1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // ignore-lexer-test FIXME #15883
14 use self::SearchResult::*;
15 use self::VacantEntryState::*;
17 use borrow::BorrowFrom;
19 use cmp::{max, Eq, Equiv, PartialEq};
22 use hash::{Hash, Hasher, RandomSipHasher};
23 use iter::{mod, Iterator, IteratorExt, FromIterator, Extend, Map};
25 use mem::{mod, replace};
26 use num::{Int, UnsignedInt};
27 use ops::{Deref, FnMut, Index, IndexMut};
29 use option::Option::{Some, None};
31 use result::Result::{Ok, Err};
43 use super::table::BucketState::{
48 const INITIAL_LOG2_CAP: uint = 5;
49 pub const INITIAL_CAPACITY: uint = 1 << INITIAL_LOG2_CAP; // 2^5
51 /// The default behavior of HashMap implements a load factor of 90.9%.
52 /// This behavior is characterized by the following condition:
54 /// - if size > 0.909 * capacity: grow the map
56 struct DefaultResizePolicy;
58 impl DefaultResizePolicy {
59 fn new() -> DefaultResizePolicy {
64 fn min_capacity(&self, usable_size: uint) -> uint {
65 // Here, we are rephrasing the logic by specifying the lower limit
68 // - if `cap < size * 1.1`: grow the map
72 /// An inverse of `min_capacity`, approximately.
74 fn usable_capacity(&self, cap: uint) -> uint {
75 // As the number of entries approaches usable capacity,
76 // min_capacity(size) must be smaller than the internal capacity,
77 // so that the map is not resized:
78 // `min_capacity(usable_capacity(x)) <= x`.
79 // The lef-hand side can only be smaller due to flooring by integer
82 // This doesn't have to be checked for overflow since allocation size
83 // in bytes will overflow earlier than multiplication by 10.
89 fn test_resize_policy() {
91 let rp = DefaultResizePolicy;
92 for n in range(0u, 1000) {
93 assert!(rp.min_capacity(rp.usable_capacity(n)) <= n);
94 assert!(rp.usable_capacity(rp.min_capacity(n)) <= n);
98 // The main performance trick in this hashmap is called Robin Hood Hashing.
99 // It gains its excellent performance from one essential operation:
101 // If an insertion collides with an existing element, and that element's
102 // "probe distance" (how far away the element is from its ideal location)
103 // is higher than how far we've already probed, swap the elements.
105 // This massively lowers variance in probe distance, and allows us to get very
106 // high load factors with good performance. The 90% load factor I use is rather
109 // > Why a load factor of approximately 90%?
111 // In general, all the distances to initial buckets will converge on the mean.
112 // At a load factor of α, the odds of finding the target bucket after k
113 // probes is approximately 1-α^k. If we set this equal to 50% (since we converge
114 // on the mean) and set k=8 (64-byte cache line / 8-byte hash), α=0.92. I round
115 // this down to make the math easier on the CPU and avoid its FPU.
116 // Since on average we start the probing in the middle of a cache line, this
117 // strategy pulls in two cache lines of hashes on every lookup. I think that's
118 // pretty good, but if you want to trade off some space, it could go down to one
119 // cache line on average with an α of 0.84.
121 // > Wait, what? Where did you get 1-α^k from?
123 // On the first probe, your odds of a collision with an existing element is α.
124 // The odds of doing this twice in a row is approximately α^2. For three times,
125 // α^3, etc. Therefore, the odds of colliding k times is α^k. The odds of NOT
126 // colliding after k tries is 1-α^k.
128 // The paper from 1986 cited below mentions an implementation which keeps track
129 // of the distance-to-initial-bucket histogram. This approach is not suitable
130 // for modern architectures because it requires maintaining an internal data
131 // structure. This allows very good first guesses, but we are most concerned
132 // with guessing entire cache lines, not individual indexes. Furthermore, array
133 // accesses are no longer linear and in one direction, as we have now. There
134 // is also memory and cache pressure that this would entail that would be very
135 // difficult to properly see in a microbenchmark.
137 // ## Future Improvements (FIXME!)
139 // Allow the load factor to be changed dynamically and/or at initialization.
141 // Also, would it be possible for us to reuse storage when growing the
142 // underlying table? This is exactly the use case for 'realloc', and may
143 // be worth exploring.
145 // ## Future Optimizations (FIXME!)
147 // Another possible design choice that I made without any real reason is
148 // parameterizing the raw table over keys and values. Technically, all we need
149 // is the size and alignment of keys and values, and the code should be just as
150 // efficient (well, we might need one for power-of-two size and one for not...).
151 // This has the potential to reduce code bloat in rust executables, without
152 // really losing anything except 4 words (key size, key alignment, val size,
153 // val alignment) which can be passed in to every call of a `RawTable` function.
154 // This would definitely be an avenue worth exploring if people start complaining
155 // about the size of rust executables.
157 // Annotate exceedingly likely branches in `table::make_hash`
158 // and `search_hashed` to reduce instruction cache pressure
159 // and mispredictions once it becomes possible (blocked on issue #11092).
161 // Shrinking the table could simply reallocate in place after moving buckets
162 // to the first half.
164 // The growth algorithm (fragment of the Proof of Correctness)
165 // --------------------
167 // The growth algorithm is basically a fast path of the naive reinsertion-
168 // during-resize algorithm. Other paths should never be taken.
170 // Consider growing a robin hood hashtable of capacity n. Normally, we do this
171 // by allocating a new table of capacity `2n`, and then individually reinsert
172 // each element in the old table into the new one. This guarantees that the
173 // new table is a valid robin hood hashtable with all the desired statistical
174 // properties. Remark that the order we reinsert the elements in should not
175 // matter. For simplicity and efficiency, we will consider only linear
176 // reinsertions, which consist of reinserting all elements in the old table
177 // into the new one by increasing order of index. However we will not be
178 // starting our reinsertions from index 0 in general. If we start from index
179 // i, for the purpose of reinsertion we will consider all elements with real
180 // index j < i to have virtual index n + j.
182 // Our hash generation scheme consists of generating a 64-bit hash and
183 // truncating the most significant bits. When moving to the new table, we
184 // simply introduce a new bit to the front of the hash. Therefore, if an
185 // elements has ideal index i in the old table, it can have one of two ideal
186 // locations in the new table. If the new bit is 0, then the new ideal index
187 // is i. If the new bit is 1, then the new ideal index is n + i. Intutively,
188 // we are producing two independent tables of size n, and for each element we
189 // independently choose which table to insert it into with equal probability.
190 // However the rather than wrapping around themselves on overflowing their
191 // indexes, the first table overflows into the first, and the first into the
192 // second. Visually, our new table will look something like:
194 // [yy_xxx_xxxx_xxx|xx_yyy_yyyy_yyy]
196 // Where x's are elements inserted into the first table, y's are elements
197 // inserted into the second, and _'s are empty sections. We now define a few
198 // key concepts that we will use later. Note that this is a very abstract
199 // perspective of the table. A real resized table would be at least half
202 // Theorem: A linear robin hood reinsertion from the first ideal element
203 // produces identical results to a linear naive reinsertion from the same
206 // FIXME(Gankro, pczarn): review the proof and put it all in a separate doc.rs
208 /// A hash map implementation which uses linear probing with Robin
209 /// Hood bucket stealing.
211 /// The hashes are all keyed by the task-local random number generator
212 /// on creation by default. This means that the ordering of the keys is
213 /// randomized, but makes the tables more resistant to
214 /// denial-of-service attacks (Hash DoS). This behaviour can be
215 /// overridden with one of the constructors.
217 /// It is required that the keys implement the `Eq` and `Hash` traits, although
218 /// this can frequently be achieved by using `#[deriving(Eq, Hash)]`.
