--- /dev/null
+ Apache License
+ Version 2.0, January 2004
+ http://www.apache.org/licenses/
+
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--- /dev/null
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A `HashMap` wrapper that holds key-value pairs in insertion order.
+//!
+//! # Examples
+//!
+//! ```
+//! use linked_hash_map::LinkedHashMap;
+//!
+//! let mut map = LinkedHashMap::new();
+//! map.insert(2, 20);
+//! map.insert(1, 10);
+//! map.insert(3, 30);
+//! assert_eq!(map[&1], 10);
+//! assert_eq!(map[&2], 20);
+//! assert_eq!(map[&3], 30);
+//!
+//! let items: Vec<(i32, i32)> = map.iter().map(|t| (*t.0, *t.1)).collect();
+//! assert_eq!(items, [(2, 20), (1, 10), (3, 30)]);
+//! ```
+
+#![forbid(missing_docs)]
+#![cfg_attr(all(feature = "nightly", test), feature(test))]
+
+// Optional Serde support
+#[cfg(feature = "serde_impl")]
+pub mod serde;
+// Optional Heapsize support
+#[cfg(feature = "heapsize_impl")]
+mod heapsize;
+#[cfg(test)]
+mod tests;
+
+use std::borrow::Borrow;
+use std::cmp::Ordering;
+use std::collections::hash_map::{self, HashMap};
+use std::fmt;
+use std::hash::{BuildHasher, Hash, Hasher};
+use std::iter;
+use std::marker;
+use std::mem;
+use std::ops::{Index, IndexMut};
+use std::ptr::{self, addr_of_mut};
+
+struct KeyRef<K> {
+ k: *const K,
+}
+
+struct Node<K, V> {
+ next: *mut Node<K, V>,
+ prev: *mut Node<K, V>,
+ key: K,
+ value: V,
+}
+
+/// A linked hash map.
+pub struct LinkedHashMap<K, V, S = hash_map::RandomState> {
+ map: HashMap<KeyRef<K>, *mut Node<K, V>, S>,
+ head: *mut Node<K, V>,
+ free: *mut Node<K, V>,
+}
+
+impl<K: Hash> Hash for KeyRef<K> {
+ fn hash<H: Hasher>(&self, state: &mut H) {
+ unsafe { (*self.k).hash(state) }
+ }
+}
+
+impl<K: PartialEq> PartialEq for KeyRef<K> {
+ fn eq(&self, other: &Self) -> bool {
+ unsafe { (*self.k).eq(&*other.k) }
+ }
+}
+
+impl<K: Eq> Eq for KeyRef<K> {}
+
+// This type exists only to support borrowing `KeyRef`s, which cannot be borrowed to `Q` directly
+// due to conflicting implementations of `Borrow`. The layout of `&Qey<Q>` must be identical to
+// `&Q` in order to support transmuting in the `Qey::from_ref` method.
+#[derive(Hash, PartialEq, Eq)]
+#[repr(transparent)]
+struct Qey<Q: ?Sized>(Q);
+
+impl<Q: ?Sized> Qey<Q> {
+ fn from_ref(q: &Q) -> &Self {
+ unsafe { mem::transmute(q) }
+ }
+}
+
+impl<K, Q: ?Sized> Borrow<Qey<Q>> for KeyRef<K>
+where
+ K: Borrow<Q>,
+{
+ fn borrow(&self) -> &Qey<Q> {
+ Qey::from_ref(unsafe { (*self.k).borrow() })
+ }
+}
+
+impl<K, V> Node<K, V> {
+ fn new(k: K, v: V) -> Self {
+ Node {
+ key: k,
+ value: v,
+ next: ptr::null_mut(),
+ prev: ptr::null_mut(),
+ }
+ }
+}
+
+// drop empty node without dropping its key and value
+unsafe fn drop_empty_node<K, V>(the_box: *mut Node<K, V>) {
+ // Safety:
+ // In this crate all `Node` is allocated via `Box` or `alloc`, and `Box` uses the
+ // Global allocator for its allocation,
+ // (https://doc.rust-lang.org/std/boxed/index.html#memory-layout) so we can safely
+ // deallocate the pointer to `Node` by calling `dealloc` method
+ let layout = std::alloc::Layout::new::<Node<K, V>>();
+ std::alloc::dealloc(the_box as *mut u8, layout);
+}
+
+impl<K: Hash + Eq, V> LinkedHashMap<K, V> {
+ /// Creates a linked hash map.
+ pub fn new() -> Self {
+ Self::with_map(HashMap::new())
+ }
+
+ /// Creates an empty linked hash map with the given initial capacity.
+ pub fn with_capacity(capacity: usize) -> Self {
+ Self::with_map(HashMap::with_capacity(capacity))
+ }
+}
+
+impl<K, V, S> LinkedHashMap<K, V, S> {
+ #[inline]
+ fn detach(&mut self, node: *mut Node<K, V>) {
+ unsafe {
+ (*(*node).prev).next = (*node).next;
+ (*(*node).next).prev = (*node).prev;
+ }
+ }
+
+ #[inline]
+ fn attach(&mut self, node: *mut Node<K, V>) {
+ unsafe {
+ (*node).next = (*self.head).next;
+ (*node).prev = self.head;
+ (*self.head).next = node;
+ (*(*node).next).prev = node;
+ }
+ }
+
+ // Caller must check `!self.head.is_null()`
+ unsafe fn drop_entries(&mut self) {
+ let mut cur = (*self.head).next;
+ while cur != self.head {
+ let next = (*cur).next;
+ Box::from_raw(cur);
+ cur = next;
+ }
+ }
+
+ fn clear_free_list(&mut self) {
+ unsafe {
+ let mut free = self.free;
+ while !free.is_null() {
+ let next_free = (*free).next;
+ drop_empty_node(free);
+ free = next_free;
+ }
+ self.free = ptr::null_mut();
+ }
+ }
+
+ fn ensure_guard_node(&mut self) {
+ if self.head.is_null() {
+ // allocate the guard node if not present
+ unsafe {
+ let node_layout = std::alloc::Layout::new::<Node<K, V>>();
+ self.head = std::alloc::alloc(node_layout) as *mut Node<K, V>;
+ (*self.head).next = self.head;
+ (*self.head).prev = self.head;
+ }
+ }
+ }
+}
+
+impl<K: Hash + Eq, V, S: BuildHasher> LinkedHashMap<K, V, S> {
+ fn with_map(map: HashMap<KeyRef<K>, *mut Node<K, V>, S>) -> Self {
+ LinkedHashMap {
+ map,
+ head: ptr::null_mut(),
+ free: ptr::null_mut(),
+ }
+ }
+
+ /// Creates an empty linked hash map with the given initial hash builder.
