diff options
Diffstat (limited to 'src/liballoc/collections/btree')
| -rw-r--r-- | src/liballoc/collections/btree/map.rs | 2860 | ||||
| -rw-r--r-- | src/liballoc/collections/btree/mod.rs | 27 | ||||
| -rw-r--r-- | src/liballoc/collections/btree/navigate.rs | 261 | ||||
| -rw-r--r-- | src/liballoc/collections/btree/node.rs | 1488 | ||||
| -rw-r--r-- | src/liballoc/collections/btree/search.rs | 83 | ||||
| -rw-r--r-- | src/liballoc/collections/btree/set.rs | 1574 |
6 files changed, 0 insertions, 6293 deletions
diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs deleted file mode 100644 index 24d1f61fa68..00000000000 --- a/src/liballoc/collections/btree/map.rs +++ /dev/null @@ -1,2860 +0,0 @@ -use core::borrow::Borrow; -use core::cmp::Ordering; -use core::fmt::Debug; -use core::hash::{Hash, Hasher}; -use core::iter::{FromIterator, FusedIterator, Peekable}; -use core::marker::PhantomData; -use core::mem::{self, ManuallyDrop}; -use core::ops::Bound::{Excluded, Included, Unbounded}; -use core::ops::{Index, RangeBounds}; -use core::{fmt, ptr}; - -use super::node::{self, marker, ForceResult::*, Handle, InsertResult::*, NodeRef}; -use super::search::{self, SearchResult::*}; -use super::unwrap_unchecked; - -use Entry::*; -use UnderflowResult::*; - -/// A map based on a B-Tree. -/// -/// B-Trees represent a fundamental compromise between cache-efficiency and actually minimizing -/// the amount of work performed in a search. In theory, a binary search tree (BST) is the optimal -/// choice for a sorted map, as a perfectly balanced BST performs the theoretical minimum amount of -/// comparisons necessary to find an element (log<sub>2</sub>n). However, in practice the way this -/// is done is *very* inefficient for modern computer architectures. In particular, every element -/// is stored in its own individually heap-allocated node. This means that every single insertion -/// triggers a heap-allocation, and every single comparison should be a cache-miss. Since these -/// are both notably expensive things to do in practice, we are forced to at very least reconsider -/// the BST strategy. -/// -/// A B-Tree instead makes each node contain B-1 to 2B-1 elements in a contiguous array. By doing -/// this, we reduce the number of allocations by a factor of B, and improve cache efficiency in -/// searches. However, this does mean that searches will have to do *more* comparisons on average. -/// The precise number of comparisons depends on the node search strategy used. For optimal cache -/// efficiency, one could search the nodes linearly. For optimal comparisons, one could search -/// the node using binary search. As a compromise, one could also perform a linear search -/// that initially only checks every i<sup>th</sup> element for some choice of i. -/// -/// Currently, our implementation simply performs naive linear search. This provides excellent -/// performance on *small* nodes of elements which are cheap to compare. However in the future we -/// would like to further explore choosing the optimal search strategy based on the choice of B, -/// and possibly other factors. Using linear search, searching for a random element is expected -/// to take O(B * log(n)) comparisons, which is generally worse than a BST. In practice, -/// however, performance is excellent. -/// -/// 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. -/// -/// [`Ord`]: core::cmp::Ord -/// [`Cell`]: core::cell::Cell -/// [`RefCell`]: core::cell::RefCell -/// -/// # Examples -/// -/// ``` -/// use std::collections::BTreeMap; -/// -/// // type inference lets us omit an explicit type signature (which -/// // would be `BTreeMap<&str, &str>` in this example). -/// let mut movie_reviews = BTreeMap::new(); -/// -/// // review some movies. -/// movie_reviews.insert("Office Space", "Deals with real issues in the workplace."); -/// movie_reviews.insert("Pulp Fiction", "Masterpiece."); -/// movie_reviews.insert("The Godfather", "Very enjoyable."); -/// movie_reviews.insert("The Blues Brothers", "Eye lyked it a lot."); -/// -/// // check for a specific one. -/// if !movie_reviews.contains_key("Les Misérables") { -/// println!("We've got {} reviews, but Les Misérables ain't one.", -/// movie_reviews.len()); -/// } -/// -/// // oops, this review has a lot of spelling mistakes, let's delete it. -/// movie_reviews.remove("The Blues Brothers"); -/// -/// // look up the values associated with some keys. -/// let to_find = ["Up!", "Office Space"]; -/// for movie in &to_find { -/// match movie_reviews.get(movie) { -/// Some(review) => println!("{}: {}", movie, review), -/// None => println!("{} is unreviewed.", movie) -/// } -/// } -/// -/// // Look up the value for a key (will panic if the key is not found). -/// println!("Movie review: {}", movie_reviews["Office Space"]); -/// -/// // iterate over everything. -/// for (movie, review) in &movie_reviews { -/// println!("{}: \"{}\"", movie, review); -/// } -/// ``` -/// -/// `BTreeMap` also implements an [`Entry API`](#method.entry), which allows -/// for more complex methods of getting, setting, updating and removing keys and -/// their values: -/// -/// ``` -/// use std::collections::BTreeMap; -/// -/// // type inference lets us omit an explicit type signature (which -/// // would be `BTreeMap<&str, u8>` in this example). -/// let mut player_stats = BTreeMap::new(); -/// -/// fn random_stat_buff() -> u8 { -/// // could actually return some random value here - let's just return -/// // some fixed value for now -/// 42 -/// } -/// -/// // insert a key only if it doesn't already exist -/// player_stats.entry("health").or_insert(100); -/// -/// // insert a key using a function that provides a new value only if it -/// // doesn't already exist -/// player_stats.entry("defence").or_insert_with(random_stat_buff); -/// -/// // update a key, guarding against the key possibly not being set -/// let stat = player_stats.entry("attack").or_insert(100); -/// *stat += random_stat_buff(); -/// ``` -#[stable(feature = "rust1", since = "1.0.0")] -pub struct BTreeMap<K, V> { - root: Option<node::Root<K, V>>, - length: usize, -} - -#[stable(feature = "btree_drop", since = "1.7.0")] -unsafe impl<#[may_dangle] K, #[may_dangle] V> Drop for BTreeMap<K, V> { - fn drop(&mut self) { - unsafe { - drop(ptr::read(self).into_iter()); - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> { - fn clone(&self) -> BTreeMap<K, V> { - fn clone_subtree<'a, K: Clone, V: Clone>( - node: node::NodeRef<marker::Immut<'a>, K, V, marker::LeafOrInternal>, - ) -> BTreeMap<K, V> - where - K: 'a, - V: 'a, - { - match node.force() { - Leaf(leaf) => { - let mut out_tree = BTreeMap { root: Some(node::Root::new_leaf()), length: 0 }; - - { - let root = out_tree.root.as_mut().unwrap(); // unwrap succeeds because we just wrapped - let mut out_node = match root.as_mut().force() { - Leaf(leaf) => leaf, - Internal(_) => unreachable!(), - }; - - let mut in_edge = leaf.first_edge(); - while let Ok(kv) = in_edge.right_kv() { - let (k, v) = kv.into_kv(); - in_edge = kv.right_edge(); - - out_node.push(k.clone(), v.clone()); - out_tree.length += 1; - } - } - - out_tree - } - Internal(internal) => { - let mut out_tree = clone_subtree(internal.first_edge().descend()); - - { - let out_root = BTreeMap::ensure_is_owned(&mut out_tree.root); - let mut out_node = out_root.push_level(); - let mut in_edge = internal.first_edge(); - while let Ok(kv) = in_edge.right_kv() { - let (k, v) = kv.into_kv(); - in_edge = kv.right_edge(); - - let k = (*k).clone(); - let v = (*v).clone(); - let subtree = clone_subtree(in_edge.descend()); - - // We can't destructure subtree directly - // because BTreeMap implements Drop - let (subroot, sublength) = unsafe { - let subtree = ManuallyDrop::new(subtree); - let root = ptr::read(&subtree.root); - let length = subtree.length; - (root, length) - }; - - out_node.push(k, v, subroot.unwrap_or_else(node::Root::new_leaf)); - out_tree.length += 1 + sublength; - } - } - - out_tree - } - } - } - - if self.is_empty() { - // Ideally we'd call `BTreeMap::new` here, but that has the `K: - // Ord` constraint, which this method lacks. - BTreeMap { root: None, length: 0 } - } else { - clone_subtree(self.root.as_ref().unwrap().as_ref()) // unwrap succeeds because not empty - } - } -} - -impl<K, Q: ?Sized> super::Recover<Q> for BTreeMap<K, ()> -where - K: Borrow<Q> + Ord, - Q: Ord, -{ - type Key = K; - - fn get(&self, key: &Q) -> Option<&K> { - match search::search_tree(self.root.as_ref()?.as_ref(), key) { - Found(handle) => Some(handle.into_kv().0), - GoDown(_) => None, - } - } - - fn take(&mut self, key: &Q) -> Option<K> { - match search::search_tree(self.root.as_mut()?.as_mut(), key) { - Found(handle) => Some( - OccupiedEntry { handle, length: &mut self.length, _marker: PhantomData } - .remove_kv() - .0, - ), - GoDown(_) => None, - } - } - - fn replace(&mut self, key: K) -> Option<K> { - let root = Self::ensure_is_owned(&mut self.root); - match search::search_tree::<marker::Mut<'_>, K, (), K>(root.as_mut(), &key) { - Found(handle) => Some(mem::replace(handle.into_kv_mut().0, key)), - GoDown(handle) => { - VacantEntry { key, handle, length: &mut self.length, _marker: PhantomData } - .insert(()); - None - } - } - } -} - -/// An iterator over the entries of a `BTreeMap`. -/// -/// This `struct` is created by the [`iter`] method on [`BTreeMap`]. See its -/// documentation for more. -/// -/// [`iter`]: BTreeMap::iter -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Iter<'a, K: 'a, V: 'a> { - range: Range<'a, K, V>, - length: usize, -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Iter<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -/// A mutable iterator over the entries of a `BTreeMap`. -/// -/// This `struct` is created by the [`iter_mut`] method on [`BTreeMap`]. See its -/// documentation for more. -/// -/// [`iter_mut`]: BTreeMap::iter_mut -#[stable(feature = "rust1", since = "1.0.0")] -#[derive(Debug)] -pub struct IterMut<'a, K: 'a, V: 'a> { - range: RangeMut<'a, K, V>, - length: usize, -} - -/// An owning iterator over the entries of a `BTreeMap`. -/// -/// This `struct` is created by the [`into_iter`] method on [`BTreeMap`] -/// (provided by the `IntoIterator` trait). See its documentation for more. -/// -/// [`into_iter`]: IntoIterator::into_iter -#[stable(feature = "rust1", since = "1.0.0")] -pub struct IntoIter<K, V> { - front: Option<Handle<NodeRef<marker::Owned, K, V, marker::Leaf>, marker::Edge>>, - back: Option<Handle<NodeRef<marker::Owned, K, V, marker::Leaf>, marker::Edge>>, - length: usize, -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IntoIter<K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let range = Range { - front: self.front.as_ref().map(|f| f.reborrow()), - back: self.back.as_ref().map(|b| b.reborrow()), - }; - f.debug_list().entries(range).finish() - } -} - -/// An iterator over the keys of a `BTreeMap`. -/// -/// This `struct` is created by the [`keys`] method on [`BTreeMap`]. See its -/// documentation for more. -/// -/// [`keys`]: BTreeMap::keys -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Keys<'a, K: 'a, V: 'a> { - inner: Iter<'a, K, V>, -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<K: fmt::Debug, V> fmt::Debug for Keys<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -/// An iterator over the values of a `BTreeMap`. -/// -/// This `struct` is created by the [`values`] method on [`BTreeMap`]. See its -/// documentation for more. -/// -/// [`values`]: BTreeMap::values -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Values<'a, K: 'a, V: 'a> { - inner: Iter<'a, K, V>, -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<K, V: fmt::Debug> fmt::Debug for Values<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -/// A mutable iterator over the values of a `BTreeMap`. -/// -/// This `struct` is created by the [`values_mut`] method on [`BTreeMap`]. See its -/// documentation for more. -/// -/// [`values_mut`]: BTreeMap::values_mut -#[stable(feature = "map_values_mut", since = "1.10.0")] -#[derive(Debug)] -pub struct ValuesMut<'a, K: 'a, V: 'a> { - inner: IterMut<'a, K, V>, -} - -/// An iterator over a sub-range of entries in a `BTreeMap`. -/// -/// This `struct` is created by the [`range`] method on [`BTreeMap`]. See its -/// documentation for more. -/// -/// [`range`]: BTreeMap::range -#[stable(feature = "btree_range", since = "1.17.0")] -pub struct Range<'a, K: 'a, V: 'a> { - front: Option<Handle<NodeRef<marker::Immut<'a>, K, V, marker::Leaf>, marker::Edge>>, - back: Option<Handle<NodeRef<marker::Immut<'a>, K, V, marker::Leaf>, marker::Edge>>, -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Range<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -/// A mutable iterator over a sub-range of entries in a `BTreeMap`. -/// -/// This `struct` is created by the [`range_mut`] method on [`BTreeMap`]. See its -/// documentation for more. -/// -/// [`range_mut`]: BTreeMap::range_mut -#[stable(feature = "btree_range", since = "1.17.0")] -pub struct RangeMut<'a, K: 'a, V: 'a> { - front: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>, - back: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>, - - // Be invariant in `K` and `V` - _marker: PhantomData<&'a mut (K, V)>, -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for RangeMut<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let range = Range { - front: self.front.as_ref().map(|f| f.reborrow()), - back: self.back.as_ref().map(|b| b.reborrow()), - }; - f.debug_list().entries(range).finish() - } -} - -/// A view into a single entry in a map, which may either be vacant or occupied. -/// -/// This `enum` is constructed from the [`entry`] method on [`BTreeMap`]. -/// -/// [`entry`]: BTreeMap::entry -#[stable(feature = "rust1", since = "1.0.0")] -pub enum Entry<'a, K: 'a, V: 'a> { - /// A vacant entry. - #[stable(feature = "rust1", since = "1.0.0")] - Vacant(#[stable(feature = "rust1", since = "1.0.0")] VacantEntry<'a, K, V>), - - /// An occupied entry. - #[stable(feature = "rust1", since = "1.0.0")] - Occupied(#[stable(feature = "rust1", since = "1.0.0")] OccupiedEntry<'a, K, V>), -} - -#[stable(feature = "debug_btree_map", since = "1.12.0")] -impl<K: Debug + Ord, V: Debug> Debug for Entry<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - match *self { - Vacant(ref v) => f.debug_tuple("Entry").field(v).finish(), - Occupied(ref o) => f.debug_tuple("Entry").field(o).finish(), - } - } -} - -/// A view into a vacant entry in a `BTreeMap`. -/// It is part of the [`Entry`] enum. -/// -/// [`Entry`]: enum.Entry.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct VacantEntry<'a, K: 'a, V: 'a> { - key: K, - handle: Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>, - length: &'a mut usize, - - // Be invariant in `K` and `V` - _marker: PhantomData<&'a mut (K, V)>, -} - -#[stable(feature = "debug_btree_map", since = "1.12.0")] -impl<K: Debug + Ord, V> Debug for VacantEntry<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("VacantEntry").field(self.key()).finish() - } -} - -/// A view into an occupied entry in a `BTreeMap`. -/// It is part of the [`Entry`] enum. -/// -/// [`Entry`]: enum.Entry.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct OccupiedEntry<'a, K: 'a, V: 'a> { - handle: Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::KV>, - - length: &'a mut usize, - - // Be invariant in `K` and `V` - _marker: PhantomData<&'a mut (K, V)>, -} - -#[stable(feature = "debug_btree_map", since = "1.12.0")] -impl<K: Debug + Ord, V: Debug> Debug for OccupiedEntry<'_, K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_struct("OccupiedEntry").field("key", self.key()).field("value", self.get()).finish() - } -} - -// An iterator for merging two sorted sequences into one -struct MergeIter<K, V, I: Iterator<Item = (K, V)>> { - left: Peekable<I>, - right: Peekable<I>, -} - -impl<K: Ord, V> BTreeMap<K, V> { - /// Makes a new empty BTreeMap. - /// - /// Does not allocate anything on its own. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// - /// // entries can now be inserted into the empty map - /// map.insert(1, "a"); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")] - pub const fn new() -> BTreeMap<K, V> { - BTreeMap { root: None, length: 0 } - } - - /// Clears the map, removing all elements. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "a"); - /// a.clear(); - /// assert!(a.is_empty()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn clear(&mut self) { - *self = BTreeMap::new(); - } - - /// 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. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.get(&1), Some(&"a")); - /// assert_eq!(map.get(&2), None); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn get<Q: ?Sized>(&self, key: &Q) -> Option<&V> - where - K: Borrow<Q>, - Q: Ord, - { - match search::search_tree(self.root.as_ref()?.as_ref(), key) { - Found(handle) => Some(handle.into_kv().1), - GoDown(_) => None, - } - } - - /// Returns the key-value pair corresponding to the supplied key. - /// - /// The supplied 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 std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.get_key_value(&1), Some((&1, &"a"))); - /// assert_eq!(map.get_key_value(&2), None); - /// ``` - #[stable(feature = "map_get_key_value", since = "1.40.0")] - pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)> - where - K: Borrow<Q>, - Q: Ord, - { - match search::search_tree(self.root.as_ref()?.as_ref(), k) { - Found(handle) => Some(handle.into_kv()), - GoDown(_) => None, - } - } - - /// Returns the first key-value pair in the map. - /// The key in this pair is the minimum key in the map. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// assert_eq!(map.first_key_value(), None); - /// map.insert(1, "b"); - /// map.insert(2, "a"); - /// assert_eq!(map.first_key_value(), Some((&1, &"b"))); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn first_key_value(&self) -> Option<(&K, &V)> { - let front = self.root.as_ref()?.as_ref().first_leaf_edge(); - front.right_kv().ok().map(Handle::into_kv) - } - - /// Returns the first entry in the map for in-place manipulation. - /// The key of this entry is the minimum key in the map. - /// - /// # Examples - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// map.insert(2, "b"); - /// if let Some(mut entry) = map.first_entry() { - /// if *entry.key() > 0 { - /// entry.insert("first"); - /// } - /// } - /// assert_eq!(*map.get(&1).unwrap(), "first"); - /// assert_eq!(*map.get(&2).unwrap(), "b"); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn first_entry(&mut self) -> Option<OccupiedEntry<'_, K, V>> { - let front = self.root.as_mut()?.as_mut().first_leaf_edge(); - let kv = front.right_kv().ok()?; - Some(OccupiedEntry { - handle: kv.forget_node_type(), - length: &mut self.length, - _marker: PhantomData, - }) - } - - /// Removes and returns the first element in the map. - /// The key of this element is the minimum key that was in the map. - /// - /// # Examples - /// - /// Draining elements in ascending order, while keeping a usable map each iteration. - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// map.insert(2, "b"); - /// while let Some((key, _val)) = map.pop_first() { - /// assert!(map.iter().all(|(k, _v)| *k > key)); - /// } - /// assert!(map.is_empty()); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn pop_first(&mut self) -> Option<(K, V)> { - self.first_entry().map(|entry| entry.remove_entry()) - } - - /// Returns the last key-value pair in the map. - /// The key in this pair is the maximum key in the map. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "b"); - /// map.insert(2, "a"); - /// assert_eq!(map.last_key_value(), Some((&2, &"a"))); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn last_key_value(&self) -> Option<(&K, &V)> { - let back = self.root.as_ref()?.as_ref().last_leaf_edge(); - back.left_kv().ok().map(Handle::into_kv) - } - - /// Returns the last entry in the map for in-place manipulation. - /// The key of this entry is the maximum key in the map. - /// - /// # Examples - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// map.insert(2, "b"); - /// if let Some(mut entry) = map.last_entry() { - /// if *entry.key() > 0 { - /// entry.insert("last"); - /// } - /// } - /// assert_eq!(*map.get(&1).unwrap(), "a"); - /// assert_eq!(*map.get(&2).unwrap(), "last"); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn last_entry(&mut self) -> Option<OccupiedEntry<'_, K, V>> { - let back = self.root.as_mut()?.as_mut().last_leaf_edge(); - let kv = back.left_kv().ok()?; - Some(OccupiedEntry { - handle: kv.forget_node_type(), - length: &mut self.length, - _marker: PhantomData, - }) - } - - /// Removes and returns the last element in the map. - /// The key of this element is the maximum key that was in the map. - /// - /// # Examples - /// - /// Draining elements in descending order, while keeping a usable map each iteration. - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// map.insert(2, "b"); - /// while let Some((key, _val)) = map.pop_last() { - /// assert!(map.iter().all(|(k, _v)| *k < key)); - /// } - /// assert!(map.is_empty()); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn pop_last(&mut self) -> Option<(K, V)> { - self.last_entry().map(|entry| entry.remove_entry()) - } - - /// 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. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.contains_key(&1), true); - /// assert_eq!(map.contains_key(&2), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool - where - K: Borrow<Q>, - Q: Ord, - { - self.get(key).is_some() - } - - /// 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 - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// if let Some(x) = map.get_mut(&1) { - /// *x = "b"; - /// } - /// assert_eq!