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1 | #[cfg(test)] | |
2 | mod tests; | |
3 | ||
4 | use hashbrown::hash_set as base; | |
5 | ||
6 | use crate::borrow::Borrow; | |
7 | use crate::collections::TryReserveError; | |
8 | use crate::fmt; | |
9 | use crate::hash::{BuildHasher, Hash}; | |
10 | use crate::iter::{Chain, FromIterator, FusedIterator}; | |
11 | use crate::ops::{BitAnd, BitOr, BitXor, Sub}; | |
12 | ||
13 | use super::map::{map_try_reserve_error, RandomState}; | |
14 | ||
15 | // Future Optimization (FIXME!) | |
16 | // ============================ | |
17 | // | |
18 | // Iteration over zero sized values is a noop. There is no need | |
19 | // for `bucket.val` in the case of HashSet. I suppose we would need HKT | |
20 | // to get rid of it properly. | |
21 | ||
22 | /// A [hash set] implemented as a `HashMap` where the value is `()`. | |
23 | /// | |
24 | /// As with the [`HashMap`] type, a `HashSet` requires that the elements | |
25 | /// implement the [`Eq`] and [`Hash`] traits. This can frequently be achieved by | |
26 | /// using `#[derive(PartialEq, Eq, Hash)]`. If you implement these yourself, | |
27 | /// it is important that the following property holds: | |
28 | /// | |
29 | /// ```text | |
30 | /// k1 == k2 -> hash(k1) == hash(k2) | |
31 | /// ``` | |
32 | /// | |
33 | /// In other words, if two keys are equal, their hashes must be equal. | |
34 | /// | |
35 | /// | |
36 | /// It is a logic error for an item to be modified in such a way that the | |
37 | /// item's hash, as determined by the [`Hash`] trait, or its equality, as | |
38 | /// determined by the [`Eq`] trait, changes while it is in the set. This is | |
39 | /// normally only possible through [`Cell`], [`RefCell`], global state, I/O, or | |
40 | /// unsafe code. The behavior resulting from such a logic error is not | |
41 | /// specified (it could include panics, incorrect results, aborts, memory | |
42 | /// leaks, or non-termination) but will not be undefined behavior. | |
43 | /// | |
44 | /// # Examples | |
45 | /// | |
46 | /// ``` | |
47 | /// use std::collections::HashSet; | |
48 | /// // Type inference lets us omit an explicit type signature (which | |
49 | /// // would be `HashSet<String>` in this example). | |
50 | /// let mut books = HashSet::new(); | |
51 | /// | |
52 | /// // Add some books. | |
53 | /// books.insert("A Dance With Dragons".to_string()); | |
54 | /// books.insert("To Kill a Mockingbird".to_string()); | |
55 | /// books.insert("The Odyssey".to_string()); | |
56 | /// books.insert("The Great Gatsby".to_string()); | |
57 | /// | |
58 | /// // Check for a specific one. | |
59 | /// if !books.contains("The Winds of Winter") { | |
60 | /// println!("We have {} books, but The Winds of Winter ain't one.", | |
61 | /// books.len()); | |
62 | /// } | |
63 | /// | |
64 | /// // Remove a book. | |
65 | /// books.remove("The Odyssey"); | |
66 | /// | |
67 | /// // Iterate over everything. | |
68 | /// for book in &books { | |
69 | /// println!("{}", book); | |
70 | /// } | |
71 | /// ``` | |
72 | /// | |
73 | /// The easiest way to use `HashSet` with a custom type is to derive | |
74 | /// [`Eq`] and [`Hash`]. We must also derive [`PartialEq`], this will in the | |
75 | /// future be implied by [`Eq`]. | |
76 | /// | |
77 | /// ``` | |
78 | /// use std::collections::HashSet; | |
79 | /// #[derive(Hash, Eq, PartialEq, Debug)] | |
80 | /// struct Viking { | |
81 | /// name: String, | |
82 | /// power: usize, | |
83 | /// } | |
84 | /// | |
85 | /// let mut vikings = HashSet::new(); | |
86 | /// | |
87 | /// vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); | |
88 | /// vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); | |
89 | /// vikings.insert(Viking { name: "Olaf".to_string(), power: 4 }); | |
90 | /// vikings.insert(Viking { name: "Harald".to_string(), power: 8 }); | |
91 | /// | |
92 | /// // Use derived implementation to print the vikings. | |
93 | /// for x in &vikings { | |
94 | /// println!("{:?}", x); | |
95 | /// } | |
96 | /// ``` | |
97 | /// | |
98 | /// A `HashSet` with a known list of items can be initialized from an array: | |
99 | /// | |
100 | /// ``` | |
101 | /// use std::collections::HashSet; | |
102 | /// | |
103 | /// let viking_names = HashSet::from(["Einar", "Olaf", "Harald"]); | |
104 | /// ``` | |
105 | /// | |
106 | /// [hash set]: crate::collections#use-the-set-variant-of-any-of-these-maps-when | |
107 | /// [`HashMap`]: crate::collections::HashMap | |
108 | /// [`RefCell`]: crate::cell::RefCell | |
109 | /// [`Cell`]: crate::cell::Cell | |
110 | #[cfg_attr(not(test), rustc_diagnostic_item = "HashSet")] | |
111 | #[stable(feature = "rust1", since = "1.0.0")] | |
112 | pub struct HashSet<T, S = RandomState> { | |
113 | base: base::HashSet<T, S>, | |
114 | } | |
115 | ||
116 | impl<T> HashSet<T, RandomState> { | |
117 | /// Creates an empty `HashSet`. | |
118 | /// | |
119 | /// The hash set is initially created with a capacity of 0, so it will not allocate until it | |
120 | /// is first inserted into. | |
121 | /// | |
122 | /// # Examples | |
123 | /// | |
124 | /// ``` | |
125 | /// use std::collections::HashSet; | |
126 | /// let set: HashSet<i32> = HashSet::new(); | |
127 | /// ``` | |
128 | #[inline] | |
129 | #[must_use] | |
130 | #[stable(feature = "rust1", since = "1.0.0")] | |
131 | pub fn new() -> HashSet<T, RandomState> { | |
132 | Default::default() | |
133 | } | |
134 | ||
135 | /// Creates an empty `HashSet` with the specified capacity. | |
136 | /// | |
137 | /// The hash set will be able to hold at least `capacity` elements without | |
138 | /// reallocating. If `capacity` is 0, the hash set will not allocate. | |
139 | /// | |
140 | /// # Examples | |
141 | /// | |
142 | /// ``` | |
143 | /// use std::collections::HashSet; | |
144 | /// let set: HashSet<i32> = HashSet::with_capacity(10); | |
145 | /// assert!(set.capacity() >= 10); | |
146 | /// ``` | |
147 | #[inline] | |
148 | #[must_use] | |
149 | #[stable(feature = "rust1", since = "1.0.0")] | |
150 | pub fn with_capacity(capacity: usize) -> HashSet<T, RandomState> { | |
151 | HashSet { base: base::HashSet::with_capacity_and_hasher(capacity, Default::default()) } | |
152 | } | |
153 | } | |
154 | ||
155 | impl<T, S> HashSet<T, S> { | |
156 | /// Returns the number of elements the set can hold without reallocating. | |
157 | /// | |
158 | /// # Examples | |
159 | /// | |
160 | /// ``` | |
161 | /// use std::collections::HashSet; | |
162 | /// let set: HashSet<i32> = HashSet::with_capacity(100); | |
163 | /// assert!(set.capacity() >= 100); | |
164 | /// ``` | |
165 | #[inline] | |
166 | #[stable(feature = "rust1", since = "1.0.0")] | |
167 | pub fn capacity(&self) -> usize { | |
168 | self.base.capacity() | |
169 | } | |
170 | ||
171 | /// An iterator visiting all elements in arbitrary order. | |
172 | /// The iterator element type is `&'a T`. | |
173 | /// | |
174 | /// # Examples | |
175 | /// | |
176 | /// ``` | |
177 | /// use std::collections::HashSet; | |
178 | /// let mut set = HashSet::new(); | |
179 | /// set.insert("a"); | |
180 | /// set.insert("b"); | |
181 | /// | |
182 | /// // Will print in an arbitrary order. | |
183 | /// for x in set.iter() { | |
184 | /// println!("{}", x); | |
185 | /// } | |
186 | /// ``` | |
187 | #[inline] | |
188 | #[stable(feature = "rust1", since = "1.0.0")] | |
189 | pub fn iter(&self) -> Iter<'_, T> { | |
190 | Iter { base: self.base.iter() } | |
191 | } | |
192 | ||
193 | /// Returns the number of elements in the set. | |
194 | /// | |
195 | /// # Examples | |
196 | /// | |
197 | /// ``` | |
198 | /// use std::collections::HashSet; | |
199 | /// | |
200 | /// let mut v = HashSet::new(); | |
201 | /// assert_eq!(v.len(), 0); | |
202 | /// v.insert(1); | |
203 | /// assert_eq!(v.len(), 1); | |
204 | /// ``` | |
205 | #[inline] | |
206 | #[stable(feature = "rust1", since = "1.0.0")] | |
207 | pub fn len(&self) -> usize { | |
208 | self.base.len() | |
209 | } | |
210 | ||
211 | /// Returns `true` if the set contains no elements. | |
