Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1 | //! A hash map where the keys are held by weak pointers and compared by key value. |
| 2 | |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 3 | use super::*; |
| 4 | use super::size_policy::*; |
| 5 | use super::traits::*; |
| 6 | use super::util::*; |
| 7 | |
| 8 | pub use super::WeakKeyHashMap; |
| 9 | |
| 10 | /// Represents an entry in the table which may be occupied or vacant. |
| 11 | pub enum Entry<'a, K: 'a + WeakKey, V: 'a> { |
| 12 | Occupied(OccupiedEntry<'a, K, V>), |
| 13 | Vacant(VacantEntry<'a, K, V>), |
| 14 | } |
| 15 | |
| 16 | /// An occupied entry, which can be removed or viewed. |
| 17 | pub struct OccupiedEntry<'a, K: 'a + WeakKey, V: 'a>(InnerEntry<'a, K, V>); |
| 18 | |
| 19 | /// A vacant entry, which can be inserted in or viewed. |
| 20 | pub struct VacantEntry<'a, K: 'a + WeakKey, V: 'a>(InnerEntry<'a, K, V>); |
| 21 | |
| 22 | struct InnerEntry<'a, K: 'a + WeakKey, V: 'a> { |
| 23 | map: &'a mut WeakKeyInnerMap<K, V>, |
| 24 | pos: usize, |
| 25 | key: K::Strong, |
| 26 | hash_code: HashCode, |
| 27 | } |
| 28 | |
| 29 | /// An iterator over the keys and values of the weak hash map. |
| 30 | #[derive(Clone, Debug)] |
| 31 | pub struct Iter<'a, K: 'a, V: 'a> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 32 | base: slice::Iter<'a, Bucket<K, V>>, |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 33 | size: usize, |
| 34 | } |
| 35 | |
| 36 | impl<'a, K: WeakElement, V> Iterator for Iter<'a, K, V> { |
| 37 | type Item = (K::Strong, &'a V); |
| 38 | |
| 39 | fn next(&mut self) -> Option<Self::Item> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 40 | for bucket in &mut self.base { |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 41 | if let Some((ref weak_ptr, ref value, _)) = *bucket { |
| 42 | self.size -= 1; |
| 43 | if let Some(strong_ptr) = weak_ptr.view() { |
| 44 | return Some((strong_ptr, value)); |
| 45 | } |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | None |
| 50 | } |
| 51 | |
| 52 | fn size_hint(&self) -> (usize, Option<usize>) { |
| 53 | (0, Some(self.size)) |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | #[derive(Debug)] |
| 58 | /// An iterator over the keys and mutable values of the weak hash map. |
| 59 | pub struct IterMut<'a, K: 'a, V: 'a> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 60 | base: slice::IterMut<'a, Bucket<K, V>>, |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 61 | size: usize, |
| 62 | } |
| 63 | |
| 64 | impl<'a, K: WeakElement, V> Iterator for IterMut<'a, K, V> { |
| 65 | type Item = (K::Strong, &'a mut V); |
| 66 | |
| 67 | fn next(&mut self) -> Option<Self::Item> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 68 | for bucket in &mut self.base { |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 69 | if let Some((ref weak_ptr, ref mut value, _)) = *bucket { |
| 70 | self.size -= 1; |
| 71 | if let Some(strong_ptr) = weak_ptr.view() { |
| 72 | return Some((strong_ptr, value)); |
| 73 | } |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | None |
| 78 | } |
| 79 | |
| 80 | fn size_hint(&self) -> (usize, Option<usize>) { |
| 81 | (0, Some(self.size)) |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | /// An iterator over the keys of the weak hash map. |
| 86 | #[derive(Clone, Debug)] |
| 87 | pub struct Keys<'a, K: 'a, V: 'a>(Iter<'a, K, V>); |
| 88 | |
| 89 | impl<'a, K: WeakElement, V> Iterator for Keys<'a, K, V> { |
| 90 | type Item = K::Strong; |
| 91 | |
| 92 | fn next(&mut self) -> Option<Self::Item> { |
| 93 | self.0.next().map(|(k, _)| k) |
| 94 | } |
| 95 | |
| 96 | fn size_hint(&self) -> (usize, Option<usize>) { |
| 97 | self.0.size_hint() |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | /// An iterator over the values of the weak hash map. |
| 102 | #[derive(Clone, Debug)] |
| 103 | pub struct Values<'a, K: 'a, V: 'a>(Iter<'a, K, V>); |
| 104 | |
| 105 | impl<'a, K: WeakElement, V> Iterator for Values<'a, K, V> { |
| 106 | type Item = &'a V; |
| 107 | |
| 108 | fn next(&mut self) -> Option<Self::Item> { |
| 109 | self.0.next().map(|(_, v)| v) |
| 110 | } |
| 111 | |
| 112 | fn size_hint(&self) -> (usize, Option<usize>) { |
| 113 | self.0.size_hint() |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | #[derive(Debug)] |
| 118 | /// An iterator over the mutable values of the weak hash map. |
| 119 | pub struct ValuesMut<'a, K: 'a, V: 'a>(IterMut<'a, K, V>); |
| 120 | |
| 121 | impl<'a, K: WeakElement, V> Iterator for ValuesMut<'a, K, V> { |
| 122 | type Item = &'a mut V; |
| 123 | |
| 124 | fn next(&mut self) -> Option<Self::Item> { |
| 125 | self.0.next().map(|(_, v)| v) |
| 126 | } |
| 127 | |
| 128 | fn size_hint(&self) -> (usize, Option<usize>) { |
| 129 | self.0.size_hint() |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | #[derive(Debug)] |
| 134 | /// An iterator that consumes the values of a weak hash map, leaving it empty. |
| 135 | pub struct Drain<'a, K: 'a, V: 'a> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 136 | base: slice::IterMut<'a, Bucket<K, V>>, |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 137 | size: usize, |
| 138 | } |
| 139 | |
| 140 | impl<'a, K: WeakElement, V> Iterator for Drain<'a, K, V> { |
| 141 | type Item = (K::Strong, V); |
| 142 | |
| 143 | fn next(&mut self) -> Option<Self::Item> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 144 | for bucket in &mut self.base { |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 145 | if let Some((weak_ptr, value, _)) = bucket.take() { |
| 146 | self.size -= 1; |
| 147 | if let Some(strong_ptr) = weak_ptr.view() { |
