1)], /// map.iter().collect::<Vec<_>>()); /// ``` pub fn iter(&self) -> Iter<K, V> { Iter::new(&self.tree) } /// Gets a mutable iterator over the entries of the map, soretd by key. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map: SplayMap<_, _> = /// vec![("foo", 1), ("bar", 2), ("baz", 3)].into_iter().collect(); /// for (_, v) in map.iter_mut() { /// *v += 10; /// } /// assert_eq!(map.get("bar"), Some(&12)); /// ``` pub fn iter_mut(&mut self) -> IterMut<K, V> { IterMut::new(&mut self.tree) } /// Gets an iterator over the keys of the map, in sorted order. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let map: SplayMap<_, _> = /// vec![("foo", 1), ("bar", 2), ("baz", 3)].into_iter().collect(); /// assert_eq!(vec!["bar", "baz", "foo"], /// map.keys().cloned().collect::<Vec<_>>()); /// ``` pub fn keys(&self) -> Keys<K, V> { Keys::new(&self.tree) } /// Gets an iterator over the values of the map, in order by key. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let map: SplayMap<_, _> = /// vec![("foo", 1), ("bar", 2), ("baz", 3)].into_iter().collect(); /// assert_eq!(vec![2, 3, 1], /// map.values().cloned().collect::<Vec<_>>()); /// ``` pub fn values(&self) -> Values<K, V> { Values::new(&self.tree) } /// Gets a mutable iterator over the values of the map, in order by key. /// /// # Examples /// ``` /// use splay_tree::SplayMap; /// /// let mut map: SplayMap<_, _> = /// vec![("foo", 1), ("bar", 2), ("baz", 3)].into_iter().collect(); /// for v in map.values_mut() { /// *v += 10; /// } /// assert_eq!(vec![12, 13, 11], /// map.values().cloned().collect::<Vec<_>>()); /// ``` pub fn values_mut(&mut self) -> ValuesMut<K, V> { ValuesMut::new(&mut self.tree) } } impl<K, V> Default for SplayMap<K, V> where K: Ord, { fn default() -> Self { SplayMap::new() } } impl<K, V> std::iter::FromIterator<(K, V)> for SplayMap<K, V> where K: Ord, { fn from_iter<I>(iter: I) -> Self where I: IntoIterator<Item = (K, V)>, { let mut map = SplayMap::new(); for (k, v) in iter { map.insert(k, v); } map } } impl<'a, K, V> IntoIterator for &'a SplayMap<K, V> where K: 'a, V: 'a, { type Item = (&'a K, &'a V); type IntoIter = Iter<'a, K, V>; fn into_iter(self) -> Self::IntoIter { Iter::new(&self.tree) } } impl<'a, K, V> IntoIterator for &'a mut SplayMap<K, V> where K: 'a, V: 'a, { type Item = (&'a K, &'a mut V); type IntoIter = IterMut<'a, K, V>; fn into_iter(self) -> Self::IntoIter { IterMut::new(&mut self.tree) } } impl<K, V> IntoIterator for SplayMap<K, V> { type Item = (K, V); type IntoIter = IntoIter<K, V>; fn into_iter(self) -> Self::IntoIter { IntoIter::new(self.tree) } } impl<K, V> Extend<(K, V)> for SplayMap<K, V> where K: Ord, { fn extend<T>(&mut self, iter: T) where T: IntoIterator<Item = (K, V)>, { for (k, v) in iter { self.insert(k, v); } } } impl<'a, K, V> Extend<(&'a K, &'a V)> for SplayMap<K, V> where K: 'a + Copy + Ord, V: 'a + Copy, { fn extend<T>(&mut self, iter: T) where T: IntoIterator<Item = (&'a K, &'a V)>, { for (k, v) in iter { self.insert(*k, *v); } } } /// An iterator over a SplayMap's entries. pub struct Iter<'a, K: 'a, V: 'a>(iter::Iter<'a, K, V>); impl<'a, K: 'a, V: 'a> Iter<'a, K, V> { fn new(tree: &'a tree_core::Tree<K, V>) -> Self { Iter(tree.iter()) } } impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> { type Item = (&'a K, &'a V); fn next(&mut self) -> Option<Self::Item> { self.0.next() } } /// A mutable iterator over a SplayMap's entries. pub struct IterMut<'a, K: 'a, V: 'a>(iter::IterMut<'a, K, V>); impl<'a, K: 'a, V: 'a> IterMut<'a, K, V> { fn new(tree: &'a mut tree_core::Tree<K, V>) -> Self { IterMut(tree.iter_mut()) } } impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> { type Item = (&'a K, &'a mut V); fn next(&mut self) -> Option<Self::Item> { self.0.next() } } /// An owning iterator over a SplayMap's entries. pub struct