1use std::{cmp::Ordering, fmt::Debug};
2
3use crate::{Bias, Dimension, Edit, Item, KeyedItem, SeekTarget, SumTree, Summary};
4
5#[derive(Clone, PartialEq, Eq)]
6pub struct TreeMap<K, V>(SumTree<MapEntry<K, V>>)
7where
8 K: Clone + Debug + Ord,
9 V: Clone + Debug;
10
11#[derive(Clone, Debug, PartialEq, Eq)]
12pub struct MapEntry<K, V> {
13 key: K,
14 value: V,
15}
16
17#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
18pub struct MapKey<K>(Option<K>);
19
20impl<K> Default for MapKey<K> {
21 fn default() -> Self {
22 Self(None)
23 }
24}
25
26#[derive(Clone, Debug)]
27pub struct MapKeyRef<'a, K>(Option<&'a K>);
28
29impl<'a, K> Default for MapKeyRef<'a, K> {
30 fn default() -> Self {
31 Self(None)
32 }
33}
34
35#[derive(Clone)]
36pub struct TreeSet<K>(TreeMap<K, ()>)
37where
38 K: Clone + Debug + Ord;
39
40impl<K: Clone + Debug + Ord, V: Clone + Debug> TreeMap<K, V> {
41 pub fn from_ordered_entries(entries: impl IntoIterator<Item = (K, V)>) -> Self {
42 let tree = SumTree::from_iter(
43 entries
44 .into_iter()
45 .map(|(key, value)| MapEntry { key, value }),
46 &(),
47 );
48 Self(tree)
49 }
50
51 pub fn is_empty(&self) -> bool {
52 self.0.is_empty()
53 }
54
55 pub fn get(&self, key: &K) -> Option<&V> {
56 let mut cursor = self.0.cursor::<MapKeyRef<'_, K>>();
57 cursor.seek(&MapKeyRef(Some(key)), Bias::Left, &());
58 if let Some(item) = cursor.item() {
59 if Some(key) == item.key().0.as_ref() {
60 Some(&item.value)
61 } else {
62 None
63 }
64 } else {
65 None
66 }
67 }
68
69 pub fn insert(&mut self, key: K, value: V) {
70 self.0.insert_or_replace(MapEntry { key, value }, &());
71 }
72
73 pub fn remove(&mut self, key: &K) -> Option<V> {
74 let mut removed = None;
75 let mut cursor = self.0.cursor::<MapKeyRef<'_, K>>();
76 let key = MapKeyRef(Some(key));
77 let mut new_tree = cursor.slice(&key, Bias::Left, &());
78 if key.cmp(&cursor.end(&()), &()) == Ordering::Equal {
79 removed = Some(cursor.item().unwrap().value.clone());
80 cursor.next(&());
81 }
82 new_tree.append(cursor.suffix(&()), &());
83 drop(cursor);
84 self.0 = new_tree;
85 removed
86 }
87
88 pub fn remove_range(&mut self, start: &impl MapSeekTarget<K>, end: &impl MapSeekTarget<K>) {
89 let start = MapSeekTargetAdaptor(start);
90 let end = MapSeekTargetAdaptor(end);
91 let mut cursor = self.0.cursor::<MapKeyRef<'_, K>>();
92 let mut new_tree = cursor.slice(&start, Bias::Left, &());
93 cursor.seek(&end, Bias::Left, &());
94 new_tree.append(cursor.suffix(&()), &());
95 drop(cursor);
96 self.0 = new_tree;
97 }
98
99 /// Returns the key-value pair with the greatest key less than or equal to the given key.
