]>
Commit | Line | Data |
---|---|---|
c295e0f8 | 1 | use crate::vec::Vec; |
9fa01778 | 2 | use core::borrow::Borrow; |
1a4d82fc | 3 | use core::cmp::Ordering; |
3dfed10e | 4 | use core::fmt::{self, Debug}; |
1a4d82fc | 5 | use core::hash::{Hash, Hasher}; |
353b0b11 | 6 | use core::iter::FusedIterator; |
9cc50fc6 | 7 | use core::marker::PhantomData; |
ba9703b0 | 8 | use core::mem::{self, ManuallyDrop}; |
9ffffee4 | 9 | use core::ops::{Bound, Index, RangeBounds}; |
3dfed10e | 10 | use core::ptr; |
1a4d82fc | 11 | |
923072b8 FG |
12 | use crate::alloc::{Allocator, Global}; |
13 | ||
1b1a35ee | 14 | use super::borrow::DormantMutRef; |
c295e0f8 | 15 | use super::dedup_sorted_iter::DedupSortedIter; |
94222f64 | 16 | use super::navigate::{LazyLeafRange, LeafRange}; |
fc512014 | 17 | use super::node::{self, marker, ForceResult::*, Handle, NodeRef, Root}; |
9ffffee4 | 18 | use super::search::{SearchBound, SearchResult::*}; |
923072b8 | 19 | use super::set_val::SetValZST; |
9cc50fc6 | 20 | |
29967ef6 | 21 | mod entry; |
5099ac24 FG |
22 | |
23 | #[stable(feature = "rust1", since = "1.0.0")] | |
6a06907d | 24 | pub use entry::{Entry, OccupiedEntry, OccupiedError, VacantEntry}; |
5099ac24 | 25 | |
9fa01778 | 26 | use Entry::*; |
29967ef6 | 27 | |
c295e0f8 | 28 | /// Minimum number of elements in a node that is not a root. |
29967ef6 XL |
29 | /// We might temporarily have fewer elements during methods. |
30 | pub(super) const MIN_LEN: usize = node::MIN_LEN_AFTER_SPLIT; | |
1a4d82fc | 31 | |
6a06907d XL |
32 | // A tree in a `BTreeMap` is a tree in the `node` module with additional invariants: |
33 | // - Keys must appear in ascending order (according to the key's type). | |
c295e0f8 | 34 | // - Every non-leaf node contains at least 1 element (has at least 2 children). |
6a06907d XL |
35 | // - Every non-root node contains at least MIN_LEN elements. |
36 | // | |
c295e0f8 | 37 | // An empty map is represented either by the absence of a root node or by a |
6a06907d XL |
38 | // root node that is an empty leaf. |
39 | ||
5099ac24 | 40 | /// An ordered map based on a [B-Tree]. |
1a4d82fc JJ |
41 | /// |
42 | /// B-Trees represent a fundamental compromise between cache-efficiency and actually minimizing | |
43 | /// the amount of work performed in a search. In theory, a binary search tree (BST) is the optimal | |
44 | /// choice for a sorted map, as a perfectly balanced BST performs the theoretical minimum amount of | |
45 | /// comparisons necessary to find an element (log<sub>2</sub>n). However, in practice the way this | |
46 | /// is done is *very* inefficient for modern computer architectures. In particular, every element | |
47 | /// is stored in its own individually heap-allocated node. This means that every single insertion | |
48 | /// triggers a heap-allocation, and every single comparison should be a cache-miss. Since these | |
487cf647 FG |
49 | /// are both notably expensive things to do in practice, we are forced to, at the very least, |
50 | /// reconsider the BST strategy. | |
1a4d82fc JJ |
51 | /// |
52 | /// A B-Tree instead makes each node contain B-1 to 2B-1 elements in a contiguous array. By doing | |
53 | /// this, we reduce the number of allocations by a factor of B, and improve cache efficiency in | |
54 | /// searches. However, this does mean that searches will have to do *more* comparisons on average. | |
55 | /// The precise number of comparisons depends on the node search strategy used. For optimal cache | |
56 | /// efficiency, one could search the nodes linearly. For optimal comparisons, one could search | |
57 | /// the node using binary search. As a compromise, one could also perform a linear search | |
58 | /// that initially only checks every i<sup>th</sup> element for some choice of i. | |
59 | /// | |
60 | /// Currently, our implementation simply performs naive linear search. This provides excellent | |
61 | /// performance on *small* nodes of elements which are cheap to compare. However in the future we | |
62 | /// would like to further explore choosing the optimal search strategy based on the choice of B, | |
63 | /// and possibly other factors. Using linear search, searching for a random element is expected | |
3c0e092e | 64 | /// to take B * log(n) comparisons, which is generally worse than a BST. In practice, |
85aaf69f | 65 | /// however, performance is excellent. |
c34b1796 AL |
66 | /// |
67 | /// It is a logic error for a key to be modified in such a way that the key's ordering relative to | |
9e0c209e SL |
68 | /// any other key, as determined by the [`Ord`] trait, changes while it is in the map. This is |
69 | /// normally only possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code. | |
923072b8 FG |
70 | /// The behavior resulting from such a logic error is not specified, but will be encapsulated to the |
71 | /// `BTreeMap` that observed the logic error and not result in undefined behavior. This could | |
72 | /// include panics, incorrect results, aborts, memory leaks, and non-termination. | |
9e0c209e | 73 | /// |
5099ac24 FG |
74 | /// Iterators obtained from functions such as [`BTreeMap::iter`], [`BTreeMap::values`], or |
75 | /// [`BTreeMap::keys`] produce their items in order by key, and take worst-case logarithmic and | |
76 | /// amortized constant time per item returned. | |
77 | /// | |
6a06907d | 78 | /// [B-Tree]: https://en.wikipedia.org/wiki/B-tree |
3dfed10e XL |
79 | /// [`Cell`]: core::cell::Cell |
80 | /// [`RefCell`]: core::cell::RefCell | |
54a0048b SL |
81 | /// |
82 | /// # Examples | |
83 | /// | |
84 | /// ``` | |
85 | /// use std::collections::BTreeMap; | |
86 | /// | |
87 | /// // type inference lets us omit an explicit type signature (which | |
88 | /// // would be `BTreeMap<&str, &str>` in this example). | |
89 | /// let mut movie_reviews = BTreeMap::new(); | |
90 | /// | |
3157f602 | 91 | /// // review some movies. |
54a0048b SL |
92 | /// movie_reviews.insert("Office Space", "Deals with real issues in the workplace."); |
93 | /// movie_reviews.insert("Pulp Fiction", "Masterpiece."); | |
94 | /// movie_reviews.insert("The Godfather", "Very enjoyable."); | |
0bf4aa26 | 95 | /// movie_reviews.insert("The Blues Brothers", "Eye lyked it a lot."); |
54a0048b SL |
96 | /// |
97 | /// // check for a specific one. | |
98 | /// if !movie_reviews.contains_key("Les Misérables") { | |
99 | /// println!("We've got {} reviews, but Les Misérables ain't one.", | |
100 | /// movie_reviews.len()); | |
101 | /// } | |
102 | /// | |
103 | /// // oops, this review has a lot of spelling mistakes, let's delete it. | |
104 | /// movie_reviews.remove("The Blues Brothers"); | |
105 | /// | |
106 | /// // look up the values associated with some keys. | |
107 | /// let to_find = ["Up!", "Office Space"]; | |
416331ca XL |
108 | /// for movie in &to_find { |
109 | /// match movie_reviews.get(movie) { | |
5e7ed085 FG |
110 | /// Some(review) => println!("{movie}: {review}"), |
111 | /// None => println!("{movie} is unreviewed.") | |
54a0048b SL |
112 | /// } |
113 | /// } | |
114 | /// | |
0731742a XL |
115 | /// // Look up the value for a key (will panic if the key is not found). |
116 | /// println!("Movie review: {}", movie_reviews["Office Space"]); | |
117 | /// | |
54a0048b SL |
118 | /// // iterate over everything. |
119 | /// for (movie, review) in &movie_reviews { | |
5e7ed085 | 120 | /// println!("{movie}: \"{review}\""); |
54a0048b SL |
121 | /// } |
122 | /// ``` | |
123 | /// | |
94222f64 XL |
124 | /// A `BTreeMap` with a known list of items can be initialized from an array: |
125 | /// | |
126 | /// ``` | |
127 | /// use std::collections::BTreeMap; | |
128 | /// | |
129 | /// let solar_distance = BTreeMap::from([ | |
130 | /// ("Mercury", 0.4), | |
131 | /// ("Venus", 0.7), | |
132 | /// ("Earth", 1.0), | |
133 | /// ("Mars", 1.5), | |
134 | /// ]); | |
135 | /// ``` | |
136 | /// | |
137 | /// `BTreeMap` implements an [`Entry API`], which allows for complex | |
1b1a35ee XL |
138 | /// methods of getting, setting, updating and removing keys and their values: |
139 | /// | |
140 | /// [`Entry API`]: BTreeMap::entry | |
54a0048b SL |
141 | /// |
142 | /// ``` | |
143 | /// use std::collections::BTreeMap; | |
144 | /// | |
145 | /// // type inference lets us omit an explicit type signature (which | |
146 | /// // would be `BTreeMap<&str, u8>` in this example). | |
147 | /// let mut player_stats = BTreeMap::new(); | |
148 | /// | |
149 | /// fn random_stat_buff() -> u8 { | |
150 | /// // could actually return some random value here - let's just return | |
151 | /// // some fixed value for now | |
152 | /// 42 | |
153 | /// } | |
154 | /// | |
155 | /// // insert a key only if it doesn't already exist | |
156 | /// player_stats.entry("health").or_insert(100); | |
157 | /// | |
158 | /// // insert a key using a function that provides a new value only if it | |
159 | /// // doesn't already exist | |
160 | /// player_stats.entry("defence").or_insert_with(random_stat_buff); | |
161 | /// | |
162 | /// // update a key, guarding against the key possibly not being set | |
163 | /// let stat = player_stats.entry("attack").or_insert(100); | |
164 | /// *stat += random_stat_buff(); | |
923072b8 FG |
165 | /// |
166 | /// // modify an entry before an insert with in-place mutation | |
167 | /// player_stats.entry("mana").and_modify(|mana| *mana += 200).or_insert(100); | |
54a0048b | 168 | /// ``` |
85aaf69f | 169 | #[stable(feature = "rust1", since = "1.0.0")] |
6a06907d | 170 | #[cfg_attr(not(test), rustc_diagnostic_item = "BTreeMap")] |
94222f64 | 171 | #[rustc_insignificant_dtor] |
923072b8 FG |
172 | pub struct BTreeMap< |
173 | K, | |
174 | V, | |
175 | #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + Clone = Global, | |
176 | > { | |
fc512014 | 177 | root: Option<Root<K, V>>, |
3157f602 | 178 | length: usize, |
923072b8 FG |
179 | /// `ManuallyDrop` to control drop order (needs to be dropped after all the nodes). |
180 | pub(super) alloc: ManuallyDrop<A>, | |
064997fb FG |
181 | // For dropck; the `Box` avoids making the `Unpin` impl more strict than before |
182 | _marker: PhantomData<crate::boxed::Box<(K, V)>>, | |
9cc50fc6 SL |
183 | } |
184 | ||
c30ab7b3 | 185 | #[stable(feature = "btree_drop", since = "1.7.0")] |
923072b8 | 186 | unsafe impl<#[may_dangle] K, #[may_dangle] V, A: Allocator + Clone> Drop for BTreeMap<K, V, A> { |
9cc50fc6 | 187 | fn drop(&mut self) { |
94222f64 | 188 | drop(unsafe { ptr::read(self) }.into_iter()) |
9cc50fc6 SL |
189 | } |
190 | } | |
191 | ||
064997fb FG |
192 | // FIXME: This implementation is "wrong", but changing it would be a breaking change. |
193 | // (The bounds of the automatic `UnwindSafe` implementation have been like this since Rust 1.50.) | |
194 | // Maybe we can fix it nonetheless with a crater run, or if the `UnwindSafe` | |
195 | // traits are deprecated, or disarmed (no longer causing hard errors) in the future. | |
196 | #[stable(feature = "btree_unwindsafe", since = "1.64.0")] | |
197 | impl<K, V, A: Allocator + Clone> core::panic::UnwindSafe for BTreeMap<K, V, A> | |
198 | where | |
199 | A: core::panic::UnwindSafe, | |
200 | K: core::panic::RefUnwindSafe, | |
201 | V: core::panic::RefUnwindSafe, | |
202 | { | |
203 | } | |
204 | ||
c30ab7b3 | 205 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 FG |
206 | impl<K: Clone, V: Clone, A: Allocator + Clone> Clone for BTreeMap<K, V, A> { |
207 | fn clone(&self) -> BTreeMap<K, V, A> { | |
208 | fn clone_subtree<'a, K: Clone, V: Clone, A: Allocator + Clone>( | |
fc512014 | 209 | node: NodeRef<marker::Immut<'a>, K, V, marker::LeafOrInternal>, |
923072b8 FG |
210 | alloc: A, |
211 | ) -> BTreeMap<K, V, A> | |
dfeec247 XL |
212 | where |
213 | K: 'a, | |
214 | V: 'a, | |
8faf50e0 | 215 | { |
9cc50fc6 SL |
216 | match node.force() { |
217 | Leaf(leaf) => { | |
923072b8 FG |
218 | let mut out_tree = BTreeMap { |
219 | root: Some(Root::new(alloc.clone())), | |
220 | length: 0, | |
221 | alloc: ManuallyDrop::new(alloc), | |
064997fb | 222 | _marker: PhantomData, |
923072b8 | 223 | }; |
9cc50fc6 SL |
224 | |
225 | { | |
3dfed10e | 226 | let root = out_tree.root.as_mut().unwrap(); // unwrap succeeds because we just wrapped |
fc512014 | 227 | let mut out_node = match root.borrow_mut().force() { |
9cc50fc6 | 228 | Leaf(leaf) => leaf, |
3157f602 | 229 | Internal(_) => unreachable!(), |
9cc50fc6 SL |
230 | }; |
231 | ||
232 | let mut in_edge = leaf.first_edge(); | |
233 | while let Ok(kv) = in_edge.right_kv() { | |
234 | let (k, v) = kv.into_kv(); | |
235 | in_edge = kv.right_edge(); | |
236 | ||
237 | out_node.push(k.clone(), v.clone()); | |
238 | out_tree.length += 1; | |
239 | } | |
240 | } | |
241 | ||
242 | out_tree | |
3157f602 | 243 | } |
9cc50fc6 | 244 | Internal(internal) => { |
923072b8 FG |
245 | let mut out_tree = |
246 | clone_subtree(internal.first_edge().descend(), alloc.clone()); | |
9cc50fc6 SL |
247 | |
248 | { | |
5e7ed085 | 249 | let out_root = out_tree.root.as_mut().unwrap(); |
923072b8 | 250 | let mut out_node = out_root.push_internal_level(alloc.clone()); |
9cc50fc6 SL |
251 | let mut in_edge = internal.first_edge(); |
252 | while let Ok(kv) = in_edge.right_kv() { | |
253 | let (k, v) = kv.into_kv(); | |
254 | in_edge = kv.right_edge(); | |
255 | ||
256 | let k = (*k).clone(); | |
257 | let v = (*v).clone(); | |
923072b8 | 258 | let subtree = clone_subtree(in_edge.descend(), alloc.clone()); |
9cc50fc6 SL |
259 | |
260 | // We can't destructure subtree directly | |
261 | // because BTreeMap implements Drop | |
262 | let (subroot, sublength) = unsafe { | |
ba9703b0 | 263 | let subtree = ManuallyDrop::new(subtree); |
9cc50fc6 SL |
264 | let root = ptr::read(&subtree.root); |
265 | let length = subtree.length; | |
9cc50fc6 SL |
266 | (root, length) |
267 | }; | |
268 | ||
923072b8 FG |
269 | out_node.push( |
270 | k, | |
271 | v, | |
272 | subroot.unwrap_or_else(|| Root::new(alloc.clone())), | |
273 | ); | |
9cc50fc6 SL |
274 | out_tree.length += 1 + sublength; |
275 | } | |
276 | } | |
277 | ||
278 | out_tree | |
279 | } | |
280 | } | |
281 | } | |
282 | ||
416331ca | 283 | if self.is_empty() { |
923072b8 | 284 | BTreeMap::new_in((*self.alloc).clone()) |
8faf50e0 | 285 | } else { |
923072b8 | 286 | clone_subtree(self.root.as_ref().unwrap().reborrow(), (*self.alloc).clone()) // unwrap succeeds because not empty |
8faf50e0 | 287 | } |
9cc50fc6 | 288 | } |
1a4d82fc JJ |
289 | } |
290 | ||
923072b8 | 291 | impl<K, Q: ?Sized, A: Allocator + Clone> super::Recover<Q> for BTreeMap<K, SetValZST, A> |
dfeec247 XL |
292 | where |
293 | K: Borrow<Q> + Ord, | |
294 | Q: Ord, | |
9cc50fc6 SL |
295 | { |
296 | type Key = K; | |
297 | ||
298 | fn get(&self, key: &Q) -> Option<&K> { | |
fc512014 | 299 | let root_node = self.root.as_ref()?.reborrow(); |
5869c6ff | 300 | match root_node.search_tree(key) { |
9cc50fc6 | 301 | Found(handle) => Some(handle.into_kv().0), |
3157f602 | 302 | GoDown(_) => None, |
9cc50fc6 SL |
303 | } |
304 | } | |
305 | ||
306 | fn take(&mut self, key: &Q) -> Option<K> { | |
1b1a35ee | 307 | let (map, dormant_map) = DormantMutRef::new(self); |
fc512014 | 308 | let root_node = map.root.as_mut()?.borrow_mut(); |
5869c6ff | 309 | match root_node.search_tree(key) { |
923072b8 FG |
310 | Found(handle) => Some( |
311 | OccupiedEntry { | |
312 | handle, | |
313 | dormant_map, | |
314 | alloc: (*map.alloc).clone(), | |
315 | _marker: PhantomData, | |
316 | } | |
317 | .remove_kv() | |
318 | .0, | |
319 | ), | |
3157f602 | 320 | GoDown(_) => None, |
9cc50fc6 SL |
321 | } |
322 | } | |
323 | ||
324 | fn replace(&mut self, key: K) -> Option<K> { | |
1b1a35ee | 325 | let (map, dormant_map) = DormantMutRef::new(self); |
923072b8 FG |
326 | let root_node = |
327 | map.root.get_or_insert_with(|| Root::new((*map.alloc).clone())).borrow_mut(); | |
5869c6ff | 328 | match root_node.search_tree::<K>(&key) { |
fc512014 | 329 | Found(mut kv) => Some(mem::replace(kv.key_mut(), key)), |
9cc50fc6 | 330 | GoDown(handle) => { |
923072b8 FG |
331 | VacantEntry { |
332 | key, | |
333 | handle: Some(handle), | |
334 | dormant_map, | |
335 | alloc: (*map.alloc).clone(), | |
336 | _marker: PhantomData, | |
337 | } | |
338 | .insert(SetValZST::default()); | |
9cc50fc6 SL |
339 | None |
340 | } | |
341 | } | |
342 | } | |
1a4d82fc JJ |
343 | } |
344 | ||
cc61c64b XL |
345 | /// An iterator over the entries of a `BTreeMap`. |
346 | /// | |
347 | /// This `struct` is created by the [`iter`] method on [`BTreeMap`]. See its | |
348 | /// documentation for more. | |
349 | /// | |
3dfed10e | 350 | /// [`iter`]: BTreeMap::iter |
3c0e092e | 351 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
85aaf69f | 352 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 353 | pub struct Iter<'a, K: 'a, V: 'a> { |
94222f64 | 354 | range: LazyLeafRange<marker::Immut<'a>, K, V>, |
3157f602 | 355 | length: usize, |
1a4d82fc JJ |
356 | } |
357 | ||
8bb4bdeb | 358 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
359 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Iter<'_, K, V> { |
360 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