| 148 | return Some((strong_ptr, value)); |
| 149 | } |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | None |
| 154 | } |
| 155 | |
| 156 | fn size_hint(&self) -> (usize, Option<usize>) { |
| 157 | (0, Some(self.size)) |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | impl<'a, K, V> Drop for Drain<'a, K, V> { |
| 162 | fn drop(&mut self) { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 163 | for option in &mut self.base { |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 164 | *option = None; |
| 165 | } |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | /// An iterator that consumes the values of a weak hash map, leaving it empty. |
| 170 | pub struct IntoIter<K, V> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 171 | base: vec::IntoIter<Bucket<K, V>>, |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 172 | size: usize, |
| 173 | } |
| 174 | |
| 175 | impl<K: WeakElement, V> Iterator for IntoIter<K, V> { |
| 176 | type Item = (K::Strong, V); |
| 177 | |
| 178 | fn next(&mut self) -> Option<Self::Item> { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 179 | for (weak_ptr, value, _) in (&mut self.base).flatten() { |
| 180 | self.size -= 1; |
| 181 | if let Some(strong_ptr) = weak_ptr.view() { |
| 182 | return Some((strong_ptr, value)); |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 183 | } |
| 184 | } |
| 185 | |
| 186 | None |
| 187 | } |
| 188 | |
| 189 | fn size_hint(&self) -> (usize, Option<usize>) { |
| 190 | (0, Some(self.size)) |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | impl<K: WeakKey, V> WeakKeyHashMap<K, V, RandomState> |
| 195 | { |
| 196 | /// Creates an empty `WeakKeyHashMap`. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 197 | /// |
| 198 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 199 | pub fn new() -> Self { |
| 200 | Self::with_capacity(DEFAULT_INITIAL_CAPACITY) |
| 201 | } |
| 202 | |
| 203 | /// Creates an empty `WeakKeyHashMap` with the given capacity. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 204 | /// |
| 205 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 206 | pub fn with_capacity(capacity: usize) -> Self { |
| 207 | Self::with_capacity_and_hasher(capacity, Default::default()) |
| 208 | } |
| 209 | } |
| 210 | |
| 211 | impl<K: WeakKey, V, S: BuildHasher> WeakKeyHashMap<K, V, S> |
| 212 | { |
| 213 | /// Creates an empty `WeakKeyHashMap` with the given capacity and hasher. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 214 | /// |
| 215 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 216 | pub fn with_hasher(hash_builder: S) -> Self { |
| 217 | Self::with_capacity_and_hasher(DEFAULT_INITIAL_CAPACITY, hash_builder) |
| 218 | } |
| 219 | |
| 220 | /// Creates an empty `WeakKeyHashMap` with the given capacity and hasher. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 221 | /// |
| 222 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 223 | pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> Self { |
| 224 | WeakKeyHashMap { |
| 225 | hash_builder, |
| 226 | inner: WeakKeyInnerMap { |
| 227 | buckets: new_boxed_option_slice(capacity), |
| 228 | len: 0, |
| 229 | } |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | /// Returns a reference to the map's `BuildHasher`. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 234 | /// |
| 235 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 236 | pub fn hasher(&self) -> &S { |
| 237 | &self.hash_builder |
| 238 | } |
| 239 | |
| 240 | /// Returns the number of elements the map can hold without reallocating. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 241 | /// |
| 242 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 243 | pub fn capacity(&self) -> usize { |
| 244 | self.inner.capacity() |
| 245 | } |
| 246 | |
| 247 | /// This has some preconditions. |
| 248 | fn resize(&mut self, capacity: usize) { |
| 249 | let old_buckets = mem::replace(&mut self.inner.buckets, |
| 250 | new_boxed_option_slice(capacity)); |
| 251 | |
| 252 | let iter = IntoIter { |
| 253 | base: old_buckets.into_vec().into_iter(), |
| 254 | size: self.inner.len, |
| 255 | }; |
| 256 | |
| 257 | self.inner.len = 0; |
| 258 | |
| 259 | for (key, value) in iter { |
| 260 | self.entry_no_grow(key).or_insert(value); |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | /// Removes all mappings whose keys have expired. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 265 | /// |
| 266 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 267 | pub fn remove_expired(&mut self) { |
| 268 | self.retain(|_, _| true) |
| 269 | } |
| 270 | |
| 271 | /// Reserves room for additional elements. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 272 | /// |
| 273 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 274 | pub fn reserve(&mut self, additional_capacity: usize) { |
| 275 | let new_capacity = additional_capacity + self.capacity(); |
| 276 | self.resize(new_capacity); |
| 277 | } |
| 278 | |
| 279 | /// Shrinks the capacity to the minimum allowed to hold the current number of elements. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 280 | /// |
| 281 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 282 | pub fn shrink_to_fit(&mut self) { |
| 283 | self.remove_expired(); |
| 284 | let new_capacity = (self.len() as f32 / COLLECT_LOAD_FACTOR).ceil() as usize; |
| 285 | self.resize(new_capacity); |
| 286 | } |
| 287 | |
| 288 | /// Returns an over-approximation of the number of elements. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 289 | /// |
| 290 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 291 | pub fn len(&self) -> usize { |
