diff options
Diffstat (limited to 'ctr-std/src/collections/hash')
| -rw-r--r-- | ctr-std/src/collections/hash/bench.rs | 128 | ||||
| -rw-r--r-- | ctr-std/src/collections/hash/map.rs | 3686 | ||||
| -rw-r--r-- | ctr-std/src/collections/hash/mod.rs | 24 | ||||
| -rw-r--r-- | ctr-std/src/collections/hash/set.rs | 1783 | ||||
| -rw-r--r-- | ctr-std/src/collections/hash/table.rs | 1133 |
5 files changed, 0 insertions, 6754 deletions
diff --git a/ctr-std/src/collections/hash/bench.rs b/ctr-std/src/collections/hash/bench.rs deleted file mode 100644 index ff6cb79..0000000 --- a/ctr-std/src/collections/hash/bench.rs +++ /dev/null @@ -1,128 +0,0 @@ -// Copyright 2014 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -#![cfg(test)] - -extern crate test; - -use self::test::Bencher; - -#[bench] -fn new_drop(b: &mut Bencher) { - use super::map::HashMap; - - b.iter(|| { - let m: HashMap<i32, i32> = HashMap::new(); - assert_eq!(m.len(), 0); - }) -} - -#[bench] -fn new_insert_drop(b: &mut Bencher) { - use super::map::HashMap; - - b.iter(|| { - let mut m = HashMap::new(); - m.insert(0, 0); - assert_eq!(m.len(), 1); - }) -} - -#[bench] -fn grow_by_insertion(b: &mut Bencher) { - use super::map::HashMap; - - let mut m = HashMap::new(); - - for i in 1..1001 { - m.insert(i, i); - } - - let mut k = 1001; - - b.iter(|| { - m.insert(k, k); - k += 1; - }); -} - -#[bench] -fn find_existing(b: &mut Bencher) { - use super::map::HashMap; - - let mut m = HashMap::new(); - - for i in 1..1001 { - m.insert(i, i); - } - - b.iter(|| { - for i in 1..1001 { - m.contains_key(&i); - } - }); -} - -#[bench] -fn find_nonexisting(b: &mut Bencher) { - use super::map::HashMap; - - let mut m = HashMap::new(); - - for i in 1..1001 { - m.insert(i, i); - } - - b.iter(|| { - for i in 1001..2001 { - m.contains_key(&i); - } - }); -} - -#[bench] -fn hashmap_as_queue(b: &mut Bencher) { - use super::map::HashMap; - - let mut m = HashMap::new(); - - for i in 1..1001 { - m.insert(i, i); - } - - let mut k = 1; - - b.iter(|| { - m.remove(&k); - m.insert(k + 1000, k + 1000); - k += 1; - }); -} - -#[bench] -fn get_remove_insert(b: &mut Bencher) { - use super::map::HashMap; - - let mut m = HashMap::new(); - - for i in 1..1001 { - m.insert(i, i); - } - - let mut k = 1; - - b.iter(|| { - m.get(&(k + 400)); - m.get(&(k + 2000)); - m.remove(&k); - m.insert(k + 1000, k + 1000); - k += 1; - }) -} diff --git a/ctr-std/src/collections/hash/map.rs b/ctr-std/src/collections/hash/map.rs deleted file mode 100644 index 91912e5..0000000 --- a/ctr-std/src/collections/hash/map.rs +++ /dev/null @@ -1,3686 +0,0 @@ -// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -use self::Entry::*; -use self::VacantEntryState::*; - -use collections::CollectionAllocErr; -use cell::Cell; -use borrow::Borrow; -use cmp::max; -use fmt::{self, Debug}; -#[allow(deprecated)] -use hash::{Hash, Hasher, BuildHasher, SipHasher13}; -use iter::{FromIterator, FusedIterator}; -use mem::{self, replace}; -use ops::{Deref, Index}; -use sys; - -use super::table::{self, Bucket, EmptyBucket, Fallibility, FullBucket, FullBucketMut, RawTable, - SafeHash}; -use super::table::BucketState::{Empty, Full}; -use super::table::Fallibility::{Fallible, Infallible}; - -const MIN_NONZERO_RAW_CAPACITY: usize = 32; // must be a power of two - -/// The default behavior of HashMap implements a maximum load factor of 90.9%. -#[derive(Clone)] -struct DefaultResizePolicy; - -impl DefaultResizePolicy { - #[inline] - fn new() -> DefaultResizePolicy { - DefaultResizePolicy - } - - /// A hash map's "capacity" is the number of elements it can hold without - /// being resized. Its "raw capacity" is the number of slots required to - /// provide that capacity, accounting for maximum loading. The raw capacity - /// is always zero or a power of two. - #[inline] - fn try_raw_capacity(&self, len: usize) -> Result<usize, CollectionAllocErr> { - if len == 0 { - Ok(0) - } else { - // 1. Account for loading: `raw_capacity >= len * 1.1`. - // 2. Ensure it is a power of two. - // 3. Ensure it is at least the minimum size. - let mut raw_cap = len.checked_mul(11) - .map(|l| l / 10) - .and_then(|l| l.checked_next_power_of_two()) - .ok_or(CollectionAllocErr::CapacityOverflow)?; - - raw_cap = max(MIN_NONZERO_RAW_CAPACITY, raw_cap); - Ok(raw_cap) - } - } - - #[inline] - fn raw_capacity(&self, len: usize) -> usize { - self.try_raw_capacity(len).expect("raw_capacity overflow") - } - - /// The capacity of the given raw capacity. - #[inline] - fn capacity(&self, raw_cap: usize) -> usize { - // This doesn't have to be checked for overflow since allocation size - // in bytes will overflow earlier than multiplication by 10. - // - // As per https://github.com/rust-lang/rust/pull/30991 this is updated - // to be: (raw_cap * den + den - 1) / num - (raw_cap * 10 + 10 - 1) / 11 - } -} - -// The main performance trick in this hashmap is called Robin Hood Hashing. -// It gains its excellent performance from one essential operation: -// -// If an insertion collides with an existing element, and that element's -// "probe distance" (how far away the element is from its ideal location) -// is higher than how far we've already probed, swap the elements. -// -// This massively lowers variance in probe distance, and allows us to get very -// high load factors with good performance. The 90% load factor I use is rather -// conservative. -// -// > Why a load factor of approximately 90%? -// -// In general, all the distances to initial buckets will converge on the mean. -// At a load factor of α, the odds of finding the target bucket after k -// probes is approximately 1-α^k. If we set this equal to 50% (since we converge -// on the mean) and set k=8 (64-byte cache line / 8-byte hash), α=0.92. I round -// this down to make the math easier on the CPU and avoid its FPU. -// Since on average we start the probing in the middle of a cache line, this -// strategy pulls in two cache lines of hashes on every lookup. I think that's -// pretty good, but if you want to trade off some space, it could go down to one -// cache line on average with an α of 0.84. -// -// > Wait, what? Where did you get 1-α^k from? -// -// On the first probe, your odds of a collision with an existing element is α. -// The odds of doing this twice in a row is approximately α^2. For three times, -// α^3, etc. Therefore, the odds of colliding k times is α^k. The odds of NOT -// colliding after k tries is 1-α^k. -// -// The paper from 1986 cited below mentions an implementation which keeps track -// of the distance-to-initial-bucket histogram. This approach is not suitable -// for modern architectures because it requires maintaining an internal data -// structure. This allows very good first guesses, but we are most concerned -// with guessing entire cache lines, not individual indexes. Furthermore, array -// accesses are no longer linear and in one direction, as we have now. There -// is also memory and cache pressure that this would entail that would be very -// difficult to properly see in a microbenchmark. -// -// ## Future Improvements (FIXME!) -// -// Allow the load factor to be changed dynamically and/or at initialization. -// -// Also, would it be possible for us to reuse storage when growing the -// underlying table? This is exactly the use case for 'realloc', and may -// be worth exploring. -// -// ## Future Optimizations (FIXME!) -// -// Another possible design choice that I made without any real reason is -// parameterizing the raw table over keys and values. Technically, all we need -// is the size and alignment of keys and values, and the code should be just as -// efficient (well, we might need one for power-of-two size and one for not...). -// This has the potential to reduce code bloat in rust executables, without -// really losing anything except 4 words (key size, key alignment, val size, -// val alignment) which can be passed in to every call of a `RawTable` function. -// This would definitely be an avenue worth exploring if people start complaining -// about the size of rust executables. -// -// Annotate exceedingly likely branches in `table::make_hash` -// and `search_hashed` to reduce instruction cache pressure -// and mispredictions once it becomes possible (blocked on issue #11092). -// -// Shrinking the table could simply reallocate in place after moving buckets -// to the first half. -// -// The growth algorithm (fragment of the Proof of Correctness) -// -------------------- -// -// The growth algorithm is basically a fast path of the naive reinsertion- -// during-resize algorithm. Other paths should never be taken. -// -// Consider growing a robin hood hashtable of capacity n. Normally, we do this -// by allocating a new table of capacity `2n`, and then individually reinsert -// each element in the old table into the new one. This guarantees that the -// new table is a valid robin hood hashtable with all the desired statistical -// properties. Remark that the order we reinsert the elements in should not -// matter. For simplicity and efficiency, we will consider only linear -// reinsertions, which consist of reinserting all elements in the old table -// into the new one by increasing order of index. However we will not be -// starting our reinsertions from index 0 in general. If we start from index -// i, for the purpose of reinsertion we will consider all elements with real -// index j < i to have virtual index n + j. -// -// Our hash generation scheme consists of generating a 64-bit hash and -// truncating the most significant bits. When moving to the new table, we -// simply introduce a new bit to the front of the hash. Therefore, if an -// elements has ideal index i in the old table, it can have one of two ideal -// locations in the new table. If the new bit is 0, then the new ideal index -// is i. If the new bit is 1, then the new ideal index is n + i. Intuitively, -// we are producing two independent tables of size n, and for each element we -// independently choose which table to insert it into with equal probability. -// However the rather than wrapping around themselves on overflowing their -// indexes, the first table overflows into the first, and the first into the -// second. Visually, our new table will look something like: -// -// [yy_xxx_xxxx_xxx|xx_yyy_yyyy_yyy] -// -// Where x's are elements inserted into the first table, y's are elements -// inserted into the second, and _'s are empty sections. We now define a few -// key concepts that we will use later. Note that this is a very abstract -// perspective of the table. A real resized table would be at least half -// empty. -// -// Theorem: A linear robin hood reinsertion from the first ideal element -// produces identical results to a linear naive reinsertion from the same -// element. -// -// FIXME(Gankro, pczarn): review the proof and put it all in a separate README.md -// -// Adaptive early resizing -// ---------------------- -// To protect against degenerate performance scenarios (including DOS attacks), -// the implementation includes an adaptive behavior that can resize the map -// early (before its capacity is exceeded) when suspiciously long probe sequences -// are encountered. -// -// With this algorithm in place it would be possible to turn a CPU attack into -// a memory attack due to the aggressive resizing. To prevent that the -// adaptive behavior only triggers when the map is at least half full. -// This reduces the effectiveness of the algorithm but also makes it completely safe. -// -// The previous safety measure also prevents degenerate interactions with -// really bad quality hash algorithms that can make normal inputs look like a -// DOS attack. -// -const DISPLACEMENT_THRESHOLD: usize = 128; -// -// The threshold of 128 is chosen to minimize the chance of exceeding it. -// In particular, we want that chance to be less than 10^-8 with a load of 90%. -// For displacement, the smallest constant that fits our needs is 90, -// so we round that up to 128. -// -// At a load factor of α, the odds of finding the target bucket after exactly n -// unsuccessful probes[1] are -// -// Pr_α{displacement = n} = -// (1 - α) / α * ∑_{k≥1} e^(-kα) * (kα)^(k+n) / (k + n)! * (1 - kα / (k + n + 1)) -// -// We use this formula to find the probability of triggering the adaptive behavior -// -// Pr_0.909{displacement > 128} = 1.601 * 10^-11 -// -// 1. Alfredo Viola (2005). Distributional analysis of Robin Hood linear probing -// hashing with buckets. - -/// A hash map implemented with linear probing and Robin Hood bucket stealing. -/// -/// By default, `HashMap` uses a hashing algorithm selected to provide -/// resistance against HashDoS attacks. The algorithm is randomly seeded, and a -/// reasonable best-effort is made to generate this seed from a high quality, -/// secure source of randomness provided by the host without blocking the -/// program. Because of this, the randomness of the seed depends on the output -/// quality of the system's random number generator when the seed is created. -/// In particular, seeds generated when the system's entropy pool is abnormally -/// low such as during system boot may be of a lower quality. -/// -/// The default hashing algorithm is currently SipHash 1-3, though this is -/// subject to change at any point in the future. While its performance is very -/// competitive for medium sized keys, other hashing algorithms will outperform -/// it for small keys such as integers as well as large keys such as long -/// strings, though those algorithms will typically *not* protect against -/// attacks such as HashDoS. -/// -/// The hashing algorithm can be replaced on a per-`HashMap` basis using the -/// [`default`], [`with_hasher`], and [`with_capacity_and_hasher`] methods. Many -/// alternative algorithms are available on crates.io, such as the [`fnv`] crate. -/// -/// It is required that the keys implement the [`Eq`] and [`Hash`] traits, although -/// this can frequently be achieved by using `#[derive(PartialEq, Eq, Hash)]`. -/// If you implement these yourself, it is important that the following -/// property holds: -/// -/// ```text -/// k1 == k2 -> hash(k1) == hash(k2) -/// ``` -/// -/// In other words, if two keys are equal, their hashes must be equal. -/// -/// It is a logic error for a key to be modified in such a way that the key's -/// hash, as determined by the [`Hash`] trait, or its equality, as determined by -/// the [`Eq`] trait, changes while it is in the map. This is normally only -/// possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code. -/// -/// Relevant papers/articles: -/// -/// 1. Pedro Celis. ["Robin Hood Hashing"](https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf) -/// 2. Emmanuel Goossaert. ["Robin Hood -/// hashing"](http://codecapsule.com/2013/11/11/robin-hood-hashing/) -/// 3. Emmanuel Goossaert. ["Robin Hood hashing: backward shift -/// deletion"](http://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/) -/// -/// # Examples -/// -/// ``` -/// use std::collections::HashMap; -/// -/// // Type inference lets us omit an explicit type signature (which -/// // would be `HashMap<String, String>` in this example). -/// let mut book_reviews = HashMap::new(); -/// -/// // Review some books. -/// book_reviews.insert( -/// "Adventures of Huckleberry Finn".to_string(), -/// "My favorite book.".to_string(), -/// ); -/// book_reviews.insert( -/// "Grimms' Fairy Tales".to_string(), -/// "Masterpiece.".to_string(), -/// ); -/// book_reviews.insert( -/// "Pride and Prejudice".to_string(), -/// "Very enjoyable.".to_string(), -/// ); -/// book_reviews.insert( -/// "The Adventures of Sherlock Holmes".to_string(), -/// "Eye lyked it alot.".to_string(), -/// ); -/// -/// // Check for a specific one. -/// // When collections store owned values (String), they can still be -/// // queried using references (&str). -/// if !book_reviews.contains_key("Les Misérables") { -/// println!("We've got {} reviews, but Les Misérables ain't one.", -/// book_reviews.len()); -/// } -/// -/// // oops, this review has a lot of spelling mistakes, let's delete it. -/// book_reviews.remove("The Adventures of Sherlock Holmes"); -/// -/// // Look up the values associated with some keys. -/// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"]; -/// for &book in &to_find { -/// match book_reviews.get(book) { -/// Some(review) => println!("{}: {}", book, review), -/// None => println!("{} is unreviewed.", book) -/// } -/// } -/// -/// // Iterate over everything. -/// for (book, review) in &book_reviews { -/// println!("{}: \"{}\"", book, review); -/// } -/// ``` -/// -/// `HashMap` also implements an [`Entry API`](#method.entry), which allows -/// for more complex methods of getting, setting, updating and removing keys and -/// their values: -/// -/// ``` -/// use std::collections::HashMap; -/// -/// // type inference lets us omit an explicit type signature (which -/// // would be `HashMap<&str, u8>` in this example). -/// let mut player_stats = HashMap::new(); -/// -/// fn random_stat_buff() -> u8 { -/// // could actually return some random value here - let's just return -/// // some fixed value for now -/// 42 -/// } -/// -/// // insert a key only if it doesn't already exist -/// player_stats.entry("health").or_insert(100); -/// -/// // insert a key using a function that provides a new value only if it -/// // doesn't already exist -/// player_stats.entry("defence").or_insert_with(random_stat_buff); -/// -/// // update a key, guarding against the key possibly not being set -/// let stat = player_stats.entry("attack").or_insert(100); -/// *stat += random_stat_buff(); -/// ``` -/// -/// The easiest way to use `HashMap` with a custom type as key is to derive [`Eq`] and [`Hash`]. -/// We must also derive [`PartialEq`]. -/// -/// [`Eq`]: ../../std/cmp/trait.Eq.html -/// [`Hash`]: ../../std/hash/trait.Hash.html -/// [`PartialEq`]: ../../std/cmp/trait.PartialEq.html -/// [`RefCell`]: ../../std/cell/struct.RefCell.html -/// [`Cell`]: ../../std/cell/struct.Cell.html -/// [`default`]: #method.default -/// [`with_hasher`]: #method.with_hasher -/// [`with_capacity_and_hasher`]: #method.with_capacity_and_hasher -/// [`fnv`]: https://crates.io/crates/fnv -/// -/// ``` -/// use std::collections::HashMap; -/// -/// #[derive(Hash, Eq, PartialEq, Debug)] -/// struct Viking { -/// name: String, -/// country: String, -/// } -/// -/// impl Viking { -/// /// Create a new Viking. -/// fn new(name: &str, country: &str) -> Viking { -/// Viking { name: name.to_string(), country: country.to_string() } -/// } -/// } -/// -/// // Use a HashMap to store the vikings' health points. -/// let mut vikings = HashMap::new(); -/// -/// vikings.insert(Viking::new("Einar", "Norway"), 25); -/// vikings.insert(Viking::new("Olaf", "Denmark"), 24); -/// vikings.insert(Viking::new("Harald", "Iceland"), 12); -/// -/// // Use derived implementation to print the status of the vikings. -/// for (viking, health) in &vikings { -/// println!("{:?} has {} hp", viking, health); -/// } -/// ``` -/// -/// A `HashMap` with fixed list of elements can be initialized from an array: -/// -/// ``` -/// use std::collections::HashMap; -/// -/// fn main() { -/// let timber_resources: HashMap<&str, i32> = -/// [("Norway", 100), -/// ("Denmark", 50), -/// ("Iceland", 10)] -/// .iter().cloned().collect(); -/// // use the values stored in map -/// } -/// ``` - -#[derive(Clone)] -#[stable(feature = "rust1", since = "1.0.0")] -pub struct HashMap<K, V, S = RandomState> { - // All hashes are keyed on these values, to prevent hash collision attacks. - hash_builder: S, - - table: RawTable<K, V>, - - resize_policy: DefaultResizePolicy, -} - -/// Search for a pre-hashed key. -/// If you don't already know the hash, use search or search_mut instead -#[inline] -fn search_hashed<K, V, M, F>(table: M, hash: SafeHash, is_match: F) -> InternalEntry<K, V, M> - where M: Deref<Target = RawTable<K, V>>, - F: FnMut(&K) -> bool -{ - // This is the only function where capacity can be zero. To avoid - // undefined behavior when Bucket::new gets the raw bucket in this - // case, immediately return the appropriate search result. - if table.capacity() == 0 { - return InternalEntry::TableIsEmpty; - } - - search_hashed_nonempty(table, hash, is_match) -} - -/// Search for a pre-hashed key when the hash map is known to be non-empty. -#[inline] -fn search_hashed_nonempty<K, V, M, F>(table: M, hash: SafeHash, mut is_match: F) - -> InternalEntry<K, V, M> - where M: Deref<Target = RawTable<K, V>>, - F: FnMut(&K) -> bool -{ - // Do not check the capacity as an extra branch could slow the lookup. - - let size = table.size(); - let mut probe = Bucket::new(table, hash); - let mut displacement = 0; - - loop { - let full = match probe.peek() { - Empty(bucket) => { - // Found a hole! - return InternalEntry::Vacant { - hash, - elem: NoElem(bucket, displacement), - }; - } - Full(bucket) => bucket, - }; - - let probe_displacement = full.displacement(); - - if probe_displacement < displacement { - // Found a luckier bucket than me. - // We can finish the search early if we hit any bucket - // with a lower distance to initial bucket than we've probed. - return InternalEntry::Vacant { - hash, - elem: NeqElem(full, probe_displacement), - }; - } - - // If the hash doesn't match, it can't be this one.. - if hash == full.hash() { - // If the key doesn't match, it can't be this one.. - if is_match(full.read().0) { - return InternalEntry::Occupied { elem: full }; - } - } - displacement += 1; - probe = full.next(); - debug_assert!