8bb4bdeb XL |
361 | f.debug_list().entries(self.clone()).finish() |
362 | } | |
363 | } | |
364 | ||
353b0b11 FG |
365 | #[stable(feature = "default_iters", since = "1.70.0")] |
366 | impl<'a, K: 'a, V: 'a> Default for Iter<'a, K, V> { | |
367 | /// Creates an empty `btree_map::Iter`. | |
368 | /// | |
369 | /// ``` | |
370 | /// # use std::collections::btree_map; | |
371 | /// let iter: btree_map::Iter<'_, u8, u8> = Default::default(); | |
372 | /// assert_eq!(iter.len(), 0); | |
373 | /// ``` | |
374 | fn default() -> Self { | |
375 | Iter { range: Default::default(), length: 0 } | |
376 | } | |
377 | } | |
378 | ||
cc61c64b XL |
379 | /// A mutable iterator over the entries of a `BTreeMap`. |
380 | /// | |
381 | /// This `struct` is created by the [`iter_mut`] method on [`BTreeMap`]. See its | |
382 | /// documentation for more. | |
383 | /// | |
3dfed10e | 384 | /// [`iter_mut`]: BTreeMap::iter_mut |
85aaf69f | 385 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 386 | pub struct IterMut<'a, K: 'a, V: 'a> { |
94222f64 | 387 | range: LazyLeafRange<marker::ValMut<'a>, K, V>, |
3157f602 | 388 | length: usize, |
94222f64 XL |
389 | |
390 | // Be invariant in `K` and `V` | |
391 | _marker: PhantomData<&'a mut (K, V)>, | |
392 | } | |
393 | ||
3c0e092e | 394 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
94222f64 XL |
395 | #[stable(feature = "collection_debug", since = "1.17.0")] |
396 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IterMut<'_, K, V> { | |
397 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
398 | let range = Iter { range: self.range.reborrow(), length: self.length }; | |
399 | f.debug_list().entries(range).finish() | |
400 | } | |
1a4d82fc JJ |
401 | } |
402 | ||
353b0b11 FG |
403 | #[stable(feature = "default_iters", since = "1.70.0")] |
404 | impl<'a, K: 'a, V: 'a> Default for IterMut<'a, K, V> { | |
405 | /// Creates an empty `btree_map::IterMut`. | |
406 | /// | |
407 | /// ``` | |
408 | /// # use std::collections::btree_map; | |
409 | /// let iter: btree_map::IterMut<'_, u8, u8> = Default::default(); | |
410 | /// assert_eq!(iter.len(), 0); | |
411 | /// ``` | |
412 | fn default() -> Self { | |
413 | IterMut { range: Default::default(), length: 0, _marker: PhantomData {} } | |
414 | } | |
415 | } | |
416 | ||
cc61c64b XL |
417 | /// An owning iterator over the entries of a `BTreeMap`. |
418 | /// | |
dfeec247 | 419 | /// This `struct` is created by the [`into_iter`] method on [`BTreeMap`] |
c295e0f8 | 420 | /// (provided by the [`IntoIterator`] trait). See its documentation for more. |
cc61c64b | 421 | /// |
3dfed10e | 422 | /// [`into_iter`]: IntoIterator::into_iter |
85aaf69f | 423 | #[stable(feature = "rust1", since = "1.0.0")] |
94222f64 | 424 | #[rustc_insignificant_dtor] |
923072b8 FG |
425 | pub struct IntoIter< |
426 | K, | |
427 | V, | |
428 | #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + Clone = Global, | |
429 | > { | |
94222f64 | 430 | range: LazyLeafRange<marker::Dying, K, V>, |
3157f602 | 431 | length: usize, |
923072b8 FG |
432 | /// The BTreeMap will outlive this IntoIter so we don't care about drop order for `alloc`. |
433 | alloc: A, | |
1a4d82fc JJ |
434 | } |
435 | ||
923072b8 | 436 | impl<K, V, A: Allocator + Clone> IntoIter<K, V, A> { |
1b1a35ee XL |
437 | /// Returns an iterator of references over the remaining items. |
438 | #[inline] | |
439 | pub(super) fn iter(&self) -> Iter<'_, K, V> { | |
94222f64 | 440 | Iter { range: self.range.reborrow(), length: self.length } |
1b1a35ee XL |
441 | } |
442 | } | |
443 | ||
444 | #[stable(feature = "collection_debug", since = "1.17.0")] | |
923072b8 | 445 | impl<K: Debug, V: Debug, A: Allocator + Clone> Debug for IntoIter<K, V, A> { |
1b1a35ee XL |
446 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
447 | f.debug_list().entries(self.iter()).finish() | |
8bb4bdeb XL |
448 | } |
449 | } | |
450 | ||
353b0b11 FG |
451 | #[stable(feature = "default_iters", since = "1.70.0")] |
452 | impl<K, V, A> Default for IntoIter<K, V, A> | |
453 | where | |
454 | A: Allocator + Default + Clone, | |
455 | { | |
456 | /// Creates an empty `btree_map::IntoIter`. | |
457 | /// | |
458 | /// ``` | |
459 | /// # use std::collections::btree_map; | |
460 | /// let iter: btree_map::IntoIter<u8, u8> = Default::default(); | |
461 | /// assert_eq!(iter.len(), 0); | |
462 | /// ``` | |
463 | fn default() -> Self { | |
464 | IntoIter { range: Default::default(), length: 0, alloc: Default::default() } | |
465 | } | |
466 | } | |
467 | ||
cc61c64b XL |
468 | /// An iterator over the keys of a `BTreeMap`. |
469 | /// | |
470 | /// This `struct` is created by the [`keys`] method on [`BTreeMap`]. See its | |
471 | /// documentation for more. | |
472 | /// | |
3dfed10e | 473 | /// [`keys`]: BTreeMap::keys |
3c0e092e | 474 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
85aaf69f | 475 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 476 | pub struct Keys<'a, K, V> { |
9cc50fc6 | 477 | inner: Iter<'a, K, V>, |
1a4d82fc JJ |
478 | } |
479 | ||
8bb4bdeb | 480 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
481 | impl<K: fmt::Debug, V> fmt::Debug for Keys<'_, K, V> { |
482 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
041b39d2 | 483 | f.debug_list().entries(self.clone()).finish() |
8bb4bdeb XL |
484 | } |
485 | } | |
486 | ||
cc61c64b XL |
487 | /// An iterator over the values of a `BTreeMap`. |
488 | /// | |
489 | /// This `struct` is created by the [`values`] method on [`BTreeMap`]. See its | |
490 | /// documentation for more. | |
491 | /// | |
3dfed10e | 492 | /// [`values`]: BTreeMap::values |
3c0e092e | 493 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
85aaf69f | 494 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 495 | pub struct Values<'a, K, V> { |
9cc50fc6 | 496 | inner: Iter<'a, K, V>, |
85aaf69f SL |
497 | } |
498 | ||
8bb4bdeb | 499 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
500 | impl<K, V: fmt::Debug> fmt::Debug for Values<'_, K, V> { |
501 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
041b39d2 | 502 | f.debug_list().entries(self.clone()).finish() |
8bb4bdeb XL |
503 | } |
504 | } | |
505 | ||
cc61c64b XL |
506 | /// A mutable iterator over the values of a `BTreeMap`. |
507 | /// | |
508 | /// This `struct` is created by the [`values_mut`] method on [`BTreeMap`]. See its | |
509 | /// documentation for more. | |
510 | /// | |
3dfed10e | 511 | /// [`values_mut`]: BTreeMap::values_mut |
3c0e092e | 512 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
a7813a04 | 513 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
923072b8 | 514 | pub struct ValuesMut<'a, K, V> { |
54a0048b SL |
515 | inner: IterMut<'a, K, V>, |
516 | } | |
517 | ||
1b1a35ee XL |
518 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
519 | impl<K, V: fmt::Debug> fmt::Debug for ValuesMut<'_, K, V> { | |
520 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
521 | f.debug_list().entries(self.inner.iter().map(|(_, val)| val)).finish() | |
522 | } | |
523 | } | |
524 | ||
3dfed10e XL |
525 | /// An owning iterator over the keys of a `BTreeMap`. |
526 | /// | |
527 | /// This `struct` is created by the [`into_keys`] method on [`BTreeMap`]. | |
528 | /// See its documentation for more. | |
529 | /// | |
530 | /// [`into_keys`]: BTreeMap::into_keys | |
3c0e092e | 531 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
17df50a5 | 532 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 FG |
533 | pub struct IntoKeys<K, V, A: Allocator + Clone = Global> { |
534 | inner: IntoIter<K, V, A>, | |
3dfed10e XL |
535 | } |
536 | ||
17df50a5 | 537 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 538 | impl<K: fmt::Debug, V, A: Allocator + Clone> fmt::Debug for IntoKeys<K, V, A> { |
1b1a35ee XL |
539 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
540 | f.debug_list().entries(self.inner.iter().map(|(key, _)| key)).finish() | |
541 | } | |
542 | } | |
543 | ||
3dfed10e XL |
544 | /// An owning iterator over the values of a `BTreeMap`. |
545 | /// | |
546 | /// This `struct` is created by the [`into_values`] method on [`BTreeMap`]. | |
547 | /// See its documentation for more. | |
548 | /// | |
549 | /// [`into_values`]: BTreeMap::into_values | |
3c0e092e | 550 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
17df50a5 | 551 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 FG |
552 | pub struct IntoValues< |
553 | K, | |
554 | V, | |
555 | #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + Clone = Global, | |
556 | > { | |
557 | inner: IntoIter<K, V, A>, | |
3dfed10e XL |
558 | } |
559 | ||
17df50a5 | 560 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 561 | impl<K, V: fmt::Debug, A: Allocator + Clone> fmt::Debug for IntoValues<K, V, A> { |
1b1a35ee XL |
562 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
563 | f.debug_list().entries(self.inner.iter().map(|(_, val)| val)).finish() | |
564 | } | |
565 | } | |
566 | ||
cc61c64b XL |
567 | /// An iterator over a sub-range of entries in a `BTreeMap`. |
568 | /// | |
569 | /// This `struct` is created by the [`range`] method on [`BTreeMap`]. See its | |
570 | /// documentation for more. | |
571 | /// | |
3dfed10e | 572 | /// [`range`]: BTreeMap::range |
3c0e092e | 573 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
8bb4bdeb | 574 | #[stable(feature = "btree_range", since = "1.17.0")] |
85aaf69f | 575 | pub struct Range<'a, K: 'a, V: 'a> { |
6a06907d | 576 | inner: LeafRange<marker::Immut<'a>, K, V>, |
85aaf69f SL |
577 | } |
578 | ||
8bb4bdeb | 579 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
580 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Range<'_, K, V> { |
581 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
8bb4bdeb XL |
582 | f.debug_list().entries(self.clone()).finish() |
583 | } | |
584 | } | |
585 | ||
cc61c64b XL |
586 | /// A mutable iterator over a sub-range of entries in a `BTreeMap`. |
587 | /// | |
588 | /// This `struct` is created by the [`range_mut`] method on [`BTreeMap`]. See its | |
589 | /// documentation for more. | |
590 | /// | |
3dfed10e | 591 | /// [`range_mut`]: BTreeMap::range_mut |
3c0e092e | 592 | #[must_use = "iterators are lazy and do nothing unless consumed"] |
8bb4bdeb | 593 | #[stable(feature = "btree_range", since = "1.17.0")] |
85aaf69f | 594 | pub struct RangeMut<'a, K: 'a, V: 'a> { |
6a06907d | 595 | inner: LeafRange<marker::ValMut<'a>, K, V>, |
9cc50fc6 SL |
596 | |
597 | // Be invariant in `K` and `V` | |
598 | _marker: PhantomData<&'a mut (K, V)>, | |
1a4d82fc JJ |
599 | } |
600 | ||
8bb4bdeb | 601 | #[stable(feature = "collection_debug", since = "1.17.0")] |
9fa01778 XL |
602 | impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for RangeMut<'_, K, V> { |
603 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
6a06907d | 604 | let range = Range { inner: self.inner.reborrow() }; |
8bb4bdeb XL |
605 | f.debug_list().entries(range).finish() |
606 | } | |
607 | } | |
608 | ||
5869c6ff | 609 | impl<K, V> BTreeMap<K, V> { |
fc512014 | 610 | /// Makes a new, empty `BTreeMap`. |
f035d41b XL |
611 | /// |
612 | /// Does not allocate anything on its own. | |
54a0048b SL |
613 | /// |
614 | /// # Examples | |
615 | /// | |
54a0048b SL |
616 | /// ``` |
617 | /// use std::collections::BTreeMap; | |
618 | /// | |
619 | /// let mut map = BTreeMap::new(); | |
620 | /// | |
621 | /// // entries can now be inserted into the empty map | |
622 | /// map.insert(1, "a"); | |
623 | /// ``` | |
85aaf69f | 624 | #[stable(feature = "rust1", since = "1.0.0")] |
2b03887a | 625 | #[rustc_const_stable(feature = "const_btree_new", since = "1.66.0")] |
c295e0f8 | 626 | #[must_use] |
94222f64 | 627 | pub const fn new() -> BTreeMap<K, V> { |
064997fb | 628 | BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(Global), _marker: PhantomData } |
1a4d82fc | 629 | } |
923072b8 | 630 | } |
1a4d82fc | 631 | |
923072b8 | 632 | impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> { |
dfeec247 | 633 | /// Clears the map, removing all elements. |
1a4d82fc JJ |
634 | /// |
635 | /// # Examples | |
636 | /// | |
637 | /// ``` | |
638 | /// use std::collections::BTreeMap; | |
639 | /// | |
640 | /// let mut a = BTreeMap::new(); | |
85aaf69f | 641 | /// a.insert(1, "a"); |
1a4d82fc JJ |
642 | /// a.clear(); |
643 | /// assert!(a.is_empty()); | |
644 | /// ``` | |
85aaf69f | 645 | #[stable(feature = "rust1", since = "1.0.0")] |
6a06907d | 646 | pub fn clear(&mut self) { |
923072b8 | 647 | // avoid moving the allocator |
353b0b11 | 648 | drop(BTreeMap { |
923072b8 FG |
649 | root: mem::replace(&mut self.root, None), |
650 | length: mem::replace(&mut self.length, 0), | |
651 | alloc: self.alloc.clone(), | |
064997fb | 652 | _marker: PhantomData, |
923072b8 FG |
653 | }); |
654 | } | |
655 | ||
656 | /// Makes a new empty BTreeMap with a reasonable choice for B. | |
657 | /// | |
658 | /// # Examples | |
659 | /// | |
923072b8 FG |
660 | /// ``` |
661 | /// # #![feature(allocator_api)] | |
662 | /// # #![feature(btreemap_alloc)] | |
663 | /// use std::collections::BTreeMap; | |
664 | /// use std::alloc::Global; | |
665 | /// | |
666 | /// let mut map = BTreeMap::new_in(Global); | |
667 | /// | |
668 | /// // entries can now be inserted into the empty map | |
669 | /// map.insert(1, "a"); | |
670 | /// ``` | |
671 | #[unstable(feature = "btreemap_alloc", issue = "32838")] | |
ed00b5ec | 672 | pub const fn new_in(alloc: A) -> BTreeMap<K, V, A> { |
064997fb | 673 | BTreeMap { root: None, length: 0, alloc: ManuallyDrop::new(alloc), _marker: PhantomData } |
1a4d82fc | 674 | } |
923072b8 | 675 | } |
1a4d82fc | 676 | |
923072b8 | 677 | impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> { |
1a4d82fc JJ |
678 | /// Returns a reference to the value corresponding to the key. |
679 | /// | |
680 | /// The key may be any borrowed form of the map's key type, but the ordering | |
681 | /// on the borrowed form *must* match the ordering on the key type. | |
682 | /// | |
683 | /// # Examples | |
684 | /// | |
685 | /// ``` | |
686 | /// use std::collections::BTreeMap; | |
687 | /// | |
688 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 689 | /// map.insert(1, "a"); |
1a4d82fc JJ |
690 | /// assert_eq!(map.get(&1), Some(&"a")); |
691 | /// assert_eq!(map.get(&2), None); | |
692 | /// ``` | |
85aaf69f | 693 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 694 | pub fn get<Q: ?Sized>(&self, key: &Q) -> Option<&V> |
dfeec247 | 695 | where |
5869c6ff | 696 | K: Borrow<Q> + Ord, |
dfeec247 | 697 | Q: Ord, |
3157f602 | 698 | { |
fc512014 | 699 | let root_node = self.root.as_ref()?.reborrow(); |
5869c6ff | 700 | match root_node.search_tree(key) { |
9cc50fc6 | 701 | Found(handle) => Some(handle.into_kv().1), |
3157f602 | 702 | GoDown(_) => None, |
1a4d82fc JJ |
703 | } |
704 | } | |
705 | ||
0531ce1d XL |
706 | /// Returns the key-value pair corresponding to the supplied key. |
707 | /// | |
708 | /// The supplied key may be any borrowed form of the map's key type, but the ordering | |
709 | /// on the borrowed form *must* match the ordering on the key type. | |
710 | /// | |
711 | /// # Examples | |
712 | /// | |
713 | /// ``` | |
0531ce1d XL |
714 | /// use std::collections::BTreeMap; |
715 | /// | |
716 | /// let mut map = BTreeMap::new(); | |
717 | /// map.insert(1, "a"); | |
718 | /// assert_eq!(map.get_key_value(&1), Some((&1, &"a"))); | |
719 | /// assert_eq!(map.get_key_value(&2), None); | |
720 | /// ``` | |
e74abb32 | 721 | #[stable(feature = "map_get_key_value", since = "1.40.0")] |
0531ce1d | 722 | pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)> |
dfeec247 | 723 | where |
5869c6ff | 724 | K: Borrow<Q> + Ord, |
dfeec247 | 725 | Q: Ord, |
0531ce1d | 726 | { |
fc512014 | 727 | let root_node = self.root.as_ref()?.reborrow(); |
5869c6ff | 728 | match root_node.search_tree(k) { |
0531ce1d XL |
729 | Found(handle) => Some(handle.into_kv()), |
730 | GoDown(_) => None, | |
731 | } | |
732 | } | |
733 | ||
60c5eb7d XL |
734 | /// Returns the first key-value pair in the map. |
735 | /// The key in this pair is the minimum key in the map. | |
736 | /// | |
737 | /// # Examples | |
738 | /// | |
60c5eb7d | 739 | /// ``` |
60c5eb7d XL |
740 | /// use std::collections::BTreeMap; |
741 | /// | |
742 | /// let mut map = BTreeMap::new(); | |
743 | /// assert_eq!(map.first_key_value(), None); | |
744 | /// map.insert(1, "b"); | |
745 | /// map.insert(2, "a"); | |
746 | /// assert_eq!(map.first_key_value(), Some((&1, &"b"))); | |
747 | /// ``` | |
2b03887a | 748 | #[stable(feature = "map_first_last", since = "1.66.0")] |
5869c6ff XL |
749 | pub fn first_key_value(&self) -> Option<(&K, &V)> |
750 | where | |
751 | K: Ord, | |
752 | { | |
fc512014 | 753 | let root_node = self.root.as_ref()?.reborrow(); |
3dfed10e | 754 | root_node.first_leaf_edge().right_kv().ok().map(Handle::into_kv) |
60c5eb7d XL |
755 | } |
756 | ||
757 | /// Returns the first entry in the map for in-place manipulation. | |
758 | /// The key of this entry is the minimum key in the map. | |
759 | /// | |
760 | /// # Examples | |