212 | /// | |
213 | /// # Examples | |
214 | /// | |
215 | /// ``` | |
216 | /// use std::collections::HashSet; | |
217 | /// | |
218 | /// let mut v = HashSet::new(); | |
219 | /// assert!(v.is_empty()); | |
220 | /// v.insert(1); | |
221 | /// assert!(!v.is_empty()); | |
222 | /// ``` | |
223 | #[inline] | |
224 | #[stable(feature = "rust1", since = "1.0.0")] | |
225 | pub fn is_empty(&self) -> bool { | |
226 | self.base.is_empty() | |
227 | } | |
228 | ||
229 | /// Clears the set, returning all elements in an iterator. | |
230 | /// | |
231 | /// # Examples | |
232 | /// | |
233 | /// ``` | |
234 | /// use std::collections::HashSet; | |
235 | /// | |
236 | /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
237 | /// assert!(!set.is_empty()); | |
238 | /// | |
239 | /// // print 1, 2, 3 in an arbitrary order | |
240 | /// for i in set.drain() { | |
241 | /// println!("{}", i); | |
242 | /// } | |
243 | /// | |
244 | /// assert!(set.is_empty()); | |
245 | /// ``` | |
246 | #[inline] | |
247 | #[stable(feature = "drain", since = "1.6.0")] | |
248 | pub fn drain(&mut self) -> Drain<'_, T> { | |
249 | Drain { base: self.base.drain() } | |
250 | } | |
251 | ||
252 | /// Creates an iterator which uses a closure to determine if a value should be removed. | |
253 | /// | |
254 | /// If the closure returns true, then the value is removed and yielded. | |
255 | /// If the closure returns false, the value will remain in the list and will not be yielded | |
256 | /// by the iterator. | |
257 | /// | |
258 | /// If the iterator is only partially consumed or not consumed at all, each of the remaining | |
259 | /// values will still be subjected to the closure and removed and dropped if it returns true. | |
260 | /// | |
261 | /// It is unspecified how many more values will be subjected to the closure | |
262 | /// if a panic occurs in the closure, or if a panic occurs while dropping a value, or if the | |
263 | /// `DrainFilter` itself is leaked. | |
264 | /// | |
265 | /// # Examples | |
266 | /// | |
267 | /// Splitting a set into even and odd values, reusing the original set: | |
268 | /// | |
269 | /// ``` | |
270 | /// #![feature(hash_drain_filter)] | |
271 | /// use std::collections::HashSet; | |
272 | /// | |
273 | /// let mut set: HashSet<i32> = (0..8).collect(); | |
274 | /// let drained: HashSet<i32> = set.drain_filter(|v| v % 2 == 0).collect(); | |
275 | /// | |
276 | /// let mut evens = drained.into_iter().collect::<Vec<_>>(); | |
277 | /// let mut odds = set.into_iter().collect::<Vec<_>>(); | |
278 | /// evens.sort(); | |
279 | /// odds.sort(); | |
280 | /// | |
281 | /// assert_eq!(evens, vec![0, 2, 4, 6]); | |
282 | /// assert_eq!(odds, vec![1, 3, 5, 7]); | |
283 | /// ``` | |
284 | #[inline] | |
285 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
286 | pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, T, F> | |
287 | where | |
288 | F: FnMut(&T) -> bool, | |
289 | { | |
290 | DrainFilter { base: self.base.drain_filter(pred) } | |
291 | } | |
292 | ||
293 | /// Clears the set, removing all values. | |
294 | /// | |
295 | /// # Examples | |
296 | /// | |
297 | /// ``` | |
298 | /// use std::collections::HashSet; | |
299 | /// | |
300 | /// let mut v = HashSet::new(); | |
301 | /// v.insert(1); | |
302 | /// v.clear(); | |
303 | /// assert!(v.is_empty()); | |
304 | /// ``` | |
305 | #[inline] | |
306 | #[stable(feature = "rust1", since = "1.0.0")] | |
307 | pub fn clear(&mut self) { | |
308 | self.base.clear() | |
309 | } | |
310 | ||
311 | /// Creates a new empty hash set which will use the given hasher to hash | |
312 | /// keys. | |
313 | /// | |
314 | /// The hash set is also created with the default initial capacity. | |
315 | /// | |
316 | /// Warning: `hasher` is normally randomly generated, and | |
317 | /// is designed to allow `HashSet`s to be resistant to attacks that | |
318 | /// cause many collisions and very poor performance. Setting it | |
319 | /// manually using this function can expose a DoS attack vector. | |
320 | /// | |
321 | /// The `hash_builder` passed should implement the [`BuildHasher`] trait for | |
322 | /// the HashMap to be useful, see its documentation for details. | |
323 | /// | |
324 | /// # Examples | |
325 | /// | |
326 | /// ``` | |
327 | /// use std::collections::HashSet; | |
328 | /// use std::collections::hash_map::RandomState; | |
329 | /// | |
330 | /// let s = RandomState::new(); | |
331 | /// let mut set = HashSet::with_hasher(s); | |
332 | /// set.insert(2); | |
333 | /// ``` | |
334 | #[inline] | |
335 | #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] | |
336 | pub fn with_hasher(hasher: S) -> HashSet<T, S> { | |
337 | HashSet { base: base::HashSet::with_hasher(hasher) } | |
338 | } | |
339 | ||
340 | /// Creates an empty `HashSet` with the specified capacity, using | |
341 | /// `hasher` to hash the keys. | |
342 | /// | |
343 | /// The hash set will be able to hold at least `capacity` elements without | |
344 | /// reallocating. If `capacity` is 0, the hash set will not allocate. | |
345 | /// | |
346 | /// Warning: `hasher` is normally randomly generated, and | |
347 | /// is designed to allow `HashSet`s to be resistant to attacks that | |
348 | /// cause many collisions and very poor performance. Setting it | |
349 | /// manually using this function can expose a DoS attack vector. | |
350 | /// | |
351 | /// The `hash_builder` passed should implement the [`BuildHasher`] trait for | |
352 | /// the HashMap to be useful, see its documentation for details. | |
353 | /// | |
354 | /// # Examples | |
355 | /// | |
356 | /// ``` | |
357 | /// use std::collections::HashSet; | |
358 | /// use std::collections::hash_map::RandomState; | |
359 | /// | |
360 | /// let s = RandomState::new(); | |
361 | /// let mut set = HashSet::with_capacity_and_hasher(10, s); | |
362 | /// set.insert(1); | |
363 | /// ``` | |
364 | #[inline] | |
365 | #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] | |
366 | pub fn with_capacity_and_hasher(capacity: usize, hasher: S) -> HashSet<T, S> { | |
367 | HashSet { base: base::HashSet::with_capacity_and_hasher(capacity, hasher) } | |
368 | } | |
369 | ||
370 | /// Returns a reference to the set's [`BuildHasher`]. | |
371 | /// | |
372 | /// # Examples | |
373 | /// | |
374 | /// ``` | |
375 | /// use std::collections::HashSet; | |
376 | /// use std::collections::hash_map::RandomState; | |
377 | /// | |
378 | /// let hasher = RandomState::new(); | |
379 | /// let set: HashSet<i32> = HashSet::with_hasher(hasher); | |
380 | /// let hasher: &RandomState = set.hasher(); | |
381 | /// ``` | |
382 | #[inline] | |
383 | #[stable(feature = "hashmap_public_hasher", since = "1.9.0")] | |
384 | pub fn hasher(&self) -> &S { | |
385 | self.base.hasher() | |
386 | } | |
387 | } | |
388 | ||
389 | impl<T, S> HashSet<T, S> | |
390 | where | |
391 | T: Eq + Hash, | |
392 | S: BuildHasher, | |
393 | { | |
394 | /// Reserves capacity for at least `additional` more elements to be inserted | |
395 | /// in the `HashSet`. The collection may reserve more space to avoid | |
396 | /// frequent reallocations. | |
397 | /// | |
398 | /// # Panics | |
399 | /// | |
400 | /// Panics if the new allocation size overflows `usize`. | |
401 | /// | |
402 | /// # Examples | |
403 | /// | |
404 | /// ``` | |
405 | /// use std::collections::HashSet; | |
406 | /// let mut set: HashSet<i32> = HashSet::new(); | |
407 | /// set.reserve(10); | |
408 | /// assert!(set.capacity() >= 10); | |
409 | /// ``` | |
410 | #[inline] | |
411 | #[stable(feature = "rust1", since = "1.0.0")] | |
412 | pub fn reserve(&mut self, additional: usize) { | |
413 | self.base.reserve(additional) | |
414 | } | |
415 | ||
416 | /// Tries to reserve capacity for at least `additional` more elements to be inserted | |
417 | /// in the given `HashSet<K, V>`. The collection may reserve more space to avoid | |
418 | /// frequent reallocations. | |
419 | /// | |
420 | /// # Errors | |
421 | /// | |
