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Commit | Line | Data |
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9fa01778 | 1 | use core::borrow::Borrow; |
1a4d82fc | 2 | use core::cmp::Ordering; |
85aaf69f | 3 | use core::fmt::Debug; |
1a4d82fc | 4 | use core::hash::{Hash, Hasher}; |
dfeec247 | 5 | use core::iter::{FromIterator, FusedIterator, Peekable}; |
9cc50fc6 | 6 | use core::marker::PhantomData; |
ba9703b0 | 7 | use core::mem::{self, ManuallyDrop}; |
0531ce1d | 8 | use core::ops::Bound::{Excluded, Included, Unbounded}; |
9fa01778 | 9 | use core::ops::{Index, RangeBounds}; |
ba9703b0 | 10 | use core::{fmt, ptr}; |
1a4d82fc | 11 | |
dfeec247 | 12 | use super::node::{self, marker, ForceResult::*, Handle, InsertResult::*, NodeRef}; |
9fa01778 | 13 | use super::search::{self, SearchResult::*}; |
74b04a01 | 14 | use super::unwrap_unchecked; |
9cc50fc6 | 15 | |
9fa01778 | 16 | use Entry::*; |
dfeec247 | 17 | use UnderflowResult::*; |
1a4d82fc | 18 | |
1a4d82fc JJ |
19 | /// A map based on a B-Tree. |
20 | /// | |
21 | /// B-Trees represent a fundamental compromise between cache-efficiency and actually minimizing | |
22 | /// the amount of work performed in a search. In theory, a binary search tree (BST) is the optimal | |
23 | /// choice for a sorted map, as a perfectly balanced BST performs the theoretical minimum amount of | |
24 | /// comparisons necessary to find an element (log<sub>2</sub>n). However, in practice the way this | |
25 | /// is done is *very* inefficient for modern computer architectures. In particular, every element | |
26 | /// is stored in its own individually heap-allocated node. This means that every single insertion | |
27 | /// triggers a heap-allocation, and every single comparison should be a cache-miss. Since these | |
28 | /// are both notably expensive things to do in practice, we are forced to at very least reconsider | |
29 | /// the BST strategy. | |
30 | /// | |
31 | /// A B-Tree instead makes each node contain B-1 to 2B-1 elements in a contiguous array. By doing | |
32 | /// this, we reduce the number of allocations by a factor of B, and improve cache efficiency in | |
33 | /// searches. However, this does mean that searches will have to do *more* comparisons on average. | |
34 | /// The precise number of comparisons depends on the node search strategy used. For optimal cache | |
35 | /// efficiency, one could search the nodes linearly. For optimal comparisons, one could search | |
36 | /// the node using binary search. As a compromise, one could also perform a linear search | |
37 | /// that initially only checks every i<sup>th</sup> element for some choice of i. | |
38 | /// | |
39 | /// Currently, our implementation simply performs naive linear search. This provides excellent | |
40 | /// performance on *small* nodes of elements which are cheap to compare. However in the future we | |
41 | /// would like to further explore choosing the optimal search strategy based on the choice of B, | |
42 | /// and possibly other factors. Using linear search, searching for a random element is expected | |
ba9703b0 | 43 | /// to take O(B * log(n)) comparisons, which is generally worse than a BST. In practice, |
85aaf69f | 44 | /// however, performance is excellent. |
c34b1796 AL |
45 | /// |
46 | /// It is a logic error for a key to be modified in such a way that the key's ordering relative to | |
9e0c209e SL |
47 | /// any other key, as determined by the [`Ord`] trait, changes while it is in the map. This is |
48 | /// normally only possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code. | |
49 | /// | |
50 | /// [`Ord`]: ../../std/cmp/trait.Ord.html | |
51 | /// [`Cell`]: ../../std/cell/struct.Cell.html | |
52 | /// [`RefCell`]: ../../std/cell/struct.RefCell.html | |
54a0048b SL |
53 | /// |
54 | /// # Examples | |
55 | /// | |
56 | /// ``` | |
57 | /// use std::collections::BTreeMap; | |
58 | /// | |
59 | /// // type inference lets us omit an explicit type signature (which | |
60 | /// // would be `BTreeMap<&str, &str>` in this example). | |
61 | /// let mut movie_reviews = BTreeMap::new(); | |
62 | /// | |
3157f602 | 63 | /// // review some movies. |
54a0048b SL |
64 | /// movie_reviews.insert("Office Space", "Deals with real issues in the workplace."); |
65 | /// movie_reviews.insert("Pulp Fiction", "Masterpiece."); | |
66 | /// movie_reviews.insert("The Godfather", "Very enjoyable."); | |
0bf4aa26 | 67 | /// movie_reviews.insert("The Blues Brothers", "Eye lyked it a lot."); |
54a0048b SL |
68 | /// |
69 | /// // check for a specific one. | |
70 | /// if !movie_reviews.contains_key("Les Misérables") { | |
71 | /// println!("We've got {} reviews, but Les Misérables ain't one.", | |
72 | /// movie_reviews.len()); | |
73 | /// } | |
74 | /// | |
75 | /// // oops, this review has a lot of spelling mistakes, let's delete it. | |
76 | /// movie_reviews.remove("The Blues Brothers"); | |
77 | /// | |
78 | /// // look up the values associated with some keys. | |
79 | /// let to_find = ["Up!", "Office Space"]; | |
416331ca XL |
80 | /// for movie in &to_find { |
81 | /// match movie_reviews.get(movie) { | |
82 | /// Some(review) => println!("{}: {}", movie, review), | |
83 | /// None => println!("{} is unreviewed.", movie) | |
54a0048b SL |
84 | /// } |
85 | /// } | |
86 | /// | |
0731742a XL |
87 | /// // Look up the value for a key (will panic if the key is not found). |
88 | /// println!("Movie review: {}", movie_reviews["Office Space"]); | |
89 | /// | |
54a0048b SL |
90 | /// // iterate over everything. |
91 | /// for (movie, review) in &movie_reviews { | |
92 | /// println!("{}: \"{}\"", movie, review); | |
93 | /// } | |
94 | /// ``` | |
95 | /// | |
96 | /// `BTreeMap` also implements an [`Entry API`](#method.entry), which allows | |
97 | /// for more complex methods of getting, setting, updating and removing keys and | |
98 | /// their values: | |
99 | /// | |
100 | /// ``` | |
101 | /// use std::collections::BTreeMap; | |
102 | /// | |
103 | /// // type inference lets us omit an explicit type signature (which | |
104 | /// // would be `BTreeMap<&str, u8>` in this example). | |
105 | /// let mut player_stats = BTreeMap::new(); | |
106 | /// | |
107 | /// fn random_stat_buff() -> u8 { | |
108 | /// // could actually return some random value here - let's just return | |
109 | /// // some fixed value for now | |
110 | /// 42 | |
111 | /// } | |
112 | /// | |
113 | /// // insert a key only if it doesn't already exist | |
114 | /// player_stats.entry("health").or_insert(100); | |
115 | /// | |
116 | /// // insert a key using a function that provides a new value only if it | |
117 | /// // doesn't already exist | |
118 | /// player_stats.entry("defence").or_insert_with(random_stat_buff); | |
119 | /// | |
120 | /// // update a key, guarding against the key possibly not being set | |
121 | /// let stat = player_stats.entry("attack").or_insert(100); | |
122 | /// *stat += random_stat_buff(); | |
123 | /// ``` | |
85aaf69f | 124 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 125 | pub struct BTreeMap<K, V> { |
ba9703b0 | 126 | root: Option<node::Root<K, V>>, |
3157f602 | 127 | length: usize, |
9cc50fc6 SL |
128 | } |
129 | ||
c30ab7b3 | 130 | #[stable(feature = "btree_drop", since = "1.7.0")] |
32a655c1 | 131 | unsafe impl<#[may_dangle] K, #[may_dangle] V> Drop for BTreeMap<K, V> { |
9cc50fc6 SL |
132 | fn drop(&mut self) { |
133 | unsafe { | |
cc61c64b | 134 | drop(ptr::read(self).into_iter()); |
9cc50fc6 SL |
135 | } |
136 | } | |
137 | } | |
138 | ||
c30ab7b3 | 139 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
140 | impl<K: Clone, V: Clone> Clone for BTreeMap<K, V> { |
141 | fn clone(&self) -> BTreeMap<K, V> { | |
8faf50e0 | 142 | fn clone_subtree<'a, K: Clone, V: Clone>( |
dfeec247 | 143 | node: node::NodeRef<marker::Immut<'a>, K, V, marker::LeafOrInternal>, |
8faf50e0 | 144 | ) -> BTreeMap<K, V> |
dfeec247 XL |
145 | where |
146 | K: 'a, | |
147 | V: 'a, | |
8faf50e0 | 148 | { |
9cc50fc6 SL |
149 | match node.force() { |
150 | Leaf(leaf) => { | |
ba9703b0 | 151 | let mut out_tree = BTreeMap { root: Some(node::Root::new_leaf()), length: 0 }; |
9cc50fc6 SL |
152 | |
153 | { | |
ba9703b0 XL |
154 | let root = out_tree.root.as_mut().unwrap(); |
155 | let mut out_node = match root.as_mut().force() { | |
9cc50fc6 | 156 | Leaf(leaf) => leaf, |
3157f602 | 157 | Internal(_) => unreachable!(), |
9cc50fc6 SL |
158 | }; |
159 | ||
160 | let mut in_edge = leaf.first_edge(); | |
161 | while let Ok(kv) = in_edge.right_kv() { | |
162 | let (k, v) = kv.into_kv(); | |
163 | in_edge = kv.right_edge(); | |
164 | ||
165 | out_node.push(k.clone(), v.clone()); | |
166 | out_tree.length += 1; | |
167 | } | |
168 | } | |
169 | ||
170 | out_tree | |
3157f602 | 171 | } |
9cc50fc6 SL |
172 | Internal(internal) => { |
173 | let mut out_tree = clone_subtree(internal.first_edge().descend()); | |
ba9703b0 | 174 | out_tree.ensure_root_is_owned(); |
9cc50fc6 SL |
175 | |
176 | { | |
ba9703b0 XL |
177 | // Ideally we'd use the return of ensure_root_is_owned |
178 | // instead of re-unwrapping here but unfortunately that | |
179 | // borrows all of out_tree and we need access to the | |
180 | // length below. | |
181 | let mut out_node = out_tree.root.as_mut().unwrap().push_level(); | |
9cc50fc6 SL |
182 | let mut in_edge = internal.first_edge(); |
183 | while let Ok(kv) = in_edge.right_kv() { | |
184 | let (k, v) = kv.into_kv(); | |
185 | in_edge = kv.right_edge(); | |
186 | ||
187 | let k = (*k).clone(); | |
188 | let v = (*v).clone(); | |
189 | let subtree = clone_subtree(in_edge.descend()); | |
190 | ||
191 | // We can't destructure subtree directly | |
192 | // because BTreeMap implements Drop | |
193 | let (subroot, sublength) = unsafe { | |
ba9703b0 | 194 | let subtree = ManuallyDrop::new(subtree); |
9cc50fc6 SL |
195 | let root = ptr::read(&subtree.root); |
196 | let length = subtree.length; | |
9cc50fc6 SL |
197 | (root, length) |
198 | }; | |
199 | ||
ba9703b0 | 200 | out_node.push(k, v, subroot.unwrap_or_else(node::Root::new_leaf)); |
9cc50fc6 SL |
201 | out_tree.length += 1 + sublength; |
202 | } | |
203 | } | |
204 | ||
205 | out_tree | |
206 | } | |
207 | } | |
208 | } | |
209 | ||
416331ca | 210 | if self.is_empty() { |
8faf50e0 XL |
211 | // Ideally we'd call `BTreeMap::new` here, but that has the `K: |
212 | // Ord` constraint, which this method lacks. | |
ba9703b0 | 213 | BTreeMap { root: None, length: 0 } |
8faf50e0 | 214 | } else { |
ba9703b0 | 215 | clone_subtree(self.root.as_ref().unwrap().as_ref()) |
8faf50e0 | 216 | } |
9cc50fc6 | 217 | } |
74b04a01 XL |
218 | |
219 | fn clone_from(&mut self, other: &Self) { | |
220 | BTreeClone::clone_from(self, other); | |
221 | } | |
222 | } | |
223 | ||
224 | trait BTreeClone { | |
225 | fn clone_from(&mut self, other: &Self); | |
226 | } | |
227 | ||
228 | impl<K: Clone, V: Clone> BTreeClone for BTreeMap<K, V> { | |
229 | default fn clone_from(&mut self, other: &Self) { | |
230 | *self = other.clone(); | |
231 | } | |
232 | } | |
233 | ||
234 | impl<K: Clone + Ord, V: Clone> BTreeClone for BTreeMap<K, V> { | |
235 | fn clone_from(&mut self, other: &Self) { | |
236 | // This truncates `self` to `other.len()` by calling `split_off` on | |
237 | // the first key after `other.len()` elements if it exists. | |
238 | let split_off_key = if self.len() > other.len() { | |
239 | let diff = self.len() - other.len(); | |
240 | if diff <= other.len() { | |
241 | self.iter().nth_back(diff - 1).map(|pair| (*pair.0).clone()) | |
242 | } else { | |
243 | self.iter().nth(other.len()).map(|pair| (*pair.0).clone()) | |
244 | } | |
245 | } else { | |
246 | None | |
247 | }; | |
248 | if let Some(key) = split_off_key { | |
249 | self.split_off(&key); | |
250 | } | |
251 | ||
252 | let mut siter = self.range_mut(..); | |
253 | let mut oiter = other.iter(); | |
254 | // After truncation, `self` is at most as long as `other` so this loop | |
255 | // replaces every key-value pair in `self`. Since `oiter` is in sorted | |
256 | // order and the structure of the `BTreeMap` stays the same, | |
257 | // the BTree invariants are maintained at the end of the loop. | |
258 | while !siter.is_empty() { | |
259 | if let Some((ok, ov)) = oiter.next() { | |
260 | // SAFETY: This is safe because `siter` is nonempty. | |
261 | let (sk, sv) = unsafe { siter.next_unchecked() }; | |
262 | sk.clone_from(ok); | |
263 | sv.clone_from(ov); | |
264 | } else { | |
265 | break; | |
266 | } | |
267 | } | |
268 | // If `other` is longer than `self`, the remaining elements are inserted. | |
269 | self.extend(oiter.map(|(k, v)| ((*k).clone(), (*v).clone()))); | |
270 | } | |
1a4d82fc JJ |
271 | } |
272 | ||
9cc50fc6 | 273 | impl<K, Q: ?Sized> super::Recover<Q> for BTreeMap<K, ()> |
dfeec247 XL |
274 | where |
275 | K: Borrow<Q> + Ord, | |
276 | Q: Ord, | |
9cc50fc6 SL |
277 | { |
278 | type Key = K; | |
279 | ||
280 | fn get(&self, key: &Q) -> Option<&K> { | |
ba9703b0 | 281 | match search::search_tree(self.root.as_ref()?.as_ref(), key) { |
9cc50fc6 | 282 | Found(handle) => Some(handle.into_kv().0), |
3157f602 | 283 | GoDown(_) => None, |
9cc50fc6 SL |
284 | } |
285 | } | |
286 | ||
287 | fn take(&mut self, key: &Q) -> Option<K> { | |
ba9703b0 | 288 | match search::search_tree(self.root.as_mut()?.as_mut(), key) { |
dfeec247 XL |
289 | Found(handle) => Some( |
290 | OccupiedEntry { handle, length: &mut self.length, _marker: PhantomData } | |
291 | .remove_kv() | |
292 | .0, | |
293 | ), | |
3157f602 | 294 | GoDown(_) => None, |
9cc50fc6 SL |
295 | } |
296 | } | |
297 | ||
298 | fn replace(&mut self, key: K) -> Option<K> { | |
94b46f34 | 299 | self.ensure_root_is_owned(); |
ba9703b0 | 300 | match search::search_tree::<marker::Mut<'_>, K, (), K>(self.root.as_mut()?.as_mut(), &key) { |
9cc50fc6 SL |
301 | Found(handle) => Some(mem::replace(handle.into_kv_mut().0, key)), |
302 | GoDown(handle) => { | |
dfeec247 XL |
303 | VacantEntry { key, handle, length: &mut self.length, _marker: PhantomData } |
304 | .insert(()); | |
9cc50fc6 SL |
305 | None |
306 | } | |
307 | } | |
308 | } | |
1a4d82fc JJ |
309 | } |
310 | ||
cc61c64b XL |
311 | /// An iterator over the entries of a `BTreeMap`. |
312 | /// | |
313 | /// This `struct` is created by the [`iter`] method on [`BTreeMap`]. See its | |
314 | /// documentation for more. | |
315 | /// | |
316 | /// [`iter`]: struct.BTreeMap.html#method.iter | |
