diff options
| author | bors <bors@rust-lang.org> | 2014-09-05 17:36:25 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2014-09-05 17:36:25 +0000 |
| commit | 82c052794d4234752f0154c150d0b40779240db4 (patch) | |
| tree | e3005b0c477dd47087b10d1243822592d40522ac | |
| parent | 074d3da7b09883658cd0d52d53ebac7ee74e9e28 (diff) | |
| parent | 0ad4644ae1474b5443e34d273e5553612c6d9364 (diff) | |
| download | rust-82c052794d4234752f0154c150d0b40779240db4.tar.gz rust-82c052794d4234752f0154c150d0b40779240db4.zip | |
auto merge of #16628 : pczarn/rust/hashmap-opt, r=nikomatsakis
This is #15720, rebased and reopened. cc @nikomatsakis
| -rw-r--r-- | src/librustc/lint/context.rs | 6 | ||||
| -rw-r--r-- | src/librustdoc/html/render.rs | 2 | ||||
| -rw-r--r-- | src/libstd/collections/hashmap.rs | 3105 | ||||
| -rw-r--r-- | src/libstd/collections/hashmap/bench.rs | 130 | ||||
| -rw-r--r-- | src/libstd/collections/hashmap/map.rs | 2017 | ||||
| -rw-r--r-- | src/libstd/collections/hashmap/mod.rs | 28 | ||||
| -rw-r--r-- | src/libstd/collections/hashmap/set.rs | 703 | ||||
| -rw-r--r-- | src/libstd/collections/hashmap/table.rs | 896 | ||||
| -rw-r--r-- | src/test/run-fail/hashmap-capacity-overflow.rs | 21 |
9 files changed, 3800 insertions, 3108 deletions
diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs index b40916dcc30..18e44cbac37 100644 --- a/src/librustc/lint/context.rs +++ b/src/librustc/lint/context.rs @@ -103,7 +103,9 @@ impl LintStore { } pub fn get_lint_groups<'t>(&'t self) -> Vec<(&'static str, Vec<LintId>, bool)> { - self.lint_groups.iter().map(|(k, &(ref v, b))| (*k, v.clone(), b)).collect() + self.lint_groups.iter().map(|(k, v)| (*k, + v.ref0().clone(), + *v.ref1())).collect() } pub fn register_pass(&mut self, sess: Option<&Session>, @@ -210,7 +212,7 @@ impl LintStore { match self.by_name.find_equiv(&lint_name.as_slice()) { Some(&lint_id) => self.set_level(lint_id, (level, CommandLine)), None => { - match self.lint_groups.iter().map(|(&x, &(ref y, _))| (x, y.clone())) + match self.lint_groups.iter().map(|(&x, pair)| (x, pair.ref0().clone())) .collect::<HashMap<&'static str, Vec<LintId>>>() .find_equiv(&lint_name.as_slice()) { Some(v) => { diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs index 74ea5af0f1c..77e0a641e18 100644 --- a/src/librustdoc/html/render.rs +++ b/src/librustdoc/html/render.rs @@ -312,7 +312,7 @@ pub fn run(mut krate: clean::Crate, external_html: &ExternalHtml, dst: Path) -> }).unwrap_or(HashMap::new()); let mut cache = Cache { impls: HashMap::new(), - external_paths: paths.iter().map(|(&k, &(ref v, _))| (k, v.clone())) + external_paths: paths.iter().map(|(&k, v)| (k, v.ref0().clone())) .collect(), paths: paths, implementors: HashMap::new(), diff --git a/src/libstd/collections/hashmap.rs b/src/libstd/collections/hashmap.rs deleted file mode 100644 index 1985128c4e3..00000000000 --- a/src/libstd/collections/hashmap.rs +++ /dev/null @@ -1,3105 +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. -// -// ignore-lexer-test FIXME #15883 - -//! Unordered containers, implemented as hash-tables (`HashSet` and `HashMap` types) - -use clone::Clone; -use cmp::{max, Eq, Equiv, PartialEq}; -use collections::{Collection, Mutable, Set, MutableSet, Map, MutableMap}; -use default::Default; -use fmt::Show; -use fmt; -use hash::{Hash, Hasher, RandomSipHasher}; -use iter::{Iterator, FilterMap, Chain, Repeat, Zip, Extendable}; -use iter::{range, range_inclusive, FromIterator}; -use iter; -use mem::replace; -use num; -use option::{Some, None, Option}; -use result::{Ok, Err}; -use ops::Index; - -mod table { - use clone::Clone; - use cmp; - use hash::{Hash, Hasher}; - use iter::range_step_inclusive; - use iter::{Iterator, range}; - use kinds::marker; - use mem::{min_align_of, size_of}; - use mem::{overwrite, transmute}; - use num::{CheckedMul, is_power_of_two}; - use ops::Drop; - use option::{Some, None, Option}; - use ptr::RawPtr; - use ptr::set_memory; - use ptr; - use rt::heap::{allocate, deallocate}; - - static EMPTY_BUCKET: u64 = 0u64; - - /// The raw hashtable, providing safe-ish access to the unzipped and highly - /// optimized arrays of hashes, keys, and values. - /// - /// This design uses less memory and 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. - /// - /// Key invariants of this structure: - /// - /// - if hashes[i] == EMPTY_BUCKET, then keys[i] and vals[i] have - /// 'undefined' contents. Don't read from them. This invariant is - /// enforced outside this module with the `EmptyIndex`, `FullIndex`, - /// and `SafeHash` types. - /// - /// - An `EmptyIndex` is only constructed for a bucket at an index with - /// a hash of EMPTY_BUCKET. - /// - /// - A `FullIndex` is only constructed for a bucket 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". - /// - /// - All three "arrays represented by pointers" are the same length: - /// `capacity`. This is set at creation and never changes. The arrays - /// are unzipped to save space (we don't have to pay for the padding - /// between odd sized elements, such as in a map from u64 to u8), and - /// be more cache aware (scanning through 8 hashes brings in 2 cache - /// lines, since they're all right beside each other). - /// - /// 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>>`. - /// - /// FIXME(cgaebel): - /// - /// Feb 11, 2014: This hashtable was just implemented, and, hard as I tried, - /// isn't yet totally safe. There's a "known exploit" that you can create - /// multiple FullIndexes for a bucket, `take` one, and then still `take` - /// the other causing undefined behavior. Currently, there's no story - /// for how to protect against this statically. Therefore, there are asserts - /// on `take`, `get`, `get_mut`, and `put` which check the bucket state. - /// With time, and when we're confident this works correctly, they should - /// be removed. Also, the bounds check in `peek` is especially painful, - /// as that's called in the innermost loops of the hashtable and has the - /// potential to be a major performance drain. Remove this too. - /// - /// Or, better than remove, only enable these checks for debug builds. - /// There's currently no "debug-only" asserts in rust, so if you're reading - /// this and going "what? of course there are debug-only asserts!", then - /// please make this use them! - #[unsafe_no_drop_flag] - pub struct RawTable<K, V> { - capacity: uint, - size: uint, - hashes: *mut u64, - keys: *mut K, - vals: *mut V, - } - - /// Represents an index into a `RawTable` with no key or value in it. - pub struct EmptyIndex { - idx: int, - nocopy: marker::NoCopy, - } - - /// Represents an index into a `RawTable` with a key, value, and hash - /// in it. - pub struct FullIndex { - idx: int, - hash: SafeHash, - nocopy: marker::NoCopy, - } - - impl FullIndex { - /// Since we get the hash for free whenever we check the bucket state, - /// this function is provided for fast access, letting us avoid - /// redundant trips back to the hashtable. - #[inline(always)] - pub fn hash(&self) -> SafeHash { self.hash } - - /// Same comment as with `hash`. - #[inline(always)] - pub fn raw_index(&self) -> uint { self.idx as uint } - } - - /// Represents the state of a bucket: it can either have a key/value - /// pair (be full) or not (be empty). You cannot `take` empty buckets, - /// and you cannot `put` into full buckets. - pub enum BucketState { - Empty(EmptyIndex), - Full(FullIndex), - } - - /// A hash that is not zero, since we use a hash of zero to represent empty - /// buckets. - #[deriving(PartialEq)] - pub struct SafeHash { - hash: u64, - } - - impl SafeHash { - /// Peek at the hash value, which is guaranteed to be non-zero. - #[inline(always)] - pub fn inspect(&self) -> u64 { self.hash } - } - - /// 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: Hash<S>, S, H: Hasher<S>>(hasher: &H, t: &T) -> SafeHash { - match hasher.hash(t) { - // This constant is exceedingly likely to hash to the same - // bucket, but it won't be counted as empty! - EMPTY_BUCKET => SafeHash { hash: 0x8000_0000_0000_0000 }, - h => SafeHash { hash: h }, - } - } - - fn round_up_to_next(unrounded: uint, target_alignment: uint) -> uint { - assert!(is_power_of_two(target_alignment)); - (unrounded + target_alignment - 1) & !(target_alignment - 1) - } - - #[test] - fn test_rounding() { - assert_eq!(round_up_to_next(0, 4), 0); - assert_eq!(round_up_to_next(1, 4), 4); - assert_eq!(round_up_to_next(2, 4), 4); - assert_eq!(round_up_to_next(3, 4), 4); - assert_eq!(round_up_to_next(4, 4), 4); - assert_eq!(round_up_to_next(5, 4), 8); - } - - // Returns a tuple of (minimum required malloc alignment, hash_offset, - // key_offset, val_offset, array_size), from the start of a mallocated array. - fn calculate_offsets( - hash_size: uint, hash_align: uint, - keys_size: uint, keys_align: uint, - vals_size: uint, vals_align: uint) -> (uint, uint, uint, uint, uint) { - - let hash_offset = 0; - let end_of_hashes = hash_offset + hash_size; - - let keys_offset = round_up_to_next(end_of_hashes, keys_align); - let end_of_keys = keys_offset + keys_size; - - let vals_offset = round_up_to_next(end_of_keys, vals_align); - let end_of_vals = vals_offset + vals_size; - - let min_align = cmp::max(hash_align, cmp::max(keys_align, vals_align)); - - (min_align, hash_offset, keys_offset, vals_offset, end_of_vals) - } - - #[test] - fn test_offset_calculation() { - assert_eq!