| 292 | self.inner.len |
| 293 | } |
| 294 | |
| 295 | /// Is the map empty? |
| 296 | /// |
| 297 | /// Note that this may return false even if all keys in the map have |
| 298 | /// expired, if they haven't been collected yet. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 299 | /// |
| 300 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 301 | pub fn is_empty(&self) -> bool { |
| 302 | self.len() == 0 |
| 303 | } |
| 304 | |
| 305 | /// The proportion of buckets that are used. |
| 306 | /// |
| 307 | /// This is an over-approximation because of expired keys. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 308 | /// |
| 309 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 310 | pub fn load_factor(&self) -> f32 { |
| 311 | (self.len() as f32 + 1.0) / self.capacity() as f32 |
| 312 | } |
| 313 | |
| 314 | fn maybe_adjust_size(&mut self) { |
| 315 | if self.load_factor() > COLLECT_LOAD_FACTOR { |
| 316 | self.remove_expired(); |
| 317 | |
| 318 | let load_factor = self.load_factor(); |
| 319 | let capacity = self.capacity(); |
| 320 | if load_factor > GROW_LOAD_FACTOR { |
| 321 | self.resize(max(1, capacity * 2)); |
| 322 | } else if load_factor < SHRINK_LOAD_FACTOR && capacity > DEFAULT_INITIAL_CAPACITY { |
| 323 | self.resize(max(1, capacity / 2)); |
| 324 | } |
| 325 | } |
| 326 | } |
| 327 | |
| 328 | /// Gets the requested entry. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 329 | /// |
| 330 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 331 | pub fn entry(&mut self, key: K::Strong) -> Entry<K, V> { |
| 332 | self.maybe_adjust_size(); |
| 333 | self.entry_no_grow(key) |
| 334 | } |
| 335 | |
| 336 | fn entry_no_grow(&mut self, key: K::Strong) -> Entry<K, V> { |
| 337 | let mut inner = { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 338 | let hash_code = self.hash(&key, K::hash); |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 339 | InnerEntry { |
| 340 | pos: self.which_bucket(hash_code), |
| 341 | map: &mut self.inner, |
| 342 | hash_code, |
| 343 | key, |
| 344 | } |
| 345 | }; |
| 346 | |
| 347 | for dist in 0 .. inner.capacity() { |
| 348 | match inner.bucket_status() { |
| 349 | BucketStatus::Unoccupied => |
| 350 | return Entry::Vacant(VacantEntry(inner)), |
| 351 | BucketStatus::MatchesKey => |
| 352 | return Entry::Occupied(OccupiedEntry(inner)), |
| 353 | BucketStatus::ProbeDistance(bucket_distance) => { |
| 354 | if bucket_distance < dist { |
| 355 | return Entry::Vacant(VacantEntry(inner)) |
| 356 | } else { |
| 357 | inner.pos = inner.next_bucket(inner.pos); |
| 358 | } |
| 359 | } |
| 360 | } |
| 361 | } |
| 362 | |
| 363 | panic!("WeakKeyHashTable::entry: out of space"); |
| 364 | } |
| 365 | |
| 366 | /// Removes all associations from the map. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 367 | /// |
| 368 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 369 | pub fn clear(&mut self) { |
| 370 | self.drain(); |
| 371 | } |
| 372 | |
| 373 | fn find_bucket<Q>(&self, key: &Q) -> Option<(usize, K::Strong, HashCode)> |
| 374 | where Q: ?Sized + Hash + Eq, |
| 375 | K::Key: Borrow<Q> |
| 376 | { |
| 377 | if self.capacity() == 0 { return None; } |
| 378 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 379 | let hash_code = self.hash(key, Q::hash); |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 380 | let mut pos = self.which_bucket(hash_code); |
| 381 | |
| 382 | for dist in 0 .. self.capacity() { |
| 383 | if let Some((ref weak_key, _, bucket_hash_code)) = self.inner.buckets[pos] { |
| 384 | if bucket_hash_code == hash_code { |
| 385 | if let Some(bucket_key) = weak_key.view() { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 386 | if K::equals(&bucket_key, key) { |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 387 | return Some((pos, bucket_key, bucket_hash_code)); |
| 388 | } |
| 389 | } |
| 390 | } |
| 391 | |
| 392 | let bucket_dist = |
| 393 | self.probe_distance(pos, self.which_bucket(bucket_hash_code)); |
| 394 | if bucket_dist < dist { |
| 395 | return None; |
| 396 | } |
| 397 | } else { |
| 398 | return None; |
| 399 | } |
| 400 | |
| 401 | pos = self.next_bucket(pos); |
| 402 | } |
| 403 | |
| 404 | None |
| 405 | } |
| 406 | |
| 407 | /// Returns a reference to the value corresponding to the key. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 408 | /// |
| 409 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 410 | pub fn get<Q>(&self, key: &Q) -> Option<&V> |
| 411 | where Q: ?Sized + Hash + Eq, |
| 412 | K::Key: Borrow<Q> |
| 413 | { |
| 414 | self.find_bucket(key).and_then(move |tup| |
| 415 | self.inner.buckets[tup.0].as_ref().map(|bucket| &bucket.1)) |
| 416 | } |
| 417 | |
| 418 | /// Returns true if the map contains the specified key. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 419 | /// |
| 420 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 421 | pub fn contains_key<Q>(&self, key: &Q) -> bool |
| 422 | where Q: ?Sized + Hash + Eq, |
| 423 | K::Key: Borrow<Q> |
| 424 | { |
| 425 | self.find_bucket(key).is_some() |
| 426 | } |
| 427 | |
| 428 | /// Returns a strong reference to the key, if found. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 429 | /// |
| 430 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 431 | pub fn get_key<Q>(&self, key: &Q) -> Option<K::Strong> |
| 432 | where Q: ?Sized + Hash + Eq, |
| 433 | K::Key: Borrow<Q> |
| 434 | { |
| 435 | self.find_bucket(key).map(|tup| tup.1) |
| 436 | } |
| 437 | |
| 438 | /// Returns a pair of a strong reference to the key, and a reference to the value, if present. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 439 | /// |