317 | /// [`BTreeMap`]: struct.BTreeMap.html | |
85aaf69f | 318 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 319 | pub struct Iter<'a, K: 'a, V: 'a> { |
9cc50fc6 | 320 | range: Range<'a, K, V>, |
3157f602 | 321 | length: usize, |
1a4d82fc JJ |
322 | } |
323 | ||
8bb4bdeb | 324 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
325 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Iter<'_, K, V> { |
326 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
8bb4bdeb XL |
327 | f.debug_list().entries(self.clone()).finish() |
328 | } | |
329 | } | |
330 | ||
cc61c64b XL |
331 | /// A mutable iterator over the entries of a `BTreeMap`. |
332 | /// | |
333 | /// This `struct` is created by the [`iter_mut`] method on [`BTreeMap`]. See its | |
334 | /// documentation for more. | |
335 | /// | |
336 | /// [`iter_mut`]: struct.BTreeMap.html#method.iter_mut | |
337 | /// [`BTreeMap`]: struct.BTreeMap.html | |
85aaf69f | 338 | #[stable(feature = "rust1", since = "1.0.0")] |
8bb4bdeb | 339 | #[derive(Debug)] |
1a4d82fc | 340 | pub struct IterMut<'a, K: 'a, V: 'a> { |
9cc50fc6 | 341 | range: RangeMut<'a, K, V>, |
3157f602 | 342 | length: usize, |
1a4d82fc JJ |
343 | } |
344 | ||
cc61c64b XL |
345 | /// An owning iterator over the entries of a `BTreeMap`. |
346 | /// | |
dfeec247 | 347 | /// This `struct` is created by the [`into_iter`] method on [`BTreeMap`] |
cc61c64b XL |
348 | /// (provided by the `IntoIterator` trait). See its documentation for more. |
349 | /// | |
350 | /// [`into_iter`]: struct.BTreeMap.html#method.into_iter | |
351 | /// [`BTreeMap`]: struct.BTreeMap.html | |
85aaf69f | 352 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 353 | pub struct IntoIter<K, V> { |
ba9703b0 XL |
354 | front: Option<Handle<NodeRef<marker::Owned, K, V, marker::Leaf>, marker::Edge>>, |
355 | back: Option<Handle<NodeRef<marker::Owned, K, V, marker::Leaf>, marker::Edge>>, | |
3157f602 | 356 | length: usize, |
1a4d82fc JJ |
357 | } |
358 | ||
8bb4bdeb XL |
359 | #[stable(feature = "collection_debug", since = "1.17.0")] |
360 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IntoIter<K, V> { | |
9fa01778 | 361 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
ba9703b0 XL |
362 | let range = Range { |
363 | front: self.front.as_ref().map(|f| f.reborrow()), | |
364 | back: self.back.as_ref().map(|b| b.reborrow()), | |
365 | }; | |
8bb4bdeb XL |
366 | f.debug_list().entries(range).finish() |
367 | } | |
368 | } | |
369 | ||
cc61c64b XL |
370 | /// An iterator over the keys of a `BTreeMap`. |
371 | /// | |
372 | /// This `struct` is created by the [`keys`] method on [`BTreeMap`]. See its | |
373 | /// documentation for more. | |
374 | /// | |
375 | /// [`keys`]: struct.BTreeMap.html#method.keys | |
376 | /// [`BTreeMap`]: struct.BTreeMap.html | |
85aaf69f | 377 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 378 | pub struct Keys<'a, K: 'a, V: 'a> { |
9cc50fc6 | 379 | inner: Iter<'a, K, V>, |
1a4d82fc JJ |
380 | } |
381 | ||
8bb4bdeb | 382 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
383 | impl<K: fmt::Debug, V> fmt::Debug for Keys<'_, K, V> { |
384 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
041b39d2 | 385 | f.debug_list().entries(self.clone()).finish() |
8bb4bdeb XL |
386 | } |
387 | } | |
388 | ||
cc61c64b XL |
389 | /// An iterator over the values of a `BTreeMap`. |
390 | /// | |
391 | /// This `struct` is created by the [`values`] method on [`BTreeMap`]. See its | |
392 | /// documentation for more. | |
393 | /// | |
394 | /// [`values`]: struct.BTreeMap.html#method.values | |
395 | /// [`BTreeMap`]: struct.BTreeMap.html | |
85aaf69f | 396 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 397 | pub struct Values<'a, K: 'a, V: 'a> { |
9cc50fc6 | 398 | inner: Iter<'a, K, V>, |
85aaf69f SL |
399 | } |
400 | ||
8bb4bdeb | 401 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
402 | impl<K, V: fmt::Debug> fmt::Debug for Values<'_, K, V> { |
403 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
041b39d2 | 404 | f.debug_list().entries(self.clone()).finish() |
8bb4bdeb XL |
405 | } |
406 | } | |
407 | ||
cc61c64b XL |
408 | /// A mutable iterator over the values of a `BTreeMap`. |
409 | /// | |
410 | /// This `struct` is created by the [`values_mut`] method on [`BTreeMap`]. See its | |
411 | /// documentation for more. | |
412 | /// | |
413 | /// [`values_mut`]: struct.BTreeMap.html#method.values_mut | |
414 | /// [`BTreeMap`]: struct.BTreeMap.html | |
a7813a04 | 415 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
8bb4bdeb | 416 | #[derive(Debug)] |
54a0048b SL |
417 | pub struct ValuesMut<'a, K: 'a, V: 'a> { |
418 | inner: IterMut<'a, K, V>, | |
419 | } | |
420 | ||
cc61c64b XL |
421 | /// An iterator over a sub-range of entries in a `BTreeMap`. |
422 | /// | |
423 | /// This `struct` is created by the [`range`] method on [`BTreeMap`]. See its | |
424 | /// documentation for more. | |
425 | /// | |
426 | /// [`range`]: struct.BTreeMap.html#method.range | |
427 | /// [`BTreeMap`]: struct.BTreeMap.html | |
8bb4bdeb | 428 | #[stable(feature = "btree_range", since = "1.17.0")] |
85aaf69f | 429 | pub struct Range<'a, K: 'a, V: 'a> { |
ba9703b0 XL |
430 | front: Option<Handle<NodeRef<marker::Immut<'a>, K, V, marker::Leaf>, marker::Edge>>, |
431 | back: Option<Handle<NodeRef<marker::Immut<'a>, K, V, marker::Leaf>, marker::Edge>>, | |
85aaf69f SL |
432 | } |
433 | ||
8bb4bdeb | 434 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
435 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Range<'_, K, V> { |
436 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
8bb4bdeb XL |
437 | f.debug_list().entries(self.clone()).finish() |
438 | } | |
439 | } | |
440 | ||
cc61c64b XL |
441 | /// A mutable iterator over a sub-range of entries in a `BTreeMap`. |
442 | /// | |
443 | /// This `struct` is created by the [`range_mut`] method on [`BTreeMap`]. See its | |
444 | /// documentation for more. | |
445 | /// | |
446 | /// [`range_mut`]: struct.BTreeMap.html#method.range_mut | |
447 | /// [`BTreeMap`]: struct.BTreeMap.html | |
8bb4bdeb | 448 | #[stable(feature = "btree_range", since = "1.17.0")] |
85aaf69f | 449 | pub struct RangeMut<'a, K: 'a, V: 'a> { |
ba9703b0 XL |
450 | front: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>, |
451 | back: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>, | |
9cc50fc6 SL |
452 | |
453 | // Be invariant in `K` and `V` | |
454 | _marker: PhantomData<&'a mut (K, V)>, | |
1a4d82fc JJ |
455 | } |
456 | ||
8bb4bdeb | 457 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
458 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for RangeMut<'_, K, V> { |
459 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
ba9703b0 XL |
460 | let range = Range { |
461 | front: self.front.as_ref().map(|f| f.reborrow()), | |
462 | back: self.back.as_ref().map(|b| b.reborrow()), | |
463 | }; | |
8bb4bdeb XL |
464 | f.debug_list().entries(range).finish() |
465 | } | |
466 | } | |
467 | ||
1a4d82fc | 468 | /// A view into a single entry in a map, which may either be vacant or occupied. |
cc61c64b XL |
469 | /// |
470 | /// This `enum` is constructed from the [`entry`] method on [`BTreeMap`]. | |
5bcae85e SL |
471 | /// |
472 | /// [`BTreeMap`]: struct.BTreeMap.html | |
473 | /// [`entry`]: struct.BTreeMap.html#method.entry | |
c34b1796 | 474 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 | 475 | pub enum Entry<'a, K: 'a, V: 'a> { |
cc61c64b | 476 | /// A vacant entry. |
c34b1796 | 477 | #[stable(feature = "rust1", since = "1.0.0")] |
dfeec247 | 478 | Vacant(#[stable(feature = "rust1", since = "1.0.0")] VacantEntry<'a, K, V>), |
c34b1796 | 479 | |
cc61c64b | 480 | /// An occupied entry. |
c34b1796 | 481 | #[stable(feature = "rust1", since = "1.0.0")] |
dfeec247 | 482 | Occupied(#[stable(feature = "rust1", since = "1.0.0")] OccupiedEntry<'a, K, V>), |
1a4d82fc JJ |
483 | } |
484 | ||
dfeec247 | 485 | #[stable(feature = "debug_btree_map", since = "1.12.0")] |
9fa01778 XL |
486 | impl<K: Debug + Ord, V: Debug> Debug for Entry<'_, K, V> { |
487 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
5bcae85e | 488 | match *self { |
dfeec247 XL |
489 | Vacant(ref v) => f.debug_tuple("Entry").field(v).finish(), |
490 | Occupied(ref o) => f.debug_tuple("Entry").field(o).finish(), | |
5bcae85e SL |
491 | } |
492 | } | |
493 | } | |
494 | ||
cc61c64b XL |
495 | /// A view into a vacant entry in a `BTreeMap`. |
496 | /// It is part of the [`Entry`] enum. | |
5bcae85e SL |
497 | /// |
498 | /// [`Entry`]: enum.Entry.html | |
c34b1796 | 499 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 | 500 | pub struct VacantEntry<'a, K: 'a, V: 'a> { |
1a4d82fc | 501 | key: K, |
9cc50fc6 SL |
502 | handle: Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>, |
503 | length: &'a mut usize, | |
504 | ||
505 | // Be invariant in `K` and `V` | |
506 | _marker: PhantomData<&'a mut (K, V)>, | |
1a4d82fc JJ |
507 | } |
508 | ||
dfeec247 | 509 | #[stable(feature = "debug_btree_map", since = "1.12.0")] |
9fa01778 XL |
510 | impl<K: Debug + Ord, V> Debug for VacantEntry<'_, K, V> { |
511 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
dfeec247 | 512 | f.debug_tuple("VacantEntry").field(self.key()).finish() |
5bcae85e SL |
513 | } |
514 | } | |
515 | ||
cc61c64b XL |
516 | /// A view into an occupied entry in a `BTreeMap`. |
517 | /// It is part of the [`Entry`] enum. | |
5bcae85e SL |
518 | /// |
519 | /// [`Entry`]: enum.Entry.html | |
c34b1796 | 520 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 | 521 | pub struct OccupiedEntry<'a, K: 'a, V: 'a> { |
3157f602 | 522 | handle: Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::KV>, |
9cc50fc6 SL |
523 | |
524 | length: &'a mut usize, | |
525 | ||
526 | // Be invariant in `K` and `V` | |
527 | _marker: PhantomData<&'a mut (K, V)>, | |
1a4d82fc JJ |
528 | } |
529 | ||
dfeec247 | 530 | #[stable(feature = "debug_btree_map", since = "1.12.0")] |
9fa01778 XL |
531 | impl<K: Debug + Ord, V: Debug> Debug for OccupiedEntry<'_, K, V> { |
532 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
dfeec247 | 533 | f.debug_struct("OccupiedEntry").field("key", self.key()).field("value", self.get()).finish() |
5bcae85e SL |
534 | } |
535 | } | |
536 | ||
a7813a04 | 537 | // An iterator for merging two sorted sequences into one |
3157f602 | 538 | struct MergeIter<K, V, I: Iterator<Item = (K, V)>> { |
a7813a04 XL |
539 | left: Peekable<I>, |
540 | right: Peekable<I>, | |
541 | } | |
542 | ||
1a4d82fc JJ |
543 | impl<K: Ord, V> BTreeMap<K, V> { |
544 | /// Makes a new empty BTreeMap with a reasonable choice for B. | |
54a0048b SL |
545 | /// |
546 | /// # Examples | |
547 | /// | |
548 | /// Basic usage: | |
549 | /// | |
550 | /// ``` | |
551 | /// use std::collections::BTreeMap; | |
552 | /// | |
553 | /// let mut map = BTreeMap::new(); | |
554 | /// | |
555 | /// // entries can now be inserted into the empty map | |
556 | /// map.insert(1, "a"); | |
557 | /// ``` | |
85aaf69f | 558 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 559 | pub fn new() -> BTreeMap<K, V> { |
ba9703b0 | 560 | BTreeMap { root: None, length: 0 } |
1a4d82fc JJ |
561 | } |
562 | ||
dfeec247 | 563 | /// Clears the map, removing all elements. |
1a4d82fc JJ |
564 | /// |
565 | /// # Examples | |
566 | /// | |
54a0048b SL |
567 | /// Basic usage: |
568 | /// | |
1a4d82fc JJ |
569 | /// ``` |
570 | /// use std::collections::BTreeMap; | |
571 | /// | |
572 | /// let mut a = BTreeMap::new(); | |
85aaf69f | 573 | /// a.insert(1, "a"); |
1a4d82fc JJ |
574 | /// a.clear(); |
575 | /// assert!(a.is_empty()); | |
576 | /// ``` | |
85aaf69f | 577 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 578 | pub fn clear(&mut self) { |
9cc50fc6 | 579 | *self = BTreeMap::new(); |
1a4d82fc JJ |
580 | } |
581 | ||
1a4d82fc JJ |
582 | /// Returns a reference to the value corresponding to the key. |
583 | /// | |
584 | /// The key may be any borrowed form of the map's key type, but the ordering | |
585 | /// on the borrowed form *must* match the ordering on the key type. | |
586 | /// | |
587 | /// # Examples | |
588 | /// | |
54a0048b SL |
589 | /// Basic usage: |
590 | /// | |
1a4d82fc JJ |
591 | /// ``` |
592 | /// use std::collections::BTreeMap; | |
593 | /// | |
594 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 595 | /// map.insert(1, "a"); |
1a4d82fc JJ |
596 | /// assert_eq!(map.get(&1), Some(&"a")); |
597 | /// assert_eq!(map.get(&2), None); | |
598 | /// ``` | |
85aaf69f | 599 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 600 | pub fn get<Q: ?Sized>(&self, key: &Q) -> Option<&V> |
dfeec247 XL |
601 | where |
602 | K: Borrow<Q>, | |
603 | Q: Ord, | |
3157f602 | 604 | { |
ba9703b0 | 605 | match search::search_tree(self.root.as_ref()?.as_ref(), key) { |
9cc50fc6 | 606 | Found(handle) => Some(handle.into_kv().1), |
3157f602 | 607 | GoDown(_) => None, |
1a4d82fc JJ |
608 | } |
609 | } | |
610 | ||
0531ce1d XL |
611 | /// Returns the key-value pair corresponding to the supplied key. |
612 | /// | |
613 | /// The supplied key may be any borrowed form of the map's key type, but the ordering | |
614 | /// on the borrowed form *must* match the ordering on the key type. | |
615 | /// | |
616 | /// # Examples | |
617 | /// | |
618 | /// ``` | |
0531ce1d XL |
619 | /// use std::collections::BTreeMap; |
620 | /// | |
621 | /// let mut map = BTreeMap::new(); | |
622 | /// map.insert(1, "a"); | |
623 | /// assert_eq!(map.get_key_value(&1), Some((&1, &"a"))); | |
624 | /// assert_eq!(map.get_key_value(&2), None); | |
625 | /// ``` | |
e74abb32 | 626 | #[stable(feature = "map_get_key_value", since = "1.40.0")] |
0531ce1d | 627 | pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)> |
dfeec247 XL |
628 | where |
629 | K: Borrow<Q>, | |
630 | Q: Ord, | |
0531ce1d | 631 | { |
ba9703b0 | 632 | match search::search_tree(self.root.as_ref()?.as_ref(), k) { |
0531ce1d XL |
633 | Found(handle) => Some(handle.into_kv()), |
634 | GoDown(_) => None, | |
635 | } | |
636 | } | |
637 | ||
60c5eb7d XL |
638 | /// Returns the first key-value pair in the map. |
639 | /// The key in this pair is the minimum key in the map. | |
640 | /// | |
641 | /// # Examples | |
642 | /// | |
643 | /// Basic usage: | |
644 | /// | |
645 | /// ``` | |
646 | /// #![feature(map_first_last)] | |
647 | /// use std::collections::BTreeMap; | |
648 | /// | |
649 | /// let mut map = BTreeMap::new(); | |
650 | /// assert_eq!(map.first_key_value(), None); | |