(calculate_offsets(128, 8, 15, 1, 4, 4 ), (8, 0, 128, 144, 148)); - assert_eq!(calculate_offsets(3, 1, 2, 1, 1, 1 ), (1, 0, 3, 5, 6)); - assert_eq!(calculate_offsets(6, 2, 12, 4, 24, 8), (8, 0, 8, 24, 48)); - } - - 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. - unsafe fn new_uninitialized(capacity: uint) -> RawTable<K, V> { - let hashes_size = capacity.checked_mul(&size_of::<u64>()) - .expect("capacity overflow"); - let keys_size = capacity.checked_mul(&size_of::< K >()) - .expect("capacity overflow"); - let vals_size = capacity.checked_mul(&size_of::< V >()) - .expect("capacity overflow"); - - // Allocating hashmaps is a little tricky. We need to allocate three - // 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. - // - // This is great in theory, but in practice getting the alignment - // right is a little subtle. Therefore, calculating offsets has been - // factored out into a different function. - let (malloc_alignment, hash_offset, keys_offset, vals_offset, size) = - calculate_offsets( - hashes_size, min_align_of::<u64>(), - keys_size, min_align_of::< K >(), - vals_size, min_align_of::< V >()); - - let buffer = allocate(size, malloc_alignment); - - let hashes = buffer.offset(hash_offset as int) as *mut u64; - let keys = buffer.offset(keys_offset as int) as *mut K; - let vals = buffer.offset(vals_offset as int) as *mut V; - - RawTable { - capacity: capacity, - size: 0, - hashes: hashes, - keys: keys, - vals: vals, - } - } - - /// Creates a new raw table from a given capacity. All buckets are - /// initially empty. - #[allow(experimental)] - pub fn new(capacity: uint) -> RawTable<K, V> { - unsafe { - let ret = RawTable::new_uninitialized(capacity); - set_memory(ret.hashes, 0u8, capacity); - ret - } - } - - /// Reads a bucket at a given index, returning an enum indicating whether - /// there's anything there or not. You need to match on this enum to get - /// the appropriate types to pass on to most of the other functions in - /// this module. - pub fn peek(&self, index: uint) -> BucketState { - debug_assert!(index < self.capacity); - - let idx = index as int; - let hash = unsafe { *self.hashes.offset(idx) }; - - let nocopy = marker::NoCopy; - - match hash { - EMPTY_BUCKET => - Empty(EmptyIndex { - idx: idx, - nocopy: nocopy - }), - full_hash => - Full(FullIndex { - idx: idx, - hash: SafeHash { hash: full_hash }, - nocopy: nocopy, - }) - } - } - - /// Gets references to the key and value at a given index. - pub fn read<'a>(&'a self, index: &FullIndex) -> (&'a K, &'a V) { - let idx = index.idx; - - unsafe { - debug_assert!(*self.hashes.offset(idx) != EMPTY_BUCKET); - (&*self.keys.offset(idx), &*self.vals.offset(idx)) - } - } - - /// Gets references to the key and value at a given index, with the - /// value's reference being mutable. - pub fn read_mut<'a>(&'a mut self, index: &FullIndex) -> (&'a K, &'a mut V) { - let idx = index.idx; - - unsafe { - debug_assert!(*self.hashes.offset(idx) != EMPTY_BUCKET); - (&*self.keys.offset(idx), &mut *self.vals.offset(idx)) - } - } - - /// Read everything, mutably. - pub fn read_all_mut<'a>(&'a mut self, index: &FullIndex) - -> (&'a mut SafeHash, &'a mut K, &'a mut V) { - let idx = index.idx; - - unsafe { - debug_assert!(*self.hashes.offset(idx) != EMPTY_BUCKET); - (transmute(self.hashes.offset(idx)), - &mut *self.keys.offset(idx), &mut *self.vals.offset(idx)) - } - } - - /// Puts a key and value pair, along with the key's hash, into a given - /// index in the hashtable. Note how the `EmptyIndex` is 'moved' into this - /// function, because that slot will no longer be empty when we return! - /// A FullIndex 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, index: EmptyIndex, hash: SafeHash, k: K, v: V) -> FullIndex { - let idx = index.idx; - - unsafe { - debug_assert_eq!(*self.hashes.offset(idx), EMPTY_BUCKET); - *self.hashes.offset(idx) = hash.inspect(); - overwrite(&mut *self.keys.offset(idx), k); - overwrite(&mut *self.vals.offset(idx), v); - } - - self.size += 1; - - FullIndex { idx: idx, hash: hash, nocopy: marker::NoCopy } - } - - /// Removes a key and value from the hashtable. - /// - /// This works similarly to `put`, building an `EmptyIndex` out of the - /// taken FullIndex. - pub fn take(&mut self, index: FullIndex) -> (EmptyIndex, K, V) { - let idx = index.idx; - - unsafe { - debug_assert!