761 | /// | |
ba9703b0 | 762 | /// ``` |
ba9703b0 XL |
763 | /// use std::collections::BTreeMap; |
764 | /// | |
765 | /// let mut map = BTreeMap::new(); | |
766 | /// map.insert(1, "a"); | |
767 | /// map.insert(2, "b"); | |
768 | /// if let Some(mut entry) = map.first_entry() { | |
769 | /// if *entry.key() > 0 { | |
770 | /// entry.insert("first"); | |
771 | /// } | |
772 | /// } | |
773 | /// assert_eq!(*map.get(&1).unwrap(), "first"); | |
774 | /// assert_eq!(*map.get(&2).unwrap(), "b"); | |
775 | /// ``` | |
2b03887a | 776 | #[stable(feature = "map_first_last", since = "1.66.0")] |
923072b8 | 777 | pub fn first_entry(&mut self) -> Option<OccupiedEntry<'_, K, V, A>> |
5869c6ff XL |
778 | where |
779 | K: Ord, | |
780 | { | |
1b1a35ee | 781 | let (map, dormant_map) = DormantMutRef::new(self); |
fc512014 | 782 | let root_node = map.root.as_mut()?.borrow_mut(); |
3dfed10e | 783 | let kv = root_node.first_leaf_edge().right_kv().ok()?; |
923072b8 FG |
784 | Some(OccupiedEntry { |
785 | handle: kv.forget_node_type(), | |
786 | dormant_map, | |
787 | alloc: (*map.alloc).clone(), | |
788 | _marker: PhantomData, | |
789 | }) | |
ba9703b0 XL |
790 | } |
791 | ||
792 | /// Removes and returns the first element in the map. | |
793 | /// The key of this element is the minimum key that was in the map. | |
794 | /// | |
795 | /// # Examples | |
796 | /// | |
797 | /// Draining elements in ascending order, while keeping a usable map each iteration. | |
60c5eb7d XL |
798 | /// |
799 | /// ``` | |
60c5eb7d XL |
800 | /// use std::collections::BTreeMap; |
801 | /// | |
802 | /// let mut map = BTreeMap::new(); | |
803 | /// map.insert(1, "a"); | |
804 | /// map.insert(2, "b"); | |
ba9703b0 XL |
805 | /// while let Some((key, _val)) = map.pop_first() { |
806 | /// assert!(map.iter().all(|(k, _v)| *k > key)); | |
60c5eb7d | 807 | /// } |
ba9703b0 | 808 | /// assert!(map.is_empty()); |
60c5eb7d | 809 | /// ``` |
2b03887a | 810 | #[stable(feature = "map_first_last", since = "1.66.0")] |
5869c6ff XL |
811 | pub fn pop_first(&mut self) -> Option<(K, V)> |
812 | where | |
813 | K: Ord, | |
814 | { | |
ba9703b0 | 815 | self.first_entry().map(|entry| entry.remove_entry()) |
60c5eb7d XL |
816 | } |
817 | ||
818 | /// Returns the last key-value pair in the map. | |
819 | /// The key in this pair is the maximum key in the map. | |
820 | /// | |
821 | /// # Examples | |
822 | /// | |
60c5eb7d | 823 | /// ``` |
60c5eb7d XL |
824 | /// use std::collections::BTreeMap; |
825 | /// | |
826 | /// let mut map = BTreeMap::new(); | |
827 | /// map.insert(1, "b"); | |
828 | /// map.insert(2, "a"); | |
829 | /// assert_eq!(map.last_key_value(), Some((&2, &"a"))); | |
830 | /// ``` | |
2b03887a | 831 | #[stable(feature = "map_first_last", since = "1.66.0")] |
5869c6ff XL |
832 | pub fn last_key_value(&self) -> Option<(&K, &V)> |
833 | where | |
834 | K: Ord, | |
835 | { | |
fc512014 | 836 | let root_node = self.root.as_ref()?.reborrow(); |
3dfed10e | 837 | root_node.last_leaf_edge().left_kv().ok().map(Handle::into_kv) |
60c5eb7d XL |
838 | } |
839 | ||
840 | /// Returns the last entry in the map for in-place manipulation. | |
841 | /// The key of this entry is the maximum key in the map. | |
842 | /// | |
843 | /// # Examples | |
844 | /// | |
ba9703b0 | 845 | /// ``` |
ba9703b0 XL |
846 | /// use std::collections::BTreeMap; |
847 | /// | |
848 | /// let mut map = BTreeMap::new(); | |
849 | /// map.insert(1, "a"); | |
850 | /// map.insert(2, "b"); | |
851 | /// if let Some(mut entry) = map.last_entry() { | |
852 | /// if *entry.key() > 0 { | |
853 | /// entry.insert("last"); | |
854 | /// } | |
855 | /// } | |
856 | /// assert_eq!(*map.get(&1).unwrap(), "a"); | |
857 | /// assert_eq!(*map.get(&2).unwrap(), "last"); | |
858 | /// ``` | |
2b03887a | 859 | #[stable(feature = "map_first_last", since = "1.66.0")] |
923072b8 | 860 | pub fn last_entry(&mut self) -> Option<OccupiedEntry<'_, K, V, A>> |
5869c6ff XL |
861 | where |
862 | K: Ord, | |
863 | { | |
1b1a35ee | 864 | let (map, dormant_map) = DormantMutRef::new(self); |
fc512014 | 865 | let root_node = map.root.as_mut()?.borrow_mut(); |
3dfed10e | 866 | let kv = root_node.last_leaf_edge().left_kv().ok()?; |
923072b8 FG |
867 | Some(OccupiedEntry { |
868 | handle: kv.forget_node_type(), | |
869 | dormant_map, | |
870 | alloc: (*map.alloc).clone(), | |
871 | _marker: PhantomData, | |
872 | }) | |
ba9703b0 XL |
873 | } |
874 | ||
875 | /// Removes and returns the last element in the map. | |
876 | /// The key of this element is the maximum key that was in the map. | |
877 | /// | |
878 | /// # Examples | |
879 | /// | |
880 | /// Draining elements in descending order, while keeping a usable map each iteration. | |
60c5eb7d XL |
881 | /// |
882 | /// ``` | |
60c5eb7d XL |
883 | /// use std::collections::BTreeMap; |
884 | /// | |
885 | /// let mut map = BTreeMap::new(); | |
886 | /// map.insert(1, "a"); | |
887 | /// map.insert(2, "b"); | |
ba9703b0 XL |
888 | /// while let Some((key, _val)) = map.pop_last() { |
889 | /// assert!(map.iter().all(|(k, _v)| *k < key)); | |
60c5eb7d | 890 | /// } |
ba9703b0 | 891 | /// assert!(map.is_empty()); |
60c5eb7d | 892 | /// ``` |
2b03887a | 893 | #[stable(feature = "map_first_last", since = "1.66.0")] |
5869c6ff XL |
894 | pub fn pop_last(&mut self) -> Option<(K, V)> |
895 | where | |
896 | K: Ord, | |
897 | { | |
ba9703b0 | 898 | self.last_entry().map(|entry| entry.remove_entry()) |
60c5eb7d XL |
899 | } |
900 | ||
cc61c64b | 901 | /// Returns `true` if the map contains a value for the specified key. |
1a4d82fc JJ |
902 | /// |
903 | /// The key may be any borrowed form of the map's key type, but the ordering | |
904 | /// on the borrowed form *must* match the ordering on the key type. | |
905 | /// | |
906 | /// # Examples | |
907 | /// | |
908 | /// ``` | |
909 | /// use std::collections::BTreeMap; | |
910 | /// | |
911 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 912 | /// map.insert(1, "a"); |
1a4d82fc JJ |
913 | /// assert_eq!(map.contains_key(&1), true); |
914 | /// assert_eq!(map.contains_key(&2), false); | |
915 | /// ``` | |
85aaf69f | 916 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 917 | pub fn contains_key<Q: ?Sized>(&self, key: &Q) -> bool |
dfeec247 | 918 | where |
5869c6ff | 919 | K: Borrow<Q> + Ord, |
dfeec247 | 920 | Q: Ord, |
3157f602 | 921 | { |
1a4d82fc JJ |
922 | self.get(key).is_some() |
923 | } | |
924 | ||
925 | /// Returns a mutable reference to the value corresponding to the key. | |
926 | /// | |
927 | /// The key may be any borrowed form of the map's key type, but the ordering | |
928 | /// on the borrowed form *must* match the ordering on the key type. | |
929 | /// | |
930 | /// # Examples | |
931 | /// | |
932 | /// ``` | |
933 | /// use std::collections::BTreeMap; | |
934 | /// | |
935 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 936 | /// map.insert(1, "a"); |
9346a6ac AL |
937 | /// if let Some(x) = map.get_mut(&1) { |
938 | /// *x = "b"; | |
1a4d82fc | 939 | /// } |
c34b1796 | 940 | /// assert_eq!(map[&1], "b"); |
1a4d82fc JJ |
941 | /// ``` |
942 | // See `get` for implementation notes, this is basically a copy-paste with mut's added | |
85aaf69f | 943 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 944 | pub fn get_mut<Q: ?Sized>(&mut self, key: &Q) -> Option<&mut V> |
dfeec247 | 945 | where |
5869c6ff | 946 | K: Borrow<Q> + Ord, |
dfeec247 | 947 | Q: Ord, |
3157f602 | 948 | { |
fc512014 | 949 | let root_node = self.root.as_mut()?.borrow_mut(); |
5869c6ff | 950 | match root_node.search_tree(key) { |
3dfed10e | 951 | Found(handle) => Some(handle.into_val_mut()), |
3157f602 | 952 | GoDown(_) => None, |
1a4d82fc JJ |
953 | } |
954 | } | |
955 | ||
b039eaaf SL |
956 | /// Inserts a key-value pair into the map. |
957 | /// | |
958 | /// If the map did not have this key present, `None` is returned. | |
959 | /// | |
7453a54e SL |
960 | /// If the map did have this key present, the value is updated, and the old |
961 | /// value is returned. The key is not updated, though; this matters for | |
962 | /// types that can be `==` without being identical. See the [module-level | |
963 | /// documentation] for more. | |
b039eaaf SL |
964 | /// |
965 | /// [module-level documentation]: index.html#insert-and-complex-keys | |
1a4d82fc JJ |
966 | /// |
967 | /// # Examples | |
968 | /// | |
969 | /// ``` | |
970 | /// use std::collections::BTreeMap; | |
971 | /// | |
972 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 973 | /// assert_eq!(map.insert(37, "a"), None); |
1a4d82fc JJ |
974 | /// assert_eq!(map.is_empty(), false); |
975 | /// | |
976 | /// map.insert(37, "b"); | |
977 | /// assert_eq!(map.insert(37, "c"), Some("b")); | |
c34b1796 | 978 | /// assert_eq!(map[&37], "c"); |
1a4d82fc | 979 | /// ``` |
85aaf69f | 980 | #[stable(feature = "rust1", since = "1.0.0")] |
5869c6ff XL |
981 | pub fn insert(&mut self, key: K, value: V) -> Option<V> |
982 | where | |
983 | K: Ord, | |
984 | { | |
9cc50fc6 SL |
985 | match self.entry(key) { |
986 | Occupied(mut entry) => Some(entry.insert(value)), | |
987 | Vacant(entry) => { | |
988 | entry.insert(value); | |
989 | None | |
1a4d82fc JJ |
990 | } |
991 | } | |
992 | } | |
993 | ||
6a06907d XL |
994 | /// Tries to insert a key-value pair into the map, and returns |
995 | /// a mutable reference to the value in the entry. | |
996 | /// | |
997 | /// If the map already had this key present, nothing is updated, and | |
998 | /// an error containing the occupied entry and the value is returned. | |
999 | /// | |
1000 | /// # Examples | |
1001 | /// | |
6a06907d XL |
1002 | /// ``` |
1003 | /// #![feature(map_try_insert)] | |
1004 | /// | |
1005 | /// use std::collections::BTreeMap; | |
1006 | /// | |
1007 | /// let mut map = BTreeMap::new(); | |
1008 | /// assert_eq!(map.try_insert(37, "a").unwrap(), &"a"); | |
1009 | /// | |
1010 | /// let err = map.try_insert(37, "b").unwrap_err(); | |
1011 | /// assert_eq!(err.entry.key(), &37); | |
1012 | /// assert_eq!(err.entry.get(), &"a"); | |
1013 | /// assert_eq!(err.value, "b"); | |
1014 | /// ``` | |
1015 | #[unstable(feature = "map_try_insert", issue = "82766")] | |
923072b8 | 1016 | pub fn try_insert(&mut self, key: K, value: V) -> Result<&mut V, OccupiedError<'_, K, V, A>> |
6a06907d XL |
1017 | where |
1018 | K: Ord, | |
1019 | { | |
1020 | match self.entry(key) { | |
1021 | Occupied(entry) => Err(OccupiedError { entry, value }), | |
1022 | Vacant(entry) => Ok(entry.insert(value)), | |
1023 | } | |
1024 | } | |
1025 | ||
1a4d82fc JJ |
1026 | /// Removes a key from the map, returning the value at the key if the key |
1027 | /// was previously in the map. | |
1028 | /// | |
1029 | /// The key may be any borrowed form of the map's key type, but the ordering | |
1030 | /// on the borrowed form *must* match the ordering on the key type. | |
1031 | /// | |
1032 | /// # Examples | |
1033 | /// | |
1034 | /// ``` | |
1035 | /// use std::collections::BTreeMap; | |
1036 | /// | |
1037 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 1038 | /// map.insert(1, "a"); |
1a4d82fc JJ |
1039 | /// assert_eq!(map.remove(&1), Some("a")); |
1040 | /// assert_eq!(map.remove(&1), None); | |
1041 | /// ``` | |
85aaf69f | 1042 | #[stable(feature = "rust1", since = "1.0.0")] |
3157f602 | 1043 | pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V> |
74b04a01 | 1044 | where |
5869c6ff | 1045 | K: Borrow<Q> + Ord, |
74b04a01 XL |
1046 | Q: Ord, |
1047 | { | |
1048 | self.remove_entry(key).map(|(_, v)| v) | |
1049 | } | |
1050 | ||
1051 | /// Removes a key from the map, returning the stored key and value if the key | |
1052 | /// was previously in the map. | |
1053 | /// | |
1054 | /// The key may be any borrowed form of the map's key type, but the ordering | |
1055 | /// on the borrowed form *must* match the ordering on the key type. | |
1056 | /// | |
1057 | /// # Examples | |
1058 | /// | |
74b04a01 | 1059 | /// ``` |
74b04a01 XL |
1060 | /// use std::collections::BTreeMap; |
1061 | /// | |
1062 | /// let mut map = BTreeMap::new(); | |
1063 | /// map.insert(1, "a"); | |
1064 | /// assert_eq!(map.remove_entry(&1), Some((1, "a"))); | |
1065 | /// assert_eq!(map.remove_entry(&1), None); | |
1066 | /// ``` | |
f9f354fc | 1067 | #[stable(feature = "btreemap_remove_entry", since = "1.45.0")] |
74b04a01 | 1068 | pub fn remove_entry<Q: ?Sized>(&mut self, key: &Q) -> Option<(K, V)> |
dfeec247 | 1069 | where |
5869c6ff | 1070 | K: Borrow<Q> + Ord, |
dfeec247 | 1071 | Q: Ord, |
3157f602 | 1072 | { |
1b1a35ee | 1073 | let (map, dormant_map) = DormantMutRef::new(self); |
fc512014 | 1074 | let root_node = map.root.as_mut()?.borrow_mut(); |
5869c6ff | 1075 | match root_node.search_tree(key) { |
923072b8 FG |
1076 | Found(handle) => Some( |
1077 | OccupiedEntry { | |
1078 | handle, | |
1079 | dormant_map, | |
1080 | alloc: (*map.alloc).clone(), | |
1081 | _marker: PhantomData, | |
1082 | } | |
1083 | .remove_entry(), | |
1084 | ), | |
3157f602 | 1085 | GoDown(_) => None, |
1a4d82fc JJ |
1086 | } |
1087 | } | |
85aaf69f | 1088 | |
fc512014 XL |
1089 | /// Retains only the elements specified by the predicate. |
1090 | /// | |
5e7ed085 | 1091 | /// In other words, remove all pairs `(k, v)` for which `f(&k, &mut v)` returns `false`. |
136023e0 | 1092 | /// The elements are visited in ascending key order. |
fc512014 XL |
1093 | /// |
1094 | /// # Examples | |
1095 | /// | |
1096 | /// ``` | |
fc512014 XL |
1097 | /// use std::collections::BTreeMap; |
1098 | /// | |
1099 | /// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x*10)).collect(); | |
1100 | /// // Keep only the elements with even-numbered keys. | |
1101 | /// map.retain(|&k, _| k % 2 == 0); | |
1102 | /// assert!(map.into_iter().eq(vec![(0, 0), (2, 20), (4, 40), (6, 60)])); | |
1103 | /// ``` | |
1104 | #[inline] | |
cdc7bbd5 | 1105 | #[stable(feature = "btree_retain", since = "1.53.0")] |
fc512014 XL |
1106 | pub fn retain<F>(&mut self, mut f: F) |
1107 | where | |
5869c6ff | 1108 | K: Ord, |
fc512014 XL |
1109 | F: FnMut(&K, &mut V) -> bool, |
1110 | { | |
fe692bf9 | 1111 | self.extract_if(|k, v| !f(k, v)).for_each(drop); |
fc512014 XL |
1112 | } |
1113 | ||
5e7ed085 | 1114 | /// Moves all elements from `other` into `self`, leaving `other` empty. |
a7813a04 | 1115 | /// |
2b03887a FG |
1116 | /// If a key from `other` is already present in `self`, the respective |
1117 | /// value from `self` will be overwritten with the respective value from `other`. | |
1118 | /// | |
a7813a04 XL |
1119 | /// # Examples |
1120 | /// | |
1121 | /// ``` | |
a7813a04 XL |
1122 | /// use std::collections::BTreeMap; |
1123 | /// | |
1124 | /// let mut a = BTreeMap::new(); | |
1125 | /// a.insert(1, "a"); | |
1126 | /// a.insert(2, "b"); | |
2b03887a | 1127 | /// a.insert(3, "c"); // Note: Key (3) also present in b. |
a7813a04 XL |
1128 | /// |
1129 | /// let mut b = BTreeMap::new(); | |
2b03887a | 1130 | /// b.insert(3, "d"); // Note: Key (3) also present in a. |
a7813a04 XL |
1131 | /// b.insert(4, "e"); |
1132 | /// b.insert(5, "f"); | |
1133 | /// | |
1134 | /// a.append(&mut b); | |
1135 | /// | |
1136 | /// assert_eq!(a.len(), 5); | |
1137 | /// assert_eq!(b.len(), 0); | |
1138 | /// | |
1139 | /// assert_eq!(a[&1], "a"); | |
1140 | /// assert_eq!(a[&2], "b"); | |
2b03887a | 1141 | /// assert_eq!(a[&3], "d"); // Note: "c" has been overwritten. |
a7813a04 XL |
1142 | /// assert_eq!(a[&4], "e"); |
1143 | /// assert_eq!(a[&5], "f"); | |
1144 | /// ``` | |
3157f602 | 1145 | #[stable(feature = "btree_append", since = "1.11.0")] |
5869c6ff XL |
1146 | pub fn append(&mut self, other: &mut Self) |
1147 | where | |
1148 | K: Ord, | |
923072b8 | 1149 | A: Clone, |
5869c6ff | 1150 | { |
a7813a04 | 1151 | // Do we have to append anything at all? |
416331ca | 1152 | if other.is_empty() { |
a7813a04 XL |
1153 | return; |
1154 | } | |
1155 | ||
1156 | // We can just swap `self` and `other` if `self` is empty. | |
416331ca | 1157 | if self.is_empty() { |
a7813a04 XL |
1158 | mem::swap(self, other); |
1159 | return; | |
1160 | } | |
1161 | ||
923072b8 FG |
1162 | let self_iter = mem::replace(self, Self::new_in((*self.alloc).clone())).into_iter(); |
1163 | let other_iter = mem::replace(other, Self::new_in((*self.alloc).clone())).into_iter(); | |
1164 | let root = self.root.get_or_insert_with(|| Root::new((*self.alloc).clone())); | |
1165 | root.append_from_sorted_iters( | |
1166 | self_iter, | |
1167 | other_iter, | |
1168 | &mut self.length, | |
1169 | (*self.alloc).clone(), | |
1170 | ) | |
a7813a04 XL |
1171 | } |
1172 | ||
32a655c1 SL |
1173 | /// Constructs a double-ended iterator over a sub-range of elements in the map. |
1174 | /// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will | |
1175 | /// yield elements from min (inclusive) to max (exclusive). | |
1176 | /// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example | |
1177 | /// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive | |
1178 | /// range from 4 to 10. | |
9346a6ac | 1179 | /// |
8bb4bdeb XL |
1180 | /// # Panics |
1181 | /// | |
1182 | /// Panics if range `start > end`. | |