(map[&1], "b"); - /// ``` - // See `get` for implementation notes, this is basically a copy-paste with mut's added - #[stable(feature = "rust1", since = "1.0.0")] - pub fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V> - where - K: Borrow<Q>, - Q: Ord, - { - match search::search_tree(self.root.as_mut()?.as_mut(), key) { - Found(handle) => Some(handle.into_kv_mut().1), - GoDown(_) => None, - } - } - - /// 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. See the [module-level - /// documentation] for more. - /// - /// [module-level documentation]: index.html#insert-and-complex-keys - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// assert_eq!(map.insert(37, "a"), None); - /// assert_eq!(map.is_empty(), false); - /// - /// map.insert(37, "b"); - /// assert_eq!(map.insert(37, "c"), Some("b")); - /// assert_eq!(map[&37], "c"); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn insert(&mut self, key: K, value: V) -> Option<V> { - match self.entry(key) { - Occupied(mut entry) => Some(entry.insert(value)), - Vacant(entry) => { - entry.insert(value); - None - } - } - } - - /// 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 - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.remove(&1), Some("a")); - /// assert_eq!(map.remove(&1), None); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V> - where - K: Borrow<Q>, - Q: Ord, - { - self.remove_entry(key).map(|(_, v)| v) - } - - /// Removes a key from the map, returning the stored key and value 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 - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.remove_entry(&1), Some((1, "a"))); - /// assert_eq!(map.remove_entry(&1), None); - /// ``` - #[stable(feature = "btreemap_remove_entry", since = "1.45.0")] - pub fn remove_entry<Q: ?Sized>(&mut self, key: &Q) -> Option<(K, V)> - where - K: Borrow<Q>, - Q: Ord, - { - match search::search_tree(self.root.as_mut()?.as_mut(), key) { - Found(handle) => Some( - OccupiedEntry { handle, length: &mut self.length, _marker: PhantomData } - .remove_entry(), - ), - GoDown(_) => None, - } - } - - /// Moves all elements from `other` into `Self`, leaving `other` empty. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "a"); - /// a.insert(2, "b"); - /// a.insert(3, "c"); - /// - /// let mut b = BTreeMap::new(); - /// b.insert(3, "d"); - /// b.insert(4, "e"); - /// b.insert(5, "f"); - /// - /// a.append(&mut b); - /// - /// assert_eq!(a.len(), 5); - /// assert_eq!(b.len(), 0); - /// - /// assert_eq!(a[&1], "a"); - /// assert_eq!(a[&2], "b"); - /// assert_eq!(a[&3], "d"); - /// assert_eq!(a[&4], "e"); - /// assert_eq!(a[&5], "f"); - /// ``` - #[stable(feature = "btree_append", since = "1.11.0")] - pub fn append(&mut self, other: &mut Self) { - // Do we have to append anything at all? - if other.is_empty() { - return; - } - - // We can just swap `self` and `other` if `self` is empty. - if self.is_empty() { - mem::swap(self, other); - return; - } - - // First, we merge `self` and `other` into a sorted sequence in linear time. - let self_iter = mem::take(self).into_iter(); - let other_iter = mem::take(other).into_iter(); - let iter = MergeIter { left: self_iter.peekable(), right: other_iter.peekable() }; - - // Second, we build a tree from the sorted sequence in linear time. - self.from_sorted_iter(iter); - } - - /// Constructs a double-ended iterator over a sub-range of elements in the map. - /// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will - /// yield elements from min (inclusive) to max (exclusive). - /// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example - /// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive - /// range from 4 to 10. - /// - /// # Panics - /// - /// Panics if range `start > end`. - /// Panics if range `start == end` and both bounds are `Excluded`. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::ops::Bound::Included; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(3, "a"); - /// map.insert(5, "b"); - /// map.insert(8, "c"); - /// for (&key, &value) in map.range((Included(&4), Included(&8))) { - /// println!("{}: {}", key, value); - /// } - /// assert_eq!(Some((&5, &"b")), map.range(4..).next()); - /// ``` - #[stable(feature = "btree_range", since = "1.17.0")] - pub fn range<T: ?Sized, R>(&self, range: R) -> Range<'_, K, V> - where - T: Ord, - K: Borrow<T>, - R: RangeBounds<T>, - { - if let Some(root) = &self.root { - let (f, b) = range_search(root.as_ref(), range); - - Range { front: Some(f), back: Some(b) } - } else { - Range { front: None, back: None } - } - } - - /// Constructs a mutable double-ended iterator over a sub-range of elements in the map. - /// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will - /// yield elements from min (inclusive) to max (exclusive). - /// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example - /// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive - /// range from 4 to 10. - /// - /// # Panics - /// - /// Panics if range `start > end`. - /// Panics if range `start == end` and both bounds are `Excluded`. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, i32> = ["Alice", "Bob", "Carol", "Cheryl"] - /// .iter() - /// .map(|&s| (s, 0)) - /// .collect(); - /// for (_, balance) in map.range_mut("B".."Cheryl") { - /// *balance += 100; - /// } - /// for (name, balance) in &map { - /// println!("{} => {}", name, balance); - /// } - /// ``` - #[stable(feature = "btree_range", since = "1.17.0")] - pub fn range_mut<T: ?Sized, R>(&mut self, range: R) -> RangeMut<'_, K, V> - where - T: Ord, - K: Borrow<T>, - R: RangeBounds<T>, - { - if let Some(root) = &mut self.root { - let (f, b) = range_search(root.as_mut(), range); - - RangeMut { front: Some(f), back: Some(b), _marker: PhantomData } - } else { - RangeMut { front: None, back: None, _marker: PhantomData } - } - } - - /// Gets the given key's corresponding entry in the map for in-place manipulation. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut count: BTreeMap<&str, usize> = BTreeMap::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["a"], 3); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn entry(&mut self, key: K) -> Entry<'_, K, V> { - // FIXME(@porglezomp) Avoid allocating if we don't insert - let root = Self::ensure_is_owned(&mut self.root); - match search::search_tree(root.as_mut(), &key) { - Found(handle) => { - Occupied(OccupiedEntry { handle, length: &mut self.length, _marker: PhantomData }) - } - GoDown(handle) => { - Vacant(VacantEntry { key, handle, length: &mut self.length, _marker: PhantomData }) - } - } - } - - fn from_sorted_iter<I: Iterator<Item = (K, V)>>(&mut self, iter: I) { - let root = Self::ensure_is_owned(&mut self.root); - let mut cur_node = root.as_mut().last_leaf_edge().into_node(); - // Iterate through all key-value pairs, pushing them into nodes at the right level. - for (key, value) in iter { - // Try to push key-value pair into the current leaf node. - if cur_node.len() < node::CAPACITY { - cur_node.push(key, value); - } else { - // No space left, go up and push there. - let mut open_node; - let mut test_node = cur_node.forget_type(); - loop { - match test_node.ascend() { - Ok(parent) => { - let parent = parent.into_node(); - if parent.len() < node::CAPACITY { - // Found a node with space left, push here. - open_node = parent; - break; - } else { - // Go up again. - test_node = parent.forget_type(); - } - } - Err(node) => { - // We are at the top, create a new root node and push there. - open_node = node.into_root_mut().push_level(); - break; - } - } - } - - // Push key-value pair and new right subtree. - let tree_height = open_node.height() - 1; - let mut right_tree = node::Root::new_leaf(); - for _ in 0..tree_height { - right_tree.push_level(); - } - open_node.push(key, value, right_tree); - - // Go down to the right-most leaf again. - cur_node = open_node.forget_type().last_leaf_edge().into_node(); - } - - self.length += 1; - } - Self::fix_right_edge(root) - } - - fn fix_right_edge(root: &mut node::Root<K, V>) { - // Handle underfull nodes, start from the top. - let mut cur_node = root.as_mut(); - while let Internal(internal) = cur_node.force() { - // Check if right-most child is underfull. - let mut last_edge = internal.last_edge(); - let right_child_len = last_edge.reborrow().descend().len(); - if right_child_len < node::MIN_LEN { - // We need to steal. - let mut last_kv = match last_edge.left_kv() { - Ok(left) => left, - Err(_) => unreachable!(), - }; - last_kv.bulk_steal_left(node::MIN_LEN - right_child_len); - last_edge = last_kv.right_edge(); - } - - // Go further down. - cur_node = last_edge.descend(); - } - } - - /// Splits the collection into two at the given key. Returns everything after the given key, - /// including the key. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "a"); - /// a.insert(2, "b"); - /// a.insert(3, "c"); - /// a.insert(17, "d"); - /// a.insert(41, "e"); - /// - /// let b = a.split_off(&3); - /// - /// assert_eq!(a.len(), 2); - /// assert_eq!(b.len(), 3); - /// - /// assert_eq!(a[&1], "a"); - /// assert_eq!(a[&2], "b"); - /// - /// assert_eq!(b[&3], "c"); - /// assert_eq!(b[&17], "d"); - /// assert_eq!(b[&41], "e"); - /// ``` - #[stable(feature = "btree_split_off", since = "1.11.0")] - pub fn split_off<Q: ?Sized + Ord>(&mut self, key: &Q) -> Self - where - K: Borrow<Q>, - { - if self.is_empty() { - return Self::new(); - } - - let total_num = self.len(); - let left_root = self.root.as_mut().unwrap(); // unwrap succeeds because not empty - - let mut right = Self::new(); - let right_root = Self::ensure_is_owned(&mut right.root); - for _ in 0..left_root.height() { - right_root.push_level(); - } - - { - let mut left_node = left_root.as_mut(); - let mut right_node = right_root.as_mut(); - - loop { - let mut split_edge = match search::search_node(left_node, key) { - // key is going to the right tree - Found(handle) => handle.left_edge(), - GoDown(handle) => handle, - }; - - split_edge.move_suffix(&mut right_node); - - match (split_edge.force(), right_node.force()) { - (Internal(edge), Internal(node)) => { - left_node = edge.descend(); - right_node = node.first_edge().descend(); - } - (Leaf(_), Leaf(_)) => { - break; - } - _ => { - unreachable!(); - } - } - } - } - - left_root.fix_right_border(); - right_root.fix_left_border(); - - if left_root.height() < right_root.height() { - self.recalc_length(); - right.length = total_num - self.len(); - } else { - right.recalc_length(); - self.length = total_num - right.len(); - } - - right - } - - /// Creates an iterator which uses a closure to determine if an element should be removed. - /// - /// If the closure returns true, the element is removed from the map and yielded. - /// If the closure returns false, or panics, the element remains in the map and will not be - /// yielded. - /// - /// Note that `drain_filter` lets you mutate every value in the filter closure, regardless of - /// whether you choose to keep or remove it. - /// - /// If the iterator is only partially consumed or not consumed at all, each of the remaining - /// elements will still be subjected to the closure and removed and dropped if it returns true. - /// - /// It is unspecified how many more elements will be subjected to the closure - /// if a panic occurs in the closure, or a panic occurs while dropping an element, - /// or if the `DrainFilter` value is leaked. - /// - /// # Examples - /// - /// Splitting a map into even and odd keys, reusing the original map: - /// - /// ``` - /// #![feature(btree_drain_filter)] - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x)).collect(); - /// let evens: BTreeMap<_, _> = map.drain_filter(|k, _v| k % 2 == 0).collect(); - /// let odds = map; - /// assert_eq!(evens.keys().copied().collect::<Vec<_>>(), vec![0, 2, 4, 6]); - /// assert_eq!(odds.keys().copied().collect::<Vec<_>>(), vec![1, 3, 5, 7]); - /// ``` - #[unstable(feature = "btree_drain_filter", issue = "70530")] - pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, K, V, F> - where - F: FnMut(&K, &mut V) -> bool, - { - DrainFilter { pred, inner: self.drain_filter_inner() } - } - pub(super) fn drain_filter_inner(&mut self) -> DrainFilterInner<'_, K, V> { - let front = self.root.as_mut().map(|r| r.as_mut().first_leaf_edge()); - DrainFilterInner { length: &mut self.length, cur_leaf_edge: front } - } - - /// Calculates the number of elements if it is incorrect. - fn recalc_length(&mut self) { - fn dfs<'a, K, V>(node: NodeRef<marker::Immut<'a>, K, V, marker::LeafOrInternal>) -> usize - where - K: 'a, - V: 'a, - { - let mut res = node.len(); - - if let Internal(node) = node.force() { - let mut edge = node.first_edge(); - loop { - res += dfs(edge.reborrow().descend()); - match edge.right_kv() { - Ok(right_kv) => { - edge = right_kv.right_edge(); - } - Err(_) => { - break; - } - } - } - } - - res - } - - self.length = dfs(self.root.as_ref().unwrap().as_ref()); - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K: 'a, V: 'a> IntoIterator for &'a BTreeMap<K, V> { - type Item = (&'a K, &'a V); - type IntoIter = Iter<'a, K, V>; - - fn into_iter(self) -> Iter<'a, K, V> { - self.iter() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> { - type Item = (&'a K, &'a V); - - fn next(&mut self) -> Option<(&'a K, &'a V)> { - if self.length == 0 { - None - } else { - self.length -= 1; - unsafe { Some(self.range.next_unchecked()) } - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - (self.length, Some(self.length)) - } - - fn last(mut self) -> Option<(&'a K, &'a V)> { - self.next_back() - } - - fn min(mut self) -> Option<(&'a K, &'a V)> { - self.next() - } - - fn max(mut self) -> Option<(&'a K, &'a V)> { - self.next_back() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for Iter<'_, K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K: 'a, V: 'a> DoubleEndedIterator for Iter<'a, K, V> { - fn next_back(&mut self) -> Option<(&'a K, &'a V)> { - if self.length == 0 { - None - } else { - self.length -= 1; - unsafe { Some(self.range.next_back_unchecked()) } - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> ExactSizeIterator for Iter<'_, K, V> { - fn len(&self) -> usize { - self.length - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> Clone for Iter<'_, K, V> { - fn clone(&self) -> Self { - Iter { range: self.range.clone(), length: self.length } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K: 'a, V: 'a> IntoIterator for &'a mut BTreeMap<K, V> { - type Item = (&'a K, &'a mut V); - type IntoIter = IterMut<'a, K, V>; - - fn into_iter(self) -> IterMut<'a, K, V> { - self.iter_mut() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> { - type Item = (&'a K, &'a mut V); - - fn next(&mut self) -> Option<(&'a K, &'a mut V)> { - if self.length == 0 { - None - } else { - self.length -= 1; - let (k, v) = unsafe { self.range.next_unchecked() }; - Some((k, v)) // coerce k from `&mut K` to `&K` - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - (self.length, Some(self.length)) - } - - fn last(mut self) -> Option<(&'a K, &'a mut V)> { - self.next_back() - } - - fn min(mut self) -> Option<(&'a K, &'a mut V)> { - self.next() - } - - fn max(mut self) -> Option<(&'a K, &'a mut V)> { - self.next_back() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K: 'a, V: 'a> DoubleEndedIterator for IterMut<'a, K, V> { - fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> { - if self.length == 0 { - None - } else { - self.length -= 1; - let (k, v) = unsafe { self.range.next_back_unchecked() }; - Some((k, v)) // coerce k from `&mut K` to `&K` - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> ExactSizeIterator for IterMut<'_, K, V> { - fn len(&self) -> usize { - self.length - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for IterMut<'_, K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> IntoIterator for BTreeMap<K, V> { - type Item = (K, V); - type IntoIter = IntoIter<K, V>; - - fn into_iter(self) -> IntoIter<K, V> { - let mut me = ManuallyDrop::new(self); - if let Some(root) = me.root.take() { - let (f, b) = full_range_search(root.into_ref()); - - IntoIter { front: Some(f), back: Some(b), length: me.length } - } else { - IntoIter { front: None, back: None, length: 0 } - } - } -} - -#[stable(feature = "btree_drop", since = "1.7.0")] -impl<K, V> Drop for IntoIter<K, V> { - fn drop(&mut self) { - struct DropGuard<'a, K, V>(&'a mut IntoIter<K, V>); - - impl<'a, K, V> Drop for DropGuard<'a, K, V> { - fn drop(&mut self) { - // Continue the same loop we perform below. This only runs when unwinding, so we - // don't have to care about panics this time (they'll abort). - while let Some(_) = self.0.next() {} - - unsafe { - let mut node = - unwrap_unchecked(ptr::read(&self.0.front)).into_node().forget_type(); - while let Some(parent) = node.deallocate_and_ascend() { - node = parent.into_node().forget_type(); - } - } - } - } - - while let Some(pair) = self.next() { - let guard = DropGuard(self); - drop(pair); - mem::forget(guard); - } - - unsafe { - if let Some(front) = ptr::read(&self.front) { - let mut node = front.into_node().forget_type(); - // Most of the nodes have been deallocated while traversing - // but one pile from a leaf up to the root is left standing. - while let Some(parent) = node.deallocate_and_ascend() { - node = parent.into_node().forget_type(); - } - } - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> Iterator for IntoIter<K, V> { - type Item = (K, V); - - fn next(&mut self) -> Option<(K, V)> { - if self.length == 0 { - None - } else { - self.length -= 1; - Some(unsafe { self.front.as_mut().unwrap().next_unchecked() }) - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - (self.length, Some(self.length)) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> DoubleEndedIterator for IntoIter<K, V> { - fn next_back(&mut self) -> Option<(K, V)> { - if self.length == 0 { - None - } else { - self.length -= 1; - Some(unsafe { self.back.as_mut().unwrap().next_back_unchecked() }) - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> ExactSizeIterator for IntoIter<K, V> { - fn len(&self) -> usize { - self.length - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for IntoIter<K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Iterator for Keys<'a, K, V> { - type Item = &'a K; - - fn next(&mut self) -> Option<&'a K> { - self.inner.next().map(|(k, _)| k) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } - - fn last(mut self) -> Option<&'a K> { - self.next_back() - } - - fn min(mut self) -> Option<&'a K> { - self.next() - } - - fn max(mut self) -> Option<&'a K> { - self.next_back() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> DoubleEndedIterator for Keys<'a, K, V> { - fn next_back(&mut self) -> Option<&'a K> { - self.inner.next_back().map(|(k, _)| k) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> ExactSizeIterator for Keys<'_, K, V> { - fn len(&self) -> usize { - self.inner.len() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for Keys<'_, K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> Clone for Keys<'_, K, V> { - fn clone(&self) -> Self { - Keys { inner: self.inner.clone() } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Iterator for Values<'a, K, V> { - type Item = &'a V; - - fn next(&mut self) -> Option<&'a V> { - self.inner.next().map(|(_, v)| v) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } - - fn last(mut self) -> Option<&'a V> { - self.next_back() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> DoubleEndedIterator for Values<'a, K, V> { - fn next_back(&mut self) -> Option<&'a V> { - self.inner.next_back().map(|(_, v)| v) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> ExactSizeIterator for Values<'_, K, V> { - fn len(&self) -> usize { - self.inner.len() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for Values<'_, K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> Clone for Values<'_, K, V> { - fn clone(&self) -> Self { - Values { inner: self.inner.clone() } - } -} - -/// An iterator produced by calling `drain_filter` on BTreeMap. -#[unstable(feature = "btree_drain_filter", issue = "70530")] -pub struct DrainFilter<'a, K, V, F> -where - K: 'a, - V: 'a, - F: 'a + FnMut(&K, &mut V) -> bool, -{ - pred: F, - inner: DrainFilterInner<'a, K, V>, -} -/// Most of the implementation of DrainFilter, independent of the type -/// of the predicate, thus also serving for BTreeSet::DrainFilter. -pub(super) struct DrainFilterInner<'a, K: 'a, V: 'a> { - length: &'a mut usize, - cur_leaf_edge: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>, -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<K, V, F> Drop for DrainFilter<'_, K, V, F> -where - F: FnMut(&K, &mut V) -> bool, -{ - fn drop(&mut self) { - self.for_each(drop); - } -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<K, V, F> fmt::Debug for DrainFilter<'_, K, V, F> -where - K: fmt::Debug, - V: fmt::Debug, - F: FnMut(&K, &mut V) -> bool, -{ - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("DrainFilter").field(&self.inner.peek()).finish() - } -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<K, V, F> Iterator for DrainFilter<'_, K, V, F> -where - F: FnMut(&K, &mut V) -> bool, -{ - type Item = (K, V); - - fn next(&mut self) -> Option<(K, V)> { - self.inner.next(&mut self.pred) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} - -impl<'a, K: 'a, V: 'a> DrainFilterInner<'a, K, V> { - /// Allow Debug implementations to predict the next element. - pub(super) fn peek(&self) -> Option<(&K, &V)> { - let edge = self.cur_leaf_edge.as_ref()?; - edge.reborrow().next_kv().ok().map(|kv| kv.into_kv()) - } - - /// Implementation of a typical `DrainFilter::next` method, given the predicate. - pub(super) fn next<F>(&mut self, pred: &mut F) -> Option<(K, V)> - where - F: FnMut(&K, &mut V) -> bool, - { - while let Ok(mut kv) = self.cur_leaf_edge.take()?.next_kv() { - let (k, v) = kv.kv_mut(); - if pred(k, v) { - *self.length -= 1; - let (k, v, leaf_edge_location) = kv.remove_kv_tracking(); - self.cur_leaf_edge = Some(leaf_edge_location); - return Some((k, v)); - } - self.cur_leaf_edge = Some(kv.next_leaf_edge()); - } - None - } - - /// Implementation of a typical `DrainFilter::size_hint` method. - pub(super) fn size_hint(&self) -> (usize, Option<usize>) { - (0, Some(*self.length)) - } -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<K, V, F> FusedIterator for DrainFilter<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<'a, K, V> Iterator for Range<'a, K, V> { - type Item = (&'a K, &'a V); - - fn next(&mut self) -> Option<(&'a K, &'a V)> { - if self.is_empty() { None } else { unsafe { Some(self.next_unchecked()) } } - } - - fn last(mut self) -> Option<(&'a K, &'a V)> { - self.next_back() - } - - fn min(mut self) -> Option<(&'a K, &'a V)> { - self.next() - } - - fn max(mut self) -> Option<(&'a K, &'a V)> { - self.next_back() - } -} - -#[stable(feature = "map_values_mut", since = "1.10.0")] -impl<'a, K, V> Iterator for ValuesMut<'a, K, V> { - type Item = &'a mut V; - - fn next(&mut self) -> Option<&'a mut V> { - self.inner.next().map(|(_, v)| v) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } - - fn last(mut self) -> Option<&'a mut V> { - self.next_back() - } -} - -#[stable(feature = "map_values_mut", since = "1.10.0")] -impl<'a, K, V> DoubleEndedIterator for ValuesMut<'a, K, V> { - fn next_back(&mut self) -> Option<&'a mut V> { - self.inner.next_back().map(|(_, v)| v) - } -} - -#[stable(feature = "map_values_mut", since = "1.10.0")] -impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> { - fn len(&self) -> usize { - self.inner.len() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for ValuesMut<'_, K, V> {} - -impl<'a, K, V> Range<'a, K, V> { - fn is_empty(&self) -> bool { - self.front == self.back - } - - unsafe fn next_unchecked(&mut self) -> (&'a K, &'a V) { - unsafe { unwrap_unchecked(self.front.as_mut()).next_unchecked() } - } -} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<'a, K, V> DoubleEndedIterator for Range<'a, K, V> { - fn next_back(&mut self) -> Option<(&'a K, &'a V)> { - if self.is_empty() { None } else { Some(unsafe { self.next_back_unchecked() }) } - } -} - -impl<'a, K, V> Range<'a, K, V> { - unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a V) { - unsafe { unwrap_unchecked(self.back.as_mut()).next_back_unchecked() } - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for Range<'_, K, V> {} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<K, V> Clone for Range<'_, K, V> { - fn clone(&self) -> Self { - Range { front: self.front, back: self.back } - } -} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<'a, K, V> Iterator for RangeMut<'a, K, V> { - type Item = (&'a K, &'a mut V); - - fn next(&mut self) -> Option<(&'a K, &'a mut V)> { - if self.is_empty() { - None - } else { - let (k, v) = unsafe { self.next_unchecked() }; - Some((k, v)) // coerce k from `&mut K` to `&K` - } - } - - fn last(mut self) -> Option<(&'a K, &'a mut V)> { - self.next_back() - } - - fn min(mut self) -> Option<(&'a K, &'a mut V)> { - self.next() - } - - fn max(mut self) -> Option<(&'a K, &'a mut V)> { - self.next_back() - } -} - -impl<'a, K, V> RangeMut<'a, K, V> { - fn is_empty(&self) -> bool { - self.front == self.back - } - - unsafe fn next_unchecked(&mut self) -> (&'a mut K, &'a mut V) { - unsafe { unwrap_unchecked(self.front.as_mut()).next_unchecked() } - } -} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<'a, K, V> DoubleEndedIterator for RangeMut<'a, K, V> { - fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> { - if self.is_empty() { - None - } else { - let (k, v) = unsafe { self.next_back_unchecked() }; - Some((k, v)) // coerce k from `&mut K` to `&K` - } - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for RangeMut<'_, K, V> {} - -impl<'a, K, V> RangeMut<'a, K, V> { - unsafe fn next_back_unchecked(&mut self) -> (&'a mut K, &'a mut V) { - unsafe { unwrap_unchecked(self.back.as_mut()).next_back_unchecked() } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Ord, V> FromIterator<(K, V)> for BTreeMap<K, V> { - fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> BTreeMap<K, V> { - let mut map = BTreeMap::new(); - map.extend(iter); - map - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Ord, V> Extend<(K, V)> for BTreeMap<K, V> { - #[inline] - fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T) { - iter.into_iter().for_each(move |(k, v)| { - self.insert(k, v); - }); - } - - #[inline] - fn extend_one(&mut self, (k, v): (K, V)) { - self.insert(k, v); - } -} - -#[stable(feature = "extend_ref", since = "1.2.0")] -impl<'a, K: Ord + Copy, V: Copy> Extend<(&'a K, &'a V)> for BTreeMap<K, V> { - fn extend<I: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iter: I) { - self.extend(iter.into_iter().map(|(&key, &value)| (key, value))); - } - - #[inline] - fn extend_one(&mut self, (&k, &v): (&'a K, &'a V)) { - self.insert(k, v); - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Hash, V: Hash> Hash for BTreeMap<K, V> { - fn hash<H: Hasher>(&self, state: &mut H) { - for elt in self { - elt.hash(state); - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Ord, V> Default for BTreeMap<K, V> { - /// Creates an empty `BTreeMap<K, V>`. - fn default() -> BTreeMap<K, V> { - BTreeMap::new() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: PartialEq, V: PartialEq> PartialEq for BTreeMap<K, V> { - fn eq(&self, other: &BTreeMap<K, V>) -> bool { - self.len() == other.len() && self.iter().zip(other).all(|(a, b)| a == b) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Eq, V: Eq> Eq for BTreeMap<K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: PartialOrd, V: PartialOrd> PartialOrd for BTreeMap<K, V> { - #[inline] - fn partial_cmp(&self, other: &BTreeMap<K, V>) -> Option<Ordering> { - self.iter().partial_cmp(other.iter()) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Ord, V: Ord> Ord for BTreeMap<K, V> { - #[inline] - fn cmp(&self, other: &BTreeMap<K, V>) -> Ordering { - self.iter().cmp(other.iter()) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Debug, V: Debug> Debug for BTreeMap<K, V> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_map().entries(self.iter()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K: Ord, Q: ?Sized, V> Index<&Q> for BTreeMap<K, V> -where - K: Borrow<Q>, - Q: Ord, -{ - type Output = V; - - /// Returns a reference to the value corresponding to the supplied key. - /// - /// # Panics - /// - /// Panics if the key is not present in the `BTreeMap`. - #[inline] - fn index(&self, key: &Q) -> &V { - self.get(key).expect("no entry found for key") - } -} - -/// Finds the leaf edges delimiting a specified range in or underneath a node. -fn range_search<BorrowType, K, V, Q: ?Sized, R: RangeBounds<Q>>( - root: NodeRef<BorrowType, K, V, marker::LeafOrInternal>, - range: R, -) -> ( - Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge>, - Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge>, -) -where - Q: Ord, - K: Borrow<Q>, -{ - match (range.start_bound(), range.end_bound()) { - (Excluded(s), Excluded(e)) if s == e => { - panic!("range start and end are equal and excluded in BTreeMap") - } - (Included(s) | Excluded(s), Included(e) | Excluded(e)) if s > e => { - panic!("range start is greater than range end in BTreeMap") - } - _ => {} - }; - - // We duplicate the root NodeRef here -- we will never access it in a way - // that overlaps references obtained from the root. - let mut min_node = unsafe { ptr::read(&root) }; - let mut max_node = root; - let mut min_found = false; - let mut max_found = false; - - loop { - let front = match (min_found, range.start_bound()) { - (false, Included(key)) => match search::search_node(min_node, key) { - Found(kv) => { - min_found = true; - kv.left_edge() - } - GoDown(edge) => edge, - }, - (false, Excluded(key)) => match search::search_node(min_node, key) { - Found(kv) => { - min_found = true; - kv.right_edge() - } - GoDown(edge) => edge, - }, - (true, Included(_)) => min_node.last_edge(), - (true, Excluded(_)) => min_node.first_edge(), - (_, Unbounded) => min_node.first_edge(), - }; - - let back = match (max_found, range.end_bound()) { - (false, Included(key)) => match search::search_node(max_node, key) { - Found(kv) => { - max_found = true; - kv.right_edge() - } - GoDown(edge) => edge, - }, - (false, Excluded(key)) => match search::search_node(max_node, key) { - Found(kv) => { - max_found = true; - kv.left_edge() - } - GoDown(edge) => edge, - }, - (true, Included(_)) => max_node.first_edge(), - (true, Excluded(_)) => max_node.last_edge(), - (_, Unbounded) => max_node.last_edge(), - }; - - if front.partial_cmp(&back) == Some(Ordering::Greater) { - panic!("Ord is ill-defined in BTreeMap range"); - } - match (front.force(), back.force()) { - (Leaf(f), Leaf(b)) => { - return (f, b); - } - (Internal(min_int), Internal(max_int)) => { - min_node = min_int.descend(); - max_node = max_int.descend(); - } - _ => unreachable!("BTreeMap has different depths"), - }; - } -} - -/// Equivalent to `range_search(k, v, ..)` without the `Ord` bound. -fn full_range_search<BorrowType, K, V>( - root: NodeRef<BorrowType, K, V, marker::LeafOrInternal>, -) -> ( - Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge>, - Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge>, -) { - // We duplicate the root NodeRef here -- we will never access it in a way - // that overlaps references obtained from the root. - let mut min_node = unsafe { ptr::read(&root) }; - let mut max_node = root; - loop { - let front = min_node.first_edge(); - let back = max_node.last_edge(); - match (front.force(), back.force()) { - (Leaf(f), Leaf(b)) => { - return (f, b); - } - (Internal(min_int), Internal(max_int)) => { - min_node = min_int.descend(); - max_node = max_int.descend(); - } - _ => unreachable!("BTreeMap has different depths"), - }; - } -} - -impl<K, V> BTreeMap<K, V> { - /// Gets an iterator over the entries of the map, sorted by key. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert(3, "c"); - /// map.insert(2, "b"); - /// map.insert(1, "a"); - /// - /// for (key, value) in map.iter() { - /// println!("{}: {}", key, value); - /// } - /// - /// let (first_key, first_value) = map.iter().next().unwrap(); - /// assert_eq!((*first_key, *first_value), (1, "a")); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn iter(&self) -> Iter<'_, K, V> { - if let Some(root) = &self.root { - let (f, b) = full_range_search(root.as_ref()); - - Iter { range: Range { front: Some(f), back: Some(b) }, length: self.length } - } else { - Iter { range: Range { front: None, back: None }, length: 0 } - } - } - - /// Gets a mutable iterator over the entries of the map, sorted by key. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map = BTreeMap::new(); - /// map.insert("a", 1); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// // add 10 to the value if the key isn't "a" - /// for (key, value) in map.iter_mut() { - /// if key != &"a" { - /// *value += 10; - /// } - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn iter_mut(&mut self) -> IterMut<'_, K, V> { - if let Some(root) = &mut self.root { - let (f, b) = full_range_search(root.as_mut()); - - IterMut { - range: RangeMut { front: Some(f), back: Some(b), _marker: PhantomData }, - length: self.length, - } - } else { - IterMut { range: RangeMut { front: None, back: None, _marker: PhantomData }, length: 0 } - } - } - - /// Gets an iterator over the keys of the map, in sorted order. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// a.insert(2, "b"); - /// a.insert(1, "a"); - /// - /// let keys: Vec<_> = a.keys().cloned().collect(); - /// assert_eq!(keys, [1, 2]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn keys(&self) -> Keys<'_, K, V> { - Keys { inner: self.iter() } - } - - /// Gets an iterator over the values of the map, in order by key. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, "hello"); - /// a.insert(2, "goodbye"); - /// - /// let values: Vec<&str> = a.values().cloned().collect(); - /// assert_eq!(values, ["hello", "goodbye"]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn values(&self) -> Values<'_, K, V> { - Values { inner: self.iter() } - } - - /// Gets a mutable iterator over the values of the map, in order by key. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// a.insert(1, String::from("hello")); - /// a.insert(2, String::from("goodbye")); - /// - /// for value in a.values_mut() { - /// value.push_str("!"); - /// } - /// - /// let values: Vec<String> = a.values().cloned().collect(); - /// assert_eq!(values, [String::from("hello!"), - /// String::from("goodbye!")]); - /// ``` - #[stable(feature = "map_values_mut", since = "1.10.0")] - pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> { - ValuesMut { inner: self.iter_mut() } - } - - /// Returns the number of elements in the map. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// assert_eq!(a.len(), 0); - /// a.insert(1, "a"); - /// assert_eq!(a.len(), 1); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn len(&self) -> usize { - self.length - } - - /// Returns `true` if the map contains no elements. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut a = BTreeMap::new(); - /// assert!(a.is_empty()); - /// a.insert(1, "a"); - /// assert!(!a.is_empty()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_empty(&self) -> bool { - self.len() == 0 - } - - /// If the root node is the empty (non-allocated) root node, allocate our - /// own node. Is an associated function to avoid borrowing the entire BTreeMap. - fn ensure_is_owned(root: &mut Option<node::Root<K, V>>) -> &mut node::Root<K, V> { - root.get_or_insert_with(node::Root::new_leaf) - } -} - -impl<'a, K: Ord, V> Entry<'a, K, V> { - /// Ensures a value is in the entry by inserting the default if empty, and returns - /// a mutable reference to the value in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// assert_eq!(map["poneyland"], 12); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn or_insert(self, default: V) -> &'a mut V { - match self { - Occupied(entry) => entry.into_mut(), - Vacant(entry) => entry.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. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, String> = BTreeMap::new(); - /// let s = "hoho".to_string(); - /// - /// map.entry("poneyland").or_insert_with(|| s); - /// - /// assert_eq!(map["poneyland"], "hoho".to_string()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V { - match self { - Occupied(entry) => entry.into_mut(), - Vacant(entry) => entry.insert(default()), - } - } - - #[unstable(feature = "or_insert_with_key", issue = "71024")] - /// Ensures a value is in the entry by inserting, if empty, the result of the default function, - /// which takes the key as its argument, and returns a mutable reference to the value in the - /// entry. - /// - /// # Examples - /// - /// ``` - /// #![feature(or_insert_with_key)] - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// - /// map.entry("poneyland").or_insert_with_key(|key| key.chars().count()); - /// - /// assert_eq!(map["poneyland"], 9); - /// ``` - #[inline] - pub fn or_insert_with_key<F: FnOnce(&K) -> V>(self, default: F) -> &'a mut V { - match self { - Occupied(entry) => entry.into_mut(), - Vacant(entry) => { - let value = default(entry.key()); - entry.insert(value) - } - } - } - - /// Returns a reference to this entry's key. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); - /// ``` - #[stable(feature = "map_entry_keys", since = "1.10.0")] - pub fn key(&self) -> &K { - match *self { - Occupied(ref entry) => entry.key(), - Vacant(ref entry) => entry.key(), - } - } - - /// Provides in-place mutable access to an occupied entry before any - /// potential inserts into the map. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// - /// map.entry("poneyland") - /// .and_modify(|e| { *e += 1 }) - /// .or_insert(42); - /// assert_eq!(map["poneyland"], 42); - /// - /// map.entry("poneyland") - /// .and_modify(|e| { *e += 1 }) - /// .or_insert(42); - /// assert_eq!(map["poneyland"], 43); - /// ``` - #[stable(feature = "entry_and_modify", since = "1.26.0")] - pub fn and_modify<F>(self, f: F) -> Self - where - F: FnOnce(&mut V), - { - match self { - Occupied(mut entry) => { - f(entry.get_mut()); - Occupied(entry) - } - Vacant(entry) => Vacant(entry), - } - } -} - -impl<'a, K: Ord, V: Default> Entry<'a, K, V> { - #[stable(feature = "entry_or_default", since = "1.28.0")] - /// Ensures a value is in the entry by inserting the default value if empty, - /// and returns a mutable reference to the value in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, Option<usize>> = BTreeMap::new(); - /// map.entry("poneyland").or_default(); - /// - /// assert_eq!(map["poneyland"], None); - /// ``` - pub fn or_default(self) -> &'a mut V { - match self { - Occupied(entry) => entry.into_mut(), - Vacant(entry) => entry.insert(Default::default()), - } - } -} - -impl<'a, K: Ord, V> VacantEntry<'a, K, V> { - /// Gets a reference to the key that would be used when inserting a value - /// through the VacantEntry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); - /// ``` - #[stable(feature = "map_entry_keys", since = "1.10.0")] - pub fn key(&self) -> &K { - &self.key - } - - /// Take ownership of the key. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// - /// if let Entry::Vacant(v) = map.entry("poneyland") { - /// v.into_key(); - /// } - /// ``` - #[stable(feature = "map_entry_recover_keys2", since = "1.12.0")] - pub fn into_key(self) -> K { - self.key - } - - /// Sets the value of the entry with the `VacantEntry`'s key, - /// and returns a mutable reference to it. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, u32> = BTreeMap::new(); - /// - /// if let Entry::Vacant(o) = map.entry("poneyland") { - /// o.insert(37); - /// } - /// assert_eq!(map["poneyland"], 37); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn insert(self, value: V) -> &'a mut V { - *self.length += 1; - - let out_ptr; - - let mut ins_k; - let mut ins_v; - let mut ins_edge; - - let mut cur_parent = match self.handle.insert(self.key, value) { - (Fit(handle), _) => return handle.into_kv_mut().1, - (Split(left, k, v, right), ptr) => { - ins_k = k; - ins_v = v; - ins_edge = right; - out_ptr = ptr; - left.ascend().map_err(|n| n.into_root_mut()) - } - }; - - loop { - match cur_parent { - Ok(parent) => match parent.insert(ins_k, ins_v, ins_edge) { - Fit(_) => return unsafe { &mut *out_ptr }, - Split(left, k, v, right) => { - ins_k = k; - ins_v = v; - ins_edge = right; - cur_parent = left.ascend().map_err(|n| n.into_root_mut()); - } - }, - Err(root) => { - root.push_level().push(ins_k, ins_v, ins_edge); - return unsafe { &mut *out_ptr }; - } - } - } - } -} - -impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> { - /// Gets a reference to the key in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); - /// ``` - #[stable(feature = "map_entry_keys", since = "1.10.0")] - pub fn key(&self) -> &K { - self.handle.reborrow().into_kv().0 - } - - /// Take ownership of the key and value from the map. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// // We delete the entry from the map. - /// o.remove_entry(); - /// } - /// - /// // If now try to get the value, it will panic: - /// // println!("{}", map["poneyland"]); - /// ``` - #[stable(feature = "map_entry_recover_keys2", since = "1.12.0")] - pub fn remove_entry(self) -> (K, V) { - self.remove_kv() - } - - /// Gets a reference to the value in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// assert_eq!(o.get(), &12); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn get(&self) -> &V { - self.handle.reborrow().into_kv().1 - } - - /// Gets a mutable reference to the value in the entry. - /// - /// If you need a reference to the `OccupiedEntry` that may outlive the - /// destruction of the `Entry` value, see [`into_mut`]. - /// - /// [`into_mut`]: #method.into_mut - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// assert_eq!(map["poneyland"], 12); - /// if let Entry::Occupied(mut o) = map.entry("poneyland") { - /// *o.get_mut() += 10; - /// assert_eq!(*o.get(), 22); - /// - /// // We can use the same Entry multiple times. - /// *o.get_mut() += 2; - /// } - /// assert_eq!(map["poneyland"], 24); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn get_mut(&mut self) -> &mut V { - self.handle.kv_mut().1 - } - - /// Converts the entry into a mutable reference to its value. - /// - /// If you need multiple references to the `OccupiedEntry`, see [`get_mut`]. - /// - /// [`get_mut`]: #method.get_mut - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// assert_eq!(map["poneyland"], 12); - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// *o.into_mut() += 10; - /// } - /// assert_eq!(map["poneyland"], 22); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn into_mut(self) -> &'a mut V { - self.handle.into_kv_mut().1 - } - - /// Sets the value of the entry with the `OccupiedEntry`'s key, - /// and returns the entry's old value. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(mut o) = map.entry("poneyland") { - /// assert_eq!(o.insert(15), 12); - /// } - /// assert_eq!(map["poneyland"], 15); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - 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. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeMap; - /// use std::collections::btree_map::Entry; - /// - /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// assert_eq!(o.remove(), 12); - /// } - /// // If we try to get "poneyland"'s value, it'll panic: - /// // println!