| 440 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 441 | pub fn get_both<Q>(&self, key: &Q) -> Option<(K::Strong, &V)> |
| 442 | where Q: ?Sized + Hash + Eq, |
| 443 | K::Key: Borrow<Q> |
| 444 | { |
| 445 | self.find_bucket(key).and_then(move |tup| |
| 446 | self.inner.buckets[tup.0].as_ref().map(|bucket| (tup.1, &bucket.1))) |
| 447 | } |
| 448 | |
| 449 | /// Returns a mutable reference to the value corresponding to the key. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 450 | /// |
| 451 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 452 | pub fn get_mut<Q>(&mut self, key: &Q) -> Option<&mut V> |
| 453 | where Q: ?Sized + Hash + Eq, |
| 454 | K::Key: Borrow<Q> |
| 455 | { |
| 456 | self.find_bucket(key).and_then(move |tup| |
| 457 | self.inner.buckets[tup.0].as_mut().map(|bucket| &mut bucket.1)) |
| 458 | } |
| 459 | |
| 460 | /// Returns a pair of a strong reference to the key, and a mutable reference to the value, |
| 461 | /// if present. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 462 | /// |
| 463 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 464 | pub fn get_both_mut<Q>(&mut self, key: &Q) -> Option<(K::Strong, &mut V)> |
| 465 | where Q: ?Sized + Hash + Eq, |
| 466 | K::Key: Borrow<Q> |
| 467 | { |
| 468 | self.find_bucket(key).and_then(move |tup| |
| 469 | self.inner.buckets[tup.0].as_mut().map(|bucket| (tup.1, &mut bucket.1))) |
| 470 | } |
| 471 | |
| 472 | /// Unconditionally inserts the value, returning the old value if already present. |
| 473 | /// |
| 474 | /// Unlike `std::collections::HashMap`, this replaced the key even if occupied. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 475 | /// |
| 476 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 477 | pub fn insert(&mut self, key: K::Strong, value: V) -> Option<V> { |
| 478 | match self.entry(key) { |
| 479 | Entry::Occupied(mut occupied) => { |
| 480 | Some(occupied.insert(value)) |
| 481 | }, |
| 482 | Entry::Vacant(vacant) => { |
| 483 | vacant.insert(value); |
| 484 | None |
| 485 | } |
| 486 | } |
| 487 | } |
| 488 | |
| 489 | /// Removes the entry with the given key, if it exists, and returns the value. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 490 | /// |
| 491 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 492 | pub fn remove<Q>(&mut self, key: &Q) -> Option<V> |
| 493 | where Q: ?Sized + Hash + Eq, |
| 494 | K::Key: Borrow<Q> |
| 495 | { |
| 496 | self.find_bucket(key).map(|(pos, strong_key, hash_code)| { |
| 497 | OccupiedEntry(InnerEntry { |
| 498 | map: &mut self.inner, |
| 499 | pos, |
| 500 | key: strong_key, |
| 501 | hash_code, |
| 502 | }).remove() |
| 503 | }) |
| 504 | } |
| 505 | |
| 506 | /// Removes all mappings not satisfying the given predicate. |
| 507 | /// |
| 508 | /// Also removes any expired mappings. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 509 | /// |
| 510 | /// *O*(*n*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 511 | pub fn retain<F>(&mut self, mut f: F) |
| 512 | where F: FnMut(K::Strong, &mut V) -> bool |
| 513 | { |
| 514 | for i in 0 .. self.capacity() { |
| 515 | let remove = match self.inner.buckets[i] { |
| 516 | None => false, |
| 517 | Some(ref mut bucket) => |
| 518 | match bucket.0.view() { |
| 519 | None => true, |
| 520 | Some(key) => !f(key, &mut bucket.1), |
| 521 | } |
| 522 | }; |
| 523 | |
| 524 | if remove { |
| 525 | self.inner.remove_index(i); |
| 526 | } |
| 527 | } |
| 528 | } |
| 529 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 530 | /// Is this map a submap of the other under the given value comparison `cmp`? |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 531 | /// |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 532 | /// In particular, for every key `k` of `self`, |
| 533 | /// |
| 534 | /// - `k` must also be a key of `other` and |
| 535 | /// - `cmp(self[k], other[k])` must hold. |
| 536 | /// |
| 537 | /// expected *O*(*n*) time; worst-case *O*(*nq*) time (where *n* is |
| 538 | /// `self.capacity()` and *q* is the length of the probe sequences |
| 539 | /// in `other`) |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 540 | pub fn is_submap_with<F, S1, V1>(&self, other: &WeakKeyHashMap<K, V1, S1>, |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 541 | mut cmp: F) -> bool |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 542 | where F: FnMut(&V, &V1) -> bool, |
| 543 | S1: BuildHasher |
| 544 | { |
| 545 | for (key, value1) in self { |
| 546 | if let Some(value2) = K::with_key(&key, |k| other.get(k)) { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 547 | if !cmp(value1, value2) { |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 548 | return false; |
| 549 | } |
| 550 | } else { |
| 551 | return false; |
| 552 | } |
| 553 | } |
| 554 | |
| 555 | true |
| 556 | } |
| 557 | |
| 558 | /// Is `self` a submap of `other`? |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 559 | /// |
| 560 | /// expected *O*(*n*) time; worst-case *O*(*nq*) time (where *n* is |
| 561 | /// `self.capacity()` and *q* is the length of the probe sequences |
| 562 | /// in `other`) |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 563 | pub fn is_submap<V1, S1>(&self, other: &WeakKeyHashMap<K, V1, S1>) -> bool |
| 564 | where V: PartialEq<V1>, |
| 565 | S1: BuildHasher |
| 566 | { |
| 567 | self.is_submap_with(other, PartialEq::eq) |
| 568 | } |
| 569 | |
| 570 | /// Are the keys of `self` a subset of the keys of `other`? |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 571 | /// |