1183 | /// Panics if range `start == end` and both bounds are `Excluded`. | |
1184 | /// | |
9346a6ac AL |
1185 | /// # Examples |
1186 | /// | |
1187 | /// ``` | |
1188 | /// use std::collections::BTreeMap; | |
0531ce1d | 1189 | /// use std::ops::Bound::Included; |
9346a6ac AL |
1190 | /// |
1191 | /// let mut map = BTreeMap::new(); | |
9cc50fc6 SL |
1192 | /// map.insert(3, "a"); |
1193 | /// map.insert(5, "b"); | |
1194 | /// map.insert(8, "c"); | |
32a655c1 | 1195 | /// for (&key, &value) in map.range((Included(&4), Included(&8))) { |
5e7ed085 | 1196 | /// println!("{key}: {value}"); |
9346a6ac | 1197 | /// } |
32a655c1 | 1198 | /// assert_eq!(Some((&5, &"b")), map.range(4..).next()); |
9346a6ac | 1199 | /// ``` |
8bb4bdeb | 1200 | #[stable(feature = "btree_range", since = "1.17.0")] |
9fa01778 | 1201 | pub fn range<T: ?Sized, R>(&self, range: R) -> Range<'_, K, V> |
dfeec247 XL |
1202 | where |
1203 | T: Ord, | |
5869c6ff | 1204 | K: Borrow<T> + Ord, |
dfeec247 | 1205 | R: RangeBounds<T>, |
9cc50fc6 | 1206 | { |
ba9703b0 | 1207 | if let Some(root) = &self.root { |
6a06907d | 1208 | Range { inner: root.reborrow().range_search(range) } |
ba9703b0 | 1209 | } else { |
6a06907d | 1210 | Range { inner: LeafRange::none() } |
ba9703b0 | 1211 | } |
9cc50fc6 SL |
1212 | } |
1213 | ||
32a655c1 SL |
1214 | /// Constructs a mutable double-ended iterator over a sub-range of elements in the map. |
1215 | /// The simplest way is to use the range syntax `min..max`, thus `range(min..max)` will | |
1216 | /// yield elements from min (inclusive) to max (exclusive). | |
1217 | /// The range may also be entered as `(Bound<T>, Bound<T>)`, so for example | |
1218 | /// `range((Excluded(4), Included(10)))` will yield a left-exclusive, right-inclusive | |
1219 | /// range from 4 to 10. | |
9cc50fc6 | 1220 | /// |
8bb4bdeb XL |
1221 | /// # Panics |
1222 | /// | |
1223 | /// Panics if range `start > end`. | |
1224 | /// Panics if range `start == end` and both bounds are `Excluded`. | |
1225 | /// | |
9cc50fc6 SL |
1226 | /// # Examples |
1227 | /// | |
1228 | /// ``` | |
9cc50fc6 | 1229 | /// use std::collections::BTreeMap; |
9cc50fc6 | 1230 | /// |
5099ac24 FG |
1231 | /// let mut map: BTreeMap<&str, i32> = |
1232 | /// [("Alice", 0), ("Bob", 0), ("Carol", 0), ("Cheryl", 0)].into(); | |
32a655c1 | 1233 | /// for (_, balance) in map.range_mut("B".."Cheryl") { |
9cc50fc6 SL |
1234 | /// *balance += 100; |
1235 | /// } | |
1236 | /// for (name, balance) in &map { | |
5e7ed085 | 1237 | /// println!("{name} => {balance}"); |
9cc50fc6 SL |
1238 | /// } |
1239 | /// ``` | |
8bb4bdeb | 1240 | #[stable(feature = "btree_range", since = "1.17.0")] |
9fa01778 | 1241 | pub fn range_mut<T: ?Sized, R>(&mut self, range: R) -> RangeMut<'_, K, V> |
dfeec247 XL |
1242 | where |
1243 | T: Ord, | |
5869c6ff | 1244 | K: Borrow<T> + Ord, |
dfeec247 | 1245 | R: RangeBounds<T>, |
9cc50fc6 | 1246 | { |
ba9703b0 | 1247 | if let Some(root) = &mut self.root { |
6a06907d | 1248 | RangeMut { inner: root.borrow_valmut().range_search(range), _marker: PhantomData } |
ba9703b0 | 1249 | } else { |
6a06907d | 1250 | RangeMut { inner: LeafRange::none(), _marker: PhantomData } |
ba9703b0 | 1251 | } |
9cc50fc6 SL |
1252 | } |
1253 | ||
1254 | /// Gets the given key's corresponding entry in the map for in-place manipulation. | |
1255 | /// | |
1256 | /// # Examples | |
1257 | /// | |
1258 | /// ``` | |
1259 | /// use std::collections::BTreeMap; | |
1260 | /// | |
1261 | /// let mut count: BTreeMap<&str, usize> = BTreeMap::new(); | |
1262 | /// | |
1263 | /// // count the number of occurrences of letters in the vec | |
5099ac24 | 1264 | /// for x in ["a", "b", "a", "c", "a", "b"] { |
923072b8 | 1265 | /// count.entry(x).and_modify(|curr| *curr += 1).or_insert(1); |
9cc50fc6 SL |
1266 | /// } |
1267 | /// | |
1268 | /// assert_eq!(count["a"], 3); | |
923072b8 FG |
1269 | /// assert_eq!(count["b"], 2); |
1270 | /// assert_eq!(count["c"], 1); | |
9cc50fc6 SL |
1271 | /// ``` |
1272 | #[stable(feature = "rust1", since = "1.0.0")] | |
923072b8 | 1273 | pub fn entry(&mut self, key: K) -> Entry<'_, K, V, A> |
5869c6ff XL |
1274 | where |
1275 | K: Ord, | |
1276 | { | |
1b1a35ee | 1277 | let (map, dormant_map) = DormantMutRef::new(self); |
5e7ed085 | 1278 | match map.root { |
923072b8 FG |
1279 | None => Vacant(VacantEntry { |
1280 | key, | |
1281 | handle: None, | |
1282 | dormant_map, | |
1283 | alloc: (*map.alloc).clone(), | |
1284 | _marker: PhantomData, | |
1285 | }), | |
5e7ed085 | 1286 | Some(ref mut root) => match root.borrow_mut().search_tree(&key) { |
923072b8 FG |
1287 | Found(handle) => Occupied(OccupiedEntry { |
1288 | handle, | |
1289 | dormant_map, | |
1290 | alloc: (*map.alloc).clone(), | |
1291 | _marker: PhantomData, | |
1292 | }), | |
5e7ed085 FG |
1293 | GoDown(handle) => Vacant(VacantEntry { |
1294 | key, | |
1295 | handle: Some(handle), | |
1296 | dormant_map, | |
923072b8 | 1297 | alloc: (*map.alloc).clone(), |
5e7ed085 FG |
1298 | _marker: PhantomData, |
1299 | }), | |
1300 | }, | |
9346a6ac | 1301 | } |
85aaf69f | 1302 | } |
a7813a04 | 1303 | |
3157f602 XL |
1304 | /// Splits the collection into two at the given key. Returns everything after the given key, |
1305 | /// including the key. | |
1306 | /// | |
1307 | /// # Examples | |
1308 | /// | |
3157f602 XL |
1309 | /// ``` |
1310 | /// use std::collections::BTreeMap; | |
1311 | /// | |
1312 | /// let mut a = BTreeMap::new(); | |
1313 | /// a.insert(1, "a"); | |
1314 | /// a.insert(2, "b"); | |
1315 | /// a.insert(3, "c"); | |
1316 | /// a.insert(17, "d"); | |
1317 | /// a.insert(41, "e"); | |
1318 | /// | |
1319 | /// let b = a.split_off(&3); | |
1320 | /// | |
1321 | /// assert_eq!(a.len(), 2); | |
1322 | /// assert_eq!(b.len(), 3); | |
1323 | /// | |
1324 | /// assert_eq!(a[&1], "a"); | |
1325 | /// assert_eq!(a[&2], "b"); | |
1326 | /// | |
1327 | /// assert_eq!(b[&3], "c"); | |
1328 | /// assert_eq!(b[&17], "d"); | |
1329 | /// assert_eq!(b[&41], "e"); | |
1330 | /// ``` | |
1331 | #[stable(feature = "btree_split_off", since = "1.11.0")] | |
1332 | pub fn split_off<Q: ?Sized + Ord>(&mut self, key: &Q) -> Self | |
dfeec247 | 1333 | where |
5869c6ff | 1334 | K: Borrow<Q> + Ord, |
923072b8 | 1335 | A: Clone, |
3157f602 XL |
1336 | { |
1337 | if self.is_empty() { | |
923072b8 | 1338 | return Self::new_in((*self.alloc).clone()); |
3157f602 XL |
1339 | } |
1340 | ||
1341 | let total_num = self.len(); | |
3dfed10e | 1342 | let left_root = self.root.as_mut().unwrap(); // unwrap succeeds because not empty |
3157f602 | 1343 | |
923072b8 | 1344 | let right_root = left_root.split_off(key, (*self.alloc).clone()); |
3157f602 | 1345 | |
6a06907d XL |
1346 | let (new_left_len, right_len) = Root::calc_split_length(total_num, &left_root, &right_root); |
1347 | self.length = new_left_len; | |
3157f602 | 1348 | |
064997fb FG |
1349 | BTreeMap { |
1350 | root: Some(right_root), | |
1351 | length: right_len, | |
1352 | alloc: self.alloc.clone(), | |
1353 | _marker: PhantomData, | |
1354 | } | |
3157f602 XL |
1355 | } |
1356 | ||
6a06907d XL |
1357 | /// Creates an iterator that visits all elements (key-value pairs) in |
1358 | /// ascending key order and uses a closure to determine if an element should | |
1359 | /// be removed. If the closure returns `true`, the element is removed from | |
1360 | /// the map and yielded. If the closure returns `false`, or panics, the | |
1361 | /// element remains in the map and will not be yielded. | |
ba9703b0 | 1362 | /// |
6a06907d XL |
1363 | /// The iterator also lets you mutate the value of each element in the |
1364 | /// closure, regardless of whether you choose to keep or remove it. | |
ba9703b0 | 1365 | /// |
fe692bf9 FG |
1366 | /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating |
1367 | /// or the iteration short-circuits, then the remaining elements will be retained. | |
1368 | /// Use [`retain`] with a negated predicate if you do not need the returned iterator. | |
ba9703b0 | 1369 | /// |
fe692bf9 | 1370 | /// [`retain`]: BTreeMap::retain |
ba9703b0 XL |
1371 | /// |
1372 | /// # Examples | |
1373 | /// | |
1374 | /// Splitting a map into even and odd keys, reusing the original map: | |
1375 | /// | |
1376 | /// ``` | |
fe692bf9 | 1377 | /// #![feature(btree_extract_if)] |
ba9703b0 XL |
1378 | /// use std::collections::BTreeMap; |
1379 | /// | |
1380 | /// let mut map: BTreeMap<i32, i32> = (0..8).map(|x| (x, x)).collect(); | |
fe692bf9 | 1381 | /// let evens: BTreeMap<_, _> = map.extract_if(|k, _v| k % 2 == 0).collect(); |
ba9703b0 | 1382 | /// let odds = map; |
5099ac24 FG |
1383 | /// assert_eq!(evens.keys().copied().collect::<Vec<_>>(), [0, 2, 4, 6]); |
1384 | /// assert_eq!(odds.keys().copied().collect::<Vec<_>>(), [1, 3, 5, 7]); | |
ba9703b0 | 1385 | /// ``` |
fe692bf9 FG |
1386 | #[unstable(feature = "btree_extract_if", issue = "70530")] |
1387 | pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, K, V, F, A> | |
ba9703b0 | 1388 | where |
5869c6ff | 1389 | K: Ord, |
ba9703b0 XL |
1390 | F: FnMut(&K, &mut V) -> bool, |
1391 | { | |
fe692bf9 FG |
1392 | let (inner, alloc) = self.extract_if_inner(); |
1393 | ExtractIf { pred, inner, alloc } | |
ba9703b0 | 1394 | } |
3dfed10e | 1395 | |
fe692bf9 | 1396 | pub(super) fn extract_if_inner(&mut self) -> (ExtractIfInner<'_, K, V>, A) |
5869c6ff XL |
1397 | where |
1398 | K: Ord, | |
1399 | { | |
1b1a35ee XL |
1400 | if let Some(root) = self.root.as_mut() { |
1401 | let (root, dormant_root) = DormantMutRef::new(root); | |
fc512014 | 1402 | let front = root.borrow_mut().first_leaf_edge(); |
923072b8 | 1403 | ( |
fe692bf9 | 1404 | ExtractIfInner { |
923072b8 FG |
1405 | length: &mut self.length, |
1406 | dormant_root: Some(dormant_root), | |
1407 | cur_leaf_edge: Some(front), | |
1408 | }, | |
1409 | (*self.alloc).clone(), | |
1410 | ) | |
1b1a35ee | 1411 | } else { |
923072b8 | 1412 | ( |
fe692bf9 | 1413 | ExtractIfInner { |
923072b8 FG |
1414 | length: &mut self.length, |
1415 | dormant_root: None, | |
1416 | cur_leaf_edge: None, | |
1417 | }, | |
1418 | (*self.alloc).clone(), | |
1419 | ) | |
1b1a35ee | 1420 | } |
ba9703b0 XL |
1421 | } |
1422 | ||
3dfed10e XL |
1423 | /// Creates a consuming iterator visiting all the keys, in sorted order. |
1424 | /// The map cannot be used after calling this. | |
1425 | /// The iterator element type is `K`. | |
1426 | /// | |
1427 | /// # Examples | |
1428 | /// | |
1429 | /// ``` | |
3dfed10e XL |
1430 | /// use std::collections::BTreeMap; |
1431 | /// | |
1432 | /// let mut a = BTreeMap::new(); | |
1433 | /// a.insert(2, "b"); | |
1434 | /// a.insert(1, "a"); | |
1435 | /// | |
1436 | /// let keys: Vec<i32> = a.into_keys().collect(); | |
1437 | /// assert_eq!(keys, [1, 2]); | |
1438 | /// ``` | |
1439 | #[inline] | |
17df50a5 | 1440 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 1441 | pub fn into_keys(self) -> IntoKeys<K, V, A> { |
3dfed10e | 1442 | IntoKeys { inner: self.into_iter() } |
3157f602 XL |
1443 | } |
1444 | ||
3dfed10e XL |
1445 | /// Creates a consuming iterator visiting all the values, in order by key. |
1446 | /// The map cannot be used after calling this. | |
1447 | /// The iterator element type is `V`. | |
1448 | /// | |
1449 | /// # Examples | |
1450 | /// | |
1451 | /// ``` | |
3dfed10e XL |
1452 | /// use std::collections::BTreeMap; |
1453 | /// | |
1454 | /// let mut a = BTreeMap::new(); | |
1455 | /// a.insert(1, "hello"); | |
1456 | /// a.insert(2, "goodbye"); | |
1457 | /// | |
1458 | /// let values: Vec<&str> = a.into_values().collect(); | |
1459 | /// assert_eq!(values, ["hello", "goodbye"]); | |
1460 | /// ``` | |
1461 | #[inline] | |
17df50a5 | 1462 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 1463 | pub fn into_values(self) -> IntoValues<K, V, A> { |
3dfed10e | 1464 | IntoValues { inner: self.into_iter() } |
3157f602 | 1465 | } |
c295e0f8 XL |
1466 | |
1467 | /// Makes a `BTreeMap` from a sorted iterator. | |
923072b8 | 1468 | pub(crate) fn bulk_build_from_sorted_iter<I>(iter: I, alloc: A) -> Self |
c295e0f8 XL |
1469 | where |
1470 | K: Ord, | |
a2a8927a | 1471 | I: IntoIterator<Item = (K, V)>, |
c295e0f8 | 1472 | { |
923072b8 | 1473 | let mut root = Root::new(alloc.clone()); |
c295e0f8 | 1474 | let mut length = 0; |
923072b8 | 1475 | root.bulk_push(DedupSortedIter::new(iter.into_iter()), &mut length, alloc.clone()); |
064997fb | 1476 | BTreeMap { root: Some(root), length, alloc: ManuallyDrop::new(alloc), _marker: PhantomData } |
c295e0f8 | 1477 | } |
85aaf69f SL |
1478 | } |
1479 | ||
c30ab7b3 | 1480 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1481 | impl<'a, K, V, A: Allocator + Clone> IntoIterator for &'a BTreeMap<K, V, A> { |
85aaf69f SL |
1482 | type Item = (&'a K, &'a V); |
1483 | type IntoIter = Iter<'a, K, V>; | |
1484 | ||
1485 | fn into_iter(self) -> Iter<'a, K, V> { | |
1486 | self.iter() | |
1487 | } | |
1488 | } | |
1489 | ||
c30ab7b3 | 1490 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1491 | impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> { |
1492 | type Item = (&'a K, &'a V); | |
85aaf69f | 1493 | |
9cc50fc6 SL |
1494 | fn next(&mut self) -> Option<(&'a K, &'a V)> { |
1495 | if self.length == 0 { | |
1496 | None | |
1497 | } else { | |
1498 | self.length -= 1; | |
94222f64 | 1499 | Some(unsafe { self.range.next_unchecked() }) |
9cc50fc6 | 1500 | } |
85aaf69f | 1501 | } |
85aaf69f | 1502 | |
9cc50fc6 SL |
1503 | fn size_hint(&self) -> (usize, Option<usize>) { |
1504 | (self.length, Some(self.length)) | |
1505 | } | |
416331ca XL |
1506 | |
1507 | fn last(mut self) -> Option<(&'a K, &'a V)> { | |
1508 | self.next_back() | |
1509 | } | |
f035d41b | 1510 | |
49aad941 FG |
1511 | fn min(mut self) -> Option<(&'a K, &'a V)> |
1512 | where | |
1513 | (&'a K, &'a V): Ord, | |
1514 | { | |
f035d41b XL |
1515 | self.next() |
1516 | } | |
1517 | ||
49aad941 FG |
1518 | fn max(mut self) -> Option<(&'a K, &'a V)> |
1519 | where | |
1520 | (&'a K, &'a V): Ord, | |
1521 | { | |
f035d41b XL |
1522 | self.next_back() |
1523 | } | |
1a4d82fc JJ |
1524 | } |
1525 | ||
0531ce1d | 1526 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1527 | impl<K, V> FusedIterator for Iter<'_, K, V> {} |
9e0c209e | 1528 | |
c30ab7b3 | 1529 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1530 | impl<'a, K: 'a, V: 'a> DoubleEndedIterator for Iter<'a, K, V> { |
1531 | fn next_back(&mut self) -> Option<(&'a K, &'a V)> { | |
1532 | if self.length == 0 { | |
1533 | None | |
1534 | } else { | |
1535 | self.length -= 1; | |
94222f64 | 1536 | Some(unsafe { self.range.next_back_unchecked() }) |
85aaf69f SL |
1537 | } |
1538 | } | |
9cc50fc6 | 1539 | } |
85aaf69f | 1540 | |
c30ab7b3 | 1541 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1542 | impl<K, V> ExactSizeIterator for Iter<'_, K, V> { |
3157f602 XL |
1543 | fn len(&self) -> usize { |
1544 | self.length | |
1545 | } | |
9cc50fc6 | 1546 | } |
1a4d82fc | 1547 | |
c30ab7b3 | 1548 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 XL |
1549 | impl<K, V> Clone for Iter<'_, K, V> { |
1550 | fn clone(&self) -> Self { | |
dfeec247 | 1551 | Iter { range: self.range.clone(), length: self.length } |
1a4d82fc | 1552 | } |
9cc50fc6 | 1553 | } |
1a4d82fc | 1554 | |
c30ab7b3 | 1555 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1556 | impl<'a, K, V, A: Allocator + Clone> IntoIterator for &'a mut BTreeMap<K, V, A> { |
9cc50fc6 SL |
1557 | type Item = (&'a K, &'a mut V); |
1558 | type IntoIter = IterMut<'a, K, V>; | |
1559 | ||
1560 | fn into_iter(self) -> IterMut<'a, K, V> { | |
1561 | self.iter_mut() | |
1a4d82fc | 1562 | } |
9cc50fc6 | 1563 | } |
1a4d82fc | 1564 | |
c30ab7b3 | 1565 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1566 | impl<'a, K, V> Iterator for IterMut<'a, K, V> { |
9cc50fc6 | 1567 | type Item = (&'a K, &'a mut V); |
1a4d82fc | 1568 | |
9cc50fc6 SL |
1569 | fn next(&mut self) -> Option<(&'a K, &'a mut V)> { |
1570 | if self.length == 0 { | |
1571 | None | |
1572 | } else { | |
1573 | self.length -= 1; | |
94222f64 | 1574 | Some(unsafe { self.range.next_unchecked() }) |
9cc50fc6 | 1575 | } |
1a4d82fc JJ |
1576 | } |
1577 | ||
9cc50fc6 SL |
1578 | fn size_hint(&self) -> (usize, Option<usize>) { |
1579 | (self.length, Some(self.length)) | |
1a4d82fc | 1580 | } |
416331ca XL |
1581 | |
1582 | fn last(mut self) -> Option<(&'a K, &'a mut V)> { | |
1583 | self.next_back() | |
1584 | } | |
f035d41b | 1585 | |
49aad941 FG |
1586 | fn min(mut self) -> Option<(&'a K, &'a mut V)> |
1587 | where | |
1588 | (&'a K, &'a mut V): Ord, | |
1589 | { | |
f035d41b XL |
1590 | self.next() |
1591 | } | |
1592 | ||
49aad941 FG |
1593 | fn max(mut self) -> Option<(&'a K, &'a mut V)> |
1594 | where | |
1595 | (&'a K, &'a mut V): Ord, | |
1596 | { | |
f035d41b XL |
1597 | self.next_back() |
1598 | } | |
9cc50fc6 | 1599 | } |
1a4d82fc | 1600 | |
c30ab7b3 | 1601 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1602 | impl<'a, K, V> DoubleEndedIterator for IterMut<'a, K, V> { |
9cc50fc6 SL |
1603 | fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> { |
1604 | if self.length == 0 { | |