("{}", map["poneyland"]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn remove(self) -> V { - self.remove_kv().1 - } - - fn remove_kv(self) -> (K, V) { - *self.length -= 1; - - let (old_key, old_val, _) = self.handle.remove_kv_tracking(); - (old_key, old_val) - } -} - -impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::KV> { - /// Removes a key/value-pair from the map, and returns that pair, as well as - /// the leaf edge corresponding to that former pair. - fn remove_kv_tracking( - self, - ) -> (K, V, Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>) { - let (mut pos, old_key, old_val, was_internal) = match self.force() { - Leaf(leaf) => { - let (hole, old_key, old_val) = leaf.remove(); - (hole, old_key, old_val, false) - } - Internal(mut internal) => { - // Replace the location freed in the internal node with the next KV, - // and remove that next KV from its leaf. - - let key_loc = internal.kv_mut().0 as *mut K; - let val_loc = internal.kv_mut().1 as *mut V; - - // Deleting from the left side is typically faster since we can - // just pop an element from the end of the KV array without - // needing to shift the other values. - let to_remove = internal.left_edge().descend().last_leaf_edge().left_kv().ok(); - let to_remove = unsafe { unwrap_unchecked(to_remove) }; - - let (hole, key, val) = to_remove.remove(); - - let old_key = unsafe { mem::replace(&mut *key_loc, key) }; - let old_val = unsafe { mem::replace(&mut *val_loc, val) }; - - (hole, old_key, old_val, true) - } - }; - - // Handle underflow - let mut cur_node = unsafe { ptr::read(&pos).into_node().forget_type() }; - let mut at_leaf = true; - while cur_node.len() < node::MIN_LEN { - match handle_underfull_node(cur_node) { - AtRoot => break, - Merged(edge, merged_with_left, offset) => { - // If we merged with our right sibling then our tracked - // position has not changed. However if we merged with our - // left sibling then our tracked position is now dangling. - if at_leaf && merged_with_left { - let idx = pos.idx() + offset; - let node = match unsafe { ptr::read(&edge).descend().force() } { - Leaf(leaf) => leaf, - Internal(_) => unreachable!(), - }; - pos = unsafe { Handle::new_edge(node, idx) }; - } - - let parent = edge.into_node(); - if parent.len() == 0 { - // We must be at the root - parent.into_root_mut().pop_level(); - break; - } else { - cur_node = parent.forget_type(); - at_leaf = false; - } - } - Stole(stole_from_left) => { - // Adjust the tracked position if we stole from a left sibling - if stole_from_left && at_leaf { - // SAFETY: This is safe since we just added an element to our node. - unsafe { - pos.next_unchecked(); - } - } - break; - } - } - } - - // If we deleted from an internal node then we need to compensate for - // the earlier swap and adjust the tracked position to point to the - // next element. - if was_internal { - pos = unsafe { unwrap_unchecked(pos.next_kv().ok()).next_leaf_edge() }; - } - - (old_key, old_val, pos) - } -} - -impl<K, V> node::Root<K, V> { - /// Removes empty levels on the top, but keep an empty leaf if the entire tree is empty. - fn fix_top(&mut self) { - while self.height() > 0 && self.as_ref().len() == 0 { - self.pop_level(); - } - } - - fn fix_right_border(&mut self) { - self.fix_top(); - - { - let mut cur_node = self.as_mut(); - - while let Internal(node) = cur_node.force() { - let mut last_kv = node.last_kv(); - - if last_kv.can_merge() { - cur_node = last_kv.merge().descend(); - } else { - let right_len = last_kv.reborrow().right_edge().descend().len(); - // `MINLEN + 1` to avoid readjust if merge happens on the next level. - if right_len < node::MIN_LEN + 1 { - last_kv.bulk_steal_left(node::MIN_LEN + 1 - right_len); - } - cur_node = last_kv.right_edge().descend(); - } - } - } - - self.fix_top(); - } - - /// The symmetric clone of `fix_right_border`. - fn fix_left_border(&mut self) { - self.fix_top(); - - { - let mut cur_node = self.as_mut(); - - while let Internal(node) = cur_node.force() { - let mut first_kv = node.first_kv(); - - if first_kv.can_merge() { - cur_node = first_kv.merge().descend(); - } else { - let left_len = first_kv.reborrow().left_edge().descend().len(); - if left_len < node::MIN_LEN + 1 { - first_kv.bulk_steal_right(node::MIN_LEN + 1 - left_len); - } - cur_node = first_kv.left_edge().descend(); - } - } - } - - self.fix_top(); - } -} - -enum UnderflowResult<'a, K, V> { - AtRoot, - Merged(Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::Edge>, bool, usize), - Stole(bool), -} - -fn handle_underfull_node<K, V>( - node: NodeRef<marker::Mut<'_>, K, V, marker::LeafOrInternal>, -) -> UnderflowResult<'_, K, V> { - let parent = match node.ascend() { - Ok(parent) => parent, - Err(_) => return AtRoot, - }; - - let (is_left, mut handle) = match parent.left_kv() { - Ok(left) => (true, left), - Err(parent) => { - let right = unsafe { unwrap_unchecked(parent.right_kv().ok()) }; - (false, right) - } - }; - - if handle.can_merge() { - let offset = if is_left { handle.reborrow().left_edge().descend().len() + 1 } else { 0 }; - Merged(handle.merge(), is_left, offset) - } else { - if is_left { - handle.steal_left(); - } else { - handle.steal_right(); - } - Stole(is_left) - } -} - -impl<K: Ord, V, I: Iterator<Item = (K, V)>> Iterator for MergeIter<K, V, I> { - type Item = (K, V); - - fn next(&mut self) -> Option<(K, V)> { - let res = match (self.left.peek(), self.right.peek()) { - (Some(&(ref left_key, _)), Some(&(ref right_key, _))) => left_key.cmp(right_key), - (Some(_), None) => Ordering::Less, - (None, Some(_)) => Ordering::Greater, - (None, None) => return None, - }; - - // Check which elements comes first and only advance the corresponding iterator. - // If two keys are equal, take the value from `right`. - match res { - Ordering::Less => self.left.next(), - Ordering::Greater => self.right.next(), - Ordering::Equal => { - self.left.next(); - self.right.next() - } - } - } -} diff --git a/src/liballoc/collections/btree/mod.rs b/src/liballoc/collections/btree/mod.rs deleted file mode 100644 index 543ff41a4d4..00000000000 --- a/src/liballoc/collections/btree/mod.rs +++ /dev/null @@ -1,27 +0,0 @@ -pub mod map; -mod navigate; -mod node; -mod search; -pub mod set; - -#[doc(hidden)] -trait Recover<Q: ?Sized> { - type Key; - - fn get(&self, key: &Q) -> Option<&Self::Key>; - fn take(&mut self, key: &Q) -> Option<Self::Key>; - fn replace(&mut self, key: Self::Key) -> Option<Self::Key>; -} - -#[inline(always)] -pub unsafe fn unwrap_unchecked<T>(val: Option<T>) -> T { - val.unwrap_or_else(|| { - if cfg!(debug_assertions) { - panic!("'unchecked' unwrap on None in BTreeMap"); - } else { - unsafe { - core::intrinsics::unreachable(); - } - } - }) -} diff --git a/src/liballoc/collections/btree/navigate.rs b/src/liballoc/collections/btree/navigate.rs deleted file mode 100644 index 44f0e25bbd7..00000000000 --- a/src/liballoc/collections/btree/navigate.rs +++ /dev/null @@ -1,261 +0,0 @@ -use core::ptr; - -use super::node::{marker, ForceResult::*, Handle, NodeRef}; -use super::unwrap_unchecked; - -impl<BorrowType, K, V> Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge> { - /// Given a leaf edge handle, returns [`Result::Ok`] with a handle to the neighboring KV - /// on the right side, which is either in the same leaf node or in an ancestor node. - /// If the leaf edge is the last one in the tree, returns [`Result::Err`] with the root node. - pub fn next_kv( - self, - ) -> Result< - Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, marker::KV>, - NodeRef<BorrowType, K, V, marker::LeafOrInternal>, - > { - let mut edge = self.forget_node_type(); - loop { - edge = match edge.right_kv() { - Ok(internal_kv) => return Ok(internal_kv), - Err(last_edge) => match last_edge.into_node().ascend() { - Ok(parent_edge) => parent_edge.forget_node_type(), - Err(root) => return Err(root.forget_type()), - }, - } - } - } - - /// Given a leaf edge handle, returns [`Result::Ok`] with a handle to the neighboring KV - /// on the left side, which is either in the same leaf node or in an ancestor node. - /// If the leaf edge is the first one in the tree, returns [`Result::Err`] with the root node. - pub fn next_back_kv( - self, - ) -> Result< - Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, marker::KV>, - NodeRef<BorrowType, K, V, marker::LeafOrInternal>, - > { - let mut edge = self.forget_node_type(); - loop { - edge = match edge.left_kv() { - Ok(internal_kv) => return Ok(internal_kv), - Err(last_edge) => match last_edge.into_node().ascend() { - Ok(parent_edge) => parent_edge.forget_node_type(), - Err(root) => return Err(root.forget_type()), - }, - } - } - } -} - -macro_rules! def_next_kv_uncheched_dealloc { - { unsafe fn $name:ident : $adjacent_kv:ident } => { - /// Given a leaf edge handle into an owned tree, returns a handle to the next KV, - /// while deallocating any node left behind. - /// Unsafe for two reasons: - /// - The caller must ensure that the leaf edge is not the last one in the tree. - /// - The node pointed at by the given handle, and its ancestors, may be deallocated, - /// while the reference to those nodes in the surviving ancestors is left dangling; - /// thus using the returned handle to navigate further is dangerous. - unsafe fn $name <K, V>( - leaf_edge: Handle<NodeRef<marker::Owned, K, V, marker::Leaf>, marker::Edge>, - ) -> Handle<NodeRef<marker::Owned, K, V, marker::LeafOrInternal>, marker::KV> { - let mut edge = leaf_edge.forget_node_type(); - loop { - edge = match edge.$adjacent_kv() { - Ok(internal_kv) => return internal_kv, - Err(last_edge) => { - unsafe { - let parent_edge = last_edge.into_node().deallocate_and_ascend(); - unwrap_unchecked(parent_edge).forget_node_type() - } - } - } - } - } - }; -} - -def_next_kv_uncheched_dealloc! {unsafe fn next_kv_unchecked_dealloc: right_kv} -def_next_kv_uncheched_dealloc! {unsafe fn next_back_kv_unchecked_dealloc: left_kv} - -/// This replaces the value behind the `v` unique reference by calling the -/// relevant function. -/// -/// Safety: The change closure must not panic. -#[inline] -unsafe fn replace<T, R>(v: &mut T, change: impl FnOnce(T) -> (T, R)) -> R { - let value = unsafe { ptr::read(v) }; - let (new_value, ret) = change(value); - unsafe { - ptr::write(v, new_value); - } - ret -} - -impl<'a, K, V> Handle<NodeRef<marker::Immut<'a>, K, V, marker::Leaf>, marker::Edge> { - /// Moves the leaf edge handle to the next leaf edge and returns references to the - /// key and value in between. - /// Unsafe because the caller must ensure that the leaf edge is not the last one in the tree. - pub unsafe fn next_unchecked(&mut self) -> (&'a K, &'a V) { - unsafe { - replace(self, |leaf_edge| { - let kv = leaf_edge.next_kv(); - let kv = unwrap_unchecked(kv.ok()); - (kv.next_leaf_edge(), kv.into_kv()) - }) - } - } - - /// Moves the leaf edge handle to the previous leaf edge and returns references to the - /// key and value in between. - /// Unsafe because the caller must ensure that the leaf edge is not the first one in the tree. - pub unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a V) { - unsafe { - replace(self, |leaf_edge| { - let kv = leaf_edge.next_back_kv(); - let kv = unwrap_unchecked(kv.ok()); - (kv.next_back_leaf_edge(), kv.into_kv()) - }) - } - } -} - -impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge> { - /// Moves the leaf edge handle to the next leaf edge and returns references to the - /// key and value in between. - /// Unsafe for two reasons: - /// - The caller must ensure that the leaf edge is not the last one in the tree. - /// - Using the updated handle may well invalidate the returned references. - pub unsafe fn next_unchecked(&mut self) -> (&'a mut K, &'a mut V) { - unsafe { - let kv = replace(self, |leaf_edge| { - let kv = leaf_edge.next_kv(); - let kv = unwrap_unchecked(kv.ok()); - (ptr::read(&kv).next_leaf_edge(), kv) - }); - // Doing the descend (and perhaps another move) invalidates the references - // returned by `into_kv_mut`, so we have to do this last. - kv.into_kv_mut() - } - } - - /// Moves the leaf edge handle to the previous leaf and returns references to the - /// key and value in between. - /// Unsafe for two reasons: - /// - The caller must ensure that the leaf edge is not the first one in the tree. - /// - Using the updated handle may well invalidate the returned references. - pub unsafe fn next_back_unchecked(&mut self) -> (&'a mut K, &'a mut V) { - unsafe { - let kv = replace(self, |leaf_edge| { - let kv = leaf_edge.next_back_kv(); - let kv = unwrap_unchecked(kv.ok()); - (ptr::read(&kv).next_back_leaf_edge(), kv) - }); - // Doing the descend (and perhaps another move) invalidates the references - // returned by `into_kv_mut`, so we have to do this last. - kv.into_kv_mut() - } - } -} - -impl<K, V> Handle<NodeRef<marker::Owned, K, V, marker::Leaf>, marker::Edge> { - /// Moves the leaf edge handle to the next leaf edge and returns the key and value - /// in between, while deallocating any node left behind. - /// Unsafe for two reasons: - /// - The caller must ensure that the leaf edge is not the last one in the tree - /// and is not a handle previously resulting from counterpart `next_back_unchecked`. - /// - Further use of the updated leaf edge handle is very dangerous. In particular, - /// if the leaf edge is the last edge of a node, that node and possibly ancestors - /// will be deallocated, while the reference to those nodes in the surviving ancestor - /// is left dangling. - /// The only safe way to proceed with the updated handle is to compare it, drop it, - /// call this method again subject to both preconditions listed in the first point, - /// or call counterpart `next_back_unchecked` subject to its preconditions. - pub unsafe fn next_unchecked(&mut self) -> (K, V) { - unsafe { - replace(self, |leaf_edge| { - let kv = next_kv_unchecked_dealloc(leaf_edge); - let k = ptr::read(kv.reborrow().into_kv().0); - let v = ptr::read(kv.reborrow().into_kv().1); - (kv.next_leaf_edge(), (k, v)) - }) - } - } - - /// Moves the leaf edge handle to the previous leaf edge and returns the key - /// and value in between, while deallocating any node left behind. - /// Unsafe for two reasons: - /// - The caller must ensure that the leaf edge is not the first one in the tree - /// and is not a handle previously resulting from counterpart `next_unchecked`. - /// - Further use of the updated leaf edge handle is very dangerous. In particular, - /// if the leaf edge is the first edge of a node, that node and possibly ancestors - /// will be deallocated, while the reference to those nodes in the surviving ancestor - /// is left dangling. - /// The only safe way to proceed with the updated handle is to compare it, drop it, - /// call this method again subject to both preconditions listed in the first point, - /// or call counterpart `next_unchecked` subject to its preconditions. - pub unsafe fn next_back_unchecked(&mut self) -> (K, V) { - unsafe { - replace(self, |leaf_edge| { - let kv = next_back_kv_unchecked_dealloc(leaf_edge); - let k = ptr::read(kv.reborrow().into_kv().0); - let v = ptr::read(kv.reborrow().into_kv().1); - (kv.next_back_leaf_edge(), (k, v)) - }) - } - } -} - -impl<BorrowType, K, V> NodeRef<BorrowType, K, V, marker::LeafOrInternal> { - /// Returns the leftmost leaf edge in or underneath a node - in other words, the edge - /// you need first when navigating forward (or last when navigating backward). - #[inline] - pub fn first_leaf_edge(self) -> Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge> { - let mut node = self; - loop { - match node.force() { - Leaf(leaf) => return leaf.first_edge(), - Internal(internal) => node = internal.first_edge().descend(), - } - } - } - - /// Returns the rightmost leaf edge in or underneath a node - in other words, the edge - /// you need last when navigating forward (or first when navigating backward). - #[inline] - pub fn last_leaf_edge(self) -> Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge> { - let mut node = self; - loop { - match node.force() { - Leaf(leaf) => return leaf.last_edge(), - Internal(internal) => node = internal.last_edge().descend(), - } - } - } -} - -impl<BorrowType, K, V> Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, marker::KV> { - /// Returns the leaf edge closest to a KV for forward navigation. - pub fn next_leaf_edge(self) -> Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge> { - match self.force() { - Leaf(leaf_kv) => leaf_kv.right_edge(), - Internal(internal_kv) => { - let next_internal_edge = internal_kv.right_edge(); - next_internal_edge.descend().first_leaf_edge() - } - } - } - - /// Returns the leaf edge closest to a KV for backward navigation. - pub fn next_back_leaf_edge( - self, - ) -> Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge> { - match self.force() { - Leaf(leaf_kv) => leaf_kv.left_edge(), - Internal(internal_kv) => { - let next_internal_edge = internal_kv.left_edge(); - next_internal_edge.descend().last_leaf_edge() - } - } - } -} diff --git a/src/liballoc/collections/btree/node.rs b/src/liballoc/collections/btree/node.rs deleted file mode 100644 index f7bd64608d6..00000000000 --- a/src/liballoc/collections/btree/node.rs +++ /dev/null @@ -1,1488 +0,0 @@ -// This is an attempt at an implementation following the ideal -// -// ``` -// struct BTreeMap<K, V> { -// height: usize, -// root: Option<Box<Node<K, V, height>>> -// } -// -// struct Node<K, V, height: usize> { -// keys: [K; 2 * B - 1], -// vals: [V; 2 * B - 1], -// edges: if height > 0 { -// [Box<Node<K, V, height - 1>>; 2 * B] -// } else { () }, -// parent: *const Node<K, V, height + 1>, -// parent_idx: u16, -// len: u16, -// } -// ``` -// -// Since Rust doesn't actually have dependent types and polymorphic recursion, -// we make do with lots of unsafety. - -// A major goal of this module is to avoid complexity by treating the tree as a generic (if -// weirdly shaped) container and avoiding dealing with most of the B-Tree invariants. As such, -// this module doesn't care whether the entries are sorted, which nodes can be underfull, or -// even what underfull means. However, we do rely on a few invariants: -// -// - Trees must have uniform depth/height. This means that every path down to a leaf from a -// given node has exactly the same length. -// - A node of length `n` has `n` keys, `n` values, and (in an internal node) `n + 1` edges. -// This implies that even an empty internal node has at least one edge. - -use core::cmp::Ordering; -use core::marker::PhantomData; -use core::mem::{self, MaybeUninit}; -use core::ptr::{self, NonNull, Unique}; -use core::slice; - -use crate::alloc::{AllocRef, Global, Layout}; -use crate::boxed::Box; - -const B: usize = 6; -pub const MIN_LEN: usize = B - 1; -pub const CAPACITY: usize = 2 * B - 1; - -/// The underlying representation of leaf nodes. -#[repr(C)] -struct LeafNode<K, V> { - /// We use `*const` as opposed to `*mut` so as to be covariant in `K` and `V`. - /// This either points to an actual node or is null. - parent: *const InternalNode<K, V>, - - /// This node's index into the parent node's `edges` array. - /// `*node.parent.edges[node.parent_idx]` should be the same thing as `node`. - /// This is only guaranteed to be initialized when `parent` is non-null. - parent_idx: MaybeUninit<u16>, - - /// The number of keys and values this node stores. - /// - /// This next to `parent_idx` to encourage the compiler to join `len` and - /// `parent_idx` into the same 32-bit word, reducing space overhead. - len: u16, - - /// The arrays storing the actual data of the node. Only the first `len` elements of each - /// array are initialized and valid. - keys: [MaybeUninit<K>; CAPACITY], - vals: [MaybeUninit<V>; CAPACITY], -} - -impl<K, V> LeafNode<K, V> { - /// Creates a new `LeafNode`. Unsafe because all nodes should really be hidden behind - /// `BoxedNode`, preventing accidental dropping of uninitialized keys and values. - unsafe fn new() -> Self { - LeafNode { - // As a general policy, we leave fields uninitialized if they can be, as this should - // be both slightly faster and easier to track in Valgrind. - keys: [MaybeUninit::UNINIT; CAPACITY], - vals: [MaybeUninit::UNINIT; CAPACITY], - parent: ptr::null(), - parent_idx: MaybeUninit::uninit(), - len: 0, - } - } -} - -/// The underlying representation of internal nodes. As with `LeafNode`s, these should be hidden -/// behind `BoxedNode`s to prevent dropping uninitialized keys and values. Any pointer to an -/// `InternalNode` can be directly casted to a pointer to the underlying `LeafNode` portion of the -/// node, allowing code to act on leaf and internal nodes generically without having to even check -/// which of the two a pointer is pointing at. This property is enabled by the use of `repr(C)`. -#[repr(C)] -struct InternalNode<K, V> { - data: LeafNode<K, V>, - - /// The pointers to the children of this node. `len + 1` of these are considered - /// initialized and valid. Although during the process of `into_iter` or `drop`, - /// some pointers are dangling while others still need to be traversed. - edges: [MaybeUninit<BoxedNode<K, V>>; 2 * B], -} - -impl<K, V> InternalNode<K, V> { - /// Creates a new `InternalNode`. - /// - /// This is unsafe for two reasons. First, it returns an `InternalNode` by value, risking - /// dropping of uninitialized fields. Second, an invariant of internal nodes is that `len + 1` - /// edges are initialized and valid, meaning that even when the node is empty (having a - /// `len` of 0), there must be one initialized and valid edge. This function does not set up - /// such an edge. - unsafe fn new() -> Self { - InternalNode { data: unsafe { LeafNode::new() }, edges: [MaybeUninit::UNINIT; 2 * B] } - } -} - -/// A managed, non-null pointer to a node. This is either an owned pointer to -/// `LeafNode<K, V>` or an owned pointer to `InternalNode<K, V>`. -/// -/// However, `BoxedNode` contains no information as to which of the two types -/// of nodes it actually contains, and, partially due to this lack of information, -/// has no destructor. -struct BoxedNode<K, V> { - ptr: Unique<LeafNode<K, V>>, -} - -impl<K, V> BoxedNode<K, V> { - fn from_leaf(node: Box<LeafNode<K, V>>) -> Self { - BoxedNode { ptr: Box::into_unique(node) } - } - - fn from_internal(node: Box<InternalNode<K, V>>) -> Self { - BoxedNode { ptr: Box::into_unique(node).cast() } - } - - unsafe fn from_ptr(ptr: NonNull<LeafNode<K, V>>) -> Self { - BoxedNode { ptr: unsafe { Unique::new_unchecked(ptr.as_ptr()) } } - } - - fn as_ptr(&self) -> NonNull<LeafNode<K, V>> { - NonNull::from(self.ptr) - } -} - -/// An owned tree. -/// -/// Note that this does not have a destructor, and must be cleaned up manually. -pub struct Root<K, V> { - node: BoxedNode<K, V>, - /// The number of levels below the root node. - height: usize, -} - -unsafe impl<K: Sync, V: Sync> Sync for Root<K, V> {} -unsafe impl<K: Send, V: Send> Send for Root<K, V> {} - -impl<K, V> Root<K, V> { - /// Returns the number of levels below the root. - pub fn height(&self) -> usize { - self.height - } - - /// Returns a new owned tree, with its own root node that is initially empty. - pub fn new_leaf() -> Self { - Root { node: BoxedNode::from_leaf(Box::new(unsafe { LeafNode::new() })), height: 0 } - } - - pub fn as_ref(&self) -> NodeRef<marker::Immut<'_>, K, V, marker::LeafOrInternal> { - NodeRef { - height: self.height, - node: self.node.as_ptr(), - root: ptr::null(), - _marker: PhantomData, - } - } - - pub fn as_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::LeafOrInternal> { - NodeRef { - height: self.height, - node: self.node.as_ptr(), - root: self as *mut _, - _marker: PhantomData, - } - } - - pub fn into_ref(self) -> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> { - NodeRef { - height: self.height, - node: self.node.as_ptr(), - root: ptr::null(), - _marker: PhantomData, - } - } - - /// Adds a new internal node with a single edge, pointing to the previous root, and make that - /// new node the root. This increases the height by 1 and is the opposite of `pop_level`. - pub fn push_level(&mut self) -> NodeRef<marker::Mut<'_>, K, V, marker::Internal> { - let mut new_node = Box::new(unsafe { InternalNode::new() }); - new_node.edges[0].write(unsafe { BoxedNode::from_ptr(self.node.as_ptr()) }); - - self.node = BoxedNode::from_internal(new_node); - self.height += 1; - - let mut ret = NodeRef { - height: self.height, - node: self.node.as_ptr(), - root: self as *mut _, - _marker: PhantomData, - }; - - unsafe { - ret.reborrow_mut().first_edge().correct_parent_link(); - } - - ret - } - - /// Removes the root node, using its first child as the new root. This cannot be called when - /// the tree consists only of a leaf node. As it is intended only to be called when the root - /// has only one edge, no cleanup is done on any of the other children of the root. - /// This decreases the height by 1 and is the opposite of `push_level`. - pub fn pop_level(&mut self) { - assert!