(displacement <= size); - } -} - -fn pop_internal<K, V>(starting_bucket: FullBucketMut<K, V>) - -> (K, V, &mut RawTable<K, V>) -{ - let (empty, retkey, retval) = starting_bucket.take(); - let mut gap = match empty.gap_peek() { - Ok(b) => b, - Err(b) => return (retkey, retval, b.into_table()), - }; - - while gap.full().displacement() != 0 { - gap = match gap.shift() { - Ok(b) => b, - Err(b) => { - return (retkey, retval, b.into_table()); - }, - }; - } - - // Now we've done all our shifting. Return the value we grabbed earlier. - (retkey, retval, gap.into_table()) -} - -/// Perform robin hood bucket stealing at the given `bucket`. You must -/// also pass that bucket's displacement so we don't have to recalculate it. -/// -/// `hash`, `key`, and `val` are the elements to "robin hood" into the hashtable. -fn robin_hood<'a, K: 'a, V: 'a>(bucket: FullBucketMut<'a, K, V>, - mut displacement: usize, - mut hash: SafeHash, - mut key: K, - mut val: V) - -> FullBucketMut<'a, K, V> { - let size = bucket.table().size(); - let raw_capacity = bucket.table().capacity(); - // There can be at most `size - dib` buckets to displace, because - // in the worst case, there are `size` elements and we already are - // `displacement` buckets away from the initial one. - let idx_end = (bucket.index() + size - bucket.displacement()) % raw_capacity; - // Save the *starting point*. - let mut bucket = bucket.stash(); - - loop { - let (old_hash, old_key, old_val) = bucket.replace(hash, key, val); - hash = old_hash; - key = old_key; - val = old_val; - - loop { - displacement += 1; - let probe = bucket.next(); - debug_assert!(probe.index() != idx_end); - - let full_bucket = match probe.peek() { - Empty(bucket) => { - // Found a hole! - let bucket = bucket.put(hash, key, val); - // Now that it's stolen, just read the value's pointer - // right out of the table! Go back to the *starting point*. - // - // This use of `into_table` is misleading. It turns the - // bucket, which is a FullBucket on top of a - // FullBucketMut, into just one FullBucketMut. The "table" - // refers to the inner FullBucketMut in this context. - return bucket.into_table(); - } - Full(bucket) => bucket, - }; - - let probe_displacement = full_bucket.displacement(); - - bucket = full_bucket; - - // Robin hood! Steal the spot. - if probe_displacement < displacement { - displacement = probe_displacement; - break; - } - } - } -} - -impl<K, V, S> HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher -{ - fn make_hash<X: ?Sized>(&self, x: &X) -> SafeHash - where X: Hash - { - table::make_hash(&self.hash_builder, x) - } - - /// Search for a key, yielding the index if it's found in the hashtable. - /// If you already have the hash for the key lying around, or if you need an - /// InternalEntry, use search_hashed or search_hashed_nonempty. - #[inline] - fn search<'a, Q: ?Sized>(&'a self, q: &Q) - -> Option<FullBucket<K, V, &'a RawTable<K, V>>> - where K: Borrow<Q>, - Q: Eq + Hash - { - if self.is_empty() { - return None; - } - - let hash = self.make_hash(q); - search_hashed_nonempty(&self.table, hash, |k| q.eq(k.borrow())) - .into_occupied_bucket() - } - - #[inline] - fn search_mut<'a, Q: ?Sized>(&'a mut self, q: &Q) - -> Option<FullBucket<K, V, &'a mut RawTable<K, V>>> - where K: Borrow<Q>, - Q: Eq + Hash - { - if self.is_empty() { - return None; - } - - let hash = self.make_hash(q); - search_hashed_nonempty(&mut self.table, hash, |k| q.eq(k.borrow())) - .into_occupied_bucket() - } - - // The caller should ensure that invariants by Robin Hood Hashing hold - // and that there's space in the underlying table. - fn insert_hashed_ordered(&mut self, hash: SafeHash, k: K, v: V) { - let mut buckets = Bucket::new(&mut self.table, hash); - let start_index = buckets.index(); - - loop { - // We don't need to compare hashes for value swap. - // Not even DIBs for Robin Hood. - buckets = match buckets.peek() { - Empty(empty) => { - empty.put(hash, k, v); - return; - } - Full(b) => b.into_bucket(), - }; - buckets.next(); - debug_assert!(buckets.index() != start_index); - } - } -} - -impl<K: Hash + Eq, V> HashMap<K, V, RandomState> { - /// Creates an empty `HashMap`. - /// - /// The hash map is initially created with a capacity of 0, so it will not allocate until it - /// is first inserted into. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map: HashMap<&str, i32> = HashMap::new(); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn new() -> HashMap<K, V, RandomState> { - Default::default() - } - - /// Creates an empty `HashMap` with the specified capacity. - /// - /// The hash map will be able to hold at least `capacity` elements without - /// reallocating. If `capacity` is 0, the hash map will not allocate. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map: HashMap<&str, i32> = HashMap::with_capacity(10); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn with_capacity(capacity: usize) -> HashMap<K, V, RandomState> { - HashMap::with_capacity_and_hasher(capacity, Default::default()) - } -} - -impl<K, V, S> HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher -{ - /// Creates an empty `HashMap` which will use the given hash builder to hash - /// keys. - /// - /// The created map has the default initial capacity. - /// - /// Warning: `hash_builder` is normally randomly generated, and - /// is designed to allow HashMaps to be resistant to attacks that - /// cause many collisions and very poor performance. Setting it - /// manually using this function can expose a DoS attack vector. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::RandomState; - /// - /// let s = RandomState::new(); - /// let mut map = HashMap::with_hasher(s); - /// map.insert(1, 2); - /// ``` - #[inline] - #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] - pub fn with_hasher(hash_builder: S) -> HashMap<K, V, S> { - HashMap { - hash_builder, - resize_policy: DefaultResizePolicy::new(), - table: RawTable::new(0), - } - } - - /// Creates an empty `HashMap` with the specified capacity, using `hash_builder` - /// to hash the keys. - /// - /// The hash map will be able to hold at least `capacity` elements without - /// reallocating. If `capacity` is 0, the hash map will not allocate. - /// - /// Warning: `hash_builder` is normally randomly generated, and - /// is designed to allow HashMaps to be resistant to attacks that - /// cause many collisions and very poor performance. Setting it - /// manually using this function can expose a DoS attack vector. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::RandomState; - /// - /// let s = RandomState::new(); - /// let mut map = HashMap::with_capacity_and_hasher(10, s); - /// map.insert(1, 2); - /// ``` - #[inline] - #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] - pub fn with_capacity_and_hasher(capacity: usize, hash_builder: S) -> HashMap<K, V, S> { - let resize_policy = DefaultResizePolicy::new(); - let raw_cap = resize_policy.raw_capacity(capacity); - HashMap { - hash_builder, - resize_policy, - table: RawTable::new(raw_cap), - } - } - - /// Returns a reference to the map's [`BuildHasher`]. - /// - /// [`BuildHasher`]: ../../std/hash/trait.BuildHasher.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::RandomState; - /// - /// let hasher = RandomState::new(); - /// let map: HashMap<i32, i32> = HashMap::with_hasher(hasher); - /// let hasher: &RandomState = map.hasher(); - /// ``` - #[stable(feature = "hashmap_public_hasher", since = "1.9.0")] - pub fn hasher(&self) -> &S { - &self.hash_builder - } - - /// Returns the number of elements the map can hold without reallocating. - /// - /// This number is a lower bound; the `HashMap<K, V>` might be able to hold - /// more, but is guaranteed to be able to hold at least this many. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// let map: HashMap<i32, i32> = HashMap::with_capacity(100); - /// assert!(map.capacity() >= 100); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn capacity(&self) -> usize { - self.resize_policy.capacity(self.raw_capacity()) - } - - /// Returns the hash map's raw capacity. - #[inline] - fn raw_capacity(&self) -> usize { - self.table.capacity() - } - - /// Reserves capacity for at least `additional` more elements to be inserted - /// in the `HashMap`. The collection may reserve more space to avoid - /// frequent reallocations. - /// - /// # Panics - /// - /// Panics if the new allocation size overflows [`usize`]. - /// - /// [`usize`]: ../../std/primitive.usize.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map: HashMap<&str, i32> = HashMap::new(); - /// map.reserve(10); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn reserve(&mut self, additional: usize) { - match self.reserve_internal(additional, Infallible) { - Err(CollectionAllocErr::CapacityOverflow) => panic!("capacity overflow"), - Err(CollectionAllocErr::AllocErr) => unreachable!(), - Ok(()) => { /* yay */ } - } - } - - /// Tries to reserve capacity for at least `additional` more elements to be inserted - /// in the given `HashMap<K,V>`. The collection may reserve more space to avoid - /// frequent reallocations. - /// - /// # Errors - /// - /// If the capacity overflows, or the allocator reports a failure, then an error - /// is returned. - /// - /// # Examples - /// - /// ``` - /// #![feature(try_reserve)] - /// use std::collections::HashMap; - /// let mut map: HashMap<&str, isize> = HashMap::new(); - /// map.try_reserve(10).expect("why is the test harness OOMing on 10 bytes?"); - /// ``` - #[unstable(feature = "try_reserve", reason = "new API", issue="48043")] - pub fn try_reserve(&mut self, additional: usize) -> Result<(), CollectionAllocErr> { - self.reserve_internal(additional, Fallible) - } - - fn reserve_internal(&mut self, additional: usize, fallibility: Fallibility) - -> Result<(), CollectionAllocErr> { - - let remaining = self.capacity() - self.len(); // this can't overflow - if remaining < additional { - let min_cap = self.len() - .checked_add(additional) - .ok_or(CollectionAllocErr::CapacityOverflow)?; - let raw_cap = self.resize_policy.try_raw_capacity(min_cap)?; - self.try_resize(raw_cap, fallibility)?; - } else if self.table.tag() && remaining <= self.len() { - // Probe sequence is too long and table is half full, - // resize early to reduce probing length. - let new_capacity = self.table.capacity() * 2; - self.try_resize(new_capacity, fallibility)?; - } - Ok(()) - } - - /// Resizes the internal vectors to a new capacity. It's your - /// responsibility to: - /// 1) Ensure `new_raw_cap` is enough for all the elements, accounting - /// for the load factor. - /// 2) Ensure `new_raw_cap` is a power of two or zero. - #[inline(never)] - #[cold] - fn try_resize( - &mut self, - new_raw_cap: usize, - fallibility: Fallibility, - ) -> Result<(), CollectionAllocErr> { - assert!(self.table.size() <= new_raw_cap); - assert!(new_raw_cap.is_power_of_two() || new_raw_cap == 0); - - let mut old_table = replace( - &mut self.table, - match fallibility { - Infallible => RawTable::new(new_raw_cap), - Fallible => RawTable::try_new(new_raw_cap)?, - } - ); - let old_size = old_table.size(); - - if old_table.size() == 0 { - return Ok(()); - } - - let mut bucket = Bucket::head_bucket(&mut old_table); - - // This is how the buckets might be laid out in memory: - // ($ marks an initialized bucket) - // ________________ - // |$$$_$$$$$$_$$$$$| - // - // But we've skipped the entire initial cluster of buckets - // and will continue iteration in this order: - // ________________ - // |$$$$$$_$$$$$ - // ^ wrap around once end is reached - // ________________ - // $$$_____________| - // ^ exit once table.size == 0 - loop { - bucket = match bucket.peek() { - Full(bucket) => { - let h = bucket.hash(); - let (b, k, v) = bucket.take(); - self.insert_hashed_ordered(h, k, v); - if b.table().size() == 0 { - break; - } - b.into_bucket() - } - Empty(b) => b.into_bucket(), - }; - bucket.next(); - } - - assert_eq!(self.table.size(), old_size); - Ok(()) - } - - /// Shrinks the capacity of the map as much as possible. It will drop - /// down as much as possible while maintaining the internal rules - /// and possibly leaving some space in accordance with the resize policy. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<i32, i32> = HashMap::with_capacity(100); - /// map.insert(1, 2); - /// map.insert(3, 4); - /// assert!(map.capacity() >= 100); - /// map.shrink_to_fit(); - /// assert!(map.capacity() >= 2); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn shrink_to_fit(&mut self) { - let new_raw_cap = self.resize_policy.raw_capacity(self.len()); - if self.raw_capacity() != new_raw_cap { - let old_table = replace(&mut self.table, RawTable::new(new_raw_cap)); - let old_size = old_table.size(); - - // Shrink the table. Naive algorithm for resizing: - for (h, k, v) in old_table.into_iter() { - self.insert_hashed_nocheck(h, k, v); - } - - debug_assert_eq!(self.table.size(), old_size); - } - } - - /// Shrinks the capacity of the map with a lower limit. It will drop - /// down no lower than the supplied limit while maintaining the internal rules - /// and possibly leaving some space in accordance with the resize policy. - /// - /// Panics if the current capacity is smaller than the supplied - /// minimum capacity. - /// - /// # Examples - /// - /// ``` - /// #![feature(shrink_to)] - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<i32, i32> = HashMap::with_capacity(100); - /// map.insert(1, 2); - /// map.insert(3, 4); - /// assert!(map.capacity() >= 100); - /// map.shrink_to(10); - /// assert!(map.capacity() >= 10); - /// map.shrink_to(0); - /// assert!(map.capacity() >= 2); - /// ``` - #[unstable(feature = "shrink_to", reason = "new API", issue="0")] - pub fn shrink_to(&mut self, min_capacity: usize) { - assert!(self.capacity() >= min_capacity, "Tried to shrink to a larger capacity"); - - let new_raw_cap = self.resize_policy.raw_capacity(max(self.len(), min_capacity)); - if self.raw_capacity() != new_raw_cap { - let old_table = replace(&mut self.table, RawTable::new(new_raw_cap)); - let old_size = old_table.size(); - - // Shrink the table. Naive algorithm for resizing: - for (h, k, v) in old_table.into_iter() { - self.insert_hashed_nocheck(h, k, v); - } - - debug_assert_eq!(self.table.size(), old_size); - } - } - - /// Insert a pre-hashed key-value pair, without first checking - /// that there's enough room in the buckets. Returns a reference to the - /// newly insert value. - /// - /// If the key already exists, the hashtable will be returned untouched - /// and a reference to the existing element will be returned. - fn insert_hashed_nocheck(&mut self, hash: SafeHash, k: K, v: V) -> Option<V> { - let entry = search_hashed(&mut self.table, hash, |key| *key == k).into_entry(k); - match entry { - Some(Occupied(mut elem)) => Some(elem.insert(v)), - Some(Vacant(elem)) => { - elem.insert(v); - None - } - None => unreachable!(), - } - } - - /// An iterator visiting all keys in arbitrary order. - /// The iterator element type is `&'a K`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// for key in map.keys() { - /// println!("{}", key); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn keys(&self) -> Keys<K, V> { - Keys { inner: self.iter() } - } - - /// An iterator visiting all values in arbitrary order. - /// The iterator element type is `&'a V`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// for val in map.values() { - /// println!("{}", val); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn values(&self) -> Values<K, V> { - Values { inner: self.iter() } - } - - /// An iterator visiting all values mutably in arbitrary order. - /// The iterator element type is `&'a mut V`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// - /// map.insert("a", 1); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// for val in map.values_mut() { - /// *val = *val + 10; - /// } - /// - /// for val in map.values() { - /// println!("{}", val); - /// } - /// ``` - #[stable(feature = "map_values_mut", since = "1.10.0")] - pub fn values_mut(&mut self) -> ValuesMut<K, V> { - ValuesMut { inner: self.iter_mut() } - } - - /// An iterator visiting all key-value pairs in arbitrary order. - /// The iterator element type is `(&'a K, &'a V)`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// for (key, val) in map.iter() { - /// println!("key: {} val: {}", key, val); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn iter(&self) -> Iter<K, V> { - Iter { inner: self.table.iter() } - } - - /// An iterator visiting all key-value pairs in arbitrary order, - /// with mutable references to the values. - /// The iterator element type is `(&'a K, &'a mut V)`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// // Update all values - /// for (_, val) in map.iter_mut() { - /// *val *= 2; - /// } - /// - /// for (key, val) in &map { - /// println!("key: {} val: {}", key, val); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn iter_mut(&mut self) -> IterMut<K, V> { - IterMut { inner: self.table.iter_mut() } - } - - /// Gets the given key's corresponding entry in the map for in-place manipulation. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut letters = HashMap::new(); - /// - /// for ch in "a short treatise on fungi".chars() { - /// let counter = letters.entry(ch).or_insert(0); - /// *counter += 1; - /// } - /// - /// assert_eq!(letters[&'s'], 2); - /// assert_eq!(letters[&'t'], 3); - /// assert_eq!(letters[&'u'], 1); - /// assert_eq!(letters.get(&'y'), None); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn entry(&mut self, key: K) -> Entry<K, V> { - // Gotta resize now. - self.reserve(1); - let hash = self.make_hash(&key); - search_hashed(&mut self.table, hash, |q| q.eq(&key)) - .into_entry(key).expect("unreachable") - } - - /// Returns the number of elements in the map. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut a = HashMap::new(); - /// assert_eq!(a.len(), 0); - /// a.insert(1, "a"); - /// assert_eq!(a.len(), 1); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn len(&self) -> usize { - self.table.size() - } - - /// Returns true if the map contains no elements. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut a = HashMap::new(); - /// assert!(a.is_empty()); - /// a.insert(1, "a"); - /// assert!(!a.is_empty()); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_empty(&self) -> bool { - self.len() == 0 - } - - /// Clears the map, returning all key-value pairs as an iterator. Keeps the - /// allocated memory for reuse. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut a = HashMap::new(); - /// a.insert(1, "a"); - /// a.insert(2, "b"); - /// - /// for (k, v) in a.drain().take(1) { - /// assert!(k == 1 || k == 2); - /// assert!(v == "a" || v == "b"); - /// } - /// - /// assert!(a.is_empty()); - /// ``` - #[inline] - #[stable(feature = "drain", since = "1.6.0")] - pub fn drain(&mut self) -> Drain<K, V> { - Drain { inner: self.table.drain() } - } - - /// Clears the map, removing all key-value pairs. Keeps the allocated memory - /// for reuse. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut a = HashMap::new(); - /// a.insert(1, "a"); - /// a.clear(); - /// assert!(a.is_empty()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub fn clear(&mut self) { - self.drain(); - } - - /// Returns a reference to the value corresponding to the key. - /// - /// The key may be any borrowed form of the map's key type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the key type. - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.get(&1), Some(&"a")); - /// assert_eq!(map.get(&2), None); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - #[inline] - pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V> - where K: Borrow<Q>, - Q: Hash + Eq - { - self.search(k).map(|bucket| bucket.into_refs().1) - } - - /// Returns the key-value pair corresponding to the supplied key. - /// - /// The supplied key may be any borrowed form of the map's key type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the key type. - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - /// - /// # Examples - /// - /// ``` - /// #![feature(map_get_key_value)] - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.get_key_value(&1), Some((&1, &"a"))); - /// assert_eq!(map.get_key_value(&2), None); - /// ``` - #[unstable(feature = "map_get_key_value", issue = "49347")] - pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)> - where K: Borrow<Q>, - Q: Hash + Eq - { - self.search(k).map(|bucket| bucket.into_refs()) - } - - /// Returns true if the map contains a value for the specified key. - /// - /// The key may be any borrowed form of the map's key type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the key type. - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.contains_key(&1), true); - /// assert_eq!