422 | /// If the capacity overflows, or the allocator reports a failure, then an error | |
423 | /// is returned. | |
424 | /// | |
425 | /// # Examples | |
426 | /// | |
427 | /// ``` | |
428 | /// use std::collections::HashSet; | |
429 | /// let mut set: HashSet<i32> = HashSet::new(); | |
430 | /// set.try_reserve(10).expect("why is the test harness OOMing on 10 bytes?"); | |
431 | /// ``` | |
432 | #[inline] | |
433 | #[stable(feature = "try_reserve", since = "1.57.0")] | |
434 | pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> { | |
435 | self.base.try_reserve(additional).map_err(map_try_reserve_error) | |
436 | } | |
437 | ||
438 | /// Shrinks the capacity of the set as much as possible. It will drop | |
439 | /// down as much as possible while maintaining the internal rules | |
440 | /// and possibly leaving some space in accordance with the resize policy. | |
441 | /// | |
442 | /// # Examples | |
443 | /// | |
444 | /// ``` | |
445 | /// use std::collections::HashSet; | |
446 | /// | |
447 | /// let mut set = HashSet::with_capacity(100); | |
448 | /// set.insert(1); | |
449 | /// set.insert(2); | |
450 | /// assert!(set.capacity() >= 100); | |
451 | /// set.shrink_to_fit(); | |
452 | /// assert!(set.capacity() >= 2); | |
453 | /// ``` | |
454 | #[inline] | |
455 | #[stable(feature = "rust1", since = "1.0.0")] | |
456 | pub fn shrink_to_fit(&mut self) { | |
457 | self.base.shrink_to_fit() | |
458 | } | |
459 | ||
460 | /// Shrinks the capacity of the set with a lower limit. It will drop | |
461 | /// down no lower than the supplied limit while maintaining the internal rules | |
462 | /// and possibly leaving some space in accordance with the resize policy. | |
463 | /// | |
464 | /// If the current capacity is less than the lower limit, this is a no-op. | |
465 | /// # Examples | |
466 | /// | |
467 | /// ``` | |
468 | /// use std::collections::HashSet; | |
469 | /// | |
470 | /// let mut set = HashSet::with_capacity(100); | |
471 | /// set.insert(1); | |
472 | /// set.insert(2); | |
473 | /// assert!(set.capacity() >= 100); | |
474 | /// set.shrink_to(10); | |
475 | /// assert!(set.capacity() >= 10); | |
476 | /// set.shrink_to(0); | |
477 | /// assert!(set.capacity() >= 2); | |
478 | /// ``` | |
479 | #[inline] | |
480 | #[stable(feature = "shrink_to", since = "1.56.0")] | |
481 | pub fn shrink_to(&mut self, min_capacity: usize) { | |
482 | self.base.shrink_to(min_capacity) | |
483 | } | |
484 | ||
485 | /// Visits the values representing the difference, | |
486 | /// i.e., the values that are in `self` but not in `other`. | |
487 | /// | |
488 | /// # Examples | |
489 | /// | |
490 | /// ``` | |
491 | /// use std::collections::HashSet; | |
492 | /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
493 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
494 | /// | |
495 | /// // Can be seen as `a - b`. | |
496 | /// for x in a.difference(&b) { | |
497 | /// println!("{}", x); // Print 1 | |
498 | /// } | |
499 | /// | |
500 | /// let diff: HashSet<_> = a.difference(&b).collect(); | |
501 | /// assert_eq!(diff, [1].iter().collect()); | |
502 | /// | |
503 | /// // Note that difference is not symmetric, | |
504 | /// // and `b - a` means something else: | |
505 | /// let diff: HashSet<_> = b.difference(&a).collect(); | |
506 | /// assert_eq!(diff, [4].iter().collect()); | |
507 | /// ``` | |
508 | #[inline] | |
509 | #[stable(feature = "rust1", since = "1.0.0")] | |
510 | pub fn difference<'a>(&'a self, other: &'a HashSet<T, S>) -> Difference<'a, T, S> { | |
511 | Difference { iter: self.iter(), other } | |
512 | } | |
513 | ||
514 | /// Visits the values representing the symmetric difference, | |
515 | /// i.e., the values that are in `self` or in `other` but not in both. | |
516 | /// | |
517 | /// # Examples | |
518 | /// | |
519 | /// ``` | |
520 | /// use std::collections::HashSet; | |
521 | /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
522 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
523 | /// | |
524 | /// // Print 1, 4 in arbitrary order. | |
525 | /// for x in a.symmetric_difference(&b) { | |
526 | /// println!("{}", x); | |
527 | /// } | |
528 | /// | |
529 | /// let diff1: HashSet<_> = a.symmetric_difference(&b).collect(); | |
530 | /// let diff2: HashSet<_> = b.symmetric_difference(&a).collect(); | |
531 | /// | |
532 | /// assert_eq!(diff1, diff2); | |
533 | /// assert_eq!(diff1, [1, 4].iter().collect()); | |
534 | /// ``` | |
535 | #[inline] | |
536 | #[stable(feature = "rust1", since = "1.0.0")] | |
537 | pub fn symmetric_difference<'a>( | |
538 | &'a self, | |
539 | other: &'a HashSet<T, S>, | |
540 | ) -> SymmetricDifference<'a, T, S> { | |
541 | SymmetricDifference { iter: self.difference(other).chain(other.difference(self)) } | |
542 | } | |
543 | ||
544 | /// Visits the values representing the intersection, | |
545 | /// i.e., the values that are both in `self` and `other`. | |
546 | /// | |
547 | /// # Examples | |
548 | /// | |
549 | /// ``` | |
550 | /// use std::collections::HashSet; | |
551 | /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
552 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
553 | /// | |
554 | /// // Print 2, 3 in arbitrary order. | |
555 | /// for x in a.intersection(&b) { | |
556 | /// println!("{}", x); | |
557 | /// } | |
558 | /// | |
559 | /// let intersection: HashSet<_> = a.intersection(&b).collect(); | |
560 | /// assert_eq!(intersection, [2, 3].iter().collect()); | |
561 | /// ``` | |
562 | #[inline] | |
563 | #[stable(feature = "rust1", since = "1.0.0")] | |
564 | pub fn intersection<'a>(&'a self, other: &'a HashSet<T, S>) -> Intersection<'a, T, S> { | |
565 | if self.len() <= other.len() { | |
566 | Intersection { iter: self.iter(), other } | |
567 | } else { | |
568 | Intersection { iter: other.iter(), other: self } | |
569 | } | |
570 | } | |
571 | ||
572 | /// Visits the values representing the union, | |
573 | /// i.e., all the values in `self` or `other`, without duplicates. | |
574 | /// | |
575 | /// # Examples | |
576 | /// | |
577 | /// ``` | |
578 | /// use std::collections::HashSet; | |
579 | /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
580 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
581 | /// | |
582 | /// // Print 1, 2, 3, 4 in arbitrary order. | |
583 | /// for x in a.union(&b) { | |
584 | /// println!("{}", x); | |
585 | /// } | |
586 | /// | |
587 | /// let union: HashSet<_> = a.union(&b).collect(); | |
588 | /// assert_eq!(union, [1, 2, 3, 4].iter().collect()); | |
589 | /// ``` | |
590 | #[inline] | |
591 | #[stable(feature = "rust1", since = "1.0.0")] | |
592 | pub fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S> { | |
593 | if self.len() >= other.len() { | |
594 | Union { iter: self.iter().chain(other.difference(self)) } | |
595 | } else { | |
596 | Union { iter: other.iter().chain(self.difference(other)) } | |
597 | } | |
598 | } | |
599 | ||
600 | /// Returns `true` if the set contains a value. | |
601 | /// | |
602 | /// The value may be any borrowed form of the set's value type, but | |
603 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for | |
604 | /// the value type. | |
605 | /// | |
606 | /// # Examples | |
607 | /// | |
608 | /// ``` | |
609 | /// use std::collections::HashSet; | |
610 | /// | |
611 | /// let set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
612 | /// assert_eq!(set.contains(&1), true); | |
613 | /// assert_eq!(set.contains(&4), false); | |
614 | /// ``` | |
615 | #[inline] | |
616 | #[stable(feature = "rust1", since = "1.0.0")] | |
617 | pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool | |
618 | where | |
619 | T: Borrow<Q>, | |
620 | Q: Hash + Eq, | |
621 | { | |
622 | self.base.contains(value) | |
623 | } | |
624 | ||
625 | /// Returns a reference to the value in the set, if any, that is equal to the given value. | |
626 | /// | |
627 | /// The value may be any borrowed form of the set's value type, but | |
628 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for | |
629 | /// the value type. | |