1605 | None | |
1606 | } else { | |
1607 | self.length -= 1; | |
94222f64 | 1608 | Some(unsafe { self.range.next_back_unchecked() }) |
9cc50fc6 | 1609 | } |
1a4d82fc | 1610 | } |
9cc50fc6 | 1611 | } |
1a4d82fc | 1612 | |
c30ab7b3 | 1613 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1614 | impl<K, V> ExactSizeIterator for IterMut<'_, K, V> { |
3157f602 XL |
1615 | fn len(&self) -> usize { |
1616 | self.length | |
1617 | } | |
9cc50fc6 | 1618 | } |
1a4d82fc | 1619 | |
0531ce1d | 1620 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1621 | impl<K, V> FusedIterator for IterMut<'_, K, V> {} |
9e0c209e | 1622 | |
1b1a35ee XL |
1623 | impl<'a, K, V> IterMut<'a, K, V> { |
1624 | /// Returns an iterator of references over the remaining items. | |
1625 | #[inline] | |
1626 | pub(super) fn iter(&self) -> Iter<'_, K, V> { | |
94222f64 | 1627 | Iter { range: self.range.reborrow(), length: self.length } |
1b1a35ee XL |
1628 | } |
1629 | } | |
1630 | ||
c30ab7b3 | 1631 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1632 | impl<K, V, A: Allocator + Clone> IntoIterator for BTreeMap<K, V, A> { |
9cc50fc6 | 1633 | type Item = (K, V); |
923072b8 | 1634 | type IntoIter = IntoIter<K, V, A>; |
1a4d82fc | 1635 | |
923072b8 | 1636 | fn into_iter(self) -> IntoIter<K, V, A> { |
ba9703b0 | 1637 | let mut me = ManuallyDrop::new(self); |
f9f354fc | 1638 | if let Some(root) = me.root.take() { |
6a06907d | 1639 | let full_range = root.into_dying().full_range(); |
f9f354fc | 1640 | |
923072b8 FG |
1641 | IntoIter { |
1642 | range: full_range, | |
1643 | length: me.length, | |
1644 | alloc: unsafe { ManuallyDrop::take(&mut me.alloc) }, | |
1645 | } | |
ba9703b0 | 1646 | } else { |
923072b8 FG |
1647 | IntoIter { |
1648 | range: LazyLeafRange::none(), | |
1649 | length: 0, | |
1650 | alloc: unsafe { ManuallyDrop::take(&mut me.alloc) }, | |
1651 | } | |
ba9703b0 | 1652 | } |
1a4d82fc | 1653 | } |
9cc50fc6 | 1654 | } |
1a4d82fc | 1655 | |
94222f64 | 1656 | #[stable(feature = "btree_drop", since = "1.7.0")] |
923072b8 | 1657 | impl<K, V, A: Allocator + Clone> Drop for IntoIter<K, V, A> { |
9cc50fc6 | 1658 | fn drop(&mut self) { |
923072b8 | 1659 | struct DropGuard<'a, K, V, A: Allocator + Clone>(&'a mut IntoIter<K, V, A>); |
74b04a01 | 1660 | |
923072b8 | 1661 | impl<'a, K, V, A: Allocator + Clone> Drop for DropGuard<'a, K, V, A> { |
74b04a01 XL |
1662 | fn drop(&mut self) { |
1663 | // Continue the same loop we perform below. This only runs when unwinding, so we | |
1664 | // don't have to care about panics this time (they'll abort). | |
94222f64 XL |
1665 | while let Some(kv) = self.0.dying_next() { |
1666 | // SAFETY: we consume the dying handle immediately. | |
1667 | unsafe { kv.drop_key_val() }; | |
17df50a5 | 1668 | } |
74b04a01 XL |
1669 | } |
1670 | } | |
1671 | ||
94222f64 | 1672 | while let Some(kv) = self.dying_next() { |
74b04a01 | 1673 | let guard = DropGuard(self); |
94222f64 XL |
1674 | // SAFETY: we don't touch the tree before consuming the dying handle. |
1675 | unsafe { kv.drop_key_val() }; | |
74b04a01 XL |
1676 | mem::forget(guard); |
1677 | } | |
6a06907d XL |
1678 | } |
1679 | } | |
74b04a01 | 1680 | |
923072b8 | 1681 | impl<K, V, A: Allocator + Clone> IntoIter<K, V, A> { |
94222f64 XL |
1682 | /// Core of a `next` method returning a dying KV handle, |
1683 | /// invalidated by further calls to this function and some others. | |
1684 | fn dying_next( | |
1685 | &mut self, | |
1686 | ) -> Option<Handle<NodeRef<marker::Dying, K, V, marker::LeafOrInternal>, marker::KV>> { | |
1687 | if self.length == 0 { | |
923072b8 | 1688 | self.range.deallocating_end(self.alloc.clone()); |
94222f64 XL |
1689 | None |
1690 | } else { | |
1691 | self.length -= 1; | |
923072b8 | 1692 | Some(unsafe { self.range.deallocating_next_unchecked(self.alloc.clone()) }) |
94222f64 XL |
1693 | } |
1694 | } | |
1695 | ||
1696 | /// Core of a `next_back` method returning a dying KV handle, | |
1697 | /// invalidated by further calls to this function and some others. | |
1698 | fn dying_next_back( | |
1699 | &mut self, | |
1700 | ) -> Option<Handle<NodeRef<marker::Dying, K, V, marker::LeafOrInternal>, marker::KV>> { | |
1701 | if self.length == 0 { | |
923072b8 | 1702 | self.range.deallocating_end(self.alloc.clone()); |
94222f64 XL |
1703 | None |
1704 | } else { | |
1705 | self.length -= 1; | |
923072b8 | 1706 | Some(unsafe { self.range.deallocating_next_back_unchecked(self.alloc.clone()) }) |
1a4d82fc JJ |
1707 | } |
1708 | } | |
9cc50fc6 | 1709 | } |
1a4d82fc | 1710 | |
c30ab7b3 | 1711 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1712 | impl<K, V, A: Allocator + Clone> Iterator for IntoIter<K, V, A> { |
9cc50fc6 | 1713 | type Item = (K, V); |
1a4d82fc | 1714 | |
9cc50fc6 | 1715 | fn next(&mut self) -> Option<(K, V)> { |
94222f64 XL |
1716 | // SAFETY: we consume the dying handle immediately. |
1717 | self.dying_next().map(unsafe { |kv| kv.into_key_val() }) | |
1a4d82fc JJ |
1718 | } |
1719 | ||
9cc50fc6 SL |
1720 | fn size_hint(&self) -> (usize, Option<usize>) { |
1721 | (self.length, Some(self.length)) | |
1722 | } | |
1723 | } | |
1724 | ||
c30ab7b3 | 1725 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1726 | impl<K, V, A: Allocator + Clone> DoubleEndedIterator for IntoIter<K, V, A> { |
9cc50fc6 | 1727 | fn next_back(&mut self) -> Option<(K, V)> { |
94222f64 XL |
1728 | // SAFETY: we consume the dying handle immediately. |
1729 | self.dying_next_back().map(unsafe { |kv| kv.into_key_val() }) | |
1a4d82fc JJ |
1730 | } |
1731 | } | |
1732 | ||
c30ab7b3 | 1733 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 1734 | impl<K, V, A: Allocator + Clone> ExactSizeIterator for IntoIter<K, V, A> { |
3157f602 XL |
1735 | fn len(&self) -> usize { |
1736 | self.length | |
1737 | } | |
1a4d82fc JJ |
1738 | } |
1739 | ||
0531ce1d | 1740 | #[stable(feature = "fused", since = "1.26.0")] |
923072b8 | 1741 | impl<K, V, A: Allocator + Clone> FusedIterator for IntoIter<K, V, A> {} |
9e0c209e | 1742 | |
c30ab7b3 | 1743 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1744 | impl<'a, K, V> Iterator for Keys<'a, K, V> { |
1745 | type Item = &'a K; | |
1746 | ||
1747 | fn next(&mut self) -> Option<&'a K> { | |
1748 | self.inner.next().map(|(k, _)| k) | |
1a4d82fc | 1749 | } |
1a4d82fc | 1750 | |
9cc50fc6 SL |
1751 | fn size_hint(&self) -> (usize, Option<usize>) { |
1752 | self.inner.size_hint() | |
62682a34 | 1753 | } |
416331ca XL |
1754 | |
1755 | fn last(mut self) -> Option<&'a K> { | |
1756 | self.next_back() | |
1757 | } | |
f035d41b | 1758 | |
49aad941 FG |
1759 | fn min(mut self) -> Option<&'a K> |
1760 | where | |
1761 | &'a K: Ord, | |
1762 | { | |
f035d41b XL |
1763 | self.next() |
1764 | } | |
1765 | ||
49aad941 FG |
1766 | fn max(mut self) -> Option<&'a K> |
1767 | where | |
1768 | &'a K: Ord, | |
1769 | { | |
f035d41b XL |
1770 | self.next_back() |
1771 | } | |
62682a34 SL |
1772 | } |
1773 | ||
c30ab7b3 | 1774 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1775 | impl<'a, K, V> DoubleEndedIterator for Keys<'a, K, V> { |
1776 | fn next_back(&mut self) -> Option<&'a K> { | |
1777 | self.inner.next_back().map(|(k, _)| k) | |
1a4d82fc JJ |
1778 | } |
1779 | } | |
1780 | ||
c30ab7b3 | 1781 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1782 | impl<K, V> ExactSizeIterator for Keys<'_, K, V> { |
9cc50fc6 SL |
1783 | fn len(&self) -> usize { |
1784 | self.inner.len() | |
1a4d82fc JJ |
1785 | } |
1786 | } | |
1787 | ||
0531ce1d | 1788 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1789 | impl<K, V> FusedIterator for Keys<'_, K, V> {} |
9e0c209e | 1790 | |
c30ab7b3 | 1791 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 XL |
1792 | impl<K, V> Clone for Keys<'_, K, V> { |
1793 | fn clone(&self) -> Self { | |
3157f602 | 1794 | Keys { inner: self.inner.clone() } |
1a4d82fc JJ |
1795 | } |
1796 | } | |
1797 | ||
353b0b11 FG |
1798 | #[stable(feature = "default_iters", since = "1.70.0")] |
1799 | impl<K, V> Default for Keys<'_, K, V> { | |
1800 | /// Creates an empty `btree_map::Keys`. | |
1801 | /// | |
1802 | /// ``` | |
1803 | /// # use std::collections::btree_map; | |
1804 | /// let iter: btree_map::Keys<'_, u8, u8> = Default::default(); | |
1805 | /// assert_eq!(iter.len(), 0); | |
1806 | /// ``` | |
1807 | fn default() -> Self { | |
1808 | Keys { inner: Default::default() } | |
1809 | } | |
1810 | } | |
1811 | ||
c30ab7b3 | 1812 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1813 | impl<'a, K, V> Iterator for Values<'a, K, V> { |
1814 | type Item = &'a V; | |
1a4d82fc | 1815 | |
9cc50fc6 SL |
1816 | fn next(&mut self) -> Option<&'a V> { |
1817 | self.inner.next().map(|(_, v)| v) | |
1a4d82fc | 1818 | } |
1a4d82fc | 1819 | |
9cc50fc6 SL |
1820 | fn size_hint(&self) -> (usize, Option<usize>) { |
1821 | self.inner.size_hint() | |
1a4d82fc | 1822 | } |
416331ca XL |
1823 | |
1824 | fn last(mut self) -> Option<&'a V> { | |
1825 | self.next_back() | |
1826 | } | |
1a4d82fc JJ |
1827 | } |
1828 | ||
c30ab7b3 | 1829 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 SL |
1830 | impl<'a, K, V> DoubleEndedIterator for Values<'a, K, V> { |
1831 | fn next_back(&mut self) -> Option<&'a V> { | |
1832 | self.inner.next_back().map(|(_, v)| v) | |
1a4d82fc JJ |
1833 | } |
1834 | } | |
1835 | ||
c30ab7b3 | 1836 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1837 | impl<K, V> ExactSizeIterator for Values<'_, K, V> { |
9cc50fc6 SL |
1838 | fn len(&self) -> usize { |
1839 | self.inner.len() | |
1a4d82fc JJ |
1840 | } |
1841 | } | |
1842 | ||
0531ce1d | 1843 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1844 | impl<K, V> FusedIterator for Values<'_, K, V> {} |
9e0c209e | 1845 | |
c30ab7b3 | 1846 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 XL |
1847 | impl<K, V> Clone for Values<'_, K, V> { |
1848 | fn clone(&self) -> Self { | |
3157f602 | 1849 | Values { inner: self.inner.clone() } |
1a4d82fc JJ |
1850 | } |
1851 | } | |
1852 | ||
353b0b11 FG |
1853 | #[stable(feature = "default_iters", since = "1.70.0")] |
1854 | impl<K, V> Default for Values<'_, K, V> { | |
1855 | /// Creates an empty `btree_map::Values`. | |
1856 | /// | |
1857 | /// ``` | |
1858 | /// # use std::collections::btree_map; | |
1859 | /// let iter: btree_map::Values<'_, u8, u8> = Default::default(); | |
1860 | /// assert_eq!(iter.len(), 0); | |
1861 | /// ``` | |
1862 | fn default() -> Self { | |
1863 | Values { inner: Default::default() } | |
1864 | } | |
1865 | } | |
1866 | ||
fe692bf9 FG |
1867 | /// An iterator produced by calling `extract_if` on BTreeMap. |
1868 | #[unstable(feature = "btree_extract_if", issue = "70530")] | |
1869 | #[must_use = "iterators are lazy and do nothing unless consumed"] | |
1870 | pub struct ExtractIf< | |
923072b8 FG |
1871 | 'a, |
1872 | K, | |
1873 | V, | |
1874 | F, | |
1875 | #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + Clone = Global, | |
1876 | > where | |
ba9703b0 XL |
1877 | F: 'a + FnMut(&K, &mut V) -> bool, |
1878 | { | |
1879 | pred: F, | |
fe692bf9 | 1880 | inner: ExtractIfInner<'a, K, V>, |
923072b8 FG |
1881 | /// The BTreeMap will outlive this IntoIter so we don't care about drop order for `alloc`. |
1882 | alloc: A, | |
ba9703b0 | 1883 | } |
fe692bf9 FG |
1884 | /// Most of the implementation of ExtractIf are generic over the type |
1885 | /// of the predicate, thus also serving for BTreeSet::ExtractIf. | |
1886 | pub(super) struct ExtractIfInner<'a, K, V> { | |
29967ef6 | 1887 | /// Reference to the length field in the borrowed map, updated live. |
ba9703b0 | 1888 | length: &'a mut usize, |
fc512014 | 1889 | /// Buried reference to the root field in the borrowed map. |
29967ef6 | 1890 | /// Wrapped in `Option` to allow drop handler to `take` it. |
fc512014 | 1891 | dormant_root: Option<DormantMutRef<'a, Root<K, V>>>, |
29967ef6 XL |
1892 | /// Contains a leaf edge preceding the next element to be returned, or the last leaf edge. |
1893 | /// Empty if the map has no root, if iteration went beyond the last leaf edge, | |
1894 | /// or if a panic occurred in the predicate. | |
ba9703b0 XL |
1895 | cur_leaf_edge: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::Leaf>, marker::Edge>>, |
1896 | } | |
1897 | ||
fe692bf9 FG |
1898 | #[unstable(feature = "btree_extract_if", issue = "70530")] |
1899 | impl<K, V, F> fmt::Debug for ExtractIf<'_, K, V, F> | |
ba9703b0 XL |
1900 | where |
1901 | K: fmt::Debug, | |
1902 | V: fmt::Debug, | |
1903 | F: FnMut(&K, &mut V) -> bool, | |
1904 | { | |
1905 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
fe692bf9 | 1906 | f.debug_tuple("ExtractIf").field(&self.inner.peek()).finish() |
ba9703b0 XL |
1907 | } |
1908 | } | |
1909 | ||
fe692bf9 FG |
1910 | #[unstable(feature = "btree_extract_if", issue = "70530")] |
1911 | impl<K, V, F, A: Allocator + Clone> Iterator for ExtractIf<'_, K, V, F, A> | |
ba9703b0 XL |
1912 | where |
1913 | F: FnMut(&K, &mut V) -> bool, | |
1914 | { | |
1915 | type Item = (K, V); | |
1916 | ||
1917 | fn next(&mut self) -> Option<(K, V)> { | |
923072b8 | 1918 | self.inner.next(&mut self.pred, self.alloc.clone()) |
ba9703b0 XL |
1919 | } |
1920 | ||
1921 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1922 | self.inner.size_hint() | |
1923 | } | |
1924 | } | |
1925 | ||
fe692bf9 | 1926 | impl<'a, K, V> ExtractIfInner<'a, K, V> { |
ba9703b0 XL |
1927 | /// Allow Debug implementations to predict the next element. |
1928 | pub(super) fn peek(&self) -> Option<(&K, &V)> { | |
1929 | let edge = self.cur_leaf_edge.as_ref()?; | |
1b1a35ee | 1930 | edge.reborrow().next_kv().ok().map(Handle::into_kv) |
ba9703b0 XL |
1931 | } |
1932 | ||
fe692bf9 | 1933 | /// Implementation of a typical `ExtractIf::next` method, given the predicate. |
923072b8 | 1934 | pub(super) fn next<F, A: Allocator + Clone>(&mut self, pred: &mut F, alloc: A) -> Option<(K, V)> |
ba9703b0 XL |
1935 | where |
1936 | F: FnMut(&K, &mut V) -> bool, | |
1937 | { | |
3dfed10e | 1938 | while let Ok(mut kv) = self.cur_leaf_edge.take()?.next_kv() { |
ba9703b0 XL |
1939 | let (k, v) = kv.kv_mut(); |
1940 | if pred(k, v) { | |
1941 | *self.length -= 1; | |
923072b8 FG |
1942 | let (kv, pos) = kv.remove_kv_tracking( |
1943 | || { | |
1944 | // SAFETY: we will touch the root in a way that will not | |
1945 | // invalidate the position returned. | |
1946 | let root = unsafe { self.dormant_root.take().unwrap().awaken() }; | |
1947 | root.pop_internal_level(alloc.clone()); | |
1948 | self.dormant_root = Some(DormantMutRef::new(root).1); | |
1949 | }, | |
1950 | alloc.clone(), | |
1951 | ); | |
3dfed10e XL |
1952 | self.cur_leaf_edge = Some(pos); |
1953 | return Some(kv); | |
ba9703b0 XL |
1954 | } |
1955 | self.cur_leaf_edge = Some(kv.next_leaf_edge()); | |
1956 | } | |
1957 | None | |
1958 | } | |
1959 | ||
fe692bf9 | 1960 | /// Implementation of a typical `ExtractIf::size_hint` method. |
ba9703b0 | 1961 | pub(super) fn size_hint(&self) -> (usize, Option<usize>) { |
29967ef6 XL |
1962 | // In most of the btree iterators, `self.length` is the number of elements |
1963 | // yet to be visited. Here, it includes elements that were visited and that | |
c295e0f8 XL |
1964 | // the predicate decided not to drain. Making this upper bound more tight |
1965 | // during iteration would require an extra field. | |
ba9703b0 XL |
1966 | (0, Some(*self.length)) |
1967 | } | |
1968 | } | |
1969 | ||
fe692bf9 FG |
1970 | #[unstable(feature = "btree_extract_if", issue = "70530")] |
1971 | impl<K, V, F> FusedIterator for ExtractIf<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {} | |
ba9703b0 | 1972 | |
cc61c64b | 1973 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 SL |
1974 | impl<'a, K, V> Iterator for Range<'a, K, V> { |
1975 | type Item = (&'a K, &'a V); | |
1a4d82fc | 1976 | |
9cc50fc6 | 1977 | fn next(&mut self) -> Option<(&'a K, &'a V)> { |
136023e0 | 1978 | self.inner.next_checked() |
1a4d82fc | 1979 | } |
416331ca XL |
1980 | |
1981 | fn last(mut self) -> Option<(&'a K, &'a V)> { | |
1982 | self.next_back() | |
1983 | } | |
f035d41b | 1984 | |
49aad941 FG |
1985 | fn min(mut self) -> Option<(&'a K, &'a V)> |
1986 | where | |
1987 | (&'a K, &'a V): Ord, | |
1988 | { | |
f035d41b XL |
1989 | self.next() |
1990 | } | |
1991 | ||
49aad941 FG |
1992 | fn max(mut self) -> Option<(&'a K, &'a V)> |
1993 | where | |
1994 | (&'a K, &'a V): Ord, | |
1995 | { | |
f035d41b XL |
1996 | self.next_back() |
1997 | } | |
1a4d82fc JJ |
1998 | } |
1999 | ||
353b0b11 FG |
2000 | #[stable(feature = "default_iters", since = "1.70.0")] |
2001 | impl<K, V> Default for Range<'_, K, V> { | |
2002 | /// Creates an empty `btree_map::Range`. | |
2003 | /// | |
2004 | /// ``` | |
2005 | /// # use std::collections::btree_map; | |
2006 | /// let iter: btree_map::Range<'_, u8, u8> = Default::default(); | |
2007 | /// assert_eq!(iter.count(), 0); | |
2008 | /// ``` | |
2009 | fn default() -> Self { | |
2010 | Range { inner: Default::default() } | |
2011 | } | |
2012 | } | |
2013 | ||
a7813a04 | 2014 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
54a0048b SL |
2015 | impl<'a, K, V> Iterator for ValuesMut<'a, K, V> { |