(map.contains_key(&2), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool - where K: Borrow<Q>, - Q: Hash + Eq - { - self.search(k).is_some() - } - - /// Returns a mutable reference to the value corresponding to the key. - /// - /// The key may be any borrowed form of the map's key type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the key type. - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert(1, "a"); - /// if let Some(x) = map.get_mut(&1) { - /// *x = "b"; - /// } - /// assert_eq!(map[&1], "b"); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V> - where K: Borrow<Q>, - Q: Hash + Eq - { - self.search_mut(k).map(|bucket| bucket.into_mut_refs().1) - } - - /// Inserts a key-value pair into the map. - /// - /// If the map did not have this key present, [`None`] is returned. - /// - /// If the map did have this key present, the value is updated, and the old - /// value is returned. The key is not updated, though; this matters for - /// types that can be `==` without being identical. See the [module-level - /// documentation] for more. - /// - /// [`None`]: ../../std/option/enum.Option.html#variant.None - /// [module-level documentation]: index.html#insert-and-complex-keys - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// assert_eq!(map.insert(37, "a"), None); - /// assert_eq!(map.is_empty(), false); - /// - /// map.insert(37, "b"); - /// assert_eq!(map.insert(37, "c"), Some("b")); - /// assert_eq!(map[&37], "c"); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn insert(&mut self, k: K, v: V) -> Option<V> { - let hash = self.make_hash(&k); - self.reserve(1); - self.insert_hashed_nocheck(hash, k, v) - } - - /// Removes a key from the map, returning the value at the key if the key - /// was previously in the map. - /// - /// The key may be any borrowed form of the map's key type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the key type. - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.remove(&1), Some("a")); - /// assert_eq!(map.remove(&1), None); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V> - where K: Borrow<Q>, - Q: Hash + Eq - { - self.search_mut(k).map(|bucket| pop_internal(bucket).1) - } - - /// Removes a key from the map, returning the stored key and value if the - /// key was previously in the map. - /// - /// The key may be any borrowed form of the map's key type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the key type. - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// # fn main() { - /// let mut map = HashMap::new(); - /// map.insert(1, "a"); - /// assert_eq!(map.remove_entry(&1), Some((1, "a"))); - /// assert_eq!(map.remove(&1), None); - /// # } - /// ``` - #[stable(feature = "hash_map_remove_entry", since = "1.27.0")] - pub fn remove_entry<Q: ?Sized>(&mut self, k: &Q) -> Option<(K, V)> - where K: Borrow<Q>, - Q: Hash + Eq - { - self.search_mut(k) - .map(|bucket| { - let (k, v, _) = pop_internal(bucket); - (k, v) - }) - } - - /// Retains only the elements specified by the predicate. - /// - /// In other words, remove all pairs `(k, v)` such that `f(&k,&mut v)` returns `false`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<i32, i32> = (0..8).map(|x|(x, x*10)).collect(); - /// map.retain(|&k, _| k % 2 == 0); - /// assert_eq!(map.len(), 4); - /// ``` - #[stable(feature = "retain_hash_collection", since = "1.18.0")] - pub fn retain<F>(&mut self, mut f: F) - where F: FnMut(&K, &mut V) -> bool - { - if self.table.size() == 0 { - return; - } - let mut elems_left = self.table.size(); - let mut bucket = Bucket::head_bucket(&mut self.table); - bucket.prev(); - let start_index = bucket.index(); - while elems_left != 0 { - bucket = match bucket.peek() { - Full(mut full) => { - elems_left -= 1; - let should_remove = { - let (k, v) = full.read_mut(); - !f(k, v) - }; - if should_remove { - let prev_raw = full.raw(); - let (_, _, t) = pop_internal(full); - Bucket::new_from(prev_raw, t) - } else { - full.into_bucket() - } - }, - Empty(b) => { - b.into_bucket() - } - }; - bucket.prev(); // reverse iteration - debug_assert!(elems_left == 0 || bucket.index() != start_index); - } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V, S> PartialEq for HashMap<K, V, S> - where K: Eq + Hash, - V: PartialEq, - S: BuildHasher -{ - fn eq(&self, other: &HashMap<K, V, S>) -> bool { - if self.len() != other.len() { - return false; - } - - self.iter().all(|(key, value)| other.get(key).map_or(false, |v| *value == *v)) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V, S> Eq for HashMap<K, V, S> - where K: Eq + Hash, - V: Eq, - S: BuildHasher -{ -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V, S> Debug for HashMap<K, V, S> - where K: Eq + Hash + Debug, - V: Debug, - S: BuildHasher -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_map().entries(self.iter()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V, S> Default for HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher + Default -{ - /// Creates an empty `HashMap<K, V, S>`, with the `Default` value for the hasher. - fn default() -> HashMap<K, V, S> { - HashMap::with_hasher(Default::default()) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, Q: ?Sized, V, S> Index<&'a Q> for HashMap<K, V, S> - where K: Eq + Hash + Borrow<Q>, - Q: Eq + Hash, - S: BuildHasher -{ - type Output = V; - - /// Returns a reference to the value corresponding to the supplied key. - /// - /// # Panics - /// - /// Panics if the key is not present in the `HashMap`. - #[inline] - fn index(&self, key: &Q) -> &V { - self.get(key).expect("no entry found for key") - } -} - -/// An iterator over the entries of a `HashMap`. -/// -/// This `struct` is created by the [`iter`] method on [`HashMap`]. See its -/// documentation for more. -/// -/// [`iter`]: struct.HashMap.html#method.iter -/// [`HashMap`]: struct.HashMap.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Iter<'a, K: 'a, V: 'a> { - inner: table::Iter<'a, K, V>, -} - -// FIXME(#26925) Remove in favor of `#[derive(Clone)]` -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Clone for Iter<'a, K, V> { - fn clone(&self) -> Iter<'a, K, V> { - Iter { inner: self.inner.clone() } - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K: Debug, V: Debug> fmt::Debug for Iter<'a, K, V> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list() - .entries(self.clone()) - .finish() - } -} - -/// A mutable iterator over the entries of a `HashMap`. -/// -/// This `struct` is created by the [`iter_mut`] method on [`HashMap`]. See its -/// documentation for more. -/// -/// [`iter_mut`]: struct.HashMap.html#method.iter_mut -/// [`HashMap`]: struct.HashMap.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct IterMut<'a, K: 'a, V: 'a> { - inner: table::IterMut<'a, K, V>, -} - -/// An owning iterator over the entries of a `HashMap`. -/// -/// This `struct` is created by the [`into_iter`] method on [`HashMap`][`HashMap`] -/// (provided by the `IntoIterator` trait). See its documentation for more. -/// -/// [`into_iter`]: struct.HashMap.html#method.into_iter -/// [`HashMap`]: struct.HashMap.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct IntoIter<K, V> { - pub(super) inner: table::IntoIter<K, V>, -} - -/// An iterator over the keys of a `HashMap`. -/// -/// This `struct` is created by the [`keys`] method on [`HashMap`]. See its -/// documentation for more. -/// -/// [`keys`]: struct.HashMap.html#method.keys -/// [`HashMap`]: struct.HashMap.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Keys<'a, K: 'a, V: 'a> { - inner: Iter<'a, K, V>, -} - -// FIXME(#26925) Remove in favor of `#[derive(Clone)]` -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Clone for Keys<'a, K, V> { - fn clone(&self) -> Keys<'a, K, V> { - Keys { inner: self.inner.clone() } - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K: Debug, V> fmt::Debug for Keys<'a, K, V> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list() - .entries(self.clone()) - .finish() - } -} - -/// An iterator over the values of a `HashMap`. -/// -/// This `struct` is created by the [`values`] method on [`HashMap`]. See its -/// documentation for more. -/// -/// [`values`]: struct.HashMap.html#method.values -/// [`HashMap`]: struct.HashMap.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Values<'a, K: 'a, V: 'a> { - inner: Iter<'a, K, V>, -} - -// FIXME(#26925) Remove in favor of `#[derive(Clone)]` -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Clone for Values<'a, K, V> { - fn clone(&self) -> Values<'a, K, V> { - Values { inner: self.inner.clone() } - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K, V: Debug> fmt::Debug for Values<'a, K, V> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list() - .entries(self.clone()) - .finish() - } -} - -/// A draining iterator over the entries of a `HashMap`. -/// -/// This `struct` is created by the [`drain`] method on [`HashMap`]. See its -/// documentation for more. -/// -/// [`drain`]: struct.HashMap.html#method.drain -/// [`HashMap`]: struct.HashMap.html -#[stable(feature = "drain", since = "1.6.0")] -pub struct Drain<'a, K: 'a, V: 'a> { - pub(super) inner: table::Drain<'a, K, V>, -} - -/// A mutable iterator over the values of a `HashMap`. -/// -/// This `struct` is created by the [`values_mut`] method on [`HashMap`]. See its -/// documentation for more. -/// -/// [`values_mut`]: struct.HashMap.html#method.values_mut -/// [`HashMap`]: struct.HashMap.html -#[stable(feature = "map_values_mut", since = "1.10.0")] -pub struct ValuesMut<'a, K: 'a, V: 'a> { - inner: IterMut<'a, K, V>, -} - -enum InternalEntry<K, V, M> { - Occupied { elem: FullBucket<K, V, M> }, - Vacant { - hash: SafeHash, - elem: VacantEntryState<K, V, M>, - }, - TableIsEmpty, -} - -impl<K, V, M> InternalEntry<K, V, M> { - #[inline] - fn into_occupied_bucket(self) -> Option<FullBucket<K, V, M>> { - match self { - InternalEntry::Occupied { elem } => Some(elem), - _ => None, - } - } -} - -impl<'a, K, V> InternalEntry<K, V, &'a mut RawTable<K, V>> { - #[inline] - fn into_entry(self, key: K) -> Option<Entry<'a, K, V>> { - match self { - InternalEntry::Occupied { elem } => { - Some(Occupied(OccupiedEntry { - key: Some(key), - elem, - })) - } - InternalEntry::Vacant { hash, elem } => { - Some(Vacant(VacantEntry { - hash, - key, - elem, - })) - } - InternalEntry::TableIsEmpty => None, - } - } -} - -/// A view into a single entry in a map, which may either be vacant or occupied. -/// -/// This `enum` is constructed from the [`entry`] method on [`HashMap`]. -/// -/// [`HashMap`]: struct.HashMap.html -/// [`entry`]: struct.HashMap.html#method.entry -#[stable(feature = "rust1", since = "1.0.0")] -pub enum Entry<'a, K: 'a, V: 'a> { - /// An occupied entry. - #[stable(feature = "rust1", since = "1.0.0")] - Occupied(#[stable(feature = "rust1", since = "1.0.0")] - OccupiedEntry<'a, K, V>), - - /// A vacant entry. - #[stable(feature = "rust1", since = "1.0.0")] - Vacant(#[stable(feature = "rust1", since = "1.0.0")] - VacantEntry<'a, K, V>), -} - -#[stable(feature= "debug_hash_map", since = "1.12.0")] -impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for Entry<'a, K, V> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - match *self { - Vacant(ref v) => { - f.debug_tuple("Entry") - .field(v) - .finish() - } - Occupied(ref o) => { - f.debug_tuple("Entry") - .field(o) - .finish() - } - } - } -} - -/// A view into an occupied entry in a `HashMap`. -/// It is part of the [`Entry`] enum. -/// -/// [`Entry`]: enum.Entry.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct OccupiedEntry<'a, K: 'a, V: 'a> { - key: Option<K>, - elem: FullBucket<K, V, &'a mut RawTable<K, V>>, -} - -#[stable(feature= "debug_hash_map", since = "1.12.0")] -impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for OccupiedEntry<'a, K, V> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_struct("OccupiedEntry") - .field("key", self.key()) - .field("value", self.get()) - .finish() - } -} - -/// A view into a vacant entry in a `HashMap`. -/// It is part of the [`Entry`] enum. -/// -/// [`Entry`]: enum.Entry.html -#[stable(feature = "rust1", since = "1.0.0")] -pub struct VacantEntry<'a, K: 'a, V: 'a> { - hash: SafeHash, - key: K, - elem: VacantEntryState<K, V, &'a mut RawTable<K, V>>, -} - -#[stable(feature= "debug_hash_map", since = "1.12.0")] -impl<'a, K: 'a + Debug, V: 'a> Debug for VacantEntry<'a, K, V> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_tuple("VacantEntry") - .field(self.key()) - .finish() - } -} - -/// Possible states of a VacantEntry. -enum VacantEntryState<K, V, M> { - /// The index is occupied, but the key to insert has precedence, - /// and will kick the current one out on insertion. - NeqElem(FullBucket<K, V, M>, usize), - /// The index is genuinely vacant. - NoElem(EmptyBucket<K, V, M>, usize), -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher -{ - type Item = (&'a K, &'a V); - type IntoIter = Iter<'a, K, V>; - - fn into_iter(self) -> Iter<'a, K, V> { - self.iter() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher -{ - type Item = (&'a K, &'a mut V); - type IntoIter = IterMut<'a, K, V>; - - fn into_iter(self) -> IterMut<'a, K, V> { - self.iter_mut() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V, S> IntoIterator for HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher -{ - type Item = (K, V); - type IntoIter = IntoIter<K, V>; - - /// Creates a consuming iterator, that is, one that moves each key-value - /// pair out of the map in arbitrary order. The map cannot be used after - /// calling this. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// // Not possible with .iter() - /// let vec: Vec<(&str, i32)> = map.into_iter().collect(); - /// ``` - fn into_iter(self) -> IntoIter<K, V> { - IntoIter { inner: self.table.into_iter() } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Iterator for Iter<'a, K, V> { - type Item = (&'a K, &'a V); - - #[inline] - fn next(&mut self) -> Option<(&'a K, &'a V)> { - self.inner.next() - } - #[inline] - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> { - #[inline] - fn len(&self) -> usize { - self.inner.len() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K, V> FusedIterator for Iter<'a, K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Iterator for IterMut<'a, K, V> { - type Item = (&'a K, &'a mut V); - - #[inline] - fn next(&mut self) -> Option<(&'a K, &'a mut V)> { - self.inner.next() - } - #[inline] - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> { - #[inline] - fn len(&self) -> usize { - self.inner.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K, V> FusedIterator for IterMut<'a, K, V> {} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K, V> fmt::Debug for IterMut<'a, K, V> - where K: fmt::Debug, - V: fmt::Debug, -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list() - .entries(self.inner.iter()) - .finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> Iterator for IntoIter<K, V> { - type Item = (K, V); - - #[inline] - fn next(&mut self) -> Option<(K, V)> { - self.inner.next().map(|(_, k, v)| (k, v)) - } - #[inline] - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V> ExactSizeIterator for IntoIter<K, V> { - #[inline] - fn len(&self) -> usize { - self.inner.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<K, V> FusedIterator for IntoIter<K, V> {} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<K: Debug, V: Debug> fmt::Debug for IntoIter<K, V> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list() - .entries(self.inner.iter()) - .finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Iterator for Keys<'a, K, V> { - type Item = &'a K; - - #[inline] - fn next(&mut self) -> Option<(&'a K)> { - self.inner.next().map(|(k, _)| k) - } - #[inline] - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> { - #[inline] - fn len(&self) -> usize { - self.inner.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K, V> FusedIterator for Keys<'a, K, V> {} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> Iterator for Values<'a, K, V> { - type Item = &'a V; - - #[inline] - fn next(&mut self) -> Option<(&'a V)> { - self.inner.next().map(|(_, v)| v) - } - #[inline] - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> { - #[inline] - fn len(&self) -> usize { - self.inner.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K, V> FusedIterator for Values<'a, K, V> {} - -#[stable(feature = "map_values_mut", since = "1.10.0")] -impl<'a, K, V> Iterator for ValuesMut<'a, K, V> { - type Item = &'a mut V; - - #[inline] - fn next(&mut self) -> Option<(&'a mut V)> { - self.inner.next().map(|(_, v)| v) - } - #[inline] - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} -#[stable(feature = "map_values_mut", since = "1.10.0")] -impl<'a, K, V> ExactSizeIterator for ValuesMut<'a, K, V> { - #[inline] - fn len(&self) -> usize { - self.inner.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K, V> FusedIterator for ValuesMut<'a, K, V> {} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K, V> fmt::Debug for ValuesMut<'a, K, V> - where K: fmt::Debug, - V: fmt::Debug, -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list() - .entries(self.inner.inner.iter()) - .finish() - } -} - -#[stable(feature = "drain", since = "1.6.0")] -impl<'a, K, V> Iterator for Drain<'a, K, V> { - type Item = (K, V); - - #[inline] - fn next(&mut self) -> Option<(K, V)> { - self.inner.next().map(|(_, k, v)| (k, v)) - } - #[inline] - fn size_hint(&self) -> (usize, Option<usize>) { - self.inner.size_hint() - } -} -#[stable(feature = "drain", since = "1.6.0")] -impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> { - #[inline] - fn len(&self) -> usize { - self.inner.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K, V> FusedIterator for Drain<'a, K, V> {} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K, V> fmt::Debug for Drain<'a, K, V> - where K: fmt::Debug, - V: fmt::Debug, -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list() - .entries(self.inner.iter()) - .finish() - } -} - -impl<'a, K, V> Entry<'a, K, V> { - #[stable(feature = "rust1", since = "1.0.0")] - /// Ensures a value is in the entry by inserting the default if empty, and returns - /// a mutable reference to the value in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// assert_eq!(map["poneyland"], 12); - /// - /// *map.entry("poneyland").or_insert(12) += 10; - /// assert_eq!(map["poneyland"], 22); - /// ``` - pub fn or_insert(self, default: V) -> &'a mut V { - match self { - Occupied(entry) => entry.into_mut(), - Vacant(entry) => entry.insert(default), - } - } - - #[stable(feature = "rust1", since = "1.0.0")] - /// Ensures a value is in the entry by inserting the result of the default function if empty, - /// and returns a mutable reference to the value in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<&str, String> = HashMap::new(); - /// let s = "hoho".to_string(); - /// - /// map.entry("poneyland").or_insert_with(|| s); - /// - /// assert_eq!(map["poneyland"], "hoho".to_string()); - /// ``` - pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V { - match self { - Occupied(entry) => entry.into_mut(), - Vacant(entry) => entry.insert(default()), - } - } - - /// Returns a reference to this entry's key. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); - /// ``` - #[stable(feature = "map_entry_keys", since = "1.10.0")] - pub fn key(&self) -> &K { - match *self { - Occupied(ref entry) => entry.key(), - Vacant(ref entry) => entry.key(), - } - } - - /// Provides in-place mutable access to an occupied entry before any - /// potential inserts into the map. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// - /// map.entry("poneyland") - /// .and_modify(|e| { *e += 1 }) - /// .or_insert(42); - /// assert_eq!(map["poneyland"], 42); - /// - /// map.entry("poneyland") - /// .and_modify(|e| { *e += 1 }) - /// .or_insert(42); - /// assert_eq!(map["poneyland"], 43); - /// ``` - #[stable(feature = "entry_and_modify", since = "1.26.0")] - pub fn and_modify<F>(self, f: F) -> Self - where F: FnOnce(&mut V) - { - match self { - Occupied(mut entry) => { - f(entry.get_mut()); - Occupied(entry) - }, - Vacant(entry) => Vacant(entry), - } - } - -} - -impl<'a, K, V: Default> Entry<'a, K, V> { - #[stable(feature = "entry_or_default", since = "1.28.0")] - /// Ensures a value is in the entry by inserting the default value if empty, - /// and returns a mutable reference to the value in the entry. - /// - /// # Examples - /// - /// ``` - /// # fn main() { - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<&str, Option<u32>> = HashMap::new(); - /// map.entry("poneyland").or_default(); - /// - /// assert_eq!(map["poneyland"], None); - /// # } - /// ``` - pub fn or_default(self) -> &'a mut V { - match self { - Occupied(entry) => entry.into_mut(), - Vacant(entry) => entry.insert(Default::default()), - } - } -} - -impl<'a, K, V> OccupiedEntry<'a, K, V> { - /// Gets a reference to the key in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); - /// ``` - #[stable(feature = "map_entry_keys", since = "1.10.0")] - pub fn key(&self) -> &K { - self.elem.read().0 - } - - /// Take the ownership of the key and value from the map. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// // We delete the entry from the map. - /// o.remove_entry(); - /// } - /// - /// assert_eq!