220 /// Relevant papers/articles:
222 /// 1. Pedro Celis. ["Robin Hood Hashing"](https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf)
223 /// 2. Emmanuel Goossaert. ["Robin Hood
224 /// hashing"](http://codecapsule.com/2013/11/11/robin-hood-hashing/)
225 /// 3. Emmanuel Goossaert. ["Robin Hood hashing: backward shift
226 /// deletion"](http://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/)
231 /// use std::collections::HashMap;
233 /// // type inference lets us omit an explicit type signature (which
234 /// // would be `HashMap<&str, &str>` in this example).
235 /// let mut book_reviews = HashMap::new();
237 /// // review some books.
238 /// book_reviews.insert("Adventures of Huckleberry Finn", "My favorite book.");
239 /// book_reviews.insert("Grimms' Fairy Tales", "Masterpiece.");
240 /// book_reviews.insert("Pride and Prejudice", "Very enjoyable.");
241 /// book_reviews.insert("The Adventures of Sherlock Holmes", "Eye lyked it alot.");
243 /// // check for a specific one.
244 /// if !book_reviews.contains_key(&("Les Misérables")) {
245 /// println!("We've got {} reviews, but Les Misérables ain't one.",
246 /// book_reviews.len());
249 /// // oops, this review has a lot of spelling mistakes, let's delete it.
250 /// book_reviews.remove(&("The Adventures of Sherlock Holmes"));
252 /// // look up the values associated with some keys.
253 /// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"];
254 /// for book in to_find.iter() {
255 /// match book_reviews.get(book) {
256 /// Some(review) => println!("{}: {}", *book, *review),
257 /// None => println!("{} is unreviewed.", *book)
261 /// // iterate over everything.
262 /// for (book, review) in book_reviews.iter() {
263 /// println!("{}: \"{}\"", *book, *review);
267 /// The easiest way to use `HashMap` with a custom type as key is to derive `Eq` and `Hash`.
268 /// We must also derive `PartialEq`.
271 /// use std::collections::HashMap;
273 /// #[deriving(Hash, Eq, PartialEq, Show)]
280 /// /// Create a new Viking.
281 /// fn new(name: &str, country: &str) -> Viking {
282 /// Viking { name: name.to_string(), country: country.to_string() }
286 /// // Use a HashMap to store the vikings' health points.
287 /// let mut vikings = HashMap::new();
289 /// vikings.insert(Viking::new("Einar", "Norway"), 25u);
290 /// vikings.insert(Viking::new("Olaf", "Denmark"), 24u);
291 /// vikings.insert(Viking::new("Harald", "Iceland"), 12u);
293 /// // Use derived implementation to print the status of the vikings.
294 /// for (viking, health) in vikings.iter() {
295 /// println!("{} has {} hp", viking, health);
300 pub struct HashMap<K, V, H = RandomSipHasher> {
301 // All hashes are keyed on these values, to prevent hash collision attacks.
304 table: RawTable<K, V>,
306 resize_policy: DefaultResizePolicy,
309 /// Search for a pre-hashed key.
310 fn search_hashed<K, V, M, F>(table: M,
313 -> SearchResult<K, V, M> where
314 M: Deref<Target=RawTable<K, V>>,
315 F: FnMut(&K) -> bool,
317 let size = table.size();
318 let mut probe = Bucket::new(table, hash);
319 let ib = probe.index();
321 while probe.index() != ib + size {
322 let full = match probe.peek() {
323 Empty(b) => return TableRef(b.into_table()), // hit an empty bucket
327 if full.distance() + ib < full.index() {
328 // We can finish the search early if we hit any bucket
329 // with a lower distance to initial bucket than we've probed.
330 return TableRef(full.into_table());
333 // If the hash doesn't match, it can't be this one..
334 if hash == full.hash() {
335 // If the key doesn't match, it can't be this one..
336 if is_match(full.read().0) {
337 return FoundExisting(full);
344 TableRef(probe.into_table())
347 fn pop_internal<K, V>(starting_bucket: FullBucketMut<K, V>) -> (K, V) {
348 let (empty, retkey, retval) = starting_bucket.take();
349 let mut gap = match empty.gap_peek() {
351 None => return (retkey, retval)
354 while gap.full().distance() != 0 {
355 gap = match gap.shift() {
361 // Now we've done all our shifting. Return the value we grabbed earlier.
365 /// Perform robin hood bucket stealing at the given `bucket`. You must
366 /// also pass the position of that bucket's initial bucket so we don't have
367 /// to recalculate it.
369 /// `hash`, `k`, and `v` are the elements to "robin hood" into the hashtable.
370 fn robin_hood<'a, K: 'a, V: 'a>(mut bucket: FullBucketMut<'a, K, V>,
376 let starting_index = bucket.index();
378 let table = bucket.table(); // FIXME "lifetime too short".
381 // There can be at most `size - dib` buckets to displace, because
382 // in the worst case, there are `size` elements and we already are
383 // `distance` buckets away from the initial one.
384 let idx_end = starting_index + size - bucket.distance();
387 let (old_hash, old_key, old_val) = bucket.replace(hash, k, v);
389 let probe = bucket.next();
390 assert!(probe.index() != idx_end);
392 let full_bucket = match probe.peek() {
395 let b = bucket.put(old_hash, old_key, old_val);
396 // Now that it's stolen, just read the value's pointer
397 // right out of the table!
398 return Bucket::at_index(b.into_table(), starting_index)
404 Full(bucket) => bucket
407 let probe_ib = full_bucket.index() - full_bucket.distance();
409 bucket = full_bucket;
411 // Robin hood! Steal the spot.
423 /// A result that works like Option<FullBucket<..>> but preserves
424 /// the reference that grants us access to the table in any case.
425 enum SearchResult<K, V, M> {
426 // This is an entry that holds the given key:
427 FoundExisting(FullBucket<K, V, M>),
429 // There was no such entry. The reference is given back:
433 impl<K, V, M> SearchResult<K, V, M> {
434 fn into_option(self) -> Option<FullBucket<K, V, M>> {
436 FoundExisting(bucket) => Some(bucket),
442 impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> {
443 fn make_hash<Sized? X: Hash<S>>(&self, x: &X) -> SafeHash {
444 table::make_hash(&self.hasher, x)
448 fn search_equiv<'a, Sized? Q: Hash<S> + Equiv<K>>(&'a self, q: &Q)
449 -> Option<FullBucketImm<'a, K, V>> {
450 let hash = self.make_hash(q);
451 search_hashed(&self.table, hash, |k| q.equiv(k)).into_option()
455 fn search_equiv_mut<'a, Sized? Q: Hash<S> + Equiv<K>>(&'a mut self, q: &Q)
456 -> Option<FullBucketMut<'a, K, V>> {
457 let hash = self.make_hash(q);
458 search_hashed(&mut self.table, hash, |k| q.equiv(k)).into_option()
461 /// Search for a key, yielding the index if it's found in the hashtable.
462 /// If you already have the hash for the key lying around, use
464 fn search<'a, Sized? Q>(&'a self, q: &Q) -> Option<FullBucketImm<'a, K, V>>
465 where Q: BorrowFrom<K> + Eq + Hash<S>
467 let hash = self.make_hash(q);
468 search_hashed(&self.table, hash, |k| q.eq(BorrowFrom::borrow_from(k)))
472 fn search_mut<'a, Sized? Q>(&'a mut self, q: &Q) -> Option<FullBucketMut<'a, K, V>>
473 where Q: BorrowFrom<K> + Eq + Hash<S>
475 let hash = self.make_hash(q);
476 search_hashed(&mut self.table, hash, |k| q.eq(BorrowFrom::borrow_from(k)))
480 // The caller should ensure that invariants by Robin Hood Hashing hold.
481 fn insert_hashed_ordered(&mut self, hash: SafeHash, k: K, v: V) {
482 let cap = self.table.capacity();
483 let mut buckets = Bucket::new(&mut self.table, hash);
484 let ib = buckets.index();
486 while buckets.index() != ib + cap {
487 // We don't need to compare hashes for value swap.
488 // Not even DIBs for Robin Hood.