+ pub fn with_hasher(hash_builder: S) -> Self {
+ Self::with_map(HashMap::with_hasher(hash_builder))
+ }
+
+ /// Creates an empty linked hash map with the given initial capacity and hash builder.
+ pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> Self {
+ Self::with_map(HashMap::with_capacity_and_hasher(capacity, hash_builder))
+ }
+
+ /// Reserves capacity for at least `additional` more elements to be inserted into the map. The
+ /// map may reserve more space to avoid frequent allocations.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new allocation size overflows `usize.`
+ pub fn reserve(&mut self, additional: usize) {
+ self.map.reserve(additional);
+ }
+
+ /// Shrinks the capacity of the map as much as possible. It will drop down as much as possible
+ /// while maintaining the internal rules and possibly leaving some space in accordance with the
+ /// resize policy.
+ pub fn shrink_to_fit(&mut self) {
+ self.map.shrink_to_fit();
+ self.clear_free_list();
+ }
+
+ /// Gets the given key's corresponding entry in the map for in-place manipulation.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut letters = LinkedHashMap::new();
+ ///
+ /// for ch in "a short treatise on fungi".chars() {
+ /// let counter = letters.entry(ch).or_insert(0);
+ /// *counter += 1;
+ /// }
+ ///
+ /// assert_eq!(letters[&'s'], 2);
+ /// assert_eq!(letters[&'t'], 3);
+ /// assert_eq!(letters[&'u'], 1);
+ /// assert_eq!(letters.get(&'y'), None);
+ /// ```
+ pub fn entry(&mut self, k: K) -> Entry<K, V, S> {
+ let self_ptr: *mut Self = self;
+
+ if let Some(entry) = self.map.get_mut(&KeyRef { k: &k }) {
+ return Entry::Occupied(OccupiedEntry {
+ entry: *entry,
+ map: self_ptr,
+ marker: marker::PhantomData,
+ });
+ }
+
+ Entry::Vacant(VacantEntry { key: k, map: self })
+ }
+
+ /// Returns an iterator visiting all entries in insertion order.
+ /// Iterator element type is `OccupiedEntry<K, V, S>`. Allows for removal
+ /// as well as replacing the entry.
+ ///
+ /// # Examples
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert("a", 10);
+ /// map.insert("c", 30);
+ /// map.insert("b", 20);
+ ///
+ /// {
+ /// let mut iter = map.entries();
+ /// let mut entry = iter.next().unwrap();
+ /// assert_eq!(&"a", entry.key());
+ /// *entry.get_mut() = 17;
+ /// }
+ ///
+ /// assert_eq!(&17, map.get(&"a").unwrap());
+ /// ```
+ pub fn entries(&mut self) -> Entries<K, V, S> {
+ let head = if !self.head.is_null() {
+ unsafe { (*self.head).prev }
+ } else {
+ ptr::null_mut()
+ };
+ Entries {
+ map: self,
+ head,
+ remaining: self.len(),
+ marker: marker::PhantomData,
+ }
+ }
+
+ /// Inserts a key-value pair into the map. If the key already existed, the old value is
+ /// returned.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ ///
+ /// map.insert(1, "a");
+ /// map.insert(2, "b");
+ /// assert_eq!(map[&1], "a");
+ /// assert_eq!(map[&2], "b");
+ /// ```
+ pub fn insert(&mut self, k: K, v: V) -> Option<V> {
+ self.ensure_guard_node();
+
+ let (node, old_val) = match self.map.get(&KeyRef { k: &k }) {
+ Some(node) => {
+ let old_val = unsafe { ptr::replace(&mut (**node).value, v) };
+ (*node, Some(old_val))
+ }
+ None => {
+ let node = if self.free.is_null() {
+ Box::into_raw(Box::new(Node::new(k, v)))
+ } else {
+ // use a recycled box
+ unsafe {
+ let free = self.free;
+ self.free = (*free).next;
+ ptr::write(free, Node::new(k, v));
+ free
+ }
+ };
+ (node, None)
+ }
+ };
+ match old_val {
+ Some(_) => {
+ // Existing node, just update LRU position
+ self.detach(node);
+ self.attach(node);
+ }
+ None => {
+ let keyref = unsafe { &(*node).key };
+ self.map.insert(KeyRef { k: keyref }, node);
+ self.attach(node);
+ }
+ }
+ old_val
+ }
+
+ /// Checks if the map contains the given key.
+ pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool
+ where
+ K: Borrow<Q>,
+ Q: Eq + Hash,
+ {
+ self.map.contains_key(Qey::from_ref(k))
+ }
+
+ /// Returns the value corresponding to the key in the map.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ ///
+ /// map.insert(1, "a");
+ /// map.insert(2, "b");
+ /// map.insert(2, "c");
+ /// map.insert(3, "d");
+ ///
+ /// assert_eq!(map.get(&1), Some(&"a"));
+ /// assert_eq!(map.get(&2), Some(&"c"));
+ /// ```
+ pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
+ where
+ K: Borrow<Q>,
+ Q: Eq + Hash,
+ {
+ self.map
+ .get(Qey::from_ref(k))
+ .map(|e| unsafe { &(**e).value })
+ }
+
+ /// Returns the mutable reference corresponding to the key in the map.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ ///
+ /// map.insert(1, "a");
+ /// map.insert(2, "b");
+ ///
+ /// *map.get_mut(&1).unwrap() = "c";
+ /// assert_eq!(map.get(&1), Some(&"c"));
+ /// ```
+ pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>
+ where
+ K: Borrow<Q>,
+ Q: Eq + Hash,
+ {
+ self.map
+ .get(Qey::from_ref(k))
+ .map(|e| unsafe { &mut (**e).value })
+ }
+
+ /// Returns the value corresponding to the key in the map.