630 | /// | |
631 | /// # Examples | |
632 | /// | |
633 | /// ``` | |
634 | /// use std::collections::HashSet; | |
635 | /// | |
636 | /// let set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
637 | /// assert_eq!(set.get(&2), Some(&2)); | |
638 | /// assert_eq!(set.get(&4), None); | |
639 | /// ``` | |
640 | #[inline] | |
641 | #[stable(feature = "set_recovery", since = "1.9.0")] | |
642 | pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T> | |
643 | where | |
644 | T: Borrow<Q>, | |
645 | Q: Hash + Eq, | |
646 | { | |
647 | self.base.get(value) | |
648 | } | |
649 | ||
650 | /// Inserts the given `value` into the set if it is not present, then | |
651 | /// returns a reference to the value in the set. | |
652 | /// | |
653 | /// # Examples | |
654 | /// | |
655 | /// ``` | |
656 | /// #![feature(hash_set_entry)] | |
657 | /// | |
658 | /// use std::collections::HashSet; | |
659 | /// | |
660 | /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
661 | /// assert_eq!(set.len(), 3); | |
662 | /// assert_eq!(set.get_or_insert(2), &2); | |
663 | /// assert_eq!(set.get_or_insert(100), &100); | |
664 | /// assert_eq!(set.len(), 4); // 100 was inserted | |
665 | /// ``` | |
666 | #[inline] | |
667 | #[unstable(feature = "hash_set_entry", issue = "60896")] | |
668 | pub fn get_or_insert(&mut self, value: T) -> &T { | |
669 | // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with | |
670 | // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`. | |
671 | self.base.get_or_insert(value) | |
672 | } | |
673 | ||
674 | /// Inserts an owned copy of the given `value` into the set if it is not | |
675 | /// present, then returns a reference to the value in the set. | |
676 | /// | |
677 | /// # Examples | |
678 | /// | |
679 | /// ``` | |
680 | /// #![feature(hash_set_entry)] | |
681 | /// | |
682 | /// use std::collections::HashSet; | |
683 | /// | |
684 | /// let mut set: HashSet<String> = ["cat", "dog", "horse"] | |
685 | /// .iter().map(|&pet| pet.to_owned()).collect(); | |
686 | /// | |
687 | /// assert_eq!(set.len(), 3); | |
688 | /// for &pet in &["cat", "dog", "fish"] { | |
689 | /// let value = set.get_or_insert_owned(pet); | |
690 | /// assert_eq!(value, pet); | |
691 | /// } | |
692 | /// assert_eq!(set.len(), 4); // a new "fish" was inserted | |
693 | /// ``` | |
694 | #[inline] | |
695 | #[unstable(feature = "hash_set_entry", issue = "60896")] | |
696 | pub fn get_or_insert_owned<Q: ?Sized>(&mut self, value: &Q) -> &T | |
697 | where | |
698 | T: Borrow<Q>, | |
699 | Q: Hash + Eq + ToOwned<Owned = T>, | |
700 | { | |
701 | // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with | |
702 | // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`. | |
703 | self.base.get_or_insert_owned(value) | |
704 | } | |
705 | ||
706 | /// Inserts a value computed from `f` into the set if the given `value` is | |
707 | /// not present, then returns a reference to the value in the set. | |
708 | /// | |
709 | /// # Examples | |
710 | /// | |
711 | /// ``` | |
712 | /// #![feature(hash_set_entry)] | |
713 | /// | |
714 | /// use std::collections::HashSet; | |
715 | /// | |
716 | /// let mut set: HashSet<String> = ["cat", "dog", "horse"] | |
717 | /// .iter().map(|&pet| pet.to_owned()).collect(); | |
718 | /// | |
719 | /// assert_eq!(set.len(), 3); | |
720 | /// for &pet in &["cat", "dog", "fish"] { | |
721 | /// let value = set.get_or_insert_with(pet, str::to_owned); | |
722 | /// assert_eq!(value, pet); | |
723 | /// } | |
724 | /// assert_eq!(set.len(), 4); // a new "fish" was inserted | |
725 | /// ``` | |
726 | #[inline] | |
727 | #[unstable(feature = "hash_set_entry", issue = "60896")] | |
728 | pub fn get_or_insert_with<Q: ?Sized, F>(&mut self, value: &Q, f: F) -> &T | |
729 | where | |
730 | T: Borrow<Q>, | |
731 | Q: Hash + Eq, | |
732 | F: FnOnce(&Q) -> T, | |
733 | { | |
734 | // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with | |
735 | // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`. | |
736 | self.base.get_or_insert_with(value, f) | |
737 | } | |
738 | ||
739 | /// Returns `true` if `self` has no elements in common with `other`. | |
740 | /// This is equivalent to checking for an empty intersection. | |
741 | /// | |
742 | /// # Examples | |
743 | /// | |
744 | /// ``` | |
745 | /// use std::collections::HashSet; | |
746 | /// | |
747 | /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
748 | /// let mut b = HashSet::new(); | |
749 | /// | |
750 | /// assert_eq!(a.is_disjoint(&b), true); | |
751 | /// b.insert(4); | |
752 | /// assert_eq!(a.is_disjoint(&b), true); | |
753 | /// b.insert(1); | |
754 | /// assert_eq!(a.is_disjoint(&b), false); | |
755 | /// ``` | |
756 | #[stable(feature = "rust1", since = "1.0.0")] | |
757 | pub fn is_disjoint(&self, other: &HashSet<T, S>) -> bool { | |
758 | if self.len() <= other.len() { | |
759 | self.iter().all(|v| !other.contains(v)) | |
760 | } else { | |
761 | other.iter().all(|v| !self.contains(v)) | |
762 | } | |
763 | } | |
764 | ||
765 | /// Returns `true` if the set is a subset of another, | |
766 | /// i.e., `other` contains at least all the values in `self`. | |
767 | /// | |
768 | /// # Examples | |
769 | /// | |
770 | /// ``` | |
771 | /// use std::collections::HashSet; | |
772 | /// | |
773 | /// let sup: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
774 | /// let mut set = HashSet::new(); | |
775 | /// | |
776 | /// assert_eq!(set.is_subset(&sup), true); | |
777 | /// set.insert(2); | |
778 | /// assert_eq!(set.is_subset(&sup), true); | |
779 | /// set.insert(4); | |
780 | /// assert_eq!(set.is_subset(&sup), false); | |
781 | /// ``` | |
782 | #[stable(feature = "rust1", since = "1.0.0")] | |
783 | pub fn is_subset(&self, other: &HashSet<T, S>) -> bool { | |
784 | if self.len() <= other.len() { self.iter().all(|v| other.contains(v)) } else { false } | |
785 | } | |
786 | ||
787 | /// Returns `true` if the set is a superset of another, | |
788 | /// i.e., `self` contains at least all the values in `other`. | |
789 | /// | |
790 | /// # Examples | |
791 | /// | |
792 | /// ``` | |
793 | /// use std::collections::HashSet; | |
794 | /// | |
795 | /// let sub: HashSet<_> = [1, 2].iter().cloned().collect(); | |
796 | /// let mut set = HashSet::new(); | |
797 | /// | |
798 | /// assert_eq!(set.is_superset(&sub), false); | |
799 | /// | |
800 | /// set.insert(0); | |
801 | /// set.insert(1); | |
802 | /// assert_eq!(set.is_superset(&sub), false); | |
803 | /// | |
804 | /// set.insert(2); | |
805 | /// assert_eq!(set.is_superset(&sub), true); | |
806 | /// ``` | |
807 | #[inline] | |
808 | #[stable(feature = "rust1", since = "1.0.0")] | |
809 | pub fn is_superset(&self, other: &HashSet<T, S>) -> bool { | |
810 | other.is_subset(self) | |
811 | } | |
812 | ||
813 | /// Adds a value to the set. | |
814 | /// | |
815 | /// If the set did not have this value present, `true` is returned. | |
816 | /// | |
817 | /// If the set did have this value present, `false` is returned. | |
818 | /// | |
819 | /// # Examples | |
820 | /// | |
821 | /// ``` | |
822 | /// use std::collections::HashSet; | |
823 | /// | |
824 | /// let mut set = HashSet::new(); | |
825 | /// | |
826 | /// assert_eq!(set.insert(2), true); | |
827 | /// assert_eq!(set.insert(2), false); | |
828 | /// assert_eq!(set.len(), 1); | |
829 | /// ``` | |
830 | #[inline] | |
831 | #[stable(feature = "rust1", since = "1.0.0")] | |
832 | pub fn insert(&mut self, value: T) -> bool { | |
833 | self.base.insert(value) | |
834 | } | |
835 | ||
836 | /// Adds a value to the set, replacing the existing value, if any, that is equal to the given | |
837 | /// one. Returns the replaced value. | |
838 | /// | |
839 | /// # Examples | |
840 | /// | |
841 | /// ``` | |
842 | /// use std::collections::HashSet; | |
843 | /// | |
844 | /// let mut set = HashSet::new(); | |
845 | /// set.insert(Vec::<i32>::new()); | |
846 | /// | |
847 | /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 0); | |
848 | /// set.replace(Vec::with_capacity(10)); | |