489 buckets = match buckets.peek() {
491 empty.put(hash, k, v);
494 Full(b) => b.into_bucket()
498 panic!("Internal HashMap error: Out of space.");
502 impl<K: Hash + Eq, V> HashMap<K, V, RandomSipHasher> {
503 /// Create an empty HashMap.
508 /// use std::collections::HashMap;
509 /// let mut map: HashMap<&str, int> = HashMap::new();
513 pub fn new() -> HashMap<K, V, RandomSipHasher> {
514 let hasher = RandomSipHasher::new();
515 HashMap::with_hasher(hasher)
518 /// Creates an empty hash map with the given initial capacity.
523 /// use std::collections::HashMap;
524 /// let mut map: HashMap<&str, int> = HashMap::with_capacity(10);
528 pub fn with_capacity(capacity: uint) -> HashMap<K, V, RandomSipHasher> {
529 let hasher = RandomSipHasher::new();
530 HashMap::with_capacity_and_hasher(capacity, hasher)
534 impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> {
535 /// Creates an empty hashmap which will use the given hasher to hash keys.
537 /// The creates map has the default initial capacity.
542 /// use std::collections::HashMap;
543 /// use std::hash::sip::SipHasher;
545 /// let h = SipHasher::new();
546 /// let mut map = HashMap::with_hasher(h);
547 /// map.insert(1i, 2u);
550 #[unstable = "hasher stuff is unclear"]
551 pub fn with_hasher(hasher: H) -> HashMap<K, V, H> {
554 resize_policy: DefaultResizePolicy::new(),
555 table: RawTable::new(0),
559 /// Create an empty HashMap with space for at least `capacity`
560 /// elements, using `hasher` to hash the keys.
562 /// Warning: `hasher` is normally randomly generated, and
563 /// is designed to allow HashMaps to be resistant to attacks that
564 /// cause many collisions and very poor performance. Setting it
565 /// manually using this function can expose a DoS attack vector.
570 /// use std::collections::HashMap;
571 /// use std::hash::sip::SipHasher;
573 /// let h = SipHasher::new();
574 /// let mut map = HashMap::with_capacity_and_hasher(10, h);
575 /// map.insert(1i, 2u);
578 #[unstable = "hasher stuff is unclear"]
579 pub fn with_capacity_and_hasher(capacity: uint, hasher: H) -> HashMap<K, V, H> {
580 let resize_policy = DefaultResizePolicy::new();
581 let min_cap = max(INITIAL_CAPACITY, resize_policy.min_capacity(capacity));
582 let internal_cap = min_cap.checked_next_power_of_two().expect("capacity overflow");
583 assert!(internal_cap >= capacity, "capacity overflow");
586 resize_policy: resize_policy,
587 table: RawTable::new(internal_cap),
591 /// Returns the number of elements the map can hold without reallocating.
596 /// use std::collections::HashMap;
597 /// let map: HashMap<int, int> = HashMap::with_capacity(100);
598 /// assert!(map.capacity() >= 100);
602 pub fn capacity(&self) -> uint {
603 self.resize_policy.usable_capacity(self.table.capacity())
606 /// Reserves capacity for at least `additional` more elements to be inserted
607 /// in the `HashMap`. The collection may reserve more space to avoid
608 /// frequent reallocations.
612 /// Panics if the new allocation size overflows `uint`.
617 /// use std::collections::HashMap;
618 /// let mut map: HashMap<&str, int> = HashMap::new();
622 pub fn reserve(&mut self, additional: uint) {
623 let new_size = self.len().checked_add(additional).expect("capacity overflow");
624 let min_cap = self.resize_policy.min_capacity(new_size);
626 // An invalid value shouldn't make us run out of space. This includes
627 // an overflow check.
628 assert!(new_size <= min_cap);
630 if self.table.capacity() < min_cap {
631 let new_capacity = max(min_cap.next_power_of_two(), INITIAL_CAPACITY);
632 self.resize(new_capacity);
636 /// Resizes the internal vectors to a new capacity. It's your responsibility to:
637 /// 1) Make sure the new capacity is enough for all the elements, accounting
638 /// for the load factor.
639 /// 2) Ensure new_capacity is a power of two or zero.
640 fn resize(&mut self, new_capacity: uint) {
641 assert!(self.table.size() <= new_capacity);
642 assert!(new_capacity.is_power_of_two() || new_capacity == 0);
644 let mut old_table = replace(&mut self.table, RawTable::new(new_capacity));
645 let old_size = old_table.size();
647 if old_table.capacity() == 0 || old_table.size() == 0 {
652 // Specialization of the other branch.
653 let mut bucket = Bucket::first(&mut old_table);
655 // "So a few of the first shall be last: for many be called,
658 // We'll most likely encounter a few buckets at the beginning that
659 // have their initial buckets near the end of the table. They were
660 // placed at the beginning as the probe wrapped around the table
661 // during insertion. We must skip forward to a bucket that won't
662 // get reinserted too early and won't unfairly steal others spot.
663 // This eliminates the need for robin hood.
665 bucket = match bucket.peek() {
667 if full.distance() == 0 {
668 // This bucket occupies its ideal spot.
669 // It indicates the start of another "cluster".
670 bucket = full.into_bucket();
673 // Leaving this bucket in the last cluster for later.
677 // Encountered a hole between clusters.
684 // This is how the buckets might be laid out in memory:
685 // ($ marks an initialized bucket)
687 // |$$$_$$$$$$_$$$$$|
689 // But we've skipped the entire initial cluster of buckets
690 // and will continue iteration in this order:
693 // ^ wrap around once end is reached
696 // ^ exit once table.size == 0
698 bucket = match bucket.peek() {
700 let h = bucket.hash();
701 let (b, k, v) = bucket.take();
702 self.insert_hashed_ordered(h, k, v);
704 let t = b.table(); // FIXME "lifetime too short".
705 if t.size() == 0 { break }
709 Empty(b) => b.into_bucket()
714 assert_eq!(self.table.size(), old_size);
717 /// Shrinks the capacity of the map as much as possible. It will drop
718 /// down as much as possible while maintaining the internal rules
719 /// and possibly leaving some space in accordance with the resize policy.
724 /// use std::collections::HashMap;
726 /// let mut map: HashMap<int, int> = HashMap::with_capacity(100);
727 /// map.insert(1, 2);
728 /// map.insert(3, 4);
729 /// assert!(map.capacity() >= 100);
730 /// map.shrink_to_fit();
731 /// assert!(map.capacity() >= 2);
734 pub fn shrink_to_fit(&mut self) {
735 let min_capacity = self.resize_policy.min_capacity(self.len());
736 let min_capacity = max(min_capacity.next_power_of_two(), INITIAL_CAPACITY);
738 // An invalid value shouldn't make us run out of space.
739 debug_assert!(self.len() <= min_capacity);
741 if self.table.capacity() != min_capacity {
742 let old_table = replace(&mut self.table, RawTable::new(min_capacity));
743 let old_size = old_table.size();
745 // Shrink the table. Naive algorithm for resizing:
746 for (h, k, v) in old_table.into_iter() {
747 self.insert_hashed_nocheck(h, k, v);
750 debug_assert_eq!(self.table.size(), old_size);
754 /// Insert a pre-hashed key-value pair, without first checking
755 /// that there's enough room in the buckets. Returns a reference to the
756 /// newly insert value.
758 /// If the key already exists, the hashtable will be returned untouched
759 /// and a reference to the existing element will be returned.
760 fn insert_hashed_nocheck(&mut self, hash: SafeHash, k: K, v: V) -> &mut V {
761 self.insert_or_replace_with(hash, k, v, |_, _, _| ())
764 fn insert_or_replace_with<'a, F>(&'a mut self,
768 mut found_existing: F)
770 F: FnMut(&mut K, &mut V, V),
772 // Worst case, we'll find one empty bucket among `size + 1` buckets.