IntoIter<K, V>(iter::IntoIter<K, V>); impl<K, V> IntoIter<K, V> { fn new(tree: tree_core::Tree<K, V>) -> Self { IntoIter(tree.into_iter()) } } impl<K, V> Iterator for IntoIter<K, V> { type Item = (K, V); fn next(&mut self) -> Option<Self::Item> { self.0.next() } } /// An iterator over a SplayMap's keys. pub struct Keys<'a, K: 'a, V: 'a>(Iter<'a, K, V>); impl<'a, K: 'a, V: 'a> Keys<'a, K, V> { fn new(tree: &'a tree_core::Tree<K, V>) -> Self { Keys(Iter::new(tree)) } } impl<'a, K: 'a, V: 'a> Iterator for Keys<'a, K, V> { type Item = &'a K; fn next(&mut self) -> Option<Self::Item> { self.0.next().map(|(k, _)| k) } } /// An iterator over a SplayMap's values. pub struct Values<'a, K: 'a, V: 'a>(Iter<'a, K, V>); impl<'a, K: 'a, V: 'a> Values<'a, K, V> { fn new(tree: &'a tree_core::Tree<K, V>) -> Self { Values(Iter::new(tree)) } } impl<'a, K: 'a, V: 'a> Iterator for Values<'a, K, V> { type Item = &'a V; fn next(&mut self) -> Option<Self::Item> { self.0.next().map(|(_, v)| v) } } /// A mutable iterator over a SplayMap's values. pub struct ValuesMut<'a, K: 'a, V: 'a>(IterMut<'a, K, V>); impl<'a, K: 'a, V: 'a> ValuesMut<'a, K, V> { fn new(tree: &'a mut tree_core::Tree<K, V>) -> Self { ValuesMut(IterMut::new(tree)) } } impl<'a, K: 'a, V: 'a> Iterator for ValuesMut<'a, K, V> { type Item = &'a mut V; fn next(&mut self) -> Option<Self::Item> { self.0.next().map(|(_, v)| v) } } /// A view into a single entry in a map, which may either be vacant or occupied. pub enum Entry<'a, K: 'a, V: 'a> { /// An occupied entry Occupied(OccupiedEntry<'a, K, V>), /// A vacant entry Vacant(VacantEntry<'a, K, V>), } impl<'a, K: 'a, V: 'a> Entry<'a, K, V> where K: Ord, { /// Returns a reference to this entry's key. pub fn key(&self) -> &K { match *self { Entry::Occupied(ref e) => e.key(), Entry::Vacant(ref e) => e.key(), } } /// Ensures a value is in the entry by inserting the default if empty, /// and returns a mutable reference to the value in the entry. pub fn or_insert(self, default: V) -> &'a mut V { match self { Entry::Occupied(e) => e.into_mut(), Entry::Vacant(e) => e.insert(default), } } /// Ensures a value is in the entry by inserting the result of the default function if empty, /// and returns a mutable reference to the value in the entry. pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V { match self { Entry::Occupied(e) => e.into_mut(), Entry::Vacant(e) => e.insert(default()), } } } /// An occupied Entry. pub struct OccupiedEntry<'a, K: 'a, V: 'a> { tree: &'a mut tree_core::Tree<K, V>, } impl<'a, K: 'a, V: 'a> OccupiedEntry<'a, K, V> where K: Ord, { /// Gets a reference to the key in the entry. pub fn key(&self) -> &K { &self.tree.root_ref().key } /// Gets a reference to the value in the entry. pub fn get(&self) -> &V { &self.tree.root_ref().val } /// Gets a mutable reference to the value in the entry. pub fn get_mut(&mut self) -> &mut V { &mut self.tree.root_mut().val } /// Converts the entry into a mutable reference to its value. pub fn into_mut(self) -> &'a mut V { &mut self.tree.root_mut().val } /// Sets the value of the entry with the OccupiedEntry's key, /// and returns the entry's old value. pub fn insert(&mut self, value: V) -> V { mem::replace(self.get_mut(), value) } /// Takes the value of the entry out of the map, and returns it. pub fn remove(self) -> V { self.tree.pop_root().unwrap().1 } } /// A vacant Entry. pub struct VacantEntry<'a, K: 'a, V: 'a> { key: K, tree: &'a mut tree_core::Tree<K, V>, } impl<'a, K: 'a, V: 'a> VacantEntry<'a, K, V> where K: Ord, { /// Gets a reference to the key that would be used /// when inserting a value through the VacantEntry. pub fn key(&self) -> &K { &self.key } /// Sets the value of the entry with the VacantEntry's key, /// and returns a mutable reference to it. pub fn insert(self, value: V) -> &'a mut V { self.tree.insert(self.key, value); &mut self.tree.root_mut().val } }