(map.contains_key("poneyland"), false); - /// ``` - #[stable(feature = "map_entry_recover_keys2", since = "1.12.0")] - pub fn remove_entry(self) -> (K, V) { - let (k, v, _) = pop_internal(self.elem); - (k, v) - } - - /// Gets a reference to the value in the entry. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// assert_eq!(o.get(), &12); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn get(&self) -> &V { - self.elem.read().1 - } - - /// Gets a mutable reference to the value in the entry. - /// - /// If you need a reference to the `OccupiedEntry` which may outlive the - /// destruction of the `Entry` value, see [`into_mut`]. - /// - /// [`into_mut`]: #method.into_mut - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// assert_eq!(map["poneyland"], 12); - /// if let Entry::Occupied(mut o) = map.entry("poneyland") { - /// *o.get_mut() += 10; - /// assert_eq!(*o.get(), 22); - /// - /// // We can use the same Entry multiple times. - /// *o.get_mut() += 2; - /// } - /// - /// assert_eq!(map["poneyland"], 24); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn get_mut(&mut self) -> &mut V { - self.elem.read_mut().1 - } - - /// Converts the OccupiedEntry into a mutable reference to the value in the entry - /// with a lifetime bound to the map itself. - /// - /// If you need multiple references to the `OccupiedEntry`, see [`get_mut`]. - /// - /// [`get_mut`]: #method.get_mut - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// assert_eq!(map["poneyland"], 12); - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// *o.into_mut() += 10; - /// } - /// - /// assert_eq!(map["poneyland"], 22); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn into_mut(self) -> &'a mut V { - self.elem.into_mut_refs().1 - } - - /// Sets the value of the entry, and returns the entry's old value. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(mut o) = map.entry("poneyland") { - /// assert_eq!(o.insert(15), 12); - /// } - /// - /// assert_eq!(map["poneyland"], 15); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn insert(&mut self, mut value: V) -> V { - let old_value = self.get_mut(); - mem::swap(&mut value, old_value); - value - } - - /// Takes the value out of the entry, and returns it. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// map.entry("poneyland").or_insert(12); - /// - /// if let Entry::Occupied(o) = map.entry("poneyland") { - /// assert_eq!(o.remove(), 12); - /// } - /// - /// assert_eq!(map.contains_key("poneyland"), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn remove(self) -> V { - pop_internal(self.elem).1 - } - - /// Returns a key that was used for search. - /// - /// The key was retained for further use. - fn take_key(&mut self) -> Option<K> { - self.key.take() - } - - /// Replaces the entry, returning the old key and value. The new key in the hash map will be - /// the key used to create this entry. - /// - /// # Examples - /// - /// ``` - /// #![feature(map_entry_replace)] - /// use std::collections::hash_map::{Entry, HashMap}; - /// use std::rc::Rc; - /// - /// let mut map: HashMap<Rc<String>, u32> = HashMap::new(); - /// map.insert(Rc::new("Stringthing".to_string()), 15); - /// - /// let my_key = Rc::new("Stringthing".to_string()); - /// - /// if let Entry::Occupied(entry) = map.entry(my_key) { - /// // Also replace the key with a handle to our other key. - /// let (old_key, old_value): (Rc<String>, u32) = entry.replace_entry(16); - /// } - /// - /// ``` - #[unstable(feature = "map_entry_replace", issue = "44286")] - pub fn replace_entry(mut self, value: V) -> (K, V) { - let (old_key, old_value) = self.elem.read_mut(); - - let old_key = mem::replace(old_key, self.key.unwrap()); - let old_value = mem::replace(old_value, value); - - (old_key, old_value) - } - - /// Replaces the key in the hash map with the key used to create this entry. - /// - /// # Examples - /// - /// ``` - /// #![feature(map_entry_replace)] - /// use std::collections::hash_map::{Entry, HashMap}; - /// use std::rc::Rc; - /// - /// let mut map: HashMap<Rc<String>, u32> = HashMap::new(); - /// let mut known_strings: Vec<Rc<String>> = Vec::new(); - /// - /// // Initialise known strings, run program, etc. - /// - /// reclaim_memory(&mut map, &known_strings); - /// - /// fn reclaim_memory(map: &mut HashMap<Rc<String>, u32>, known_strings: &[Rc<String>] ) { - /// for s in known_strings { - /// if let Entry::Occupied(entry) = map.entry(s.clone()) { - /// // Replaces the entry's key with our version of it in `known_strings`. - /// entry.replace_key(); - /// } - /// } - /// } - /// ``` - #[unstable(feature = "map_entry_replace", issue = "44286")] - pub fn replace_key(mut self) -> K { - let (old_key, _) = self.elem.read_mut(); - mem::replace(old_key, self.key.unwrap()) - } -} - -impl<'a, K: 'a, V: 'a> VacantEntry<'a, K, V> { - /// Gets a reference to the key that would be used when inserting a value - /// through the `VacantEntry`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// assert_eq!(map.entry("poneyland").key(), &"poneyland"); - /// ``` - #[stable(feature = "map_entry_keys", since = "1.10.0")] - pub fn key(&self) -> &K { - &self.key - } - - /// Take ownership of the key. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// - /// if let Entry::Vacant(v) = map.entry("poneyland") { - /// v.into_key(); - /// } - /// ``` - #[stable(feature = "map_entry_recover_keys2", since = "1.12.0")] - pub fn into_key(self) -> K { - self.key - } - - /// Sets the value of the entry with the VacantEntry's key, - /// and returns a mutable reference to it. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashMap; - /// use std::collections::hash_map::Entry; - /// - /// let mut map: HashMap<&str, u32> = HashMap::new(); - /// - /// if let Entry::Vacant(o) = map.entry("poneyland") { - /// o.insert(37); - /// } - /// assert_eq!(map["poneyland"], 37); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn insert(self, value: V) -> &'a mut V { - let b = match self.elem { - NeqElem(mut bucket, disp) => { - if disp >= DISPLACEMENT_THRESHOLD { - bucket.table_mut().set_tag(true); - } - robin_hood(bucket, disp, self.hash, self.key, value) - }, - NoElem(mut bucket, disp) => { - if disp >= DISPLACEMENT_THRESHOLD { - bucket.table_mut().set_tag(true); - } - bucket.put(self.hash, self.key, value) - }, - }; - b.into_mut_refs().1 - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V, S> FromIterator<(K, V)> for HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher + Default -{ - fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> HashMap<K, V, S> { - let mut map = HashMap::with_hasher(Default::default()); - map.extend(iter); - map - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K, V, S> Extend<(K, V)> for HashMap<K, V, S> - where K: Eq + Hash, - S: BuildHasher -{ - fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T) { - // Keys may be already present or show multiple times in the iterator. - // Reserve the entire hint lower bound if the map is empty. - // Otherwise reserve half the hint (rounded up), so the map - // will only resize twice in the worst case. - let iter = iter.into_iter(); - let reserve = if self.is_empty() { - iter.size_hint().0 - } else { - (iter.size_hint().0 + 1) / 2 - }; - self.reserve(reserve); - for (k, v) in iter { - self.insert(k, v); - } - } -} - -#[stable(feature = "hash_extend_copy", since = "1.4.0")] -impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S> - where K: Eq + Hash + Copy, - V: Copy, - S: BuildHasher -{ - fn extend<T: IntoIterator<Item = (&'a K, &'a V)>>(&mut self, iter: T) { - self.extend(iter.into_iter().map(|(&key, &value)| (key, value))); - } -} - -/// `RandomState` is the default state for [`HashMap`] types. -/// -/// A particular instance `RandomState` will create the same instances of -/// [`Hasher`], but the hashers created by two different `RandomState` -/// instances are unlikely to produce the same result for the same values. -/// -/// [`HashMap`]: struct.HashMap.html -/// [`Hasher`]: ../../hash/trait.Hasher.html -/// -/// # Examples -/// -/// ``` -/// use std::collections::HashMap; -/// use std::collections::hash_map::RandomState; -/// -/// let s = RandomState::new(); -/// let mut map = HashMap::with_hasher(s); -/// map.insert(1, 2); -/// ``` -#[derive(Clone)] -#[stable(feature = "hashmap_build_hasher", since = "1.7.0")] -pub struct RandomState { - k0: u64, - k1: u64, -} - -impl RandomState { - /// Constructs a new `RandomState` that is initialized with random keys. - /// - /// # Examples - /// - /// ``` - /// use std::collections::hash_map::RandomState; - /// - /// let s = RandomState::new(); - /// ``` - #[inline] - #[allow(deprecated)] - // rand - #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] - pub fn new() -> RandomState { - // Historically this function did not cache keys from the OS and instead - // simply always called `rand::thread_rng().gen()` twice. In #31356 it - // was discovered, however, that because we re-seed the thread-local RNG - // from the OS periodically that this can cause excessive slowdown when - // many hash maps are created on a thread. To solve this performance - // trap we cache the first set of randomly generated keys per-thread. - // - // Later in #36481 it was discovered that exposing a deterministic - // iteration order allows a form of DOS attack. To counter that we - // increment one of the seeds on every RandomState creation, giving - // every corresponding HashMap a different iteration order. - thread_local!(static KEYS: Cell<(u64, u64)> = { - Cell::new(sys::hashmap_random_keys()) - }); - - KEYS.with(|keys| { - let (k0, k1) = keys.get(); - keys.set((k0.wrapping_add(1), k1)); - RandomState { k0: k0, k1: k1 } - }) - } -} - -#[stable(feature = "hashmap_build_hasher", since = "1.7.0")] -impl BuildHasher for RandomState { - type Hasher = DefaultHasher; - #[inline] - #[allow(deprecated)] - fn build_hasher(&self) -> DefaultHasher { - DefaultHasher(SipHasher13::new_with_keys(self.k0, self.k1)) - } -} - -/// The default [`Hasher`] used by [`RandomState`]. -/// -/// The internal algorithm is not specified, and so it and its hashes should -/// not be relied upon over releases. -/// -/// [`RandomState`]: struct.RandomState.html -/// [`Hasher`]: ../../hash/trait.Hasher.html -#[stable(feature = "hashmap_default_hasher", since = "1.13.0")] -#[allow(deprecated)] -#[derive(Clone, Debug)] -pub struct DefaultHasher(SipHasher13); - -impl DefaultHasher { - /// Creates a new `DefaultHasher`. - /// - /// This hasher is not guaranteed to be the same as all other - /// `DefaultHasher` instances, but is the same as all other `DefaultHasher` - /// instances created through `new` or `default`. - #[stable(feature = "hashmap_default_hasher", since = "1.13.0")] - #[allow(deprecated)] - pub fn new() -> DefaultHasher { - DefaultHasher(SipHasher13::new_with_keys(0, 0)) - } -} - -#[stable(feature = "hashmap_default_hasher", since = "1.13.0")] -impl Default for DefaultHasher { - /// Creates a new `DefaultHasher` using [`new`]. See its documentation for more. - /// - /// [`new`]: #method.new - fn default() -> DefaultHasher { - DefaultHasher::new() - } -} - -#[stable(feature = "hashmap_default_hasher", since = "1.13.0")] -impl Hasher for DefaultHasher { - #[inline] - fn write(&mut self, msg: &[u8]) { - self.0.write(msg) - } - - #[inline] - fn finish(&self) -> u64 { - self.0.finish() - } -} - -#[stable(feature = "hashmap_build_hasher", since = "1.7.0")] -impl Default for RandomState { - /// Constructs a new `RandomState`. - #[inline] - fn default() -> RandomState { - RandomState::new() - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl fmt::Debug for RandomState { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.pad("RandomState { .. }") - } -} - -impl<K, S, Q: ?Sized> super::Recover<Q> for HashMap<K, (), S> - where K: Eq + Hash + Borrow<Q>, - S: BuildHasher, - Q: Eq + Hash -{ - type Key = K; - - #[inline] - fn get(&self, key: &Q) -> Option<&K> { - self.search(key).map(|bucket| bucket.into_refs().0) - } - - fn take(&mut self, key: &Q) -> Option<K> { - self.search_mut(key).map(|bucket| pop_internal(bucket).0) - } - - #[inline] - fn replace(&mut self, key: K) -> Option<K> { - self.reserve(1); - - match self.entry(key) { - Occupied(mut occupied) => { - let key = occupied.take_key().unwrap(); - Some(mem::replace(occupied.elem.read_mut().0, key)) - } - Vacant(vacant) => { - vacant.insert(()); - None - } - } - } -} - -#[allow(dead_code)] -fn assert_covariance() { - fn map_key<'new>(v: HashMap<&'static str, u8>) -> HashMap<&'new str, u8> { - v - } - fn map_val<'new>(v: HashMap<u8, &'static str>) -> HashMap<u8, &'new str> { - v - } - fn iter_key<'a, 'new>(v: Iter<'a, &'static str, u8>) -> Iter<'a, &'new str, u8> { - v - } - fn iter_val<'a, 'new>(v: Iter<'a, u8, &'static str>) -> Iter<'a, u8, &'new str> { - v - } - fn into_iter_key<'new>(v: IntoIter<&'static str, u8>) -> IntoIter<&'new str, u8> { - v - } - fn into_iter_val<'new>(v: IntoIter<u8, &'static str>) -> IntoIter<u8, &'new str> { - v - } - fn keys_key<'a, 'new>(v: Keys<'a, &'static str, u8>) -> Keys<'a, &'new str, u8> { - v - } - fn keys_val<'a, 'new>(v: Keys<'a, u8, &'static str>) -> Keys<'a, u8, &'new str> { - v - } - fn values_key<'a, 'new>(v: Values<'a, &'static str, u8>) -> Values<'a, &'new str, u8> { - v - } - fn values_val<'a, 'new>(v: Values<'a, u8, &'static str>) -> Values<'a, u8, &'new str> { - v - } - fn drain<'new>(d: Drain<'static, &'static str, &'static str>) - -> Drain<'new, &'new str, &'new str> { - d - } -} - -#[cfg(test)] -mod test_map { - use super::HashMap; - use super::Entry::{Occupied, Vacant}; - use super::RandomState; - use cell::RefCell; - use rand::{thread_rng, Rng}; - use realstd::collections::CollectionAllocErr::*; - use realstd::mem::size_of; - use realstd::usize; - - #[test] - fn test_zero_capacities() { - type HM = HashMap<i32, i32>; - - let m = HM::new(); - assert_eq!(m.capacity(), 0); - - let m = HM::default(); - assert_eq!(m.capacity(), 0); - - let m = HM::with_hasher(RandomState::new()); - assert_eq!(m.capacity(), 0); - - let m = HM::with_capacity(0); - assert_eq!(m.capacity(), 0); - - let m = HM::with_capacity_and_hasher(0, RandomState::new()); - assert_eq!(m.capacity(), 0); - - let mut m = HM::new(); - m.insert(1, 1); - m.insert(2, 2); - m.remove(&1); - m.remove(&2); - m.shrink_to_fit(); - assert_eq!(m.capacity(), 0); - - let mut m = HM::new(); - m.reserve(0); - assert_eq!(m.capacity(), 0); - } - - #[test] - fn test_create_capacity_zero() { - let mut m = HashMap::with_capacity(0); - - assert!(m.insert(1, 1).is_none()); - - assert!(m.contains_key(&1)); - assert!(!m.contains_key(&0)); - } - - #[test] - fn test_insert() { - let mut m = HashMap::new(); - assert_eq!(m.len(), 0); - assert!(m.insert(1, 2).is_none()); - assert_eq!(m.len(), 1); - assert!(m.insert(2, 4).is_none()); - assert_eq!(m.len(), 2); - assert_eq!(*m.get(&1).unwrap(), 2); - assert_eq!(*m.get(&2).unwrap(), 4); - } - - #[test] - fn test_clone() { - let mut m = HashMap::new(); - assert_eq!(m.len(), 0); - assert!(m.insert(1, 2).is_none()); - assert_eq!(m.len(), 1); - assert!(m.insert(2, 4).is_none()); - assert_eq!(m.len(), 2); - let m2 = m.clone(); - assert_eq!(*m2.get(&1).unwrap(), 2); - assert_eq!(*m2.get(&2).unwrap(), 4); - assert_eq!(m2.len(), 2); - } - - thread_local! { static DROP_VECTOR: RefCell<Vec<i32>> = RefCell::new(Vec::new()) } - - #[derive(Hash, PartialEq, Eq)] - struct Droppable { - k: usize, - } - - impl Droppable { - fn new(k: usize) -> Droppable { - DROP_VECTOR.with(|slot| { - slot.borrow_mut()[k] += 1; - }); - - Droppable { k: k } - } - } - - impl Drop for Droppable { - fn drop(&mut self) { - DROP_VECTOR.with(|slot| { - slot.borrow_mut()[self.k] -= 1; - }); - } - } - - impl Clone for Droppable { - fn clone(&self) -> Droppable { - Droppable::new(self.k) - } - } - - #[test] - fn test_drops() { - DROP_VECTOR.with(|slot| { - *slot.borrow_mut() = vec![0; 200]; - }); - - { - let mut m = HashMap::new(); - - DROP_VECTOR.with(|v| { - for i in 0..200 { - assert_eq!(v.borrow()[i], 0); - } - }); - - for i in 0..100 { - let d1 = Droppable::new(i); - let d2 = Droppable::new(i + 100); - m.insert(d1, d2); - } - - DROP_VECTOR.with(|v| { - for i in 0..200 { - assert_eq!(v.borrow()[i], 1); - } - }); - - for i in 0..50 { - let k = Droppable::new(i); - let v = m.remove(&k); - - assert!(v.is_some()); - - DROP_VECTOR.with(|v| { - assert_eq!(v.borrow()[i], 1); - assert_eq!(v.borrow()[i+100], 1); - }); - } - - DROP_VECTOR.with(|v| { - for i in 0..50 { - assert_eq!(v.borrow()[i], 0); - assert_eq!(v.borrow()[i+100], 0); - } - - for i in 50..100 { - assert_eq!(v.borrow()[i], 1); - assert_eq!(v.borrow()[i+100], 1); - } - }); - } - - DROP_VECTOR.with(|v| { - for i in 0..200 { - assert_eq!(v.borrow()[i], 0); - } - }); - } - - #[test] - fn test_into_iter_drops() { - DROP_VECTOR.with(|v| { - *v.borrow_mut() = vec![0; 200]; - }); - - let hm = { - let mut hm = HashMap::new(); - - DROP_VECTOR.with(|v| { - for i in 0..200 { - assert_eq!(v.borrow()[i], 0); - } - }); - - for i in 0..100 { - let d1 = Droppable::new(i); - let d2 = Droppable::new(i + 100); - hm.insert(d1, d2); - } - - DROP_VECTOR.with(|v| { - for i in 0..200 { - assert_eq!(v.borrow()[i], 1); - } - }); - - hm - }; - - // By the way, ensure that cloning doesn't screw up the dropping. - drop(hm.clone()); - - { - let mut half = hm.into_iter().take(50); - - DROP_VECTOR.with(|v| { - for i in 0..200 { - assert_eq!(v.borrow()[i], 1); - } - }); - - for _ in half.by_ref() {} - - DROP_VECTOR.with(|v| { - let nk = (0..100) - .filter(|&i| v.borrow()[i] == 1) - .count(); - - let nv = (0..100) - .filter(|&i| v.borrow()[i + 100] == 1) - .count(); - - assert_eq!(nk, 50); - assert_eq!(nv, 50); - }); - }; - - DROP_VECTOR.with(|v| { - for i in 0..200 { - assert_eq!(v.borrow()[i], 0); - } - }); - } - - #[test] - fn test_empty_remove() { - let mut m: HashMap<i32, bool> = HashMap::new(); - assert_eq!(m.remove(&0), None); - } - - #[test] - fn test_empty_entry() { - let mut m: HashMap<i32, bool> = HashMap::new(); - match m.entry(0) { - Occupied(_) => panic!(), - Vacant(_) => {} - } - assert!(*m.entry(0).or_insert(true)); - assert_eq!(m.len(), 1); - } - - #[test] - fn test_empty_iter() { - let mut m: HashMap<i32, bool> = HashMap::new(); - assert_eq!(m.drain().next(), None); - assert_eq!(m.keys().next(), None); - assert_eq!(m.values().next(), None); - assert_eq!(m.values_mut().next(), None); - assert_eq!(m.iter().next(), None); - assert_eq!(m.iter_mut().next(), None); - assert_eq!(m.len(), 0); - assert!(m.is_empty()); - assert_eq!(m.into_iter().next(), None); - } - - #[test] - fn test_lots_of_insertions() { - let mut m = HashMap::new(); - - // Try this a few times to make sure we never screw up the hashmap's - // internal state. - for _ in 0..10 { - assert!(m.is_empty()); - - for i in 1..1001 { - assert!(m.insert(i, i).is_none()); - - for j in 1..i + 1 { - let r = m.get(&j); - assert_eq!(r, Some(&j)); - } - - for j in i + 1..1001 { - let r = m.get(&j); - assert_eq!(r, None); - } - } - - for i in 1001..2001 { - assert!(!m.contains_key(&i)); - } - - // remove forwards - for i in 1..1001 { - assert!(m.remove(&i).is_some()); - - for j in 1..i + 1 { - assert!(!m.contains_key(&j)); - } - - for j in i + 1..1001 { - assert!(m.contains_key(&j)); - } - } - - for i in 1..1001 { - assert!(!m.contains_key(&i)); - } - - for i in 1..1001 { - assert!(m.insert(i, i).is_none()); - } - - // remove backwards - for i in (1..1001).rev() { - assert!(m.remove(&i).is_some()); - - for j in i..1001 { - assert!(!m.contains_key(&j)); - } - - for j in 1..i { - assert!(m.contains_key(&j)); - } - } - } - } - - #[test] - fn test_find_mut() { - let mut m = HashMap::new(); - assert!(m.insert(1, 12).is_none()); - assert!(m.insert(2, 8).is_none()); - assert!(m.insert(5, 14).is_none()); - let new = 100; - match m.get_mut(&5) { - None => panic!(), - Some(x) => *x = new, - } - assert_eq!(m.get(&5), Some(&new)); - } - - #[test] - fn test_insert_overwrite() { - let mut m = HashMap::new(); - assert!(m.insert(1, 2).is_none()); - assert_eq!(*m.get(&1).unwrap(), 2); - assert!(!m.insert(1, 3).is_none()); - assert_eq!(*m.get(&1).unwrap(), 3); - } - - #[test] - fn test_insert_conflicts() { - let mut m = HashMap::with_capacity(4); - assert!(m.insert(1, 2).is_none()); - assert!(m.insert(5, 3).is_none()); - assert!(m.insert(9, 4).is_none()); - assert_eq!(*m.get(&9).unwrap(), 4); - assert_eq!(*m.get(&5).unwrap(), 3); - assert_eq!(*m.get(&1).unwrap(), 2); - } - - #[test] - fn test_conflict_remove() { - let mut m = HashMap::with_capacity(4); - assert!(m.insert(1, 2).is_none()); - assert_eq!(*m.get(&1).unwrap(), 2); - assert!(m.insert(5, 3).is_none()); - assert_eq!(*m.get(&1).unwrap(), 2); - assert_eq!(*m.get(&5).unwrap(), 3); - assert!(m.insert(9, 4).is_none()); - assert_eq!(*m.get(&1).unwrap(), 2); - assert_eq!(*m.get(&5).unwrap(), 3); - assert_eq!(*m.get(&9).unwrap(), 4); - assert!(m.remove(&1).is_some()); - assert_eq!(*m.get(&9).unwrap(), 4); - assert_eq!(*m.get(&5).unwrap(), 3); - } - - #[test] - fn test_is_empty() { - let mut m = HashMap::with_capacity(4); - assert!(m.insert(1, 2).is_none()); - assert!(!m.is_empty()); - assert!(m.remove(&1).is_some()); - assert!