2016 | type Item = &'a mut V; | |
2017 | ||
2018 | fn next(&mut self) -> Option<&'a mut V> { | |
2019 | self.inner.next().map(|(_, v)| v) | |
2020 | } | |
2021 | ||
2022 | fn size_hint(&self) -> (usize, Option<usize>) { | |
2023 | self.inner.size_hint() | |
2024 | } | |
416331ca XL |
2025 | |
2026 | fn last(mut self) -> Option<&'a mut V> { | |
2027 | self.next_back() | |
2028 | } | |
54a0048b SL |
2029 | } |
2030 | ||
a7813a04 | 2031 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
54a0048b SL |
2032 | impl<'a, K, V> DoubleEndedIterator for ValuesMut<'a, K, V> { |
2033 | fn next_back(&mut self) -> Option<&'a mut V> { | |
2034 | self.inner.next_back().map(|(_, v)| v) | |
2035 | } | |
2036 | } | |
2037 | ||
a7813a04 | 2038 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
9fa01778 | 2039 | impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> { |
54a0048b SL |
2040 | fn len(&self) -> usize { |
2041 | self.inner.len() | |
2042 | } | |
2043 | } | |
2044 | ||
0531ce1d | 2045 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 2046 | impl<K, V> FusedIterator for ValuesMut<'_, K, V> {} |
9e0c209e | 2047 | |
17df50a5 | 2048 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2049 | impl<K, V, A: Allocator + Clone> Iterator for IntoKeys<K, V, A> { |
3dfed10e XL |
2050 | type Item = K; |
2051 | ||
2052 | fn next(&mut self) -> Option<K> { | |
2053 | self.inner.next().map(|(k, _)| k) | |
2054 | } | |
2055 | ||
2056 | fn size_hint(&self) -> (usize, Option<usize>) { | |
2057 | self.inner.size_hint() | |
2058 | } | |
2059 | ||
2060 | fn last(mut self) -> Option<K> { | |
2061 | self.next_back() | |
2062 | } | |
2063 | ||
49aad941 FG |
2064 | fn min(mut self) -> Option<K> |
2065 | where | |
2066 | K: Ord, | |
2067 | { | |
3dfed10e XL |
2068 | self.next() |
2069 | } | |
2070 | ||
49aad941 FG |
2071 | fn max(mut self) -> Option<K> |
2072 | where | |
2073 | K: Ord, | |
2074 | { | |
3dfed10e XL |
2075 | self.next_back() |
2076 | } | |
2077 | } | |
2078 | ||
17df50a5 | 2079 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2080 | impl<K, V, A: Allocator + Clone> DoubleEndedIterator for IntoKeys<K, V, A> { |
3dfed10e XL |
2081 | fn next_back(&mut self) -> Option<K> { |
2082 | self.inner.next_back().map(|(k, _)| k) | |
2083 | } | |
2084 | } | |
2085 | ||
17df50a5 | 2086 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2087 | impl<K, V, A: Allocator + Clone> ExactSizeIterator for IntoKeys<K, V, A> { |
3dfed10e XL |
2088 | fn len(&self) -> usize { |
2089 | self.inner.len() | |
2090 | } | |
2091 | } | |
2092 | ||
17df50a5 | 2093 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2094 | impl<K, V, A: Allocator + Clone> FusedIterator for IntoKeys<K, V, A> {} |
3dfed10e | 2095 | |
353b0b11 FG |
2096 | #[stable(feature = "default_iters", since = "1.70.0")] |
2097 | impl<K, V, A> Default for IntoKeys<K, V, A> | |
2098 | where | |
2099 | A: Allocator + Default + Clone, | |
2100 | { | |
2101 | /// Creates an empty `btree_map::IntoKeys`. | |
2102 | /// | |
2103 | /// ``` | |
2104 | /// # use std::collections::btree_map; | |
2105 | /// let iter: btree_map::IntoKeys<u8, u8> = Default::default(); | |
2106 | /// assert_eq!(iter.len(), 0); | |
2107 | /// ``` | |
2108 | fn default() -> Self { | |
2109 | IntoKeys { inner: Default::default() } | |
2110 | } | |
2111 | } | |
2112 | ||
17df50a5 | 2113 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2114 | impl<K, V, A: Allocator + Clone> Iterator for IntoValues<K, V, A> { |
3dfed10e XL |
2115 | type Item = V; |
2116 | ||
2117 | fn next(&mut self) -> Option<V> { | |
2118 | self.inner.next().map(|(_, v)| v) | |
2119 | } | |
2120 | ||
2121 | fn size_hint(&self) -> (usize, Option<usize>) { | |
2122 | self.inner.size_hint() | |
2123 | } | |
2124 | ||
2125 | fn last(mut self) -> Option<V> { | |
2126 | self.next_back() | |
2127 | } | |
2128 | } | |
2129 | ||
17df50a5 | 2130 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2131 | impl<K, V, A: Allocator + Clone> DoubleEndedIterator for IntoValues<K, V, A> { |
3dfed10e XL |
2132 | fn next_back(&mut self) -> Option<V> { |
2133 | self.inner.next_back().map(|(_, v)| v) | |
2134 | } | |
2135 | } | |
2136 | ||
17df50a5 | 2137 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2138 | impl<K, V, A: Allocator + Clone> ExactSizeIterator for IntoValues<K, V, A> { |
3dfed10e XL |
2139 | fn len(&self) -> usize { |
2140 | self.inner.len() | |
2141 | } | |
2142 | } | |
2143 | ||
17df50a5 | 2144 | #[stable(feature = "map_into_keys_values", since = "1.54.0")] |
923072b8 | 2145 | impl<K, V, A: Allocator + Clone> FusedIterator for IntoValues<K, V, A> {} |
3dfed10e | 2146 | |
353b0b11 FG |
2147 | #[stable(feature = "default_iters", since = "1.70.0")] |
2148 | impl<K, V, A> Default for IntoValues<K, V, A> | |
2149 | where | |
2150 | A: Allocator + Default + Clone, | |
2151 | { | |
2152 | /// Creates an empty `btree_map::IntoValues`. | |
2153 | /// | |
2154 | /// ``` | |
2155 | /// # use std::collections::btree_map; | |
2156 | /// let iter: btree_map::IntoValues<u8, u8> = Default::default(); | |
2157 | /// assert_eq!(iter.len(), 0); | |
2158 | /// ``` | |
2159 | fn default() -> Self { | |
2160 | IntoValues { inner: Default::default() } | |
2161 | } | |
2162 | } | |
2163 | ||
cc61c64b | 2164 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 SL |
2165 | impl<'a, K, V> DoubleEndedIterator for Range<'a, K, V> { |
2166 | fn next_back(&mut self) -> Option<(&'a K, &'a V)> { | |
136023e0 | 2167 | self.inner.next_back_checked() |
1a4d82fc JJ |
2168 | } |
2169 | } | |
2170 | ||
0531ce1d | 2171 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 2172 | impl<K, V> FusedIterator for Range<'_, K, V> {} |
9e0c209e | 2173 | |
cc61c64b | 2174 | #[stable(feature = "btree_range", since = "1.17.0")] |
9fa01778 XL |
2175 | impl<K, V> Clone for Range<'_, K, V> { |
2176 | fn clone(&self) -> Self { | |
136023e0 | 2177 | Range { inner: self.inner.clone() } |
92a42be0 | 2178 | } |
1a4d82fc | 2179 | } |
1a4d82fc | 2180 | |
cc61c64b | 2181 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 | 2182 | impl<'a, K, V> Iterator for RangeMut<'a, K, V> { |
1a4d82fc JJ |
2183 | type Item = (&'a K, &'a mut V); |
2184 | ||
92a42be0 | 2185 | fn next(&mut self) -> Option<(&'a K, &'a mut V)> { |
136023e0 | 2186 | self.inner.next_checked() |
92a42be0 | 2187 | } |
416331ca XL |
2188 | |
2189 | fn last(mut self) -> Option<(&'a K, &'a mut V)> { | |
2190 | self.next_back() | |
2191 | } | |
f035d41b | 2192 | |
49aad941 FG |
2193 | fn min(mut self) -> Option<(&'a K, &'a mut V)> |
2194 | where | |
2195 | (&'a K, &'a mut V): Ord, | |
2196 | { | |
f035d41b XL |
2197 | self.next() |
2198 | } | |
2199 | ||
49aad941 FG |
2200 | fn max(mut self) -> Option<(&'a K, &'a mut V)> |
2201 | where | |
2202 | (&'a K, &'a mut V): Ord, | |
2203 | { | |
f035d41b XL |
2204 | self.next_back() |
2205 | } | |
1a4d82fc | 2206 | } |
1a4d82fc | 2207 | |
cc61c64b | 2208 | #[stable(feature = "btree_range", since = "1.17.0")] |
9cc50fc6 SL |
2209 | impl<'a, K, V> DoubleEndedIterator for RangeMut<'a, K, V> { |
2210 | fn next_back(&mut self) -> Option<(&'a K, &'a mut V)> { | |
136023e0 | 2211 | self.inner.next_back_checked() |
92a42be0 | 2212 | } |
1a4d82fc | 2213 | } |
1a4d82fc | 2214 | |
0531ce1d | 2215 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 2216 | impl<K, V> FusedIterator for RangeMut<'_, K, V> {} |
9e0c209e | 2217 | |
c30ab7b3 | 2218 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 2219 | impl<K: Ord, V> FromIterator<(K, V)> for BTreeMap<K, V> { |
3157f602 | 2220 | fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> BTreeMap<K, V> { |
c295e0f8 XL |
2221 | let mut inputs: Vec<_> = iter.into_iter().collect(); |
2222 | ||
2223 | if inputs.is_empty() { | |
2224 | return BTreeMap::new(); | |
2225 | } | |
2226 | ||
2227 | // use stable sort to preserve the insertion order. | |
2228 | inputs.sort_by(|a, b| a.0.cmp(&b.0)); | |
923072b8 | 2229 | BTreeMap::bulk_build_from_sorted_iter(inputs, Global) |
92a42be0 | 2230 | } |
1a4d82fc | 2231 | } |
1a4d82fc | 2232 | |
c30ab7b3 | 2233 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 2234 | impl<K: Ord, V, A: Allocator + Clone> Extend<(K, V)> for BTreeMap<K, V, A> { |
9cc50fc6 | 2235 | #[inline] |
3157f602 | 2236 | fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T) { |
532ac7d7 | 2237 | iter.into_iter().for_each(move |(k, v)| { |
9cc50fc6 | 2238 | self.insert(k, v); |
532ac7d7 | 2239 | }); |
92a42be0 | 2240 | } |
f9f354fc XL |
2241 | |
2242 | #[inline] | |
2243 | fn extend_one(&mut self, (k, v): (K, V)) { | |
2244 | self.insert(k, v); | |
2245 | } | |
c34b1796 | 2246 | } |
85aaf69f | 2247 | |
c30ab7b3 | 2248 | #[stable(feature = "extend_ref", since = "1.2.0")] |
923072b8 FG |
2249 | impl<'a, K: Ord + Copy, V: Copy, A: Allocator + Clone> Extend<(&'a K, &'a V)> |
2250 | for BTreeMap<K, V, A> | |
2251 | { | |
3157f602 | 2252 | fn extend<I: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iter: I) { |
9cc50fc6 | 2253 | self.extend(iter.into_iter().map(|(&key, &value)| (key, value))); |
92a42be0 | 2254 | } |
f9f354fc XL |
2255 | |
2256 | #[inline] | |
2257 | fn extend_one(&mut self, (&k, &v): (&'a K, &'a V)) { | |
2258 | self.insert(k, v); | |
2259 | } | |
85aaf69f | 2260 | } |
9cc50fc6 | 2261 | |
c30ab7b3 | 2262 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 2263 | impl<K: Hash, V: Hash, A: Allocator + Clone> Hash for BTreeMap<K, V, A> { |
9cc50fc6 | 2264 | fn hash<H: Hasher>(&self, state: &mut H) { |
04454e1e | 2265 | state.write_length_prefix(self.len()); |
9cc50fc6 SL |
2266 | for elt in self { |
2267 | elt.hash(state); | |
2268 | } | |
92a42be0 | 2269 | } |
85aaf69f SL |
2270 | } |
2271 | ||
c30ab7b3 | 2272 | #[stable(feature = "rust1", since = "1.0.0")] |
94222f64 | 2273 | impl<K, V> Default for BTreeMap<K, V> { |
fc512014 | 2274 | /// Creates an empty `BTreeMap`. |
9cc50fc6 SL |
2275 | fn default() -> BTreeMap<K, V> { |
2276 | BTreeMap::new() | |
92a42be0 | 2277 | } |
85aaf69f | 2278 | } |
9cc50fc6 | 2279 | |
c30ab7b3 | 2280 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 FG |
2281 | impl<K: PartialEq, V: PartialEq, A: Allocator + Clone> PartialEq for BTreeMap<K, V, A> { |
2282 | fn eq(&self, other: &BTreeMap<K, V, A>) -> bool { | |
3157f602 | 2283 | self.len() == other.len() && self.iter().zip(other).all(|(a, b)| a == b) |
92a42be0 | 2284 | } |
85aaf69f SL |
2285 | } |
2286 | ||
c30ab7b3 | 2287 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 2288 | impl<K: Eq, V: Eq, A: Allocator + Clone> Eq for BTreeMap<K, V, A> {} |
c34b1796 | 2289 | |
c30ab7b3 | 2290 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 2291 | impl<K: PartialOrd, V: PartialOrd, A: Allocator + Clone> PartialOrd for BTreeMap<K, V, A> { |
9cc50fc6 | 2292 | #[inline] |
923072b8 | 2293 | fn partial_cmp(&self, other: &BTreeMap<K, V, A>) -> Option<Ordering> { |
9cc50fc6 | 2294 | self.iter().partial_cmp(other.iter()) |
c34b1796 | 2295 | } |
1a4d82fc JJ |
2296 | } |
2297 | ||
c30ab7b3 | 2298 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 2299 | impl<K: Ord, V: Ord, A: Allocator + Clone> Ord for BTreeMap<K, V, A> { |
9cc50fc6 | 2300 | #[inline] |
923072b8 | 2301 | fn cmp(&self, other: &BTreeMap<K, V, A>) -> Ordering { |
9cc50fc6 | 2302 | self.iter().cmp(other.iter()) |
1a4d82fc JJ |
2303 | } |
2304 | } | |
2305 | ||
c30ab7b3 | 2306 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 2307 | impl<K: Debug, V: Debug, A: Allocator + Clone> Debug for BTreeMap<K, V, A> { |
9fa01778 | 2308 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
9cc50fc6 | 2309 | f.debug_map().entries(self.iter()).finish() |
1a4d82fc | 2310 | } |
9cc50fc6 | 2311 | } |
1a4d82fc | 2312 | |
c30ab7b3 | 2313 | #[stable(feature = "rust1", since = "1.0.0")] |
923072b8 | 2314 | impl<K, Q: ?Sized, V, A: Allocator + Clone> Index<&Q> for BTreeMap<K, V, A> |
dfeec247 | 2315 | where |
5869c6ff | 2316 | K: Borrow<Q> + Ord, |
dfeec247 | 2317 | Q: Ord, |
9cc50fc6 SL |
2318 | { |
2319 | type Output = V; | |
1a4d82fc | 2320 | |
2c00a5a8 XL |
2321 | /// Returns a reference to the value corresponding to the supplied key. |
2322 | /// | |
2323 | /// # Panics | |
2324 | /// | |
2325 | /// Panics if the key is not present in the `BTreeMap`. | |
9cc50fc6 SL |
2326 | #[inline] |
2327 | fn index(&self, key: &Q) -> &V { | |
2328 | self.get(key).expect("no entry found for key") | |
1a4d82fc | 2329 | } |
9cc50fc6 | 2330 | } |
1a4d82fc | 2331 | |
94222f64 XL |
2332 | #[stable(feature = "std_collections_from_array", since = "1.56.0")] |
2333 | impl<K: Ord, V, const N: usize> From<[(K, V); N]> for BTreeMap<K, V> { | |
5099ac24 FG |
2334 | /// Converts a `[(K, V); N]` into a `BTreeMap<(K, V)>`. |
2335 | /// | |
94222f64 XL |
2336 | /// ``` |
2337 | /// use std::collections::BTreeMap; | |
2338 | /// | |
2339 | /// let map1 = BTreeMap::from([(1, 2), (3, 4)]); | |
2340 | /// let map2: BTreeMap<_, _> = [(1, 2), (3, 4)].into(); | |
2341 | /// assert_eq!(map1, map2); | |
2342 | /// ``` | |
c295e0f8 XL |
2343 | fn from(mut arr: [(K, V); N]) -> Self { |
2344 | if N == 0 { | |
2345 | return BTreeMap::new(); | |
2346 | } | |
2347 | ||
2348 | // use stable sort to preserve the insertion order. | |
2349 | arr.sort_by(|a, b| a.0.cmp(&b.0)); | |
923072b8 | 2350 | BTreeMap::bulk_build_from_sorted_iter(arr, Global) |
94222f64 XL |
2351 | } |
2352 | } | |
2353 | ||
923072b8 | 2354 | impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> { |
7453a54e | 2355 | /// Gets an iterator over the entries of the map, sorted by key. |
1a4d82fc | 2356 | /// |
c34b1796 | 2357 | /// # Examples |
1a4d82fc JJ |
2358 | /// |
2359 | /// ``` | |
2360 | /// use std::collections::BTreeMap; | |
2361 | /// | |
2362 | /// let mut map = BTreeMap::new(); | |
85aaf69f | 2363 | /// map.insert(3, "c"); |
7453a54e SL |
2364 | /// map.insert(2, "b"); |
2365 | /// map.insert(1, "a"); | |
1a4d82fc JJ |
2366 | /// |
2367 | /// for (key, value) in map.iter() { | |
5e7ed085 | 2368 | /// println!("{key}: {value}"); |
1a4d82fc JJ |
2369 | /// } |
2370 | /// | |
2371 | /// let (first_key, first_value) = map.iter().next().unwrap(); | |
85aaf69f | 2372 | /// assert_eq!((*first_key, *first_value), (1, "a")); |
1a4d82fc | 2373 | /// ``` |
85aaf69f | 2374 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 2375 | pub fn iter(&self) -> Iter<'_, K, V> { |
f9f354fc | 2376 | if let Some(root) = &self.root { |
6a06907d | 2377 | let full_range = root.reborrow().full_range(); |
f9f354fc | 2378 | |
94222f64 | 2379 | Iter { range: full_range, length: self.length } |
f9f354fc | 2380 | } else { |
94222f64 | 2381 | Iter { range: LazyLeafRange::none(), length: 0 } |
1a4d82fc JJ |
2382 | } |
2383 | } | |
2384 | ||
7453a54e | 2385 | /// Gets a mutable iterator over the entries of the map, sorted by key. |
1a4d82fc JJ |
2386 | /// |
2387 | /// # Examples | |
2388 | /// | |
2389 | /// ``` | |
2390 | /// use std::collections::BTreeMap; | |
2391 | /// | |
a2a8927a XL |
2392 | /// let mut map = BTreeMap::from([ |
2393 | /// ("a", 1), | |
2394 | /// ("b", 2), | |
2395 | /// ("c", 3), | |
2396 | /// ]); | |
1a4d82fc JJ |
2397 | /// |
2398 | /// // add 10 to the value if the key isn't "a" | |
2399 | /// for (key, value) in map.iter_mut() { | |
2400 | /// if key != &"a" { | |
2401 | /// *value += 10; | |
2402 | /// } | |
2403 | /// } | |
2404 | /// ``` | |
85aaf69f | 2405 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 2406 | pub fn iter_mut(&mut self) -> IterMut<'_, K, V> { |
f9f354fc | 2407 | if let Some(root) = &mut self.root { |
6a06907d | 2408 | let full_range = root.borrow_valmut().full_range(); |
f9f354fc | 2409 | |
94222f64 | 2410 | IterMut { range: full_range, length: self.length, _marker: PhantomData } |
f9f354fc | 2411 | } else { |
94222f64 | 2412 | IterMut { range: LazyLeafRange::none(), length: 0, _marker: PhantomData } |
1a4d82fc JJ |
2413 | } |
2414 | } | |
2415 | ||
7453a54e | 2416 | /// Gets an iterator over the keys of the map, in sorted order. |
1a4d82fc JJ |
2417 | /// |
2418 | /// # Examples | |
2419 | /// | |
2420 | /// ``` | |
2421 | /// use std::collections::BTreeMap; | |
2422 | /// | |
2423 | /// let mut a = BTreeMap::new(); | |
85aaf69f | 2424 | /// a.insert(2, "b"); |
7453a54e | 2425 | /// a.insert(1, "a"); |
1a4d82fc | 2426 | /// |
62682a34 | 2427 | /// let keys: Vec<_> = a.keys().cloned().collect(); |
c34b1796 | 2428 | /// assert_eq!(keys, [1, 2]); |
1a4d82fc | 2429 | /// ``` |
85aaf69f | 2430 | #[stable(feature = "rust1", since = "1.0.0")] |
416331ca | 2431 | pub fn keys(&self) -> Keys<'_, K, V> { |
9cc50fc6 | 2432 | Keys { inner: self.iter() } |
1a4d82fc JJ |
2433 | } |
2434 | ||
7453a54e | 2435 | /// Gets an iterator over the values of the map, in order by key. |
1a4d82fc JJ |
2436 | /// |
2437 | /// # Examples | |
2438 | /// | |
2439 | /// ``` | |
2440 | /// use std::collections::BTreeMap; | |
2441 | /// | |
2442 | /// let mut a = BTreeMap::new(); | |
7453a54e SL |
2443 | /// a.insert(1, "hello"); |
2444 | /// a.insert(2, "goodbye"); | |
1a4d82fc JJ |
2445 | /// |
2446 | /// let values: Vec<&str> = a.values().cloned().collect(); | |
7453a54e | 2447 | /// assert_eq!(values, ["hello", "goodbye"]); |