| 572 | /// expected *O*(*n*) time; worst-case *O*(*nq*) time (where *n* is |
| 573 | /// `self.capacity()` and *q* is the length of the probe sequences |
| 574 | /// in `other`) |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 575 | pub fn domain_is_subset<V1, S1>(&self, other: &WeakKeyHashMap<K, V1, S1>) -> bool |
| 576 | where S1: BuildHasher |
| 577 | { |
| 578 | self.is_submap_with(other, |_, _| true) |
| 579 | } |
| 580 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 581 | fn hash<Q, H>(&self, key: Q, hash: H) -> HashCode |
| 582 | where H: FnOnce(Q, &mut S::Hasher) |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 583 | { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 584 | let hasher = &mut self.hash_builder.build_hasher(); |
| 585 | hash(key, hasher); |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 586 | HashCode(hasher.finish()) |
| 587 | } |
| 588 | } |
| 589 | |
| 590 | impl<K, V, V1, S, S1> PartialEq<WeakKeyHashMap<K, V1, S1>> for WeakKeyHashMap<K, V, S> |
| 591 | where K: WeakKey, |
| 592 | V: PartialEq<V1>, |
| 593 | S: BuildHasher, |
| 594 | S1: BuildHasher |
| 595 | { |
| 596 | fn eq(&self, other: &WeakKeyHashMap<K, V1, S1>) -> bool { |
| 597 | self.is_submap(other) && other.domain_is_subset(self) |
| 598 | } |
| 599 | } |
| 600 | |
| 601 | impl<K: WeakKey, V: Eq, S: BuildHasher> Eq for WeakKeyHashMap<K, V, S> { } |
| 602 | |
| 603 | impl<K: WeakKey, V, S: BuildHasher + Default> Default for WeakKeyHashMap<K, V, S> { |
| 604 | fn default() -> Self { |
| 605 | WeakKeyHashMap::with_hasher(Default::default()) |
| 606 | } |
| 607 | } |
| 608 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 609 | impl<'a, K, V, S, Q> ops::Index<&'a Q> for WeakKeyHashMap<K, V, S> |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 610 | where K: WeakKey, |
| 611 | K::Key: Borrow<Q>, |
| 612 | S: BuildHasher, |
| 613 | Q: ?Sized + Eq + Hash |
| 614 | { |
| 615 | type Output = V; |
| 616 | |
| 617 | fn index(&self, index: &'a Q) -> &Self::Output { |
| 618 | self.get(index).expect("Index::index: key not found") |
| 619 | } |
| 620 | } |
| 621 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 622 | impl<'a, K, V, S, Q> ops::IndexMut<&'a Q> for WeakKeyHashMap<K, V, S> |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 623 | where K: WeakKey, |
| 624 | K::Key: Borrow<Q>, |
| 625 | S: BuildHasher, |
| 626 | Q: ?Sized + Eq + Hash |
| 627 | { |
| 628 | fn index_mut(&mut self, index: &'a Q) -> &mut Self::Output { |
| 629 | self.get_mut(index).expect("IndexMut::index_mut: key not found") |
| 630 | } |
| 631 | } |
| 632 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 633 | impl<K, V, S> iter::FromIterator<(K::Strong, V)> for WeakKeyHashMap<K, V, S> |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 634 | where K: WeakKey, |
| 635 | S: BuildHasher + Default |
| 636 | { |
| 637 | fn from_iter<T: IntoIterator<Item=(K::Strong, V)>>(iter: T) -> Self { |
| 638 | let mut result = WeakKeyHashMap::with_hasher(Default::default()); |
| 639 | result.extend(iter); |
| 640 | result |
| 641 | } |
| 642 | } |
| 643 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 644 | impl<K, V, S> iter::Extend<(K::Strong, V)> for WeakKeyHashMap<K, V, S> |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 645 | where K: WeakKey, |
| 646 | S: BuildHasher |
| 647 | { |
| 648 | fn extend<T: IntoIterator<Item=(K::Strong, V)>>(&mut self, iter: T) { |
| 649 | for (key, value) in iter { |
| 650 | self.insert(key, value); |
| 651 | } |
| 652 | } |
| 653 | } |
| 654 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 655 | impl<'a, K, V, S> iter::Extend<(&'a K::Strong, &'a V)> for WeakKeyHashMap<K, V, S> |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 656 | where K: 'a + WeakKey, |
| 657 | K::Strong: Clone, |
| 658 | V: 'a + Clone, |
| 659 | S: BuildHasher |
| 660 | { |
| 661 | fn extend<T: IntoIterator<Item=(&'a K::Strong, &'a V)>>(&mut self, iter: T) { |
| 662 | for (key, value) in iter { |
| 663 | self.insert(key.clone(), value.clone()); |
| 664 | } |
| 665 | } |
| 666 | } |
| 667 | |
| 668 | enum BucketStatus { |
| 669 | Unoccupied, |
| 670 | MatchesKey, |
| 671 | ProbeDistance(usize), |
| 672 | } |
| 673 | |
| 674 | impl<'a, K: WeakKey, V> InnerEntry<'a, K, V> { |
| 675 | // Gets the status of the current bucket. |
| 676 | fn bucket_status(&self) -> BucketStatus { |
| 677 | match &self.map.buckets[self.pos] { |
| 678 | Some(bucket) => { |
| 679 | if bucket.2 == self.hash_code { |
| 680 | if let Some(key) = bucket.0.view() { |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 681 | if K::with_key(&self.key, |k| K::equals(&key, k)) { |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 682 | return BucketStatus::MatchesKey; |
| 683 | } |
| 684 | } |
| 685 | } |
| 686 | |
| 687 | let dist = self.probe_distance(self.pos, |
| 688 | self.which_bucket(bucket.2)); |
| 689 | BucketStatus::ProbeDistance(dist) |
| 690 | }, |
| 691 | None => BucketStatus::Unoccupied, |
| 692 | } |
| 693 | } |
| 694 | } |
| 695 | |
| 696 | impl<'a, K: WeakKey, V> Entry<'a, K, V> { |
| 697 | /// Ensures a value is in the entry by inserting a default value |
| 698 | /// if empty, and returns a mutable reference to the value in the |
| 699 | /// entry. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 700 | /// |
| 701 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 702 | pub fn or_insert(self, default: V) -> &'a mut V { |
| 703 | self.or_insert_with(|| default) |
| 704 | } |
| 705 | |
| 706 | /// Ensures a value is in the entry by inserting the result of the |
| 707 | /// default function if empty, and returns a mutable reference to |