849 | /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 10); | |
850 | /// ``` | |
851 | #[inline] | |
852 | #[stable(feature = "set_recovery", since = "1.9.0")] | |
853 | pub fn replace(&mut self, value: T) -> Option<T> { | |
854 | self.base.replace(value) | |
855 | } | |
856 | ||
857 | /// Removes a value from the set. Returns whether the value was | |
858 | /// present in the set. | |
859 | /// | |
860 | /// The value may be any borrowed form of the set's value type, but | |
861 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for | |
862 | /// the value type. | |
863 | /// | |
864 | /// # Examples | |
865 | /// | |
866 | /// ``` | |
867 | /// use std::collections::HashSet; | |
868 | /// | |
869 | /// let mut set = HashSet::new(); | |
870 | /// | |
871 | /// set.insert(2); | |
872 | /// assert_eq!(set.remove(&2), true); | |
873 | /// assert_eq!(set.remove(&2), false); | |
874 | /// ``` | |
875 | #[inline] | |
876 | #[stable(feature = "rust1", since = "1.0.0")] | |
877 | pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool | |
878 | where | |
879 | T: Borrow<Q>, | |
880 | Q: Hash + Eq, | |
881 | { | |
882 | self.base.remove(value) | |
883 | } | |
884 | ||
885 | /// Removes and returns the value in the set, if any, that is equal to the given one. | |
886 | /// | |
887 | /// The value may be any borrowed form of the set's value type, but | |
888 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for | |
889 | /// the value type. | |
890 | /// | |
891 | /// # Examples | |
892 | /// | |
893 | /// ``` | |
894 | /// use std::collections::HashSet; | |
895 | /// | |
896 | /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); | |
897 | /// assert_eq!(set.take(&2), Some(2)); | |
898 | /// assert_eq!(set.take(&2), None); | |
899 | /// ``` | |
900 | #[inline] | |
901 | #[stable(feature = "set_recovery", since = "1.9.0")] | |
902 | pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> | |
903 | where | |
904 | T: Borrow<Q>, | |
905 | Q: Hash + Eq, | |
906 | { | |
907 | self.base.take(value) | |
908 | } | |
909 | ||
910 | /// Retains only the elements specified by the predicate. | |
911 | /// | |
912 | /// In other words, remove all elements `e` such that `f(&e)` returns `false`. | |
913 | /// The elements are visited in unsorted (and unspecified) order. | |
914 | /// | |
915 | /// # Examples | |
916 | /// | |
917 | /// ``` | |
918 | /// use std::collections::HashSet; | |
919 | /// | |
920 | /// let xs = [1, 2, 3, 4, 5, 6]; | |
921 | /// let mut set: HashSet<i32> = xs.iter().cloned().collect(); | |
922 | /// set.retain(|&k| k % 2 == 0); | |
923 | /// assert_eq!(set.len(), 3); | |
924 | /// ``` | |
925 | #[stable(feature = "retain_hash_collection", since = "1.18.0")] | |
926 | pub fn retain<F>(&mut self, f: F) | |
927 | where | |
928 | F: FnMut(&T) -> bool, | |
929 | { | |
930 | self.base.retain(f) | |
931 | } | |
932 | } | |
933 | ||
934 | #[stable(feature = "rust1", since = "1.0.0")] | |
935 | impl<T, S> Clone for HashSet<T, S> | |
936 | where | |
937 | T: Clone, | |
938 | S: Clone, | |
939 | { | |
940 | #[inline] | |
941 | fn clone(&self) -> Self { | |
942 | Self { base: self.base.clone() } | |
943 | } | |
944 | ||
945 | #[inline] | |
946 | fn clone_from(&mut self, other: &Self) { | |
947 | self.base.clone_from(&other.base); | |
948 | } | |
949 | } | |
950 | ||
951 | #[stable(feature = "rust1", since = "1.0.0")] | |
952 | impl<T, S> PartialEq for HashSet<T, S> | |
953 | where | |
954 | T: Eq + Hash, | |
955 | S: BuildHasher, | |
956 | { | |
957 | fn eq(&self, other: &HashSet<T, S>) -> bool { | |
958 | if self.len() != other.len() { | |
959 | return false; | |
960 | } | |
961 | ||
962 | self.iter().all(|key| other.contains(key)) | |
963 | } | |
964 | } | |
965 | ||
966 | #[stable(feature = "rust1", since = "1.0.0")] | |
967 | impl<T, S> Eq for HashSet<T, S> | |
968 | where | |
969 | T: Eq + Hash, | |
970 | S: BuildHasher, | |
971 | { | |
972 | } | |
973 | ||
974 | #[stable(feature = "rust1", since = "1.0.0")] | |
975 | impl<T, S> fmt::Debug for HashSet<T, S> | |
976 | where | |
977 | T: fmt::Debug, | |
978 | { | |
979 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
980 | f.debug_set().entries(self.iter()).finish() | |
981 | } | |
982 | } | |
983 | ||
984 | #[stable(feature = "rust1", since = "1.0.0")] | |
985 | impl<T, S> FromIterator<T> for HashSet<T, S> | |
986 | where | |
987 | T: Eq + Hash, | |
988 | S: BuildHasher + Default, | |
989 | { | |
990 | #[inline] | |
991 | fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> HashSet<T, S> { | |
992 | let mut set = HashSet::with_hasher(Default::default()); | |
993 | set.extend(iter); | |
994 | set | |
995 | } | |
996 | } | |
997 | ||
998 | #[stable(feature = "std_collections_from_array", since = "1.56.0")] | |
999 | // Note: as what is currently the most convenient built-in way to construct | |
1000 | // a HashSet, a simple usage of this function must not *require* the user | |
1001 | // to provide a type annotation in order to infer the third type parameter | |
1002 | // (the hasher parameter, conventionally "S"). | |
1003 | // To that end, this impl is defined using RandomState as the concrete | |
1004 | // type of S, rather than being generic over `S: BuildHasher + Default`. | |
1005 | // It is expected that users who want to specify a hasher will manually use | |
1006 | // `with_capacity_and_hasher`. | |
1007 | // If type parameter defaults worked on impls, and if type parameter | |
1008 | // defaults could be mixed with const generics, then perhaps | |
1009 | // this could be generalized. | |
1010 | // See also the equivalent impl on HashMap. | |
1011 | impl<T, const N: usize> From<[T; N]> for HashSet<T, RandomState> | |
1012 | where | |
1013 | T: Eq + Hash, | |
1014 | { | |
1015 | /// # Examples | |
1016 | /// | |
1017 | /// ``` | |
1018 | /// use std::collections::HashSet; | |
1019 | /// | |
1020 | /// let set1 = HashSet::from([1, 2, 3, 4]); | |
1021 | /// let set2: HashSet<_> = [1, 2, 3, 4].into(); | |
1022 | /// assert_eq!(set1, set2); | |
1023 | /// ``` | |
1024 | fn from(arr: [T; N]) -> Self { | |
1025 | crate::array::IntoIter::new(arr).collect() | |
1026 | } | |
1027 | } | |
1028 | ||
1029 | #[stable(feature = "rust1", since = "1.0.0")] | |
1030 | impl<T, S> Extend<T> for HashSet<T, S> | |
1031 | where | |
1032 | T: Eq + Hash, | |
1033 | S: BuildHasher, | |
1034 | { | |
1035 | #[inline] | |
1036 | fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { | |
1037 | self.base.extend(iter); | |
1038 | } | |
1039 | ||
1040 | #[inline] | |
1041 | fn extend_one(&mut self, item: T) { | |
1042 | self.base.insert(item); | |
1043 | } | |
1044 | ||
1045 | #[inline] | |
1046 | fn extend_reserve(&mut self, additional: usize) { | |
1047 | self.base.extend_reserve(additional); | |
1048 | } | |
1049 | } | |
1050 | ||
1051 | #[stable(feature = "hash_extend_copy", since = "1.4.0")] | |
1052 | impl<'a, T, S> Extend<&'a T> for HashSet<T, S> | |
1053 | where | |
1054 | T: 'a + Eq + Hash + Copy, | |
1055 | S: BuildHasher, | |
1056 | { | |
1057 | #[inline] | |
1058 | fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { | |
1059 | self.extend(iter.into_iter().cloned()); | |
1060 | } | |
1061 | ||
1062 | #[inline] | |
1063 | fn extend_one(&mut self, &item: &'a T) { | |
1064 | self.base.insert(item); | |
1065 | } | |
1066 | ||
1067 | #[inline] | |
1068 | fn extend_reserve(&mut self, additional: usize) { | |
1069 | Extend::<T>::extend_reserve(self, additional) | |
1070 | } | |
1071 | } | |
1072 | ||
1073 | #[stable(feature = "rust1", since = "1.0.0")] | |
1074 | impl<T, S> Default for HashSet<T, S> | |
1075 | where | |
1076 | S: Default, | |
1077 | { | |
1078 | /// Creates an empty `HashSet<T, S>` with the `Default` value for the hasher. | |
1079 | #[inline] | |
1080 | fn default() -> HashSet<T, S> { | |
1081 | HashSet { base: Default::default() } | |
1082 | } | |
1083 | } | |
1084 | ||
1085 | #[stable(feature = "rust1", since = "1.0.0")] | |
1086 | impl<T, S> BitOr<&HashSet<T, S>> for &HashSet<T, S> | |