(self.height > 0); - - let top = self.node.ptr; - - self.node = unsafe { - BoxedNode::from_ptr( - self.as_mut().cast_unchecked::<marker::Internal>().first_edge().descend().node, - ) - }; - self.height -= 1; - unsafe { - (*self.as_mut().as_leaf_mut()).parent = ptr::null(); - } - - unsafe { - Global.dealloc(NonNull::from(top).cast(), Layout::new::<InternalNode<K, V>>()); - } - } -} - -// N.B. `NodeRef` is always covariant in `K` and `V`, even when the `BorrowType` -// is `Mut`. This is technically wrong, but cannot result in any unsafety due to -// internal use of `NodeRef` because we stay completely generic over `K` and `V`. -// However, whenever a public type wraps `NodeRef`, make sure that it has the -// correct variance. -/// A reference to a node. -/// -/// This type has a number of parameters that controls how it acts: -/// - `BorrowType`: This can be `Immut<'a>` or `Mut<'a>` for some `'a` or `Owned`. -/// When this is `Immut<'a>`, the `NodeRef` acts roughly like `&'a Node`, -/// when this is `Mut<'a>`, the `NodeRef` acts roughly like `&'a mut Node`, -/// and when this is `Owned`, the `NodeRef` acts roughly like `Box<Node>`. -/// - `K` and `V`: These control what types of things are stored in the nodes. -/// - `Type`: This can be `Leaf`, `Internal`, or `LeafOrInternal`. When this is -/// `Leaf`, the `NodeRef` points to a leaf node, when this is `Internal` the -/// `NodeRef` points to an internal node, and when this is `LeafOrInternal` the -/// `NodeRef` could be pointing to either type of node. -pub struct NodeRef<BorrowType, K, V, Type> { - /// The number of levels below the node. - height: usize, - node: NonNull<LeafNode<K, V>>, - // `root` is null unless the borrow type is `Mut` - root: *const Root<K, V>, - _marker: PhantomData<(BorrowType, Type)>, -} - -impl<'a, K: 'a, V: 'a, Type> Copy for NodeRef<marker::Immut<'a>, K, V, Type> {} -impl<'a, K: 'a, V: 'a, Type> Clone for NodeRef<marker::Immut<'a>, K, V, Type> { - fn clone(&self) -> Self { - *self - } -} - -unsafe impl<BorrowType, K: Sync, V: Sync, Type> Sync for NodeRef<BorrowType, K, V, Type> {} - -unsafe impl<'a, K: Sync + 'a, V: Sync + 'a, Type> Send for NodeRef<marker::Immut<'a>, K, V, Type> {} -unsafe impl<'a, K: Send + 'a, V: Send + 'a, Type> Send for NodeRef<marker::Mut<'a>, K, V, Type> {} -unsafe impl<K: Send, V: Send, Type> Send for NodeRef<marker::Owned, K, V, Type> {} - -impl<BorrowType, K, V> NodeRef<BorrowType, K, V, marker::Internal> { - fn as_internal(&self) -> &InternalNode<K, V> { - unsafe { &*(self.node.as_ptr() as *mut InternalNode<K, V>) } - } -} - -impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> { - fn as_internal_mut(&mut self) -> &mut InternalNode<K, V> { - unsafe { &mut *(self.node.as_ptr() as *mut InternalNode<K, V>) } - } -} - -impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> { - /// Finds the length of the node. This is the number of keys or values. In an - /// internal node, the number of edges is `len() + 1`. - /// For any node, the number of possible edge handles is also `len() + 1`. - /// Note that, despite being safe, calling this function can have the side effect - /// of invalidating mutable references that unsafe code has created. - pub fn len(&self) -> usize { - self.as_leaf().len as usize - } - - /// Returns the height of this node in the whole tree. Zero height denotes the - /// leaf level. - pub fn height(&self) -> usize { - self.height - } - - /// Removes any static information about whether this node is a `Leaf` or an - /// `Internal` node. - pub fn forget_type(self) -> NodeRef<BorrowType, K, V, marker::LeafOrInternal> { - NodeRef { height: self.height, node: self.node, root: self.root, _marker: PhantomData } - } - - /// Temporarily takes out another, immutable reference to the same node. - fn reborrow(&self) -> NodeRef<marker::Immut<'_>, K, V, Type> { - NodeRef { height: self.height, node: self.node, root: self.root, _marker: PhantomData } - } - - /// Exposes the leaf "portion" of any leaf or internal node. - /// If the node is a leaf, this function simply opens up its data. - /// If the node is an internal node, so not a leaf, it does have all the data a leaf has - /// (header, keys and values), and this function exposes that. - fn as_leaf(&self) -> &LeafNode<K, V> { - // The node must be valid for at least the LeafNode portion. - // This is not a reference in the NodeRef type because we don't know if - // it should be unique or shared. - unsafe { self.node.as_ref() } - } - - /// Borrows a view into the keys stored in the node. - pub fn keys(&self) -> &[K] { - self.reborrow().into_key_slice() - } - - /// Borrows a view into the values stored in the node. - fn vals(&self) -> &[V] { - self.reborrow().into_val_slice() - } - - /// Finds the parent of the current node. Returns `Ok(handle)` if the current - /// node actually has a parent, where `handle` points to the edge of the parent - /// that points to the current node. Returns `Err(self)` if the current node has - /// no parent, giving back the original `NodeRef`. - /// - /// `edge.descend().ascend().unwrap()` and `node.ascend().unwrap().descend()` should - /// both, upon success, do nothing. - pub fn ascend( - self, - ) -> Result<Handle<NodeRef<BorrowType, K, V, marker::Internal>, marker::Edge>, Self> { - let parent_as_leaf = self.as_leaf().parent as *const LeafNode<K, V>; - if let Some(non_zero) = NonNull::new(parent_as_leaf as *mut _) { - Ok(Handle { - node: NodeRef { - height: self.height + 1, - node: non_zero, - root: self.root, - _marker: PhantomData, - }, - idx: unsafe { usize::from(*self.as_leaf().parent_idx.as_ptr()) }, - _marker: PhantomData, - }) - } else { - Err(self) - } - } - - pub fn first_edge(self) -> Handle<Self, marker::Edge> { - unsafe { Handle::new_edge(self, 0) } - } - - pub fn last_edge(self) -> Handle<Self, marker::Edge> { - let len = self.len(); - unsafe { Handle::new_edge(self, len) } - } - - /// Note that `self` must be nonempty. - pub fn first_kv(self) -> Handle<Self, marker::KV> { - let len = self.len(); - assert!(len > 0); - unsafe { Handle::new_kv(self, 0) } - } - - /// Note that `self` must be nonempty. - pub fn last_kv(self) -> Handle<Self, marker::KV> { - let len = self.len(); - assert!(len > 0); - unsafe { Handle::new_kv(self, len - 1) } - } -} - -impl<K, V> NodeRef<marker::Owned, K, V, marker::LeafOrInternal> { - /// Similar to `ascend`, gets a reference to a node's parent node, but also - /// deallocate the current node in the process. This is unsafe because the - /// current node will still be accessible despite being deallocated. - pub unsafe fn deallocate_and_ascend( - self, - ) -> Option<Handle<NodeRef<marker::Owned, K, V, marker::Internal>, marker::Edge>> { - let height = self.height; - let node = self.node; - let ret = self.ascend().ok(); - unsafe { - Global.dealloc( - node.cast(), - if height > 0 { - Layout::new::<InternalNode<K, V>>() - } else { - Layout::new::<LeafNode<K, V>>() - }, - ); - } - ret - } -} - -impl<'a, K, V, Type> NodeRef<marker::Mut<'a>, K, V, Type> { - /// Unsafely asserts to the compiler some static information about whether this - /// node is a `Leaf` or an `Internal`. - unsafe fn cast_unchecked<NewType>(&mut self) -> NodeRef<marker::Mut<'_>, K, V, NewType> { - NodeRef { height: self.height, node: self.node, root: self.root, _marker: PhantomData } - } - - /// Temporarily takes out another, mutable reference to the same node. Beware, as - /// this method is very dangerous, doubly so since it may not immediately appear - /// dangerous. - /// - /// Because mutable pointers can roam anywhere around the tree and can even (through - /// `into_root_mut`) mess with the root of the tree, the result of `reborrow_mut` - /// can easily be used to make the original mutable pointer dangling, or, in the case - /// of a reborrowed handle, out of bounds. - // FIXME(@gereeter) consider adding yet another type parameter to `NodeRef` that restricts - // the use of `ascend` and `into_root_mut` on reborrowed pointers, preventing this unsafety. - unsafe fn reborrow_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, Type> { - NodeRef { height: self.height, node: self.node, root: self.root, _marker: PhantomData } - } - - /// Exposes the leaf "portion" of any leaf or internal node for writing. - /// If the node is a leaf, this function simply opens up its data. - /// If the node is an internal node, so not a leaf, it does have all the data a leaf has - /// (header, keys and values), and this function exposes that. - /// - /// Returns a raw ptr to avoid asserting exclusive access to the entire node. - fn as_leaf_mut(&mut self) -> *mut LeafNode<K, V> { - self.node.as_ptr() - } - - fn keys_mut(&mut self) -> &mut [K] { - // SAFETY: the caller will not be able to call further methods on self - // until the key slice reference is dropped, as we have unique access - // for the lifetime of the borrow. - unsafe { self.reborrow_mut().into_key_slice_mut() } - } - - fn vals_mut(&mut self) -> &mut [V] { - // SAFETY: the caller will not be able to call further methods on self - // until the value slice reference is dropped, as we have unique access - // for the lifetime of the borrow. - unsafe { self.reborrow_mut().into_val_slice_mut() } - } -} - -impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Immut<'a>, K, V, Type> { - fn into_key_slice(self) -> &'a [K] { - unsafe { slice::from_raw_parts(MaybeUninit::first_ptr(&self.as_leaf().keys), self.len()) } - } - - fn into_val_slice(self) -> &'a [V] { - unsafe { slice::from_raw_parts(MaybeUninit::first_ptr(&self.as_leaf().vals), self.len()) } - } - - fn into_slices(self) -> (&'a [K], &'a [V]) { - // SAFETY: equivalent to reborrow() except not requiring Type: 'a - let k = unsafe { ptr::read(&self) }; - (k.into_key_slice(), self.into_val_slice()) - } -} - -impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> { - /// Gets a mutable reference to the root itself. This is useful primarily when the - /// height of the tree needs to be adjusted. Never call this on a reborrowed pointer. - pub fn into_root_mut(self) -> &'a mut Root<K, V> { - unsafe { &mut *(self.root as *mut Root<K, V>) } - } - - fn into_key_slice_mut(mut self) -> &'a mut [K] { - // SAFETY: The keys of a node must always be initialized up to length. - unsafe { - slice::from_raw_parts_mut( - MaybeUninit::first_ptr_mut(&mut (*self.as_leaf_mut()).keys), - self.len(), - ) - } - } - - fn into_val_slice_mut(mut self) -> &'a mut [V] { - // SAFETY: The values of a node must always be initialized up to length. - unsafe { - slice::from_raw_parts_mut( - MaybeUninit::first_ptr_mut(&mut (*self.as_leaf_mut()).vals), - self.len(), - ) - } - } - - fn into_slices_mut(mut self) -> (&'a mut [K], &'a mut [V]) { - // We cannot use the getters here, because calling the second one - // invalidates the reference returned by the first. - // More precisely, it is the call to `len` that is the culprit, - // because that creates a shared reference to the header, which *can* - // overlap with the keys (and even the values, for ZST keys). - let len = self.len(); - let leaf = self.as_leaf_mut(); - // SAFETY: The keys and values of a node must always be initialized up to length. - let keys = unsafe { - slice::from_raw_parts_mut(MaybeUninit::first_ptr_mut(&mut (*leaf).keys), len) - }; - let vals = unsafe { - slice::from_raw_parts_mut(MaybeUninit::first_ptr_mut(&mut (*leaf).vals), len) - }; - (keys, vals) - } -} - -impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Leaf> { - /// Adds a key/value pair to the end of the node. - pub fn push(&mut self, key: K, val: V) { - assert!(self.len() < CAPACITY); - - let idx = self.len(); - - unsafe { - ptr::write(self.keys_mut().get_unchecked_mut(idx), key); - ptr::write(self.vals_mut().get_unchecked_mut(idx), val); - - (*self.as_leaf_mut()).len += 1; - } - } - - /// Adds a key/value pair to the beginning of the node. - pub fn push_front(&mut self, key: K, val: V) { - assert!(self.len() < CAPACITY); - - unsafe { - slice_insert(self.keys_mut(), 0, key); - slice_insert(self.vals_mut(), 0, val); - - (*self.as_leaf_mut()).len += 1; - } - } -} - -impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> { - /// Adds a key/value pair and an edge to go to the right of that pair to - /// the end of the node. - pub fn push(&mut self, key: K, val: V, edge: Root<K, V>) { - assert!(edge.height == self.height - 1); - assert!(self.len() < CAPACITY); - - let idx = self.len(); - - unsafe { - ptr::write(self.keys_mut().get_unchecked_mut(idx), key); - ptr::write(self.vals_mut().get_unchecked_mut(idx), val); - self.as_internal_mut().edges.get_unchecked_mut(idx + 1).write(edge.node); - - (*self.as_leaf_mut()).len += 1; - - Handle::new_edge(self.reborrow_mut(), idx + 1).correct_parent_link(); - } - } - - // Unsafe because 'first' and 'after_last' must be in range - unsafe fn correct_childrens_parent_links(&mut self, first: usize, after_last: usize) { - debug_assert!(first <= self.len()); - debug_assert!(after_last <= self.len() + 1); - for i in first..after_last { - unsafe { Handle::new_edge(self.reborrow_mut(), i) }.correct_parent_link(); - } - } - - fn correct_all_childrens_parent_links(&mut self) { - let len = self.len(); - unsafe { self.correct_childrens_parent_links(0, len + 1) }; - } - - /// Adds a key/value pair and an edge to go to the left of that pair to - /// the beginning of the node. - pub fn push_front(&mut self, key: K, val: V, edge: Root<K, V>) { - assert!(edge.height == self.height - 1); - assert!(self.len() < CAPACITY); - - unsafe { - slice_insert(self.keys_mut(), 0, key); - slice_insert(self.vals_mut(), 0, val); - slice_insert( - slice::from_raw_parts_mut( - MaybeUninit::first_ptr_mut(&mut self.as_internal_mut().edges), - self.len() + 1, - ), - 0, - edge.node, - ); - - (*self.as_leaf_mut()).len += 1; - - self.correct_all_childrens_parent_links(); - } - } -} - -impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> { - /// Removes a key/value pair from the end of this node and returns the pair. - /// If this is an internal node, also removes the edge that was to the right - /// of that pair and returns the orphaned node that this edge owned with its - /// parent erased. - pub fn pop(&mut self) -> (K, V, Option<Root<K, V>>) { - assert!(self.len() > 0); - - let idx = self.len() - 1; - - unsafe { - let key = ptr::read(self.keys().get_unchecked(idx)); - let val = ptr::read(self.vals().get_unchecked(idx)); - let edge = match self.reborrow_mut().force() { - ForceResult::Leaf(_) => None, - ForceResult::Internal(internal) => { - let edge = - ptr::read(internal.as_internal().edges.get_unchecked(idx + 1).as_ptr()); - let mut new_root = Root { node: edge, height: internal.height - 1 }; - (*new_root.as_mut().as_leaf_mut()).parent = ptr::null(); - Some(new_root) - } - }; - - (*self.as_leaf_mut()).len -= 1; - (key, val, edge) - } - } - - /// Removes a key/value pair from the beginning of this node. If this is an internal node, - /// also removes the edge that was to the left of that pair. - pub fn pop_front(&mut self) -> (K, V, Option<Root<K, V>>) { - assert!(self.len() > 0); - - let old_len = self.len(); - - unsafe { - let key = slice_remove(self.keys_mut(), 0); - let val = slice_remove(self.vals_mut(), 0); - let edge = match self.reborrow_mut().force() { - ForceResult::Leaf(_) => None, - ForceResult::Internal(mut internal) => { - let edge = slice_remove( - slice::from_raw_parts_mut( - MaybeUninit::first_ptr_mut(&mut internal.as_internal_mut().edges), - old_len + 1, - ), - 0, - ); - - let mut new_root = Root { node: edge, height: internal.height - 1 }; - (*new_root.as_mut().as_leaf_mut()).parent = ptr::null(); - - for i in 0..old_len { - Handle::new_edge(internal.reborrow_mut(), i).correct_parent_link(); - } - - Some(new_root) - } - }; - - (*self.as_leaf_mut()).len -= 1; - - (key, val, edge) - } - } - - fn into_kv_pointers_mut(mut self) -> (*mut K, *mut V) { - (self.keys_mut().as_mut_ptr(), self.vals_mut().as_mut_ptr()) - } -} - -impl<BorrowType, K, V> NodeRef<BorrowType, K, V, marker::LeafOrInternal> { - /// Checks whether a node is an `Internal` node or a `Leaf` node. - pub fn force( - self, - ) -> ForceResult< - NodeRef<BorrowType, K, V, marker::Leaf>, - NodeRef<BorrowType, K, V, marker::Internal>, - > { - if self.height == 0 { - ForceResult::Leaf(NodeRef { - height: self.height, - node: self.node, - root: self.root, - _marker: PhantomData, - }) - } else { - ForceResult::Internal(NodeRef { - height: self.height, - node: self.node, - root: self.root, - _marker: PhantomData, - }) - } - } -} - -/// A reference to a specific key/value pair or edge within a node. The `Node` parameter -/// must be a `NodeRef`, while the `Type` can either be `KV` (signifying a handle on a key/value -/// pair) or `Edge` (signifying a handle on an edge). -/// -/// Note that even `Leaf` nodes can have `Edge` handles. Instead of representing a pointer to -/// a child node, these represent the spaces where child pointers would go between the key/value -/// pairs. For example, in a node with length 2, there would be 3 possible edge locations - one -/// to the left of the node, one between the two pairs, and one at the right of the node. -pub struct Handle<Node, Type> { - node: Node, - idx: usize, - _marker: PhantomData<Type>, -} - -impl<Node: Copy, Type> Copy for Handle<Node, Type> {} -// We don't need the full generality of `#[derive(Clone)]`, as the only time `Node` will be -// `Clone`able is when it is an immutable reference and therefore `Copy`. -impl<Node: Copy, Type> Clone for Handle<Node, Type> { - fn clone(&self) -> Self { - *self - } -} - -impl<Node, Type> Handle<Node, Type> { - /// Retrieves the node that contains the edge of key/value pair this handle points to. - pub fn into_node(self) -> Node { - self.node - } - - /// Returns the position of this handle in the node. - pub fn idx(&self) -> usize { - self.idx - } -} - -impl<BorrowType, K, V, NodeType> Handle<NodeRef<BorrowType, K, V, NodeType>, marker::KV> { - /// Creates a new handle to a key/value pair in `node`. - /// Unsafe because the caller must ensure that `idx < node.len()`. - pub unsafe fn new_kv(node: NodeRef<BorrowType, K, V, NodeType>, idx: usize) -> Self { - debug_assert!(idx < node.len()); - - Handle { node, idx, _marker: PhantomData } - } - - pub fn left_edge(self) -> Handle<NodeRef<BorrowType, K, V, NodeType>, marker::Edge> { - unsafe { Handle::new_edge(self.node, self.idx) } - } - - pub fn right_edge(self) -> Handle<NodeRef<BorrowType, K, V, NodeType>, marker::Edge> { - unsafe { Handle::new_edge(self.node, self.idx + 1) } - } -} - -impl<BorrowType, K, V, NodeType, HandleType> PartialEq - for Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> -{ - fn eq(&self, other: &Self) -> bool { - self.node.node == other.node.node && self.idx == other.idx - } -} - -impl<BorrowType, K, V, NodeType, HandleType> PartialOrd - for Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> -{ - fn partial_cmp(&self, other: &Self) -> Option<Ordering> { - if self.node.node == other.node.node { Some(self.idx.cmp(&other.idx)) } else { None } - } -} - -impl<BorrowType, K, V, NodeType, HandleType> - Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> -{ - /// Temporarily takes out another, immutable handle on the same location. - pub fn reborrow(&self) -> Handle<NodeRef<marker::Immut<'_>, K, V, NodeType>, HandleType> { - // We can't use Handle::new_kv or Handle::new_edge because we don't know our type - Handle { node: self.node.reborrow(), idx: self.idx, _marker: PhantomData } - } -} - -impl<'a, K, V, NodeType, HandleType> Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, HandleType> { - /// Temporarily takes out another, mutable handle on the same location. Beware, as - /// this method is very dangerous, doubly so since it may not immediately appear - /// dangerous. - /// - /// Because mutable pointers can roam anywhere around the tree and can even (through - /// `into_root_mut`) mess with the root of the tree, the result of `reborrow_mut` - /// can easily be used to make the original mutable pointer dangling, or, in the case - /// of a reborrowed handle, out of bounds. - // FIXME(@gereeter) consider adding yet another type parameter to `NodeRef` that restricts - // the use of `ascend` and `into_root_mut` on reborrowed pointers, preventing this unsafety. - pub unsafe fn reborrow_mut( - &mut self, - ) -> Handle<NodeRef<marker::Mut<'_>, K, V, NodeType>, HandleType> { - // We can't use Handle::new_kv or Handle::new_edge because we don't know our type - Handle { node: unsafe { self.node.reborrow_mut() }, idx: self.idx, _marker: PhantomData } - } -} - -impl<BorrowType, K, V, NodeType> Handle<NodeRef<BorrowType, K, V, NodeType>, marker::Edge> { - /// Creates a new handle to an edge in `node`. - /// Unsafe because the caller must ensure that `idx <= node.len()`. - pub unsafe fn new_edge(node: NodeRef<BorrowType, K, V, NodeType>, idx: usize) -> Self { - debug_assert!