773 let size = self.table.size();
774 let mut probe = Bucket::new(&mut self.table, hash);
775 let ib = probe.index();
778 let mut bucket = match probe.peek() {
781 return bucket.put(hash, k, v).into_mut_refs().1;
783 Full(bucket) => bucket
787 if bucket.hash() == hash {
789 if k == *bucket.read_mut().0 {
790 let (bucket_k, bucket_v) = bucket.into_mut_refs();
791 debug_assert!(k == *bucket_k);
792 // Key already exists. Get its reference.
793 found_existing(bucket_k, bucket_v, v);
798 let robin_ib = bucket.index() as int - bucket.distance() as int;
800 if (ib as int) < robin_ib {
801 // Found a luckier bucket than me. Better steal his spot.
802 return robin_hood(bucket, robin_ib as uint, hash, k, v);
805 probe = bucket.next();
806 assert!(probe.index() != ib + size + 1);
810 /// Deprecated: use `contains_key` and `BorrowFrom` instead.
811 #[deprecated = "use contains_key and BorrowFrom instead"]
812 pub fn contains_key_equiv<Sized? Q: Hash<S> + Equiv<K>>(&self, key: &Q) -> bool {
813 self.search_equiv(key).is_some()
816 /// Deprecated: use `get` and `BorrowFrom` instead.
817 #[deprecated = "use get and BorrowFrom instead"]
818 pub fn find_equiv<'a, Sized? Q: Hash<S> + Equiv<K>>(&'a self, k: &Q) -> Option<&'a V> {
819 self.search_equiv(k).map(|bucket| bucket.into_refs().1)
822 /// Deprecated: use `remove` and `BorrowFrom` instead.
823 #[deprecated = "use remove and BorrowFrom instead"]
824 pub fn pop_equiv<Sized? Q:Hash<S> + Equiv<K>>(&mut self, k: &Q) -> Option<V> {
825 if self.table.size() == 0 {
831 self.search_equiv_mut(k).map(|bucket| pop_internal(bucket).1)
834 /// An iterator visiting all keys in arbitrary order.
835 /// Iterator element type is `&'a K`.
840 /// use std::collections::HashMap;
842 /// let mut map = HashMap::new();
843 /// map.insert("a", 1i);
844 /// map.insert("b", 2);
845 /// map.insert("c", 3);
847 /// for key in map.keys() {
848 /// println!("{}", key);
852 pub fn keys<'a>(&'a self) -> Keys<'a, K, V> {
853 fn first<A, B>((a, _): (A, B)) -> A { a }
854 let first: fn((&'a K,&'a V)) -> &'a K = first; // coerce to fn ptr
856 Keys { inner: self.iter().map(first) }
859 /// An iterator visiting all values in arbitrary order.
860 /// Iterator element type is `&'a V`.
865 /// use std::collections::HashMap;
867 /// let mut map = HashMap::new();
868 /// map.insert("a", 1i);
869 /// map.insert("b", 2);
870 /// map.insert("c", 3);
872 /// for key in map.values() {
873 /// println!("{}", key);
877 pub fn values<'a>(&'a self) -> Values<'a, K, V> {
878 fn second<A, B>((_, b): (A, B)) -> B { b }
879 let second: fn((&'a K,&'a V)) -> &'a V = second; // coerce to fn ptr
881 Values { inner: self.iter().map(second) }
884 /// An iterator visiting all key-value pairs in arbitrary order.
885 /// Iterator element type is `(&'a K, &'a V)`.
890 /// use std::collections::HashMap;
892 /// let mut map = HashMap::new();
893 /// map.insert("a", 1i);
894 /// map.insert("b", 2);
895 /// map.insert("c", 3);
897 /// for (key, val) in map.iter() {
898 /// println!("key: {} val: {}", key, val);
902 pub fn iter(&self) -> Iter<K, V> {
903 Iter { inner: self.table.iter() }
906 /// An iterator visiting all key-value pairs in arbitrary order,
907 /// with mutable references to the values.
908 /// Iterator element type is `(&'a K, &'a mut V)`.
913 /// use std::collections::HashMap;
915 /// let mut map = HashMap::new();
916 /// map.insert("a", 1i);
917 /// map.insert("b", 2);
918 /// map.insert("c", 3);
920 /// // Update all values
921 /// for (_, val) in map.iter_mut() {
925 /// for (key, val) in map.iter() {
926 /// println!("key: {} val: {}", key, val);
930 pub fn iter_mut(&mut self) -> IterMut<K, V> {
931 IterMut { inner: self.table.iter_mut() }
934 /// Creates a consuming iterator, that is, one that moves each key-value
935 /// pair out of the map in arbitrary order. The map cannot be used after
941 /// use std::collections::HashMap;
943 /// let mut map = HashMap::new();
944 /// map.insert("a", 1i);
945 /// map.insert("b", 2);
946 /// map.insert("c", 3);
948 /// // Not possible with .iter()
949 /// let vec: Vec<(&str, int)> = map.into_iter().collect();
952 pub fn into_iter(self) -> IntoIter<K, V> {
953 fn last_two<A, B, C>((_, b, c): (A, B, C)) -> (B, C) { (b, c) }
954 let last_two: fn((SafeHash, K, V)) -> (K, V) = last_two;
957 inner: self.table.into_iter().map(last_two)
961 /// Gets the given key's corresponding entry in the map for in-place manipulation
962 pub fn entry<'a>(&'a mut self, key: K) -> Entry<'a, K, V> {
966 let hash = self.make_hash(&key);
967 search_entry_hashed(&mut self.table, hash, key)
970 /// Return the number of elements in the map.
975 /// use std::collections::HashMap;
977 /// let mut a = HashMap::new();
978 /// assert_eq!(a.len(), 0);
979 /// a.insert(1u, "a");
980 /// assert_eq!(a.len(), 1);
983 pub fn len(&self) -> uint { self.table.size() }
985 /// Return true if the map contains no elements.
990 /// use std::collections::HashMap;
992 /// let mut a = HashMap::new();
993 /// assert!(a.is_empty());
994 /// a.insert(1u, "a");
995 /// assert!(!a.is_empty());
999 pub fn is_empty(&self) -> bool { self.len() == 0 }
1001 /// Clears the map, returning all key-value pairs as an iterator. Keeps the
1002 /// allocated memory for reuse.
1007 /// use std::collections::HashMap;
1009 /// let mut a = HashMap::new();
1010 /// a.insert(1u, "a");
1011 /// a.insert(2u, "b");
1013 /// for (k, v) in a.drain().take(1) {
1014 /// assert!(k == 1 || k == 2);
1015 /// assert!(v == "a" || v == "b");
1018 /// assert!(a.is_empty());
1021 #[unstable = "matches collection reform specification, waiting for dust to settle"]
1022 pub fn drain(&mut self) -> Drain<K, V> {
1023 fn last_two<A, B, C>((_, b, c): (A, B, C)) -> (B, C) { (b, c) }
1024 let last_two: fn((SafeHash, K, V)) -> (K, V) = last_two; // coerce to fn pointer
1027 inner: self.table.drain().map(last_two),
1031 /// Clears the map, removing all key-value pairs. Keeps the allocated memory
1037 /// use std::collections::HashMap;
1039 /// let mut a = HashMap::new();
1040 /// a.insert(1u, "a");
1042 /// assert!(a.is_empty());
1046 pub fn clear(&mut self) {
1050 /// Deprecated: Renamed to `get`.
1051 #[deprecated = "Renamed to `get`"]
1052 pub fn find(&self, k: &K) -> Option<&V> {
1056 /// Returns a reference to the value corresponding to the key.
1058 /// The key may be any borrowed form of the map's key type, but
1059 /// `Hash` and `Eq` on the borrowed form *must* match those for
1065 /// use std::collections::HashMap;
1067 /// let mut map = HashMap::new();
1068 /// map.insert(1u, "a");
1069 /// assert_eq!(map.get(&1), Some(&"a"));
1070 /// assert_eq!(map.get(&2), None);
1073 pub fn get<Sized? Q>(&self, k: &Q) -> Option<&V>
1074 where Q: Hash<S> + Eq + BorrowFrom<K>
1076 self.search(k).map(|bucket| bucket.into_refs().1)
1079 /// Returns true if the map contains a value for the specified key.