+ ///
+ /// If value is found, it is moved to the end of the list.
+ /// This operation can be used in implemenation of LRU cache.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ ///
+ /// map.insert(1, "a");
+ /// map.insert(2, "b");
+ /// map.insert(3, "d");
+ ///
+ /// assert_eq!(map.get_refresh(&2), Some(&mut "b"));
+ ///
+ /// assert_eq!((&2, &"b"), map.iter().rev().next().unwrap());
+ /// ```
+ pub fn get_refresh<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>
+ where
+ K: Borrow<Q>,
+ Q: Eq + Hash,
+ {
+ let (value, node_ptr_opt) = match self.map.get(Qey::from_ref(k)) {
+ None => (None, None),
+ Some(node) => (Some(unsafe { &mut (**node).value }), Some(*node)),
+ };
+ if let Some(node_ptr) = node_ptr_opt {
+ self.detach(node_ptr);
+ self.attach(node_ptr);
+ }
+ value
+ }
+
+ /// Removes and returns the value corresponding to the key from the map.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ ///
+ /// map.insert(2, "a");
+ ///
+ /// assert_eq!(map.remove(&1), None);
+ /// assert_eq!(map.remove(&2), Some("a"));
+ /// assert_eq!(map.remove(&2), None);
+ /// assert_eq!(map.len(), 0);
+ /// ```
+ pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
+ where
+ K: Borrow<Q>,
+ Q: Eq + Hash,
+ {
+ let removed = self.map.remove(Qey::from_ref(k));
+ removed.map(|node| {
+ self.detach(node);
+ unsafe {
+ // add to free list
+ (*node).next = self.free;
+ self.free = node;
+ // drop the key and return the value
+ drop(ptr::read(&(*node).key));
+ ptr::read(&(*node).value)
+ }
+ })
+ }
+
+ /// Returns the maximum number of key-value pairs the map can hold without reallocating.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map: LinkedHashMap<i32, &str> = LinkedHashMap::new();
+ /// let capacity = map.capacity();
+ /// ```
+ pub fn capacity(&self) -> usize {
+ self.map.capacity()
+ }
+
+ /// Removes the first entry.
+ ///
+ /// Can be used in implementation of LRU cache.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert(1, 10);
+ /// map.insert(2, 20);
+ /// map.pop_front();
+ /// assert_eq!(map.get(&1), None);
+ /// assert_eq!(map.get(&2), Some(&20));
+ /// ```
+ #[inline]
+ pub fn pop_front(&mut self) -> Option<(K, V)> {
+ if self.is_empty() {
+ return None;
+ }
+ let lru = unsafe { (*self.head).prev };
+ self.detach(lru);
+ self.map
+ .remove(&KeyRef {
+ k: unsafe { &(*lru).key },
+ })
+ .map(|e| {
+ let e = *unsafe { Box::from_raw(e) };
+ (e.key, e.value)
+ })
+ }
+
+ /// Gets the first entry.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert(1, 10);
+ /// map.insert(2, 20);
+ /// assert_eq!(map.front(), Some((&1, &10)));
+ /// ```
+ #[inline]
+ pub fn front(&self) -> Option<(&K, &V)> {
+ if self.is_empty() {
+ return None;
+ }
+ let lru = unsafe { (*self.head).prev };
+ self.map
+ .get(&KeyRef {
+ k: unsafe { &(*lru).key },
+ })
+ .map(|e| unsafe { (&(**e).key, &(**e).value) })
+ }
+
+ /// Removes the last entry.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert(1, 10);
+ /// map.insert(2, 20);
+ /// map.pop_back();
+ /// assert_eq!(map.get(&1), Some(&10));
+ /// assert_eq!(map.get(&2), None);
+ /// ```
+ #[inline]
+ pub fn pop_back(&mut self) -> Option<(K, V)> {
+ if self.is_empty() {
+ return None;
+ }
+ let mru = unsafe { (*self.head).next };
+ self.detach(mru);
+ self.map
+ .remove(&KeyRef {
+ k: unsafe { &(*mru).key },
+ })
+ .map(|e| {
+ let e = *unsafe { Box::from_raw(e) };
+ (e.key, e.value)
+ })
+ }
+
+ /// Gets the last entry.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert(1, 10);
+ /// map.insert(2, 20);
+ /// assert_eq!(map.back(), Some((&2, &20)));
+ /// ```
+ #[inline]
+ pub fn back(&self) -> Option<(&K, &V)> {
+ if self.is_empty() {
+ return None;
+ }
+ let mru = unsafe { (*self.head).next };
+ self.map
+ .get(&KeyRef {
+ k: unsafe { &(*mru).key },
+ })
+ .map(|e| unsafe { (&(**e).key, &(**e).value) })
+ }
+
+ /// Returns the number of key-value pairs in the map.
+ pub fn len(&self) -> usize {
+ self.map.len()
+ }
+
+ /// Returns whether the map is currently empty.
+ pub fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Returns a reference to the map's hasher.
+ pub fn hasher(&self) -> &S {
+ self.map.hasher()
+ }
+
+ /// Clears the map of all key-value pairs.
+ pub fn clear(&mut self) {
+ self.map.clear();
+ // update the guard node if present
+ if !self.head.is_null() {
+ unsafe {
+ self.drop_entries();
+ (*self.head).prev = self.head;
+ (*self.head).next = self.head;
+ }
+ }
+ }
+
+ /// Returns a double-ended iterator visiting all key-value pairs in order of insertion.