(m.is_empty()); - } - - #[test] - fn test_remove() { - let mut m = HashMap::new(); - m.insert(1, 2); - assert_eq!(m.remove(&1), Some(2)); - assert_eq!(m.remove(&1), None); - } - - #[test] - fn test_remove_entry() { - let mut m = HashMap::new(); - m.insert(1, 2); - assert_eq!(m.remove_entry(&1), Some((1, 2))); - assert_eq!(m.remove(&1), None); - } - - #[test] - fn test_iterate() { - let mut m = HashMap::with_capacity(4); - for i in 0..32 { - assert!(m.insert(i, i*2).is_none()); - } - assert_eq!(m.len(), 32); - - let mut observed: u32 = 0; - - for (k, v) in &m { - assert_eq!(*v, *k * 2); - observed |= 1 << *k; - } - assert_eq!(observed, 0xFFFF_FFFF); - } - - #[test] - fn test_keys() { - let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')]; - let map: HashMap<_, _> = vec.into_iter().collect(); - let keys: Vec<_> = map.keys().cloned().collect(); - assert_eq!(keys.len(), 3); - assert!(keys.contains(&1)); - assert!(keys.contains(&2)); - assert!(keys.contains(&3)); - } - - #[test] - fn test_values() { - let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')]; - let map: HashMap<_, _> = vec.into_iter().collect(); - let values: Vec<_> = map.values().cloned().collect(); - assert_eq!(values.len(), 3); - assert!(values.contains(&'a')); - assert!(values.contains(&'b')); - assert!(values.contains(&'c')); - } - - #[test] - fn test_values_mut() { - let vec = vec![(1, 1), (2, 2), (3, 3)]; - let mut map: HashMap<_, _> = vec.into_iter().collect(); - for value in map.values_mut() { - *value = (*value) * 2 - } - let values: Vec<_> = map.values().cloned().collect(); - assert_eq!(values.len(), 3); - assert!(values.contains(&2)); - assert!(values.contains(&4)); - assert!(values.contains(&6)); - } - - #[test] - fn test_find() { - let mut m = HashMap::new(); - assert!(m.get(&1).is_none()); - m.insert(1, 2); - match m.get(&1) { - None => panic!(), - Some(v) => assert_eq!(*v, 2), - } - } - - #[test] - fn test_eq() { - let mut m1 = HashMap::new(); - m1.insert(1, 2); - m1.insert(2, 3); - m1.insert(3, 4); - - let mut m2 = HashMap::new(); - m2.insert(1, 2); - m2.insert(2, 3); - - assert!(m1 != m2); - - m2.insert(3, 4); - - assert_eq!(m1, m2); - } - - #[test] - fn test_show() { - let mut map = HashMap::new(); - let empty: HashMap<i32, i32> = HashMap::new(); - - map.insert(1, 2); - map.insert(3, 4); - - let map_str = format!("{:?}", map); - - assert!(map_str == "{1: 2, 3: 4}" || - map_str == "{3: 4, 1: 2}"); - assert_eq!(format!("{:?}", empty), "{}"); - } - - #[test] - fn test_expand() { - let mut m = HashMap::new(); - - assert_eq!(m.len(), 0); - assert!(m.is_empty()); - - let mut i = 0; - let old_raw_cap = m.raw_capacity(); - while old_raw_cap == m.raw_capacity() { - m.insert(i, i); - i += 1; - } - - assert_eq!(m.len(), i); - assert!(!m.is_empty()); - } - - #[test] - fn test_behavior_resize_policy() { - let mut m = HashMap::new(); - - assert_eq!(m.len(), 0); - assert_eq!(m.raw_capacity(), 0); - assert!(m.is_empty()); - - m.insert(0, 0); - m.remove(&0); - assert!(m.is_empty()); - let initial_raw_cap = m.raw_capacity(); - m.reserve(initial_raw_cap); - let raw_cap = m.raw_capacity(); - - assert_eq!(raw_cap, initial_raw_cap * 2); - - let mut i = 0; - for _ in 0..raw_cap * 3 / 4 { - m.insert(i, i); - i += 1; - } - // three quarters full - - assert_eq!(m.len(), i); - assert_eq!(m.raw_capacity(), raw_cap); - - for _ in 0..raw_cap / 4 { - m.insert(i, i); - i += 1; - } - // half full - - let new_raw_cap = m.raw_capacity(); - assert_eq!(new_raw_cap, raw_cap * 2); - - for _ in 0..raw_cap / 2 - 1 { - i -= 1; - m.remove(&i); - assert_eq!(m.raw_capacity(), new_raw_cap); - } - // A little more than one quarter full. - m.shrink_to_fit(); - assert_eq!(m.raw_capacity(), raw_cap); - // again, a little more than half full - for _ in 0..raw_cap / 2 - 1 { - i -= 1; - m.remove(&i); - } - m.shrink_to_fit(); - - assert_eq!(m.len(), i); - assert!(!m.is_empty()); - assert_eq!(m.raw_capacity(), initial_raw_cap); - } - - #[test] - fn test_reserve_shrink_to_fit() { - let mut m = HashMap::new(); - m.insert(0, 0); - m.remove(&0); - assert!(m.capacity() >= m.len()); - for i in 0..128 { - m.insert(i, i); - } - m.reserve(256); - - let usable_cap = m.capacity(); - for i in 128..(128 + 256) { - m.insert(i, i); - assert_eq!(m.capacity(), usable_cap); - } - - for i in 100..(128 + 256) { - assert_eq!(m.remove(&i), Some(i)); - } - m.shrink_to_fit(); - - assert_eq!(m.len(), 100); - assert!(!m.is_empty()); - assert!(m.capacity() >= m.len()); - - for i in 0..100 { - assert_eq!(m.remove(&i), Some(i)); - } - m.shrink_to_fit(); - m.insert(0, 0); - - assert_eq!(m.len(), 1); - assert!(m.capacity() >= m.len()); - assert_eq!(m.remove(&0), Some(0)); - } - - #[test] - fn test_from_iter() { - let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let map: HashMap<_, _> = xs.iter().cloned().collect(); - - for &(k, v) in &xs { - assert_eq!(map.get(&k), Some(&v)); - } - } - - #[test] - fn test_size_hint() { - let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let map: HashMap<_, _> = xs.iter().cloned().collect(); - - let mut iter = map.iter(); - - for _ in iter.by_ref().take(3) {} - - assert_eq!(iter.size_hint(), (3, Some(3))); - } - - #[test] - fn test_iter_len() { - let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let map: HashMap<_, _> = xs.iter().cloned().collect(); - - let mut iter = map.iter(); - - for _ in iter.by_ref().take(3) {} - - assert_eq!(iter.len(), 3); - } - - #[test] - fn test_mut_size_hint() { - let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let mut map: HashMap<_, _> = xs.iter().cloned().collect(); - - let mut iter = map.iter_mut(); - - for _ in iter.by_ref().take(3) {} - - assert_eq!(iter.size_hint(), (3, Some(3))); - } - - #[test] - fn test_iter_mut_len() { - let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let mut map: HashMap<_, _> = xs.iter().cloned().collect(); - - let mut iter = map.iter_mut(); - - for _ in iter.by_ref().take(3) {} - - assert_eq!(iter.len(), 3); - } - - #[test] - fn test_index() { - let mut map = HashMap::new(); - - map.insert(1, 2); - map.insert(2, 1); - map.insert(3, 4); - - assert_eq!(map[&2], 1); - } - - #[test] - #[should_panic] - fn test_index_nonexistent() { - let mut map = HashMap::new(); - - map.insert(1, 2); - map.insert(2, 1); - map.insert(3, 4); - - map[&4]; - } - - #[test] - fn test_entry() { - let xs = [(1, 10), (2, 20), (3, 30), (4, 40), (5, 50), (6, 60)]; - - let mut map: HashMap<_, _> = xs.iter().cloned().collect(); - - // Existing key (insert) - match map.entry(1) { - Vacant(_) => unreachable!(), - Occupied(mut view) => { - assert_eq!(view.get(), &10); - assert_eq!(view.insert(100), 10); - } - } - assert_eq!(map.get(&1).unwrap(), &100); - assert_eq!(map.len(), 6); - - - // Existing key (update) - match map.entry(2) { - Vacant(_) => unreachable!(), - Occupied(mut view) => { - let v = view.get_mut(); - let new_v = (*v) * 10; - *v = new_v; - } - } - assert_eq!(map.get(&2).unwrap(), &200); - assert_eq!(map.len(), 6); - - // Existing key (take) - match map.entry(3) { - Vacant(_) => unreachable!(), - Occupied(view) => { - assert_eq!(view.remove(), 30); - } - } - assert_eq!(map.get(&3), None); - assert_eq!(map.len(), 5); - - - // Inexistent key (insert) - match map.entry(10) { - Occupied(_) => unreachable!(), - Vacant(view) => { - assert_eq!(*view.insert(1000), 1000); - } - } - assert_eq!(map.get(&10).unwrap(), &1000); - assert_eq!(map.len(), 6); - } - - #[test] - fn test_entry_take_doesnt_corrupt() { - #![allow(deprecated)] //rand - // Test for #19292 - fn check(m: &HashMap<i32, ()>) { - for k in m.keys() { - assert!(m.contains_key(k), - "{} is in keys() but not in the map?", k); - } - } - - let mut m = HashMap::new(); - let mut rng = thread_rng(); - - // Populate the map with some items. - for _ in 0..50 { - let x = rng.gen_range(-10, 10); - m.insert(x, ()); - } - - for i in 0..1000 { - let x = rng.gen_range(-10, 10); - match m.entry(x) { - Vacant(_) => {} - Occupied(e) => { - println!("{}: remove {}", i, x); - e.remove(); - } - } - - check(&m); - } - } - - #[test] - fn test_extend_ref() { - let mut a = HashMap::new(); - a.insert(1, "one"); - let mut b = HashMap::new(); - b.insert(2, "two"); - b.insert(3, "three"); - - a.extend(&b); - - assert_eq!(a.len(), 3); - assert_eq!(a[&1], "one"); - assert_eq!(a[&2], "two"); - assert_eq!(a[&3], "three"); - } - - #[test] - fn test_capacity_not_less_than_len() { - let mut a = HashMap::new(); - let mut item = 0; - - for _ in 0..116 { - a.insert(item, 0); - item += 1; - } - - assert!(a.capacity() > a.len()); - - let free = a.capacity() - a.len(); - for _ in 0..free { - a.insert(item, 0); - item += 1; - } - - assert_eq!(a.len(), a.capacity()); - - // Insert at capacity should cause allocation. - a.insert(item, 0); - assert!(a.capacity() > a.len()); - } - - #[test] - fn test_occupied_entry_key() { - let mut a = HashMap::new(); - let key = "hello there"; - let value = "value goes here"; - assert!(a.is_empty()); - a.insert(key.clone(), value.clone()); - assert_eq!(a.len(), 1); - assert_eq!(a[key], value); - - match a.entry(key.clone()) { - Vacant(_) => panic!(), - Occupied(e) => assert_eq!(key, *e.key()), - } - assert_eq!(a.len(), 1); - assert_eq!(a[key], value); - } - - #[test] - fn test_vacant_entry_key() { - let mut a = HashMap::new(); - let key = "hello there"; - let value = "value goes here"; - - assert!(a.is_empty()); - match a.entry(key.clone()) { - Occupied(_) => panic!(), - Vacant(e) => { - assert_eq!(key, *e.key()); - e.insert(value.clone()); - } - } - assert_eq!(a.len(), 1); - assert_eq!(a[key], value); - } - - #[test] - fn test_retain() { - let mut map: HashMap<i32, i32> = (0..100).map(|x|(x, x*10)).collect(); - - map.retain(|&k, _| k % 2 == 0); - assert_eq!(map.len(), 50); - assert_eq!(map[&2], 20); - assert_eq!(map[&4], 40); - assert_eq!(map[&6], 60); - } - - #[test] - fn test_adaptive() { - const TEST_LEN: usize = 5000; - // by cloning we get maps with the same hasher seed - let mut first = HashMap::new(); - let mut second = first.clone(); - first.extend((0..TEST_LEN).map(|i| (i, i))); - second.extend((TEST_LEN..TEST_LEN * 2).map(|i| (i, i))); - - for (&k, &v) in &second { - let prev_cap = first.capacity(); - let expect_grow = first.len() == prev_cap; - first.insert(k, v); - if !expect_grow && first.capacity() != prev_cap { - return; - } - } - panic!("Adaptive early resize failed"); - } - - #[test] - fn test_try_reserve() { - - let mut empty_bytes: HashMap<u8,u8> = HashMap::new(); - - const MAX_USIZE: usize = usize::MAX; - - // HashMap and RawTables use complicated size calculations - // hashes_size is sizeof(HashUint) * capacity; - // pairs_size is sizeof((K. V)) * capacity; - // alignment_hashes_size is 8 - // alignment_pairs size is 4 - let size_of_multiplier = (size_of::<usize>() + size_of::<(u8, u8)>()).next_power_of_two(); - // The following formula is used to calculate the new capacity - let max_no_ovf = ((MAX_USIZE / 11) * 10) / size_of_multiplier - 1; - - if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_USIZE) { - } else { panic!("usize::MAX should trigger an overflow!"); } - - if size_of::<usize>() < 8 { - if let Err(CapacityOverflow) = empty_bytes.try_reserve(max_no_ovf) { - } else { panic!("isize::MAX + 1 should trigger a CapacityOverflow!") } - } else { - if let Err(AllocErr) = empty_bytes.try_reserve(max_no_ovf) { - } else { panic!("isize::MAX + 1 should trigger an OOM!") } - } - } - -} diff --git a/ctr-std/src/collections/hash/mod.rs b/ctr-std/src/collections/hash/mod.rs deleted file mode 100644 index 7a22bec..0000000 --- a/ctr-std/src/collections/hash/mod.rs +++ /dev/null @@ -1,24 +0,0 @@ -// Copyright 2014 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -//! Unordered containers, implemented as hash-tables - -mod bench; -mod table; -pub mod map; -pub mod set; - -trait Recover<Q: ?Sized> { - type Key; - - fn get(&self, key: &Q) -> Option<&Self::Key>; - fn take(&mut self, key: &Q) -> Option<Self::Key>; - fn replace(&mut self, key: Self::Key) -> Option<Self::Key>; -} diff --git a/ctr-std/src/collections/hash/set.rs b/ctr-std/src/collections/hash/set.rs deleted file mode 100644 index 5ac3e8f..0000000 --- a/ctr-std/src/collections/hash/set.rs +++ /dev/null @@ -1,1783 +0,0 @@ -// Copyright 2014 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -use borrow::Borrow; -use fmt; -use hash::{Hash, BuildHasher}; -use iter::{Chain, FromIterator, FusedIterator}; -use ops::{BitOr, BitAnd, BitXor, Sub}; - -use super::Recover; -use super::map::{self, HashMap, Keys, RandomState}; - -// Future Optimization (FIXME!) -// ============================= -// -// Iteration over zero sized values is a noop. There is no need -// for `bucket.val` in the case of HashSet. I suppose we would need HKT -// to get rid of it properly. - -/// A hash set implemented as a `HashMap` where the value is `()`. -/// -/// As with the [`HashMap`] type, a `HashSet` requires that the elements -/// implement the [`Eq`] and [`Hash`] traits. This can frequently be achieved by -/// using `#[derive(PartialEq, Eq, Hash)]`. If you implement these yourself, -/// it is important that the following property holds: -/// -/// ```text -/// k1 == k2 -> hash(k1) == hash(k2) -/// ``` -/// -/// In other words, if two keys are equal, their hashes must be equal. -/// -/// -/// It is a logic error for an item to be modified in such a way that the -/// item's hash, as determined by the [`Hash`] trait, or its equality, as -/// determined by the [`Eq`] trait, changes while it is in the set. This is -/// normally only possible through [`Cell`], [`RefCell`], global state, I/O, or -/// unsafe code. -/// -/// # Examples -/// -/// ``` -/// use std::collections::HashSet; -/// // Type inference lets us omit an explicit type signature (which -/// // would be `HashSet<String>` in this example). -/// let mut books = HashSet::new(); -/// -/// // Add some books. -/// books.insert("A Dance With Dragons".to_string()); -/// books.insert("To Kill a Mockingbird".to_string()); -/// books.insert("The Odyssey".to_string()); -/// books.insert("The Great Gatsby".to_string()); -/// -/// // Check for a specific one. -/// if !books.contains("The Winds of Winter") { -/// println!("We have {} books, but The Winds of Winter ain't one.", -/// books.len()); -/// } -/// -/// // Remove a book. -/// books.remove("The Odyssey"); -/// -/// // Iterate over everything. -/// for book in &books { -/// println!("{}", book); -/// } -/// ``` -/// -/// The easiest way to use `HashSet` with a custom type is to derive -/// [`Eq`] and [`Hash`]. We must also derive [`PartialEq`], this will in the -/// future be implied by [`Eq`]. -/// -/// ``` -/// use std::collections::HashSet; -/// #[derive(Hash, Eq, PartialEq, Debug)] -/// struct Viking { -/// name: String, -/// power: usize, -/// } -/// -/// let mut vikings = HashSet::new(); -/// -/// vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); -/// vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); -/// vikings.insert(Viking { name: "Olaf".to_string(), power: 4 }); -/// vikings.insert(Viking { name: "Harald".to_string(), power: 8 }); -/// -/// // Use derived implementation to print the vikings. -/// for x in &vikings { -/// println!("{:?}", x); -/// } -/// ``` -/// -/// A `HashSet` with fixed list of elements can be initialized from an array: -/// -/// ``` -/// use std::collections::HashSet; -/// -/// fn main() { -/// let viking_names: HashSet<&'static str> = -/// [ "Einar", "Olaf", "Harald" ].iter().cloned().collect(); -/// // use the values stored in the set -/// } -/// ``` -/// -/// [`Cell`]: ../../std/cell/struct.Cell.html -/// [`Eq`]: ../../std/cmp/trait.Eq.html -/// [`Hash`]: ../../std/hash/trait.Hash.html -/// [`HashMap`]: struct.HashMap.html -/// [`PartialEq`]: ../../std/cmp/trait.PartialEq.html -/// [`RefCell`]: ../../std/cell/struct.RefCell.html -#[derive(Clone)] -#[stable(feature = "rust1", since = "1.0.0")] -pub struct HashSet<T, S = RandomState> { - map: HashMap<T, (), S>, -} - -impl<T: Hash + Eq> HashSet<T, RandomState> { - /// Creates an empty `HashSet`. - /// - /// The hash set is initially created with a capacity of 0, so it will not allocate until it - /// is first inserted into. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let set: HashSet<i32> = HashSet::new(); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn new() -> HashSet<T, RandomState> { - HashSet { map: HashMap::new() } - } - - /// Creates an empty `HashSet` with the specified capacity. - /// - /// The hash set will be able to hold at least `capacity` elements without - /// reallocating. If `capacity` is 0, the hash set will not allocate. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let set: HashSet<i32> = HashSet::with_capacity(10); - /// assert!(set.capacity() >= 10); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn with_capacity(capacity: usize) -> HashSet<T, RandomState> { - HashSet { map: HashMap::with_capacity(capacity) } - } -} - -impl<T, S> HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher -{ - /// Creates a new empty hash set which will use the given hasher to hash - /// keys. - /// - /// The hash set is also created with the default initial capacity. - /// - /// Warning: `hasher` is normally randomly generated, and - /// is designed to allow `HashSet`s to be resistant to attacks that - /// cause many collisions and very poor performance. Setting it - /// manually using this function can expose a DoS attack vector. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// use std::collections::hash_map::RandomState; - /// - /// let s = RandomState::new(); - /// let mut set = HashSet::with_hasher(s); - /// set.insert(2); - /// ``` - #[inline] - #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] - pub fn with_hasher(hasher: S) -> HashSet<T, S> { - HashSet { map: HashMap::with_hasher(hasher) } - } - - /// Creates an empty `HashSet` with with the specified capacity, using - /// `hasher` to hash the keys. - /// - /// The hash set will be able to hold at least `capacity` elements without - /// reallocating. If `capacity` is 0, the hash set will not allocate. - /// - /// Warning: `hasher` is normally randomly generated, and - /// is designed to allow `HashSet`s to be resistant to attacks that - /// cause many collisions and very poor performance. Setting it - /// manually using this function can expose a DoS attack vector. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// use std::collections::hash_map::RandomState; - /// - /// let s = RandomState::new(); - /// let mut set = HashSet::with_capacity_and_hasher(10, s); - /// set.insert(1); - /// ``` - #[inline] - #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] - pub fn with_capacity_and_hasher(capacity: usize, hasher: S) -> HashSet<T, S> { - HashSet { map: HashMap::with_capacity_and_hasher(capacity, hasher) } - } - - /// Returns a reference to the set's [`BuildHasher`]. - /// - /// [`BuildHasher`]: ../../std/hash/trait.BuildHasher.html - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// use std::collections::hash_map::RandomState; - /// - /// let hasher = RandomState::new(); - /// let set: HashSet<i32> = HashSet::with_hasher(hasher); - /// let hasher: &RandomState = set.hasher(); - /// ``` - #[stable(feature = "hashmap_public_hasher", since = "1.9.0")] - pub fn hasher(&self) -> &S { - self.map.hasher() - } - - /// Returns the number of elements the set can hold without reallocating. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let set: HashSet<i32> = HashSet::with_capacity(100); - /// assert!(set.capacity() >= 100); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn capacity(&self) -> usize { - self.map.capacity() - } - - /// Reserves capacity for at least `additional` more elements to be inserted - /// in the `HashSet`. The collection may reserve more space to avoid - /// frequent reallocations. - /// - /// # Panics - /// - /// Panics if the new allocation size overflows `usize`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let mut set: HashSet<i32> = HashSet::new(); - /// set.reserve(10); - /// assert!(set.capacity() >= 10); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn reserve(&mut self, additional: usize) { - self.map.reserve(additional) - } - - /// Shrinks the capacity of the set as much as possible. It will drop - /// down as much as possible while maintaining the internal rules - /// and possibly leaving some space in accordance with the resize policy. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut set = HashSet::with_capacity(100); - /// set.insert(1); - /// set.insert(2); - /// assert!(set.capacity() >= 100); - /// set.shrink_to_fit(); - /// assert!(set.capacity() >= 2); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn shrink_to_fit(&mut self) { - self.map.shrink_to_fit() - } - - /// Shrinks the capacity of the set with a lower limit. It will drop - /// down no lower than the supplied limit while maintaining the internal rules - /// and possibly leaving some space in accordance with the resize policy. - /// - /// Panics if the current capacity is smaller than the supplied - /// minimum capacity. - /// - /// # Examples - /// - /// ``` - /// #![feature(shrink_to)] - /// use std::collections::HashSet; - /// - /// let mut set = HashSet::with_capacity(100); - /// set.insert(1); - /// set.insert(2); - /// assert!