(idx <= node.len()); - - Handle { node, idx, _marker: PhantomData } - } - - pub fn left_kv(self) -> Result<Handle<NodeRef<BorrowType, K, V, NodeType>, marker::KV>, Self> { - if self.idx > 0 { - Ok(unsafe { Handle::new_kv(self.node, self.idx - 1) }) - } else { - Err(self) - } - } - - pub fn right_kv(self) -> Result<Handle<NodeRef<BorrowType, K, V, NodeType>, marker::KV>, Self> { - if self.idx < self.node.len() { - Ok(unsafe { Handle::new_kv(self.node, self.idx) }) - } else { - Err(self) - } - } -} - -impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge> { - /// Inserts a new key/value pair between the key/value pairs to the right and left of - /// this edge. This method assumes that there is enough space in the node for the new - /// pair to fit. - /// - /// The returned pointer points to the inserted value. - fn insert_fit(&mut self, key: K, val: V) -> *mut V { - // Necessary for correctness, but in a private module - debug_assert!(self.node.len() < CAPACITY); - - unsafe { - slice_insert(self.node.keys_mut(), self.idx, key); - slice_insert(self.node.vals_mut(), self.idx, val); - - (*self.node.as_leaf_mut()).len += 1; - - self.node.vals_mut().get_unchecked_mut(self.idx) - } - } - - /// Inserts a new key/value pair between the key/value pairs to the right and left of - /// this edge. This method splits the node if there isn't enough room. - /// - /// The returned pointer points to the inserted value. - pub fn insert(mut self, key: K, val: V) -> (InsertResult<'a, K, V, marker::Leaf>, *mut V) { - if self.node.len() < CAPACITY { - let ptr = self.insert_fit(key, val); - let kv = unsafe { Handle::new_kv(self.node, self.idx) }; - (InsertResult::Fit(kv), ptr) - } else { - let middle = unsafe { Handle::new_kv(self.node, B) }; - let (mut left, k, v, mut right) = middle.split(); - let ptr = if self.idx <= B { - unsafe { Handle::new_edge(left.reborrow_mut(), self.idx).insert_fit(key, val) } - } else { - unsafe { - Handle::new_edge( - right.as_mut().cast_unchecked::<marker::Leaf>(), - self.idx - (B + 1), - ) - .insert_fit(key, val) - } - }; - (InsertResult::Split(left, k, v, right), ptr) - } - } -} - -impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::Edge> { - /// Fixes the parent pointer and index in the child node below this edge. This is useful - /// when the ordering of edges has been changed, such as in the various `insert` methods. - fn correct_parent_link(mut self) { - let idx = self.idx as u16; - let ptr = self.node.as_internal_mut() as *mut _; - let mut child = self.descend(); - unsafe { - (*child.as_leaf_mut()).parent = ptr; - (*child.as_leaf_mut()).parent_idx.write(idx); - } - } - - /// Unsafely asserts to the compiler some static information about whether the underlying - /// node of this handle is a `Leaf` or an `Internal`. - unsafe fn cast_unchecked<NewType>( - &mut self, - ) -> Handle<NodeRef<marker::Mut<'_>, K, V, NewType>, marker::Edge> { - unsafe { Handle::new_edge(self.node.cast_unchecked(), self.idx) } - } - - /// Inserts a new key/value pair and an edge that will go to the right of that new pair - /// between this edge and the key/value pair to the right of this edge. This method assumes - /// that there is enough space in the node for the new pair to fit. - fn insert_fit(&mut self, key: K, val: V, edge: Root<K, V>) { - // Necessary for correctness, but in an internal module - debug_assert!(self.node.len() < CAPACITY); - debug_assert!(edge.height == self.node.height - 1); - - unsafe { - // This cast is a lie, but it allows us to reuse the key/value insertion logic. - self.cast_unchecked::<marker::Leaf>().insert_fit(key, val); - - slice_insert( - slice::from_raw_parts_mut( - MaybeUninit::first_ptr_mut(&mut self.node.as_internal_mut().edges), - self.node.len(), - ), - self.idx + 1, - edge.node, - ); - - for i in (self.idx + 1)..(self.node.len() + 1) { - Handle::new_edge(self.node.reborrow_mut(), i).correct_parent_link(); - } - } - } - - /// Inserts a new key/value pair and an edge that will go to the right of that new pair - /// between this edge and the key/value pair to the right of this edge. This method splits - /// the node if there isn't enough room. - pub fn insert( - mut self, - key: K, - val: V, - edge: Root<K, V>, - ) -> InsertResult<'a, K, V, marker::Internal> { - assert!(edge.height == self.node.height - 1); - - if self.node.len() < CAPACITY { - self.insert_fit(key, val, edge); - let kv = unsafe { Handle::new_kv(self.node, self.idx) }; - InsertResult::Fit(kv) - } else { - let middle = unsafe { Handle::new_kv(self.node, B) }; - let (mut left, k, v, mut right) = middle.split(); - if self.idx <= B { - unsafe { - Handle::new_edge(left.reborrow_mut(), self.idx).insert_fit(key, val, edge); - } - } else { - unsafe { - Handle::new_edge( - right.as_mut().cast_unchecked::<marker::Internal>(), - self.idx - (B + 1), - ) - .insert_fit(key, val, edge); - } - } - InsertResult::Split(left, k, v, right) - } - } -} - -impl<BorrowType, K, V> Handle<NodeRef<BorrowType, K, V, marker::Internal>, marker::Edge> { - /// Finds the node pointed to by this edge. - /// - /// `edge.descend().ascend().unwrap()` and `node.ascend().unwrap().descend()` should - /// both, upon success, do nothing. - pub fn descend(self) -> NodeRef<BorrowType, K, V, marker::LeafOrInternal> { - NodeRef { - height: self.node.height - 1, - node: unsafe { - (&*self.node.as_internal().edges.get_unchecked(self.idx).as_ptr()).as_ptr() - }, - root: self.node.root, - _marker: PhantomData, - } - } -} - -impl<'a, K: 'a, V: 'a, NodeType> Handle<NodeRef<marker::Immut<'a>, K, V, NodeType>, marker::KV> { - pub fn into_kv(self) -> (&'a K, &'a V) { - unsafe { - let (keys, vals) = self.node.into_slices(); - (keys.get_unchecked(self.idx), vals.get_unchecked(self.idx)) - } - } -} - -impl<'a, K: 'a, V: 'a, NodeType> Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, marker::KV> { - pub fn into_kv_mut(self) -> (&'a mut K, &'a mut V) { - unsafe { - let (keys, vals) = self.node.into_slices_mut(); - (keys.get_unchecked_mut(self.idx), vals.get_unchecked_mut(self.idx)) - } - } -} - -impl<'a, K, V, NodeType> Handle<NodeRef<marker::Mut<'a>, K, V, NodeType>, marker::KV> { - pub fn kv_mut(&mut self) -> (&mut K, &mut V) { - unsafe { - let (keys, vals) = self.node.reborrow_mut().into_slices_mut(); - (keys.get_unchecked_mut(self.idx), vals.get_unchecked_mut(self.idx)) - } - } -} - -impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::KV> { - /// Splits the underlying node into three parts: - /// - /// - The node is truncated to only contain the key/value pairs to the right of - /// this handle. - /// - The key and value pointed to by this handle and extracted. - /// - All the key/value pairs to the right of this handle are put into a newly - /// allocated node. - pub fn split(mut self) -> (NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, K, V, Root<K, V>) { - unsafe { - let mut new_node = Box::new(LeafNode::new()); - - let k = ptr::read(self.node.keys().get_unchecked(self.idx)); - let v = ptr::read(self.node.vals().get_unchecked(self.idx)); - - let new_len = self.node.len() - self.idx - 1; - - ptr::copy_nonoverlapping( - self.node.keys().as_ptr().add(self.idx + 1), - new_node.keys.as_mut_ptr() as *mut K, - new_len, - ); - ptr::copy_nonoverlapping( - self.node.vals().as_ptr().add(self.idx + 1), - new_node.vals.as_mut_ptr() as *mut V, - new_len, - ); - - (*self.node.as_leaf_mut()).len = self.idx as u16; - new_node.len = new_len as u16; - - (self.node, k, v, Root { node: BoxedNode::from_leaf(new_node), height: 0 }) - } - } - - /// Removes the key/value pair pointed to by this handle and returns it, along with the edge - /// between the now adjacent key/value pairs (if any) to the left and right of this handle. - pub fn remove( - mut self, - ) -> (Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>, K, V) { - unsafe { - let k = slice_remove(self.node.keys_mut(), self.idx); - let v = slice_remove(self.node.vals_mut(), self.idx); - (*self.node.as_leaf_mut()).len -= 1; - (self.left_edge(), k, v) - } - } -} - -impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::KV> { - /// Splits the underlying node into three parts: - /// - /// - The node is truncated to only contain the edges and key/value pairs to the - /// right of this handle. - /// - The key and value pointed to by this handle and extracted. - /// - All the edges and key/value pairs to the right of this handle are put into - /// a newly allocated node. - pub fn split(mut self) -> (NodeRef<marker::Mut<'a>, K, V, marker::Internal>, K, V, Root<K, V>) { - unsafe { - let mut new_node = Box::new(InternalNode::new()); - - let k = ptr::read(self.node.keys().get_unchecked(self.idx)); - let v = ptr::read(self.node.vals().get_unchecked(self.idx)); - - let height = self.node.height; - let new_len = self.node.len() - self.idx - 1; - - ptr::copy_nonoverlapping( - self.node.keys().as_ptr().add(self.idx + 1), - new_node.data.keys.as_mut_ptr() as *mut K, - new_len, - ); - ptr::copy_nonoverlapping( - self.node.vals().as_ptr().add(self.idx + 1), - new_node.data.vals.as_mut_ptr() as *mut V, - new_len, - ); - ptr::copy_nonoverlapping( - self.node.as_internal().edges.as_ptr().add(self.idx + 1), - new_node.edges.as_mut_ptr(), - new_len + 1, - ); - - (*self.node.as_leaf_mut()).len = self.idx as u16; - new_node.data.len = new_len as u16; - - let mut new_root = Root { node: BoxedNode::from_internal(new_node), height }; - - for i in 0..(new_len + 1) { - Handle::new_edge(new_root.as_mut().cast_unchecked(), i).correct_parent_link(); - } - - (self.node, k, v, new_root) - } - } - - /// Returns `true` if it is valid to call `.merge()`, i.e., whether there is enough room in - /// a node to hold the combination of the nodes to the left and right of this handle along - /// with the key/value pair at this handle. - pub fn can_merge(&self) -> bool { - (self.reborrow().left_edge().descend().len() - + self.reborrow().right_edge().descend().len() - + 1) - <= CAPACITY - } - - /// Combines the node immediately to the left of this handle, the key/value pair pointed - /// to by this handle, and the node immediately to the right of this handle into one new - /// child of the underlying node, returning an edge referencing that new child. - /// - /// Assumes that this edge `.can_merge()`. - pub fn merge( - mut self, - ) -> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::Edge> { - let self1 = unsafe { ptr::read(&self) }; - let self2 = unsafe { ptr::read(&self) }; - let mut left_node = self1.left_edge().descend(); - let left_len = left_node.len(); - let mut right_node = self2.right_edge().descend(); - let right_len = right_node.len(); - - // necessary for correctness, but in a private module - assert!(left_len + right_len < CAPACITY); - - unsafe { - ptr::write( - left_node.keys_mut().get_unchecked_mut(left_len), - slice_remove(self.node.keys_mut(), self.idx), - ); - ptr::copy_nonoverlapping( - right_node.keys().as_ptr(), - left_node.keys_mut().as_mut_ptr().add(left_len + 1), - right_len, - ); - ptr::write( - left_node.vals_mut().get_unchecked_mut(left_len), - slice_remove(self.node.vals_mut(), self.idx), - ); - ptr::copy_nonoverlapping( - right_node.vals().as_ptr(), - left_node.vals_mut().as_mut_ptr().add(left_len + 1), - right_len, - ); - - slice_remove(&mut self.node.as_internal_mut().edges, self.idx + 1); - for i in self.idx + 1..self.node.len() { - Handle::new_edge(self.node.reborrow_mut(), i).correct_parent_link(); - } - (*self.node.as_leaf_mut()).len -= 1; - - (*left_node.as_leaf_mut()).len += right_len as u16 + 1; - - let layout = if self.node.height > 1 { - ptr::copy_nonoverlapping( - right_node.cast_unchecked().as_internal().edges.as_ptr(), - left_node - .cast_unchecked() - .as_internal_mut() - .edges - .as_mut_ptr() - .add(left_len + 1), - right_len + 1, - ); - - for i in left_len + 1..left_len + right_len + 2 { - Handle::new_edge(left_node.cast_unchecked().reborrow_mut(), i) - .correct_parent_link(); - } - - Layout::new::<InternalNode<K, V>>() - } else { - Layout::new::<LeafNode<K, V>>() - }; - Global.dealloc(right_node.node.cast(), layout); - - Handle::new_edge(self.node, self.idx) - } - } - - /// This removes a key/value pair from the left child and places it in the key/value storage - /// pointed to by this handle while pushing the old key/value pair of this handle into the right - /// child. - pub fn steal_left(&mut self) { - unsafe { - let (k, v, edge) = self.reborrow_mut().left_edge().descend().pop(); - - let k = mem::replace(self.reborrow_mut().into_kv_mut().0, k); - let v = mem::replace(self.reborrow_mut().into_kv_mut().1, v); - - match self.reborrow_mut().right_edge().descend().force() { - ForceResult::Leaf(mut leaf) => leaf.push_front(k, v), - ForceResult::Internal(mut internal) => internal.push_front(k, v, edge.unwrap()), - } - } - } - - /// This removes a key/value pair from the right child and places it in the key/value storage - /// pointed to by this handle while pushing the old key/value pair of this handle into the left - /// child. - pub fn steal_right(&mut self) { - unsafe { - let (k, v, edge) = self.reborrow_mut().right_edge().descend().pop_front(); - - let k = mem::replace(self.reborrow_mut().into_kv_mut().0, k); - let v = mem::replace(self.reborrow_mut().into_kv_mut().1, v); - - match self.reborrow_mut().left_edge().descend().force() { - ForceResult::Leaf(mut leaf) => leaf.push(k, v), - ForceResult::Internal(mut internal) => internal.push(k, v, edge.unwrap()), - } - } - } - - /// This does stealing similar to `steal_left` but steals multiple elements at once. - pub fn bulk_steal_left(&mut self, count: usize) { - unsafe { - let mut left_node = ptr::read(self).left_edge().descend(); - let left_len = left_node.len(); - let mut right_node = ptr::read(self).right_edge().descend(); - let right_len = right_node.len(); - - // Make sure that we may steal safely. - assert!(right_len + count <= CAPACITY); - assert!(left_len >= count); - - let new_left_len = left_len - count; - - // Move data. - { - let left_kv = left_node.reborrow_mut().into_kv_pointers_mut(); - let right_kv = right_node.reborrow_mut().into_kv_pointers_mut(); - let parent_kv = { - let kv = self.reborrow_mut().into_kv_mut(); - (kv.0 as *mut K, kv.1 as *mut V) - }; - - // Make room for stolen elements in the right child. - ptr::copy(right_kv.0, right_kv.0.add(count), right_len); - ptr::copy(right_kv.1, right_kv.1.add(count), right_len); - - // Move elements from the left child to the right one. - move_kv(left_kv, new_left_len + 1, right_kv, 0, count - 1); - - // Move parent's key/value pair to the right child. - move_kv(parent_kv, 0, right_kv, count - 1, 1); - - // Move the left-most stolen pair to the parent. - move_kv(left_kv, new_left_len, parent_kv, 0, 1); - } - - (*left_node.reborrow_mut().as_leaf_mut()).len -= count as u16; - (*right_node.reborrow_mut().as_leaf_mut()).len += count as u16; - - match (left_node.force(), right_node.force()) { - (ForceResult::Internal(left), ForceResult::Internal(mut right)) => { - // Make room for stolen edges. - let right_edges = right.reborrow_mut().as_internal_mut().edges.as_mut_ptr(); - ptr::copy(right_edges, right_edges.add(count), right_len + 1); - right.correct_childrens_parent_links(count, count + right_len + 1); - - move_edges(left, new_left_len + 1, right, 0, count); - } - (ForceResult::Leaf(_), ForceResult::Leaf(_)) => {} - _ => { - unreachable!(); - } - } - } - } - - /// The symmetric clone of `bulk_steal_left`. - pub fn bulk_steal_right(&mut self, count: usize) { - unsafe { - let mut left_node = ptr::read(self).left_edge().descend(); - let left_len = left_node.len(); - let mut right_node = ptr::read(self).right_edge().descend(); - let right_len = right_node.len(); - - // Make sure that we may steal safely. - assert!(left_len + count <= CAPACITY); - assert!(right_len >= count); - - let new_right_len = right_len - count; - - // Move data. - { - let left_kv = left_node.reborrow_mut().into_kv_pointers_mut(); - let right_kv = right_node.reborrow_mut().into_kv_pointers_mut(); - let parent_kv = { - let kv = self.reborrow_mut().into_kv_mut(); - (kv.0 as *mut K, kv.1 as *mut V) - }; - - // Move parent's key/value pair to the left child. - move_kv(parent_kv, 0, left_kv, left_len, 1); - - // Move elements from the right child to the left one. - move_kv(right_kv, 0, left_kv, left_len + 1, count - 1); - - // Move the right-most stolen pair to the parent. - move_kv(right_kv, count - 1, parent_kv, 0, 1); - - // Fix right indexing - ptr::copy(right_kv.0.add(count), right_kv.0, new_right_len); - ptr::copy(right_kv.1.add(count), right_kv.1, new_right_len); - } - - (*left_node.reborrow_mut().as_leaf_mut()).len += count as u16; - (*right_node.reborrow_mut().as_leaf_mut()).len -= count as u16; - - match (left_node.force(), right_node.force()) { - (ForceResult::Internal(left), ForceResult::Internal(mut right)) => { - move_edges(right.reborrow_mut(), 0, left, left_len + 1, count); - - // Fix right indexing. - let right_edges = right.reborrow_mut().as_internal_mut().edges.as_mut_ptr(); - ptr::copy(right_edges.add(count), right_edges, new_right_len + 1); - right.correct_childrens_parent_links(0, new_right_len + 1); - } - (ForceResult::Leaf(_), ForceResult::Leaf(_)) => {} - _ => { - unreachable!(); - } - } - } - } -} - -unsafe fn move_kv<K, V>( - source: (*mut K, *mut V), - source_offset: usize, - dest: (*mut K, *mut V), - dest_offset: usize, - count: usize, -) { - unsafe { - ptr::copy_nonoverlapping(source.0.add(source_offset), dest.0.add(dest_offset), count); - ptr::copy_nonoverlapping(source.1.add(source_offset), dest.1.add(dest_offset), count); - } -} - -// Source and destination must have the same height. -unsafe fn move_edges<K, V>( - mut source: NodeRef<marker::Mut<'_>, K, V, marker::Internal>, - source_offset: usize, - mut dest: NodeRef<marker::Mut<'_>, K, V, marker::Internal>, - dest_offset: usize, - count: usize, -) { - let source_ptr = source.as_internal_mut().edges.as_mut_ptr(); - let dest_ptr = dest.as_internal_mut().edges.as_mut_ptr(); - unsafe { - ptr::copy_nonoverlapping(source_ptr.add(source_offset), dest_ptr.add(dest_offset), count); - dest.correct_childrens_parent_links(dest_offset, dest_offset + count); - } -} - -impl<BorrowType, K, V> Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge> { - pub fn forget_node_type( - self, - ) -> Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, marker::Edge> { - unsafe { Handle::new_edge(self.node.forget_type(), self.idx) } - } -} - -impl<BorrowType, K, V> Handle<NodeRef<BorrowType, K, V, marker::Internal>, marker::Edge> { - pub fn forget_node_type( - self, - ) -> Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, marker::Edge> { - unsafe { Handle::new_edge(self.node.forget_type(), self.idx) } - } -} - -impl<BorrowType, K, V> Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::KV> { - pub fn forget_node_type( - self, - ) -> Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, marker::KV> { - unsafe { Handle::new_kv(self.node.forget_type(), self.idx) } - } -} - -impl<BorrowType, K, V, HandleType> - Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, HandleType> -{ - /// Checks whether the underlying node is an `Internal` node or a `Leaf` node. - pub fn force( - self, - ) -> ForceResult< - Handle<NodeRef<BorrowType, K, V, marker::Leaf>, HandleType>, - Handle<NodeRef<BorrowType, K, V, marker::Internal>, HandleType>, - > { - match self.node.force() { - ForceResult::Leaf(node) => { - ForceResult::Leaf(Handle { node, idx: self.idx, _marker: PhantomData }) - } - ForceResult::Internal(node) => { - ForceResult::Internal(Handle { node, idx: self.idx, _marker: PhantomData }) - } - } - } -} - -impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::Edge> { - /// Move the suffix after `self` from one node to another one. `right` must be empty. - /// The first edge of `right` remains unchanged. - pub fn move_suffix( - &mut self, - right: &mut NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, - ) { - unsafe { - let left_new_len = self.idx; - let mut left_node = self.reborrow_mut().into_node(); - - let right_new_len = left_node.len() - left_new_len; - let mut right_node = right.reborrow_mut(); - - assert!(right_node.len() == 0); - assert!(left_node.height == right_node.height); - - if right_new_len > 0 { - let left_kv = left_node.reborrow_mut().into_kv_pointers_mut(); - let right_kv = right_node.reborrow_mut().into_kv_pointers_mut(); - - move_kv(left_kv, left_new_len, right_kv, 0, right_new_len); - - (*left_node.reborrow_mut().as_leaf_mut()).len = left_new_len as u16; - (*right_node.reborrow_mut().as_leaf_mut()).len = right_new_len as u16; - - match (left_node.force(), right_node.force()) { - (ForceResult::Internal(left), ForceResult::Internal(right)) => { - move_edges(left, left_new_len + 1, right, 1, right_new_len); - } - (ForceResult::Leaf(_), ForceResult::Leaf(_)) => {} - _ => { - unreachable!