+ /// Iterator element type is `(&'a K, &'a V)`
+ ///
+ /// # Examples
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert("a", 10);
+ /// map.insert("c", 30);
+ /// map.insert("b", 20);
+ ///
+ /// let mut iter = map.iter();
+ /// assert_eq!((&"a", &10), iter.next().unwrap());
+ /// assert_eq!((&"c", &30), iter.next().unwrap());
+ /// assert_eq!((&"b", &20), iter.next().unwrap());
+ /// assert_eq!(None, iter.next());
+ /// ```
+ pub fn iter(&self) -> Iter<K, V> {
+ let head = if self.head.is_null() {
+ ptr::null_mut()
+ } else {
+ unsafe { (*self.head).prev }
+ };
+ Iter {
+ head,
+ tail: self.head,
+ remaining: self.len(),
+ marker: marker::PhantomData,
+ }
+ }
+
+ /// Returns a double-ended iterator visiting all key-value pairs in order of insertion.
+ /// Iterator element type is `(&'a K, &'a mut V)`
+ /// # Examples
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert("a", 10);
+ /// map.insert("c", 30);
+ /// map.insert("b", 20);
+ ///
+ /// {
+ /// let mut iter = map.iter_mut();
+ /// let mut entry = iter.next().unwrap();
+ /// assert_eq!(&"a", entry.0);
+ /// *entry.1 = 17;
+ /// }
+ ///
+ /// assert_eq!(&17, map.get(&"a").unwrap());
+ /// ```
+ pub fn iter_mut(&mut self) -> IterMut<K, V> {
+ let head = if self.head.is_null() {
+ ptr::null_mut()
+ } else {
+ unsafe { (*self.head).prev }
+ };
+ IterMut {
+ head,
+ tail: self.head,
+ remaining: self.len(),
+ marker: marker::PhantomData,
+ }
+ }
+
+ /// Clears the map, returning all key-value pairs as an iterator. Keeps the
+ /// allocated memory for reuse.
+ ///
+ /// If the returned iterator is dropped before being fully consumed, it
+ /// drops the remaining key-value pairs. The returned iterator keeps a
+ /// mutable borrow on the vector to optimize its implementation.
+ ///
+ /// Current performance implications (why to use this over into_iter()):
+ ///
+ /// * Clears the inner HashMap instead of dropping it
+ /// * Puts all drained nodes in the free-list instead of deallocating them
+ /// * Avoids deallocating the sentinel node
+ pub fn drain(&mut self) -> Drain<K, V> {
+ let len = self.len();
+ // Map should be empty now, regardless of current state
+ self.map.clear();
+ let (head, tail) = if len != 0 {
+ // This is basically the same as IntoIter's impl, but we don't
+ // deallocate/drop anything. Instead we make the sentinel head node
+ // point at itself (same state you get from removing the last element from a map),
+ // and then append the entire list to the free list. At this point all the entries
+ // have essentially been fed into mem::forget. The Drain iterator will then iterate
+ // over those nodes in the freelist (using `len` to know where to stop) and `read`
+ // the values out of the nodes, "unforgetting" them.
+ //
+ // This design results in no observable consequences for mem::forgetting the
+ // drain iterator, because the drain iterator has no responsibility to "fix up"
+ // things during iteration/destruction. That said, you will effectively mem::forget
+ // any elements that weren't yielded yet.
+ unsafe {
+ debug_assert!(!self.head.is_null());
+ debug_assert!(!(*self.head).prev.is_null());
+ debug_assert!((*self.head).prev != self.head);
+ let head = (*self.head).prev;
+ let tail = (*self.head).next;
+ (*self.head).prev = self.head;
+ (*self.head).next = self.head;
+ (*head).next = self.free;
+ (*tail).prev = ptr::null_mut();
+ self.free = tail;
+ (head, tail)
+ }
+ } else {
+ (ptr::null_mut(), ptr::null_mut())
+ };
+
+ Drain {
+ head,
+ tail,
+ remaining: len,
+ marker: marker::PhantomData,
+ }
+ }
+
+ /// Returns a double-ended iterator visiting all key in order of insertion.
+ ///
+ /// # Examples
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert('a', 10);
+ /// map.insert('c', 30);
+ /// map.insert('b', 20);
+ ///
+ /// let mut keys = map.keys();
+ /// assert_eq!(&'a', keys.next().unwrap());
+ /// assert_eq!(&'c', keys.next().unwrap());
+ /// assert_eq!(&'b', keys.next().unwrap());
+ /// assert_eq!(None, keys.next());
+ /// ```
+ pub fn keys(&self) -> Keys<K, V> {
+ Keys { inner: self.iter() }
+ }
+
+ /// Returns a double-ended iterator visiting all values in order of insertion.