(set.capacity() >= 100); - /// set.shrink_to(10); - /// assert!(set.capacity() >= 10); - /// set.shrink_to(0); - /// assert!(set.capacity() >= 2); - /// ``` - #[inline] - #[unstable(feature = "shrink_to", reason = "new API", issue="0")] - pub fn shrink_to(&mut self, min_capacity: usize) { - self.map.shrink_to(min_capacity) - } - - /// An iterator visiting all elements in arbitrary order. - /// The iterator element type is `&'a T`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let mut set = HashSet::new(); - /// set.insert("a"); - /// set.insert("b"); - /// - /// // Will print in an arbitrary order. - /// for x in set.iter() { - /// println!("{}", x); - /// } - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn iter(&self) -> Iter<T> { - Iter { iter: self.map.keys() } - } - - /// Visits the values representing the difference, - /// i.e. the values that are in `self` but not in `other`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); - /// - /// // Can be seen as `a - b`. - /// for x in a.difference(&b) { - /// println!("{}", x); // Print 1 - /// } - /// - /// let diff: HashSet<_> = a.difference(&b).collect(); - /// assert_eq!(diff, [1].iter().collect()); - /// - /// // Note that difference is not symmetric, - /// // and `b - a` means something else: - /// let diff: HashSet<_> = b.difference(&a).collect(); - /// assert_eq!(diff, [4].iter().collect()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn difference<'a>(&'a self, other: &'a HashSet<T, S>) -> Difference<'a, T, S> { - Difference { - iter: self.iter(), - other, - } - } - - /// Visits the values representing the symmetric difference, - /// i.e. the values that are in `self` or in `other` but not in both. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); - /// - /// // Print 1, 4 in arbitrary order. - /// for x in a.symmetric_difference(&b) { - /// println!("{}", x); - /// } - /// - /// let diff1: HashSet<_> = a.symmetric_difference(&b).collect(); - /// let diff2: HashSet<_> = b.symmetric_difference(&a).collect(); - /// - /// assert_eq!(diff1, diff2); - /// assert_eq!(diff1, [1, 4].iter().collect()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn symmetric_difference<'a>(&'a self, - other: &'a HashSet<T, S>) - -> SymmetricDifference<'a, T, S> { - SymmetricDifference { iter: self.difference(other).chain(other.difference(self)) } - } - - /// Visits the values representing the intersection, - /// i.e. the values that are both in `self` and `other`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); - /// - /// // Print 2, 3 in arbitrary order. - /// for x in a.intersection(&b) { - /// println!("{}", x); - /// } - /// - /// let intersection: HashSet<_> = a.intersection(&b).collect(); - /// assert_eq!(intersection, [2, 3].iter().collect()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn intersection<'a>(&'a self, other: &'a HashSet<T, S>) -> Intersection<'a, T, S> { - Intersection { - iter: self.iter(), - other, - } - } - - /// Visits the values representing the union, - /// i.e. all the values in `self` or `other`, without duplicates. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let b: HashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); - /// - /// // Print 1, 2, 3, 4 in arbitrary order. - /// for x in a.union(&b) { - /// println!("{}", x); - /// } - /// - /// let union: HashSet<_> = a.union(&b).collect(); - /// assert_eq!(union, [1, 2, 3, 4].iter().collect()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S> { - Union { iter: self.iter().chain(other.difference(self)) } - } - - /// Returns the number of elements in the set. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut v = HashSet::new(); - /// assert_eq!(v.len(), 0); - /// v.insert(1); - /// assert_eq!(v.len(), 1); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn len(&self) -> usize { - self.map.len() - } - - /// Returns true if the set contains no elements. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut v = HashSet::new(); - /// assert!(v.is_empty()); - /// v.insert(1); - /// assert!(!v.is_empty()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_empty(&self) -> bool { - self.map.is_empty() - } - - /// Clears the set, returning all elements in an iterator. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// assert!(!set.is_empty()); - /// - /// // print 1, 2, 3 in an arbitrary order - /// for i in set.drain() { - /// println!("{}", i); - /// } - /// - /// assert!(set.is_empty()); - /// ``` - #[inline] - #[stable(feature = "drain", since = "1.6.0")] - pub fn drain(&mut self) -> Drain<T> { - Drain { iter: self.map.drain() } - } - - /// Clears the set, removing all values. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut v = HashSet::new(); - /// v.insert(1); - /// v.clear(); - /// assert!(v.is_empty()); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn clear(&mut self) { - self.map.clear() - } - - /// Returns `true` if the set contains a value. - /// - /// The value may be any borrowed form of the set's value type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// assert_eq!(set.contains(&1), true); - /// assert_eq!(set.contains(&4), false); - /// ``` - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - #[stable(feature = "rust1", since = "1.0.0")] - pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool - where T: Borrow<Q>, - Q: Hash + Eq - { - self.map.contains_key(value) - } - - /// Returns a reference to the value in the set, if any, that is equal to the given value. - /// - /// The value may be any borrowed form of the set's value type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// assert_eq!(set.get(&2), Some(&2)); - /// assert_eq!(set.get(&4), None); - /// ``` - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - #[stable(feature = "set_recovery", since = "1.9.0")] - pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T> - where T: Borrow<Q>, - Q: Hash + Eq - { - Recover::get(&self.map, value) - } - - /// Returns `true` if `self` has no elements in common with `other`. - /// This is equivalent to checking for an empty intersection. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let mut b = HashSet::new(); - /// - /// assert_eq!(a.is_disjoint(&b), true); - /// b.insert(4); - /// assert_eq!(a.is_disjoint(&b), true); - /// b.insert(1); - /// assert_eq!(a.is_disjoint(&b), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_disjoint(&self, other: &HashSet<T, S>) -> bool { - self.iter().all(|v| !other.contains(v)) - } - - /// Returns `true` if the set is a subset of another, - /// i.e. `other` contains at least all the values in `self`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let sup: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// let mut set = HashSet::new(); - /// - /// assert_eq!(set.is_subset(&sup), true); - /// set.insert(2); - /// assert_eq!(set.is_subset(&sup), true); - /// set.insert(4); - /// assert_eq!(set.is_subset(&sup), false); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_subset(&self, other: &HashSet<T, S>) -> bool { - self.iter().all(|v| other.contains(v)) - } - - /// Returns `true` if the set is a superset of another, - /// i.e. `self` contains at least all the values in `other`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let sub: HashSet<_> = [1, 2].iter().cloned().collect(); - /// let mut set = HashSet::new(); - /// - /// assert_eq!(set.is_superset(&sub), false); - /// - /// set.insert(0); - /// set.insert(1); - /// assert_eq!(set.is_superset(&sub), false); - /// - /// set.insert(2); - /// assert_eq!(set.is_superset(&sub), true); - /// ``` - #[inline] - #[stable(feature = "rust1", since = "1.0.0")] - pub fn is_superset(&self, other: &HashSet<T, S>) -> bool { - other.is_subset(self) - } - - /// Adds a value to the set. - /// - /// If the set did not have this value present, `true` is returned. - /// - /// If the set did have this value present, `false` is returned. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut set = HashSet::new(); - /// - /// assert_eq!(set.insert(2), true); - /// assert_eq!(set.insert(2), false); - /// assert_eq!(set.len(), 1); - /// ``` - #[stable(feature = "rust1", since = "1.0.0")] - pub fn insert(&mut self, value: T) -> bool { - self.map.insert(value, ()).is_none() - } - - /// Adds a value to the set, replacing the existing value, if any, that is equal to the given - /// one. Returns the replaced value. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut set = HashSet::new(); - /// set.insert(Vec::<i32>::new()); - /// - /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 0); - /// set.replace(Vec::with_capacity(10)); - /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 10); - /// ``` - #[stable(feature = "set_recovery", since = "1.9.0")] - pub fn replace(&mut self, value: T) -> Option<T> { - Recover::replace(&mut self.map, value) - } - - /// Removes a value from the set. Returns `true` if the value was - /// present in the set. - /// - /// The value may be any borrowed form of the set's value type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut set = HashSet::new(); - /// - /// set.insert(2); - /// assert_eq!(set.remove(&2), true); - /// assert_eq!(set.remove(&2), false); - /// ``` - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - #[stable(feature = "rust1", since = "1.0.0")] - pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool - where T: Borrow<Q>, - Q: Hash + Eq - { - self.map.remove(value).is_some() - } - - /// Removes and returns the value in the set, if any, that is equal to the given one. - /// - /// The value may be any borrowed form of the set's value type, but - /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for - /// the value type. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let mut set: HashSet<_> = [1, 2, 3].iter().cloned().collect(); - /// assert_eq!(set.take(&2), Some(2)); - /// assert_eq!(set.take(&2), None); - /// ``` - /// - /// [`Eq`]: ../../std/cmp/trait.Eq.html - /// [`Hash`]: ../../std/hash/trait.Hash.html - #[stable(feature = "set_recovery", since = "1.9.0")] - pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> - where T: Borrow<Q>, - Q: Hash + Eq - { - Recover::take(&mut self.map, value) - } - - /// Retains only the elements specified by the predicate. - /// - /// In other words, remove all elements `e` such that `f(&e)` returns `false`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let xs = [1,2,3,4,5,6]; - /// let mut set: HashSet<i32> = xs.iter().cloned().collect(); - /// set.retain(|&k| k % 2 == 0); - /// assert_eq!(set.len(), 3); - /// ``` - #[stable(feature = "retain_hash_collection", since = "1.18.0")] - pub fn retain<F>(&mut self, mut f: F) - where F: FnMut(&T) -> bool - { - self.map.retain(|k, _| f(k)); - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T, S> PartialEq for HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher -{ - fn eq(&self, other: &HashSet<T, S>) -> bool { - if self.len() != other.len() { - return false; - } - - self.iter().all(|key| other.contains(key)) - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T, S> Eq for HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher -{ -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T, S> fmt::Debug for HashSet<T, S> - where T: Eq + Hash + fmt::Debug, - S: BuildHasher -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_set().entries(self.iter()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T, S> FromIterator<T> for HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher + Default -{ - fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> HashSet<T, S> { - let mut set = HashSet::with_hasher(Default::default()); - set.extend(iter); - set - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T, S> Extend<T> for HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher -{ - fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { - self.map.extend(iter.into_iter().map(|k| (k, ()))); - } -} - -#[stable(feature = "hash_extend_copy", since = "1.4.0")] -impl<'a, T, S> Extend<&'a T> for HashSet<T, S> - where T: 'a + Eq + Hash + Copy, - S: BuildHasher -{ - fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { - self.extend(iter.into_iter().cloned()); - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T, S> Default for HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher + Default -{ - /// Creates an empty `HashSet<T, S>` with the `Default` value for the hasher. - fn default() -> HashSet<T, S> { - HashSet { map: HashMap::default() } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, 'b, T, S> BitOr<&'b HashSet<T, S>> for &'a HashSet<T, S> - where T: Eq + Hash + Clone, - S: BuildHasher + Default -{ - type Output = HashSet<T, S>; - - /// Returns the union of `self` and `rhs` as a new `HashSet<T, S>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect(); - /// - /// let set = &a | &b; - /// - /// let mut i = 0; - /// let expected = [1, 2, 3, 4, 5]; - /// for x in &set { - /// assert!(expected.contains(x)); - /// i += 1; - /// } - /// assert_eq!(i, expected.len()); - /// ``` - fn bitor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { - self.union(rhs).cloned().collect() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, 'b, T, S> BitAnd<&'b HashSet<T, S>> for &'a HashSet<T, S> - where T: Eq + Hash + Clone, - S: BuildHasher + Default -{ - type Output = HashSet<T, S>; - - /// Returns the intersection of `self` and `rhs` as a new `HashSet<T, S>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: HashSet<_> = vec![2, 3, 4].into_iter().collect(); - /// - /// let set = &a & &b; - /// - /// let mut i = 0; - /// let expected = [2, 3]; - /// for x in &set { - /// assert!(expected.contains(x)); - /// i += 1; - /// } - /// assert_eq!(i, expected.len()); - /// ``` - fn bitand(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { - self.intersection(rhs).cloned().collect() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, 'b, T, S> BitXor<&'b HashSet<T, S>> for &'a HashSet<T, S> - where T: Eq + Hash + Clone, - S: BuildHasher + Default -{ - type Output = HashSet<T, S>; - - /// Returns the symmetric difference of `self` and `rhs` as a new `HashSet<T, S>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect(); - /// - /// let set = &a ^ &b; - /// - /// let mut i = 0; - /// let expected = [1, 2, 4, 5]; - /// for x in &set { - /// assert!(expected.contains(x)); - /// i += 1; - /// } - /// assert_eq!(i, expected.len()); - /// ``` - fn bitxor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { - self.symmetric_difference(rhs).cloned().collect() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, 'b, T, S> Sub<&'b HashSet<T, S>> for &'a HashSet<T, S> - where T: Eq + Hash + Clone, - S: BuildHasher + Default -{ - type Output = HashSet<T, S>; - - /// Returns the difference of `self` and `rhs` as a new `HashSet<T, S>`. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// - /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect(); - /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect(); - /// - /// let set = &a - &b; - /// - /// let mut i = 0; - /// let expected = [1, 2]; - /// for x in &set { - /// assert!(expected.contains(x)); - /// i += 1; - /// } - /// assert_eq!(i, expected.len()); - /// ``` - fn sub(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { - self.difference(rhs).cloned().collect() - } -} - -/// An iterator over the items of a `HashSet`. -/// -/// This `struct` is created by the [`iter`] method on [`HashSet`]. -/// See its documentation for more. -/// -/// [`HashSet`]: struct.HashSet.html -/// [`iter`]: struct.HashSet.html#method.iter -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Iter<'a, K: 'a> { - iter: Keys<'a, K, ()>, -} - -/// An owning iterator over the items of a `HashSet`. -/// -/// This `struct` is created by the [`into_iter`] method on [`HashSet`][`HashSet`] -/// (provided by the `IntoIterator` trait). See its documentation for more. -/// -/// [`HashSet`]: struct.HashSet.html -/// [`into_iter`]: struct.HashSet.html#method.into_iter -#[stable(feature = "rust1", since = "1.0.0")] -pub struct IntoIter<K> { - iter: map::IntoIter<K, ()>, -} - -/// A draining iterator over the items of a `HashSet`. -/// -/// This `struct` is created by the [`drain`] method on [`HashSet`]. -/// See its documentation for more. -/// -/// [`HashSet`]: struct.HashSet.html -/// [`drain`]: struct.HashSet.html#method.drain -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Drain<'a, K: 'a> { - iter: map::Drain<'a, K, ()>, -} - -/// A lazy iterator producing elements in the intersection of `HashSet`s. -/// -/// This `struct` is created by the [`intersection`] method on [`HashSet`]. -/// See its documentation for more. -/// -/// [`HashSet`]: struct.HashSet.html -/// [`intersection`]: struct.HashSet.html#method.intersection -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Intersection<'a, T: 'a, S: 'a> { - // iterator of the first set - iter: Iter<'a, T>, - // the second set - other: &'a HashSet<T, S>, -} - -/// A lazy iterator producing elements in the difference of `HashSet`s. -/// -/// This `struct` is created by the [`difference`] method on [`HashSet`]. -/// See its documentation for more. -/// -/// [`HashSet`]: struct.HashSet.html -/// [`difference`]: struct.HashSet.html#method.difference -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Difference<'a, T: 'a, S: 'a> { - // iterator of the first set - iter: Iter<'a, T>, - // the second set - other: &'a HashSet<T, S>, -} - -/// A lazy iterator producing elements in the symmetric difference of `HashSet`s. -/// -/// This `struct` is created by the [`symmetric_difference`] method on -/// [`HashSet`]. See its documentation for more. -/// -/// [`HashSet`]: struct.HashSet.html -/// [`symmetric_difference`]: struct.HashSet.html#method.symmetric_difference -#[stable(feature = "rust1", since = "1.0.0")] -pub struct SymmetricDifference<'a, T: 'a, S: 'a> { - iter: Chain<Difference<'a, T, S>, Difference<'a, T, S>>, -} - -/// A lazy iterator producing elements in the union of `HashSet`s. -/// -/// This `struct` is created by the [`union`] method on [`HashSet`]. -/// See its documentation for more. -/// -/// [`HashSet`]: struct.HashSet.html -/// [`union`]: struct.HashSet.html#method.union -#[stable(feature = "rust1", since = "1.0.0")] -pub struct Union<'a, T: 'a, S: 'a> { - iter: Chain<Iter<'a, T>, Difference<'a, T, S>>, -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> IntoIterator for &'a HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher -{ - type Item = &'a T; - type IntoIter = Iter<'a, T>; - - fn into_iter(self) -> Iter<'a, T> { - self.iter() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<T, S> IntoIterator for HashSet<T, S> - where T: Eq + Hash, - S: BuildHasher -{ - type Item = T; - type IntoIter = IntoIter<T>; - - /// Creates a consuming iterator, that is, one that moves each value out - /// of the set in arbitrary order. The set cannot be used after calling - /// this. - /// - /// # Examples - /// - /// ``` - /// use std::collections::HashSet; - /// let mut set = HashSet::new(); - /// set.insert("a".to_string()); - /// set.insert("b".to_string()); - /// - /// // Not possible to collect to a Vec<String> with a regular `.iter()`. - /// let v: Vec<String> = set.into_iter().collect(); - /// - /// // Will print in an arbitrary order. - /// for x in &v { - /// println!("{}", x); - /// } - /// ``` - fn into_iter(self) -> IntoIter<T> { - IntoIter { iter: self.map.into_iter() } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K> Clone for Iter<'a, K> { - fn clone(&self) -> Iter<'a, K> { - Iter { iter: self.iter.clone() } - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K> Iterator for Iter<'a, K> { - type Item = &'a K; - - fn next(&mut self) -> Option<&'a K> { - self.iter.next() - } - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K> ExactSizeIterator for Iter<'a, K> { - fn len(&self) -> usize { - self.iter.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K> FusedIterator for Iter<'a, K> {} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K: fmt::Debug> fmt::Debug for Iter<'a, K> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<K> Iterator for IntoIter<K> { - type Item = K; - - fn next(&mut self) -> Option<K> { - self.iter.next().map(|(k, _)| k) - } - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<K> ExactSizeIterator for IntoIter<K> { - fn len(&self) -> usize { - self.iter.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<K> FusedIterator for IntoIter<K> {} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<K: fmt::Debug> fmt::Debug for IntoIter<K> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - let entries_iter = self.iter - .inner - .iter() - .map(|(k, _)| k); - f.debug_list().entries(entries_iter).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K> Iterator for Drain<'a, K> { - type Item = K; - - fn next(&mut self) -> Option<K> { - self.iter.next().map(|(k, _)| k) - } - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, K> ExactSizeIterator for Drain<'a, K> { - fn len(&self) -> usize { - self.iter.len() - } -} -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, K> FusedIterator for Drain<'a, K> {} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, K: fmt::Debug> fmt::Debug for Drain<'a, K> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - let entries_iter = self.iter - .inner - .iter() - .map(|(k, _)| k); - f.debug_list().entries(entries_iter).