1081 /// The key may be any borrowed form of the map's key type, but
1082 /// `Hash` and `Eq` on the borrowed form *must* match those for
1088 /// use std::collections::HashMap;
1090 /// let mut map = HashMap::new();
1091 /// map.insert(1u, "a");
1092 /// assert_eq!(map.contains_key(&1), true);
1093 /// assert_eq!(map.contains_key(&2), false);
1096 pub fn contains_key<Sized? Q>(&self, k: &Q) -> bool
1097 where Q: Hash<S> + Eq + BorrowFrom<K>
1099 self.search(k).is_some()
1102 /// Deprecated: Renamed to `get_mut`.
1103 #[deprecated = "Renamed to `get_mut`"]
1104 pub fn find_mut(&mut self, k: &K) -> Option<&mut V> {
1108 /// Returns a mutable reference to the value corresponding to the key.
1110 /// The key may be any borrowed form of the map's key type, but
1111 /// `Hash` and `Eq` on the borrowed form *must* match those for
1117 /// use std::collections::HashMap;
1119 /// let mut map = HashMap::new();
1120 /// map.insert(1u, "a");
1121 /// match map.get_mut(&1) {
1122 /// Some(x) => *x = "b",
1125 /// assert_eq!(map[1], "b");
1128 pub fn get_mut<Sized? Q>(&mut self, k: &Q) -> Option<&mut V>
1129 where Q: Hash<S> + Eq + BorrowFrom<K>
1131 self.search_mut(k).map(|bucket| bucket.into_mut_refs().1)
1134 /// Deprecated: Renamed to `insert`.
1135 #[deprecated = "Renamed to `insert`"]
1136 pub fn swap(&mut self, k: K, v: V) -> Option<V> {
1140 /// Inserts a key-value pair from the map. If the key already had a value
1141 /// present in the map, that value is returned. Otherwise, `None` is returned.
1146 /// use std::collections::HashMap;
1148 /// let mut map = HashMap::new();
1149 /// assert_eq!(map.insert(37u, "a"), None);
1150 /// assert_eq!(map.is_empty(), false);
1152 /// map.insert(37, "b");
1153 /// assert_eq!(map.insert(37, "c"), Some("b"));
1154 /// assert_eq!(map[37], "c");
1157 pub fn insert(&mut self, k: K, v: V) -> Option<V> {
1158 let hash = self.make_hash(&k);
1161 let mut retval = None;
1162 self.insert_or_replace_with(hash, k, v, |_, val_ref, val| {
1163 retval = Some(replace(val_ref, val));
1168 /// Deprecated: Renamed to `remove`.
1169 #[deprecated = "Renamed to `remove`"]
1170 pub fn pop(&mut self, k: &K) -> Option<V> {
1174 /// Removes a key from the map, returning the value at the key if the key
1175 /// was previously in the map.
1177 /// The key may be any borrowed form of the map's key type, but
1178 /// `Hash` and `Eq` on the borrowed form *must* match those for
1184 /// use std::collections::HashMap;
1186 /// let mut map = HashMap::new();
1187 /// map.insert(1u, "a");
1188 /// assert_eq!(map.remove(&1), Some("a"));
1189 /// assert_eq!(map.remove(&1), None);
1192 pub fn remove<Sized? Q>(&mut self, k: &Q) -> Option<V>
1193 where Q: Hash<S> + Eq + BorrowFrom<K>
1195 if self.table.size() == 0 {
1199 self.search_mut(k).map(|bucket| pop_internal(bucket).1)
1203 fn search_entry_hashed<'a, K: Eq, V>(table: &'a mut RawTable<K,V>, hash: SafeHash, k: K)
1204 -> Entry<'a, K, V> {
1205 // Worst case, we'll find one empty bucket among `size + 1` buckets.
1206 let size = table.size();
1207 let mut probe = Bucket::new(table, hash);
1208 let ib = probe.index();
1211 let bucket = match probe.peek() {
1214 return Vacant(VacantEntry {
1217 elem: NoElem(bucket),
1220 Full(bucket) => bucket
1224 if bucket.hash() == hash {
1226 if k == *bucket.read().0 {
1227 return Occupied(OccupiedEntry{
1233 let robin_ib = bucket.index() as int - bucket.distance() as int;
1235 if (ib as int) < robin_ib {
1236 // Found a luckier bucket than me. Better steal his spot.
1237 return Vacant(VacantEntry {
1240 elem: NeqElem(bucket, robin_ib as uint),
1244 probe = bucket.next();
1245 assert!(probe.index() != ib + size + 1);
1249 impl<K: Eq + Hash<S>, V: Clone, S, H: Hasher<S>> HashMap<K, V, H> {
1250 /// Deprecated: Use `map.get(k).cloned()`.
1252 /// Return a copy of the value corresponding to the key.
1253 #[deprecated = "Use `map.get(k).cloned()`"]
1254 pub fn find_copy(&self, k: &K) -> Option<V> {
1255 self.get(k).cloned()
1258 /// Deprecated: Use `map[k].clone()`.
1260 /// Return a copy of the value corresponding to the key.
1261 #[deprecated = "Use `map[k].clone()`"]
1262 pub fn get_copy(&self, k: &K) -> V {
1268 impl<K: Eq + Hash<S>, V: PartialEq, S, H: Hasher<S>> PartialEq for HashMap<K, V, H> {
1269 fn eq(&self, other: &HashMap<K, V, H>) -> bool {
1270 if self.len() != other.len() { return false; }
1272 self.iter().all(|(key, value)|
1273 other.get(key).map_or(false, |v| *value == *v)
1279 impl<K: Eq + Hash<S>, V: Eq, S, H: Hasher<S>> Eq for HashMap<K, V, H> {}
1282 impl<K: Eq + Hash<S> + Show, V: Show, S, H: Hasher<S>> Show for HashMap<K, V, H> {
1283 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1284 try!(write!(f, "{{"));
1286 for (i, (k, v)) in self.iter().enumerate() {
1287 if i != 0 { try!(write!(f, ", ")); }
1288 try!(write!(f, "{}: {}", *k, *v));
1296 impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> Default for HashMap<K, V, H> {
1298 fn default() -> HashMap<K, V, H> {
1299 HashMap::with_hasher(Default::default())
1303 // NOTE(stage0): remove impl after a snapshot
1306 impl<K: Hash<S> + Eq, Sized? Q, V, S, H: Hasher<S>> Index<Q, V> for HashMap<K, V, H>
1307 where Q: BorrowFrom<K> + Hash<S> + Eq
1310 fn index<'a>(&'a self, index: &Q) -> &'a V {
1311 self.get(index).expect("no entry found for key")
1315 #[cfg(not(stage0))] // NOTE(stage0): remove cfg after a snapshot
1317 impl<K: Hash<S> + Eq, Sized? Q, V, S, H: Hasher<S>> Index<Q> for HashMap<K, V, H>
1318 where Q: BorrowFrom<K> + Hash<S> + Eq
1323 fn index<'a>(&'a self, index: &Q) -> &'a V {
1324 self.get(index).expect("no entry found for key")
1328 // NOTE(stage0): remove impl after a snapshot
1331 impl<K: Hash<S> + Eq, Sized? Q, V, S, H: Hasher<S>> IndexMut<Q, V> for HashMap<K, V, H>
1332 where Q: BorrowFrom<K> + Hash<S> + Eq
1335 fn index_mut<'a>(&'a mut self, index: &Q) -> &'a mut V {
1336 self.get_mut(index).expect("no entry found for key")
1340 #[cfg(not(stage0))] // NOTE(stage0): remove cfg after a snapshot