651 | /// map.insert(1, "b"); | |
652 | /// map.insert(2, "a"); | |
653 | /// assert_eq!(map.first_key_value(), Some((&1, &"b"))); | |
654 | /// ``` | |
655 | #[unstable(feature = "map_first_last", issue = "62924")] | |
ba9703b0 XL |
656 | pub fn first_key_value(&self) -> Option<(&K, &V)> { |
657 | let front = self.root.as_ref()?.as_ref().first_leaf_edge(); | |
60c5eb7d XL |
658 | front.right_kv().ok().map(Handle::into_kv) |
659 | } | |
660 | ||
661 | /// Returns the first entry in the map for in-place manipulation. | |
662 | /// The key of this entry is the minimum key in the map. | |
663 | /// | |
664 | /// # Examples | |
665 | /// | |
ba9703b0 XL |
666 | /// ``` |
667 | /// #![feature(map_first_last)] | |
668 | /// use std::collections::BTreeMap; | |
669 | /// | |
670 | /// let mut map = BTreeMap::new(); | |
671 | /// map.insert(1, "a"); | |
672 | /// map.insert(2, "b"); | |
673 | /// if let Some(mut entry) = map.first_entry() { | |
674 | /// if *entry.key() > 0 { | |
675 | /// entry.insert("first"); | |
676 | /// } | |
677 | /// } | |
678 | /// assert_eq!(*map.get(&1).unwrap(), "first"); | |
679 | /// assert_eq!(*map.get(&2).unwrap(), "b"); | |
680 | /// ``` | |
681 | #[unstable(feature = "map_first_last", issue = "62924")] | |
682 | pub fn first_entry(&mut self) -> Option<OccupiedEntry<'_, K, V>> { | |
683 | let front = self.root.as_mut()?.as_mut().first_leaf_edge(); | |
684 | let kv = front.right_kv().ok()?; | |
685 | Some(OccupiedEntry { | |
686 | handle: kv.forget_node_type(), | |
687 | length: &mut self.length, | |
688 | _marker: PhantomData, | |
689 | }) | |
690 | } | |
691 | ||
692 | /// Removes and returns the first element in the map. | |
693 | /// The key of this element is the minimum key that was in the map. | |
694 | /// | |
695 | /// # Examples | |
696 | /// | |
697 | /// Draining elements in ascending order, while keeping a usable map each iteration. | |
60c5eb7d XL |
698 | /// |
699 | /// ``` | |
700 | /// #![feature(map_first_last)] | |
701 | /// use std::collections::BTreeMap; | |
702 | /// | |
703 | /// let mut map = BTreeMap::new(); | |
704 | /// map.insert(1, "a"); | |
705 | /// map.insert(2, "b"); | |
ba9703b0 XL |
706 | /// while let Some((key, _val)) = map.pop_first() { |
707 | /// assert!(map.iter().all(|(k, _v)| *k > key)); | |
60c5eb7d | 708 | /// } |
ba9703b0 | 709 | /// assert!(map.is_empty()); |
60c5eb7d XL |
710 | /// ``` |
711 | #[unstable(feature = "map_first_last", issue = "62924")] | |
ba9703b0 XL |
712 | pub fn pop_first(&mut self) -> Option<(K, V)> { |
713 | self.first_entry().map(|entry| entry.remove_entry()) | |
60c5eb7d XL |
714 | } |
715 | ||
716 | /// Returns the last key-value pair in the map. | |
717 | /// The key in this pair is the maximum key in the map. | |
718 | /// | |
719 | /// # Examples | |
720 | /// | |
721 | /// Basic usage: | |
722 | /// | |
723 | /// ``` | |
724 | /// #![feature(map_first_last)] | |
725 | /// use std::collections::BTreeMap; | |
726 | /// | |
727 | /// let mut map = BTreeMap::new(); | |
728 | /// map.insert(1, "b"); | |
729 | /// map.insert(2, "a"); | |
730 | /// assert_eq!(map.last_key_value(), Some((&2, &"a"))); | |
731 | /// ``` | |
732 | #[unstable(feature = "map_first_last", issue = "62924")] | |
ba9703b0 XL |
733 | pub fn last_key_value(&self) -> Option<(&K, &V)> { |
734 | let back = self.root.as_ref()?.as_ref().last_leaf_edge(); | |
60c5eb7d XL |
735 | back.left_kv().ok().map(Handle::into_kv) |
736 | } | |
737 | ||
738 | /// Returns the last entry in the map for in-place manipulation. | |
739 | /// The key of this entry is the maximum key in the map. | |
740 | /// | |
741 | /// # Examples | |
742 | /// | |
ba9703b0 XL |
743 | /// ``` |
744 | /// #![feature(map_first_last)] | |
745 | /// use std::collections::BTreeMap; | |
746 | /// | |
747 | /// let mut map = BTreeMap::new(); | |
748 | /// map.insert(1, "a"); | |
749 | /// map.insert(2, "b"); | |
750 | /// if let Some(mut entry) = map.last_entry() { | |
751 | /// if *entry.key() > 0 { | |
752 | /// entry.insert("last"); | |
753 | /// } | |
754 | /// } | |
755 | /// assert_eq!(*map.get(&1).unwrap(), "a"); | |
756 | /// assert_eq!(*map.get(&2).unwrap(), "last"); | |
757 | /// ``` | |
758 | #[unstable(feature = "map_first_last", issue = "62924")] | |
759 | pub fn last_entry(&mut self) -> Option<OccupiedEntry<'_, K, V>> { | |
760 | let back = self.root.as_mut()?.as_mut().last_leaf_edge(); | |
761 | let kv = back.left_kv().ok()?; | |
762 | Some(OccupiedEntry { | |
763 | handle: kv.forget_node_type(), | |
764 | length: &mut self.length, | |
765 | _marker: PhantomData, | |
766 | }) | |
767 | } | |
768 | ||
769 | /// Removes and returns the last element in the map. | |
770 | /// The key of this element is the maximum key that was in the map. | |
771 | /// | |
772 | /// # Examples | |
773 | /// | |
774 | /// Draining elements in descending order, while keeping a usable map each iteration. | |
60c5eb7d XL |
775 | /// |
776 | /// ``` | |
777 | /// #![feature(map_first_last)] | |
778 | /// use std::collections::BTreeMap; | |
779 | /// | |
780 | /// let mut map = BTreeMap::new(); | |
781 | /// map.insert(1, "a"); | |
782 | /// map.insert(2, "b"); | |
ba9703b0 XL |
783 | /// while let Some((key, _val)) = map.pop_last() { |
784 | /// assert!(map.iter().all(|(k, _v)| *k < key)); | |
60c5eb7d | 785 | /// } |
ba9703b0 | 786 | /// assert!(map.is_empty()); |
60c5eb7d XL |
787 | /// ``` |
788 | #[unstable(feature = "map_first_last", issue = "62924")] | |
ba9703b0 XL |
789 | pub fn pop_last(&mut self) -> Option<(K, V)> { |
790 | self.last_entry().map(|entry| entry.remove_entry()) | |
60c5eb7d XL |
791 | } |
792 | ||
cc61c64b | 793 | /// Returns `true` if the map contains a value for the specified key. |
1a4d82fc JJ |
794 | /// |
795 | /// The key may be any borrowed form of the map's key type, but the ordering | |
796 | /// on the borrowed form *must* match the ordering on the key type. | |
797 | /// | |
798 | /// # Examples | |
799 | /// | |
54a0048b SL |
800 | /// Basic usage: |
801 | /// | |
1a4d82fc JJ |
802 | /// ``` |
803 | /// use std::collections::BTreeMap; | |
804 | /// | |
805 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 806 | /// map.insert(1, "a"); |
1a4d82fc JJ |
807 | /// assert_eq!(map.contains_key(&1), true); |
808 | /// assert_eq!(map.contains_key(&2), false); | |
809 | /// ``` | |
85aaf69f | 810 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 811 | pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool |
dfeec247 XL |
812 | where |
813 | K: Borrow<Q>, | |
814 | Q: Ord, | |
3157f602 | 815 | { |
1a4d82fc JJ |
816 | self.get(key).is_some() |
817 | } | |
818 | ||
819 | /// Returns a mutable reference to the value corresponding to the key. | |
820 | /// | |
821 | /// The key may be any borrowed form of the map's key type, but the ordering | |
822 | /// on the borrowed form *must* match the ordering on the key type. | |
823 | /// | |
824 | /// # Examples | |
825 | /// | |
54a0048b SL |
826 | /// Basic usage: |
827 | /// | |
1a4d82fc JJ |
828 | /// ``` |
829 | /// use std::collections::BTreeMap; | |
830 | /// | |
831 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 832 | /// map.insert(1, "a"); |
9346a6ac AL |
833 | /// if let Some(x) = map.get_mut(&1) { |
834 | /// *x = "b"; | |
1a4d82fc | 835 | /// } |
c34b1796 | 836 | /// assert_eq!(map[&1], "b"); |
1a4d82fc JJ |
837 | /// ``` |
838 | // See `get` for implementation notes, this is basically a copy-paste with mut's added | |
85aaf69f | 839 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 840 | pub fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V> |
dfeec247 XL |
841 | where |
842 | K: Borrow<Q>, | |
843 | Q: Ord, | |
3157f602 | 844 | { |
ba9703b0 | 845 | match search::search_tree(self.root.as_mut()?.as_mut(), key) { |
9cc50fc6 | 846 | Found(handle) => Some(handle.into_kv_mut().1), |
3157f602 | 847 | GoDown(_) => None, |
1a4d82fc JJ |
848 | } |
849 | } | |
850 | ||
b039eaaf SL |
851 | /// Inserts a key-value pair into the map. |
852 | /// | |
853 | /// If the map did not have this key present, `None` is returned. | |
854 | /// | |
7453a54e SL |
855 | /// If the map did have this key present, the value is updated, and the old |
856 | /// value is returned. The key is not updated, though; this matters for | |
857 | /// types that can be `==` without being identical. See the [module-level | |
858 | /// documentation] for more. | |
b039eaaf SL |
859 | /// |
860 | /// [module-level documentation]: index.html#insert-and-complex-keys | |
1a4d82fc JJ |
861 | /// |
862 | /// # Examples | |
863 | /// | |
54a0048b SL |
864 | /// Basic usage: |
865 | /// | |
1a4d82fc JJ |
866 | /// ``` |
867 | /// use std::collections::BTreeMap; | |
868 | /// | |
869 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 870 | /// assert_eq!(map.insert(37, "a"), None); |
1a4d82fc JJ |
871 | /// assert_eq!(map.is_empty(), false); |
872 | /// | |
873 | /// map.insert(37, "b"); | |
874 | /// assert_eq!(map.insert(37, "c"), Some("b")); | |
c34b1796 | 875 | /// assert_eq!(map[&37], "c"); |
1a4d82fc | 876 | /// ``` |
85aaf69f | 877 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
878 | pub fn insert(&mut self, key: K, value: V) -> Option<V> { |
879 | match self.entry(key) { | |
880 | Occupied(mut entry) => Some(entry.insert(value)), | |
881 | Vacant(entry) => { | |
882 | entry.insert(value); | |
883 | None | |
1a4d82fc JJ |
884 | } |
885 | } | |
886 | } | |
887 | ||
1a4d82fc JJ |
888 | /// Removes a key from the map, returning the value at the key if the key |
889 | /// was previously in the map. | |
890 | /// | |
891 | /// The key may be any borrowed form of the map's key type, but the ordering | |
892 | /// on the borrowed form *must* match the ordering on the key type. | |
893 | /// | |
894 | /// # Examples | |
895 | /// | |
54a0048b SL |
896 | /// Basic usage: |
897 | /// | |
1a4d82fc JJ |
898 | /// ``` |
899 | /// use std::collections::BTreeMap; | |
900 | /// | |
901 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 902 | /// map.insert(1, "a"); |
1a4d82fc JJ |
903 | /// assert_eq!(map.remove(&1), Some("a")); |
904 | /// assert_eq!(map.remove(&1), None); | |
905 | /// ``` | |
85aaf69f | 906 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 907 | pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V> |
74b04a01 XL |
908 | where |
909 | K: Borrow<Q>, | |
910 | Q: Ord, | |
911 | { | |
912 | self.remove_entry(key).map(|(_, v)| v) | |
913 | } | |
914 | ||
915 | /// Removes a key from the map, returning the stored key and value if the key | |
916 | /// was previously in the map. | |
917 | /// | |
918 | /// The key may be any borrowed form of the map's key type, but the ordering | |
919 | /// on the borrowed form *must* match the ordering on the key type. | |
920 | /// | |
921 | /// # Examples | |
922 | /// | |
923 | /// Basic usage: | |
924 | /// | |
925 | /// ``` | |
926 | /// #![feature(btreemap_remove_entry)] | |
927 | /// use std::collections::BTreeMap; | |
928 | /// | |
929 | /// let mut map = BTreeMap::new(); | |
930 | /// map.insert(1, "a"); | |
931 | /// assert_eq!(map.remove_entry(&1), Some((1, "a"))); | |
932 | /// assert_eq!(map.remove_entry(&1), None); | |
933 | /// ``` | |
934 | #[unstable(feature = "btreemap_remove_entry", issue = "66714")] | |
935 | pub fn remove_entry<Q: ?Sized>(&mut self, key: &Q) -> Option<(K, V)> | |
dfeec247 XL |
936 | where |
937 | K: Borrow<Q>, | |
938 | Q: Ord, | |
3157f602 | 939 | { |
ba9703b0 | 940 | match search::search_tree(self.root.as_mut()?.as_mut(), key) { |
dfeec247 | 941 | Found(handle) => Some( |
74b04a01 XL |
942 | OccupiedEntry { handle, length: &mut self.length, _marker: PhantomData } |
943 | .remove_entry(), | |
dfeec247 | 944 | ), |
3157f602 | 945 | GoDown(_) => None, |
1a4d82fc JJ |
946 | } |
947 | } | |
85aaf69f | 948 | |
a7813a04 XL |
949 | /// Moves all elements from `other` into `Self`, leaving `other` empty. |
950 | /// | |
951 | /// # Examples | |
952 | /// | |
953 | /// ``` | |
a7813a04 XL |
954 | /// use std::collections::BTreeMap; |
955 | /// | |
956 | /// let mut a = BTreeMap::new(); | |
957 | /// a.insert(1, "a"); | |
958 | /// a.insert(2, "b"); | |
959 | /// a.insert(3, "c"); | |
960 | /// | |
961 | /// let mut b = BTreeMap::new(); | |
962 | /// b.insert(3, "d"); | |
963 | /// b.insert(4, "e"); | |
964 | /// b.insert(5, "f"); | |
965 | /// | |
966 | /// a.append(&mut b); | |
967 | /// | |
968 | /// assert_eq!(a.len(), 5); | |
969 | /// assert_eq!(b.len(), 0); | |
970 | /// | |
971 | /// assert_eq!(a[&1], "a"); | |
972 | /// assert_eq!(a[&2], "b"); | |
973 | /// assert_eq!(a[&3], "d"); | |
974 | /// assert_eq!(a[&4], "e"); | |
975 | /// assert_eq!(a[&5], "f"); | |
976 | /// ``` | |
3157f602 | 977 | #[stable(feature = "btree_append", since = "1.11.0")] |
a7813a04 XL |
978 | pub fn append(&mut self, other: &mut Self) { |
979 | // Do we have to append anything at all? | |
416331ca | 980 | if other.is_empty() { |
a7813a04 XL |
981 | return; |
982 | } | |
983 | ||
984 | // We can just swap `self` and `other` if `self` is empty. | |
416331ca | 985 | if self.is_empty() { |
a7813a04 XL |
986 | mem::swap(self, other); |
987 | return; | |
988 | } | |
989 | ||
990 | // First, we merge `self` and `other` into a sorted sequence in linear time. | |
416331ca XL |
991 | let self_iter = mem::take(self).into_iter(); |
992 | let other_iter = mem::take(other).into_iter(); | |
dfeec247 | 993 | let iter = MergeIter { left: self_iter.peekable(), right: other_iter.peekable() }; |
a7813a04 XL |
994 | |
995 | // Second, we build a tree from the sorted sequence in linear time. | |
996 | self.from_sorted_iter(iter); | |
997 | self.fix_right_edge(); | |
998 | } | |
999 | ||
32a655c1 SL |
1000 | /// Constructs a double-ended iterator over a sub-range of elements in the map. |
1001 | /// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will | |
1002 | /// yield elements from min (inclusive) to max (exclusive). | |
1003 | /// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example | |
1004 | /// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive | |
1005 | /// range from 4 to 10. | |
9346a6ac | 1006 | /// |
8bb4bdeb XL |
1007 | /// # Panics |
1008 | /// | |
1009 | /// Panics if range `start > end`. | |
1010 | /// Panics if range `start == end` and both bounds are `Excluded`. | |
1011 | /// | |
9346a6ac AL |
1012 | /// # Examples |
1013 | /// | |
54a0048b SL |
1014 | /// Basic usage: |
1015 | /// | |