1a4d82fc | 2448 | /// ``` |
85aaf69f | 2449 | #[stable(feature = "rust1", since = "1.0.0")] |
416331ca | 2450 | pub fn values(&self) -> Values<'_, K, V> { |
9cc50fc6 | 2451 | Values { inner: self.iter() } |
1a4d82fc JJ |
2452 | } |
2453 | ||
54a0048b SL |
2454 | /// Gets a mutable iterator over the values of the map, in order by key. |
2455 | /// | |
2456 | /// # Examples | |
2457 | /// | |
54a0048b | 2458 | /// ``` |
54a0048b SL |
2459 | /// use std::collections::BTreeMap; |
2460 | /// | |
2461 | /// let mut a = BTreeMap::new(); | |
2462 | /// a.insert(1, String::from("hello")); | |
2463 | /// a.insert(2, String::from("goodbye")); | |
2464 | /// | |
2465 | /// for value in a.values_mut() { | |
2466 | /// value.push_str("!"); | |
2467 | /// } | |
2468 | /// | |
2469 | /// let values: Vec<String> = a.values().cloned().collect(); | |
2470 | /// assert_eq!(values, [String::from("hello!"), | |
2471 | /// String::from("goodbye!")]); | |
2472 | /// ``` | |
a7813a04 | 2473 | #[stable(feature = "map_values_mut", since = "1.10.0")] |
9fa01778 | 2474 | pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> { |
54a0048b SL |
2475 | ValuesMut { inner: self.iter_mut() } |
2476 | } | |
2477 | ||
9346a6ac | 2478 | /// Returns the number of elements in the map. |
1a4d82fc JJ |
2479 | /// |
2480 | /// # Examples | |
2481 | /// | |
2482 | /// ``` | |
2483 | /// use std::collections::BTreeMap; | |
2484 | /// | |
2485 | /// let mut a = BTreeMap::new(); | |
2486 | /// assert_eq!(a.len(), 0); | |
85aaf69f | 2487 | /// a.insert(1, "a"); |
1a4d82fc JJ |
2488 | /// assert_eq!(a.len(), 1); |
2489 | /// ``` | |
3c0e092e | 2490 | #[must_use] |
85aaf69f | 2491 | #[stable(feature = "rust1", since = "1.0.0")] |
2b03887a FG |
2492 | #[rustc_const_unstable( |
2493 | feature = "const_btree_len", | |
2494 | issue = "71835", | |
2495 | implied_by = "const_btree_new" | |
2496 | )] | |
29967ef6 | 2497 | pub const fn len(&self) -> usize { |
92a42be0 SL |
2498 | self.length |
2499 | } | |
1a4d82fc | 2500 | |
cc61c64b | 2501 | /// Returns `true` if the map contains no elements. |
1a4d82fc JJ |
2502 | /// |
2503 | /// # Examples | |
2504 | /// | |
2505 | /// ``` | |
2506 | /// use std::collections::BTreeMap; | |
2507 | /// | |
2508 | /// let mut a = BTreeMap::new(); | |
2509 | /// assert!(a.is_empty()); | |
85aaf69f | 2510 | /// a.insert(1, "a"); |
1a4d82fc JJ |
2511 | /// assert!(!a.is_empty()); |
2512 | /// ``` | |
3c0e092e | 2513 | #[must_use] |
85aaf69f | 2514 | #[stable(feature = "rust1", since = "1.0.0")] |
2b03887a FG |
2515 | #[rustc_const_unstable( |
2516 | feature = "const_btree_len", | |
2517 | issue = "71835", | |
2518 | implied_by = "const_btree_new" | |
2519 | )] | |
29967ef6 | 2520 | pub const fn is_empty(&self) -> bool { |
92a42be0 SL |
2521 | self.len() == 0 |
2522 | } | |
9ffffee4 FG |
2523 | |
2524 | /// Returns a [`Cursor`] pointing at the first element that is above the | |
2525 | /// given bound. | |
2526 | /// | |
2527 | /// If no such element exists then a cursor pointing at the "ghost" | |
2528 | /// non-element is returned. | |
2529 | /// | |
2530 | /// Passing [`Bound::Unbounded`] will return a cursor pointing at the first | |
2531 | /// element of the map. | |
2532 | /// | |
2533 | /// # Examples | |
2534 | /// | |
9ffffee4 FG |
2535 | /// ``` |
2536 | /// #![feature(btree_cursors)] | |
2537 | /// | |
2538 | /// use std::collections::BTreeMap; | |
2539 | /// use std::ops::Bound; | |
2540 | /// | |
2541 | /// let mut a = BTreeMap::new(); | |
2542 | /// a.insert(1, "a"); | |
2543 | /// a.insert(2, "b"); | |
2544 | /// a.insert(3, "c"); | |
2545 | /// a.insert(4, "c"); | |
add651ee FG |
2546 | /// let cursor = a.lower_bound(Bound::Included(&2)); |
2547 | /// assert_eq!(cursor.key(), Some(&2)); | |
9ffffee4 FG |
2548 | /// let cursor = a.lower_bound(Bound::Excluded(&2)); |
2549 | /// assert_eq!(cursor.key(), Some(&3)); | |
2550 | /// ``` | |
2551 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2552 | pub fn lower_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> | |
2553 | where | |
2554 | K: Borrow<Q> + Ord, | |
2555 | Q: Ord, | |
2556 | { | |
2557 | let root_node = match self.root.as_ref() { | |
2558 | None => return Cursor { current: None, root: None }, | |
2559 | Some(root) => root.reborrow(), | |
2560 | }; | |
2561 | let edge = root_node.lower_bound(SearchBound::from_range(bound)); | |
2562 | Cursor { current: edge.next_kv().ok(), root: self.root.as_ref() } | |
2563 | } | |
2564 | ||
2565 | /// Returns a [`CursorMut`] pointing at the first element that is above the | |
2566 | /// given bound. | |
2567 | /// | |
2568 | /// If no such element exists then a cursor pointing at the "ghost" | |
2569 | /// non-element is returned. | |
2570 | /// | |
2571 | /// Passing [`Bound::Unbounded`] will return a cursor pointing at the first | |
2572 | /// element of the map. | |
2573 | /// | |
2574 | /// # Examples | |
2575 | /// | |
9ffffee4 FG |
2576 | /// ``` |
2577 | /// #![feature(btree_cursors)] | |
2578 | /// | |
2579 | /// use std::collections::BTreeMap; | |
2580 | /// use std::ops::Bound; | |
2581 | /// | |
2582 | /// let mut a = BTreeMap::new(); | |
2583 | /// a.insert(1, "a"); | |
2584 | /// a.insert(2, "b"); | |
2585 | /// a.insert(3, "c"); | |
2586 | /// a.insert(4, "c"); | |
add651ee FG |
2587 | /// let cursor = a.lower_bound_mut(Bound::Included(&2)); |
2588 | /// assert_eq!(cursor.key(), Some(&2)); | |
9ffffee4 FG |
2589 | /// let cursor = a.lower_bound_mut(Bound::Excluded(&2)); |
2590 | /// assert_eq!(cursor.key(), Some(&3)); | |
2591 | /// ``` | |
2592 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2593 | pub fn lower_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A> | |
2594 | where | |
2595 | K: Borrow<Q> + Ord, | |
2596 | Q: Ord, | |
2597 | { | |
2598 | let (root, dormant_root) = DormantMutRef::new(&mut self.root); | |
2599 | let root_node = match root.as_mut() { | |
2600 | None => { | |
2601 | return CursorMut { | |
2602 | current: None, | |
2603 | root: dormant_root, | |
2604 | length: &mut self.length, | |
2605 | alloc: &mut *self.alloc, | |
2606 | }; | |
2607 | } | |
2608 | Some(root) => root.borrow_mut(), | |
2609 | }; | |
2610 | let edge = root_node.lower_bound(SearchBound::from_range(bound)); | |
2611 | CursorMut { | |
2612 | current: edge.next_kv().ok(), | |
2613 | root: dormant_root, | |
2614 | length: &mut self.length, | |
2615 | alloc: &mut *self.alloc, | |
2616 | } | |
2617 | } | |
2618 | ||
2619 | /// Returns a [`Cursor`] pointing at the last element that is below the | |
2620 | /// given bound. | |
2621 | /// | |
2622 | /// If no such element exists then a cursor pointing at the "ghost" | |
2623 | /// non-element is returned. | |
2624 | /// | |
2625 | /// Passing [`Bound::Unbounded`] will return a cursor pointing at the last | |
2626 | /// element of the map. | |
2627 | /// | |
2628 | /// # Examples | |
2629 | /// | |
9ffffee4 FG |
2630 | /// ``` |
2631 | /// #![feature(btree_cursors)] | |
2632 | /// | |
2633 | /// use std::collections::BTreeMap; | |
2634 | /// use std::ops::Bound; | |
2635 | /// | |
2636 | /// let mut a = BTreeMap::new(); | |
2637 | /// a.insert(1, "a"); | |
2638 | /// a.insert(2, "b"); | |
2639 | /// a.insert(3, "c"); | |
2640 | /// a.insert(4, "c"); | |
add651ee FG |
2641 | /// let cursor = a.upper_bound(Bound::Included(&3)); |
2642 | /// assert_eq!(cursor.key(), Some(&3)); | |
9ffffee4 FG |
2643 | /// let cursor = a.upper_bound(Bound::Excluded(&3)); |
2644 | /// assert_eq!(cursor.key(), Some(&2)); | |
2645 | /// ``` | |
2646 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2647 | pub fn upper_bound<Q>(&self, bound: Bound<&Q>) -> Cursor<'_, K, V> | |
2648 | where | |
2649 | K: Borrow<Q> + Ord, | |
2650 | Q: Ord, | |
2651 | { | |
2652 | let root_node = match self.root.as_ref() { | |
2653 | None => return Cursor { current: None, root: None }, | |
2654 | Some(root) => root.reborrow(), | |
2655 | }; | |
2656 | let edge = root_node.upper_bound(SearchBound::from_range(bound)); | |
2657 | Cursor { current: edge.next_back_kv().ok(), root: self.root.as_ref() } | |
2658 | } | |
2659 | ||
2660 | /// Returns a [`CursorMut`] pointing at the last element that is below the | |
2661 | /// given bound. | |
2662 | /// | |
2663 | /// If no such element exists then a cursor pointing at the "ghost" | |
2664 | /// non-element is returned. | |
2665 | /// | |
2666 | /// Passing [`Bound::Unbounded`] will return a cursor pointing at the last | |
2667 | /// element of the map. | |
2668 | /// | |
2669 | /// # Examples | |
2670 | /// | |
9ffffee4 FG |
2671 | /// ``` |
2672 | /// #![feature(btree_cursors)] | |
2673 | /// | |
2674 | /// use std::collections::BTreeMap; | |
2675 | /// use std::ops::Bound; | |
2676 | /// | |
2677 | /// let mut a = BTreeMap::new(); | |
2678 | /// a.insert(1, "a"); | |
2679 | /// a.insert(2, "b"); | |
2680 | /// a.insert(3, "c"); | |
2681 | /// a.insert(4, "c"); | |
add651ee FG |
2682 | /// let cursor = a.upper_bound_mut(Bound::Included(&3)); |
2683 | /// assert_eq!(cursor.key(), Some(&3)); | |
9ffffee4 FG |
2684 | /// let cursor = a.upper_bound_mut(Bound::Excluded(&3)); |
2685 | /// assert_eq!(cursor.key(), Some(&2)); | |
2686 | /// ``` | |
2687 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2688 | pub fn upper_bound_mut<Q>(&mut self, bound: Bound<&Q>) -> CursorMut<'_, K, V, A> | |
2689 | where | |
2690 | K: Borrow<Q> + Ord, | |
2691 | Q: Ord, | |
2692 | { | |
2693 | let (root, dormant_root) = DormantMutRef::new(&mut self.root); | |
2694 | let root_node = match root.as_mut() { | |
2695 | None => { | |
2696 | return CursorMut { | |
2697 | current: None, | |
2698 | root: dormant_root, | |
2699 | length: &mut self.length, | |
2700 | alloc: &mut *self.alloc, | |
2701 | }; | |
2702 | } | |
2703 | Some(root) => root.borrow_mut(), | |
2704 | }; | |
2705 | let edge = root_node.upper_bound(SearchBound::from_range(bound)); | |
2706 | CursorMut { | |
2707 | current: edge.next_back_kv().ok(), | |
2708 | root: dormant_root, | |
2709 | length: &mut self.length, | |
2710 | alloc: &mut *self.alloc, | |
2711 | } | |
2712 | } | |
2713 | } | |
2714 | ||
2715 | /// A cursor over a `BTreeMap`. | |
2716 | /// | |
2717 | /// A `Cursor` is like an iterator, except that it can freely seek back-and-forth. | |
2718 | /// | |
2719 | /// Cursors always point to an element in the tree, and index in a logically circular way. | |
2720 | /// To accommodate this, there is a "ghost" non-element that yields `None` between the last and | |
2721 | /// first elements of the tree. | |
2722 | /// | |
2723 | /// A `Cursor` is created with the [`BTreeMap::lower_bound`] and [`BTreeMap::upper_bound`] methods. | |
2724 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2725 | pub struct Cursor<'a, K: 'a, V: 'a> { | |
2726 | current: Option<Handle<NodeRef<marker::Immut<'a>, K, V, marker::LeafOrInternal>, marker::KV>>, | |
2727 | root: Option<&'a node::Root<K, V>>, | |
2728 | } | |
2729 | ||
2730 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2731 | impl<K, V> Clone for Cursor<'_, K, V> { | |
2732 | fn clone(&self) -> Self { | |
2733 | let Cursor { current, root } = *self; | |
2734 | Cursor { current, root } | |
2735 | } | |
2736 | } | |
2737 | ||
2738 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2739 | impl<K: Debug, V: Debug> Debug for Cursor<'_, K, V> { | |
2740 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
2741 | f.debug_tuple("Cursor").field(&self.key_value()).finish() | |
2742 | } | |
2743 | } | |
2744 | ||
2745 | /// A cursor over a `BTreeMap` with editing operations. | |
2746 | /// | |
2747 | /// A `Cursor` is like an iterator, except that it can freely seek back-and-forth, and can | |
2748 | /// safely mutate the tree during iteration. This is because the lifetime of its yielded | |
2749 | /// references is tied to its own lifetime, instead of just the underlying tree. This means | |
2750 | /// cursors cannot yield multiple elements at once. | |
2751 | /// | |
2752 | /// Cursors always point to an element in the tree, and index in a logically circular way. | |
2753 | /// To accommodate this, there is a "ghost" non-element that yields `None` between the last and | |
2754 | /// first elements of the tree. | |
2755 | /// | |
2756 | /// A `Cursor` is created with the [`BTreeMap::lower_bound_mut`] and [`BTreeMap::upper_bound_mut`] | |
2757 | /// methods. | |
2758 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2759 | pub struct CursorMut< | |
2760 | 'a, | |
2761 | K: 'a, | |
2762 | V: 'a, | |
2763 | #[unstable(feature = "allocator_api", issue = "32838")] A = Global, | |
2764 | > { | |
2765 | current: Option<Handle<NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>, marker::KV>>, | |
2766 | root: DormantMutRef<'a, Option<node::Root<K, V>>>, | |
2767 | length: &'a mut usize, | |
2768 | alloc: &'a mut A, | |
2769 | } | |
2770 | ||
2771 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2772 | impl<K: Debug, V: Debug, A> Debug for CursorMut<'_, K, V, A> { | |
2773 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
2774 | f.debug_tuple("CursorMut").field(&self.key_value()).finish() | |
2775 | } | |
2776 | } | |
2777 | ||
2778 | impl<'a, K, V> Cursor<'a, K, V> { | |
2779 | /// Moves the cursor to the next element of the `BTreeMap`. | |
2780 | /// | |
2781 | /// If the cursor is pointing to the "ghost" non-element then this will move it to | |
2782 | /// the first element of the `BTreeMap`. If it is pointing to the last | |
2783 | /// element of the `BTreeMap` then this will move it to the "ghost" non-element. | |
2784 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2785 | pub fn move_next(&mut self) { | |
2786 | match self.current.take() { | |
2787 | None => { | |
2788 | self.current = self.root.and_then(|root| { | |
2789 | root.reborrow().first_leaf_edge().forget_node_type().right_kv().ok() | |
2790 | }); | |
2791 | } | |
2792 | Some(current) => { | |
2793 | self.current = current.next_leaf_edge().next_kv().ok(); | |
2794 | } | |
2795 | } | |
2796 | } | |
2797 | ||
2798 | /// Moves the cursor to the previous element of the `BTreeMap`. | |
2799 | /// | |
2800 | /// If the cursor is pointing to the "ghost" non-element then this will move it to | |
2801 | /// the last element of the `BTreeMap`. If it is pointing to the first | |
2802 | /// element of the `BTreeMap` then this will move it to the "ghost" non-element. | |
2803 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2804 | pub fn move_prev(&mut self) { | |
2805 | match self.current.take() { | |
2806 | None => { | |
2807 | self.current = self.root.and_then(|root| { | |
2808 | root.reborrow().last_leaf_edge().forget_node_type().left_kv().ok() | |
2809 | }); | |
2810 | } | |
2811 | Some(current) => { | |
2812 | self.current = current.next_back_leaf_edge().next_back_kv().ok(); | |
2813 | } | |
2814 | } | |
2815 | } | |
2816 | ||
2817 | /// Returns a reference to the key of the element that the cursor is | |
2818 | /// currently pointing to. | |
2819 | /// | |
2820 | /// This returns `None` if the cursor is currently pointing to the | |
2821 | /// "ghost" non-element. | |
2822 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2823 | pub fn key(&self) -> Option<&'a K> { | |
2824 | self.current.as_ref().map(|current| current.into_kv().0) | |
2825 | } | |
2826 | ||
2827 | /// Returns a reference to the value of the element that the cursor is | |
2828 | /// currently pointing to. | |
2829 | /// | |
2830 | /// This returns `None` if the cursor is currently pointing to the | |
2831 | /// "ghost" non-element. | |
2832 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2833 | pub fn value(&self) -> Option<&'a V> { | |
2834 | self.current.as_ref().map(|current| current.into_kv().1) | |
2835 | } | |
2836 | ||
2837 | /// Returns a reference to the key and value of the element that the cursor | |
2838 | /// is currently pointing to. | |
2839 | /// | |
2840 | /// This returns `None` if the cursor is currently pointing to the | |
2841 | /// "ghost" non-element. | |
2842 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2843 | pub fn key_value(&self) -> Option<(&'a K, &'a V)> { | |
2844 | self.current.as_ref().map(|current| current.into_kv()) | |
2845 | } | |
2846 | ||
2847 | /// Returns a reference to the next element. | |
2848 | /// | |
2849 | /// If the cursor is pointing to the "ghost" non-element then this returns | |
2850 | /// the first element of the `BTreeMap`. If it is pointing to the last | |
2851 | /// element of the `BTreeMap` then this returns `None`. | |
2852 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2853 | pub fn peek_next(&self) -> Option<(&'a K, &'a V)> { | |
2854 | let mut next = self.clone(); | |
2855 | next.move_next(); | |
2856 | next.current.as_ref().map(|current| current.into_kv()) | |
2857 | } | |
2858 | ||
2859 | /// Returns a reference to the previous element. | |
2860 | /// | |
2861 | /// If the cursor is pointing to the "ghost" non-element then this returns | |
2862 | /// the last element of the `BTreeMap`. If it is pointing to the first | |
2863 | /// element of the `BTreeMap` then this returns `None`. | |