1342 impl<K: Hash<S> + Eq, Sized? Q, V, S, H: Hasher<S>> IndexMut<Q> for HashMap<K, V, H>
1343 where Q: BorrowFrom<K> + Hash<S> + Eq
1348 fn index_mut<'a>(&'a mut self, index: &Q) -> &'a mut V {
1349 self.get_mut(index).expect("no entry found for key")
1353 /// HashMap iterator
1355 pub struct Iter<'a, K: 'a, V: 'a> {
1356 inner: table::Iter<'a, K, V>
1359 // FIXME(#19839) Remove in favor of `#[deriving(Clone)]`
1360 impl<'a, K, V> Clone for Iter<'a, K, V> {
1361 fn clone(&self) -> Iter<'a, K, V> {
1363 inner: self.inner.clone()
1368 /// HashMap mutable values iterator
1370 pub struct IterMut<'a, K: 'a, V: 'a> {
1371 inner: table::IterMut<'a, K, V>
1374 /// HashMap move iterator
1376 pub struct IntoIter<K, V> {
1380 table::IntoIter<K, V>,
1381 fn((SafeHash, K, V)) -> (K, V),
1385 /// HashMap keys iterator
1387 pub struct Keys<'a, K: 'a, V: 'a> {
1388 inner: Map<(&'a K, &'a V), &'a K, Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a K>
1391 // FIXME(#19839) Remove in favor of `#[deriving(Clone)]`
1392 impl<'a, K, V> Clone for Keys<'a, K, V> {
1393 fn clone(&self) -> Keys<'a, K, V> {
1395 inner: self.inner.clone()
1400 /// HashMap values iterator
1402 pub struct Values<'a, K: 'a, V: 'a> {
1403 inner: Map<(&'a K, &'a V), &'a V, Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a V>
1406 // FIXME(#19839) Remove in favor of `#[deriving(Clone)]`
1407 impl<'a, K, V> Clone for Values<'a, K, V> {
1408 fn clone(&self) -> Values<'a, K, V> {
1410 inner: self.inner.clone()
1415 /// HashMap drain iterator
1416 #[unstable = "matches collection reform specification, waiting for dust to settle"]
1417 pub struct Drain<'a, K: 'a, V: 'a> {
1421 table::Drain<'a, K, V>,
1422 fn((SafeHash, K, V)) -> (K, V),
1426 /// A view into a single occupied location in a HashMap
1427 pub struct OccupiedEntry<'a, K:'a, V:'a> {
1428 elem: FullBucket<K, V, &'a mut RawTable<K, V>>,
1431 /// A view into a single empty location in a HashMap
1432 pub struct VacantEntry<'a, K:'a, V:'a> {
1435 elem: VacantEntryState<K,V, &'a mut RawTable<K, V>>,
1438 /// A view into a single location in a map, which may be vacant or occupied
1439 pub enum Entry<'a, K:'a, V:'a> {
1440 /// An occupied Entry
1441 Occupied(OccupiedEntry<'a, K, V>),
1443 Vacant(VacantEntry<'a, K, V>),
1446 /// Possible states of a VacantEntry
1447 enum VacantEntryState<K, V, M> {
1448 /// The index is occupied, but the key to insert has precedence,
1449 /// and will kick the current one out on insertion
1450 NeqElem(FullBucket<K, V, M>, uint),
1451 /// The index is genuinely vacant
1452 NoElem(EmptyBucket<K, V, M>),
1456 impl<'a, K, V> Iterator for Iter<'a, K, V> {
1457 type Item = (&'a K, &'a V);
1459 #[inline] fn next(&mut self) -> Option<(&'a K, &'a V)> { self.inner.next() }
1460 #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
1464 impl<'a, K, V> Iterator for IterMut<'a, K, V> {
1465 type Item = (&'a K, &'a mut V);
1467 #[inline] fn next(&mut self) -> Option<(&'a K, &'a mut V)> { self.inner.next() }
1468 #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
1472 impl<K, V> Iterator for IntoIter<K, V> {
1475 #[inline] fn next(&mut self) -> Option<(K, V)> { self.inner.next() }
1476 #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
1480 impl<'a, K, V> Iterator for Keys<'a, K, V> {
1483 #[inline] fn next(&mut self) -> Option<(&'a K)> { self.inner.next() }
1484 #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
1488 impl<'a, K, V> Iterator for Values<'a, K, V> {
1491 #[inline] fn next(&mut self) -> Option<(&'a V)> { self.inner.next() }
1492 #[inline] fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
1496 impl<'a, K: 'a, V: 'a> Iterator for Drain<'a, K, V> {
1500 fn next(&mut self) -> Option<(K, V)> {
1504 fn size_hint(&self) -> (uint, Option<uint>) {
1505 self.inner.size_hint()
1509 impl<'a, K, V> OccupiedEntry<'a, K, V> {
1510 /// Gets a reference to the value in the entry
1511 pub fn get(&self) -> &V {
1515 /// Gets a mutable reference to the value in the entry
1516 pub fn get_mut(&mut self) -> &mut V {
1517 self.elem.read_mut().1
1520 /// Converts the OccupiedEntry into a mutable reference to the value in the entry
1521 /// with a lifetime bound to the map itself
1522 pub fn into_mut(self) -> &'a mut V {
1523 self.elem.into_mut_refs().1
1526 /// Sets the value of the entry, and returns the entry's old value
1527 pub fn set(&mut self, mut value: V) -> V {
1528 let old_value = self.get_mut();
1529 mem::swap(&mut value, old_value);
1533 /// Takes the value out of the entry, and returns it
1534 pub fn take(self) -> V {
1535 pop_internal(self.elem).1
1539 impl<'a, K, V> VacantEntry<'a, K, V> {
1540 /// Sets the value of the entry with the VacantEntry's key,
1541 /// and returns a mutable reference to it
1542 pub fn set(self, value: V) -> &'a mut V {
1544 NeqElem(bucket, ib) => {
1545 robin_hood(bucket, ib, self.hash, self.key, value)
1548 bucket.put(self.hash, self.key, value).into_mut_refs().1
1555 impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> FromIterator<(K, V)> for HashMap<K, V, H> {
1556 fn from_iter<T: Iterator<Item=(K, V)>>(iter: T) -> HashMap<K, V, H> {
1557 let lower = iter.size_hint().0;
1558 let mut map = HashMap::with_capacity_and_hasher(lower, Default::default());
1565 impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> Extend<(K, V)> for HashMap<K, V, H> {
1566 fn extend<T: Iterator<Item=(K, V)>>(&mut self, mut iter: T) {
1567 for (k, v) in iter {
1579 use super::Entry::{Occupied, Vacant};
1581 use iter::{range_inclusive, range_step_inclusive};
1583 use rand::{weak_rng, Rng};
1585 struct KindaIntLike(int);
1587 #[allow(deprecated)]
1588 impl Equiv<int> for KindaIntLike {
1589 fn equiv(&self, other: &int) -> bool {
1590 let KindaIntLike(this) = *self;
1594 impl<S: hash::Writer> hash::Hash<S> for KindaIntLike {
1595 fn hash(&self, state: &mut S) {
1596 let KindaIntLike(this) = *self;
1602 fn test_create_capacity_zero() {
1603 let mut m = HashMap::with_capacity(0);
1605 assert!(m.insert(1i, 1i).is_none());
1607 assert!(m.contains_key(&1));
1608 assert!(!m.contains_key(&0));