1087 | where | |
1088 | T: Eq + Hash + Clone, | |
1089 | S: BuildHasher + Default, | |
1090 | { | |
1091 | type Output = HashSet<T, S>; | |
1092 | ||
1093 | /// Returns the union of `self` and `rhs` as a new `HashSet<T, S>`. | |
1094 | /// | |
1095 | /// # Examples | |
1096 | /// | |
1097 | /// ``` | |
1098 | /// use std::collections::HashSet; | |
1099 | /// | |
1100 | /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); | |
1101 | /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect(); | |
1102 | /// | |
1103 | /// let set = &a | &b; | |
1104 | /// | |
1105 | /// let mut i = 0; | |
1106 | /// let expected = [1, 2, 3, 4, 5]; | |
1107 | /// for x in &set { | |
1108 | /// assert!(expected.contains(x)); | |
1109 | /// i += 1; | |
1110 | /// } | |
1111 | /// assert_eq!(i, expected.len()); | |
1112 | /// ``` | |
1113 | fn bitor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1114 | self.union(rhs).cloned().collect() | |
1115 | } | |
1116 | } | |
1117 | ||
1118 | #[stable(feature = "rust1", since = "1.0.0")] | |
1119 | impl<T, S> BitAnd<&HashSet<T, S>> for &HashSet<T, S> | |
1120 | where | |
1121 | T: Eq + Hash + Clone, | |
1122 | S: BuildHasher + Default, | |
1123 | { | |
1124 | type Output = HashSet<T, S>; | |
1125 | ||
1126 | /// Returns the intersection of `self` and `rhs` as a new `HashSet<T, S>`. | |
1127 | /// | |
1128 | /// # Examples | |
1129 | /// | |
1130 | /// ``` | |
1131 | /// use std::collections::HashSet; | |
1132 | /// | |
1133 | /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); | |
1134 | /// let b: HashSet<_> = vec![2, 3, 4].into_iter().collect(); | |
1135 | /// | |
1136 | /// let set = &a & &b; | |
1137 | /// | |
1138 | /// let mut i = 0; | |
1139 | /// let expected = [2, 3]; | |
1140 | /// for x in &set { | |
1141 | /// assert!(expected.contains(x)); | |
1142 | /// i += 1; | |
1143 | /// } | |
1144 | /// assert_eq!(i, expected.len()); | |
1145 | /// ``` | |
1146 | fn bitand(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1147 | self.intersection(rhs).cloned().collect() | |
1148 | } | |
1149 | } | |
1150 | ||
1151 | #[stable(feature = "rust1", since = "1.0.0")] | |
1152 | impl<T, S> BitXor<&HashSet<T, S>> for &HashSet<T, S> | |
1153 | where | |
1154 | T: Eq + Hash + Clone, | |
1155 | S: BuildHasher + Default, | |
1156 | { | |
1157 | type Output = HashSet<T, S>; | |
1158 | ||
1159 | /// Returns the symmetric difference of `self` and `rhs` as a new `HashSet<T, S>`. | |
1160 | /// | |
1161 | /// # Examples | |
1162 | /// | |
1163 | /// ``` | |
1164 | /// use std::collections::HashSet; | |
1165 | /// | |
1166 | /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); | |
1167 | /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect(); | |
1168 | /// | |
1169 | /// let set = &a ^ &b; | |
1170 | /// | |
1171 | /// let mut i = 0; | |
1172 | /// let expected = [1, 2, 4, 5]; | |
1173 | /// for x in &set { | |
1174 | /// assert!(expected.contains(x)); | |
1175 | /// i += 1; | |
1176 | /// } | |
1177 | /// assert_eq!(i, expected.len()); | |
1178 | /// ``` | |
1179 | fn bitxor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1180 | self.symmetric_difference(rhs).cloned().collect() | |
1181 | } | |
1182 | } | |
1183 | ||
1184 | #[stable(feature = "rust1", since = "1.0.0")] | |
1185 | impl<T, S> Sub<&HashSet<T, S>> for &HashSet<T, S> | |
1186 | where | |
1187 | T: Eq + Hash + Clone, | |
1188 | S: BuildHasher + Default, | |
1189 | { | |
1190 | type Output = HashSet<T, S>; | |
1191 | ||
1192 | /// Returns the difference of `self` and `rhs` as a new `HashSet<T, S>`. | |
1193 | /// | |
1194 | /// # Examples | |
1195 | /// | |
1196 | /// ``` | |
1197 | /// use std::collections::HashSet; | |
1198 | /// | |
1199 | /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); | |
1200 | /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect(); | |
1201 | /// | |
1202 | /// let set = &a - &b; | |
1203 | /// | |
1204 | /// let mut i = 0; | |
1205 | /// let expected = [1, 2]; | |
1206 | /// for x in &set { | |
1207 | /// assert!(expected.contains(x)); | |
1208 | /// i += 1; | |
1209 | /// } | |
1210 | /// assert_eq!(i, expected.len()); | |
1211 | /// ``` | |
1212 | fn sub(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1213 | self.difference(rhs).cloned().collect() | |
1214 | } | |
1215 | } | |
1216 | ||
1217 | /// An iterator over the items of a `HashSet`. | |
1218 | /// | |
1219 | /// This `struct` is created by the [`iter`] method on [`HashSet`]. | |
1220 | /// See its documentation for more. | |
1221 | /// | |
1222 | /// [`iter`]: HashSet::iter | |
1223 | /// | |
1224 | /// # Examples | |
1225 | /// | |
1226 | /// ``` | |
1227 | /// use std::collections::HashSet; | |
1228 | /// | |
1229 | /// let a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1230 | /// | |
1231 | /// let mut iter = a.iter(); | |
1232 | /// ``` | |
1233 | #[stable(feature = "rust1", since = "1.0.0")] | |
1234 | pub struct Iter<'a, K: 'a> { | |
1235 | base: base::Iter<'a, K>, | |
1236 | } | |
1237 | ||
1238 | /// An owning iterator over the items of a `HashSet`. | |
1239 | /// | |
1240 | /// This `struct` is created by the [`into_iter`] method on [`HashSet`] | |
1241 | /// (provided by the [`IntoIterator`] trait). See its documentation for more. | |
1242 | /// | |
1243 | /// [`into_iter`]: IntoIterator::into_iter | |
1244 | /// [`IntoIterator`]: crate::iter::IntoIterator | |
1245 | /// | |
1246 | /// # Examples | |
1247 | /// | |
1248 | /// ``` | |
1249 | /// use std::collections::HashSet; | |
1250 | /// | |
1251 | /// let a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1252 | /// | |
1253 | /// let mut iter = a.into_iter(); | |
1254 | /// ``` | |
1255 | #[stable(feature = "rust1", since = "1.0.0")] | |
1256 | pub struct IntoIter<K> { | |
1257 | base: base::IntoIter<K>, | |
1258 | } | |
1259 | ||
1260 | /// A draining iterator over the items of a `HashSet`. | |
1261 | /// | |
1262 | /// This `struct` is created by the [`drain`] method on [`HashSet`]. | |
1263 | /// See its documentation for more. | |
1264 | /// | |
1265 | /// [`drain`]: HashSet::drain | |
1266 | /// | |
1267 | /// # Examples | |
1268 | /// | |
1269 | /// ``` | |
1270 | /// use std::collections::HashSet; | |
1271 | /// | |
1272 | /// let mut a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1273 | /// | |
1274 | /// let mut drain = a.drain(); | |
1275 | /// ``` | |
1276 | #[stable(feature = "rust1", since = "1.0.0")] | |
1277 | pub struct Drain<'a, K: 'a> { | |
1278 | base: base::Drain<'a, K>, | |
1279 | } | |
1280 | ||
1281 | /// A draining, filtering iterator over the items of a `HashSet`. | |
1282 | /// | |
1283 | /// This `struct` is created by the [`drain_filter`] method on [`HashSet`]. | |
1284 | /// | |
1285 | /// [`drain_filter`]: HashSet::drain_filter | |
1286 | /// | |
1287 | /// # Examples | |
1288 | /// | |
1289 | /// ``` | |
1290 | /// #![feature(hash_drain_filter)] | |
1291 | /// | |
1292 | /// use std::collections::HashSet; | |
1293 | /// | |
1294 | /// let mut a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1295 | /// | |
1296 | /// let mut drain_filtered = a.drain_filter(|v| v % 2 == 0); | |
1297 | /// ``` | |
1298 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1299 | pub struct DrainFilter<'a, K, F> | |
1300 | where | |
1301 | F: FnMut(&K) -> bool, | |
1302 | { | |
1303 | base: base::DrainFilter<'a, K, F>, | |
1304 | } | |
1305 | ||
1306 | /// A lazy iterator producing elements in the intersection of `HashSet`s. | |
1307 | /// | |
1308 | /// This `struct` is created by the [`intersection`] method on [`HashSet`]. | |
1309 | /// See its documentation for more. | |
1310 | /// | |
1311 | /// [`intersection`]: HashSet::intersection | |
1312 | /// | |
1313 | /// # Examples | |
1314 | /// | |
1315 | /// ``` | |
1316 | /// use std::collections::HashSet; | |
1317 | /// | |
1318 | /// let a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1319 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
1320 | /// | |
1321 | /// let mut intersection = a.intersection(&b); | |