9346a6ac AL |
1016 | /// ``` |
1017 | /// use std::collections::BTreeMap; | |
0531ce1d | 1018 | /// use std::ops::Bound::Included; |
9346a6ac AL |
1019 | /// |
1020 | /// let mut map = BTreeMap::new(); | |
9cc50fc6 SL |
1021 | /// map.insert(3, "a"); |
1022 | /// map.insert(5, "b"); | |
1023 | /// map.insert(8, "c"); | |
32a655c1 | 1024 | /// for (&key, &value) in map.range((Included(&4), Included(&8))) { |
9346a6ac AL |
1025 | /// println!("{}: {}", key, value); |
1026 | /// } | |
32a655c1 | 1027 | /// assert_eq!(Some((&5, &"b")), map.range(4..).next()); |
9346a6ac | 1028 | /// ``` |
8bb4bdeb | 1029 | #[stable(feature = "btree_range", since = "1.17.0")] |
9fa01778 | 1030 | pub fn range<T: ?Sized, R>(&self, range: R) -> Range<'_, K, V> |
dfeec247 XL |
1031 | where |
1032 | T: Ord, | |
1033 | K: Borrow<T>, | |
1034 | R: RangeBounds<T>, | |
9cc50fc6 | 1035 | { |
ba9703b0 XL |
1036 | if let Some(root) = &self.root { |
1037 | let root1 = root.as_ref(); | |
1038 | let root2 = root.as_ref(); | |
1039 | let (f, b) = range_search(root1, root2, range); | |
9cc50fc6 | 1040 | |
ba9703b0 XL |
1041 | Range { front: Some(f), back: Some(b) } |
1042 | } else { | |
1043 | Range { front: None, back: None } | |
1044 | } | |
9cc50fc6 SL |
1045 | } |
1046 | ||
32a655c1 SL |
1047 | /// Constructs a mutable double-ended iterator over a sub-range of elements in the map. |
1048 | /// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will | |
1049 | /// yield elements from min (inclusive) to max (exclusive). | |
1050 | /// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example | |
1051 | /// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive | |
1052 | /// range from 4 to 10. | |
9cc50fc6 | 1053 | /// |
8bb4bdeb XL |
1054 | /// # Panics |
1055 | /// | |
1056 | /// Panics if range `start > end`. | |
1057 | /// Panics if range `start == end` and both bounds are `Excluded`. | |
1058 | /// | |
9cc50fc6 SL |
1059 | /// # Examples |
1060 | /// | |
54a0048b SL |
1061 | /// Basic usage: |
1062 | /// | |
9cc50fc6 | 1063 | /// ``` |
9cc50fc6 | 1064 | /// use std::collections::BTreeMap; |
9cc50fc6 | 1065 | /// |
a1dfa0c6 XL |
1066 | /// let mut map: BTreeMap<&str, i32> = ["Alice", "Bob", "Carol", "Cheryl"] |
1067 | /// .iter() | |
1068 | /// .map(|&s| (s, 0)) | |
1069 | /// .collect(); | |
32a655c1 | 1070 | /// for (_, balance) in map.range_mut("B".."Cheryl") { |
9cc50fc6 SL |
1071 | /// *balance += 100; |
1072 | /// } | |
1073 | /// for (name, balance) in &map { | |
1074 | /// println!("{} => {}", name, balance); | |
1075 | /// } | |
1076 | /// ``` | |
8bb4bdeb | 1077 | #[stable(feature = "btree_range", since = "1.17.0")] |
9fa01778 | 1078 | pub fn range_mut<T: ?Sized, R>(&mut self, range: R) -> RangeMut<'_, K, V> |
dfeec247 XL |
1079 | where |
1080 | T: Ord, | |
1081 | K: Borrow<T>, | |
1082 | R: RangeBounds<T>, | |
9cc50fc6 | 1083 | { |
ba9703b0 XL |
1084 | if let Some(root) = &mut self.root { |
1085 | let root1 = root.as_mut(); | |
1086 | let root2 = unsafe { ptr::read(&root1) }; | |
1087 | let (f, b) = range_search(root1, root2, range); | |
9cc50fc6 | 1088 | |
ba9703b0 XL |
1089 | RangeMut { front: Some(f), back: Some(b), _marker: PhantomData } |
1090 | } else { | |
1091 | RangeMut { front: None, back: None, _marker: PhantomData } | |
1092 | } | |
9cc50fc6 SL |
1093 | } |
1094 | ||
1095 | /// Gets the given key's corresponding entry in the map for in-place manipulation. | |
1096 | /// | |
1097 | /// # Examples | |
1098 | /// | |
54a0048b SL |
1099 | /// Basic usage: |
1100 | /// | |
9cc50fc6 SL |
1101 | /// ``` |
1102 | /// use std::collections::BTreeMap; | |
1103 | /// | |
1104 | /// let mut count: BTreeMap<&str, usize> = BTreeMap::new(); | |
1105 | /// | |
1106 | /// // count the number of occurrences of letters in the vec | |
1107 | /// for x in vec!["a","b","a","c","a","b"] { | |
1108 | /// *count.entry(x).or_insert(0) += 1; | |
1109 | /// } | |
1110 | /// | |
1111 | /// assert_eq!(count["a"], 3); | |
1112 | /// ``` | |
1113 | #[stable(feature = "rust1", since = "1.0.0")] | |
9fa01778 | 1114 | pub fn entry(&mut self, key: K) -> Entry<'_, K, V> { |
94b46f34 XL |
1115 | // FIXME(@porglezomp) Avoid allocating if we don't insert |
1116 | self.ensure_root_is_owned(); | |
ba9703b0 | 1117 | match search::search_tree(self.root.as_mut().unwrap().as_mut(), &key) { |
3157f602 | 1118 | Found(handle) => { |
dfeec247 | 1119 | Occupied(OccupiedEntry { handle, length: &mut self.length, _marker: PhantomData }) |
3157f602 XL |
1120 | } |
1121 | GoDown(handle) => { | |
dfeec247 | 1122 | Vacant(VacantEntry { key, handle, length: &mut self.length, _marker: PhantomData }) |
3157f602 | 1123 | } |
9346a6ac | 1124 | } |
85aaf69f | 1125 | } |
a7813a04 | 1126 | |
3157f602 | 1127 | fn from_sorted_iter<I: Iterator<Item = (K, V)>>(&mut self, iter: I) { |
94b46f34 | 1128 | self.ensure_root_is_owned(); |
ba9703b0 | 1129 | let mut cur_node = self.root.as_mut().unwrap().as_mut().last_leaf_edge().into_node(); |
a7813a04 XL |
1130 | // Iterate through all key-value pairs, pushing them into nodes at the right level. |
1131 | for (key, value) in iter { | |
1132 | // Try to push key-value pair into the current leaf node. | |
1133 | if cur_node.len() < node::CAPACITY { | |
1134 | cur_node.push(key, value); | |
1135 | } else { | |
1136 | // No space left, go up and push there. | |
1137 | let mut open_node; | |
1138 | let mut test_node = cur_node.forget_type(); | |
1139 | loop { | |
1140 | match test_node.ascend() { | |
1141 | Ok(parent) => { | |
1142 | let parent = parent.into_node(); | |
1143 | if parent.len() < node::CAPACITY { | |
1144 | // Found a node with space left, push here. | |
1145 | open_node = parent; | |
1146 | break; | |
1147 | } else { | |
1148 | // Go up again. | |
1149 | test_node = parent.forget_type(); | |
1150 | } | |
3157f602 | 1151 | } |
a7813a04 XL |
1152 | Err(node) => { |
1153 | // We are at the top, create a new root node and push there. | |
1154 | open_node = node.into_root_mut().push_level(); | |
1155 | break; | |
3157f602 | 1156 | } |
a7813a04 XL |
1157 | } |
1158 | } | |
1159 | ||
1160 | // Push key-value pair and new right subtree. | |
1161 | let tree_height = open_node.height() - 1; | |
1162 | let mut right_tree = node::Root::new_leaf(); | |
1163 | for _ in 0..tree_height { | |
1164 | right_tree.push_level(); | |
1165 | } | |
1166 | open_node.push(key, value, right_tree); | |
1167 | ||
1168 | // Go down to the right-most leaf again. | |
74b04a01 | 1169 | cur_node = open_node.forget_type().last_leaf_edge().into_node(); |
a7813a04 XL |
1170 | } |
1171 | ||
1172 | self.length += 1; | |
1173 | } | |
1174 | } | |
1175 | ||
1176 | fn fix_right_edge(&mut self) { | |
1177 | // Handle underfull nodes, start from the top. | |
ba9703b0 | 1178 | let mut cur_node = self.root.as_mut().unwrap().as_mut(); |
a7813a04 XL |
1179 | while let Internal(internal) = cur_node.force() { |
1180 | // Check if right-most child is underfull. | |
1181 | let mut last_edge = internal.last_edge(); | |
1182 | let right_child_len = last_edge.reborrow().descend().len(); | |
3157f602 | 1183 | if right_child_len < node::MIN_LEN { |
a7813a04 XL |
1184 | // We need to steal. |
1185 | let mut last_kv = match last_edge.left_kv() { | |
1186 | Ok(left) => left, | |
1187 | Err(_) => unreachable!(), | |
1188 | }; | |
3157f602 | 1189 | last_kv.bulk_steal_left(node::MIN_LEN - right_child_len); |
a7813a04 XL |
1190 | last_edge = last_kv.right_edge(); |
1191 | } | |
1192 | ||
1193 | // Go further down. | |
1194 | cur_node = last_edge.descend(); | |
1195 | } | |
1196 | } | |
3157f602 XL |
1197 | |
1198 | /// Splits the collection into two at the given key. Returns everything after the given key, | |
1199 | /// including the key. | |
1200 | /// | |
1201 | /// # Examples | |
1202 | /// | |
1203 | /// Basic usage: | |
1204 | /// | |
1205 | /// ``` | |
1206 | /// use std::collections::BTreeMap; | |
1207 | /// | |
1208 | /// let mut a = BTreeMap::new(); | |
1209 | /// a.insert(1, "a"); | |
1210 | /// a.insert(2, "b"); | |
1211 | /// a.insert(3, "c"); | |
1212 | /// a.insert(17, "d"); | |
1213 | /// a.insert(41, "e"); | |
1214 | /// | |
1215 | /// let b = a.split_off(&3); | |
1216 | /// | |
1217 | /// assert_eq!(a.len(), 2); | |
1218 | /// assert_eq!(b.len(), 3); | |
1219 | /// | |
1220 | /// assert_eq!(a[&1], "a"); | |
1221 | /// assert_eq!(a[&2], "b"); | |
1222 | /// | |
1223 | /// assert_eq!(b[&3], "c"); | |
1224 | /// assert_eq!(b[&17], "d"); | |
1225 | /// assert_eq!(b[&41], "e"); | |
1226 | /// ``` | |
1227 | #[stable(feature = "btree_split_off", since = "1.11.0")] | |
1228 | pub fn split_off<Q: ?Sized + Ord>(&mut self, key: &Q) -> Self | |
dfeec247 XL |
1229 | where |
1230 | K: Borrow<Q>, | |
3157f602 XL |
1231 | { |
1232 | if self.is_empty() { | |
1233 | return Self::new(); | |
1234 | } | |
1235 | ||
1236 | let total_num = self.len(); | |
1237 | ||
1238 | let mut right = Self::new(); | |
ba9703b0 XL |
1239 | let right_root = right.ensure_root_is_owned(); |
1240 | for _ in 0..(self.root.as_ref().unwrap().as_ref().height()) { | |
1241 | right_root.push_level(); | |
3157f602 XL |
1242 | } |
1243 | ||
1244 | { | |
ba9703b0 XL |
1245 | let mut left_node = self.root.as_mut().unwrap().as_mut(); |
1246 | let mut right_node = right.root.as_mut().unwrap().as_mut(); | |
3157f602 XL |
1247 | |
1248 | loop { | |
1249 | let mut split_edge = match search::search_node(left_node, key) { | |
1250 | // key is going to the right tree | |
1251 | Found(handle) => handle.left_edge(), | |
1252 | GoDown(handle) => handle, | |
1253 | }; | |
1254 | ||
1255 | split_edge.move_suffix(&mut right_node); | |
1256 | ||
1257 | match (split_edge.force(), right_node.force()) { | |
1258 | (Internal(edge), Internal(node)) => { | |
1259 | left_node = edge.descend(); | |
1260 | right_node = node.first_edge().descend(); | |
1261 | } | |
1262 | (Leaf(_), Leaf(_)) => { | |
1263 | break; | |
1264 | } | |
1265 | _ => { | |
1266 | unreachable!(); | |
1267 | } | |
1268 | } | |
1269 | } | |
1270 | } | |
1271 | ||
1272 | self.fix_right_border(); | |
1273 | right.fix_left_border(); | |
1274 | ||
ba9703b0 XL |
1275 | if self.root.as_ref().unwrap().as_ref().height() |
1276 | < right.root.as_ref().unwrap().as_ref().height() | |
1277 | { | |
3157f602 XL |
1278 | self.recalc_length(); |
1279 | right.length = total_num - self.len(); | |
1280 | } else { | |
1281 | right.recalc_length(); | |
1282 | self.length = total_num - right.len(); | |
1283 | } | |
1284 | ||
1285 | right | |
1286 | } | |
1287 | ||
ba9703b0 XL |
1288 | /// Creates an iterator which uses a closure to determine if an element should be removed. |
1289 | /// | |
1290 | /// If the closure returns true, the element is removed from the map and yielded. | |
1291 | /// If the closure returns false, or panics, the element remains in the map and will not be | |
1292 | /// yielded. | |
1293 | /// | |
1294 | /// Note that `drain_filter` lets you mutate every value in the filter closure, regardless of | |
1295 | /// whether you choose to keep or remove it. | |
1296 | /// | |
1297 | /// If the iterator is only partially consumed or not consumed at all, each of the remaining | |
1298 | /// elements will still be subjected to the closure and removed and dropped if it returns true. | |
1299 | /// | |
1300 | /// It is unspecified how many more elements will be subjected to the closure | |
1301 | /// if a panic occurs in the closure, or a panic occurs while dropping an element, | |
1302 | /// or if the `DrainFilter` value is leaked. | |
1303 | /// | |
1304 | /// # Examples | |
1305 | /// | |
1306 | /// Splitting a map into even and odd keys, reusing the original map: | |
1307 | /// | |
1308 | /// ``` | |
1309 | /// #![feature(btree_drain_filter)] | |
1310 | /// use std::collections::BTreeMap; | |
1311 | /// | |
1312 | /// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x)).collect(); | |
1313 | /// let evens: BTreeMap<_, _> = map.drain_filter(|k, _v| k % 2 == 0).collect(); | |
1314 | /// let odds = map; | |
1315 | /// assert_eq!(evens.keys().copied().collect::<Vec<_>>(), vec![0, 2, 4, 6]); | |
1316 | /// assert_eq!(odds.keys().copied().collect::<Vec<_>>(), vec![1, 3, 5, 7]); | |
1317 | /// ``` | |
1318 | #[unstable(feature = "btree_drain_filter", issue = "70530")] | |
1319 | pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, K, V, F> | |
1320 | where | |
1321 | F: FnMut(&K, &mut V) -> bool, | |
1322 | { | |
1323 | DrainFilter { pred, inner: self.drain_filter_inner() } | |
1324 | } | |
1325 | pub(super) fn drain_filter_inner(&mut self) -> DrainFilterInner<'_, K, V> { | |
1326 | let front = self.root.as_mut().map(|r| r.as_mut().first_leaf_edge()); | |
1327 | DrainFilterInner { length: &mut self.length, cur_leaf_edge: front } | |
1328 | } | |
1329 | ||
3157f602 XL |
1330 | /// Calculates the number of elements if it is incorrect. |
1331 | fn recalc_length(&mut self) { | |
dfeec247 XL |
1332 | fn dfs<'a, K, V>(node: NodeRef<marker::Immut<'a>, K, V, marker::LeafOrInternal>) -> usize |
1333 | where | |
1334 | K: 'a, | |
1335 | V: 'a, | |
8faf50e0 | 1336 | { |
3157f602 XL |
1337 | let mut res = node.len(); |
1338 | ||
1339 | if let Internal(node) = node.force() { | |
1340 | let mut edge = node.first_edge(); | |
1341 | loop { | |
1342 | res += dfs(edge.reborrow().descend()); | |
1343 | match edge.right_kv() { | |
1344 | Ok(right_kv) => { | |
1345 | edge = right_kv.right_edge(); | |
1346 | } | |
1347 | Err(_) => { | |
1348 | break; | |
1349 | } | |
1350 | } | |
1351 | } | |
1352 | } | |
1353 | ||
1354 | res | |
1355 | } | |
1356 | ||
ba9703b0 | 1357 | self.length = dfs(self.root.as_ref().unwrap().as_ref()); |
3157f602 XL |
1358 | } |
1359 | ||
1360 | /// Removes empty levels on the top. | |
1361 | fn fix_top(&mut self) { | |
1362 | loop { | |
1363 | { | |
ba9703b0 | 1364 | let node = self.root.as_ref().unwrap().as_ref(); |
3157f602 XL |
1365 | if node.height() == 0 || node.len() > 0 { |
1366 | break; | |
1367 | } | |
1368 | } | |
ba9703b0 | 1369 | self.root.as_mut().unwrap().pop_level(); |
3157f602 XL |
1370 | } |
1371 | } | |
1372 | ||
1373 | fn fix_right_border(&mut self) { | |
1374 | self.fix_top(); | |
1375 | ||
1376 | { | |
ba9703b0 | 1377 | let mut cur_node = self.root.as_mut().unwrap().as_mut(); |
3157f602 XL |
1378 | |
1379 | while let Internal(node) = cur_node.force() { | |
1380 | let mut last_kv = node.last_kv(); | |
1381 | ||
1382 | if last_kv.can_merge() { | |
1383 | cur_node = last_kv.merge().descend(); | |