(*self.hashes.offset(idx) != EMPTY_BUCKET); - - *self.hashes.offset(idx) = EMPTY_BUCKET; - - // Drop the mutable constraint. - let keys = self.keys as *const K; - let vals = self.vals as *const V; - - let k = ptr::read(keys.offset(idx)); - let v = ptr::read(vals.offset(idx)); - - self.size -= 1; - - (EmptyIndex { idx: idx, nocopy: marker::NoCopy }, k, v) - } - } - - /// The hashtable's capacity, similar to a vector's. - pub fn capacity(&self) -> uint { - self.capacity - } - - /// The number of elements ever `put` in the hashtable, minus the number - /// of elements ever `take`n. - pub fn size(&self) -> uint { - self.size - } - - pub fn iter<'a>(&'a self) -> Entries<'a, K, V> { - Entries { table: self, idx: 0, elems_seen: 0 } - } - - pub fn mut_iter<'a>(&'a mut self) -> MutEntries<'a, K, V> { - MutEntries { table: self, idx: 0, elems_seen: 0 } - } - - pub fn move_iter(self) -> MoveEntries<K, V> { - MoveEntries { table: self, idx: 0 } - } - } - - // `read_all_mut` casts a `*u64` to a `*SafeHash`. Since we statically - // ensure that a `FullIndex` points to an index with a non-zero hash, - // and a `SafeHash` is just a `u64` with a different name, this is - // safe. - // - // This test ensures that a `SafeHash` really IS the same size as a - // `u64`. If you need to change the size of `SafeHash` (and - // consequently made this test fail), `read_all_mut` needs to be - // modified to no longer assume this. - #[test] - fn can_alias_safehash_as_u64() { - assert_eq!(size_of::<SafeHash>(), size_of::<u64>()) - } - - /// Iterator over shared references to entries in a table. - pub struct Entries<'a, K:'a, V:'a> { - table: &'a RawTable<K, V>, - idx: uint, - elems_seen: uint, - } - - /// Iterator over mutable references to entries in a table. - pub struct MutEntries<'a, K:'a, V:'a> { - table: &'a mut RawTable<K, V>, - idx: uint, - elems_seen: uint, - } - - /// Iterator over the entries in a table, consuming the table. - pub struct MoveEntries<K, V> { - table: RawTable<K, V>, - idx: uint - } - - impl<'a, K, V> Iterator<(&'a K, &'a V)> for Entries<'a, K, V> { - fn next(&mut self) -> Option<(&'a K, &'a V)> { - while self.idx < self.table.capacity() { - let i = self.idx; - self.idx += 1; - - match self.table.peek(i) { - Empty(_) => {}, - Full(idx) => { - self.elems_seen += 1; - return Some(self.table.read(&idx)); - } - } - } - - None - } - - fn size_hint(&self) -> (uint, Option<uint>) { - let size = self.table.size() - self.elems_seen; - (size, Some(size)) - } - } - - impl<'a, K, V> Iterator<(&'a K, &'a mut V)> for MutEntries<'a, K, V> { - fn next(&mut self) -> Option<(&'a K, &'a mut V)> { - while self.idx < self.table.capacity() { - let i = self.idx; - self.idx += 1; - - match self.table.peek(i) { - Empty(_) => {}, - // the transmute here fixes: - // error: lifetime of `self` is too short to guarantee its contents - // can be safely reborrowed - Full(idx) => unsafe { - self.elems_seen += 1; - return Some(transmute(self.table.read_mut(&idx))); - } - } - } - - None - } - - fn size_hint(&self) -> (uint, Option<uint>) { - let size = self.table.size() - self.elems_seen; - (size, Some(size)) - } - } - - impl<K, V> Iterator<(SafeHash, K, V)> for MoveEntries<K, V> { - fn next(&mut self) -> Option<(SafeHash, K, V)> { - while self.idx < self.table.capacity() { - let i = self.idx; - self.idx += 1; - - match self.table.peek(i) { - Empty(_) => {}, - Full(idx) => { - let h = idx.hash(); - let (_, k, v) = self.table.take(idx); - return Some((h, k, v)); - } - } - } - - None - } - - fn size_hint(&self) -> (uint, Option<uint>) { - let size = self.table.size(); - (size, Some(size)) - } - } - - impl<K: Clone, V: Clone> Clone for RawTable<K, V> { - fn clone(&self) -> RawTable<K, V> { - unsafe { - let mut new_ht = RawTable::new_uninitialized(self.capacity()); - - for i in range(0, self.capacity()) { - match self.peek(i) { - Empty(_) => { - *new_ht.hashes.offset(i as int) = EMPTY_BUCKET; - }, - Full(idx) => { - let hash = idx.hash().inspect(); - let (k, v) = self.read(&idx); - *new_ht.hashes.offset(i as int) = hash; - overwrite(&mut *new_ht.keys.offset(i as int), (*k).clone()); - overwrite(&mut *new_ht.vals.offset(i as int), (*v).clone()); - } - } - } - - new_ht.size = self.size(); - - new_ht - } - } - } - - #[unsafe_destructor] - impl<K, V> Drop for RawTable<K, V> { - fn drop(&mut self) { - // This is in reverse because we're likely to have partially taken - // some elements out with `.move_iter()` from the front. - for i in range_step_inclusive(self.capacity as int - 1, 0, -1) { - // Check if the size is 0, so we don't do a useless scan when - // dropping empty tables such as on resize. - if self.size == 0 { break } - - match self.peek(i as uint) { - Empty(_) => {}, - Full(idx) => { self.take(idx); } - } - } - - assert_eq!