100 pub fn closest(&self, key: &K) -> Option<(&K, &V)> {
101 let mut cursor = self.0.cursor::<MapKeyRef<'_, K>>();
102 let key = MapKeyRef(Some(key));
103 cursor.seek(&key, Bias::Right, &());
104 cursor.prev(&());
105 cursor.item().map(|item| (&item.key, &item.value))
106 }
107
108 pub fn iter_from<'a>(&'a self, from: &'a K) -> impl Iterator<Item = (&K, &V)> + '_ {
109 let mut cursor = self.0.cursor::<MapKeyRef<'_, K>>();
110 let from_key = MapKeyRef(Some(from));
111 cursor.seek(&from_key, Bias::Left, &());
112
113 cursor.map(|map_entry| (&map_entry.key, &map_entry.value))
114 }
115
116 pub fn update<F, T>(&mut self, key: &K, f: F) -> Option<T>
117 where
118 F: FnOnce(&mut V) -> T,
119 {
120 let mut cursor = self.0.cursor::<MapKeyRef<'_, K>>();
121 let key = MapKeyRef(Some(key));
122 let mut new_tree = cursor.slice(&key, Bias::Left, &());
123 let mut result = None;
124 if key.cmp(&cursor.end(&()), &()) == Ordering::Equal {
125 let mut updated = cursor.item().unwrap().clone();
126 result = Some(f(&mut updated.value));
127 new_tree.push(updated, &());
128 cursor.next(&());
129 }
130 new_tree.append(cursor.suffix(&()), &());
131 drop(cursor);
132 self.0 = new_tree;
133 result
134 }
135
136 pub fn retain<F: FnMut(&K, &V) -> bool>(&mut self, mut predicate: F) {
137 let mut new_map = SumTree::<MapEntry<K, V>>::default();
138
139 let mut cursor = self.0.cursor::<MapKeyRef<'_, K>>();
140 cursor.next(&());
141 while let Some(item) = cursor.item() {
142 if predicate(&item.key, &item.value) {
143 new_map.push(item.clone(), &());
144 }
145 cursor.next(&());
146 }
147 drop(cursor);
148
149 self.0 = new_map;
150 }
151
152 pub fn iter(&self) -> impl Iterator<Item = (&K, &V)> + '_ {
153 self.0.iter().map(|entry| (&entry.key, &entry.value))
154 }
155
156 pub fn values(&self) -> impl Iterator<Item = &V> + '_ {
157 self.0.iter().map(|entry| &entry.value)
158 }
159
160 pub fn insert_tree(&mut self, other: TreeMap<K, V>) {
161 let edits = other
162 .iter()
163 .map(|(key, value)| {
164 Edit::Insert(MapEntry {
165 key: key.to_owned(),
166 value: value.to_owned(),
167 })
168 })
169 .collect();
170
171 self.0.edit(edits, &());
172 }
173}
174
175impl<K: Debug, V: Debug> Debug for TreeMap<K, V>
176where
177 K: Clone + Debug + Ord,
178 V: Clone + Debug,
179{
180 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
181 f.debug_map().entries(self.iter()).finish()
182 }
183}
184
185#[derive(Debug)]
186struct MapSeekTargetAdaptor<'a, T>(&'a T);
187
188impl<'a, K: Debug + Clone + Ord, T: MapSeekTarget<K>> SeekTarget<'a, MapKey<K>, MapKeyRef<'a, K>>
189 for MapSeekTargetAdaptor<'_, T>
190{
191 fn cmp(&self, cursor_location: &MapKeyRef<K>, _: &()) -> Ordering {
192 if let Some(key) = &cursor_location.0 {
193 MapSeekTarget::cmp_cursor(self.0, key)
194 } else {
195 Ordering::Greater
196 }
197 }
198}
199
200pub trait MapSeekTarget<K>: Debug {
201 fn cmp_cursor(&self, cursor_location: &K) -> Ordering;
202}
203
204impl<K: Debug + Ord> MapSeekTarget<K> for K {
205 fn cmp_cursor(&self, cursor_location: &K) -> Ordering {
206 self.cmp(cursor_location)
207 }
208}
209
210impl<K, V> Default for TreeMap<K, V>
211where
212 K: Clone + Debug + Ord,
213 V: Clone + Debug,
214{
215 fn default() -> Self {
216 Self(Default::default())