1384 | } else { | |
1385 | let right_len = last_kv.reborrow().right_edge().descend().len(); | |
1386 | // `MINLEN + 1` to avoid readjust if merge happens on the next level. | |
1387 | if right_len < node::MIN_LEN + 1 { | |
1388 | last_kv.bulk_steal_left(node::MIN_LEN + 1 - right_len); | |
1389 | } | |
1390 | cur_node = last_kv.right_edge().descend(); | |
1391 | } | |
1392 | } | |
1393 | } | |
1394 | ||
1395 | self.fix_top(); | |
1396 | } | |
1397 | ||
1398 | /// The symmetric clone of `fix_right_border`. | |
1399 | fn fix_left_border(&mut self) { | |
1400 | self.fix_top(); | |
1401 | ||
1402 | { | |
ba9703b0 | 1403 | let mut cur_node = self.root.as_mut().unwrap().as_mut(); |
3157f602 XL |
1404 | |
1405 | while let Internal(node) = cur_node.force() { | |
1406 | let mut first_kv = node.first_kv(); | |
1407 | ||
1408 | if first_kv.can_merge() { | |
1409 | cur_node = first_kv.merge().descend(); | |
1410 | } else { | |
1411 | let left_len = first_kv.reborrow().left_edge().descend().len(); | |
1412 | if left_len < node::MIN_LEN + 1 { | |
1413 | first_kv.bulk_steal_right(node::MIN_LEN + 1 - left_len); | |
1414 | } | |
1415 | cur_node = first_kv.left_edge().descend(); | |
1416 | } | |
1417 | } | |
1418 | } | |
1419 | ||
1420 | self.fix_top(); | |
1421 | } | |
85aaf69f SL |
1422 | } |
1423 | ||
c30ab7b3 | 1424 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 1425 | impl<'a, K: 'a, V: 'a> IntoIterator for &'a BTreeMap<K, V> { |
85aaf69f SL |
1426 | type Item = (&'a K, &'a V); |
1427 | type IntoIter = Iter<'a, K, V>; | |
1428 | ||
1429 | fn into_iter(self) -> Iter<'a, K, V> { | |
1430 | self.iter() | |
1431 | } | |
1432 | } | |
1433 | ||
c30ab7b3 | 1434 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1435 | impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> { |
1436 | type Item = (&'a K, &'a V); | |
85aaf69f | 1437 | |
9cc50fc6 SL |
1438 | fn next(&mut self) -> Option<(&'a K, &'a V)> { |
1439 | if self.length == 0 { | |
1440 | None | |
1441 | } else { | |
1442 | self.length -= 1; | |
1443 | unsafe { Some(self.range.next_unchecked()) } | |
1444 | } | |
85aaf69f | 1445 | } |
85aaf69f | 1446 | |
9cc50fc6 SL |
1447 | fn size_hint(&self) -> (usize, Option<usize>) { |
1448 | (self.length, Some(self.length)) | |
1449 | } | |
416331ca XL |
1450 | |
1451 | fn last(mut self) -> Option<(&'a K, &'a V)> { | |
1452 | self.next_back() | |
1453 | } | |
1a4d82fc JJ |
1454 | } |
1455 | ||
0531ce1d | 1456 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1457 | impl<K, V> FusedIterator for Iter<'_, K, V> {} |
9e0c209e | 1458 | |
c30ab7b3 | 1459 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1460 | impl<'a, K: 'a, V: 'a> DoubleEndedIterator for Iter<'a, K, V> { |
1461 | fn next_back(&mut self) -> Option<(&'a K, &'a V)> { | |
1462 | if self.length == 0 { | |
1463 | None | |
1464 | } else { | |
1465 | self.length -= 1; | |
1466 | unsafe { Some(self.range.next_back_unchecked()) } | |
85aaf69f SL |
1467 | } |
1468 | } | |
9cc50fc6 | 1469 | } |
85aaf69f | 1470 | |
c30ab7b3 | 1471 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1472 | impl<K, V> ExactSizeIterator for Iter<'_, K, V> { |
3157f602 XL |
1473 | fn len(&self) -> usize { |
1474 | self.length | |
1475 | } | |
9cc50fc6 | 1476 | } |
1a4d82fc | 1477 | |
c30ab7b3 | 1478 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 XL |
1479 | impl<K, V> Clone for Iter<'_, K, V> { |
1480 | fn clone(&self) -> Self { | |
dfeec247 | 1481 | Iter { range: self.range.clone(), length: self.length } |
1a4d82fc | 1482 | } |
9cc50fc6 | 1483 | } |
1a4d82fc | 1484 | |
c30ab7b3 | 1485 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1486 | impl<'a, K: 'a, V: 'a> IntoIterator for &'a mut BTreeMap<K, V> { |
1487 | type Item = (&'a K, &'a mut V); | |
1488 | type IntoIter = IterMut<'a, K, V>; | |
1489 | ||
1490 | fn into_iter(self) -> IterMut<'a, K, V> { | |
1491 | self.iter_mut() | |
1a4d82fc | 1492 | } |
9cc50fc6 | 1493 | } |
1a4d82fc | 1494 | |
c30ab7b3 | 1495 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1496 | impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> { |
1497 | type Item = (&'a K, &'a mut V); | |
1a4d82fc | 1498 | |
9cc50fc6 SL |
1499 | fn next(&mut self) -> Option<(&'a K, &'a mut V)> { |
1500 | if self.length == 0 { | |
1501 | None | |
1502 | } else { | |
1503 | self.length -= 1; | |
74b04a01 XL |
1504 | let (k, v) = unsafe { self.range.next_unchecked() }; |
1505 | Some((k, v)) // coerce k from `&mut K` to `&K` | |
9cc50fc6 | 1506 | } |
1a4d82fc JJ |
1507 | } |
1508 | ||
9cc50fc6 SL |
1509 | fn size_hint(&self) -> (usize, Option<usize>) { |
1510 | (self.length, Some(self.length)) | |
1a4d82fc | 1511 | } |
416331ca XL |
1512 | |
1513 | fn last(mut self) -> Option<(&'a K, &'a mut V)> { | |
1514 | self.next_back() | |
1515 | } | |
9cc50fc6 | 1516 | } |
1a4d82fc | 1517 | |
c30ab7b3 | 1518 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1519 | impl<'a, K: 'a, V: 'a> DoubleEndedIterator for IterMut<'a, K, V> { |
1520 | fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> { | |
1521 | if self.length == 0 { | |
1522 | None | |
1523 | } else { | |
1524 | self.length -= 1; | |
74b04a01 XL |
1525 | let (k, v) = unsafe { self.range.next_back_unchecked() }; |
1526 | Some((k, v)) // coerce k from `&mut K` to `&K` | |
9cc50fc6 | 1527 | } |
1a4d82fc | 1528 | } |
9cc50fc6 | 1529 | } |
1a4d82fc | 1530 | |
c30ab7b3 | 1531 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1532 | impl<K, V> ExactSizeIterator for IterMut<'_, K, V> { |
3157f602 XL |
1533 | fn len(&self) -> usize { |
1534 | self.length | |
1535 | } | |
9cc50fc6 | 1536 | } |
1a4d82fc | 1537 | |
0531ce1d | 1538 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1539 | impl<K, V> FusedIterator for IterMut<'_, K, V> {} |
9e0c209e | 1540 | |
c30ab7b3 | 1541 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1542 | impl<K, V> IntoIterator for BTreeMap<K, V> { |
1543 | type Item = (K, V); | |
1544 | type IntoIter = IntoIter<K, V>; | |
1a4d82fc | 1545 | |
9cc50fc6 | 1546 | fn into_iter(self) -> IntoIter<K, V> { |
ba9703b0 XL |
1547 | let mut me = ManuallyDrop::new(self); |
1548 | if let Some(root) = me.root.as_mut() { | |
1549 | let root1 = unsafe { ptr::read(root).into_ref() }; | |
1550 | let root2 = unsafe { ptr::read(root).into_ref() }; | |
1551 | let len = me.length; | |
1552 | ||
1553 | IntoIter { | |
1554 | front: Some(root1.first_leaf_edge()), | |
1555 | back: Some(root2.last_leaf_edge()), | |
1556 | length: len, | |
1557 | } | |
1558 | } else { | |
1559 | IntoIter { front: None, back: None, length: 0 } | |
1560 | } | |
1a4d82fc | 1561 | } |
9cc50fc6 | 1562 | } |
1a4d82fc | 1563 | |
c30ab7b3 | 1564 | #[stable(feature = "btree_drop", since = "1.7.0")] |
9cc50fc6 SL |
1565 | impl<K, V> Drop for IntoIter<K, V> { |
1566 | fn drop(&mut self) { | |
74b04a01 XL |
1567 | struct DropGuard<'a, K, V>(&'a mut IntoIter<K, V>); |
1568 | ||
1569 | impl<'a, K, V> Drop for DropGuard<'a, K, V> { | |
1570 | fn drop(&mut self) { | |
1571 | // Continue the same loop we perform below. This only runs when unwinding, so we | |
1572 | // don't have to care about panics this time (they'll abort). | |
1573 | while let Some(_) = self.0.next() {} | |
1574 | ||
74b04a01 | 1575 | unsafe { |
ba9703b0 XL |
1576 | let mut node = |
1577 | unwrap_unchecked(ptr::read(&self.0.front)).into_node().forget_type(); | |
74b04a01 XL |
1578 | while let Some(parent) = node.deallocate_and_ascend() { |
1579 | node = parent.into_node().forget_type(); | |
1580 | } | |
1581 | } | |
1582 | } | |
1583 | } | |
1584 | ||
1585 | while let Some(pair) = self.next() { | |
1586 | let guard = DropGuard(self); | |
1587 | drop(pair); | |
1588 | mem::forget(guard); | |
1589 | } | |
1590 | ||
9cc50fc6 | 1591 | unsafe { |
ba9703b0 XL |
1592 | if let Some(front) = ptr::read(&self.front) { |
1593 | let mut node = front.into_node().forget_type(); | |
1594 | // Most of the nodes have been deallocated while traversing | |
1595 | // but one pile from a leaf up to the root is left standing. | |
1596 | while let Some(parent) = node.deallocate_and_ascend() { | |
1597 | node = parent.into_node().forget_type(); | |
1598 | } | |
1a4d82fc JJ |
1599 | } |
1600 | } | |
1601 | } | |
9cc50fc6 | 1602 | } |
1a4d82fc | 1603 | |
c30ab7b3 | 1604 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1605 | impl<K, V> Iterator for IntoIter<K, V> { |
1606 | type Item = (K, V); | |
1a4d82fc | 1607 | |
9cc50fc6 SL |
1608 | fn next(&mut self) -> Option<(K, V)> { |
1609 | if self.length == 0 { | |
74b04a01 | 1610 | None |
9cc50fc6 SL |
1611 | } else { |
1612 | self.length -= 1; | |
ba9703b0 | 1613 | Some(unsafe { self.front.as_mut().unwrap().next_unchecked() }) |
1a4d82fc JJ |
1614 | } |
1615 | } | |
1616 | ||
9cc50fc6 SL |
1617 | fn size_hint(&self) -> (usize, Option<usize>) { |
1618 | (self.length, Some(self.length)) | |
1619 | } | |
1620 | } | |
1621 | ||
c30ab7b3 | 1622 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1623 | impl<K, V> DoubleEndedIterator for IntoIter<K, V> { |
1624 | fn next_back(&mut self) -> Option<(K, V)> { | |
1625 | if self.length == 0 { | |
74b04a01 | 1626 | None |
9cc50fc6 SL |
1627 | } else { |
1628 | self.length -= 1; | |
ba9703b0 | 1629 | Some(unsafe { self.back.as_mut().unwrap().next_back_unchecked() }) |
1a4d82fc JJ |
1630 | } |
1631 | } | |
1632 | } | |
1633 | ||
c30ab7b3 | 1634 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 1635 | impl<K, V> ExactSizeIterator for IntoIter<K, V> { |
3157f602 XL |
1636 | fn len(&self) -> usize { |
1637 | self.length | |
1638 | } | |
1a4d82fc JJ |
1639 | } |
1640 | ||
0531ce1d | 1641 | #[stable(feature = "fused", since = "1.26.0")] |
9e0c209e SL |
1642 | impl<K, V> FusedIterator for IntoIter<K, V> {} |
1643 | ||
c30ab7b3 | 1644 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1645 | impl<'a, K, V> Iterator for Keys<'a, K, V> { |
1646 | type Item = &'a K; | |
1647 | ||
1648 | fn next(&mut self) -> Option<&'a K> { | |
1649 | self.inner.next().map(|(k, _)| k) | |
1a4d82fc | 1650 | } |
1a4d82fc | 1651 | |
9cc50fc6 SL |
1652 | fn size_hint(&self) -> (usize, Option<usize>) { |
1653 | self.inner.size_hint() | |
62682a34 | 1654 | } |
416331ca XL |
1655 | |
1656 | fn last(mut self) -> Option<&'a K> { | |
1657 | self.next_back() | |
1658 | } | |
62682a34 SL |
1659 | } |
1660 | ||
c30ab7b3 | 1661 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1662 | impl<'a, K, V> DoubleEndedIterator for Keys<'a, K, V> { |
1663 | fn next_back(&mut self) -> Option<&'a K> { | |
1664 | self.inner.next_back().map(|(k, _)| k) | |
1a4d82fc JJ |
1665 | } |
1666 | } | |
1667 | ||
c30ab7b3 | 1668 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1669 | impl<K, V> ExactSizeIterator for Keys<'_, K, V> { |
9cc50fc6 SL |
1670 | fn len(&self) -> usize { |
1671 | self.inner.len() | |
1a4d82fc JJ |
1672 | } |
1673 | } | |
1674 | ||
0531ce1d | 1675 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1676 | impl<K, V> FusedIterator for Keys<'_, K, V> {} |
9e0c209e | 1677 | |
c30ab7b3 | 1678 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 XL |
1679 | impl<K, V> Clone for Keys<'_, K, V> { |
1680 | fn clone(&self) -> Self { | |
3157f602 | 1681 | Keys { inner: self.inner.clone() } |
1a4d82fc JJ |
1682 | } |
1683 | } | |
1684 | ||
c30ab7b3 | 1685 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1686 | impl<'a, K, V> Iterator for Values<'a, K, V> { |
1687 | type Item = &'a V; | |
1a4d82fc | 1688 | |
9cc50fc6 SL |
1689 | fn next(&mut self) -> Option<&'a V> { |
1690 | self.inner.next().map(|(_, v)| v) | |
1a4d82fc | 1691 | } |
1a4d82fc | 1692 | |
9cc50fc6 SL |
1693 | fn size_hint(&self) -> (usize, Option<usize>) { |
1694 | self.inner.size_hint() | |
1a4d82fc | 1695 | } |
416331ca XL |
1696 | |
1697 | fn last(mut self) -> Option<&'a V> { | |
1698 | self.next_back() | |
1699 | } | |
1a4d82fc JJ |
1700 | } |
1701 | ||
c30ab7b3 | 1702 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1703 | impl<'a, K, V> DoubleEndedIterator for Values<'a, K, V> { |
1704 | fn next_back(&mut self) -> Option<&'a V> { | |
1705 | self.inner.next_back().map(|(_, v)| v) | |
1a4d82fc JJ |
1706 | } |
1707 | } | |
1708 | ||
c30ab7b3 | 1709 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1710 | impl<K, V> ExactSizeIterator for Values<'_, K, V> { |
9cc50fc6 SL |
1711 | fn len(&self) -> usize { |
1712 | self.inner.len() | |
1a4d82fc JJ |
1713 | } |
1714 | } | |
1715 | ||
0531ce1d | 1716 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1717 | impl<K, V> FusedIterator for Values<'_, K, V> {} |
9e0c209e | 1718 | |
c30ab7b3 | 1719 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 XL |
1720 | impl<K, V> Clone for Values<'_, K, V> { |
1721 | fn clone(&self) -> Self { | |
3157f602 | 1722 | Values { inner: self.inner.clone() } |
1a4d82fc JJ |
1723 | } |
1724 | } | |
1725 | ||
ba9703b0 XL |
1726 | /// An iterator produced by calling `drain_filter` on BTreeMap. |
1727 | #[unstable(feature = "btree_drain_filter", issue = "70530")] | |
1728 | pub struct DrainFilter<'a, K, V, F> | |
1729 | where | |
1730 | K: 'a, | |
1731 | V: 'a, | |
1732 | F: 'a + FnMut(&K, &mut V) -> bool, | |
1733 | { | |
1734 | pred: F, | |
1735 | inner: DrainFilterInner<'a, K, V>, | |
1736 | } | |
1737 | pub(super) struct DrainFilterInner<'a, K: 'a, V: 'a> { | |
1738 | length: &'a mut usize, | |
1739 | cur_leaf_edge: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>, | |
1740 | } | |
1741 | ||
1742 | #[unstable(feature = "btree_drain_filter", issue = "70530")] | |
1743 | impl<K, V, F> Drop for DrainFilter<'_, K, V, F> | |
1744 | where | |
1745 | F: FnMut(&K, &mut V) -> bool, | |
1746 | { | |
1747 | fn drop(&mut self) { | |
1748 | self.for_each(drop); | |
1749 | } | |
1750 | } | |
1751 | ||
1752 | #[unstable(feature = "btree_drain_filter", issue = "70530")] | |
1753 | impl<K, V, F> fmt::Debug for DrainFilter<'_, K, V, F> | |
1754 | where | |
1755 | K: fmt::Debug, | |
1756 | V: fmt::Debug, | |
1757 | F: FnMut(&K, &mut V) -> bool, | |
1758 | { | |
1759 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1760 | f.debug_tuple("DrainFilter").field(&self.inner.peek()).finish() | |
1761 | } | |
1762 | } | |
1763 | ||
1764 | #[unstable(feature = "btree_drain_filter", issue = "70530")] | |
1765 | impl<K, V, F> Iterator for DrainFilter<'_, K, V, F> | |
1766 | where | |
1767 | F: FnMut(&K, &mut V) -> bool, | |
1768 | { | |
1769 | type Item = (K, V); | |
1770 | ||
1771 | fn next(&mut self) -> Option<(K, V)> { | |
1772 | self.inner.next(&mut self.pred) | |