+ ///
+ /// # Examples
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::new();
+ /// map.insert('a', 10);
+ /// map.insert('c', 30);
+ /// map.insert('b', 20);
+ ///
+ /// let mut values = map.values();
+ /// assert_eq!(&10, values.next().unwrap());
+ /// assert_eq!(&30, values.next().unwrap());
+ /// assert_eq!(&20, values.next().unwrap());
+ /// assert_eq!(None, values.next());
+ /// ```
+ pub fn values(&self) -> Values<K, V> {
+ Values { inner: self.iter() }
+ }
+}
+
+impl<'a, K, V, S, Q: ?Sized> Index<&'a Q> for LinkedHashMap<K, V, S>
+where
+ K: Hash + Eq + Borrow<Q>,
+ S: BuildHasher,
+ Q: Eq + Hash,
+{
+ type Output = V;
+
+ fn index(&self, index: &'a Q) -> &V {
+ self.get(index).expect("no entry found for key")
+ }
+}
+
+impl<'a, K, V, S, Q: ?Sized> IndexMut<&'a Q> for LinkedHashMap<K, V, S>
+where
+ K: Hash + Eq + Borrow<Q>,
+ S: BuildHasher,
+ Q: Eq + Hash,
+{
+ fn index_mut(&mut self, index: &'a Q) -> &mut V {
+ self.get_mut(index).expect("no entry found for key")
+ }
+}
+
+impl<K: Hash + Eq + Clone, V: Clone, S: BuildHasher + Clone> Clone for LinkedHashMap<K, V, S> {
+ fn clone(&self) -> Self {
+ let mut map = Self::with_hasher(self.map.hasher().clone());
+ map.extend(self.iter().map(|(k, v)| (k.clone(), v.clone())));
+ map
+ }
+}
+
+impl<K: Hash + Eq, V, S: BuildHasher + Default> Default for LinkedHashMap<K, V, S> {
+ fn default() -> Self {
+ Self::with_hasher(S::default())
+ }
+}
+
+impl<K: Hash + Eq, V, S: BuildHasher> Extend<(K, V)> for LinkedHashMap<K, V, S> {
+ fn extend<I: IntoIterator<Item = (K, V)>>(&mut self, iter: I) {
+ for (k, v) in iter {
+ self.insert(k, v);
+ }
+ }
+}
+
+impl<'a, K, V, S> Extend<(&'a K, &'a V)> for LinkedHashMap<K, V, S>
+where
+ K: 'a + Hash + Eq + Copy,
+ V: 'a + Copy,
+ S: BuildHasher,
+{
+ fn extend<I: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iter: I) {
+ for (&k, &v) in iter {
+ self.insert(k, v);
+ }
+ }
+}
+
+impl<K: Hash + Eq, V, S: BuildHasher + Default> iter::FromIterator<(K, V)>
+ for LinkedHashMap<K, V, S>
+{
+ fn from_iter<I: IntoIterator<Item = (K, V)>>(iter: I) -> Self {
+ let iter = iter.into_iter();
+ let mut map = Self::with_capacity_and_hasher(iter.size_hint().0, S::default());
+ map.extend(iter);
+ map
+ }
+}
+
+impl<A: fmt::Debug + Hash + Eq, B: fmt::Debug, S: BuildHasher> fmt::Debug
+ for LinkedHashMap<A, B, S>
+{
+ /// Returns a string that lists the key-value pairs in insertion order.
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.debug_map().entries(self).finish()
+ }
+}
+
+impl<K: Hash + Eq, V: PartialEq, S: BuildHasher> PartialEq for LinkedHashMap<K, V, S> {
+ fn eq(&self, other: &Self) -> bool {
+ self.len() == other.len() && self.iter().eq(other)
+ }
+}
+
+impl<K: Hash + Eq, V: Eq, S: BuildHasher> Eq for LinkedHashMap<K, V, S> {}
+
+impl<K: Hash + Eq + PartialOrd, V: PartialOrd, S: BuildHasher> PartialOrd
+ for LinkedHashMap<K, V, S>
+{
+ fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+ self.iter().partial_cmp(other)
+ }
+
+ fn lt(&self, other: &Self) -> bool {
+ self.iter().lt(other)
+ }
+
+ fn le(&self, other: &Self) -> bool {
+ self.iter().le(other)
+ }
+
+ fn ge(&self, other: &Self) -> bool {
+ self.iter().ge(other)
+ }
+
+ fn gt(&self, other: &Self) -> bool {
+ self.iter().gt(other)
+ }
+}
+
+impl<K: Hash + Eq + Ord, V: Ord, S: BuildHasher> Ord for LinkedHashMap<K, V, S> {
+ fn cmp(&self, other: &Self) -> Ordering {
+ self.iter().cmp(other)
+ }
+}
+
+impl<K: Hash + Eq, V: Hash, S: BuildHasher> Hash for LinkedHashMap<K, V, S> {
+ fn hash<H: Hasher>(&self, h: &mut H) {
+ for e in self.iter() {
+ e.hash(h);
+ }
+ }
+}
+
+unsafe impl<K: Send, V: Send, S: Send> Send for LinkedHashMap<K, V, S> {}
+
+unsafe impl<K: Sync, V: Sync, S: Sync> Sync for LinkedHashMap<K, V, S> {}
+
+impl<K, V, S> Drop for LinkedHashMap<K, V, S> {
+ fn drop(&mut self) {
+ if !self.head.is_null() {
+ unsafe {
+ self.drop_entries();
+ drop_empty_node(self.head);
+ }
+ }
+ self.clear_free_list();
+ }
+}
+
+/// An insertion-order iterator over a `LinkedHashMap`'s entries, with immutable references to the
+/// values.
+pub struct Iter<'a, K: 'a, V: 'a> {
+ head: *const Node<K, V>,
+ tail: *const Node<K, V>,
+ remaining: usize,
+ marker: marker::PhantomData<(&'a K, &'a V)>,
+}
+
+/// An insertion-order iterator over a `LinkedHashMap`'s entries, with mutable references to the
+/// values.
+pub struct IterMut<'a, K: 'a, V: 'a> {
+ head: *mut Node<K, V>,
+ tail: *mut Node<K, V>,
+ remaining: usize,
+ marker: marker::PhantomData<(&'a K, &'a mut V)>,
+}
+
+/// A consuming insertion-order iterator over a `LinkedHashMap`'s entries.
+pub struct IntoIter<K, V> {
+ head: *mut Node<K, V>,
+ tail: *mut Node<K, V>,
+ remaining: usize,
+ marker: marker::PhantomData<(K, V)>,
+}
+
+/// A draining insertion-order iterator over a `LinkedHashMap`'s entries.
+pub struct Drain<'a, K, V> {
+ head: *mut Node<K, V>,
+ tail: *mut Node<K, V>,
+ remaining: usize,
+ marker: marker::PhantomData<&'a mut (K, V)>,
+}
+
+/// An insertion-order iterator over a `LinkedHashMap`'s entries represented as
+/// an `OccupiedEntry`.