(); - } - } - } - } - } -} - -pub enum ForceResult<Leaf, Internal> { - Leaf(Leaf), - Internal(Internal), -} - -pub enum InsertResult<'a, K, V, Type> { - Fit(Handle<NodeRef<marker::Mut<'a>, K, V, Type>, marker::KV>), - Split(NodeRef<marker::Mut<'a>, K, V, Type>, K, V, Root<K, V>), -} - -pub mod marker { - use core::marker::PhantomData; - - pub enum Leaf {} - pub enum Internal {} - pub enum LeafOrInternal {} - - pub enum Owned {} - pub struct Immut<'a>(PhantomData<&'a ()>); - pub struct Mut<'a>(PhantomData<&'a mut ()>); - - pub enum KV {} - pub enum Edge {} -} - -unsafe fn slice_insert<T>(slice: &mut [T], idx: usize, val: T) { - unsafe { - ptr::copy(slice.as_ptr().add(idx), slice.as_mut_ptr().add(idx + 1), slice.len() - idx); - ptr::write(slice.get_unchecked_mut(idx), val); - } -} - -unsafe fn slice_remove<T>(slice: &mut [T], idx: usize) -> T { - unsafe { - let ret = ptr::read(slice.get_unchecked(idx)); - ptr::copy(slice.as_ptr().add(idx + 1), slice.as_mut_ptr().add(idx), slice.len() - idx - 1); - ret - } -} diff --git a/src/liballoc/collections/btree/search.rs b/src/liballoc/collections/btree/search.rs deleted file mode 100644 index 4e80f7f21eb..00000000000 --- a/src/liballoc/collections/btree/search.rs +++ /dev/null @@ -1,83 +0,0 @@ -use core::borrow::Borrow; -use core::cmp::Ordering; - -use super::node::{marker, ForceResult::*, Handle, NodeRef}; - -use SearchResult::*; - -pub enum SearchResult<BorrowType, K, V, FoundType, GoDownType> { - Found(Handle<NodeRef<BorrowType, K, V, FoundType>, marker::KV>), - GoDown(Handle<NodeRef<BorrowType, K, V, GoDownType>, marker::Edge>), -} - -/// Looks up a given key in a (sub)tree headed by the given node, recursively. -/// Returns a `Found` with the handle of the matching KV, if any. Otherwise, -/// returns a `GoDown` with the handle of the possible leaf edge where the key -/// belongs. -pub fn search_tree<BorrowType, K, V, Q: ?Sized>( - mut node: NodeRef<BorrowType, K, V, marker::LeafOrInternal>, - key: &Q, -) -> SearchResult<BorrowType, K, V, marker::LeafOrInternal, marker::Leaf> -where - Q: Ord, - K: Borrow<Q>, -{ - loop { - match search_node(node, key) { - Found(handle) => return Found(handle), - GoDown(handle) => match handle.force() { - Leaf(leaf) => return GoDown(leaf), - Internal(internal) => { - node = internal.descend(); - continue; - } - }, - } - } -} - -/// Looks up a given key in a given node, without recursion. -/// Returns a `Found` with the handle of the matching KV, if any. Otherwise, -/// returns a `GoDown` with the handle of the edge where the key might be found. -/// If the node is a leaf, a `GoDown` edge is not an actual edge but a possible edge. -pub fn search_node<BorrowType, K, V, Type, Q: ?Sized>( - node: NodeRef<BorrowType, K, V, Type>, - key: &Q, -) -> SearchResult<BorrowType, K, V, Type, Type> -where - Q: Ord, - K: Borrow<Q>, -{ - match search_linear(&node, key) { - (idx, true) => Found(unsafe { Handle::new_kv(node, idx) }), - (idx, false) => SearchResult::GoDown(unsafe { Handle::new_edge(node, idx) }), - } -} - -/// Returns the index in the node at which the key (or an equivalent) exists -/// or could exist, and whether it exists in the node itself. If it doesn't -/// exist in the node itself, it may exist in the subtree with that index -/// (if the node has subtrees). If the key doesn't exist in node or subtree, -/// the returned index is the position or subtree where the key belongs. -fn search_linear<BorrowType, K, V, Type, Q: ?Sized>( - node: &NodeRef<BorrowType, K, V, Type>, - key: &Q, -) -> (usize, bool) -where - Q: Ord, - K: Borrow<Q>, -{ - // This function is defined over all borrow types (immutable, mutable, owned). - // Using `keys()` is fine here even if BorrowType is mutable, as all we return - // is an index -- not a reference. - let len = node.len(); - let keys = node.keys(); - for (i, k) in keys.iter().enumerate() { - match key.cmp(k.borrow()) { - Ordering::Greater => {} - Ordering::Equal => return (i, true), - Ordering::Less => return (i, false), - } - } - (len, false) -} diff --git a/src/liballoc/collections/btree/set.rs b/src/liballoc/collections/btree/set.rs deleted file mode 100644 index 35f4ef1d9b4..00000000000 --- a/src/liballoc/collections/btree/set.rs +++ /dev/null @@ -1,1574 +0,0 @@ -// This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface -// to TreeMap - -use core::borrow::Borrow; -use core::cmp::Ordering::{Equal, Greater, Less}; -use core::cmp::{max, min}; -use core::fmt::{self, Debug}; -use core::iter::{FromIterator, FusedIterator, Peekable}; -use core::ops::{BitAnd, BitOr, BitXor, RangeBounds, Sub}; - -use super::map::{BTreeMap, Keys}; -use super::Recover; - -// FIXME(conventions): implement bounded iterators - -/// A set based on a B-Tree. -/// -/// See [`BTreeMap`]'s documentation for a detailed discussion of this collection's performance -/// benefits and drawbacks. -/// -/// It is a logic error for an item to be modified in such a way that the item's ordering relative -/// to any other item, as determined by the [`Ord`] trait, changes while it is in the set. This is -/// normally only possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code. -/// -/// [`Ord`]: core::cmp::Ord -/// [`Cell`]: core::cell::Cell -/// [`RefCell`]: core::cell::RefCell -/// -/// # Examples -/// -/// ``` -/// use std::collections::BTreeSet; -/// -/// // Type inference lets us omit an explicit type signature (which -/// // would be `BTreeSet<&str>` in this example). -/// let mut books = BTreeSet::new(); -/// -/// // Add some books. -/// books.insert("A Dance With Dragons"); -/// books.insert("To Kill a Mockingbird"); -/// books.insert("The Odyssey"); -/// books.insert("The Great Gatsby"); -/// -/// // Check for a specific one. -/// if !books.contains("The Winds of Winter") { -/// println!("We have {} books, but The Winds of Winter ain't one.", -/// books.len()); -/// } -/// -/// // Remove a book. -/// books.remove("The Odyssey"); -/// -/// // Iterate over everything. -/// for book in &books { -/// println!("{}", book); -/// } -/// ``` -#[derive(Hash, PartialEq, Eq, Ord, PartialOrd)] -#[stable(feature = "rust1", since = "1.0.0")] -pub struct BTreeSet<T> { - map: BTreeMap<T, ()>, -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Clone> Clone for BTreeSet<T> { - fn clone(&self) -> Self { - BTreeSet { map: self.map.clone() } - } - - fn clone_from(&mut self, other: &Self) { - self.map.clone_from(&other.map); - } -} - -/// An iterator over the items of a `BTreeSet`. -/// -/// This `struct` is created by the [`iter`] method on [`BTreeSet`]. -/// See its documentation for more. -/// -/// [`iter`]: BTreeSet::iter -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Iter<'a, T: 'a> { - iter: Keys<'a, T, ()>, -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("Iter").field(&self.iter.clone()).finish() - } -} - -/// An owning iterator over the items of a `BTreeSet`. -/// -/// This `struct` is created by the [`into_iter`] method on [`BTreeSet`] -/// (provided by the `IntoIterator` trait). See its documentation for more. -/// -/// [`into_iter`]: BTreeSet#method.into_iter -#[stable(feature = "rust1", since = "1.0.0")] -#[derive(Debug)] -pub struct IntoIter<T> { - iter: super::map::IntoIter<T, ()>, -} - -/// An iterator over a sub-range of items in a `BTreeSet`. -/// -/// This `struct` is created by the [`range`] method on [`BTreeSet`]. -/// See its documentation for more. -/// -/// [`range`]: BTreeSet::range -#[derive(Debug)] -#[stable(feature = "btree_range", since = "1.17.0")] -pub struct Range<'a, T: 'a> { - iter: super::map::Range<'a, T, ()>, -} - -/// Core of SymmetricDifference and Union. -/// More efficient than btree.map.MergeIter, -/// and crucially for SymmetricDifference, nexts() reports on both sides. -#[derive(Clone)] -struct MergeIterInner<I> -where - I: Iterator, - I::Item: Copy, -{ - a: I, - b: I, - peeked: Option<MergeIterPeeked<I>>, -} - -#[derive(Copy, Clone, Debug)] -enum MergeIterPeeked<I: Iterator> { - A(I::Item), - B(I::Item), -} - -impl<I> MergeIterInner<I> -where - I: ExactSizeIterator + FusedIterator, - I::Item: Copy + Ord, -{ - fn new(a: I, b: I) -> Self { - MergeIterInner { a, b, peeked: None } - } - - fn nexts(&mut self) -> (Option<I::Item>, Option<I::Item>) { - let mut a_next = match self.peeked { - Some(MergeIterPeeked::A(next)) => Some(next), - _ => self.a.next(), - }; - let mut b_next = match self.peeked { - Some(MergeIterPeeked::B(next)) => Some(next), - _ => self.b.next(), - }; - let ord = match (a_next, b_next) { - (None, None) => Equal, - (_, None) => Less, - (None, _) => Greater, - (Some(a1), Some(b1)) => a1.cmp(&b1), - }; - self.peeked = match ord { - Less => b_next.take().map(MergeIterPeeked::B), - Equal => None, - Greater => a_next.take().map(MergeIterPeeked::A), - }; - (a_next, b_next) - } - - fn lens(&self) -> (usize, usize) { - match self.peeked { - Some(MergeIterPeeked::A(_)) => (1 + self.a.len(), self.b.len()), - Some(MergeIterPeeked::B(_)) => (self.a.len(), 1 + self.b.len()), - _ => (self.a.len(), self.b.len()), - } - } -} - -impl<I> Debug for MergeIterInner<I> -where - I: Iterator + Debug, - I::Item: Copy + Debug, -{ - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("MergeIterInner").field(&self.a).field(&self.b).finish() - } -} - -/// A lazy iterator producing elements in the difference of `BTreeSet`s. -/// -/// This `struct` is created by the [`difference`] method on [`BTreeSet`]. -/// See its documentation for more. -/// -/// [`difference`]: BTreeSet::difference -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Difference<'a, T: 'a> { - inner: DifferenceInner<'a, T>, -} -#[derive(Debug)] -enum DifferenceInner<'a, T: 'a> { - Stitch { - // iterate all of `self` and some of `other`, spotting matches along the way - self_iter: Iter<'a, T>, - other_iter: Peekable<Iter<'a, T>>, - }, - Search { - // iterate `self`, look up in `other` - self_iter: Iter<'a, T>, - other_set: &'a BTreeSet<T>, - }, - Iterate(Iter<'a, T>), // simply produce all values in `self` -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<T: fmt::Debug> fmt::Debug for Difference<'_, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("Difference").field(&self.inner).finish() - } -} - -/// A lazy iterator producing elements in the symmetric difference of `BTreeSet`s. -/// -/// This `struct` is created by the [`symmetric_difference`] method on -/// [`BTreeSet`]. See its documentation for more. -/// -/// [`symmetric_difference`]: BTreeSet::symmetric_difference -#[stable(feature = "rust1", since = "1.0.0")] -pub struct SymmetricDifference<'a, T: 'a>(MergeIterInner<Iter<'a, T>>); - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<T: fmt::Debug> fmt::Debug for SymmetricDifference<'_, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("SymmetricDifference").field(&self.0).finish() - } -} - -/// A lazy iterator producing elements in the intersection of `BTreeSet`s. -/// -/// This `struct` is created by the [`intersection`] method on [`BTreeSet`]. -/// See its documentation for more. -/// -/// [`intersection`]: BTreeSet::intersection -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Intersection<'a, T: 'a> { - inner: IntersectionInner<'a, T>, -} -#[derive(Debug)] -enum IntersectionInner<'a, T: 'a> { - Stitch { - // iterate similarly sized sets jointly, spotting matches along the way - a: Iter<'a, T>, - b: Iter<'a, T>, - }, - Search { - // iterate a small set, look up in the large set - small_iter: Iter<'a, T>, - large_set: &'a BTreeSet<T>, - }, - Answer(Option<&'a T>), // return a specific value or emptiness -} - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<T: fmt::Debug> fmt::Debug for Intersection<'_, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("Intersection").field(&self.inner).finish() - } -} - -/// A lazy iterator producing elements in the union of `BTreeSet`s. -/// -/// This `struct` is created by the [`union`] method on [`BTreeSet`]. -/// See its documentation for more. -/// -/// [`union`]: BTreeSet::union -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Union<'a, T: 'a>(MergeIterInner<Iter<'a, T>>); - -#[stable(feature = "collection_debug", since = "1.17.0")] -impl<T: fmt::Debug> fmt::Debug for Union<'_, T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("Union").field(&self.0).finish() - } -} - -// This constant is used by functions that compare two sets. -// It estimates the relative size at which searching performs better -// than iterating, based on the benchmarks in -// https://github.com/ssomers/rust_bench_btreeset_intersection; -// It's used to divide rather than multiply sizes, to rule out overflow, -// and it's a power of two to make that division cheap. -const ITER_PERFORMANCE_TIPPING_SIZE_DIFF: usize = 16; - -impl<T: Ord> BTreeSet<T> { - /// Makes a new `BTreeSet` with a reasonable choice of B. - /// - /// # Examples - /// - /// ``` - /// # #![allow(unused_mut)] - /// use std::collections::BTreeSet; - /// - /// let mut set: BTreeSet<i32> = BTreeSet::new(); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")] - pub const fn new() -> BTreeSet<T> { - BTreeSet { map: BTreeMap::new() } - } - - /// Constructs a double-ended iterator over a sub-range of elements in the set. - /// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will - /// yield elements from min (inclusive) to max (exclusive). - /// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example - /// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive - /// range from 4 to 10. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// use std::ops::Bound::Included; - /// - /// let mut set = BTreeSet::new(); - /// set.insert(3); - /// set.insert(5); - /// set.insert(8); - /// for &elem in set.range((Included(&4), Included(&8))) { - /// println!("{}", elem); - /// } - /// assert_eq!(Some(&5), set.range(4..).next()); - /// ``` - #[stable(feature = "btree_range", since = "1.17.0")] - pub fn range<K: ?Sized, R>(&self, range: R) -> Range<'_, T> - where - K: Ord, - T: Borrow<K>, - R: RangeBounds<K>, - { - Range { iter: self.map.range(range) } - } - - /// Visits the values representing the difference, - /// i.e., the values that are in `self` but not in `other`, - /// in ascending order. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut a = BTreeSet::new(); - /// a.insert(1); - /// a.insert(2); - /// - /// let mut b = BTreeSet::new(); - /// b.insert(2); - /// b.insert(3); - /// - /// let diff: Vec<_> = a.difference(&b).cloned().collect(); - /// assert_eq!(diff, [1]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T> { - let (self_min, self_max) = - if let (Some(self_min), Some(self_max)) = (self.first(), self.last()) { - (self_min, self_max) - } else { - return Difference { inner: DifferenceInner::Iterate(self.iter()) }; - }; - let (other_min, other_max) = - if let (Some(other_min), Some(other_max)) = (other.first(), other.last()) { - (other_min, other_max) - } else { - return Difference { inner: DifferenceInner::Iterate(self.iter()) }; - }; - Difference { - inner: match (self_min.cmp(other_max), self_max.cmp(other_min)) { - (Greater, _) | (_, Less) => DifferenceInner::Iterate(self.iter()), - (Equal, _) => { - let mut self_iter = self.iter(); - self_iter.next(); - DifferenceInner::Iterate(self_iter) - } - (_, Equal) => { - let mut self_iter = self.iter(); - self_iter.next_back(); - DifferenceInner::Iterate(self_iter) - } - _ if self.len() <= other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF => { - DifferenceInner::Search { self_iter: self.iter(), other_set: other } - } - _ => DifferenceInner::Stitch { - self_iter: self.iter(), - other_iter: other.iter().peekable(), - }, - }, - } - } - - /// Visits the values representing the symmetric difference, - /// i.e., the values that are in `self` or in `other` but not in both, - /// in ascending order. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut a = BTreeSet::new(); - /// a.insert(1); - /// a.insert(2); - /// - /// let mut b = BTreeSet::new(); - /// b.insert(2); - /// b.insert(3); - /// - /// let sym_diff: Vec<_> = a.symmetric_difference(&b).cloned().collect(); - /// assert_eq!(sym_diff, [1, 3]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn symmetric_difference<'a>( - &'a self, - other: &'a BTreeSet<T>, - ) -> SymmetricDifference<'a, T> { - SymmetricDifference(MergeIterInner::new(self.iter(), other.iter())) - } - - /// Visits the values representing the intersection, - /// i.e., the values that are both in `self` and `other`, - /// in ascending order. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut a = BTreeSet::new(); - /// a.insert(1); - /// a.insert(2); - /// - /// let mut b = BTreeSet::new(); - /// b.insert(2); - /// b.insert(3); - /// - /// let intersection: Vec<_> = a.intersection(&b).cloned().collect(); - /// assert_eq!(intersection, [2]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn intersection<'a>(&'a self, other: &'a BTreeSet<T>) -> Intersection<'a, T> { - let (self_min, self_max) = - if let (Some(self_min), Some(self_max)) = (self.first(), self.last()) { - (self_min, self_max) - } else { - return Intersection { inner: IntersectionInner::Answer(None) }; - }; - let (other_min, other_max) = - if let (Some(other_min), Some(other_max)) = (other.first(), other.last()) { - (other_min, other_max) - } else { - return Intersection { inner: IntersectionInner::Answer(None) }; - }; - Intersection { - inner: match (self_min.cmp(other_max), self_max.cmp(other_min)) { - (Greater, _) | (_, Less) => IntersectionInner::Answer(None), - (Equal, _) => IntersectionInner::Answer(Some(self_min)), - (_, Equal) => IntersectionInner::Answer(Some(self_max)), - _ if self.len() <= other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF => { - IntersectionInner::Search { small_iter: self.iter(), large_set: other } - } - _ if other.len() <= self.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF => { - IntersectionInner::Search { small_iter: other.iter(), large_set: self } - } - _ => IntersectionInner::Stitch { a: self.iter(), b: other.iter() }, - }, - } - } - - /// Visits the values representing the union, - /// i.e., all the values in `self` or `other`, without duplicates, - /// in ascending order. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut a = BTreeSet::new(); - /// a.insert(1); - /// - /// let mut b = BTreeSet::new(); - /// b.insert(2); - /// - /// let union: Vec<_> = a.union(&b).cloned().collect(); - /// assert_eq!(union, [1, 2]); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn union<'a>(&'a self, other: &'a BTreeSet<T>) -> Union<'a, T> { - Union(MergeIterInner::new(self.iter(), other.iter())) - } - - /// Clears the set, removing all values. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut v = BTreeSet::new(); - /// v.insert(1); - /// v.clear(); - /// assert!(v.is_empty()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn clear(&mut self) { - self.map.clear() - } - - /// Returns `true` if the set contains a value. - /// - /// The value may be any borrowed form of the set's value type, - /// but the ordering on the borrowed form *must* match the - /// ordering on the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect(); - /// assert_eq!(set.contains(&1), true); - /// assert_eq!(set.contains(&4), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool - where - T: Borrow<Q>, - Q: Ord, - { - self.map.contains_key(value) - } - - /// Returns a reference to the value in the set, if any, that is equal to the given value. - /// - /// The value may be any borrowed form of the set's value type, - /// but the ordering on the borrowed form *must* match the - /// ordering on the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect(); - /// assert_eq!(set.get(&2), Some(&2)); - /// assert_eq!(set.get(&4), None); - /// ``` - #[stable(feature = "set_recovery", since = "1.9.0")] - pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T> - where - T: Borrow<Q>, - Q: Ord, - { - Recover::get(&self.map, value) - } - - /// Returns `true` if `self` has no elements in common with `other`. - /// This is equivalent to checking for an empty intersection. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let a: BTreeSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let mut b = BTreeSet::new(); - /// - /// assert_eq!(a.is_disjoint(&b), true); - /// b.insert(4); - /// assert_eq!(a.is_disjoint(&b), true); - /// b.insert(1); - /// assert_eq!(a.is_disjoint(&b), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_disjoint(&self, other: &BTreeSet<T>) -> bool { - self.intersection(other).next().is_none() - } - - /// Returns `true` if the set is a subset of another, - /// i.e., `other` contains at least all the values in `self`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let sup: BTreeSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let mut set = BTreeSet::new(); - /// - /// assert_eq!(set.is_subset(&sup), true); - /// set.insert(2); - /// assert_eq!(set.is_subset(&sup), true); - /// set.insert(4); - /// assert_eq!(set.is_subset(&sup), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_subset(&self, other: &BTreeSet<T>) -> bool { - // Same result as self.difference(other).next().is_none() - // but the code below is faster (hugely in some cases). - if self.len() > other.len() { - return false; - } - let (self_min, self_max) = - if let (Some(self_min), Some(self_max)) = (self.first(), self.last()) { - (self_min, self_max) - } else { - return true; // self is empty - }; - let (other_min, other_max) = - if let (Some(other_min), Some(other_max)) = (other.first(), other.last()) { - (other_min, other_max) - } else { - return false; // other is empty - }; - let mut self_iter = self.iter(); - match self_min.cmp(other_min) { - Less => return false, - Equal => { - self_iter.next(); - } - Greater => (), - } - match self_max.cmp(other_max) { - Greater => return false, - Equal => { - self_iter.next_back(); - } - Less => (), - } - if self_iter.len() <= other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF { - for next in self_iter { - if !other.contains(next) { - return false; - } - } - } else { - let mut other_iter = other.iter(); - other_iter.next(); - other_iter.next_back(); - let mut self_next = self_iter.next(); - while let Some(self1) = self_next { - match other_iter.next().map_or(Less, |other1| self1.cmp(other1)) { - Less => return false, - Equal => self_next = self_iter.next(), - Greater => (), - } - } - } - true - } - - /// Returns `true` if the set is a superset of another, - /// i.e., `self` contains at least all the values in `other`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let sub: BTreeSet<_> = [1, 2].iter().cloned().collect(); - /// let mut set = BTreeSet::new(); - /// - /// assert_eq!(set.is_superset(&sub), false); - /// - /// set.insert(0); - /// set.insert(1); - /// assert_eq!(set.is_superset(&sub), false); - /// - /// set.insert(2); - /// assert_eq!