(self.size, 0); - - if self.hashes.is_not_null() { - let hashes_size = self.capacity * size_of::<u64>(); - let keys_size = self.capacity * size_of::<K>(); - let vals_size = self.capacity * size_of::<V>(); - let (align, _, _, _, size) = calculate_offsets(hashes_size, min_align_of::<u64>(), - keys_size, min_align_of::<K>(), - vals_size, min_align_of::<V>()); - - unsafe { - deallocate(self.hashes as *mut u8, size, align); - // Remember how everything was allocated out of one buffer - // during initialization? We only need one call to free here. - } - - self.hashes = RawPtr::null(); - } - } - } -} - -static INITIAL_LOG2_CAP: uint = 5; -static INITIAL_CAPACITY: uint = 1 << INITIAL_LOG2_CAP; // 2^5 - -/// The default behavior of HashMap implements a load factor of 90.9%. -/// This behavior is characterized by the following conditions: -/// -/// - if `size * 1.1 < cap < size * 4` then shouldn't resize -/// - if `cap < minimum_capacity * 2` then shouldn't shrink -#[deriving(Clone)] -struct DefaultResizePolicy { - /// Doubled minimal capacity. The capacity must never drop below - /// the minimum capacity. (The check happens before the capacity - /// is potentially halved.) - minimum_capacity2: uint -} - -impl DefaultResizePolicy { - fn new(new_capacity: uint) -> DefaultResizePolicy { - DefaultResizePolicy { - minimum_capacity2: new_capacity << 1 - } - } - - #[inline] - fn capacity_range(&self, new_size: uint) -> (uint, uint) { - ((new_size * 11) / 10, max(new_size << 3, self.minimum_capacity2)) - } - - #[inline] - fn reserve(&mut self, new_capacity: uint) { - self.minimum_capacity2 = new_capacity << 1; - } -} - -// The main performance trick in this hashmap is called Robin Hood Hashing. -// It gains its excellent performance from one key invariant: -// -// If an insertion collides with an existing element, and that elements -// "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. -// -// 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!) -// ============================= -// -// The paper cited below mentions an implementation which keeps track of the -// distance-to-initial-bucket histogram. I'm suspicious of this approach because -// it requires maintaining an internal map. If this map were replaced with a -// hashmap, it would be faster, but now our data structure is self-referential -// and blows up. Also, this allows very good first guesses, but array accesses -// are no longer linear and in one direction, as we have now. There is also -// memory and cache pressure that this map would entail that would be very -// difficult to properly see in a microbenchmark. -// -// 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. -// -// There's also an "optimization" that has been omitted regarding how the -// hashtable allocates. The vector type has set the expectation that a hashtable -// which never has an element inserted should not allocate. I'm suspicious of -// implementing this for hashtables, because supporting it has no performance -// benefit over using an `Option<HashMap<K, V>>`, and is significantly more -// complicated. - -/// A hash map implementation which uses linear probing with Robin -/// Hood bucket stealing. -/// -/// The hashes are all keyed by the task-local random number generator -/// on creation by default. This means that the ordering of the keys is -/// randomized, but makes the tables more resistant to -/// denial-of-service attacks (Hash DoS). This behaviour can be -/// overridden with one of the constructors. -/// -/// It is required that the keys implement the `Eq` and `Hash` traits, although -/// this can frequently be achieved by using `#[deriving(Eq, Hash)]`. -/// -/// 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/) -/// -/// # Example -/// -/// ``` -/// use std::collections::HashMap; -/// -/// // type inference lets us omit an explicit type signature (which -/// // would be `HashMap<&str, &str>` in this example). -/// let mut book_reviews = HashMap::new(); -/// -/// // review some books. -/// book_reviews.insert("Adventures of Huckleberry Finn", "My favorite book."); -/// book_reviews.insert("Grimms' Fairy Tales", "Masterpiece."); -/// book_reviews.insert("Pride and Prejudice", "Very enjoyable."); -/// book_reviews.insert("The Adventures of Sherlock Holmes", "Eye lyked it alot."); -/// -/// // check for a specific one. -/// 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.iter() { -/// match book_reviews.find(book) { -/// Some(review) => println!