217 }
218}
219
220impl<K, V> Item for MapEntry<K, V>
221where
222 K: Clone + Debug + Ord,
223 V: Clone,
224{
225 type Summary = MapKey<K>;
226
227 fn summary(&self) -> Self::Summary {
228 self.key()
229 }
230}
231
232impl<K, V> KeyedItem for MapEntry<K, V>
233where
234 K: Clone + Debug + Ord,
235 V: Clone,
236{
237 type Key = MapKey<K>;
238
239 fn key(&self) -> Self::Key {
240 MapKey(Some(self.key.clone()))
241 }
242}
243
244impl<K> Summary for MapKey<K>
245where
246 K: Clone + Debug,
247{
248 type Context = ();
249
250 fn add_summary(&mut self, summary: &Self, _: &()) {
251 *self = summary.clone()
252 }
253}
254
255impl<'a, K> Dimension<'a, MapKey<K>> for MapKeyRef<'a, K>
256where
257 K: Clone + Debug + Ord,
258{
259 fn add_summary(&mut self, summary: &'a MapKey<K>, _: &()) {
260 self.0 = summary.0.as_ref();
261 }
262}
263
264impl<'a, K> SeekTarget<'a, MapKey<K>, MapKeyRef<'a, K>> for MapKeyRef<'_, K>
265where
266 K: Clone + Debug + Ord,
267{
268 fn cmp(&self, cursor_location: &MapKeyRef<K>, _: &()) -> Ordering {
269 Ord::cmp(&self.0, &cursor_location.0)
270 }
271}
272
273impl<K> Default for TreeSet<K>
274where
275 K: Clone + Debug + Ord,
276{
277 fn default() -> Self {
278 Self(Default::default())
279 }
280}
281
282impl<K> TreeSet<K>
283where
284 K: Clone + Debug + Ord,
285{
286 pub fn from_ordered_entries(entries: impl IntoIterator<Item = K>) -> Self {
287 Self(TreeMap::from_ordered_entries(
288 entries.into_iter().map(|key| (key, ())),
289 ))
290 }
291
292 pub fn insert(&mut self, key: K) {
293 self.0.insert(key, ());
294 }
295
296 pub fn contains(&self, key: &K) -> bool {
297 self.0.get(key).is_some()
298 }
299
300 pub fn iter(&self) -> impl Iterator<Item = &K> + '_ {
301 self.0.iter().map(|(k, _)| k)
302 }
303}
304
305#[cfg(test)]
306mod tests {
307 use super::*;
308
309 #[test]
310 fn test_basic() {
311 let mut map = TreeMap::default();
312 assert_eq!(map.iter().collect::<Vec<_>>(), vec![]);
313
314 map.insert(3, "c");
315 assert_eq!(map.get(&3), Some(&"c"));
316 assert_eq!(map.iter().collect::<Vec<_>>(), vec![(&3, &"c")]);
317
318 map.insert(1, "a");
319 assert_eq!(map.get(&1), Some(&"a"));
320 assert_eq!(map.iter().collect::<Vec<_>>(), vec![(&1, &"a"), (&3, &"c")]);
321
322 map.insert(2, "b");
323 assert_eq!(map.get(&2), Some(&"b"));
324 assert_eq!(map.get(&1), Some(&"a"));
325 assert_eq!(map.get(&3), Some(&"c"));
326 assert_eq!(
327 map.iter().collect::<Vec<_>>(),
328 vec![(&1, &"a"), (&2, &"b"), (&3, &"c")]
329 );
330
331 assert_eq!(map.closest(&0), None);
332 assert_eq!(map.closest(&1), Some((&1, &"a")));
333 assert_eq!(map.closest(&10), Some((&3, &"c")));
334
335 map.remove(&2);
336 assert_eq!(map.get(&2), None);
337 assert_eq!(map.iter().collect::<Vec<_>>(), vec![(&1, &"a"), (&3, &"c")]);
338
339 assert_eq!(map.closest(&2), Some((&1, &"a")));
340
341 map.remove(&3);
342 assert_eq!(map.get(&3), None);
343 assert_eq!(map.iter().collect::<Vec<_>>(), vec![(&1, &"a")]);
344
345 map.remove(&1);
346 assert_eq!(map.get(&1), None);
347 assert_eq!(map.iter().collect::<Vec<_>>(), vec![]);
348
349 map.insert(4, "d");
350 map.insert(5, "e");
351 map.insert(6, "f");
352 map.retain(|key, _| *key % 2 == 0);
353 assert_eq!(map.iter().collect::<Vec<_>>(), vec![(&4, &"d"), (&6, &"f")]);