1322 | /// ``` | |
1323 | #[must_use = "this returns the intersection as an iterator, \ | |
1324 | without modifying either input set"] | |
1325 | #[stable(feature = "rust1", since = "1.0.0")] | |
1326 | pub struct Intersection<'a, T: 'a, S: 'a> { | |
1327 | // iterator of the first set | |
1328 | iter: Iter<'a, T>, | |
1329 | // the second set | |
1330 | other: &'a HashSet<T, S>, | |
1331 | } | |
1332 | ||
1333 | /// A lazy iterator producing elements in the difference of `HashSet`s. | |
1334 | /// | |
1335 | /// This `struct` is created by the [`difference`] method on [`HashSet`]. | |
1336 | /// See its documentation for more. | |
1337 | /// | |
1338 | /// [`difference`]: HashSet::difference | |
1339 | /// | |
1340 | /// # Examples | |
1341 | /// | |
1342 | /// ``` | |
1343 | /// use std::collections::HashSet; | |
1344 | /// | |
1345 | /// let a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1346 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
1347 | /// | |
1348 | /// let mut difference = a.difference(&b); | |
1349 | /// ``` | |
1350 | #[must_use = "this returns the difference as an iterator, \ | |
1351 | without modifying either input set"] | |
1352 | #[stable(feature = "rust1", since = "1.0.0")] | |
1353 | pub struct Difference<'a, T: 'a, S: 'a> { | |
1354 | // iterator of the first set | |
1355 | iter: Iter<'a, T>, | |
1356 | // the second set | |
1357 | other: &'a HashSet<T, S>, | |
1358 | } | |
1359 | ||
1360 | /// A lazy iterator producing elements in the symmetric difference of `HashSet`s. | |
1361 | /// | |
1362 | /// This `struct` is created by the [`symmetric_difference`] method on | |
1363 | /// [`HashSet`]. See its documentation for more. | |
1364 | /// | |
1365 | /// [`symmetric_difference`]: HashSet::symmetric_difference | |
1366 | /// | |
1367 | /// # Examples | |
1368 | /// | |
1369 | /// ``` | |
1370 | /// use std::collections::HashSet; | |
1371 | /// | |
1372 | /// let a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1373 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
1374 | /// | |
1375 | /// let mut intersection = a.symmetric_difference(&b); | |
1376 | /// ``` | |
1377 | #[must_use = "this returns the difference as an iterator, \ | |
1378 | without modifying either input set"] | |
1379 | #[stable(feature = "rust1", since = "1.0.0")] | |
1380 | pub struct SymmetricDifference<'a, T: 'a, S: 'a> { | |
1381 | iter: Chain<Difference<'a, T, S>, Difference<'a, T, S>>, | |
1382 | } | |
1383 | ||
1384 | /// A lazy iterator producing elements in the union of `HashSet`s. | |
1385 | /// | |
1386 | /// This `struct` is created by the [`union`] method on [`HashSet`]. | |
1387 | /// See its documentation for more. | |
1388 | /// | |
1389 | /// [`union`]: HashSet::union | |
1390 | /// | |
1391 | /// # Examples | |
1392 | /// | |
1393 | /// ``` | |
1394 | /// use std::collections::HashSet; | |
1395 | /// | |
1396 | /// let a: HashSet<u32> = vec![1, 2, 3].into_iter().collect(); | |
1397 | /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); | |
1398 | /// | |
1399 | /// let mut union_iter = a.union(&b); | |
1400 | /// ``` | |
1401 | #[must_use = "this returns the union as an iterator, \ | |
1402 | without modifying either input set"] | |
1403 | #[stable(feature = "rust1", since = "1.0.0")] | |
1404 | pub struct Union<'a, T: 'a, S: 'a> { | |
1405 | iter: Chain<Iter<'a, T>, Difference<'a, T, S>>, | |
1406 | } | |
1407 | ||
1408 | #[stable(feature = "rust1", since = "1.0.0")] | |
1409 | impl<'a, T, S> IntoIterator for &'a HashSet<T, S> { | |
1410 | type Item = &'a T; | |
1411 | type IntoIter = Iter<'a, T>; | |
1412 | ||
1413 | #[inline] | |
1414 | fn into_iter(self) -> Iter<'a, T> { | |
1415 | self.iter() | |
1416 | } | |
1417 | } | |
1418 | ||
1419 | #[stable(feature = "rust1", since = "1.0.0")] | |
1420 | impl<T, S> IntoIterator for HashSet<T, S> { | |
1421 | type Item = T; | |
1422 | type IntoIter = IntoIter<T>; | |
1423 | ||
1424 | /// Creates a consuming iterator, that is, one that moves each value out | |
1425 | /// of the set in arbitrary order. The set cannot be used after calling | |
1426 | /// this. | |
1427 | /// | |
1428 | /// # Examples | |
1429 | /// | |
1430 | /// ``` | |
1431 | /// use std::collections::HashSet; | |
1432 | /// let mut set = HashSet::new(); | |
1433 | /// set.insert("a".to_string()); | |
1434 | /// set.insert("b".to_string()); | |
1435 | /// | |
1436 | /// // Not possible to collect to a Vec<String> with a regular `.iter()`. | |
1437 | /// let v: Vec<String> = set.into_iter().collect(); | |
1438 | /// | |
1439 | /// // Will print in an arbitrary order. | |
1440 | /// for x in &v { | |
1441 | /// println!("{}", x); | |
1442 | /// } | |
1443 | /// ``` | |
1444 | #[inline] | |
1445 | fn into_iter(self) -> IntoIter<T> { | |
1446 | IntoIter { base: self.base.into_iter() } | |
1447 | } | |
1448 | } | |
1449 | ||
1450 | #[stable(feature = "rust1", since = "1.0.0")] | |
1451 | impl<K> Clone for Iter<'_, K> { | |
1452 | #[inline] | |
1453 | fn clone(&self) -> Self { | |
1454 | Iter { base: self.base.clone() } | |
1455 | } | |
1456 | } | |
1457 | #[stable(feature = "rust1", since = "1.0.0")] | |
1458 | impl<'a, K> Iterator for Iter<'a, K> { | |
1459 | type Item = &'a K; | |
1460 | ||
1461 | #[inline] | |
1462 | fn next(&mut self) -> Option<&'a K> { | |
1463 | self.base.next() | |
1464 | } | |
1465 | #[inline] | |
1466 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1467 | self.base.size_hint() | |
1468 | } | |
1469 | } | |
1470 | #[stable(feature = "rust1", since = "1.0.0")] | |
1471 | impl<K> ExactSizeIterator for Iter<'_, K> { | |
1472 | #[inline] | |
1473 | fn len(&self) -> usize { | |
1474 | self.base.len() | |
1475 | } | |
1476 | } | |
1477 | #[stable(feature = "fused", since = "1.26.0")] | |
1478 | impl<K> FusedIterator for Iter<'_, K> {} | |
1479 | ||
1480 | #[stable(feature = "std_debug", since = "1.16.0")] | |
1481 | impl<K: fmt::Debug> fmt::Debug for Iter<'_, K> { | |
1482 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1483 | f.debug_list().entries(self.clone()).finish() | |
1484 | } | |
1485 | } | |
1486 | ||
1487 | #[stable(feature = "rust1", since = "1.0.0")] | |
1488 | impl<K> Iterator for IntoIter<K> { | |
1489 | type Item = K; | |
1490 | ||
1491 | #[inline] | |
1492 | fn next(&mut self) -> Option<K> { | |
1493 | self.base.next() | |
1494 | } | |
1495 | #[inline] | |
1496 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1497 | self.base.size_hint() | |
1498 | } | |
1499 | } | |
1500 | #[stable(feature = "rust1", since = "1.0.0")] | |
1501 | impl<K> ExactSizeIterator for IntoIter<K> { | |
1502 | #[inline] | |
1503 | fn len(&self) -> usize { | |
1504 | self.base.len() | |
1505 | } | |
1506 | } | |
1507 | #[stable(feature = "fused", since = "1.26.0")] | |
1508 | impl<K> FusedIterator for IntoIter<K> {} | |
1509 | ||
1510 | #[stable(feature = "std_debug", since = "1.16.0")] | |
1511 | impl<K: fmt::Debug> fmt::Debug for IntoIter<K> { | |
1512 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1513 | fmt::Debug::fmt(&self.base, f) | |
1514 | } | |
1515 | } | |
1516 | ||
1517 | #[stable(feature = "rust1", since = "1.0.0")] | |
1518 | impl<'a, K> Iterator for Drain<'a, K> { | |
1519 | type Item = K; | |
1520 | ||
1521 | #[inline] | |
1522 | fn next(&mut self) -> Option<K> { | |
1523 | self.base.next() | |
1524 | } | |
1525 | #[inline] | |
1526 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1527 | self.base.size_hint() | |
1528 | } | |
1529 | } | |
1530 | #[stable(feature = "rust1", since = "1.0.0")] | |
1531 | impl<K> ExactSizeIterator for Drain<'_, K> { | |
1532 | #[inline] | |
1533 | fn len(&self) -> usize { | |
1534 | self.base.len() | |
1535 | } | |
1536 | } | |
1537 | #[stable(feature = "fused", since = "1.26.0")] | |
1538 | impl<K> FusedIterator for Drain<'_, K> {} | |
1539 | ||
1540 | #[stable(feature = "std_debug", since = "1.16.0")] | |
1541 | impl<K: fmt::Debug> fmt::Debug for Drain<'_, K> { | |
1542 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1543 | fmt::Debug::fmt(&self.base, f) | |