("{}: {}", *book, *review), -/// None => println!("{} is unreviewed.", *book) -/// } -/// } -/// -/// // iterate over everything. -/// for (book, review) in book_reviews.iter() { -/// println!("{}: \"{}\"", *book, *review); -/// } -/// ``` -/// -/// The easiest way to use `HashMap` with a custom type is to derive `Eq` and `Hash`. -/// We must also derive `PartialEq`. -/// -/// ``` -/// use std::collections::HashMap; -/// -/// #[deriving(Hash, Eq, PartialEq, Show)] -/// struct Viking<'a> { -/// name: &'a str, -/// power: uint, -/// } -/// -/// let mut vikings = HashMap::new(); -/// -/// vikings.insert("Norway", Viking { name: "Einar", power: 9u }); -/// vikings.insert("Denmark", Viking { name: "Olaf", power: 4u }); -/// vikings.insert("Iceland", Viking { name: "Harald", power: 8u }); -/// -/// // Use derived implementation to print the vikings. -/// for (land, viking) in vikings.iter() { -/// println!("{} at {}", viking, land); -/// } -/// ``` -#[deriving(Clone)] -pub struct HashMap<K, V, H = RandomSipHasher> { - // All hashes are keyed on these values, to prevent hash collision attacks. - hasher: H, - - table: table::RawTable<K, V>, - - // We keep this at the end since it might as well have tail padding. - resize_policy: DefaultResizePolicy, -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> { - // Probe the `idx`th bucket for a given hash, returning the index of the - // target bucket. - // - // This exploits the power-of-two size of the hashtable. As long as this - // is always true, we can use a bitmask of cap-1 to do modular arithmetic. - // - // Prefer using this with increasing values of `idx` rather than repeatedly - // calling `probe_next`. This reduces data-dependencies between loops, which - // can help the optimizer, and certainly won't hurt it. `probe_next` is - // simply for convenience, and is no more efficient than `probe`. - fn probe(&self, hash: &table::SafeHash, idx: uint) -> uint { - let hash_mask = self.table.capacity() - 1; - - // So I heard a rumor that unsigned overflow is safe in rust.. - ((hash.inspect() as uint) + idx) & hash_mask - } - - // Generate the next probe in a sequence. Prefer using 'probe' by itself, - // but this can sometimes be useful. - fn probe_next(&self, probe: uint) -> uint { - let hash_mask = self.table.capacity() - 1; - (probe + 1) & hash_mask - } - - fn make_hash<X: Hash<S>>(&self, x: &X) -> table::SafeHash { - table::make_hash(&self.hasher, x) - } - - /// Get the distance of the bucket at the given index that it lies - /// from its 'ideal' location. - /// - /// In the cited blog posts above, this is called the "distance to - /// initial bucket", or DIB. - fn bucket_distance(&self, index_of_elem: &table::FullIndex) -> uint { - // where the hash of the element that happens to reside at - // `index_of_elem` tried to place itself first. - let first_probe_index = self.probe(&index_of_elem.hash(), 0); - - let raw_index = index_of_elem.raw_index(); - - if first_probe_index <= raw_index { - // probe just went forward - raw_index - first_probe_index - } else { - // probe wrapped around the hashtable - raw_index + (self.table.capacity() - first_probe_index) - } - } - - /// Search for a pre-hashed key. - fn search_hashed_generic(&self, hash: &table::SafeHash, is_match: |&K| -> bool) - -> Option<table::FullIndex> { - for num_probes in range(0u, self.table.size()) { - let probe = self.probe(hash, num_probes); - - let idx = match self.table.peek(probe) { - table::Empty(_) => return None, // hit an empty bucket - table::Full(idx) => idx - }; - - // We can finish the search early if we hit any bucket - // with a lower distance to initial bucket than we've probed. - if self.bucket_distance(&idx) < num_probes { return None } - - // If the hash doesn't match, it can't be this one.. - if *hash != idx.hash() { continue } - - let (k, _) = self.table.read(&idx); - - // If the key doesn't match, it can't be this one.. - if !is_match(k) { continue } - - return Some(idx); - } - - return None - } - - fn search_hashed(&self, hash: &table::SafeHash, k: &K) -> Option<table::FullIndex> { - self.search_hashed_generic(hash, |k_| *k == *k_) - } - - fn search_equiv<Q: Hash<S> + Equiv<K>>(&self, q: &Q) -> Option<table::FullIndex> { - self.search_hashed_generic(&self.make_hash(q), |k| q.equiv(k)) - } - - /// 