1773 | } | |
1774 | ||
1775 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1776 | self.inner.size_hint() | |
1777 | } | |
1778 | } | |
1779 | ||
1780 | impl<'a, K: 'a, V: 'a> DrainFilterInner<'a, K, V> { | |
1781 | /// Allow Debug implementations to predict the next element. | |
1782 | pub(super) fn peek(&self) -> Option<(&K, &V)> { | |
1783 | let edge = self.cur_leaf_edge.as_ref()?; | |
1784 | edge.reborrow().next_kv().ok().map(|kv| kv.into_kv()) | |
1785 | } | |
1786 | ||
1787 | unsafe fn next_kv( | |
1788 | &mut self, | |
1789 | ) -> Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::KV>> { | |
1790 | let edge = self.cur_leaf_edge.as_ref()?; | |
1791 | ptr::read(edge).next_kv().ok() | |
1792 | } | |
1793 | ||
1794 | /// Implementation of a typical `DrainFilter::next` method, given the predicate. | |
1795 | pub(super) fn next<F>(&mut self, pred: &mut F) -> Option<(K, V)> | |
1796 | where | |
1797 | F: FnMut(&K, &mut V) -> bool, | |
1798 | { | |
1799 | while let Some(mut kv) = unsafe { self.next_kv() } { | |
1800 | let (k, v) = kv.kv_mut(); | |
1801 | if pred(k, v) { | |
1802 | *self.length -= 1; | |
1803 | let (k, v, leaf_edge_location) = kv.remove_kv_tracking(); | |
1804 | self.cur_leaf_edge = Some(leaf_edge_location); | |
1805 | return Some((k, v)); | |
1806 | } | |
1807 | self.cur_leaf_edge = Some(kv.next_leaf_edge()); | |
1808 | } | |
1809 | None | |
1810 | } | |
1811 | ||
1812 | /// Implementation of a typical `DrainFilter::size_hint` method. | |
1813 | pub(super) fn size_hint(&self) -> (usize, Option<usize>) { | |
1814 | (0, Some(*self.length)) | |
1815 | } | |
1816 | } | |
1817 | ||
1818 | #[unstable(feature = "btree_drain_filter", issue = "70530")] | |
1819 | impl<K, V, F> FusedIterator for DrainFilter<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {} | |
1820 | ||
cc61c64b | 1821 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 SL |
1822 | impl<'a, K, V> Iterator for Range<'a, K, V> { |
1823 | type Item = (&'a K, &'a V); | |
1a4d82fc | 1824 | |
9cc50fc6 | 1825 | fn next(&mut self) -> Option<(&'a K, &'a V)> { |
74b04a01 | 1826 | if self.is_empty() { None } else { unsafe { Some(self.next_unchecked()) } } |
1a4d82fc | 1827 | } |
416331ca XL |
1828 | |
1829 | fn last(mut self) -> Option<(&'a K, &'a V)> { | |
1830 | self.next_back() | |
1831 | } | |
1a4d82fc JJ |
1832 | } |
1833 | ||
a7813a04 | 1834 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
54a0048b SL |
1835 | impl<'a, K, V> Iterator for ValuesMut<'a, K, V> { |
1836 | type Item = &'a mut V; | |
1837 | ||
1838 | fn next(&mut self) -> Option<&'a mut V> { | |
1839 | self.inner.next().map(|(_, v)| v) | |
1840 | } | |
1841 | ||
1842 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1843 | self.inner.size_hint() | |
1844 | } | |
416331ca XL |
1845 | |
1846 | fn last(mut self) -> Option<&'a mut V> { | |
1847 | self.next_back() | |
1848 | } | |
54a0048b SL |
1849 | } |
1850 | ||
a7813a04 | 1851 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
54a0048b SL |
1852 | impl<'a, K, V> DoubleEndedIterator for ValuesMut<'a, K, V> { |
1853 | fn next_back(&mut self) -> Option<&'a mut V> { | |
1854 | self.inner.next_back().map(|(_, v)| v) | |
1855 | } | |
1856 | } | |
1857 | ||
a7813a04 | 1858 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
9fa01778 | 1859 | impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> { |
54a0048b SL |
1860 | fn len(&self) -> usize { |
1861 | self.inner.len() | |
1862 | } | |
1863 | } | |
1864 | ||
0531ce1d | 1865 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1866 | impl<K, V> FusedIterator for ValuesMut<'_, K, V> {} |
9e0c209e | 1867 | |
9cc50fc6 | 1868 | impl<'a, K, V> Range<'a, K, V> { |
74b04a01 XL |
1869 | fn is_empty(&self) -> bool { |
1870 | self.front == self.back | |
1871 | } | |
1a4d82fc | 1872 | |
74b04a01 | 1873 | unsafe fn next_unchecked(&mut self) -> (&'a K, &'a V) { |
ba9703b0 | 1874 | unwrap_unchecked(self.front.as_mut()).next_unchecked() |
1a4d82fc | 1875 | } |
9cc50fc6 | 1876 | } |
1a4d82fc | 1877 | |
cc61c64b | 1878 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 SL |
1879 | impl<'a, K, V> DoubleEndedIterator for Range<'a, K, V> { |
1880 | fn next_back(&mut self) -> Option<(&'a K, &'a V)> { | |
74b04a01 | 1881 | if self.is_empty() { None } else { Some(unsafe { self.next_back_unchecked() }) } |
1a4d82fc JJ |
1882 | } |
1883 | } | |
1884 | ||
9cc50fc6 SL |
1885 | impl<'a, K, V> Range<'a, K, V> { |
1886 | unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a V) { | |
ba9703b0 | 1887 | unwrap_unchecked(self.back.as_mut()).next_back_unchecked() |
1a4d82fc JJ |
1888 | } |
1889 | } | |
1890 | ||
0531ce1d | 1891 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1892 | impl<K, V> FusedIterator for Range<'_, K, V> {} |
9e0c209e | 1893 | |
cc61c64b | 1894 | #[stable(feature = "btree_range", since = "1.17.0")] |
9fa01778 XL |
1895 | impl<K, V> Clone for Range<'_, K, V> { |
1896 | fn clone(&self) -> Self { | |
dfeec247 | 1897 | Range { front: self.front, back: self.back } |
92a42be0 | 1898 | } |
1a4d82fc | 1899 | } |
1a4d82fc | 1900 | |
cc61c64b | 1901 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 | 1902 | impl<'a, K, V> Iterator for RangeMut<'a, K, V> { |
1a4d82fc JJ |
1903 | type Item = (&'a K, &'a mut V); |
1904 | ||
92a42be0 | 1905 | fn next(&mut self) -> Option<(&'a K, &'a mut V)> { |
74b04a01 XL |
1906 | if self.is_empty() { |
1907 | None | |
1908 | } else { | |
1909 | let (k, v) = unsafe { self.next_unchecked() }; | |
1910 | Some((k, v)) // coerce k from `&mut K` to `&K` | |
1911 | } | |
92a42be0 | 1912 | } |
416331ca XL |
1913 | |
1914 | fn last(mut self) -> Option<(&'a K, &'a mut V)> { | |
1915 | self.next_back() | |
1916 | } | |
1a4d82fc | 1917 | } |
1a4d82fc | 1918 | |
9cc50fc6 | 1919 | impl<'a, K, V> RangeMut<'a, K, V> { |
74b04a01 XL |
1920 | fn is_empty(&self) -> bool { |
1921 | self.front == self.back | |
1922 | } | |
1a4d82fc | 1923 | |
74b04a01 | 1924 | unsafe fn next_unchecked(&mut self) -> (&'a mut K, &'a mut V) { |
ba9703b0 | 1925 | unwrap_unchecked(self.front.as_mut()).next_unchecked() |
92a42be0 | 1926 | } |
c34b1796 | 1927 | } |
1a4d82fc | 1928 | |
cc61c64b | 1929 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 SL |
1930 | impl<'a, K, V> DoubleEndedIterator for RangeMut<'a, K, V> { |
1931 | fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> { | |
74b04a01 XL |
1932 | if self.is_empty() { |
1933 | None | |
1934 | } else { | |
1935 | let (k, v) = unsafe { self.next_back_unchecked() }; | |
1936 | Some((k, v)) // coerce k from `&mut K` to `&K` | |
1937 | } | |
92a42be0 | 1938 | } |
1a4d82fc | 1939 | } |
1a4d82fc | 1940 | |
0531ce1d | 1941 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1942 | impl<K, V> FusedIterator for RangeMut<'_, K, V> {} |
9e0c209e | 1943 | |
9cc50fc6 | 1944 | impl<'a, K, V> RangeMut<'a, K, V> { |
74b04a01 | 1945 | unsafe fn next_back_unchecked(&mut self) -> (&'a mut K, &'a mut V) { |
ba9703b0 | 1946 | unwrap_unchecked(self.back.as_mut()).next_back_unchecked() |
92a42be0 | 1947 | } |
1a4d82fc | 1948 | } |
9cc50fc6 | 1949 | |
c30ab7b3 | 1950 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 1951 | impl<K: Ord, V> FromIterator<(K, V)> for BTreeMap<K, V> { |
3157f602 | 1952 | fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> BTreeMap<K, V> { |
9cc50fc6 SL |
1953 | let mut map = BTreeMap::new(); |
1954 | map.extend(iter); | |
1955 | map | |
92a42be0 | 1956 | } |
1a4d82fc | 1957 | } |
1a4d82fc | 1958 | |
c30ab7b3 | 1959 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1960 | impl<K: Ord, V> Extend<(K, V)> for BTreeMap<K, V> { |
1961 | #[inline] | |
3157f602 | 1962 | fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T) { |
532ac7d7 | 1963 | iter.into_iter().for_each(move |(k, v)| { |
9cc50fc6 | 1964 | self.insert(k, v); |
532ac7d7 | 1965 | }); |
92a42be0 | 1966 | } |
c34b1796 | 1967 | } |
85aaf69f | 1968 | |
c30ab7b3 | 1969 | #[stable(feature = "extend_ref", since = "1.2.0")] |
9cc50fc6 | 1970 | impl<'a, K: Ord + Copy, V: Copy> Extend<(&'a K, &'a V)> for BTreeMap<K, V> { |
3157f602 | 1971 | fn extend<I: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iter: I) { |
9cc50fc6 | 1972 | self.extend(iter.into_iter().map(|(&key, &value)| (key, value))); |
92a42be0 | 1973 | } |
85aaf69f | 1974 | } |
9cc50fc6 | 1975 | |
c30ab7b3 | 1976 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1977 | impl<K: Hash, V: Hash> Hash for BTreeMap<K, V> { |
1978 | fn hash<H: Hasher>(&self, state: &mut H) { | |
1979 | for elt in self { | |
1980 | elt.hash(state); | |
1981 | } | |
92a42be0 | 1982 | } |
85aaf69f SL |
1983 | } |
1984 | ||
c30ab7b3 | 1985 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 1986 | impl<K: Ord, V> Default for BTreeMap<K, V> { |
9e0c209e | 1987 | /// Creates an empty `BTreeMap<K, V>`. |
9cc50fc6 SL |
1988 | fn default() -> BTreeMap<K, V> { |
1989 | BTreeMap::new() | |
92a42be0 | 1990 | } |
85aaf69f | 1991 | } |
9cc50fc6 | 1992 | |
c30ab7b3 | 1993 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1994 | impl<K: PartialEq, V: PartialEq> PartialEq for BTreeMap<K, V> { |
1995 | fn eq(&self, other: &BTreeMap<K, V>) -> bool { | |
3157f602 | 1996 | self.len() == other.len() && self.iter().zip(other).all(|(a, b)| a == b) |
92a42be0 | 1997 | } |
85aaf69f SL |
1998 | } |
1999 | ||
c30ab7b3 | 2000 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 2001 | impl<K: Eq, V: Eq> Eq for BTreeMap<K, V> {} |
c34b1796 | 2002 | |
c30ab7b3 | 2003 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
2004 | impl<K: PartialOrd, V: PartialOrd> PartialOrd for BTreeMap<K, V> { |
2005 | #[inline] | |
2006 | fn partial_cmp(&self, other: &BTreeMap<K, V>) -> Option<Ordering> { | |
2007 | self.iter().partial_cmp(other.iter()) | |
c34b1796 | 2008 | } |
1a4d82fc JJ |
2009 | } |
2010 | ||
c30ab7b3 | 2011 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
2012 | impl<K: Ord, V: Ord> Ord for BTreeMap<K, V> { |
2013 | #[inline] | |
2014 | fn cmp(&self, other: &BTreeMap<K, V>) -> Ordering { | |
2015 | self.iter().cmp(other.iter()) | |
1a4d82fc JJ |
2016 | } |
2017 | } | |
2018 | ||
c30ab7b3 | 2019 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 2020 | impl<K: Debug, V: Debug> Debug for BTreeMap<K, V> { |
9fa01778 | 2021 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
9cc50fc6 | 2022 | f.debug_map().entries(self.iter()).finish() |
1a4d82fc | 2023 | } |
9cc50fc6 | 2024 | } |
1a4d82fc | 2025 | |
c30ab7b3 | 2026 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 2027 | impl<K: Ord, Q: ?Sized, V> Index<&Q> for BTreeMap<K, V> |
dfeec247 XL |
2028 | where |
2029 | K: Borrow<Q>, | |
2030 | Q: Ord, | |
9cc50fc6 SL |
2031 | { |
2032 | type Output = V; | |
1a4d82fc | 2033 | |
2c00a5a8 XL |
2034 | /// Returns a reference to the value corresponding to the supplied key. |
2035 | /// | |
2036 | /// # Panics | |
2037 | /// | |
2038 | /// Panics if the key is not present in the `BTreeMap`. | |
9cc50fc6 SL |
2039 | #[inline] |
2040 | fn index(&self, key: &Q) -> &V { | |
2041 | self.get(key).expect("no entry found for key") | |
1a4d82fc | 2042 | } |
9cc50fc6 | 2043 | } |
1a4d82fc | 2044 | |
0531ce1d | 2045 | fn range_search<BorrowType, K, V, Q: ?Sized, R: RangeBounds<Q>>( |
8bb4bdeb XL |
2046 | root1: NodeRef<BorrowType, K, V, marker::LeafOrInternal>, |
2047 | root2: NodeRef<BorrowType, K, V, marker::LeafOrInternal>, | |
dfeec247 XL |
2048 | range: R, |
2049 | ) -> ( | |
2050 | Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge>, | |
2051 | Handle<NodeRef<BorrowType, K, V, marker::Leaf>, marker::Edge>, | |
2052 | ) | |
2053 | where | |
2054 | Q: Ord, | |
2055 | K: Borrow<Q>, | |
8bb4bdeb | 2056 | { |
94b46f34 | 2057 | match (range.start_bound(), range.end_bound()) { |
dfeec247 XL |
2058 | (Excluded(s), Excluded(e)) if s == e => { |
2059 | panic!("range start and end are equal and excluded in BTreeMap") | |
2060 | } | |
ba9703b0 | 2061 | (Included(s) | Excluded(s), Included(e) | Excluded(e)) if s > e => { |
dfeec247 XL |
2062 | panic!("range start is greater than range end in BTreeMap") |
2063 | } | |
2064 | _ => {} | |
8bb4bdeb XL |
2065 | }; |
2066 | ||
2067 | let mut min_node = root1; | |
2068 | let mut max_node = root2; | |
2069 | let mut min_found = false; | |
2070 | let mut max_found = false; | |
8bb4bdeb XL |
2071 | |
2072 | loop { | |
74b04a01 XL |
2073 | let front = match (min_found, range.start_bound()) { |
2074 | (false, Included(key)) => match search::search_node(min_node, key) { | |
2075 | Found(kv) => { | |
dfeec247 | 2076 | min_found = true; |
74b04a01 | 2077 | kv.left_edge() |
dfeec247 | 2078 | } |
74b04a01 | 2079 | GoDown(edge) => edge, |
8bb4bdeb | 2080 | }, |
74b04a01 XL |
2081 | (false, Excluded(key)) => match search::search_node(min_node, key) { |
2082 | Found(kv) => { | |
dfeec247 | 2083 | min_found = true; |
74b04a01 | 2084 | kv.right_edge() |
dfeec247 | 2085 | } |
74b04a01 | 2086 | GoDown(edge) => edge, |
8bb4bdeb | 2087 | }, |
74b04a01 XL |
2088 | (true, Included(_)) => min_node.last_edge(), |
2089 | (true, Excluded(_)) => min_node.first_edge(), | |
2090 | (_, Unbounded) => min_node.first_edge(), | |
8bb4bdeb XL |
2091 | }; |
2092 | ||
74b04a01 XL |
2093 | let back = match (max_found, range.end_bound()) { |
2094 | (false, Included(key)) => match search::search_node(max_node, key) { | |
2095 | Found(kv) => { | |
dfeec247 | 2096 | max_found = true; |
74b04a01 | 2097 | kv.right_edge() |
dfeec247 | 2098 | } |
74b04a01 | 2099 | GoDown(edge) => edge, |
8bb4bdeb | 2100 | }, |
74b04a01 XL |
2101 | (false, Excluded(key)) => match search::search_node(max_node, key) { |
2102 | Found(kv) => { | |
dfeec247 | 2103 | max_found = true; |
74b04a01 | 2104 | kv.left_edge() |
dfeec247 | 2105 | } |
74b04a01 | 2106 | GoDown(edge) => edge, |
8bb4bdeb | 2107 | }, |
74b04a01 XL |
2108 | (true, Included(_)) => max_node.first_edge(), |
2109 | (true, Excluded(_)) => max_node.last_edge(), | |
2110 | (_, Unbounded) => max_node.last_edge(), | |
8bb4bdeb XL |
2111 | }; |
2112 | ||
74b04a01 XL |
2113 | if front.partial_cmp(&back) == Some(Ordering::Greater) { |
2114 | panic!("Ord is ill-defined in BTreeMap range"); | |
8bb4bdeb | 2115 | } |
8bb4bdeb XL |
2116 | match (front.force(), back.force()) { |
2117 | (Leaf(f), Leaf(b)) => { | |
2118 | return (f, b); | |
dfeec247 | 2119 | } |
8bb4bdeb XL |
2120 | (Internal(min_int), Internal(max_int)) => { |
2121 | min_node = min_int.descend(); | |
2122 | max_node = max_int.descend(); | |
dfeec247 | 2123 | } |