2864 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2865 | pub fn peek_prev(&self) -> Option<(&'a K, &'a V)> { | |
2866 | let mut prev = self.clone(); | |
2867 | prev.move_prev(); | |
2868 | prev.current.as_ref().map(|current| current.into_kv()) | |
2869 | } | |
2870 | } | |
2871 | ||
2872 | impl<'a, K, V, A> CursorMut<'a, K, V, A> { | |
2873 | /// Moves the cursor to the next element of the `BTreeMap`. | |
2874 | /// | |
2875 | /// If the cursor is pointing to the "ghost" non-element then this will move it to | |
2876 | /// the first element of the `BTreeMap`. If it is pointing to the last | |
2877 | /// element of the `BTreeMap` then this will move it to the "ghost" non-element. | |
2878 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2879 | pub fn move_next(&mut self) { | |
2880 | match self.current.take() { | |
2881 | None => { | |
2882 | // SAFETY: The previous borrow of root has ended. | |
2883 | self.current = unsafe { self.root.reborrow() }.as_mut().and_then(|root| { | |
2884 | root.borrow_mut().first_leaf_edge().forget_node_type().right_kv().ok() | |
2885 | }); | |
2886 | } | |
2887 | Some(current) => { | |
2888 | self.current = current.next_leaf_edge().next_kv().ok(); | |
2889 | } | |
2890 | } | |
2891 | } | |
2892 | ||
2893 | /// Moves the cursor to the previous element of the `BTreeMap`. | |
2894 | /// | |
2895 | /// If the cursor is pointing to the "ghost" non-element then this will move it to | |
2896 | /// the last element of the `BTreeMap`. If it is pointing to the first | |
2897 | /// element of the `BTreeMap` then this will move it to the "ghost" non-element. | |
2898 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2899 | pub fn move_prev(&mut self) { | |
2900 | match self.current.take() { | |
2901 | None => { | |
2902 | // SAFETY: The previous borrow of root has ended. | |
2903 | self.current = unsafe { self.root.reborrow() }.as_mut().and_then(|root| { | |
2904 | root.borrow_mut().last_leaf_edge().forget_node_type().left_kv().ok() | |
2905 | }); | |
2906 | } | |
2907 | Some(current) => { | |
2908 | self.current = current.next_back_leaf_edge().next_back_kv().ok(); | |
2909 | } | |
2910 | } | |
2911 | } | |
2912 | ||
2913 | /// Returns a reference to the key of the element that the cursor is | |
2914 | /// currently pointing to. | |
2915 | /// | |
2916 | /// This returns `None` if the cursor is currently pointing to the | |
2917 | /// "ghost" non-element. | |
2918 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2919 | pub fn key(&self) -> Option<&K> { | |
2920 | self.current.as_ref().map(|current| current.reborrow().into_kv().0) | |
2921 | } | |
2922 | ||
2923 | /// Returns a reference to the value of the element that the cursor is | |
2924 | /// currently pointing to. | |
2925 | /// | |
2926 | /// This returns `None` if the cursor is currently pointing to the | |
2927 | /// "ghost" non-element. | |
2928 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2929 | pub fn value(&self) -> Option<&V> { | |
2930 | self.current.as_ref().map(|current| current.reborrow().into_kv().1) | |
2931 | } | |
2932 | ||
2933 | /// Returns a reference to the key and value of the element that the cursor | |
2934 | /// is currently pointing to. | |
2935 | /// | |
2936 | /// This returns `None` if the cursor is currently pointing to the | |
2937 | /// "ghost" non-element. | |
2938 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2939 | pub fn key_value(&self) -> Option<(&K, &V)> { | |
2940 | self.current.as_ref().map(|current| current.reborrow().into_kv()) | |
2941 | } | |
2942 | ||
2943 | /// Returns a mutable reference to the value of the element that the cursor | |
2944 | /// is currently pointing to. | |
2945 | /// | |
2946 | /// This returns `None` if the cursor is currently pointing to the | |
2947 | /// "ghost" non-element. | |
2948 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2949 | pub fn value_mut(&mut self) -> Option<&mut V> { | |
2950 | self.current.as_mut().map(|current| current.kv_mut().1) | |
2951 | } | |
2952 | ||
2953 | /// Returns a reference to the key and mutable reference to the value of the | |
2954 | /// element that the cursor is currently pointing to. | |
2955 | /// | |
2956 | /// This returns `None` if the cursor is currently pointing to the | |
2957 | /// "ghost" non-element. | |
2958 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2959 | pub fn key_value_mut(&mut self) -> Option<(&K, &mut V)> { | |
2960 | self.current.as_mut().map(|current| { | |
2961 | let (k, v) = current.kv_mut(); | |
2962 | (&*k, v) | |
2963 | }) | |
2964 | } | |
2965 | ||
49aad941 | 2966 | /// Returns a mutable reference to the key of the element that the cursor is |
9ffffee4 FG |
2967 | /// currently pointing to. |
2968 | /// | |
2969 | /// This returns `None` if the cursor is currently pointing to the | |
2970 | /// "ghost" non-element. | |
2971 | /// | |
2972 | /// # Safety | |
2973 | /// | |
2974 | /// This can be used to modify the key, but you must ensure that the | |
2975 | /// `BTreeMap` invariants are maintained. Specifically: | |
2976 | /// | |
2977 | /// * The key must remain unique within the tree. | |
2978 | /// * The key must remain in sorted order with regards to other elements in | |
2979 | /// the tree. | |
2980 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2981 | pub unsafe fn key_mut_unchecked(&mut self) -> Option<&mut K> { | |
2982 | self.current.as_mut().map(|current| current.kv_mut().0) | |
2983 | } | |
2984 | ||
2985 | /// Returns a reference to the key and value of the next element. | |
2986 | /// | |
2987 | /// If the cursor is pointing to the "ghost" non-element then this returns | |
2988 | /// the first element of the `BTreeMap`. If it is pointing to the last | |
2989 | /// element of the `BTreeMap` then this returns `None`. | |
2990 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
2991 | pub fn peek_next(&mut self) -> Option<(&K, &mut V)> { | |
2992 | let (k, v) = match self.current { | |
2993 | None => { | |
2994 | // SAFETY: The previous borrow of root has ended. | |
2995 | unsafe { self.root.reborrow() } | |
2996 | .as_mut()? | |
2997 | .borrow_mut() | |
2998 | .first_leaf_edge() | |
2999 | .next_kv() | |
3000 | .ok()? | |
3001 | .into_kv_valmut() | |
3002 | } | |
3003 | // SAFETY: We're not using this to mutate the tree. | |
3004 | Some(ref mut current) => { | |
3005 | unsafe { current.reborrow_mut() }.next_leaf_edge().next_kv().ok()?.into_kv_valmut() | |
3006 | } | |
3007 | }; | |
3008 | Some((k, v)) | |
3009 | } | |
3010 | ||
3011 | /// Returns a reference to the key and value of the previous element. | |
3012 | /// | |
3013 | /// If the cursor is pointing to the "ghost" non-element then this returns | |
3014 | /// the last element of the `BTreeMap`. If it is pointing to the first | |
3015 | /// element of the `BTreeMap` then this returns `None`. | |
3016 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3017 | pub fn peek_prev(&mut self) -> Option<(&K, &mut V)> { | |
3018 | let (k, v) = match self.current.as_mut() { | |
3019 | None => { | |
3020 | // SAFETY: The previous borrow of root has ended. | |
3021 | unsafe { self.root.reborrow() } | |
3022 | .as_mut()? | |
3023 | .borrow_mut() | |
49aad941 FG |
3024 | .last_leaf_edge() |
3025 | .next_back_kv() | |
9ffffee4 FG |
3026 | .ok()? |
3027 | .into_kv_valmut() | |
3028 | } | |
3029 | Some(current) => { | |
3030 | // SAFETY: We're not using this to mutate the tree. | |
3031 | unsafe { current.reborrow_mut() } | |
3032 | .next_back_leaf_edge() | |
3033 | .next_back_kv() | |
3034 | .ok()? | |
3035 | .into_kv_valmut() | |
3036 | } | |
3037 | }; | |
3038 | Some((k, v)) | |
3039 | } | |
3040 | ||
3041 | /// Returns a read-only cursor pointing to the current element. | |
3042 | /// | |
3043 | /// The lifetime of the returned `Cursor` is bound to that of the | |
3044 | /// `CursorMut`, which means it cannot outlive the `CursorMut` and that the | |
3045 | /// `CursorMut` is frozen for the lifetime of the `Cursor`. | |
3046 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3047 | pub fn as_cursor(&self) -> Cursor<'_, K, V> { | |
3048 | Cursor { | |
3049 | // SAFETY: The tree is immutable while the cursor exists. | |
3050 | root: unsafe { self.root.reborrow_shared().as_ref() }, | |
3051 | current: self.current.as_ref().map(|current| current.reborrow()), | |
3052 | } | |
3053 | } | |
3054 | } | |
3055 | ||
3056 | // Now the tree editing operations | |
3057 | impl<'a, K: Ord, V, A: Allocator + Clone> CursorMut<'a, K, V, A> { | |
3058 | /// Inserts a new element into the `BTreeMap` after the current one. | |
3059 | /// | |
3060 | /// If the cursor is pointing at the "ghost" non-element then the new element is | |
3061 | /// inserted at the front of the `BTreeMap`. | |
3062 | /// | |
3063 | /// # Safety | |
3064 | /// | |
3065 | /// You must ensure that the `BTreeMap` invariants are maintained. | |
3066 | /// Specifically: | |
3067 | /// | |
3068 | /// * The key of the newly inserted element must be unique in the tree. | |
3069 | /// * All keys in the tree must remain in sorted order. | |
3070 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3071 | pub unsafe fn insert_after_unchecked(&mut self, key: K, value: V) { | |
3072 | let edge = match self.current.take() { | |
3073 | None => { | |
3074 | // SAFETY: We have no other reference to the tree. | |
3075 | match unsafe { self.root.reborrow() } { | |
3076 | root @ None => { | |
3077 | // Tree is empty, allocate a new root. | |
3078 | let mut node = NodeRef::new_leaf(self.alloc.clone()); | |
3079 | node.borrow_mut().push(key, value); | |
3080 | *root = Some(node.forget_type()); | |
3081 | *self.length += 1; | |
3082 | return; | |
3083 | } | |
3084 | Some(root) => root.borrow_mut().first_leaf_edge(), | |
3085 | } | |
3086 | } | |
3087 | Some(current) => current.next_leaf_edge(), | |
3088 | }; | |
3089 | ||
3090 | let handle = edge.insert_recursing(key, value, self.alloc.clone(), |ins| { | |
3091 | drop(ins.left); | |
3092 | // SAFETY: The handle to the newly inserted value is always on a | |
3093 | // leaf node, so adding a new root node doesn't invalidate it. | |
3094 | let root = unsafe { self.root.reborrow().as_mut().unwrap() }; | |
3095 | root.push_internal_level(self.alloc.clone()).push(ins.kv.0, ins.kv.1, ins.right) | |
3096 | }); | |
3097 | self.current = handle.left_edge().next_back_kv().ok(); | |
3098 | *self.length += 1; | |
3099 | } | |
3100 | ||
3101 | /// Inserts a new element into the `BTreeMap` before the current one. | |
3102 | /// | |
3103 | /// If the cursor is pointing at the "ghost" non-element then the new element is | |
3104 | /// inserted at the end of the `BTreeMap`. | |
3105 | /// | |
3106 | /// # Safety | |
3107 | /// | |
3108 | /// You must ensure that the `BTreeMap` invariants are maintained. | |
3109 | /// Specifically: | |
3110 | /// | |
3111 | /// * The key of the newly inserted element must be unique in the tree. | |
3112 | /// * All keys in the tree must remain in sorted order. | |
3113 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3114 | pub unsafe fn insert_before_unchecked(&mut self, key: K, value: V) { | |
3115 | let edge = match self.current.take() { | |
3116 | None => { | |
3117 | // SAFETY: We have no other reference to the tree. | |
3118 | match unsafe { self.root.reborrow() } { | |
3119 | root @ None => { | |
3120 | // Tree is empty, allocate a new root. | |
3121 | let mut node = NodeRef::new_leaf(self.alloc.clone()); | |
3122 | node.borrow_mut().push(key, value); | |
3123 | *root = Some(node.forget_type()); | |
3124 | *self.length += 1; | |
3125 | return; | |
3126 | } | |
3127 | Some(root) => root.borrow_mut().last_leaf_edge(), | |
3128 | } | |
3129 | } | |
3130 | Some(current) => current.next_back_leaf_edge(), | |
3131 | }; | |
3132 | ||
3133 | let handle = edge.insert_recursing(key, value, self.alloc.clone(), |ins| { | |
3134 | drop(ins.left); | |
3135 | // SAFETY: The handle to the newly inserted value is always on a | |
3136 | // leaf node, so adding a new root node doesn't invalidate it. | |
3137 | let root = unsafe { self.root.reborrow().as_mut().unwrap() }; | |
3138 | root.push_internal_level(self.alloc.clone()).push(ins.kv.0, ins.kv.1, ins.right) | |
3139 | }); | |
3140 | self.current = handle.right_edge().next_kv().ok(); | |
3141 | *self.length += 1; | |
3142 | } | |
3143 | ||
3144 | /// Inserts a new element into the `BTreeMap` after the current one. | |
3145 | /// | |
3146 | /// If the cursor is pointing at the "ghost" non-element then the new element is | |
3147 | /// inserted at the front of the `BTreeMap`. | |
3148 | /// | |
3149 | /// # Panics | |
3150 | /// | |
3151 | /// This function panics if: | |
3152 | /// - the given key compares less than or equal to the current element (if | |
3153 | /// any). | |
3154 | /// - the given key compares greater than or equal to the next element (if | |
3155 | /// any). | |
3156 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3157 | pub fn insert_after(&mut self, key: K, value: V) { | |
3158 | if let Some(current) = self.key() { | |
3159 | if &key <= current { | |
3160 | panic!("key must be ordered above the current element"); | |
3161 | } | |
3162 | } | |
353b0b11 | 3163 | if let Some((next, _)) = self.peek_next() { |
9ffffee4 FG |
3164 | if &key >= next { |
3165 | panic!("key must be ordered below the next element"); | |
3166 | } | |
3167 | } | |
3168 | unsafe { | |
3169 | self.insert_after_unchecked(key, value); | |
3170 | } | |
3171 | } | |
3172 | ||
3173 | /// Inserts a new element into the `BTreeMap` before the current one. | |
3174 | /// | |
3175 | /// If the cursor is pointing at the "ghost" non-element then the new element is | |
3176 | /// inserted at the end of the `BTreeMap`. | |
3177 | /// | |
3178 | /// # Panics | |
3179 | /// | |
3180 | /// This function panics if: | |
3181 | /// - the given key compares greater than or equal to the current element | |
3182 | /// (if any). | |
3183 | /// - the given key compares less than or equal to the previous element (if | |
3184 | /// any). | |
3185 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3186 | pub fn insert_before(&mut self, key: K, value: V) { | |
3187 | if let Some(current) = self.key() { | |
3188 | if &key >= current { | |
3189 | panic!("key must be ordered below the current element"); | |
3190 | } | |
3191 | } | |
3192 | if let Some((prev, _)) = self.peek_prev() { | |
3193 | if &key <= prev { | |
3194 | panic!("key must be ordered above the previous element"); | |
3195 | } | |
3196 | } | |
3197 | unsafe { | |
3198 | self.insert_before_unchecked(key, value); | |
3199 | } | |
3200 | } | |
3201 | ||
3202 | /// Removes the current element from the `BTreeMap`. | |
3203 | /// | |
3204 | /// The element that was removed is returned, and the cursor is | |
3205 | /// moved to point to the next element in the `BTreeMap`. | |
3206 | /// | |
3207 | /// If the cursor is currently pointing to the "ghost" non-element then no element | |
3208 | /// is removed and `None` is returned. The cursor is not moved in this case. | |
3209 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3210 | pub fn remove_current(&mut self) -> Option<(K, V)> { | |
3211 | let current = self.current.take()?; | |
3212 | let mut emptied_internal_root = false; | |
3213 | let (kv, pos) = | |
3214 | current.remove_kv_tracking(|| emptied_internal_root = true, self.alloc.clone()); | |
3215 | self.current = pos.next_kv().ok(); | |
3216 | *self.length -= 1; | |
3217 | if emptied_internal_root { | |
3218 | // SAFETY: This is safe since current does not point within the now | |
3219 | // empty root node. | |
3220 | let root = unsafe { self.root.reborrow().as_mut().unwrap() }; | |
3221 | root.pop_internal_level(self.alloc.clone()); | |
3222 | } | |
3223 | Some(kv) | |
3224 | } | |
3225 | ||
3226 | /// Removes the current element from the `BTreeMap`. | |
3227 | /// | |
3228 | /// The element that was removed is returned, and the cursor is | |
3229 | /// moved to point to the previous element in the `BTreeMap`. | |
3230 | /// | |
3231 | /// If the cursor is currently pointing to the "ghost" non-element then no element | |
3232 | /// is removed and `None` is returned. The cursor is not moved in this case. | |
3233 | #[unstable(feature = "btree_cursors", issue = "107540")] | |
3234 | pub fn remove_current_and_move_back(&mut self) -> Option<(K, V)> { | |
3235 | let current = self.current.take()?; | |
3236 | let mut emptied_internal_root = false; | |
3237 | let (kv, pos) = | |
3238 | current.remove_kv_tracking(|| emptied_internal_root = true, self.alloc.clone()); | |
3239 | self.current = pos.next_back_kv().ok(); | |
3240 | *self.length -= 1; | |
3241 | if emptied_internal_root { | |
3242 | // SAFETY: This is safe since current does not point within the now | |
3243 | // empty root node. | |
3244 | let root = unsafe { self.root.reborrow().as_mut().unwrap() }; | |
3245 | root.pop_internal_level(self.alloc.clone()); | |
3246 | } | |
3247 | Some(kv) | |
3248 | } | |
1a4d82fc JJ |
3249 | } |
3250 | ||
3dfed10e XL |
3251 | #[cfg(test)] |
3252 | mod tests; |