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, use - /// search_hashed. - fn search(&self, k: &K) -> Option<table::FullIndex> { - self.search_hashed(&self.make_hash(k), k) - } - - fn pop_internal(&mut self, starting_index: table::FullIndex) -> Option<V> { - let starting_probe = starting_index.raw_index(); - - let ending_probe = { - let mut probe = self.probe_next(starting_probe); - for _ in range(0u, self.table.size()) { - match self.table.peek(probe) { - table::Empty(_) => {}, // empty bucket. this is the end of our shifting. - table::Full(idx) => { - // Bucket that isn't us, which has a non-zero probe distance. - // This isn't the ending index, so keep searching. - if self.bucket_distance(&idx) != 0 { - probe = self.probe_next(probe); - continue; - } - - // if we do have a bucket_distance of zero, we're at the end - // of what we need to shift. - } - } - break; - } - - probe - }; - - let (_, _, retval) = self.table.take(starting_index); - - let mut probe = starting_probe; - let mut next_probe = self.probe_next(probe); - - // backwards-shift all the elements after our newly-deleted one. - while next_probe != ending_probe { - match self.table.peek(next_probe) { - table::Empty(_) => { - // nothing to shift in. just empty it out. - match self.table.peek(probe) { - table::Empty(_) => {}, - table::Full(idx) => { self.table.take(idx); } - } - }, - table::Full(next_idx) => { - // something to shift. move it over! - let next_hash = next_idx.hash(); - let (_, next_key, next_val) = self.table.take(next_idx); - match self.table.peek(probe) { - table::Empty(idx) => { - self.table.put(idx, next_hash, next_key, next_val); - }, - table::Full(idx) => { - let (emptyidx, _, _) = self.table.take(idx); - self.table.put(emptyidx, next_hash, next_key, next_val); - } - } - } - } - - probe = next_probe; - next_probe = self.probe_next(next_probe); - } - - // Done the backwards shift, but there's still an element left! - // Empty it out. - match self.table.peek(probe) { - table::Empty(_) => {}, - table::Full(idx) => { self.table.take(idx); } - } - - // Now we're done all our shifting. Return the value we grabbed - // earlier. - return Some(retval); - } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Collection for HashMap<K, V, H> { - /// Return the number of elements in the map. - fn len(&self) -> uint { self.table.size() } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Mutable for HashMap<K, V, H> { - /// Clear the map, removing all key-value pairs. Keeps the allocated memory - /// for reuse. - fn clear(&mut self) { - // Prevent reallocations from happening from now on. Makes it possible - // for the map to be reused but has a downside: reserves permanently. - self.resize_policy.reserve(self.table.size()); - - for i in range(0, self.table.capacity()) { - match self.table.peek(i) { - table::Empty(_) => {}, - table::Full(idx) => { self.table.take(idx); } - } - } - } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Map<K, V> for HashMap<K, V, H> { - fn find<'a>(&'a self, k: &K) -> Option<&'a V> { - self.search(k).map(|idx| { - let (_, v) = self.table.read(&idx); - v - }) - } - - fn contains_key(&self, k: &K) -> bool { - self.search(k).is_some() - } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> MutableMap<K, V> for HashMap<K, V, H> { - fn find_mut<'a>(&'a mut self, k: &K) -> Option<&'a mut V> { - match self.search(k) { - None => None, - Some(idx) => { - let (_, v) = self.table.read_mut(&idx); - Some(v) - } - } - } - - fn swap(&mut self, k: K, v: V) -> Option<V> { - let hash = self.make_hash(&k); - let potential_new_size = self.table.size() + 1; - self.make_some_room(potential_new_size); - - for dib in range_inclusive(0u, self.table.size()) { - let probe = self.probe(&hash, dib); - - let idx = match self.table.peek(probe) { - table::Empty(idx) => { - // Found a hole! - self.table.put(idx, hash, k, v); - return None; - }, - table::Full(idx) => idx - }; - - if idx.hash() == hash { - let (bucket_k, bucket_v) = self.table.read_mut(&idx); - if k == *bucket_k { - // Found an existing value. - return Some(replace(bucket_v, v)); - } - } - - let probe_dib = self.bucket_distance(&idx); - - if probe_dib < dib { - // Found a luckier bucket. This implies that the key does not - // already exist in the hashtable. Just do a robin hood - // insertion, then. - self.robin_hood(idx, probe_dib, hash, k, v); - return None; - } - } - - // We really shouldn't be here. - fail!