| 708 | /// the value in the entry. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 709 | /// |
| 710 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 711 | pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V { |
| 712 | match self { |
| 713 | Entry::Occupied(occupied) => occupied.into_mut(), |
| 714 | Entry::Vacant(vacant) => vacant.insert(default()), |
| 715 | } |
| 716 | } |
| 717 | |
| 718 | /// Returns a reference to this entry's key. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 719 | /// |
| 720 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 721 | pub fn key(&self) -> &K::Strong { |
| 722 | match *self { |
| 723 | Entry::Occupied(ref occupied) => occupied.key(), |
| 724 | Entry::Vacant(ref vacant) => vacant.key(), |
| 725 | } |
| 726 | } |
| 727 | } |
| 728 | |
| 729 | impl<'a, K: WeakKey, V> OccupiedEntry<'a, K, V> { |
| 730 | /// Gets a reference to the key held by the entry. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 731 | /// |
| 732 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 733 | pub fn key(&self) -> &K::Strong { |
| 734 | &self.0.key |
| 735 | } |
| 736 | |
| 737 | /// Takes ownership of the key and value from the map. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 738 | /// |
| 739 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 740 | pub fn remove_entry(self) -> (K::Strong, V) { |
| 741 | let (_, value, _) = self.0.map.buckets[self.0.pos].take().unwrap(); |
| 742 | self.0.map.remove_index(self.0.pos); |
| 743 | (self.0.key, value) |
| 744 | } |
| 745 | |
| 746 | /// Gets a reference to the value in the entry. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 747 | /// |
| 748 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 749 | pub fn get(&self) -> &V { |
| 750 | &self.0.map.buckets[self.0.pos].as_ref().unwrap().1 |
| 751 | } |
| 752 | |
| 753 | /// Gets a mutable reference to the value in the entry. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 754 | /// |
| 755 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 756 | pub fn get_mut(&mut self) -> &mut V { |
| 757 | &mut self.0.map.buckets[self.0.pos].as_mut().unwrap().1 |
| 758 | } |
| 759 | |
| 760 | /// Turns the entry into a mutable reference to the value borrowed from the map. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 761 | /// |
| 762 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 763 | pub fn into_mut(self) -> &'a mut V { |
| 764 | &mut self.0.map.buckets[self.0.pos].as_mut().unwrap().1 |
| 765 | } |
| 766 | |
| 767 | /// Replaces the value in the entry with the given value. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 768 | /// |
| 769 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 770 | pub fn insert(&mut self, mut value: V) -> V { |
| 771 | self.0.map.buckets[self.0.pos].as_mut().unwrap().0 = K::new(&self.0.key); |
| 772 | mem::swap(self.get_mut(), &mut value); |
| 773 | value |
| 774 | } |
| 775 | |
| 776 | /// Removes the entry, returning the value. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 777 | /// |
| 778 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 779 | pub fn remove(self) -> V { |
| 780 | self.remove_entry().1 |
| 781 | } |
| 782 | } |
| 783 | |
| 784 | impl<'a, K: WeakKey, V> VacantEntry<'a, K, V> { |
| 785 | /// Gets a reference to the key that would be used when inserting a |
| 786 | /// value through the `VacantEntry`. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 787 | /// |
| 788 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 789 | pub fn key(&self) -> &K::Strong { |
| 790 | &self.0.key |
| 791 | } |
| 792 | |
| 793 | /// Returns ownership of the key. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 794 | /// |
| 795 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 796 | pub fn into_key(self) -> K::Strong { |
| 797 | self.0.key |
| 798 | } |
| 799 | |
| 800 | /// Inserts the key and value into the map and return a mutable |
| 801 | /// reference to the value. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 802 | /// |
| 803 | /// expected *O*(1) time; worst-case *O*(*p*) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 804 | pub fn insert(self, value: V) -> &'a mut V { |
| 805 | let old_bucket = mem::replace( |
| 806 | &mut self.0.map.buckets[self.0.pos], |
| 807 | Some((K::new(&self.0.key), value, self.0.hash_code))); |
| 808 | |
| 809 | if let Some(full_bucket) = old_bucket { |
| 810 | let next_bucket = self.next_bucket(self.0.pos); |
| 811 | self.0.map.steal(next_bucket, full_bucket); |
| 812 | } |
| 813 | |
| 814 | self.0.map.len += 1; |
| 815 | |
| 816 | &mut self.0.map.buckets[self.0.pos].as_mut().unwrap().1 |
| 817 | } |
| 818 | } |
| 819 | |
| 820 | impl<K: WeakKey, V> WeakKeyInnerMap<K, V> { |
| 821 | // Steals buckets starting at `pos`, replacing them with `bucket`. |
| 822 | fn steal(&mut self, mut pos: usize, mut bucket: FullBucket<K, V>) { |
| 823 | let mut my_dist = self.probe_distance(pos, self.which_bucket(bucket.2)); |
| 824 | |
| 825 | while let Some(hash_code) = self.buckets[pos].as_ref().and_then( |
| 826 | |bucket| if bucket.0.is_expired() {None} else {Some(bucket.2)}) { |
| 827 | |
| 828 | let victim_dist = self.probe_distance(pos, self.which_bucket(hash_code)); |
| 829 | |
| 830 | if my_dist > victim_dist { |
| 831 | mem::swap(self.buckets[pos].as_mut().unwrap(), &mut bucket); |
| 832 | my_dist = victim_dist; |
| 833 | } |
| 834 | |
| 835 | pos = self.next_bucket(pos); |
| 836 | my_dist += 1; |
| 837 | } |
| 838 | |
| 839 | self.buckets[pos] = Some(bucket); |
| 840 | } |
| 841 | |