+pub struct Entries<'a, K: 'a, V: 'a, S: 'a = hash_map::RandomState> {
+ map: *mut LinkedHashMap<K, V, S>,
+ head: *mut Node<K, V>,
+ remaining: usize,
+ marker: marker::PhantomData<(&'a K, &'a mut V, &'a S)>,
+}
+
+unsafe impl<'a, K, V> Send for Iter<'a, K, V>
+where
+ K: Send,
+ V: Send,
+{
+}
+
+unsafe impl<'a, K, V> Send for IterMut<'a, K, V>
+where
+ K: Send,
+ V: Send,
+{
+}
+
+unsafe impl<'a, K, V> Send for Drain<'a, K, V>
+where
+ K: Send,
+ V: Send,
+{
+}
+
+unsafe impl<K, V> Send for IntoIter<K, V>
+where
+ K: Send,
+ V: Send,
+{
+}
+
+unsafe impl<'a, K, V, S> Send for Entries<'a, K, V, S>
+where
+ K: Send,
+ V: Send,
+ S: Send,
+{
+}
+
+unsafe impl<'a, K, V> Sync for Iter<'a, K, V>
+where
+ K: Sync,
+ V: Sync,
+{
+}
+
+unsafe impl<'a, K, V> Sync for IterMut<'a, K, V>
+where
+ K: Sync,
+ V: Sync,
+{
+}
+
+unsafe impl<'a, K, V> Sync for Drain<'a, K, V>
+where
+ K: Sync,
+ V: Sync,
+{
+}
+unsafe impl<K, V> Sync for IntoIter<K, V>
+where
+ K: Sync,
+ V: Sync,
+{
+}
+
+unsafe impl<'a, K, V, S> Sync for Entries<'a, K, V, S>
+where
+ K: Sync,
+ V: Sync,
+ S: Sync,
+{
+}
+
+impl<'a, K, V> Clone for Iter<'a, K, V> {
+ fn clone(&self) -> Self {
+ Iter { ..*self }
+ }
+}
+
+impl<K, V> Clone for IntoIter<K, V>
+where
+ K: Clone,
+ V: Clone,
+{
+ fn clone(&self) -> Self {
+ if self.remaining == 0 {
+ return IntoIter { ..*self };
+ }
+
+ fn clone_node<K, V>(e: *mut Node<K, V>) -> *mut Node<K, V>
+ where
+ K: Clone,
+ V: Clone,
+ {
+ Box::into_raw(Box::new(Node::new(unsafe { (*e).key.clone() }, unsafe {
+ (*e).value.clone()
+ })))
+ }
+
+ let mut cur = self.head;
+ let head = clone_node(cur);
+ let mut tail = head;
+ for _ in 1..self.remaining {
+ unsafe {
+ (*tail).prev = clone_node((*cur).prev);
+ (*(*tail).prev).next = tail;
+ tail = (*tail).prev;
+ cur = (*cur).prev;
+ }
+ }
+
+ IntoIter {
+ head,
+ tail,
+ remaining: self.remaining,
+ marker: marker::PhantomData,
+ }
+ }
+}
+
+impl<'a, K, V> Iterator for Iter<'a, K, V> {
+ type Item = (&'a K, &'a V);
+
+ fn next(&mut self) -> Option<(&'a K, &'a V)> {
+ if self.head == self.tail {
+ None
+ } else {
+ self.remaining -= 1;
+ unsafe {
+ let r = Some((&(*self.head).key, &(*self.head).value));
+ self.head = (*self.head).prev;
+ r
+ }
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (self.remaining, Some(self.remaining))
+ }
+}
+
+impl<'a, K, V> 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.head == self.tail {
+ None
+ } else {
+ self.remaining -= 1;
+ unsafe {
+ let r = Some((&(*self.head).key, &mut (*self.head).value));
+ self.head = (*self.head).prev;
+ r
+ }
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (self.remaining, Some(self.remaining))
+ }
+}
+
+impl<K, V> Iterator for IntoIter<K, V> {
+ type Item = (K, V);
+
+ fn next(&mut self) -> Option<(K, V)> {
+ if self.remaining == 0 {
+ return None;
+ }
+ self.remaining -= 1;
+ unsafe {
+ let prev = (*self.head).prev;
+ let e = *Box::from_raw(self.head);
+ self.head = prev;
+ Some((e.key, e.value))
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (self.remaining, Some(self.remaining))
+ }
+}
+
+impl<'a, K, V> Iterator for Drain<'a, K, V> {
+ type Item = (K, V);
+
+ fn next(&mut self) -> Option<(K, V)> {
+ if self.remaining == 0 {
+ return None;
+ }
+ self.remaining -= 1;
+ unsafe {
+ let prev = (*self.head).prev;
+ // Read the values out, the node is in the free-list already so these will
+ // be treated as uninit memory.
+ let k = addr_of_mut!((*self.head).key).read();
+ let v = addr_of_mut!((*self.head).value).read();
+ self.head = prev;
+ Some((k, v))
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (self.remaining, Some(self.remaining))
+ }
+}
+
+impl<'a, K, V> DoubleEndedIterator for Drain<'a, K, V> {
+ fn next_back(&mut self) -> Option<(K, V)> {
+ if self.remaining == 0 {
+ return None;
+ }
+ self.remaining -= 1;
+ unsafe {
+ let next = (*self.tail).next;
+ // Read the values out, the node is in the free-list already so these will
+ // be treated as uninit memory.