354 }
355
356 #[test]
357 fn test_iter_from() {
358 let mut map = TreeMap::default();
359
360 map.insert("a", 1);
361 map.insert("b", 2);
362 map.insert("baa", 3);
363 map.insert("baaab", 4);
364 map.insert("c", 5);
365
366 let result = map
367 .iter_from(&"ba")
368 .take_while(|(key, _)| key.starts_with(&"ba"))
369 .collect::<Vec<_>>();
370
371 assert_eq!(result.len(), 2);
372 assert!(result.iter().any(|(k, _)| k == &&"baa"));
373 assert!(result.iter().any(|(k, _)| k == &&"baaab"));
374
375 let result = map
376 .iter_from(&"c")
377 .take_while(|(key, _)| key.starts_with(&"c"))
378 .collect::<Vec<_>>();
379
380 assert_eq!(result.len(), 1);
381 assert!(result.iter().any(|(k, _)| k == &&"c"));
382 }
383
384 #[test]
385 fn test_insert_tree() {
386 let mut map = TreeMap::default();
387 map.insert("a", 1);
388 map.insert("b", 2);
389 map.insert("c", 3);
390
391 let mut other = TreeMap::default();
392 other.insert("a", 2);
393 other.insert("b", 2);
394 other.insert("d", 4);
395
396 map.insert_tree(other);
397
398 assert_eq!(map.iter().count(), 4);
399 assert_eq!(map.get(&"a"), Some(&2));
400 assert_eq!(map.get(&"b"), Some(&2));
401 assert_eq!(map.get(&"c"), Some(&3));
402 assert_eq!(map.get(&"d"), Some(&4));
403 }
404
405 #[test]
406 fn test_remove_between_and_path_successor() {
407 use std::path::{Path, PathBuf};
408
409 #[derive(Debug)]
410 pub struct PathDescendants<'a>(&'a Path);
411
412 impl MapSeekTarget<PathBuf> for PathDescendants<'_> {
413 fn cmp_cursor(&self, key: &PathBuf) -> Ordering {
414 if key.starts_with(&self.0) {
415 Ordering::Greater
416 } else {
417 self.0.cmp(key)
418 }
419 }
420 }
421
422 let mut map = TreeMap::default();
423
424 map.insert(PathBuf::from("a"), 1);
425 map.insert(PathBuf::from("a/a"), 1);
426 map.insert(PathBuf::from("b"), 2);
427 map.insert(PathBuf::from("b/a/a"), 3);
428 map.insert(PathBuf::from("b/a/a/a/b"), 4);
429 map.insert(PathBuf::from("c"), 5);
430 map.insert(PathBuf::from("c/a"), 6);
431
432 map.remove_range(
433 &PathBuf::from("b/a"),
434 &PathDescendants(&PathBuf::from("b/a")),
435 );
436
437 assert_eq!(map.get(&PathBuf::from("a")), Some(&1));
438 assert_eq!(map.get(&PathBuf::from("a/a")), Some(&1));
439 assert_eq!(map.get(&PathBuf::from("b")), Some(&2));
440 assert_eq!(map.get(&PathBuf::from("b/a/a")), None);
441 assert_eq!(map.get(&PathBuf::from("b/a/a/a/b")), None);
442 assert_eq!(map.get(&PathBuf::from("c")), Some(&5));
443 assert_eq!(map.get(&PathBuf::from("c/a")), Some(&6));
444
445 map.remove_range(&PathBuf::from("c"), &PathDescendants(&PathBuf::from("c")));
446
447 assert_eq!(map.get(&PathBuf::from("a")), Some(&1));
448 assert_eq!(map.get(&PathBuf::from("a/a")), Some(&1));
449 assert_eq!(map.get(&PathBuf::from("b")), Some(&2));
450 assert_eq!(map.get(&PathBuf::from("c")), None);
451 assert_eq!(map.get(&PathBuf::from("c/a")), None);
452
453 map.remove_range(&PathBuf::from("a"), &PathDescendants(&PathBuf::from("a")));
454
455 assert_eq!(map.get(&PathBuf::from("a")), None);
456 assert_eq!(map.get(&PathBuf::from("a/a")), None);
457 assert_eq!(map.get(&PathBuf::from("b")), Some(&2));
458
459 map.remove_range(&PathBuf::from("b"), &PathDescendants(&PathBuf::from("b")));
460
461 assert_eq!(map.get(&PathBuf::from("b")), None);
462 }
463}