8bb4bdeb XL |
2124 | _ => unreachable!("BTreeMap has different depths"), |
2125 | }; | |
2126 | } | |
2127 | } | |
2128 | ||
1a4d82fc | 2129 | impl<K, V> BTreeMap<K, V> { |
7453a54e | 2130 | /// Gets an iterator over the entries of the map, sorted by key. |
1a4d82fc | 2131 | /// |
c34b1796 | 2132 | /// # Examples |
1a4d82fc | 2133 | /// |
54a0048b SL |
2134 | /// Basic usage: |
2135 | /// | |
1a4d82fc JJ |
2136 | /// ``` |
2137 | /// use std::collections::BTreeMap; | |
2138 | /// | |
2139 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 2140 | /// map.insert(3, "c"); |
7453a54e SL |
2141 | /// map.insert(2, "b"); |
2142 | /// map.insert(1, "a"); | |
1a4d82fc JJ |
2143 | /// |
2144 | /// for (key, value) in map.iter() { | |
2145 | /// println!("{}: {}", key, value); | |
2146 | /// } | |
2147 | /// | |
2148 | /// let (first_key, first_value) = map.iter().next().unwrap(); | |
85aaf69f | 2149 | /// assert_eq!((*first_key, *first_value), (1, "a")); |
1a4d82fc | 2150 | /// ``` |
85aaf69f | 2151 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 2152 | pub fn iter(&self) -> Iter<'_, K, V> { |
1a4d82fc | 2153 | Iter { |
9cc50fc6 | 2154 | range: Range { |
ba9703b0 XL |
2155 | front: self.root.as_ref().map(|r| r.as_ref().first_leaf_edge()), |
2156 | back: self.root.as_ref().map(|r| r.as_ref().last_leaf_edge()), | |
92a42be0 | 2157 | }, |
3157f602 | 2158 | length: self.length, |
1a4d82fc JJ |
2159 | } |
2160 | } | |
2161 | ||
7453a54e | 2162 | /// Gets a mutable iterator over the entries of the map, sorted by key. |
1a4d82fc JJ |
2163 | /// |
2164 | /// # Examples | |
2165 | /// | |
54a0048b SL |
2166 | /// Basic usage: |
2167 | /// | |
1a4d82fc JJ |
2168 | /// ``` |
2169 | /// use std::collections::BTreeMap; | |
2170 | /// | |
2171 | /// let mut map = BTreeMap::new(); | |
85aaf69f SL |
2172 | /// map.insert("a", 1); |
2173 | /// map.insert("b", 2); | |
2174 | /// map.insert("c", 3); | |
1a4d82fc JJ |
2175 | /// |
2176 | /// // add 10 to the value if the key isn't "a" | |
2177 | /// for (key, value) in map.iter_mut() { | |
2178 | /// if key != &"a" { | |
2179 | /// *value += 10; | |
2180 | /// } | |
2181 | /// } | |
2182 | /// ``` | |
85aaf69f | 2183 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 2184 | pub fn iter_mut(&mut self) -> IterMut<'_, K, V> { |
1a4d82fc | 2185 | IterMut { |
ba9703b0 XL |
2186 | range: if let Some(root) = &mut self.root { |
2187 | let root1 = root.as_mut(); | |
2188 | let root2 = unsafe { ptr::read(&root1) }; | |
2189 | RangeMut { | |
2190 | front: Some(root1.first_leaf_edge()), | |
2191 | back: Some(root2.last_leaf_edge()), | |
2192 | _marker: PhantomData, | |
2193 | } | |
2194 | } else { | |
2195 | RangeMut { front: None, back: None, _marker: PhantomData } | |
92a42be0 | 2196 | }, |
3157f602 | 2197 | length: self.length, |
1a4d82fc JJ |
2198 | } |
2199 | } | |
2200 | ||
7453a54e | 2201 | /// Gets an iterator over the keys of the map, in sorted order. |
1a4d82fc JJ |
2202 | /// |
2203 | /// # Examples | |
2204 | /// | |
54a0048b SL |
2205 | /// Basic usage: |
2206 | /// | |
1a4d82fc JJ |
2207 | /// ``` |
2208 | /// use std::collections::BTreeMap; | |
2209 | /// | |
2210 | /// let mut a = BTreeMap::new(); | |
85aaf69f | 2211 | /// a.insert(2, "b"); |
7453a54e | 2212 | /// a.insert(1, "a"); |
1a4d82fc | 2213 | /// |
62682a34 | 2214 | /// let keys: Vec<_> = a.keys().cloned().collect(); |
c34b1796 | 2215 | /// assert_eq!(keys, [1, 2]); |
1a4d82fc | 2216 | /// ``` |
85aaf69f | 2217 | #[stable(feature = "rust1", since = "1.0.0")] |
416331ca | 2218 | pub fn keys(&self) -> Keys<'_, K, V> { |
9cc50fc6 | 2219 | Keys { inner: self.iter() } |
1a4d82fc JJ |
2220 | } |
2221 | ||
7453a54e | 2222 | /// Gets an iterator over the values of the map, in order by key. |
1a4d82fc JJ |
2223 | /// |
2224 | /// # Examples | |
2225 | /// | |
54a0048b SL |
2226 | /// Basic usage: |
2227 | /// | |
1a4d82fc JJ |
2228 | /// ``` |
2229 | /// use std::collections::BTreeMap; | |
2230 | /// | |
2231 | /// let mut a = BTreeMap::new(); | |
7453a54e SL |
2232 | /// a.insert(1, "hello"); |
2233 | /// a.insert(2, "goodbye"); | |
1a4d82fc JJ |
2234 | /// |
2235 | /// let values: Vec<&str> = a.values().cloned().collect(); | |
7453a54e | 2236 | /// assert_eq!(values, ["hello", "goodbye"]); |
1a4d82fc | 2237 | /// ``` |
85aaf69f | 2238 | #[stable(feature = "rust1", since = "1.0.0")] |
416331ca | 2239 | pub fn values(&self) -> Values<'_, K, V> { |
9cc50fc6 | 2240 | Values { inner: self.iter() } |
1a4d82fc JJ |
2241 | } |
2242 | ||
54a0048b SL |
2243 | /// Gets a mutable iterator over the values of the map, in order by key. |
2244 | /// | |
2245 | /// # Examples | |
2246 | /// | |
2247 | /// Basic usage: | |
2248 | /// | |
2249 | /// ``` | |
54a0048b SL |
2250 | /// use std::collections::BTreeMap; |
2251 | /// | |
2252 | /// let mut a = BTreeMap::new(); | |
2253 | /// a.insert(1, String::from("hello")); | |
2254 | /// a.insert(2, String::from("goodbye")); | |
2255 | /// | |
2256 | /// for value in a.values_mut() { | |
2257 | /// value.push_str("!"); | |
2258 | /// } | |
2259 | /// | |
2260 | /// let values: Vec<String> = a.values().cloned().collect(); | |
2261 | /// assert_eq!(values, [String::from("hello!"), | |
2262 | /// String::from("goodbye!")]); | |
2263 | /// ``` | |
a7813a04 | 2264 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
9fa01778 | 2265 | pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> { |
54a0048b SL |
2266 | ValuesMut { inner: self.iter_mut() } |
2267 | } | |
2268 | ||
9346a6ac | 2269 | /// Returns the number of elements in the map. |
1a4d82fc JJ |
2270 | /// |
2271 | /// # Examples | |
2272 | /// | |
54a0048b SL |
2273 | /// Basic usage: |
2274 | /// | |
1a4d82fc JJ |
2275 | /// ``` |
2276 | /// use std::collections::BTreeMap; | |
2277 | /// | |
2278 | /// let mut a = BTreeMap::new(); | |
2279 | /// assert_eq!(a.len(), 0); | |
85aaf69f | 2280 | /// a.insert(1, "a"); |
1a4d82fc JJ |
2281 | /// assert_eq!(a.len(), 1); |
2282 | /// ``` | |
85aaf69f | 2283 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 SL |
2284 | pub fn len(&self) -> usize { |
2285 | self.length | |
2286 | } | |
1a4d82fc | 2287 | |
cc61c64b | 2288 | /// Returns `true` if the map contains no elements. |
1a4d82fc JJ |
2289 | /// |
2290 | /// # Examples | |
2291 | /// | |
54a0048b SL |
2292 | /// Basic usage: |
2293 | /// | |
1a4d82fc JJ |
2294 | /// ``` |
2295 | /// use std::collections::BTreeMap; | |
2296 | /// | |
2297 | /// let mut a = BTreeMap::new(); | |
2298 | /// assert!(a.is_empty()); | |
85aaf69f | 2299 | /// a.insert(1, "a"); |
1a4d82fc JJ |
2300 | /// assert!(!a.is_empty()); |
2301 | /// ``` | |
85aaf69f | 2302 | #[stable(feature = "rust1", since = "1.0.0")] |
92a42be0 SL |
2303 | pub fn is_empty(&self) -> bool { |
2304 | self.len() == 0 | |
2305 | } | |
ba9703b0 XL |
2306 | |
2307 | /// If the root node is the empty (non-allocated) root node, allocate our | |
2308 | /// own node. | |
2309 | fn ensure_root_is_owned(&mut self) -> &mut node::Root<K, V> { | |
2310 | self.root.get_or_insert_with(node::Root::new_leaf) | |
2311 | } | |
1a4d82fc JJ |
2312 | } |
2313 | ||
9cc50fc6 SL |
2314 | impl<'a, K: Ord, V> Entry<'a, K, V> { |
2315 | /// Ensures a value is in the entry by inserting the default if empty, and returns | |
2316 | /// a mutable reference to the value in the entry. | |
5bcae85e SL |
2317 | /// |
2318 | /// # Examples | |
2319 | /// | |
2320 | /// ``` | |
2321 | /// use std::collections::BTreeMap; | |
2322 | /// | |
2323 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2324 | /// map.entry("poneyland").or_insert(12); | |
2325 | /// | |
2326 | /// assert_eq!(map["poneyland"], 12); | |
2327 | /// ``` | |
9cc50fc6 SL |
2328 | #[stable(feature = "rust1", since = "1.0.0")] |
2329 | pub fn or_insert(self, default: V) -> &'a mut V { | |
2330 | match self { | |
2331 | Occupied(entry) => entry.into_mut(), | |
2332 | Vacant(entry) => entry.insert(default), | |
2333 | } | |
2334 | } | |
85aaf69f | 2335 | |
9cc50fc6 SL |
2336 | /// Ensures a value is in the entry by inserting the result of the default function if empty, |
2337 | /// and returns a mutable reference to the value in the entry. | |
5bcae85e SL |
2338 | /// |
2339 | /// # Examples | |
2340 | /// | |
2341 | /// ``` | |
2342 | /// use std::collections::BTreeMap; | |
2343 | /// | |
2344 | /// let mut map: BTreeMap<&str, String> = BTreeMap::new(); | |
32a655c1 | 2345 | /// let s = "hoho".to_string(); |
5bcae85e SL |
2346 | /// |
2347 | /// map.entry("poneyland").or_insert_with(|| s); | |
2348 | /// | |
32a655c1 | 2349 | /// assert_eq!(map["poneyland"], "hoho".to_string()); |
5bcae85e | 2350 | /// ``` |
9cc50fc6 SL |
2351 | #[stable(feature = "rust1", since = "1.0.0")] |
2352 | pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V { | |
2353 | match self { | |
2354 | Occupied(entry) => entry.into_mut(), | |
2355 | Vacant(entry) => entry.insert(default()), | |
2356 | } | |
2357 | } | |
a7813a04 | 2358 | |
ba9703b0 XL |
2359 | #[unstable(feature = "or_insert_with_key", issue = "71024")] |
2360 | /// Ensures a value is in the entry by inserting, if empty, the result of the default function, | |
2361 | /// which takes the key as its argument, and returns a mutable reference to the value in the | |
2362 | /// entry. | |
2363 | /// | |
2364 | /// # Examples | |
2365 | /// | |
2366 | /// ``` | |
2367 | /// #![feature(or_insert_with_key)] | |
2368 | /// use std::collections::BTreeMap; | |
2369 | /// | |
2370 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2371 | /// | |
2372 | /// map.entry("poneyland").or_insert_with_key(|key| key.chars().count()); | |
2373 | /// | |
2374 | /// assert_eq!(map["poneyland"], 9); | |
2375 | /// ``` | |
2376 | #[inline] | |
2377 | pub fn or_insert_with_key<F: FnOnce(&K) -> V>(self, default: F) -> &'a mut V { | |
2378 | match self { | |
2379 | Occupied(entry) => entry.into_mut(), | |
2380 | Vacant(entry) => { | |
2381 | let value = default(entry.key()); | |
2382 | entry.insert(value) | |
2383 | } | |
2384 | } | |
2385 | } | |
2386 | ||
a7813a04 | 2387 | /// Returns a reference to this entry's key. |
5bcae85e SL |
2388 | /// |
2389 | /// # Examples | |
2390 | /// | |
2391 | /// ``` | |
2392 | /// use std::collections::BTreeMap; | |
2393 | /// | |
2394 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2395 | /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); | |
2396 | /// ``` | |
a7813a04 XL |
2397 | #[stable(feature = "map_entry_keys", since = "1.10.0")] |
2398 | pub fn key(&self) -> &K { | |
2399 | match *self { | |
2400 | Occupied(ref entry) => entry.key(), | |
2401 | Vacant(ref entry) => entry.key(), | |
2402 | } | |
2403 | } | |
ea8adc8c XL |
2404 | |
2405 | /// Provides in-place mutable access to an occupied entry before any | |
2406 | /// potential inserts into the map. | |
2407 | /// | |
2408 | /// # Examples | |
2409 | /// | |
2410 | /// ``` | |
ea8adc8c XL |
2411 | /// use std::collections::BTreeMap; |
2412 | /// | |
2413 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2414 | /// | |
2415 | /// map.entry("poneyland") | |
2416 | /// .and_modify(|e| { *e += 1 }) | |
2417 | /// .or_insert(42); | |
2418 | /// assert_eq!(map["poneyland"], 42); | |
2419 | /// | |
2420 | /// map.entry("poneyland") | |
2421 | /// .and_modify(|e| { *e += 1 }) | |
2422 | /// .or_insert(42); | |
2423 | /// assert_eq!(map["poneyland"], 43); | |
2424 | /// ``` | |
0531ce1d XL |
2425 | #[stable(feature = "entry_and_modify", since = "1.26.0")] |
2426 | pub fn and_modify<F>(self, f: F) -> Self | |
dfeec247 XL |
2427 | where |
2428 | F: FnOnce(&mut V), | |
ea8adc8c XL |
2429 | { |
2430 | match self { | |
2431 | Occupied(mut entry) => { | |
2432 | f(entry.get_mut()); | |
2433 | Occupied(entry) | |
dfeec247 | 2434 | } |
ea8adc8c XL |
2435 | Vacant(entry) => Vacant(entry), |
2436 | } | |
2437 | } | |
2438 | } | |
2439 | ||
2440 | impl<'a, K: Ord, V: Default> Entry<'a, K, V> { | |
94b46f34 | 2441 | #[stable(feature = "entry_or_default", since = "1.28.0")] |
ea8adc8c XL |
2442 | /// Ensures a value is in the entry by inserting the default value if empty, |
2443 | /// and returns a mutable reference to the value in the entry. | |
2444 | /// | |
2445 | /// # Examples | |
2446 | /// | |
2447 | /// ``` | |
ea8adc8c XL |
2448 | /// use std::collections::BTreeMap; |
2449 | /// | |
2450 | /// let mut map: BTreeMap<&str, Option<usize>> = BTreeMap::new(); | |
2451 | /// map.entry("poneyland").or_default(); | |
2452 | /// | |
2453 | /// assert_eq!(map["poneyland"], None); | |
ea8adc8c XL |
2454 | /// ``` |
2455 | pub fn or_default(self) -> &'a mut V { | |
2456 | match self { | |
2457 | Occupied(entry) => entry.into_mut(), | |
2458 | Vacant(entry) => entry.insert(Default::default()), | |
2459 | } | |
2460 | } | |
9cc50fc6 | 2461 | } |
85aaf69f | 2462 | |
9cc50fc6 | 2463 | impl<'a, K: Ord, V> VacantEntry<'a, K, V> { |
54a0048b SL |
2464 | /// Gets a reference to the key that would be used when inserting a value |
2465 | /// through the VacantEntry. | |
5bcae85e SL |
2466 | /// |
2467 | /// # Examples | |
2468 | /// | |
2469 | /// ``` | |
2470 | /// use std::collections::BTreeMap; | |
2471 | /// | |
2472 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2473 | /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); | |
2474 | /// ``` | |
a7813a04 | 2475 | #[stable(feature = "map_entry_keys", since = "1.10.0")] |
54a0048b SL |
2476 | pub fn key(&self) -> &K { |
2477 | &self.key | |
2478 | } | |
2479 | ||
3157f602 | 2480 | /// Take ownership of the key. |
5bcae85e SL |
2481 | /// |
2482 | /// # Examples | |
2483 | /// | |
2484 | /// ``` | |
2485 | /// use std::collections::BTreeMap; | |
2486 | /// use std::collections::btree_map::Entry; | |
2487 | /// | |
2488 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2489 | /// | |
2490 | /// if let Entry::Vacant(v) = map.entry("poneyland") { | |
2491 | /// v.into_key(); | |
2492 | /// } | |
2493 | /// ``` | |
2494 | #[stable(feature = "map_entry_recover_keys2", since = "1.12.0")] | |
3157f602 XL |
2495 | pub fn into_key(self) -> K { |
2496 | self.key | |
2497 | } | |
2498 | ||
9e0c209e | 2499 | /// Sets the value of the entry with the `VacantEntry`'s key, |
9cc50fc6 | 2500 | /// and returns a mutable reference to it. |
5bcae85e SL |
2501 | /// |
2502 | /// # Examples | |
2503 | /// | |
2504 | /// ``` | |
2505 | /// use std::collections::BTreeMap; | |
2506 | /// | |
2507 | /// let mut count: BTreeMap<&str, usize> = BTreeMap::new(); | |