+ let k = addr_of_mut!((*self.tail).key).read();
+ let v = addr_of_mut!((*self.tail).value).read();
+ self.tail = next;
+ Some((k, v))
+ }
+ }
+}
+
+impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> {
+ fn len(&self) -> usize {
+ self.remaining
+ }
+}
+
+impl<'a, K, V, S: BuildHasher> Iterator for Entries<'a, K, V, S> {
+ type Item = OccupiedEntry<'a, K, V, S>;
+
+ fn next(&mut self) -> Option<OccupiedEntry<'a, K, V, S>> {
+ if self.remaining == 0 {
+ None
+ } else {
+ self.remaining -= 1;
+ unsafe {
+ let r = Some(OccupiedEntry {
+ map: self.map,
+ entry: self.head,
+ marker: marker::PhantomData,
+ });
+
+ self.head = (*self.head).prev;
+ r
+ }
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (self.remaining, Some(self.remaining))
+ }
+}
+
+impl<'a, K, V> DoubleEndedIterator for Iter<'a, K, V> {
+ fn next_back(&mut self) -> Option<(&'a K, &'a V)> {
+ if self.head == self.tail {
+ None
+ } else {
+ self.remaining -= 1;
+ unsafe {
+ self.tail = (*self.tail).next;
+ Some((&(*self.tail).key, &(*self.tail).value))
+ }
+ }
+ }
+}
+
+impl<'a, K, V> DoubleEndedIterator for IterMut<'a, K, V> {
+ fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> {
+ if self.head == self.tail {
+ None
+ } else {
+ self.remaining -= 1;
+ unsafe {
+ self.tail = (*self.tail).next;
+ Some((&(*self.tail).key, &mut (*self.tail).value))
+ }
+ }
+ }
+}
+
+impl<K, V> DoubleEndedIterator for IntoIter<K, V> {
+ fn next_back(&mut self) -> Option<(K, V)> {
+ if self.remaining == 0 {
+ return None;
+ }
+ self.remaining -= 1;
+ unsafe {
+ let next = (*self.tail).next;
+ let e = *Box::from_raw(self.tail);
+ self.tail = next;
+ Some((e.key, e.value))
+ }
+ }
+}
+
+impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
+ fn len(&self) -> usize {
+ self.remaining
+ }
+}
+
+impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> {
+ fn len(&self) -> usize {
+ self.remaining
+ }
+}
+
+impl<K, V> ExactSizeIterator for IntoIter<K, V> {
+ fn len(&self) -> usize {
+ self.remaining
+ }
+}
+
+impl<K, V> Drop for IntoIter<K, V> {
+ fn drop(&mut self) {
+ for _ in 0..self.remaining {
+ unsafe {
+ let next = (*self.tail).next;
+ Box::from_raw(self.tail);
+ self.tail = next;
+ }
+ }
+ }
+}
+
+impl<'a, K, V> Drop for Drain<'a, K, V> {
+ fn drop(&mut self) {
+ for _ in self {}
+ }
+}
+
+/// An insertion-order iterator over a `LinkedHashMap`'s keys.
+pub struct Keys<'a, K: 'a, V: 'a> {
+ inner: Iter<'a, K, V>,
+}
+
+impl<'a, K, V> Clone for Keys<'a, K, V> {
+ fn clone(&self) -> Self {
+ Keys {
+ inner: self.inner.clone(),
+ }
+ }
+}
+
+impl<'a, K, V> Iterator for Keys<'a, K, V> {
+ type Item = &'a K;
+
+ #[inline]
+ fn next(&mut self) -> Option<&'a K> {
+ self.inner.next().map(|e| e.0)
+ }
+ #[inline]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.inner.size_hint()
+ }
+}
+
+impl<'a, K, V> DoubleEndedIterator for Keys<'a, K, V> {
+ #[inline]
+ fn next_back(&mut self) -> Option<&'a K> {
+ self.inner.next_back().map(|e| e.0)
+ }
+}
+
+impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> {
+ fn len(&self) -> usize {
+ self.inner.len()
+ }
+}
+
+/// An insertion-order iterator over a `LinkedHashMap`'s values.
+pub struct Values<'a, K: 'a, V: 'a> {
+ inner: Iter<'a, K, V>,
+}
+
+impl<'a, K, V> Clone for Values<'a, K, V> {
+ fn clone(&self) -> Self {
+ Values {
+ inner: self.inner.clone(),
+ }
+ }
+}
+
+impl<'a, K, V> Iterator for Values<'a, K, V> {
+ type Item = &'a V;
+
+ #[inline]
+ fn next(&mut self) -> Option<&'a V> {
+ self.inner.next().map(|e| e.1)
+ }
+ #[inline]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.inner.size_hint()
+ }
+}
+
+impl<'a, K, V> DoubleEndedIterator for Values<'a, K, V> {
+ #[inline]
+ fn next_back(&mut self) -> Option<&'a V> {
+ self.inner.next_back().map(|e| e.1)
+ }
+}
+
+impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> {
+ fn len(&self) -> usize {
+ self.inner.len()
+ }
+}
+
+impl<'a, K: Hash + Eq, V, S: BuildHasher> IntoIterator for &'a LinkedHashMap<K, V, S> {
+ type Item = (&'a K, &'a V);
+ type IntoIter = Iter<'a, K, V>;
+ fn into_iter(self) -> Iter<'a, K, V> {
+ self.iter()
+ }
+}
+
+impl<'a, K: Hash + Eq, V, S: BuildHasher> IntoIterator for &'a mut LinkedHashMap<K, V, S> {
+ type Item = (&'a K, &'a mut V);
+ type IntoIter = IterMut<'a, K, V>;
+ fn into_iter(self) -> IterMut<'a, K, V> {
+ self.iter_mut()
+ }
+}
+
+impl<K: Hash + Eq, V, S: BuildHasher> IntoIterator for LinkedHashMap<K, V, S> {
+ type Item = (K, V);
+ type IntoIter = IntoIter<K, V>;
+ fn into_iter(mut self) -> IntoIter<K, V> {
+ let (head, tail) = if !self.head.is_null() {
+ unsafe { ((*self.head).prev, (*self.head).next) }
+ } else {
+ (ptr::null_mut(), ptr::null_mut())
+ };
+ let len = self.len();
+
+ if !self.head.is_null() {
+ unsafe { drop_empty_node(self.head) }
+ }
+ self.clear_free_list();
+ // drop the HashMap but not the LinkedHashMap
+ unsafe {
+ ptr::drop_in_place(&mut self.map);
+ }
+ mem::forget(self);
+
+ IntoIter {
+ head,
+ tail,
+ remaining: len,
+ marker: marker::PhantomData,
+ }
+ }
+}
+
+/// A view into a single location in a map, which may be vacant or occupied.