1613 let mut m = HashMap::new();
1614 assert_eq!(m.len(), 0);
1615 assert!(m.insert(1i, 2i).is_none());
1616 assert_eq!(m.len(), 1);
1617 assert!(m.insert(2i, 4i).is_none());
1618 assert_eq!(m.len(), 2);
1619 assert_eq!(*m.get(&1).unwrap(), 2);
1620 assert_eq!(*m.get(&2).unwrap(), 4);
1623 thread_local! { static DROP_VECTOR: RefCell<Vec<int>> = RefCell::new(Vec::new()) }
1625 #[deriving(Hash, PartialEq, Eq)]
1631 fn new(k: uint) -> Dropable {
1632 DROP_VECTOR.with(|slot| {
1633 slot.borrow_mut()[k] += 1;
1640 impl Drop for Dropable {
1641 fn drop(&mut self) {
1642 DROP_VECTOR.with(|slot| {
1643 slot.borrow_mut()[self.k] -= 1;
1648 impl Clone for Dropable {
1649 fn clone(&self) -> Dropable {
1650 Dropable::new(self.k)
1656 DROP_VECTOR.with(|slot| {
1657 *slot.borrow_mut() = Vec::from_elem(200, 0i);
1661 let mut m = HashMap::new();
1663 DROP_VECTOR.with(|v| {
1664 for i in range(0u, 200) {
1665 assert_eq!(v.borrow()[i], 0);
1669 for i in range(0u, 100) {
1670 let d1 = Dropable::new(i);
1671 let d2 = Dropable::new(i+100);
1675 DROP_VECTOR.with(|v| {
1676 for i in range(0u, 200) {
1677 assert_eq!(v.borrow()[i], 1);
1681 for i in range(0u, 50) {
1682 let k = Dropable::new(i);
1683 let v = m.remove(&k);
1685 assert!(v.is_some());
1687 DROP_VECTOR.with(|v| {
1688 assert_eq!(v.borrow()[i], 1);
1689 assert_eq!(v.borrow()[i+100], 1);
1693 DROP_VECTOR.with(|v| {
1694 for i in range(0u, 50) {
1695 assert_eq!(v.borrow()[i], 0);
1696 assert_eq!(v.borrow()[i+100], 0);
1699 for i in range(50u, 100) {
1700 assert_eq!(v.borrow()[i], 1);
1701 assert_eq!(v.borrow()[i+100], 1);
1706 DROP_VECTOR.with(|v| {
1707 for i in range(0u, 200) {
1708 assert_eq!(v.borrow()[i], 0);
1714 fn test_move_iter_drops() {
1715 DROP_VECTOR.with(|v| {
1716 *v.borrow_mut() = Vec::from_elem(200, 0i);
1720 let mut hm = HashMap::new();
1722 DROP_VECTOR.with(|v| {
1723 for i in range(0u, 200) {
1724 assert_eq!(v.borrow()[i], 0);
1728 for i in range(0u, 100) {
1729 let d1 = Dropable::new(i);
1730 let d2 = Dropable::new(i+100);
1734 DROP_VECTOR.with(|v| {
1735 for i in range(0u, 200) {
1736 assert_eq!(v.borrow()[i], 1);
1743 // By the way, ensure that cloning doesn't screw up the dropping.
1747 let mut half = hm.into_iter().take(50);
1749 DROP_VECTOR.with(|v| {
1750 for i in range(0u, 200) {
1751 assert_eq!(v.borrow()[i], 1);
1757 DROP_VECTOR.with(|v| {
1758 let nk = range(0u, 100).filter(|&i| {
1762 let nv = range(0u, 100).filter(|&i| {
1763 v.borrow()[i+100] == 1
1771 DROP_VECTOR.with(|v| {
1772 for i in range(0u, 200) {
1773 assert_eq!(v.borrow()[i], 0);
1779 fn test_empty_pop() {
1780 let mut m: HashMap<int, bool> = HashMap::new();
1781 assert_eq!(m.remove(&0), None);
1785 fn test_lots_of_insertions() {
1786 let mut m = HashMap::new();
1788 // Try this a few times to make sure we never screw up the hashmap's
1790 for _ in range(0i, 10) {
1791 assert!(m.is_empty());
1793 for i in range_inclusive(1i, 1000) {
1794 assert!(m.insert(i, i).is_none());
1796 for j in range_inclusive(1, i) {
1798 assert_eq!(r, Some(&j));
1801 for j in range_inclusive(i+1, 1000) {
1803 assert_eq!(r, None);
1807 for i in range_inclusive(1001i, 2000) {
1808 assert!(!m.contains_key(&i));
1812 for i in range_inclusive(1i, 1000) {
1813 assert!(m.remove(&i).is_some());
1815 for j in range_inclusive(1, i) {
1816 assert!(!m.contains_key(&j));
1819 for j in range_inclusive(i+1, 1000) {
1820 assert!(m.contains_key(&j));
1824 for i in range_inclusive(1i, 1000) {
1825 assert!(!m.contains_key(&i));
1828 for i in range_inclusive(1i, 1000) {
1829 assert!(m.insert(i, i).is_none());
1833 for i in range_step_inclusive(1000i, 1, -1) {
1834 assert!(m.remove(&i).is_some());
1836 for j in range_inclusive(i, 1000) {
1837 assert!(!m.contains_key(&j));
1840 for j in range_inclusive(1, i-1) {
1841 assert!(m.contains_key(&j));
1848 fn test_find_mut() {
1849 let mut m = HashMap::new();
1850 assert!(m.insert(1i, 12i).is_none());
1851 assert!(m.insert(2i, 8i).is_none());
1852 assert!(m.insert(5i, 14i).is_none());
1854 match m.get_mut(&5) {
1855 None => panic!(), Some(x) => *x = new
1857 assert_eq!(m.get(&5), Some(&new));
1861 fn test_insert_overwrite() {
1862 let mut m = HashMap::new();
1863 assert!(m.insert(1i, 2i).is_none());
1864 assert_eq!(*m.get(&1).unwrap(), 2);
1865 assert!(!m.insert(1i, 3i).is_none());
1866 assert_eq!(*m.get(&1).unwrap(), 3);
1870 fn test_insert_conflicts() {
1871 let mut m = HashMap::with_capacity(4);
1872 assert!(m.insert(1i, 2i).is_none());
1873 assert!(m.insert(5i, 3i).is_none());
1874 assert!(m.insert(9i, 4i).is_none());
1875 assert_eq!(*m.get(&9).unwrap(), 4);
1876 assert_eq!(*m.get(&5).unwrap(), 3);
1877 assert_eq!(*m.get(&1).unwrap(), 2);
1881 fn test_conflict_remove() {
1882 let mut m = HashMap::with_capacity(4);
1883 assert!(m.insert(1i, 2i).is_none());
1884 assert_eq!(*m.get(&1).unwrap(), 2);
1885 assert!(m.insert(5, 3).is_none());
1886 assert_eq!(*m.get(&1).unwrap(), 2);
1887 assert_eq!(*m.get(&5).unwrap(), 3);
1888 assert!(m.insert(9, 4).is_none());
1889 assert_eq!(*m.get(&1).unwrap(), 2);
1890 assert_eq!(*m.get(&5).unwrap(), 3);
1891 assert_eq!(*m.get(&9).unwrap(), 4);
1892 assert!(m.remove(&1).is_some());
1893 assert_eq!(*m.get(&9).unwrap(), 4);
1894 assert_eq!(*m.get(&5).unwrap(), 3);
1898 fn test_is_empty() {
1899 let mut m = HashMap::with_capacity(4);
1900 assert!(m.insert(1i, 2i).is_none());
1901 assert!(!m.is_empty());
1902 assert!(m.remove(&1).is_some());
1903 assert!(m.is_empty());
1908 let mut m = HashMap::new();
1910 assert_eq!(m.remove(&1), Some(2));
1911 assert_eq!(m.remove(&1), None);
1915 #[allow(deprecated)]
1916 fn test_pop_equiv() {
1917 let mut m = HashMap::new();
1919 assert_eq!(m.pop_equiv(&KindaIntLike(1)), Some(2));
1920 assert_eq!(m.pop_equiv(&KindaIntLike(1)), None);
1925 let mut m = HashMap::with_capacity(4);
1926 for i in range(0u, 32) {
1927 assert!(m.insert(i, i*2).is_none());
1929 assert_eq!(m.len(), 32);
1931 let mut observed: u32 = 0;
1933 for (k, v) in m.iter() {
1934 assert_eq!(*v, *k * 2);
1935 observed |= 1 << *k;
1937 assert_eq!(observed, 0xFFFF_FFFF);