| 842 | /// Removes the element at `dst`, shifting if necessary to preserve invariants. |
| 843 | fn remove_index(&mut self, mut dst: usize) { |
| 844 | let mut src = self.next_bucket(dst); |
| 845 | |
| 846 | // We are going to remove the buckets in the range [dst, src) |
| 847 | |
| 848 | loop { |
| 849 | let hash_code_option = self.buckets[src].as_ref().map(|tup| tup.2); |
| 850 | |
| 851 | if let Some(hash_code) = hash_code_option { |
| 852 | let goal_pos = self.which_bucket(hash_code); |
| 853 | let dist = self.probe_distance(src, goal_pos); |
| 854 | if dist == 0 { break; } |
| 855 | |
| 856 | if !self.buckets[src].as_ref().unwrap().0.is_expired() { |
| 857 | if in_interval(dst, goal_pos, src) { |
| 858 | self.erase_range(dst, goal_pos); |
| 859 | self.buckets[goal_pos] = self.buckets[src].take(); |
| 860 | dst = self.next_bucket(goal_pos); |
| 861 | } else { |
| 862 | self.buckets[dst] = self.buckets[src].take(); |
| 863 | dst = self.next_bucket(dst); |
| 864 | } |
| 865 | } |
| 866 | } else { |
| 867 | break; |
| 868 | } |
| 869 | |
| 870 | src = self.next_bucket(src); |
| 871 | } |
| 872 | |
| 873 | self.erase_range(dst, src); |
| 874 | } |
| 875 | |
| 876 | /// Erases the (presumably expired, but not empty) elements in [start, limit). |
| 877 | fn erase_range(&mut self, mut start: usize, limit: usize) |
| 878 | { |
| 879 | while start != limit { |
| 880 | self.buckets[start] = None; |
| 881 | self.len -= 1; |
| 882 | start = self.next_bucket(start); |
| 883 | } |
| 884 | } |
| 885 | } |
| 886 | |
| 887 | // Is value in [start, limit) modulo capacity? |
| 888 | fn in_interval(start: usize, value: usize, limit: usize) -> bool |
| 889 | { |
| 890 | if start <= limit { |
| 891 | start <= value && value < limit |
| 892 | } else { |
| 893 | start <= value || value < limit |
| 894 | } |
| 895 | } |
| 896 | |
| 897 | // Helper trait for computing with indices modulo capacity. |
| 898 | trait ModuloCapacity { |
| 899 | fn capacity(&self) -> usize; |
| 900 | |
| 901 | fn probe_distance(&self, actual: usize, ideal: usize) -> usize { |
| 902 | if actual >= ideal { |
| 903 | actual - ideal |
| 904 | } else { |
| 905 | actual + self.capacity() - ideal |
| 906 | } |
| 907 | } |
| 908 | |
| 909 | fn next_bucket(&self, pos: usize) -> usize { |
| 910 | assert_ne!( self.capacity(), 0 ); |
| 911 | (pos + 1) % self.capacity() |
| 912 | } |
| 913 | |
| 914 | fn which_bucket(&self, hash_code: HashCode) -> usize { |
| 915 | assert_ne!( self.capacity(), 0 ); |
| 916 | (hash_code.0 as usize) % self.capacity() |
| 917 | } |
| 918 | } |
| 919 | |
| 920 | impl<K, V> ModuloCapacity for WeakKeyInnerMap<K, V> { |
| 921 | fn capacity(&self) -> usize { |
| 922 | self.buckets.len() |
| 923 | } |
| 924 | } |
| 925 | |
| 926 | impl<K, V, S> ModuloCapacity for WeakKeyHashMap<K, V, S> { |
| 927 | fn capacity(&self) -> usize { |
| 928 | self.inner.capacity() |
| 929 | } |
| 930 | } |
| 931 | |
| 932 | impl<'a, K: WeakKey, V> ModuloCapacity for InnerEntry<'a, K, V> { |
| 933 | fn capacity(&self) -> usize { |
| 934 | self.map.capacity() |
| 935 | } |
| 936 | } |
| 937 | |
| 938 | impl<'a, K: WeakKey, V> ModuloCapacity for OccupiedEntry<'a, K, V> { |
| 939 | fn capacity(&self) -> usize { |
| 940 | self.0.capacity() |
| 941 | } |
| 942 | } |
| 943 | |
| 944 | impl<'a, K: WeakKey, V> ModuloCapacity for VacantEntry<'a, K, V> { |
| 945 | fn capacity(&self) -> usize { |
| 946 | self.0.capacity() |
| 947 | } |
| 948 | } |
| 949 | |
| 950 | impl<K, V> Debug for WeakKeyInnerMap<K, V> |
| 951 | where K: WeakElement, |
| 952 | K::Strong: Debug, |
| 953 | V: Debug |
| 954 | { |
| 955 | fn fmt(&self, f: &mut Formatter) -> fmt::Result { |
| 956 | write!(f, "{{ ")?; |
| 957 | for (i, bucket) in self.buckets.iter().enumerate() { |
| 958 | if let Some((ref k, ref v, _)) = *bucket { |
| 959 | write!(f, "[{}] {:?} => {:?}, ", i, k.view(), *v)?; |
| 960 | } |
| 961 | } |
| 962 | write!(f, "}}") |
| 963 | } |
| 964 | } |
| 965 | |
| 966 | impl<K: WeakElement, V: Debug, S> Debug for WeakKeyHashMap<K, V, S> |
| 967 | where K::Strong: Debug |
| 968 | { |
| 969 | fn fmt(&self, f: &mut Formatter) -> fmt::Result { |
| 970 | self.inner.fmt(f) |
| 971 | } |
| 972 | } |
| 973 | |
| 974 | impl<'a, K: WeakKey, V: Debug> Debug for Entry<'a, K, V> |
| 975 | where K::Strong: Debug |
| 976 | { |
| 977 | fn fmt(&self, f: &mut Formatter) -> fmt::Result { |
| 978 | match *self { |
| 979 | Entry::Occupied(ref e) => e.fmt(f), |
| 980 | Entry::Vacant(ref e) => e.fmt(f), |
| 981 | } |
| 982 | } |
| 983 | } |
| 984 | |
| 985 | impl<'a, K: WeakKey, V: Debug> Debug for OccupiedEntry<'a, K, V> |
| 986 | where K::Strong: Debug |
| 987 | { |
| 988 | fn fmt(&self, f: &mut Formatter) -> fmt::Result { |
| 989 | self.0.fmt(f) |
| 990 | } |
| 991 | } |
| 992 | |
| 993 | impl<'a, K: WeakKey, V: Debug> Debug for VacantEntry<'a, K, V> |
| 994 | where K::Strong: Debug |
| 995 | { |
| 996 | fn fmt(&self, f: &mut Formatter) -> fmt::Result { |
| 997 | self.0.fmt(f) |
| 998 | } |
| 999 | } |
| 1000 | |
| 1001 | impl<'a, K: WeakKey, V: Debug> Debug for InnerEntry<'a, K, V> |
| 1002 | where K::Strong: Debug |
| 1003 | { |
| 1004 | fn fmt(&self, f: &mut Formatter) -> fmt::Result { |
| 1005 | write!(f, "InnerEntry {{ pos = {}, buckets = {:?} }}", self.pos, self.map) |
| 1006 | } |
| 1007 | } |
| 1008 | |
| 1009 | impl<K: WeakElement, V, S> IntoIterator for WeakKeyHashMap<K, V, S> { |
| 1010 | type Item = (K::Strong, V); |
| 1011 | type IntoIter = IntoIter<K, V>; |
| 1012 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1013 | /// Creates an owning iterator from `self`. |
| 1014 | /// |