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Clone for Intersection<'a, T, S> { - fn clone(&self) -> Intersection<'a, T, S> { - Intersection { iter: self.iter.clone(), ..*self } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Iterator for Intersection<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - loop { - let elt = self.iter.next()?; - if self.other.contains(elt) { - return Some(elt); - } - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - let (_, upper) = self.iter.size_hint(); - (0, upper) - } -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, T, S> fmt::Debug for Intersection<'a, T, S> - where T: fmt::Debug + Eq + Hash, - S: BuildHasher -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, T, S> FusedIterator for Intersection<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Clone for Difference<'a, T, S> { - fn clone(&self) -> Difference<'a, T, S> { - Difference { iter: self.iter.clone(), ..*self } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Iterator for Difference<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - loop { - let elt = self.iter.next()?; - if !self.other.contains(elt) { - return Some(elt); - } - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - let (_, upper) = self.iter.size_hint(); - (0, upper) - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, T, S> FusedIterator for Difference<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, T, S> fmt::Debug for Difference<'a, T, S> - where T: fmt::Debug + Eq + Hash, - S: BuildHasher -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Clone for SymmetricDifference<'a, T, S> { - fn clone(&self) -> SymmetricDifference<'a, T, S> { - SymmetricDifference { iter: self.iter.clone() } - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - self.iter.next() - } - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, T, S> FusedIterator for SymmetricDifference<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, T, S> fmt::Debug for SymmetricDifference<'a, T, S> - where T: fmt::Debug + Eq + Hash, - S: BuildHasher -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Clone for Union<'a, T, S> { - fn clone(&self) -> Union<'a, T, S> { - Union { iter: self.iter.clone() } - } -} - -#[stable(feature = "fused", since = "1.26.0")] -impl<'a, T, S> FusedIterator for Union<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ -} - -#[stable(feature = "std_debug", since = "1.16.0")] -impl<'a, T, S> fmt::Debug for Union<'a, T, S> - where T: fmt::Debug + Eq + Hash, - S: BuildHasher -{ - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - f.debug_list().entries(self.clone()).finish() - } -} - -#[stable(feature = "rust1", since = "1.0.0")] -impl<'a, T, S> Iterator for Union<'a, T, S> - where T: Eq + Hash, - S: BuildHasher -{ - type Item = &'a T; - - fn next(&mut self) -> Option<&'a T> { - self.iter.next() - } - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} - -#[allow(dead_code)] -fn assert_covariance() { - fn set<'new>(v: HashSet<&'static str>) -> HashSet<&'new str> { - v - } - fn iter<'a, 'new>(v: Iter<'a, &'static str>) -> Iter<'a, &'new str> { - v - } - fn into_iter<'new>(v: IntoIter<&'static str>) -> IntoIter<&'new str> { - v - } - fn difference<'a, 'new>(v: Difference<'a, &'static str, RandomState>) - -> Difference<'a, &'new str, RandomState> { - v - } - fn symmetric_difference<'a, 'new>(v: SymmetricDifference<'a, &'static str, RandomState>) - -> SymmetricDifference<'a, &'new str, RandomState> { - v - } - fn intersection<'a, 'new>(v: Intersection<'a, &'static str, RandomState>) - -> Intersection<'a, &'new str, RandomState> { - v - } - fn union<'a, 'new>(v: Union<'a, &'static str, RandomState>) - -> Union<'a, &'new str, RandomState> { - v - } - fn drain<'new>(d: Drain<'static, &'static str>) -> Drain<'new, &'new str> { - d - } -} - -#[cfg(test)] -mod test_set { - use super::HashSet; - use super::super::map::RandomState; - - #[test] - fn test_zero_capacities() { - type HS = HashSet<i32>; - - let s = HS::new(); - assert_eq!(s.capacity(), 0); - - let s = HS::default(); - assert_eq!(s.capacity(), 0); - - let s = HS::with_hasher(RandomState::new()); - assert_eq!(s.capacity(), 0); - - let s = HS::with_capacity(0); - assert_eq!(s.capacity(), 0); - - let s = HS::with_capacity_and_hasher(0, RandomState::new()); - assert_eq!(s.capacity(), 0); - - let mut s = HS::new(); - s.insert(1); - s.insert(2); - s.remove(&1); - s.remove(&2); - s.shrink_to_fit(); - assert_eq!(s.capacity(), 0); - - let mut s = HS::new(); - s.reserve(0); - assert_eq!(s.capacity(), 0); - } - - #[test] - fn test_disjoint() { - let mut xs = HashSet::new(); - let mut ys = HashSet::new(); - assert!(xs.is_disjoint(&ys)); - assert!(ys.is_disjoint(&xs)); - assert!(xs.insert(5)); - assert!(ys.insert(11)); - assert!(xs.is_disjoint(&ys)); - assert!(ys.is_disjoint(&xs)); - assert!(xs.insert(7)); - assert!(xs.insert(19)); - assert!(xs.insert(4)); - assert!(ys.insert(2)); - assert!(ys.insert(-11)); - assert!(xs.is_disjoint(&ys)); - assert!(ys.is_disjoint(&xs)); - assert!(ys.insert(7)); - assert!(!xs.is_disjoint(&ys)); - assert!(!ys.is_disjoint(&xs)); - } - - #[test] - fn test_subset_and_superset() { - let mut a = HashSet::new(); - assert!(a.insert(0)); - assert!(a.insert(5)); - assert!(a.insert(11)); - assert!(a.insert(7)); - - let mut b = HashSet::new(); - assert!(b.insert(0)); - assert!(b.insert(7)); - assert!(b.insert(19)); - assert!(b.insert(250)); - assert!(b.insert(11)); - assert!(b.insert(200)); - - assert!(!a.is_subset(&b)); - assert!(!a.is_superset(&b)); - assert!(!b.is_subset(&a)); - assert!(!b.is_superset(&a)); - - assert!(b.insert(5)); - - assert!(a.is_subset(&b)); - assert!(!a.is_superset(&b)); - assert!(!b.is_subset(&a)); - assert!(b.is_superset(&a)); - } - - #[test] - fn test_iterate() { - let mut a = HashSet::new(); - for i in 0..32 { - assert!(a.insert(i)); - } - let mut observed: u32 = 0; - for k in &a { - observed |= 1 << *k; - } - assert_eq!(observed, 0xFFFF_FFFF); - } - - #[test] - fn test_intersection() { - let mut a = HashSet::new(); - let mut b = HashSet::new(); - - assert!(a.insert(11)); - assert!(a.insert(1)); - assert!(a.insert(3)); - assert!(a.insert(77)); - assert!(a.insert(103)); - assert!(a.insert(5)); - assert!(a.insert(-5)); - - assert!(b.insert(2)); - assert!(b.insert(11)); - assert!(b.insert(77)); - assert!(b.insert(-9)); - assert!(b.insert(-42)); - assert!(b.insert(5)); - assert!(b.insert(3)); - - let mut i = 0; - let expected = [3, 5, 11, 77]; - for x in a.intersection(&b) { - assert!(expected.contains(x)); - i += 1 - } - assert_eq!(i, expected.len()); - } - - #[test] - fn test_difference() { - let mut a = HashSet::new(); - let mut b = HashSet::new(); - - assert!(a.insert(1)); - assert!(a.insert(3)); - assert!(a.insert(5)); - assert!(a.insert(9)); - assert!(a.insert(11)); - - assert!(b.insert(3)); - assert!(b.insert(9)); - - let mut i = 0; - let expected = [1, 5, 11]; - for x in a.difference(&b) { - assert!(expected.contains(x)); - i += 1 - } - assert_eq!(i, expected.len()); - } - - #[test] - fn test_symmetric_difference() { - let mut a = HashSet::new(); - let mut b = HashSet::new(); - - assert!(a.insert(1)); - assert!(a.insert(3)); - assert!(a.insert(5)); - assert!(a.insert(9)); - assert!(a.insert(11)); - - assert!(b.insert(-2)); - assert!(b.insert(3)); - assert!(b.insert(9)); - assert!(b.insert(14)); - assert!(b.insert(22)); - - let mut i = 0; - let expected = [-2, 1, 5, 11, 14, 22]; - for x in a.symmetric_difference(&b) { - assert!(expected.contains(x)); - i += 1 - } - assert_eq!(i, expected.len()); - } - - #[test] - fn test_union() { - let mut a = HashSet::new(); - let mut b = HashSet::new(); - - assert!(a.insert(1)); - assert!(a.insert(3)); - assert!(a.insert(5)); - assert!(a.insert(9)); - assert!(a.insert(11)); - assert!(a.insert(16)); - assert!(a.insert(19)); - assert!(a.insert(24)); - - assert!(b.insert(-2)); - assert!(b.insert(1)); - assert!(b.insert(5)); - assert!(b.insert(9)); - assert!(b.insert(13)); - assert!(b.insert(19)); - - let mut i = 0; - let expected = [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24]; - for x in a.union(&b) { - assert!(expected.contains(x)); - i += 1 - } - assert_eq!(i, expected.len()); - } - - #[test] - fn test_from_iter() { - let xs = [1, 2, 3, 4, 5, 6, 7, 8, 9]; - - let set: HashSet<_> = xs.iter().cloned().collect(); - - for x in &xs { - assert!(set.contains(x)); - } - } - - #[test] - fn test_move_iter() { - let hs = { - let mut hs = HashSet::new(); - - hs.insert('a'); - hs.insert('b'); - - hs - }; - - let v = hs.into_iter().collect::<Vec<char>>(); - assert!(v == ['a', 'b'] || v == ['b', 'a']); - } - - #[test] - fn test_eq() { - // These constants once happened to expose a bug in insert(). - // I'm keeping them around to prevent a regression. - let mut s1 = HashSet::new(); - - s1.insert(1); - s1.insert(2); - s1.insert(3); - - let mut s2 = HashSet::new(); - - s2.insert(1); - s2.insert(2); - - assert!(s1 != s2); - - s2.insert(3); - - assert_eq!(s1, s2); - } - - #[test] - fn test_show() { - let mut set = HashSet::new(); - let empty = HashSet::<i32>::new(); - - set.insert(1); - set.insert(2); - - let set_str = format!("{:?}", set); - - assert!(set_str == "{1, 2}" || set_str == "{2, 1}"); - assert_eq!(format!("{:?}", empty), "{}"); - } - - #[test] - fn test_trivial_drain() { - let mut s = HashSet::<i32>::new(); - for _ in s.drain() {} - assert!(s.is_empty()); - drop(s); - - let mut s = HashSet::<i32>::new(); - drop(s.drain()); - assert!(s.is_empty()); - } - - #[test] - fn test_drain() { - let mut s: HashSet<_> = (1..100).collect(); - - // try this a bunch of times to make sure we don't screw up internal state. - for _ in 0..20 { - assert_eq!(s.len(), 99); - - { - let mut last_i = 0; - let mut d = s.drain(); - for (i, x) in d.by_ref().take(50).enumerate() { - last_i = i; - assert!(x != 0); - } - assert_eq!(last_i, 49); - } - - for _ in &s { - panic!("s should be empty!"); - } - - // reset to try again. - s.extend(1..100); - } - } - - #[test] - fn test_replace() { - use hash; - - #[derive(Debug)] - struct Foo(&'static str, i32); - - impl PartialEq for Foo { - fn eq(&self, other: &Self) -> bool { - self.0 == other.0 - } - } - - impl Eq for Foo {} - - impl hash::Hash for Foo { - fn hash<H: hash::Hasher>(&self, h: &mut H) { - self.0.hash(h); - } - } - - let mut s = HashSet::new(); - assert_eq!(s.replace(Foo("a", 1)), None); - assert_eq!(s.len(), 1); - assert_eq!(s.replace(Foo("a", 2)), Some(Foo("a", 1))); - assert_eq!(s.len(), 1); - - let mut it = s.iter(); - assert_eq!(it.next(), Some(&Foo("a", 2))); - assert_eq!(it.next(), None); - } - - #[test] - fn test_extend_ref() { - let mut a = HashSet::new(); - a.insert(1); - - a.extend(&[2, 3, 4]); - - assert_eq!(a.len(), 4); - assert!(a.contains(&1)); - assert!(a.contains(&2)); - assert!(a.contains(&3)); - assert!(a.contains(&4)); - - let mut b = HashSet::new(); - b.insert(5); - b.insert(6); - - a.extend(&b); - - assert_eq!(a.len(), 6); - assert!(a.contains(&1)); - assert!(a.contains(&2)); - assert!(a.contains(&3)); - assert!(a.contains(&4)); - assert!(a.contains(&5)); - assert!(a.contains(&6)); - } - - #[test] - fn test_retain() { - let xs = [1, 2, 3, 4, 5, 6]; - let mut set: HashSet<i32> = xs.iter().cloned().collect(); - set.retain(|&k| k % 2 == 0); - assert_eq!(set.len(), 3); - assert!(set.contains(&2)); - assert!(set.contains(&4)); - assert!(set.contains(&6)); - } -} diff --git a/ctr-std/src/collections/hash/table.rs b/ctr-std/src/collections/hash/table.rs deleted file mode 100644 index 2b31918..0000000 --- a/ctr-std/src/collections/hash/table.rs +++ /dev/null @@ -1,1133 +0,0 @@ -// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -use alloc::{Global, Alloc, Layout, LayoutErr, handle_alloc_error}; -use collections::CollectionAllocErr; -use hash::{BuildHasher, Hash, Hasher}; -use marker; -use mem::{size_of, needs_drop}; -use mem; -use ops::{Deref, DerefMut}; -use ptr::{self, Unique, NonNull}; -use hint; - -use self::BucketState::*; - -/// Integer type used for stored hash values. -/// -/// No more than bit_width(usize) bits are needed to select a bucket. -/// -/// The most significant bit is ours to use for tagging `SafeHash`. -/// -/// (Even if we could have usize::MAX bytes allocated for buckets, -/// each bucket stores at least a `HashUint`, so there can be no more than -/// usize::MAX / size_of(usize) buckets.) -type HashUint = usize; - -const EMPTY_BUCKET: HashUint = 0; -const EMPTY: usize = 1; - -/// Special `Unique<HashUint>` that uses the lower bit of the pointer -/// to expose a boolean tag. -/// Note: when the pointer is initialized to EMPTY `.ptr()` will return -/// null and the tag functions shouldn't be used. -struct TaggedHashUintPtr(Unique<HashUint>); - -impl TaggedHashUintPtr { - #[inline] - unsafe fn new(ptr: *mut HashUint) -> Self { - debug_assert!(ptr as usize & 1 == 0 || ptr as usize == EMPTY as usize); - TaggedHashUintPtr(Unique::new_unchecked(ptr)) - } - - #[inline] - fn set_tag(&mut self, value: bool) { - let mut usize_ptr = self.0.as_ptr() as usize; - unsafe { - if value { - usize_ptr |= 1; - } else { - usize_ptr &= !1; - } - self.0 = Unique::new_unchecked(usize_ptr as *mut HashUint) - } - } - - #[inline] - fn tag(&self) -> bool { - (self.0.as_ptr() as usize) & 1 == 1 - } - - #[inline] - fn ptr(&self) -> *mut HashUint { - (self.0.as_ptr() as usize & !1) as *mut HashUint - } -} - -/// The raw hashtable, providing safe-ish access to the unzipped and highly -/// optimized arrays of hashes, and key-value pairs. -/// -/// This design is a lot faster than the naive -/// `Vec<Option<(u64, K, V)>>`, because we don't pay for the overhead of an -/// option on every element, and we get a generally more cache-aware design. -/// -/// Essential invariants of this structure: -/// -/// - if `t.hashes[i] == EMPTY_BUCKET`, then `Bucket::at_index(&t, i).raw` -/// points to 'undefined' contents. Don't read from it. This invariant is -/// enforced outside this module with the `EmptyBucket`, `FullBucket`, -/// and `SafeHash` types. -/// -/// - An `EmptyBucket` is only constructed at an index with -/// a hash of EMPTY_BUCKET. -/// -/// - A `FullBucket` is only constructed at an index with a -/// non-EMPTY_BUCKET hash. -/// -/// - A `SafeHash` is only constructed for non-`EMPTY_BUCKET` hash. We get -/// around hashes of zero by changing them to 0x8000_0000_0000_0000, -/// which will likely map to the same bucket, while not being confused -/// with "empty". -/// -/// - Both "arrays represented by pointers" are the same length: -/// `capacity`. This is set at creation and never changes. The arrays -/// are unzipped and are more cache aware (scanning through 8 hashes -/// brings in at most 2 cache lines, since they're all right beside each -/// other). This layout may waste space in padding such as in a map from -/// u64 to u8, but is a more cache conscious layout as the key-value pairs -/// are only very shortly probed and the desired value will be in the same -/// or next cache line. -/// -/// You can kind of think of this module/data structure as a safe wrapper -/// around just the "table" part of the hashtable. It enforces some -/// invariants at the type level and employs some performance trickery, -/// but in general is just a tricked out `Vec<Option<(u64, K, V)>>`. -/// -/// The hashtable also exposes a special boolean tag. The tag defaults to false -/// when the RawTable is created and is accessible with the `tag` and `set_tag` -/// functions. -pub struct RawTable<K, V> { - capacity_mask: usize, - size: usize, - hashes: TaggedHashUintPtr, - - // Because K/V do not appear directly in any of the types in the struct, - // inform rustc that in fact instances of K and V are reachable from here. - marker: marker::PhantomData<(K, V)>, -} - -// An unsafe view of a RawTable bucket -// Valid indexes are within [0..table_capacity) -pub struct RawBucket<K, V> { - hash_start: *mut HashUint, - // We use *const to ensure covariance with respect to K and V - pair_start: *const (K, V), - idx: usize, - _marker: marker::PhantomData<(K, V)>, -} - -impl<K, V> Copy for RawBucket<K, V> {} -impl<K, V> Clone for RawBucket<K, V> { - fn clone(&self) -> RawBucket<K, V> { - *self - } -} - -pub struct Bucket<K, V, M> { - raw: RawBucket<K, V>, - table: M, -} - -impl<K, V, M: Copy> Copy for Bucket<K, V, M> {} -impl<K, V, M: Copy> Clone for Bucket<K, V, M> { - fn clone(&self) -> Bucket<K, V, M> { - *self - } -} - -pub struct EmptyBucket<K, V, M> { - raw: RawBucket<K, V>, - table: M, -} - -pub struct FullBucket<K, V, M> { - raw: RawBucket<K, V>, - table: M, -} - -pub type FullBucketMut<'table, K, V> = FullBucket<K, V, &'table mut RawTable<K, V>>; - -pub enum BucketState<K, V, M> { - Empty(EmptyBucket<K, V, M>), - Full(FullBucket<K, V, M>), -} - -// A GapThenFull encapsulates the state of two consecutive buckets at once. -// The first bucket, called the gap, is known to be empty. -// The second bucket is full. -pub struct GapThenFull<K, V, M> { - gap: EmptyBucket<K, V, ()>, - full: FullBucket<K, V, M>, -} - -/// A hash that is not zero, since we use a hash of zero to represent empty -/// buckets. -#[derive(PartialEq, Copy, Clone)] -pub struct SafeHash { - hash: HashUint, -} - -impl SafeHash { - /// Peek at the hash value, which is guaranteed to be non-zero. - #[inline(always)] - pub fn inspect(&self) -> HashUint { - self.hash - } - - #[inline(always)] - pub fn new(hash: u64) -> Self { - // We need to avoid 0 in order to prevent collisions with - // EMPTY_HASH. We can maintain our precious uniform distribution - // of initial indexes by unconditionally setting the MSB, - // effectively reducing the hashes by one bit. - // - // Truncate hash to fit in `HashUint`. - let hash_bits = size_of::<HashUint>() * 8; - SafeHash { hash: (1 << (hash_bits - 1)) | (hash as HashUint) } - } -} - -/// We need to remove hashes of 0. That's reserved for empty buckets. -/// This function wraps up `hash_keyed` to be the only way outside this -/// module to generate a SafeHash. -pub fn make_hash<T: ?Sized, S>(hash_state: &S, t: &T) -> SafeHash - where T: Hash, - S: BuildHasher -{ - let mut state = hash_state.build_hasher(); - t.hash(&mut state); - SafeHash::new(state.finish()) -} - -// `replace` casts a `*HashUint` to a `*SafeHash`. Since we statically -// ensure that a `FullBucket` points to an index with a non-zero hash, -// and a `SafeHash` is just a `HashUint` with a different name, this is -// safe. -// -// This test ensures that a `SafeHash` really IS the same size as a -// `HashUint`. If you need to change the size of `SafeHash` (and -// consequently made this test fail), `replace` needs to be -// modified to no longer assume this. -#[test] -fn can_alias_safehash_as_hash() { - assert_eq!(size_of::<SafeHash>(), size_of::<HashUint>()) -} - -// RawBucket methods are unsafe as it's possible to -// make a RawBucket point to invalid memory using safe code. -impl<K, V> RawBucket<K, V> { - unsafe fn hash(&self) -> *mut HashUint { - self.hash_start.offset(self.idx as isize) - } - unsafe fn pair(&self) -> *mut (K, V) { - self.pair_start.offset(self.idx as isize) as *mut (K, V) - } - unsafe fn hash_pair(&self) -> (*mut HashUint, *mut (K, V)) { - (self.hash(), self.pair()) - } -} - -// Buckets hold references to the table. -impl<K, V, M> FullBucket<K, V, M> { - /// Borrow a reference to the table. - pub fn table(&self) -> &M { - &self.table - } - /// Borrow a mutable reference to the table. - pub fn table_mut(&mut self) -> &mut M { - &mut self.table - } - /// Move out the reference to the table. - pub fn into_table(self) -> M { - self.table - } - /// Get the raw index. - pub fn index(&self) -> usize { - self.raw.idx - } - /// Get the raw bucket. - pub fn raw(&self) -> RawBucket<K, V> { - self.raw - } -} - -impl<K, V, M> EmptyBucket<K, V, M> { - /// Borrow a reference to the table. - pub fn table(&self) -> &M { - &self.table - } - /// Borrow a mutable reference to the table. - pub fn table_mut(&mut self) -> &mut M { - &mut self.table - } -} - -impl<K, V, M> Bucket<K, V, M> { - /// Get the raw index. - pub fn index(&self) -> usize { - self.raw.idx - } - /// get the table. - pub fn into_table(self) -> M { - self.table - } -} - -impl<K, V, M> Deref for FullBucket<K, V, M> - where M: Deref<Target = RawTable<K, V>> -{ - type Target = RawTable<K, V>; - fn deref(&self) -> &RawTable<K, V> { - &self.table - } -} - -/// `Put` is implemented for types which provide access to a table and cannot be invalidated -/// by filling a bucket. A similar implementation for `Take` is possible. -pub trait Put<K, V> { - unsafe fn borrow_table_mut(&mut self) -> &mut RawTable<K, V>; -} - - -impl<'t, K, V> Put<K, V> for &'t mut RawTable<K, V> { - unsafe fn borrow_table_mut(&mut self) -> &mut RawTable<K, V> { - *self - } -} - -impl<K, V, M> Put<K, V> for Bucket<K, V, M> - where M: Put<K, V> -{ - unsafe fn borrow_table_mut(&mut self) -> &mut RawTable<K, V> { - self.table.borrow_table_mut() - } -} - -impl<K, V, M> Put<K, V> for FullBucket<K, V, M> - where M: Put<K, V> -{ - unsafe fn borrow_table_mut(&mut self) -> &mut RawTable<K, V> { - self.table.borrow_table_mut() - } -} - -impl<K, V, M: Deref<Target = RawTable<K, V>>> Bucket<K, V, M> { - pub fn new(table: M, hash: SafeHash) -> Bucket<K, V, M> { - Bucket::at_index(table, hash.inspect() as usize) - } - - pub fn new_from(r: RawBucket<K, V>, t: M) - -> Bucket<K, V, M> - { - Bucket { - raw: r, - table: t, - } - } - - pub fn at_index(table: M, ib_index: usize) -> Bucket<K, V, M> { - // if capacity is 0, then the RawBucket will be populated with bogus pointers. - // This is an uncommon case though, so avoid it in release builds. - debug_assert!