2508 | /// | |
2509 | /// // count the number of occurrences of letters in the vec | |
2510 | /// for x in vec!["a","b","a","c","a","b"] { | |
2511 | /// *count.entry(x).or_insert(0) += 1; | |
2512 | /// } | |
2513 | /// | |
2514 | /// assert_eq!(count["a"], 3); | |
2515 | /// ``` | |
9cc50fc6 SL |
2516 | #[stable(feature = "rust1", since = "1.0.0")] |
2517 | pub fn insert(self, value: V) -> &'a mut V { | |
2518 | *self.length += 1; | |
2519 | ||
2520 | let out_ptr; | |
2521 | ||
2522 | let mut ins_k; | |
2523 | let mut ins_v; | |
2524 | let mut ins_edge; | |
2525 | ||
2526 | let mut cur_parent = match self.handle.insert(self.key, value) { | |
2527 | (Fit(handle), _) => return handle.into_kv_mut().1, | |
2528 | (Split(left, k, v, right), ptr) => { | |
2529 | ins_k = k; | |
2530 | ins_v = v; | |
2531 | ins_edge = right; | |
2532 | out_ptr = ptr; | |
2533 | left.ascend().map_err(|n| n.into_root_mut()) | |
85aaf69f | 2534 | } |
9cc50fc6 | 2535 | }; |
85aaf69f | 2536 | |
9cc50fc6 SL |
2537 | loop { |
2538 | match cur_parent { | |
dfeec247 XL |
2539 | Ok(parent) => match parent.insert(ins_k, ins_v, ins_edge) { |
2540 | Fit(_) => return unsafe { &mut *out_ptr }, | |
2541 | Split(left, k, v, right) => { | |
2542 | ins_k = k; | |
2543 | ins_v = v; | |
2544 | ins_edge = right; | |
2545 | cur_parent = left.ascend().map_err(|n| n.into_root_mut()); | |
9cc50fc6 | 2546 | } |
dfeec247 | 2547 | }, |
9cc50fc6 SL |
2548 | Err(root) => { |
2549 | root.push_level().push(ins_k, ins_v, ins_edge); | |
2550 | return unsafe { &mut *out_ptr }; | |
85aaf69f SL |
2551 | } |
2552 | } | |
2553 | } | |
9cc50fc6 | 2554 | } |
85aaf69f SL |
2555 | } |
2556 | ||
9cc50fc6 | 2557 | impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> { |
54a0048b | 2558 | /// Gets a reference to the key in the entry. |
5bcae85e SL |
2559 | /// |
2560 | /// # Examples | |
2561 | /// | |
2562 | /// ``` | |
2563 | /// use std::collections::BTreeMap; | |
2564 | /// | |
2565 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2566 | /// map.entry("poneyland").or_insert(12); | |
2567 | /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); | |
2568 | /// ``` | |
a7813a04 | 2569 | #[stable(feature = "map_entry_keys", since = "1.10.0")] |
54a0048b SL |
2570 | pub fn key(&self) -> &K { |
2571 | self.handle.reborrow().into_kv().0 | |
2572 | } | |
2573 | ||
5bcae85e SL |
2574 | /// Take ownership of the key and value from the map. |
2575 | /// | |
2576 | /// # Examples | |
2577 | /// | |
2578 | /// ``` | |
2579 | /// use std::collections::BTreeMap; | |
2580 | /// use std::collections::btree_map::Entry; | |
2581 | /// | |
2582 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2583 | /// map.entry("poneyland").or_insert(12); | |
2584 | /// | |
2585 | /// if let Entry::Occupied(o) = map.entry("poneyland") { | |
2586 | /// // We delete the entry from the map. | |
2587 | /// o.remove_entry(); | |
2588 | /// } | |
2589 | /// | |
2590 | /// // If now try to get the value, it will panic: | |
2591 | /// // println!("{}", map["poneyland"]); | |
2592 | /// ``` | |
2593 | #[stable(feature = "map_entry_recover_keys2", since = "1.12.0")] | |
2594 | pub fn remove_entry(self) -> (K, V) { | |
3157f602 XL |
2595 | self.remove_kv() |
2596 | } | |
2597 | ||
9cc50fc6 | 2598 | /// Gets a reference to the value in the entry. |
5bcae85e SL |
2599 | /// |
2600 | /// # Examples | |
2601 | /// | |
2602 | /// ``` | |
2603 | /// use std::collections::BTreeMap; | |
2604 | /// use std::collections::btree_map::Entry; | |
2605 | /// | |
2606 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2607 | /// map.entry("poneyland").or_insert(12); | |
2608 | /// | |
2609 | /// if let Entry::Occupied(o) = map.entry("poneyland") { | |
2610 | /// assert_eq!(o.get(), &12); | |
2611 | /// } | |
2612 | /// ``` | |
9cc50fc6 SL |
2613 | #[stable(feature = "rust1", since = "1.0.0")] |
2614 | pub fn get(&self) -> &V { | |
2615 | self.handle.reborrow().into_kv().1 | |
85aaf69f SL |
2616 | } |
2617 | ||
9cc50fc6 | 2618 | /// Gets a mutable reference to the value in the entry. |
5bcae85e | 2619 | /// |
9fa01778 | 2620 | /// If you need a reference to the `OccupiedEntry` that may outlive the |
94b46f34 XL |
2621 | /// destruction of the `Entry` value, see [`into_mut`]. |
2622 | /// | |
2623 | /// [`into_mut`]: #method.into_mut | |
2624 | /// | |
5bcae85e SL |
2625 | /// # Examples |
2626 | /// | |
2627 | /// ``` | |
2628 | /// use std::collections::BTreeMap; | |
2629 | /// use std::collections::btree_map::Entry; | |
2630 | /// | |
2631 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2632 | /// map.entry("poneyland").or_insert(12); | |
2633 | /// | |
2634 | /// assert_eq!(map["poneyland"], 12); | |
2635 | /// if let Entry::Occupied(mut o) = map.entry("poneyland") { | |
94b46f34 XL |
2636 | /// *o.get_mut() += 10; |
2637 | /// assert_eq!(*o.get(), 22); | |
2638 | /// | |
2639 | /// // We can use the same Entry multiple times. | |
2640 | /// *o.get_mut() += 2; | |
5bcae85e | 2641 | /// } |
94b46f34 | 2642 | /// assert_eq!(map["poneyland"], 24); |
5bcae85e | 2643 | /// ``` |
9cc50fc6 SL |
2644 | #[stable(feature = "rust1", since = "1.0.0")] |
2645 | pub fn get_mut(&mut self) -> &mut V { | |
2646 | self.handle.kv_mut().1 | |
85aaf69f SL |
2647 | } |
2648 | ||
9cc50fc6 | 2649 | /// Converts the entry into a mutable reference to its value. |
5bcae85e | 2650 | /// |
94b46f34 XL |
2651 | /// If you need multiple references to the `OccupiedEntry`, see [`get_mut`]. |
2652 | /// | |
2653 | /// [`get_mut`]: #method.get_mut | |
2654 | /// | |
5bcae85e SL |
2655 | /// # Examples |
2656 | /// | |
2657 | /// ``` | |
2658 | /// use std::collections::BTreeMap; | |
2659 | /// use std::collections::btree_map::Entry; | |
2660 | /// | |
2661 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2662 | /// map.entry("poneyland").or_insert(12); | |
2663 | /// | |
2664 | /// assert_eq!(map["poneyland"], 12); | |
2665 | /// if let Entry::Occupied(o) = map.entry("poneyland") { | |
2666 | /// *o.into_mut() += 10; | |
2667 | /// } | |
2668 | /// assert_eq!(map["poneyland"], 22); | |
2669 | /// ``` | |
85aaf69f | 2670 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
2671 | pub fn into_mut(self) -> &'a mut V { |
2672 | self.handle.into_kv_mut().1 | |
1a4d82fc | 2673 | } |
e9174d1e | 2674 | |
9e0c209e | 2675 | /// Sets the value of the entry with the `OccupiedEntry`'s key, |
9cc50fc6 | 2676 | /// and returns the entry's old value. |
5bcae85e SL |
2677 | /// |
2678 | /// # Examples | |
2679 | /// | |
2680 | /// ``` | |
2681 | /// use std::collections::BTreeMap; | |
2682 | /// use std::collections::btree_map::Entry; | |
2683 | /// | |
2684 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2685 | /// map.entry("poneyland").or_insert(12); | |
2686 | /// | |
2687 | /// if let Entry::Occupied(mut o) = map.entry("poneyland") { | |
2688 | /// assert_eq!(o.insert(15), 12); | |
2689 | /// } | |
2690 | /// assert_eq!(map["poneyland"], 15); | |
2691 | /// ``` | |
9cc50fc6 SL |
2692 | #[stable(feature = "rust1", since = "1.0.0")] |
2693 | pub fn insert(&mut self, value: V) -> V { | |
2694 | mem::replace(self.get_mut(), value) | |
2695 | } | |
e9174d1e | 2696 | |
9cc50fc6 | 2697 | /// Takes the value of the entry out of the map, and returns it. |
5bcae85e SL |
2698 | /// |
2699 | /// # Examples | |
2700 | /// | |
2701 | /// ``` | |
2702 | /// use std::collections::BTreeMap; | |
2703 | /// use std::collections::btree_map::Entry; | |
2704 | /// | |
2705 | /// let mut map: BTreeMap<&str, usize> = BTreeMap::new(); | |
2706 | /// map.entry("poneyland").or_insert(12); | |
2707 | /// | |
2708 | /// if let Entry::Occupied(o) = map.entry("poneyland") { | |
2709 | /// assert_eq!(o.remove(), 12); | |
2710 | /// } | |
2711 | /// // If we try to get "poneyland"'s value, it'll panic: | |
2712 | /// // println!("{}", map["poneyland"]); | |
2713 | /// ``` | |
9cc50fc6 SL |
2714 | #[stable(feature = "rust1", since = "1.0.0")] |
2715 | pub fn remove(self) -> V { | |
2716 | self.remove_kv().1 | |
e9174d1e SL |
2717 | } |
2718 | ||
9cc50fc6 SL |
2719 | fn remove_kv(self) -> (K, V) { |
2720 | *self.length -= 1; | |
e9174d1e | 2721 | |
ba9703b0 XL |
2722 | let (old_key, old_val, _) = self.handle.remove_kv_tracking(); |
2723 | (old_key, old_val) | |
2724 | } | |
2725 | } | |
2726 | ||
2727 | impl<'a, K: 'a, V: 'a> Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::KV> { | |
2728 | /// Removes a key/value-pair from the map, and returns that pair, as well as | |
2729 | /// the leaf edge corresponding to that former pair. | |
2730 | fn remove_kv_tracking( | |
2731 | self, | |
2732 | ) -> (K, V, Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>) { | |
2733 | let (mut pos, old_key, old_val, was_internal) = match self.force() { | |
9cc50fc6 SL |
2734 | Leaf(leaf) => { |
2735 | let (hole, old_key, old_val) = leaf.remove(); | |
ba9703b0 | 2736 | (hole, old_key, old_val, false) |
3157f602 | 2737 | } |
9cc50fc6 | 2738 | Internal(mut internal) => { |
ba9703b0 XL |
2739 | // Replace the location freed in the internal node with the next KV, |
2740 | // and remove that next KV from its leaf. | |
2741 | ||
9cc50fc6 SL |
2742 | let key_loc = internal.kv_mut().0 as *mut K; |
2743 | let val_loc = internal.kv_mut().1 as *mut V; | |
2744 | ||
ba9703b0 XL |
2745 | // Deleting from the left side is typically faster since we can |
2746 | // just pop an element from the end of the KV array without | |
2747 | // needing to shift the other values. | |
2748 | let to_remove = internal.left_edge().descend().last_leaf_edge().left_kv().ok(); | |
9cc50fc6 SL |
2749 | let to_remove = unsafe { unwrap_unchecked(to_remove) }; |
2750 | ||
2751 | let (hole, key, val) = to_remove.remove(); | |
2752 | ||
3157f602 XL |
2753 | let old_key = unsafe { mem::replace(&mut *key_loc, key) }; |
2754 | let old_val = unsafe { mem::replace(&mut *val_loc, val) }; | |
9cc50fc6 | 2755 | |
ba9703b0 | 2756 | (hole, old_key, old_val, true) |
9cc50fc6 SL |
2757 | } |
2758 | }; | |
2759 | ||
2760 | // Handle underflow | |
ba9703b0 XL |
2761 | let mut cur_node = unsafe { ptr::read(&pos).into_node().forget_type() }; |
2762 | let mut at_leaf = true; | |
dfeec247 | 2763 | while cur_node.len() < node::MIN_LEN { |
9cc50fc6 SL |
2764 | match handle_underfull_node(cur_node) { |
2765 | AtRoot => break, | |
ba9703b0 XL |
2766 | Merged(edge, merged_with_left, offset) => { |
2767 | // If we merged with our right sibling then our tracked | |
2768 | // position has not changed. However if we merged with our | |
2769 | // left sibling then our tracked position is now dangling. | |
2770 | if at_leaf && merged_with_left { | |
2771 | let idx = pos.idx() + offset; | |
2772 | let node = match unsafe { ptr::read(&edge).descend().force() } { | |
2773 | Leaf(leaf) => leaf, | |
2774 | Internal(_) => unreachable!(), | |
2775 | }; | |
2776 | pos = unsafe { Handle::new_edge(node, idx) }; | |
2777 | } | |
2778 | ||
2779 | let parent = edge.into_node(); | |
3157f602 XL |
2780 | if parent.len() == 0 { |
2781 | // We must be at the root | |
2782 | parent.into_root_mut().pop_level(); | |
2783 | break; | |
2784 | } else { | |
2785 | cur_node = parent.forget_type(); | |
ba9703b0 | 2786 | at_leaf = false; |
3157f602 XL |
2787 | } |
2788 | } | |
ba9703b0 XL |
2789 | Stole(stole_from_left) => { |
2790 | // Adjust the tracked position if we stole from a left sibling | |
2791 | if stole_from_left && at_leaf { | |
2792 | // SAFETY: This is safe since we just added an element to our node. | |
2793 | unsafe { | |
2794 | pos.next_unchecked(); | |
2795 | } | |
2796 | } | |
2797 | break; | |
2798 | } | |
e9174d1e SL |
2799 | } |
2800 | } | |
9cc50fc6 | 2801 | |
ba9703b0 XL |
2802 | // If we deleted from an internal node then we need to compensate for |
2803 | // the earlier swap and adjust the tracked position to point to the | |
2804 | // next element. | |
2805 | if was_internal { | |
2806 | pos = unsafe { unwrap_unchecked(pos.next_kv().ok()).next_leaf_edge() }; | |
2807 | } | |
2808 | ||
2809 | (old_key, old_val, pos) | |
e9174d1e | 2810 | } |
9cc50fc6 | 2811 | } |
e9174d1e | 2812 | |
9cc50fc6 SL |
2813 | enum UnderflowResult<'a, K, V> { |
2814 | AtRoot, | |
ba9703b0 XL |
2815 | Merged(Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::Edge>, bool, usize), |
2816 | Stole(bool), | |
9cc50fc6 SL |
2817 | } |
2818 | ||
dfeec247 XL |
2819 | fn handle_underfull_node<K, V>( |
2820 | node: NodeRef<marker::Mut<'_>, K, V, marker::LeafOrInternal>, | |
2821 | ) -> UnderflowResult<'_, K, V> { | |
ba9703b0 XL |
2822 | let parent = match node.ascend() { |
2823 | Ok(parent) => parent, | |
2824 | Err(_) => return AtRoot, | |
9cc50fc6 SL |
2825 | }; |
2826 | ||
2827 | let (is_left, mut handle) = match parent.left_kv() { | |
2828 | Ok(left) => (true, left), | |
ba9703b0 XL |
2829 | Err(parent) => { |
2830 | let right = unsafe { unwrap_unchecked(parent.right_kv().ok()) }; | |
2831 | (false, right) | |
2832 | } | |
9cc50fc6 SL |
2833 | }; |
2834 | ||
2835 | if handle.can_merge() { | |
ba9703b0 XL |
2836 | let offset = if is_left { handle.reborrow().left_edge().descend().len() + 1 } else { 0 }; |
2837 | Merged(handle.merge(), is_left, offset) | |
9cc50fc6 | 2838 | } else { |
a7813a04 XL |
2839 | if is_left { |
2840 | handle.steal_left(); | |
2841 | } else { | |
2842 | handle.steal_right(); | |
2843 | } | |
ba9703b0 | 2844 | Stole(is_left) |
a7813a04 XL |
2845 | } |
2846 | } | |
e9174d1e | 2847 | |
3157f602 | 2848 | impl<K: Ord, V, I: Iterator<Item = (K, V)>> Iterator for MergeIter<K, V, I> { |
a7813a04 | 2849 | type Item = (K, V); |
e9174d1e | 2850 | |
a7813a04 XL |
2851 | fn next(&mut self) -> Option<(K, V)> { |
2852 | let res = match (self.left.peek(), self.right.peek()) { | |
2853 | (Some(&(ref left_key, _)), Some(&(ref right_key, _))) => left_key.cmp(right_key), | |
2854 | (Some(_), None) => Ordering::Less, | |
2855 | (None, Some(_)) => Ordering::Greater, | |
2856 | (None, None) => return None, | |
2857 | }; | |
9cc50fc6 | 2858 | |
a7813a04 XL |
2859 | // Check which elements comes first and only advance the corresponding iterator. |
2860 | // If two keys are equal, take the value from `right`. | |
2861 | match res { | |
3157f602 XL |
2862 | Ordering::Less => self.left.next(), |
2863 | Ordering::Greater => self.right.next(), | |
a7813a04 XL |
2864 | Ordering::Equal => { |
2865 | self.left.next(); | |
2866 | self.right.next() | |
3157f602 | 2867 | } |
a7813a04 | 2868 | } |
e9174d1e SL |
2869 | } |
2870 | } |