+pub enum Entry<'a, K: 'a, V: 'a, S: 'a = hash_map::RandomState> {
+ /// An occupied Entry.
+ Occupied(OccupiedEntry<'a, K, V, S>),
+ /// A vacant Entry.
+ Vacant(VacantEntry<'a, K, V, S>),
+}
+
+/// A view into a single occupied location in a `LinkedHashMap`.
+pub struct OccupiedEntry<'a, K: 'a, V: 'a, S: 'a = hash_map::RandomState> {
+ entry: *mut Node<K, V>,
+ map: *mut LinkedHashMap<K, V, S>,
+ marker: marker::PhantomData<&'a K>,
+}
+
+/// A view into a single empty location in a `LinkedHashMap`.
+pub struct VacantEntry<'a, K: 'a, V: 'a, S: 'a = hash_map::RandomState> {
+ key: K,
+ map: &'a mut LinkedHashMap<K, V, S>,
+}
+
+impl<'a, K: Hash + Eq, V, S: BuildHasher> Entry<'a, K, V, S> {
+ /// Returns the entry key
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::<String, u32>::new();
+ ///
+ /// assert_eq!("hello", map.entry("hello".to_string()).key());
+ /// ```
+ pub fn key(&self) -> &K {
+ match *self {
+ Entry::Occupied(ref e) => e.key(),
+ Entry::Vacant(ref e) => e.key(),
+ }
+ }
+
+ /// Ensures a value is in the entry by inserting the default if empty, and returns
+ /// a mutable reference to the value in the entry.
+ pub fn or_insert(self, default: V) -> &'a mut V {
+ match self {
+ Entry::Occupied(entry) => entry.into_mut(),
+ Entry::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.
+ pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
+ match self {
+ Entry::Occupied(entry) => entry.into_mut(),
+ Entry::Vacant(entry) => entry.insert(default()),
+ }
+ }
+
+ /// Provides in-place mutable access to an occupied entry before any
+ /// potential inserts into the map.
+ pub fn and_modify<F>(self, f: F) -> Self
+ where
+ F: FnOnce(&mut V),
+ {
+ match self {
+ Entry::Occupied(mut entry) => {
+ f(entry.get_mut());
+ Entry::Occupied(entry)
+ }
+ Entry::Vacant(entry) => Entry::Vacant(entry),
+ }
+ }
+
+ /// 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.
+ pub fn or_default(self) -> &'a mut V
+ where
+ V: Default,
+ {
+ match self {
+ Entry::Occupied(entry) => entry.into_mut(),
+ Entry::Vacant(entry) => entry.insert(V::default()),
+ }
+ }
+}
+
+impl<'a, K: Hash + Eq, V, S: BuildHasher> OccupiedEntry<'a, K, V, S> {
+ /// Gets a reference to the entry key
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::new();
+ ///
+ /// map.insert("foo".to_string(), 1);
+ /// assert_eq!("foo", map.entry("foo".to_string()).key());
+ /// ```
+ pub fn key(&self) -> &K {
+ unsafe { &(*self.entry).key }
+ }
+
+ /// Gets a reference to the value in the entry.
+ pub fn get(&self) -> &V {
+ unsafe { &(*self.entry).value }
+ }
+
+ /// Gets a mutable reference to the value in the entry.
+ pub fn get_mut(&mut self) -> &mut V {
+ unsafe { &mut (*self.entry).value }
+ }
+
+ /// Converts the OccupiedEntry into a mutable reference to the value in the entry
+ /// with a lifetime bound to the map itself
+ pub fn into_mut(self) -> &'a mut V {
+ unsafe { &mut (*self.entry).value }
+ }
+
+ /// Sets the value of the entry, and returns the entry's old value
+ pub fn insert(&mut self, value: V) -> V {
+ unsafe {
+ (*self.map).ensure_guard_node();
+
+ let old_val = mem::replace(&mut (*self.entry).value, value);
+ let node_ptr: *mut Node<K, V> = self.entry;
+
+ // Existing node, just update LRU position
+ (*self.map).detach(node_ptr);
+ (*self.map).attach(node_ptr);
+
+ old_val
+ }
+ }
+
+ /// Takes the value out of the entry, and returns it
+ pub fn remove(self) -> V {
+ unsafe { (*self.map).remove(&(*self.entry).key) }.unwrap()
+ }
+}
+
+impl<'a, K: 'a + Hash + Eq, V: 'a, S: BuildHasher> VacantEntry<'a, K, V, S> {
+ /// Gets a reference to the entry key
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use linked_hash_map::LinkedHashMap;
+ ///
+ /// let mut map = LinkedHashMap::<String, u32>::new();
+ ///
+ /// assert_eq!("foo", map.entry("foo".to_string()).key());
+ /// ```
+ pub fn key(&self) -> &K {
+ &self.key
+ }
+
+ /// Sets the value of the entry with the VacantEntry's key,
+ /// and returns a mutable reference to it
+ pub fn insert(self, value: V) -> &'a mut V {
+ self.map.ensure_guard_node();
+
+ let node = if self.map.free.is_null() {
+ Box::into_raw(Box::new(Node::new(self.key, value)))
+ } else {
+ // use a recycled box
+ unsafe {
+ let free = self.map.free;
+ self.map.free = (*free).next;
+ ptr::write(free, Node::new(self.key, value));
+ free
+ }
+ };
+
+ let keyref = unsafe { &(*node).key };
+
+ self.map.attach(node);
+
+ let ret = self.map.map.entry(KeyRef { k: keyref }).or_insert(node);
+ unsafe { &mut (**ret).value }
+ }
+}
projects / platform / upstream / rust-linked-hash-map.git / commitdiff