(set.is_superset(&sub), true); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_superset(&self, other: &BTreeSet<T>) -> bool { - other.is_subset(self) - } - - /// Returns a reference to the first value in the set, if any. - /// This value is always the minimum of all values in the set. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeSet; - /// - /// let mut map = BTreeSet::new(); - /// assert_eq!(map.first(), None); - /// map.insert(1); - /// assert_eq!(map.first(), Some(&1)); - /// map.insert(2); - /// assert_eq!(map.first(), Some(&1)); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn first(&self) -> Option<&T> { - self.map.first_key_value().map(|(k, _)| k) - } - - /// Returns a reference to the last value in the set, if any. - /// This value is always the maximum of all values in the set. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeSet; - /// - /// let mut map = BTreeSet::new(); - /// assert_eq!(map.first(), None); - /// map.insert(1); - /// assert_eq!(map.last(), Some(&1)); - /// map.insert(2); - /// assert_eq!(map.last(), Some(&2)); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn last(&self) -> Option<&T> { - self.map.last_key_value().map(|(k, _)| k) - } - - /// Removes the first value from the set and returns it, if any. - /// The first value is always the minimum value in the set. - /// - /// # Examples - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeSet; - /// - /// let mut set = BTreeSet::new(); - /// - /// set.insert(1); - /// while let Some(n) = set.pop_first() { - /// assert_eq!(n, 1); - /// } - /// assert!(set.is_empty()); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn pop_first(&mut self) -> Option<T> { - self.map.first_entry().map(|entry| entry.remove_entry().0) - } - - /// Removes the last value from the set and returns it, if any. - /// The last value is always the maximum value in the set. - /// - /// # Examples - /// - /// ``` - /// #![feature(map_first_last)] - /// use std::collections::BTreeSet; - /// - /// let mut set = BTreeSet::new(); - /// - /// set.insert(1); - /// while let Some(n) = set.pop_last() { - /// assert_eq!(n, 1); - /// } - /// assert!(set.is_empty()); - /// ``` - #[unstable(feature = "map_first_last", issue = "62924")] - pub fn pop_last(&mut self) -> Option<T> { - self.map.last_entry().map(|entry| entry.remove_entry().0) - } - - /// Adds a value to the set. - /// - /// If the set did not have this value present, `true` is returned. - /// - /// If the set did have this value present, `false` is returned, and the - /// entry is not updated. See the [module-level documentation] for more. - /// - /// [module-level documentation]: index.html#insert-and-complex-keys - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut set = BTreeSet::new(); - /// - /// assert_eq!(set.insert(2), true); - /// assert_eq!(set.insert(2), false); - /// assert_eq!(set.len(), 1); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn insert(&mut self, value: T) -> bool { - self.map.insert(value, ()).is_none() - } - - /// Adds a value to the set, replacing the existing value, if any, that is equal to the given - /// one. Returns the replaced value. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut set = BTreeSet::new(); - /// set.insert(Vec::<i32>::new()); - /// - /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 0); - /// set.replace(Vec::with_capacity(10)); - /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 10); - /// ``` - #[stable(feature = "set_recovery", since = "1.9.0")] - pub fn replace(&mut self, value: T) -> Option<T> { - Recover::replace(&mut self.map, value) - } - - /// Removes a value from the set. Returns whether the value was - /// present in the set. - /// - /// The value may be any borrowed form of the set's value type, - /// but the ordering on the borrowed form *must* match the - /// ordering on the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut set = BTreeSet::new(); - /// - /// set.insert(2); - /// assert_eq!(set.remove(&2), true); - /// assert_eq!(set.remove(&2), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool - where - T: Borrow<Q>, - Q: Ord, - { - self.map.remove(value).is_some() - } - - /// Removes and returns the value in the set, if any, that is equal to the given one. - /// - /// The value may be any borrowed form of the set's value type, - /// but the ordering on the borrowed form *must* match the - /// ordering on the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut set: BTreeSet<_> = [1, 2, 3].iter().cloned().collect(); - /// assert_eq!(set.take(&2), Some(2)); - /// assert_eq!(set.take(&2), None); - /// ``` - #[stable(feature = "set_recovery", since = "1.9.0")] - pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> - where - T: Borrow<Q>, - Q: Ord, - { - Recover::take(&mut self.map, value) - } - - /// Moves all elements from `other` into `Self`, leaving `other` empty. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut a = BTreeSet::new(); - /// a.insert(1); - /// a.insert(2); - /// a.insert(3); - /// - /// let mut b = BTreeSet::new(); - /// b.insert(3); - /// b.insert(4); - /// b.insert(5); - /// - /// a.append(&mut b); - /// - /// assert_eq!(a.len(), 5); - /// assert_eq!(b.len(), 0); - /// - /// assert!(a.contains(&1)); - /// assert!(a.contains(&2)); - /// assert!(a.contains(&3)); - /// assert!(a.contains(&4)); - /// assert!(a.contains(&5)); - /// ``` - #[stable(feature = "btree_append", since = "1.11.0")] - pub fn append(&mut self, other: &mut Self) { - self.map.append(&mut other.map); - } - - /// Splits the collection into two at the given key. Returns everything after the given key, - /// including the key. - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut a = BTreeSet::new(); - /// a.insert(1); - /// a.insert(2); - /// a.insert(3); - /// a.insert(17); - /// a.insert(41); - /// - /// let b = a.split_off(&3); - /// - /// assert_eq!(a.len(), 2); - /// assert_eq!(b.len(), 3); - /// - /// assert!(a.contains(&1)); - /// assert!(a.contains(&2)); - /// - /// assert!(b.contains(&3)); - /// assert!(b.contains(&17)); - /// assert!(b.contains(&41)); - /// ``` - #[stable(feature = "btree_split_off", since = "1.11.0")] - pub fn split_off<Q: ?Sized + Ord>(&mut self, key: &Q) -> Self - where - T: Borrow<Q>, - { - BTreeSet { map: self.map.split_off(key) } - } - - /// Creates an iterator which uses a closure to determine if a value should be removed. - /// - /// If the closure returns true, then the value is removed and yielded. - /// If the closure returns false, the value will remain in the list and will not be yielded - /// by the iterator. - /// - /// If the iterator is only partially consumed or not consumed at all, each of the remaining - /// values will still be subjected to the closure and removed and dropped if it returns true. - /// - /// It is unspecified how many more values will be subjected to the closure - /// if a panic occurs in the closure, or if a panic occurs while dropping a value, or if the - /// `DrainFilter` itself is leaked. - /// - /// # Examples - /// - /// Splitting a set into even and odd values, reusing the original set: - /// - /// ``` - /// #![feature(btree_drain_filter)] - /// use std::collections::BTreeSet; - /// - /// let mut set: BTreeSet<i32> = (0..8).collect(); - /// let evens: BTreeSet<_> = set.drain_filter(|v| v % 2 == 0).collect(); - /// let odds = set; - /// assert_eq!(evens.into_iter().collect::<Vec<_>>(), vec![0, 2, 4, 6]); - /// assert_eq!(odds.into_iter().collect::<Vec<_>>(), vec![1, 3, 5, 7]); - /// ``` - #[unstable(feature = "btree_drain_filter", issue = "70530")] - pub fn drain_filter<'a, F>(&'a mut self, pred: F) -> DrainFilter<'a, T, F> - where - F: 'a + FnMut(&T) -> bool, - { - DrainFilter { pred, inner: self.map.drain_filter_inner() } - } -} - -impl<T> BTreeSet<T> { - /// Gets an iterator that visits the values in the `BTreeSet` in ascending order. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let set: BTreeSet<usize> = [1, 2, 3].iter().cloned().collect(); - /// let mut set_iter = set.iter(); - /// assert_eq!(set_iter.next(), Some(&1)); - /// assert_eq!(set_iter.next(), Some(&2)); - /// assert_eq!(set_iter.next(), Some(&3)); - /// assert_eq!(set_iter.next(), None); - /// ``` - /// - /// Values returned by the iterator are returned in ascending order: - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let set: BTreeSet<usize> = [3, 1, 2].iter().cloned().collect(); - /// let mut set_iter = set.iter(); - /// assert_eq!(set_iter.next(), Some(&1)); - /// assert_eq!(set_iter.next(), Some(&2)); - /// assert_eq!(set_iter.next(), Some(&3)); - /// assert_eq!(set_iter.next(), None); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn iter(&self) -> Iter<'_, T> { - Iter { iter: self.map.keys() } - } - - /// Returns the number of elements in the set. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut v = BTreeSet::new(); - /// assert_eq!(v.len(), 0); - /// v.insert(1); - /// assert_eq!(v.len(), 1); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn len(&self) -> usize { - self.map.len() - } - - /// Returns `true` if the set contains no elements. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let mut v = BTreeSet::new(); - /// assert!(v.is_empty()); - /// v.insert(1); - /// assert!(!v.is_empty()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_empty(&self) -> bool { - self.len() == 0 - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Ord> FromIterator<T> for BTreeSet<T> { - fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> BTreeSet<T> { - let mut set = BTreeSet::new(); - set.extend(iter); - set - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> IntoIterator for BTreeSet<T> { - type Item = T; - type IntoIter = IntoIter<T>; - - /// Gets an iterator for moving out the `BTreeSet`'s contents. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let set: BTreeSet<usize> = [1, 2, 3, 4].iter().cloned().collect(); - /// - /// let v: Vec<_> = set.into_iter().collect(); - /// assert_eq!(v, [1, 2, 3, 4]); - /// ``` - fn into_iter(self) -> IntoIter<T> { - IntoIter { iter: self.map.into_iter() } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T> IntoIterator for &'a BTreeSet<T> { - type Item = &'a T; - type IntoIter = Iter<'a, T>; - - fn into_iter(self) -> Iter<'a, T> { - self.iter() - } -} - -/// An iterator produced by calling `drain_filter` on BTreeSet. -#[unstable(feature = "btree_drain_filter", issue = "70530")] -pub struct DrainFilter<'a, T, F> -where - T: 'a, - F: 'a + FnMut(&T) -> bool, -{ - pred: F, - inner: super::map::DrainFilterInner<'a, T, ()>, -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<T, F> Drop for DrainFilter<'_, T, F> -where - F: FnMut(&T) -> bool, -{ - fn drop(&mut self) { - self.for_each(drop); - } -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<T, F> fmt::Debug for DrainFilter<'_, T, F> -where - T: fmt::Debug, - F: FnMut(&T) -> bool, -{ - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_tuple("DrainFilter").field(&self.inner.peek().map(|(k, _)| k)).finish() - } -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<'a, T, F> Iterator for DrainFilter<'_, T, F> -where - F: 'a + FnMut(&T) -> bool, -{ - type Item = T; - - fn next(&mut self) -> Option<T> { - let pred = &mut self.pred; - let mut mapped_pred = |k: &T, _v: &mut ()| pred(k); - self.inner.next(&mut mapped_pred).map(|(k, _)| k) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} - -#[unstable(feature = "btree_drain_filter", issue = "70530")] -impl<T, F> FusedIterator for DrainFilter<'_, T, F> where F: FnMut(&T) -> bool {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Ord> Extend<T> for BTreeSet<T> { - #[inline] - fn extend<Iter: IntoIterator<Item = T>>(&mut self, iter: Iter) { - iter.into_iter().for_each(move |elem| { - self.insert(elem); - }); - } - - #[inline] - fn extend_one(&mut self, elem: T) { - self.insert(elem); - } -} - -#[stable(feature = "extend_ref", since = "1.2.0")] -impl<'a, T: 'a + Ord + Copy> Extend<&'a T> for BTreeSet<T> { - fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { - self.extend(iter.into_iter().cloned()); - } - - #[inline] - fn extend_one(&mut self, &elem: &'a T) { - self.insert(elem); - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Ord> Default for BTreeSet<T> { - /// Makes an empty `BTreeSet<T>` with a reasonable choice of B. - fn default() -> BTreeSet<T> { - BTreeSet::new() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Ord + Clone> Sub<&BTreeSet<T>> for &BTreeSet<T> { - type Output = BTreeSet<T>; - - /// Returns the difference of `self` and `rhs` as a new `BTreeSet<T>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: BTreeSet<_> = vec![3, 4, 5].into_iter().collect(); - /// - /// let result = &a - &b; - /// let result_vec: Vec<_> = result.into_iter().collect(); - /// assert_eq!(result_vec, [1, 2]); - /// ``` - fn sub(self, rhs: &BTreeSet<T>) -> BTreeSet<T> { - self.difference(rhs).cloned().collect() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Ord + Clone> BitXor<&BTreeSet<T>> for &BTreeSet<T> { - type Output = BTreeSet<T>; - - /// Returns the symmetric difference of `self` and `rhs` as a new `BTreeSet<T>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: BTreeSet<_> = vec![2, 3, 4].into_iter().collect(); - /// - /// let result = &a ^ &b; - /// let result_vec: Vec<_> = result.into_iter().collect(); - /// assert_eq!(result_vec, [1, 4]); - /// ``` - fn bitxor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> { - self.symmetric_difference(rhs).cloned().collect() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Ord + Clone> BitAnd<&BTreeSet<T>> for &BTreeSet<T> { - type Output = BTreeSet<T>; - - /// Returns the intersection of `self` and `rhs` as a new `BTreeSet<T>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: BTreeSet<_> = vec![2, 3, 4].into_iter().collect(); - /// - /// let result = &a & &b; - /// let result_vec: Vec<_> = result.into_iter().collect(); - /// assert_eq!(result_vec, [2, 3]); - /// ``` - fn bitand(self, rhs: &BTreeSet<T>) -> BTreeSet<T> { - self.intersection(rhs).cloned().collect() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Ord + Clone> BitOr<&BTreeSet<T>> for &BTreeSet<T> { - type Output = BTreeSet<T>; - - /// Returns the union of `self` and `rhs` as a new `BTreeSet<T>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::BTreeSet; - /// - /// let a: BTreeSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: BTreeSet<_> = vec![3, 4, 5].into_iter().collect(); - /// - /// let result = &a | &b; - /// let result_vec: Vec<_> = result.into_iter().collect(); - /// assert_eq!(result_vec, [1, 2, 3, 4, 5]); - /// ``` - fn bitor(self, rhs: &BTreeSet<T>) -> BTreeSet<T> { - self.union(rhs).cloned().collect() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T: Debug> Debug for BTreeSet<T> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - f.debug_set().entries(self.iter()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> Clone for Iter<'_, T> { - fn clone(&self) -> Self { - Iter { iter: self.iter.clone() } - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T> Iterator for Iter<'a, T> { - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - self.iter.next() - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } - - fn last(mut self) -> Option<&'a T> { - self.next_back() - } - - fn min(mut self) -> Option<&'a T> { - self.next() - } - - fn max(mut self) -> Option<&'a T> { - self.next_back() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T> DoubleEndedIterator for Iter<'a, T> { - fn next_back(&mut self) -> Option<&'a T> { - self.iter.next_back() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> ExactSizeIterator for Iter<'_, T> { - fn len(&self) -> usize { - self.iter.len() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<T> FusedIterator for Iter<'_, T> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> Iterator for IntoIter<T> { - type Item = T; - - fn next(&mut self) -> Option<T> { - self.iter.next().map(|(k, _)| k) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> DoubleEndedIterator for IntoIter<T> { - fn next_back(&mut self) -> Option<T> { - self.iter.next_back().map(|(k, _)| k) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> ExactSizeIterator for IntoIter<T> { - fn len(&self) -> usize { - self.iter.len() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<T> FusedIterator for IntoIter<T> {} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<T> Clone for Range<'_, T> { - fn clone(&self) -> Self { - Range { iter: self.iter.clone() } - } -} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<'a, T> Iterator for Range<'a, T> { - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - self.iter.next().map(|(k, _)| k) - } - - fn last(mut self) -> Option<&'a T> { - self.next_back() - } - - fn min(mut self) -> Option<&'a T> { - self.next() - } - - fn max(mut self) -> Option<&'a T> { - self.next_back() - } -} - -#[stable(feature = "btree_range", since = "1.17.0")] -impl<'a, T> DoubleEndedIterator for Range<'a, T> { - fn next_back(&mut self) -> Option<&'a T> { - self.iter.next_back().map(|(k, _)| k) - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<T> FusedIterator for Range<'_, T> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> Clone for Difference<'_, T> { - fn clone(&self) -> Self { - Difference { - inner: match &self.inner { - DifferenceInner::Stitch { self_iter, other_iter } => DifferenceInner::Stitch { - self_iter: self_iter.clone(), - other_iter: other_iter.clone(), - }, - DifferenceInner::Search { self_iter, other_set } => { - DifferenceInner::Search { self_iter: self_iter.clone(), other_set } - } - DifferenceInner::Iterate(iter) => DifferenceInner::Iterate(iter.clone()), - }, - } - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T: Ord> Iterator for Difference<'a, T> { - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - match &mut self.inner { - DifferenceInner::Stitch { self_iter, other_iter } => { - let mut self_next = self_iter.next()?; - loop { - match other_iter.peek().map_or(Less, |other_next| self_next.cmp(other_next)) { - Less => return Some(self_next), - Equal => { - self_next = self_iter.next()?; - other_iter.next(); - } - Greater => { - other_iter.next(); - } - } - } - } - DifferenceInner::Search { self_iter, other_set } => loop { - let self_next = self_iter.next()?; - if !other_set.contains(&self_next) { - return Some(self_next); - } - }, - DifferenceInner::Iterate(iter) => iter.next(), - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - let (self_len, other_len) = match &self.inner { - DifferenceInner::Stitch { self_iter, other_iter } => { - (self_iter.len(), other_iter.len()) - } - DifferenceInner::Search { self_iter, other_set } => (self_iter.len(), other_set.len()), - DifferenceInner::Iterate(iter) => (iter.len(), 0), - }; - (self_len.saturating_sub(other_len), Some(self_len)) - } - - fn min(mut self) -> Option<&'a T> { - self.next() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<T: Ord> FusedIterator for Difference<'_, T> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> Clone for SymmetricDifference<'_, T> { - fn clone(&self) -> Self { - SymmetricDifference(self.0.clone()) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T: Ord> Iterator for SymmetricDifference<'a, T> { - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - loop { - let (a_next, b_next) = self.0.nexts(); - if a_next.and(b_next).is_none() { - return a_next.or(b_next); - } - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - let (a_len, b_len) = self.0.lens(); - // No checked_add, because even if a and b refer to the same set, - // and T is an empty type, the storage overhead of sets limits - // the number of elements to less than half the range of usize. - (0, Some(a_len + b_len)) - } - - fn min(mut self) -> Option<&'a T> { - self.next() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<T: Ord> FusedIterator for SymmetricDifference<'_, T> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> Clone for Intersection<'_, T> { - fn clone(&self) -> Self { - Intersection { - inner: match &self.inner { - IntersectionInner::Stitch { a, b } => { - IntersectionInner::Stitch { a: a.clone(), b: b.clone() } - } - IntersectionInner::Search { small_iter, large_set } => { - IntersectionInner::Search { small_iter: small_iter.clone(), large_set } - } - IntersectionInner::Answer(answer) => IntersectionInner::Answer(*answer), - }, - } - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T: Ord> Iterator for Intersection<'a, T> { - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - match &mut self.inner { - IntersectionInner::Stitch { a, b } => { - let mut a_next = a.next()?; - let mut b_next = b.next()?; - loop { - match a_next.cmp(b_next) { - Less => a_next = a.next()?, - Greater => b_next = b.next()?, - Equal => return Some(a_next), - } - } - } - IntersectionInner::Search { small_iter, large_set } => loop { - let small_next = small_iter.next()?; - if large_set.contains(&small_next) { - return Some(small_next); - } - }, - IntersectionInner::Answer(answer) => answer.take(), - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - match &self.inner { - IntersectionInner::Stitch { a, b } => (0, Some(min(a.len(), b.len()))), - IntersectionInner::Search { small_iter, .. } => (0, Some(small_iter.len())), - IntersectionInner::Answer(None) => (0, Some(0)), - IntersectionInner::Answer(Some(_)) => (1, Some(1)), - } - } - - fn min(mut self) -> Option<&'a T> { - self.next() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<T: Ord> FusedIterator for Intersection<'_, T> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T> Clone for Union<'_, T> { - fn clone(&self) -> Self { - Union(self.0.clone()) - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T: Ord> Iterator for Union<'a, T> { - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - let (a_next, b_next) = self.0.nexts(); - a_next.or(b_next) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - let (a_len, b_len) = self.0.lens(); - // No checked_add - see SymmetricDifference::size_hint. - (max(a_len, b_len), Some(a_len + b_len)) - } - - fn min(mut self) -> Option<&'a T> { - self.next() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<T: Ord> FusedIterator for Union<'_, T> {} |