(table.capacity() > 0, - "Table should have capacity at this point"); - let ib_index = ib_index & table.capacity_mask; - Bucket { - raw: table.raw_bucket_at(ib_index), - table, - } - } - - pub fn first(table: M) -> Bucket<K, V, M> { - Bucket { - raw: table.raw_bucket_at(0), - table, - } - } - - // "So a few of the first shall be last: for many be called, - // but few chosen." - // - // We'll most likely encounter a few buckets at the beginning that - // have their initial buckets near the end of the table. They were - // placed at the beginning as the probe wrapped around the table - // during insertion. We must skip forward to a bucket that won't - // get reinserted too early and won't unfairly steal others spot. - // This eliminates the need for robin hood. - pub fn head_bucket(table: M) -> Bucket<K, V, M> { - let mut bucket = Bucket::first(table); - - loop { - bucket = match bucket.peek() { - Full(full) => { - if full.displacement() == 0 { - // This bucket occupies its ideal spot. - // It indicates the start of another "cluster". - bucket = full.into_bucket(); - break; - } - // Leaving this bucket in the last cluster for later. - full.into_bucket() - } - Empty(b) => { - // Encountered a hole between clusters. - b.into_bucket() - } - }; - bucket.next(); - } - bucket - } - - /// Reads a bucket at a given index, returning an enum indicating whether - /// it's initialized or not. You need to match on this enum to get - /// the appropriate types to call most of the other functions in - /// this module. - pub fn peek(self) -> BucketState<K, V, M> { - match unsafe { *self.raw.hash() } { - EMPTY_BUCKET => { - Empty(EmptyBucket { - raw: self.raw, - table: self.table, - }) - } - _ => { - Full(FullBucket { - raw: self.raw, - table: self.table, - }) - } - } - } - - /// Modifies the bucket in place to make it point to the next slot. - pub fn next(&mut self) { - self.raw.idx = self.raw.idx.wrapping_add(1) & self.table.capacity_mask; - } - - /// Modifies the bucket in place to make it point to the previous slot. - pub fn prev(&mut self) { - self.raw.idx = self.raw.idx.wrapping_sub(1) & self.table.capacity_mask; - } -} - -impl<K, V, M: Deref<Target = RawTable<K, V>>> EmptyBucket<K, V, M> { - #[inline] - pub fn next(self) -> Bucket<K, V, M> { - let mut bucket = self.into_bucket(); - bucket.next(); - bucket - } - - #[inline] - pub fn into_bucket(self) -> Bucket<K, V, M> { - Bucket { - raw: self.raw, - table: self.table, - } - } - - pub fn gap_peek(self) -> Result<GapThenFull<K, V, M>, Bucket<K, V, M>> { - let gap = EmptyBucket { - raw: self.raw, - table: (), - }; - - match self.next().peek() { - Full(bucket) => { - Ok(GapThenFull { - gap, - full: bucket, - }) - } - Empty(e) => Err(e.into_bucket()), - } - } -} - -impl<K, V, M> EmptyBucket<K, V, M> - where M: Put<K, V> -{ - /// Puts given key and value pair, along with the key's hash, - /// into this bucket in the hashtable. Note how `self` is 'moved' into - /// this function, because this slot will no longer be empty when - /// we return! A `FullBucket` is returned for later use, pointing to - /// the newly-filled slot in the hashtable. - /// - /// Use `make_hash` to construct a `SafeHash` to pass to this function. - pub fn put(mut self, hash: SafeHash, key: K, value: V) -> FullBucket<K, V, M> { - unsafe { - *self.raw.hash() = hash.inspect(); - ptr::write(self.raw.pair(), (key, value)); - - self.table.borrow_table_mut().size += 1; - } - - FullBucket { - raw: self.raw, - table: self.table, - } - } -} - -impl<K, V, M: Deref<Target = RawTable<K, V>>> FullBucket<K, V, M> { - #[inline] - pub fn next(self) -> Bucket<K, V, M> { - let mut bucket = self.into_bucket(); - bucket.next(); - bucket - } - - #[inline] - pub fn into_bucket(self) -> Bucket<K, V, M> { - Bucket { - raw: self.raw, - table: self.table, - } - } - - /// Duplicates the current position. This can be useful for operations - /// on two or more buckets. - pub fn stash(self) -> FullBucket<K, V, Self> { - FullBucket { - raw: self.raw, - table: self, - } - } - - /// Get the distance between this bucket and the 'ideal' location - /// as determined by the key's hash stored in it. - /// - /// In the cited blog posts above, this is called the "distance to - /// initial bucket", or DIB. Also known as "probe count". - pub fn displacement(&self) -> usize { - // Calculates the distance one has to travel when going from - // `hash mod capacity` onwards to `idx mod capacity`, wrapping around - // if the destination is not reached before the end of the table. - (self.raw.idx.wrapping_sub(self.hash().inspect() as usize)) & self.table.capacity_mask - } - - #[inline] - pub fn hash(&self) -> SafeHash { - unsafe { SafeHash { hash: *self.raw.hash() } } - } - - /// Gets references to the key and value at a given index. - pub fn read(&self) -> (&K, &V) { - unsafe { - let pair_ptr = self.raw.pair(); - (&(*pair_ptr).0, &(*pair_ptr).1) - } - } -} - -// We take a mutable reference to the table instead of accepting anything that -// implements `DerefMut` to prevent fn `take` from being called on `stash`ed -// buckets. -impl<'t, K, V> FullBucket<K, V, &'t mut RawTable<K, V>> { - /// Removes this bucket's key and value from the hashtable. - /// - /// This works similarly to `put`, building an `EmptyBucket` out of the - /// taken bucket. - pub fn take(self) -> (EmptyBucket<K, V, &'t mut RawTable<K, V>>, K, V) { - self.table.size -= 1; - - unsafe { - *self.raw.hash() = EMPTY_BUCKET; - let (k, v) = ptr::read(self.raw.pair()); - (EmptyBucket { - raw: self.raw, - table: self.table, - }, - k, - v) - } - } -} - -// This use of `Put` is misleading and restrictive, but safe and sufficient for our use cases -// where `M` is a full bucket or table reference type with mutable access to the table. -impl<K, V, M> FullBucket<K, V, M> - where M: Put<K, V> -{ - pub fn replace(&mut self, h: SafeHash, k: K, v: V) -> (SafeHash, K, V) { - unsafe { - let old_hash = ptr::replace(self.raw.hash() as *mut SafeHash, h); - let (old_key, old_val) = ptr::replace(self.raw.pair(), (k, v)); - - (old_hash, old_key, old_val) - } - } -} - -impl<K, V, M> FullBucket<K, V, M> - where M: Deref<Target = RawTable<K, V>> + DerefMut -{ - /// Gets mutable references to the key and value at a given index. - pub fn read_mut(&mut self) -> (&mut K, &mut V) { - unsafe { - let pair_ptr = self.raw.pair(); - (&mut (*pair_ptr).0, &mut (*pair_ptr).1) - } - } -} - -impl<'t, K, V, M> FullBucket<K, V, M> - where M: Deref<Target = RawTable<K, V>> + 't -{ - /// Exchange a bucket state for immutable references into the table. - /// Because the underlying reference to the table is also consumed, - /// no further changes to the structure of the table are possible; - /// in exchange for this, the returned references have a longer lifetime - /// than the references returned by `read()`. - pub fn into_refs(self) -> (&'t K, &'t V) { - unsafe { - let pair_ptr = self.raw.pair(); - (&(*pair_ptr).0, &(*pair_ptr).1) - } - } -} - -impl<'t, K, V, M> FullBucket<K, V, M> - where M: Deref<Target = RawTable<K, V>> + DerefMut + 't -{ - /// This works similarly to `into_refs`, exchanging a bucket state - /// for mutable references into the table. - pub fn into_mut_refs(self) -> (&'t mut K, &'t mut V) { - unsafe { - let pair_ptr = self.raw.pair(); - (&mut (*pair_ptr).0, &mut (*pair_ptr).1) - } - } -} - -impl<K, V, M> GapThenFull<K, V, M> - where M: Deref<Target = RawTable<K, V>> -{ - #[inline] - pub fn full(&self) -> &FullBucket<K, V, M> { - &self.full - } - - pub fn into_table(self) -> M { - self.full.into_table() - } - - pub fn shift(mut self) -> Result<GapThenFull<K, V, M>, Bucket<K, V, M>> { - unsafe { - let (gap_hash, gap_pair) = self.gap.raw.hash_pair(); - let (full_hash, full_pair) = self.full.raw.hash_pair(); - *gap_hash = mem::replace(&mut *full_hash, EMPTY_BUCKET); - ptr::copy_nonoverlapping(full_pair, gap_pair, 1); - } - - let FullBucket { raw: prev_raw, .. } = self.full; - - match self.full.next().peek() { - Full(bucket) => { - self.gap.raw = prev_raw; - - self.full = bucket; - - Ok(self) - } - Empty(b) => Err(b.into_bucket()), - } - } -} - -// Returns a Layout which describes the allocation required for a hash table, -// and the offset of the array of (key, value) pairs in the allocation. -fn calculate_layout<K, V>(capacity: usize) -> Result<(Layout, usize), LayoutErr> { - let hashes = Layout::array::<HashUint>(capacity)?; - let pairs = Layout::array::<(K, V)>(capacity)?; - hashes.extend(pairs).map(|(layout, _)| { - // LLVM seems to have trouble properly const-propagating pairs.align(), - // possibly due to the use of NonZeroUsize. This little hack allows it - // to generate optimal code. - // - // See https://github.com/rust-lang/rust/issues/51346 for more details. - ( - layout, - hashes.size() + hashes.padding_needed_for(mem::align_of::<(K, V)>()), - ) - }) -} - -pub(crate) enum Fallibility { - Fallible, - Infallible, -} - -use self::Fallibility::*; - -impl<K, V> RawTable<K, V> { - /// Does not initialize the buckets. The caller should ensure they, - /// at the very least, set every hash to EMPTY_BUCKET. - /// Returns an error if it cannot allocate or capacity overflows. - unsafe fn new_uninitialized_internal( - capacity: usize, - fallibility: Fallibility, - ) -> Result<RawTable<K, V>, CollectionAllocErr> { - if capacity == 0 { - return Ok(RawTable { - size: 0, - capacity_mask: capacity.wrapping_sub(1), - hashes: TaggedHashUintPtr::new(EMPTY as *mut HashUint), - marker: marker::PhantomData, - }); - } - - // Allocating hashmaps is a little tricky. We need to allocate two - // arrays, but since we know their sizes and alignments up front, - // we just allocate a single array, and then have the subarrays - // point into it. - let (layout, _) = calculate_layout::<K, V>(capacity)?; - let buffer = Global.alloc(layout).map_err(|e| match fallibility { - Infallible => handle_alloc_error(layout), - Fallible => e, - })?; - - Ok(RawTable { - capacity_mask: capacity.wrapping_sub(1), - size: 0, - hashes: TaggedHashUintPtr::new(buffer.cast().as_ptr()), - marker: marker::PhantomData, - }) - } - - /// Does not initialize the buckets. The caller should ensure they, - /// at the very least, set every hash to EMPTY_BUCKET. - unsafe fn new_uninitialized(capacity: usize) -> RawTable<K, V> { - match Self::new_uninitialized_internal(capacity, Infallible) { - Err(CollectionAllocErr::CapacityOverflow) => panic!("capacity overflow"), - Err(CollectionAllocErr::AllocErr) => unreachable!(), - Ok(table) => { table } - } - } - - fn raw_bucket_at(&self, index: usize) -> RawBucket<K, V> { - let (_, pairs_offset) = calculate_layout::<K, V>(self.capacity()) - .unwrap_or_else(|_| unsafe { hint::unreachable_unchecked() }); - let buffer = self.hashes.ptr() as *mut u8; - unsafe { - RawBucket { - hash_start: buffer as *mut HashUint, - pair_start: buffer.add(pairs_offset) as *const (K, V), - idx: index, - _marker: marker::PhantomData, - } - } - } - - fn new_internal( - capacity: usize, - fallibility: Fallibility, - ) -> Result<RawTable<K, V>, CollectionAllocErr> { - unsafe { - let ret = RawTable::new_uninitialized_internal(capacity, fallibility)?; - ptr::write_bytes(ret.hashes.ptr(), 0, capacity); - Ok(ret) - } - } - - /// Tries to create a new raw table from a given capacity. If it cannot allocate, - /// it returns with AllocErr. - pub fn try_new(capacity: usize) -> Result<RawTable<K, V>, CollectionAllocErr> { - Self::new_internal(capacity, Fallible) - } - - /// Creates a new raw table from a given capacity. All buckets are - /// initially empty. - pub fn new(capacity: usize) -> RawTable<K, V> { - match Self::new_internal(capacity, Infallible) { - Err(CollectionAllocErr::CapacityOverflow) => panic!("capacity overflow"), - Err(CollectionAllocErr::AllocErr) => unreachable!(), - Ok(table) => { table } - } - } - - /// The hashtable's capacity, similar to a vector's. - pub fn capacity(&self) -> usize { - self.capacity_mask.wrapping_add(1) - } - - /// The number of elements ever `put` in the hashtable, minus the number - /// of elements ever `take`n. - pub fn size(&self) -> usize { - self.size - } - - fn raw_buckets(&self) -> RawBuckets<K, V> { - RawBuckets { - raw: self.raw_bucket_at(0), - elems_left: self.size, - marker: marker::PhantomData, - } - } - - pub fn iter(&self) -> Iter<K, V> { - Iter { - iter: self.raw_buckets(), - } - } - - pub fn iter_mut(&mut self) -> IterMut<K, V> { - IterMut { - iter: self.raw_buckets(), - _marker: marker::PhantomData, - } - } - - pub fn into_iter(self) -> IntoIter<K, V> { - let RawBuckets { raw, elems_left, .. } = self.raw_buckets(); - // Replace the marker regardless of lifetime bounds on parameters. - IntoIter { - iter: RawBuckets { - raw, - elems_left, - marker: marker::PhantomData, - }, - table: self, - } - } - - pub fn drain(&mut self) -> Drain<K, V> { - let RawBuckets { raw, elems_left, .. } = self.raw_buckets(); - // Replace the marker regardless of lifetime bounds on parameters. - Drain { - iter: RawBuckets { - raw, - elems_left, - marker: marker::PhantomData, - }, - table: NonNull::from(self), - marker: marker::PhantomData, - } - } - - /// Drops buckets in reverse order. It leaves the table in an inconsistent - /// state and should only be used for dropping the table's remaining - /// entries. It's used in the implementation of Drop. - unsafe fn rev_drop_buckets(&mut self) { - // initialize the raw bucket past the end of the table - let mut raw = self.raw_bucket_at(self.capacity()); - let mut elems_left = self.size; - - while elems_left != 0 { - raw.idx -= 1; - - if *raw.hash() != EMPTY_BUCKET { - elems_left -= 1; - ptr::drop_in_place(raw.pair()); - } - } - } - - /// Set the table tag - pub fn set_tag(&mut self, value: bool) { - self.hashes.set_tag(value) - } - - /// Get the table tag - pub fn tag(&self) -> bool { - self.hashes.tag() - } -} - -/// A raw iterator. The basis for some other iterators in this module. Although -/// this interface is safe, it's not used outside this module. -struct RawBuckets<'a, K, V> { - raw: RawBucket<K, V>, - elems_left: usize, - - // Strictly speaking, this should be &'a (K,V), but that would - // require that K:'a, and we often use RawBuckets<'static...> for - // move iterations, so that messes up a lot of other things. So - // just use `&'a (K,V)` as this is not a publicly exposed type - // anyway. - marker: marker::PhantomData<&'a ()>, -} - -// FIXME(#26925) Remove in favor of `#[derive(Clone)]` -impl<'a, K, V> Clone for RawBuckets<'a, K, V> { - fn clone(&self) -> RawBuckets<'a, K, V> { - RawBuckets { - raw: self.raw, - elems_left: self.elems_left, - marker: marker::PhantomData, - } - } -} - - -impl<'a, K, V> Iterator for RawBuckets<'a, K, V> { - type Item = RawBucket<K, V>; - - fn next(&mut self) -> Option<RawBucket<K, V>> { - if self.elems_left == 0 { - return None; - } - - loop { - unsafe { - let item = self.raw; - self.raw.idx += 1; - if *item.hash() != EMPTY_BUCKET { - self.elems_left -= 1; - return Some(item); - } - } - } - } - - fn size_hint(&self) -> (usize, Option<usize>) { - (self.elems_left, Some(self.elems_left)) - } -} - -impl<'a, K, V> ExactSizeIterator for RawBuckets<'a, K, V> { - fn len(&self) -> usize { - self.elems_left - } -} - -/// Iterator over shared references to entries in a table. -pub struct Iter<'a, K: 'a, V: 'a> { - iter: RawBuckets<'a, K, V>, -} - -unsafe impl<'a, K: Sync, V: Sync> Sync for Iter<'a, K, V> {} -unsafe impl<'a, K: Sync, V: Sync> Send for Iter<'a, K, V> {} - -// FIXME(#26925) Remove in favor of `#[derive(Clone)]` -impl<'a, K, V> Clone for Iter<'a, K, V> { - fn clone(&self) -> Iter<'a, K, V> { - Iter { - iter: self.iter.clone(), - } - } -} - -/// Iterator over mutable references to entries in a table. -pub struct IterMut<'a, K: 'a, V: 'a> { - iter: RawBuckets<'a, K, V>, - // To ensure invariance with respect to V - _marker: marker::PhantomData<&'a mut V>, -} - -unsafe impl<'a, K: Sync, V: Sync> Sync for IterMut<'a, K, V> {} -// Both K: Sync and K: Send are correct for IterMut's Send impl, -// but Send is the more useful bound -unsafe impl<'a, K: Send, V: Send> Send for IterMut<'a, K, V> {} - -impl<'a, K: 'a, V: 'a> IterMut<'a, K, V> { - pub fn iter(&self) -> Iter<K, V> { - Iter { - iter: self.iter.clone(), - } - } -} - -/// Iterator over the entries in a table, consuming the table. -pub struct IntoIter<K, V> { - table: RawTable<K, V>, - iter: RawBuckets<'static, K, V>, -} - -unsafe impl<K: Sync, V: Sync> Sync for IntoIter<K, V> {} -unsafe impl<K: Send, V: Send> Send for IntoIter<K, V> {} - -impl<K, V> IntoIter<K, V> { - pub fn iter(&self) -> Iter<K, V> { - Iter { - iter: self.iter.clone(), - } - } -} - -/// Iterator over the entries in a table, clearing the table. -pub struct Drain<'a, K: 'a, V: 'a> { - table: NonNull<RawTable<K, V>>, - iter: RawBuckets<'static, K, V>, - marker: marker::PhantomData<&'a RawTable<K, V>>, -} - -unsafe impl<'a, K: Sync, V: Sync> Sync for Drain<'a, K, V> {} -unsafe impl<'a, K: Send, V: Send> Send for Drain<'a, K, V> {} - -impl<'a, K, V> Drain<'a, K, V> { - pub fn iter(&self) -> Iter<K, V> { - Iter { - iter: self.iter.clone(), - } - } -} - -impl<'a, K, V> Iterator for Iter<'a, K, V> { - type Item = (&'a K, &'a V); - - fn next(&mut self) -> Option<(&'a K, &'a V)> { - self.iter.next().map(|raw| unsafe { - let pair_ptr = raw.pair(); - (&(*pair_ptr).0, &(*pair_ptr).1) - }) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} - -impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> { - fn len(&self) -> usize { - self.iter.len() - } -} - -impl<'a, K, V> Iterator for IterMut<'a, K, V> { - type Item = (&'a K, &'a mut V); - - fn next(&mut self) -> Option<(&'a K, &'a mut V)> { - self.iter.next().map(|raw| unsafe { - let pair_ptr = raw.pair(); - (&(*pair_ptr).0, &mut (*pair_ptr).1) - }) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} - -impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> { - fn len(&self) -> usize { - self.iter.len() - } -} - -impl<K, V> Iterator for IntoIter<K, V> { - type Item = (SafeHash, K, V); - - fn next(&mut self) -> Option<(SafeHash, K, V)> { - self.iter.next().map(|raw| { - self.table.size -= 1; - unsafe { - let (k, v) = ptr::read(raw.pair()); - (SafeHash { hash: *raw.hash() }, k, v) - } - }) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} - -impl<K, V> ExactSizeIterator for IntoIter<K, V> { - fn len(&self) -> usize { - self.iter().len() - } -} - -impl<'a, K, V> Iterator for Drain<'a, K, V> { - type Item = (SafeHash, K, V); - - #[inline] - fn next(&mut self) -> Option<(SafeHash, K, V)> { - self.iter.next().map(|raw| { - unsafe { - self.table.as_mut().size -= 1; - let (k, v) = ptr::read(raw.pair()); - (SafeHash { hash: ptr::replace(&mut *raw.hash(), EMPTY_BUCKET) }, k, v) - } - }) - } - - fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() - } -} - -impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> { - fn len(&self) -> usize { - self.iter.len() - } -} - -impl<'a, K: 'a, V: 'a> Drop for Drain<'a, K, V> { - fn drop(&mut self) { - self.for_each(drop); - } -} - -impl<K: Clone, V: Clone> Clone for RawTable<K, V> { - fn clone(&self) -> RawTable<K, V> { - unsafe { - let cap = self.capacity(); - let mut new_ht = RawTable::new_uninitialized(cap); - - let mut new_buckets = new_ht.raw_bucket_at(0); - let mut buckets = self.raw_bucket_at(0); - while buckets.idx < cap { - *new_buckets.hash() = *buckets.hash(); - if *new_buckets.hash() != EMPTY_BUCKET { - let pair_ptr = buckets.pair(); - let kv = ((*pair_ptr).0.clone(), (*pair_ptr).1.clone()); - ptr::write(new_buckets.pair(), kv); - } - buckets.idx += 1; - new_buckets.idx += 1; - } - - new_ht.size = self.size(); - new_ht.set_tag(self.tag()); - - new_ht - } - } -} - -unsafe impl<#[may_dangle] K, #[may_dangle] V> Drop for RawTable<K, V> { - fn drop(&mut self) { - if self.capacity() == 0 { - return; - } - - // This is done in reverse because we've likely partially taken - // some elements out with `.into_iter()` from the front. - // Check if the size is 0, so we don't do a useless scan when - // dropping empty tables such as on resize. - // Also avoid double drop of elements that have been already moved out. - unsafe { - if needs_drop::<(K, V)>() { - // avoid linear runtime for types that don't need drop - self.rev_drop_buckets(); - } - } - - let (layout, _) = calculate_layout::<K, V>(self.capacity()) - .unwrap_or_else(|_| unsafe { hint::unreachable_unchecked() }); - unsafe { - Global.dealloc(NonNull::new_unchecked(self.hashes.ptr()).cast(), layout); - // Remember how everything was allocated out of one buffer - // during initialization? We only need one call to free here. - } - } -} |