1544 | } | |
1545 | } | |
1546 | ||
1547 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1548 | impl<K, F> Iterator for DrainFilter<'_, K, F> | |
1549 | where | |
1550 | F: FnMut(&K) -> bool, | |
1551 | { | |
1552 | type Item = K; | |
1553 | ||
1554 | #[inline] | |
1555 | fn next(&mut self) -> Option<K> { | |
1556 | self.base.next() | |
1557 | } | |
1558 | #[inline] | |
1559 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1560 | self.base.size_hint() | |
1561 | } | |
1562 | } | |
1563 | ||
1564 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1565 | impl<K, F> FusedIterator for DrainFilter<'_, K, F> where F: FnMut(&K) -> bool {} | |
1566 | ||
1567 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1568 | impl<'a, K, F> fmt::Debug for DrainFilter<'a, K, F> | |
1569 | where | |
1570 | F: FnMut(&K) -> bool, | |
1571 | { | |
1572 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1573 | f.debug_struct("DrainFilter").finish_non_exhaustive() | |
1574 | } | |
1575 | } | |
1576 | ||
1577 | #[stable(feature = "rust1", since = "1.0.0")] | |
1578 | impl<T, S> Clone for Intersection<'_, T, S> { | |
1579 | #[inline] | |
1580 | fn clone(&self) -> Self { | |
1581 | Intersection { iter: self.iter.clone(), ..*self } | |
1582 | } | |
1583 | } | |
1584 | ||
1585 | #[stable(feature = "rust1", since = "1.0.0")] | |
1586 | impl<'a, T, S> Iterator for Intersection<'a, T, S> | |
1587 | where | |
1588 | T: Eq + Hash, | |
1589 | S: BuildHasher, | |
1590 | { | |
1591 | type Item = &'a T; | |
1592 | ||
1593 | #[inline] | |
1594 | fn next(&mut self) -> Option<&'a T> { | |
1595 | loop { | |
1596 | let elt = self.iter.next()?; | |
1597 | if self.other.contains(elt) { | |
1598 | return Some(elt); | |
1599 | } | |
1600 | } | |
1601 | } | |
1602 | ||
1603 | #[inline] | |
1604 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1605 | let (_, upper) = self.iter.size_hint(); | |
1606 | (0, upper) | |
1607 | } | |
1608 | } | |
1609 | ||
1610 | #[stable(feature = "std_debug", since = "1.16.0")] | |
1611 | impl<T, S> fmt::Debug for Intersection<'_, T, S> | |
1612 | where | |
1613 | T: fmt::Debug + Eq + Hash, | |
1614 | S: BuildHasher, | |
1615 | { | |
1616 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1617 | f.debug_list().entries(self.clone()).finish() | |
1618 | } | |
1619 | } | |
1620 | ||
1621 | #[stable(feature = "fused", since = "1.26.0")] | |
1622 | impl<T, S> FusedIterator for Intersection<'_, T, S> | |
1623 | where | |
1624 | T: Eq + Hash, | |
1625 | S: BuildHasher, | |
1626 | { | |
1627 | } | |
1628 | ||
1629 | #[stable(feature = "rust1", since = "1.0.0")] | |
1630 | impl<T, S> Clone for Difference<'_, T, S> { | |
1631 | #[inline] | |
1632 | fn clone(&self) -> Self { | |
1633 | Difference { iter: self.iter.clone(), ..*self } | |
1634 | } | |
1635 | } | |
1636 | ||
1637 | #[stable(feature = "rust1", since = "1.0.0")] | |
1638 | impl<'a, T, S> Iterator for Difference<'a, T, S> | |
1639 | where | |
1640 | T: Eq + Hash, | |
1641 | S: BuildHasher, | |
1642 | { | |
1643 | type Item = &'a T; | |
1644 | ||
1645 | #[inline] | |
1646 | fn next(&mut self) -> Option<&'a T> { | |
1647 | loop { | |
1648 | let elt = self.iter.next()?; | |
1649 | if !self.other.contains(elt) { | |
1650 | return Some(elt); | |
1651 | } | |
1652 | } | |
1653 | } | |
1654 | ||
1655 | #[inline] | |
1656 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1657 | let (_, upper) = self.iter.size_hint(); | |
1658 | (0, upper) | |
1659 | } | |
1660 | } | |
1661 | ||
1662 | #[stable(feature = "fused", since = "1.26.0")] | |
1663 | impl<T, S> FusedIterator for Difference<'_, T, S> | |
1664 | where | |
1665 | T: Eq + Hash, | |
1666 | S: BuildHasher, | |
1667 | { | |
1668 | } | |
1669 | ||
1670 | #[stable(feature = "std_debug", since = "1.16.0")] | |
1671 | impl<T, S> fmt::Debug for Difference<'_, T, S> | |
1672 | where | |
1673 | T: fmt::Debug + Eq + Hash, | |
1674 | S: BuildHasher, | |
1675 | { | |
1676 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1677 | f.debug_list().entries(self.clone()).finish() | |
1678 | } | |
1679 | } | |
1680 | ||
1681 | #[stable(feature = "rust1", since = "1.0.0")] | |
1682 | impl<T, S> Clone for SymmetricDifference<'_, T, S> { | |
1683 | #[inline] | |
1684 | fn clone(&self) -> Self { | |
1685 | SymmetricDifference { iter: self.iter.clone() } | |
1686 | } | |
1687 | } | |
1688 | ||
1689 | #[stable(feature = "rust1", since = "1.0.0")] | |
1690 | impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S> | |
1691 | where | |
1692 | T: Eq + Hash, | |
1693 | S: BuildHasher, | |
1694 | { | |
1695 | type Item = &'a T; | |
1696 | ||
1697 | #[inline] | |
1698 | fn next(&mut self) -> Option<&'a T> { | |
1699 | self.iter.next() | |
1700 | } | |
1701 | #[inline] | |
1702 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1703 | self.iter.size_hint() | |
1704 | } | |
1705 | } | |
1706 | ||
1707 | #[stable(feature = "fused", since = "1.26.0")] | |
1708 | impl<T, S> FusedIterator for SymmetricDifference<'_, T, S> | |
1709 | where | |
1710 | T: Eq + Hash, | |
1711 | S: BuildHasher, | |
1712 | { | |
1713 | } | |
1714 | ||
1715 | #[stable(feature = "std_debug", since = "1.16.0")] | |
1716 | impl<T, S> fmt::Debug for SymmetricDifference<'_, T, S> | |
1717 | where | |
1718 | T: fmt::Debug + Eq + Hash, | |
1719 | S: BuildHasher, | |
1720 | { | |
1721 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1722 | f.debug_list().entries(self.clone()).finish() | |
1723 | } | |
1724 | } | |
1725 | ||
1726 | #[stable(feature = "rust1", since = "1.0.0")] | |
1727 | impl<T, S> Clone for Union<'_, T, S> { | |
1728 | #[inline] | |
1729 | fn clone(&self) -> Self { | |
1730 | Union { iter: self.iter.clone() } | |
1731 | } | |
1732 | } | |
1733 | ||
1734 | #[stable(feature = "fused", since = "1.26.0")] | |
1735 | impl<T, S> FusedIterator for Union<'_, T, S> | |
1736 | where | |
1737 | T: Eq + Hash, | |
1738 | S: BuildHasher, | |
1739 | { | |
1740 | } | |
1741 | ||
1742 | #[stable(feature = "std_debug", since = "1.16.0")] | |
1743 | impl<T, S> fmt::Debug for Union<'_, T, S> | |
1744 | where | |
1745 | T: fmt::Debug + Eq + Hash, | |
1746 | S: BuildHasher, | |
1747 | { | |
1748 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
1749 | f.debug_list().entries(self.clone()).finish() | |
1750 | } | |
1751 | } | |
1752 | ||
1753 | #[stable(feature = "rust1", since = "1.0.0")] | |
1754 | impl<'a, T, S> Iterator for Union<'a, T, S> | |
1755 | where | |
1756 | T: Eq + Hash, | |
1757 | S: BuildHasher, | |
1758 | { | |
1759 | type Item = &'a T; | |
1760 | ||
1761 | #[inline] | |
1762 | fn next(&mut self) -> Option<&'a T> { | |
1763 | self.iter.next() | |
1764 | } | |
1765 | #[inline] | |
1766 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1767 | self.iter.size_hint() | |
1768 | } | |
1769 | } | |
1770 | ||
1771 | #[allow(dead_code)] | |
1772 | fn assert_covariance() { | |
1773 | fn set<'new>(v: HashSet<&'static str>) -> HashSet<&'new str> { | |
1774 | v | |
1775 | } | |
1776 | fn iter<'a, 'new>(v: Iter<'a, &'static str>) -> Iter<'a, &'new str> { | |
1777 | v | |
1778 | } | |
1779 | fn into_iter<'new>(v: IntoIter<&'static str>) -> IntoIter<&'new str> { | |
1780 | v | |
1781 | } | |
1782 | fn difference<'a, 'new>( | |
1783 | v: Difference<'a, &'static str, RandomState>, | |
1784 | ) -> Difference<'a, &'new str, RandomState> { | |
1785 | v | |
1786 | } | |
1787 | fn symmetric_difference<'a, 'new>( | |
1788 | v: SymmetricDifference<'a, &'static str, RandomState>, | |
1789 | ) -> SymmetricDifference<'a, &'new str, RandomState> { | |
1790 | v | |
1791 | } | |
1792 | fn intersection<'a, 'new>( | |
1793 | v: Intersection<'a, &'static str, RandomState>, | |
1794 | ) -> Intersection<'a, &'new str, RandomState> { | |
1795 | v | |
1796 | } | |
1797 | fn union<'a, 'new>( | |
1798 | v: Union<'a, &'static str, RandomState>, | |
1799 | ) -> Union<'a, &'new str, RandomState> { | |
1800 | v | |
1801 | } | |
1802 | fn drain<'new>(d: Drain<'static, &'static str>) -> Drain<'new, &'new str> { | |
1803 | d | |
1804 | } | |
1805 | } |