1942 let vec = vec![(1i, 'a'), (2i, 'b'), (3i, 'c')];
1943 let map = vec.into_iter().collect::<HashMap<int, char>>();
1944 let keys = map.keys().map(|&k| k).collect::<Vec<int>>();
1945 assert_eq!(keys.len(), 3);
1946 assert!(keys.contains(&1));
1947 assert!(keys.contains(&2));
1948 assert!(keys.contains(&3));
1953 let vec = vec![(1i, 'a'), (2i, 'b'), (3i, 'c')];
1954 let map = vec.into_iter().collect::<HashMap<int, char>>();
1955 let values = map.values().map(|&v| v).collect::<Vec<char>>();
1956 assert_eq!(values.len(), 3);
1957 assert!(values.contains(&'a'));
1958 assert!(values.contains(&'b'));
1959 assert!(values.contains(&'c'));
1964 let mut m = HashMap::new();
1965 assert!(m.get(&1i).is_none());
1969 Some(v) => assert_eq!(*v, 2)
1974 #[allow(deprecated)]
1975 fn test_find_copy() {
1976 let mut m = HashMap::new();
1977 assert!(m.get(&1i).is_none());
1979 for i in range(1i, 10000) {
1981 match m.find_copy(&i) {
1983 Some(v) => assert_eq!(v, i + 7)
1985 for j in range(1i, i/100) {
1986 match m.find_copy(&j) {
1988 Some(v) => assert_eq!(v, j + 7)
1996 let mut m1 = HashMap::new();
2001 let mut m2 = HashMap::new();
2014 let mut map: HashMap<int, int> = HashMap::new();
2015 let empty: HashMap<int, int> = HashMap::new();
2020 let map_str = format!("{}", map);
2022 assert!(map_str == "{1: 2, 3: 4}" || map_str == "{3: 4, 1: 2}");
2023 assert_eq!(format!("{}", empty), "{}");
2028 let mut m = HashMap::new();
2030 assert_eq!(m.len(), 0);
2031 assert!(m.is_empty());
2034 let old_cap = m.table.capacity();
2035 while old_cap == m.table.capacity() {
2040 assert_eq!(m.len(), i);
2041 assert!(!m.is_empty());
2045 fn test_behavior_resize_policy() {
2046 let mut m = HashMap::new();
2048 assert_eq!(m.len(), 0);
2049 assert_eq!(m.table.capacity(), 0);
2050 assert!(m.is_empty());
2054 assert!(m.is_empty());
2055 let initial_cap = m.table.capacity();
2056 m.reserve(initial_cap);
2057 let cap = m.table.capacity();
2059 assert_eq!(cap, initial_cap * 2);
2062 for _ in range(0, cap * 3 / 4) {
2066 // three quarters full
2068 assert_eq!(m.len(), i);
2069 assert_eq!(m.table.capacity(), cap);
2071 for _ in range(0, cap / 4) {
2077 let new_cap = m.table.capacity();
2078 assert_eq!(new_cap, cap * 2);
2080 for _ in range(0, cap / 2 - 1) {
2083 assert_eq!(m.table.capacity(), new_cap);
2085 // A little more than one quarter full.
2087 assert_eq!(m.table.capacity(), cap);
2088 // again, a little more than half full
2089 for _ in range(0, cap / 2 - 1) {
2095 assert_eq!(m.len(), i);
2096 assert!(!m.is_empty());
2097 assert_eq!(m.table.capacity(), initial_cap);
2101 fn test_reserve_shrink_to_fit() {
2102 let mut m = HashMap::new();
2105 assert!(m.capacity() >= m.len());
2106 for i in range(0, 128) {
2111 let usable_cap = m.capacity();
2112 for i in range(128, 128+256) {
2114 assert_eq!(m.capacity(), usable_cap);
2117 for i in range(100, 128+256) {
2118 assert_eq!(m.remove(&i), Some(i));
2122 assert_eq!(m.len(), 100);
2123 assert!(!m.is_empty());
2124 assert!(m.capacity() >= m.len());
2126 for i in range(0, 100) {
2127 assert_eq!(m.remove(&i), Some(i));
2132 assert_eq!(m.len(), 1);
2133 assert!(m.capacity() >= m.len());
2134 assert_eq!(m.remove(&0), Some(0));
2138 fn test_find_equiv() {
2139 let mut m = HashMap::new();
2141 let (foo, bar, baz) = (1i,2i,3i);
2142 m.insert("foo".to_string(), foo);
2143 m.insert("bar".to_string(), bar);
2144 m.insert("baz".to_string(), baz);
2147 assert_eq!(m.get("foo"), Some(&foo));
2148 assert_eq!(m.get("bar"), Some(&bar));
2149 assert_eq!(m.get("baz"), Some(&baz));
2151 assert_eq!(m.get("qux"), None);
2155 fn test_from_iter() {
2156 let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
2158 let map: HashMap<int, int> = xs.iter().map(|&x| x).collect();
2160 for &(k, v) in xs.iter() {
2161 assert_eq!(map.get(&k), Some(&v));
2166 fn test_size_hint() {
2167 let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
2169 let map: HashMap<int, int> = xs.iter().map(|&x| x).collect();
2171 let mut iter = map.iter();
2173 for _ in iter.by_ref().take(3) {}
2175 assert_eq!(iter.size_hint(), (3, Some(3)));
2179 fn test_mut_size_hint() {
2180 let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
2182 let mut map: HashMap<int, int> = xs.iter().map(|&x| x).collect();
2184 let mut iter = map.iter_mut();
2186 for _ in iter.by_ref().take(3) {}
2188 assert_eq!(iter.size_hint(), (3, Some(3)));
2193 let mut map: HashMap<int, int> = HashMap::new();
2199 assert_eq!(map[2], 1);
2204 fn test_index_nonexistent() {
2205 let mut map: HashMap<int, int> = HashMap::new();
2216 let xs = [(1i, 10i), (2, 20), (3, 30), (4, 40), (5, 50), (6, 60)];
2218 let mut map: HashMap<int, int> = xs.iter().map(|&x| x).collect();
2220 // Existing key (insert)
2221 match map.entry(1) {
2222 Vacant(_) => unreachable!(),
2223 Occupied(mut view) => {
2224 assert_eq!(view.get(), &10);
2225 assert_eq!(view.set(100), 10);
2228 assert_eq!(map.get(&1).unwrap(), &100);
2229 assert_eq!(map.len(), 6);
2232 // Existing key (update)
2233 match map.entry(2) {
2234 Vacant(_) => unreachable!(),
2235 Occupied(mut view) => {
2236 let v = view.get_mut();
2237 let new_v = (*v) * 10;
2241 assert_eq!(map.get(&2).unwrap(), &200);
2242 assert_eq!(map.len(), 6);
2244 // Existing key (take)
2245 match map.entry(3) {
2246 Vacant(_) => unreachable!(),
2248 assert_eq!(view.take(), 30);
2251 assert_eq!(map.get(&3), None);
2252 assert_eq!(map.len(), 5);
2255 // Inexistent key (insert)
2256 match map.entry(10) {
2257 Occupied(_) => unreachable!(),
2259 assert_eq!(*view.set(1000), 1000);
2262 assert_eq!(map.get(&10).unwrap(), &1000);
2263 assert_eq!(map.len(), 6);
2267 fn test_entry_take_doesnt_corrupt() {
2269 fn check(m: &HashMap<int, ()>) {
2271 assert!(m.contains_key(k),
2272 "{} is in keys() but not in the map?", k);
2276 let mut m = HashMap::new();
2277 let mut rng = weak_rng();
2279 // Populate the map with some items.
2280 for _ in range(0u, 50) {
2281 let x = rng.gen_range(-10, 10);
2285 for i in range(0u, 1000) {
2286 let x = rng.gen_range(-10, 10);
2290 println!("{}: remove {}", i, x);