| 1015 | /// *O*(1) time (and *O*(*n*) time to dispose of the result) |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1016 | fn into_iter(self) -> Self::IntoIter { |
| 1017 | IntoIter { |
| 1018 | size: self.inner.len, |
| 1019 | base: self.inner.buckets.into_vec().into_iter(), |
| 1020 | } |
| 1021 | } |
| 1022 | } |
| 1023 | |
| 1024 | impl<'a, K: WeakElement, V, S> IntoIterator for &'a WeakKeyHashMap<K, V, S> { |
| 1025 | type Item = (K::Strong, &'a V); |
| 1026 | type IntoIter = Iter<'a, K, V>; |
| 1027 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1028 | /// Creates a borrowing iterator from `self`. |
| 1029 | /// |
| 1030 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1031 | fn into_iter(self) -> Self::IntoIter { |
| 1032 | Iter { |
| 1033 | base: self.inner.buckets.iter(), |
| 1034 | size: self.inner.len, |
| 1035 | } |
| 1036 | } |
| 1037 | } |
| 1038 | |
| 1039 | impl<'a, K: WeakElement, V, S> IntoIterator for &'a mut WeakKeyHashMap<K, V, S> { |
| 1040 | type Item = (K::Strong, &'a mut V); |
| 1041 | type IntoIter = IterMut<'a, K, V>; |
| 1042 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1043 | /// Creates a borrowing iterator from `self`. |
| 1044 | /// |
| 1045 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1046 | fn into_iter(self) -> Self::IntoIter { |
| 1047 | IterMut { |
| 1048 | base: self.inner.buckets.iter_mut(), |
| 1049 | size: self.inner.len, |
| 1050 | } |
| 1051 | } |
| 1052 | } |
| 1053 | |
| 1054 | impl<K: WeakElement, V, S> WeakKeyHashMap<K, V, S> { |
| 1055 | /// Gets an iterator over the keys and values. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1056 | /// |
| 1057 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1058 | pub fn iter(&self) -> Iter<K, V> { |
| 1059 | self.into_iter() |
| 1060 | } |
| 1061 | |
| 1062 | /// Gets an iterator over the keys. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1063 | /// |
| 1064 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1065 | pub fn keys(&self) -> Keys<K, V> { |
| 1066 | Keys(self.iter()) |
| 1067 | } |
| 1068 | |
| 1069 | /// Gets an iterator over the values. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1070 | /// |
| 1071 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1072 | pub fn values(&self) -> Values<K, V> { |
| 1073 | Values(self.iter()) |
| 1074 | } |
| 1075 | |
| 1076 | /// Gets an iterator over the keys and mutable values. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1077 | /// |
| 1078 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1079 | pub fn iter_mut(&mut self) -> IterMut<K, V> { |
| 1080 | self.into_iter() |
| 1081 | } |
| 1082 | |
| 1083 | /// Gets an iterator over the mutable values. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1084 | /// |
| 1085 | /// *O*(1) time |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1086 | pub fn values_mut(&mut self) -> ValuesMut<K, V> { |
| 1087 | ValuesMut(self.iter_mut()) |
| 1088 | } |
| 1089 | |
| 1090 | /// Gets a draining iterator, which removes all the values but retains the storage. |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1091 | /// |
| 1092 | /// *O*(1) time (and *O*(*n*) time to dispose of the result) |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1093 | pub fn drain(&mut self) -> Drain<K, V> { |
| 1094 | let old_len = self.inner.len; |
| 1095 | self.inner.len = 0; |
| 1096 | Drain { |
| 1097 | base: self.inner.buckets.iter_mut(), |
| 1098 | size: old_len, |
| 1099 | } |
| 1100 | } |
| 1101 | } |
| 1102 | |
| 1103 | #[cfg(test)] |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1104 | mod test { |
| 1105 | use crate::compat::{ |
| 1106 | eprintln, |
| 1107 | rc::{Rc, Weak}, |
| 1108 | String, |
| 1109 | Vec, |
| 1110 | }; |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1111 | use super::{Entry, WeakKeyHashMap}; |
| 1112 | |
| 1113 | #[test] |
| 1114 | fn simple() { |
| 1115 | let mut map: WeakKeyHashMap<Weak<str>, usize> = WeakKeyHashMap::new(); |
| 1116 | assert_eq!( map.len(), 0 ); |
| 1117 | assert!( !map.contains_key("five") ); |
| 1118 | |
David LeGare | 77e4bb9 | 2022-03-02 16:21:23 +0000 | [diff] [blame] | 1119 | let five: Rc<str> = Rc::from(String::from("five")); |
Joel Galenson | 2370d12 | 2020-10-12 16:02:26 -0700 | [diff] [blame] | 1120 | map.insert(five.clone(), 5); |
| 1121 | |
| 1122 | assert_eq!( map.len(), 1 ); |
| 1123 | assert!( map.contains_key("five") ); |
| 1124 | |
| 1125 | drop(five); |
| 1126 | |
| 1127 | assert_eq!( map.len(), 1 ); |
| 1128 | assert!( !map.contains_key("five") ); |
| 1129 | |
| 1130 | map.remove_expired(); |
| 1131 | |
| 1132 | assert_eq!( map.len(), 0 ); |
| 1133 | assert!( !map.contains_key("five") ); |
| 1134 | } |
| 1135 | |
| 1136 | // From https://github.com/tov/weak-table-rs/issues/1#issuecomment-461858060 |
| 1137 | #[test] |
| 1138 | fn insert_and_check() { |
| 1139 | let mut rcs: Vec<Rc<u32>> = Vec::new(); |
| 1140 | |
| 1141 | for i in 0 .. 50 { |
| 1142 | rcs.push(Rc::new(i)); |
| 1143 | } |
| 1144 | |
| 1145 | let mut weakmap: WeakKeyHashMap<Weak<u32>, f32> = WeakKeyHashMap::new(); |
| 1146 | |
| 1147 | for key in rcs.iter().cloned() { |
| 1148 | let f = *key as f32 + 0.1; |
| 1149 | weakmap.insert(key, f); |
| 1150 | } |
| 1151 | |
| 1152 | let mut count = 0; |
| 1153 | |
| 1154 | for key in &rcs { |
| 1155 | assert_eq!(weakmap.get(key), Some(&(**key as f32 + 0.1))); |
| 1156 | |
| 1157 | match weakmap.entry(Rc::clone(key)) { |
| 1158 | Entry::Occupied(_) => count += 1, |
| 1159 | Entry::Vacant(_) => eprintln!("WeakKeyHashMap: missing: {}", *key), |
| 1160 | } |
| 1161 | } |
| 1162 | |
| 1163 | assert_eq!( count, rcs.len() ); |
| 1164 | } |
| 1165 | } |