("Internal HashMap error: Out of space."); - } - - fn pop(&mut self, k: &K) -> Option<V> { - if self.table.size() == 0 { - return None - } - - let potential_new_size = self.table.size() - 1; - self.make_some_room(potential_new_size); - - let starting_index = match self.search(k) { - Some(idx) => idx, - None => return None, - }; - - self.pop_internal(starting_index) - } - -} - -impl<K: Hash + Eq, V> HashMap<K, V, RandomSipHasher> { - /// Create an empty HashMap. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map: HashMap<&str, int> = HashMap::new(); - /// ``` - #[inline] - pub fn new() -> HashMap<K, V, RandomSipHasher> { - HashMap::with_capacity(INITIAL_CAPACITY) - } - - /// Creates an empty hash map with the given initial capacity. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map: HashMap<&str, int> = HashMap::with_capacity(10); - /// ``` - #[inline] - pub fn with_capacity(capacity: uint) -> HashMap<K, V, RandomSipHasher> { - let hasher = RandomSipHasher::new(); - HashMap::with_capacity_and_hasher(capacity, hasher) - } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> { - /// Creates an empty hashmap which will use the given hasher to hash keys. - /// - /// The creates map has the default initial capacity. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// use std::hash::sip::SipHasher; - /// - /// let h = SipHasher::new(); - /// let mut map = HashMap::with_hasher(h); - /// map.insert(1i, 2u); - /// ``` - #[inline] - pub fn with_hasher(hasher: H) -> HashMap<K, V, H> { - HashMap::with_capacity_and_hasher(INITIAL_CAPACITY, hasher) - } - - /// Create an empty HashMap with space for at least `capacity` - /// elements, using `hasher` to hash the keys. - /// - /// Warning: `hasher` 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. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// use std::hash::sip::SipHasher; - /// - /// let h = SipHasher::new(); - /// let mut map = HashMap::with_capacity_and_hasher(10, h); - /// map.insert(1i, 2u); - /// ``` - #[inline] - pub fn with_capacity_and_hasher(capacity: uint, hasher: H) -> HashMap<K, V, H> { - let cap = num::next_power_of_two(max(INITIAL_CAPACITY, capacity)); - HashMap { - hasher: hasher, - resize_policy: DefaultResizePolicy::new(cap), - table: table::RawTable::new(cap), - } - } - - /// The hashtable will never try to shrink below this size. You can use - /// this function to reduce reallocations if your hashtable frequently - /// grows and shrinks by large amounts. - /// - /// This function has no effect on the operational semantics of the - /// hashtable, only on performance. - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map: HashMap<&str, int> = HashMap::new(); - /// map.reserve(10); - /// ``` - pub fn reserve(&mut self, new_minimum_capacity: uint) { - let cap = num::next_power_of_two( - max(INITIAL_CAPACITY, new_minimum_capacity)); - - self.resize_policy.reserve(cap); - - if self.table.capacity() < cap { - self.resize(cap); - } - } - - /// Resizes the internal vectors to a new capacity. It's your responsibility to: - /// 1) Make sure the new capacity is enough for all the elements, accounting - /// for the load factor. - /// 2) Ensure new_capacity is a power of two. - fn resize(&mut self, new_capacity: uint) { - assert!(self.table.size() <= new_capacity); - assert!(num::is_power_of_two(new_capacity)); - - let old_table = replace(&mut self.table, table::RawTable::new(new_capacity)); - let old_size = old_table.size(); - - for (h, k, v) in old_table.move_iter() { - self.insert_hashed_nocheck(h, k, v); - } - - assert_eq!(self.table.size(), old_size); - } - - /// Performs any necessary resize operations, such that there's space for - /// new_size elements. - fn make_some_room(&mut self, new_size: uint) { - let (grow_at, shrink_at) = self.resize_policy.capacity_range(new_size); - let cap = self.table.capacity(); - - // An invalid value shouldn't make us run out of space. - debug_assert!(grow_at >= new_size); - - if cap <= grow_at { - let new_capacity = cap << 1; - self.resize(new_capacity); - } else if shrink_at <= cap { - let new_capacity = cap >> 1; - self.resize(new_capacity); - } - } - - /// Perform robin hood bucket stealing at the given 'index'. You must - /// also pass that probe's "distance to initial bucket" so we don't have - /// to recalculate it, as well as the total number of probes already done - /// so we have some sort of upper bound on the number of probes to do. - /// - /// 'hash', 'k', and 'v' are the elements to robin hood into the hashtable. - fn robin_hood(&mut self, mut index: table::FullIndex, mut dib_param: uint, - mut hash: table::SafeHash, mut k: K, mut v: V) { - 'outer: loop { - let (old_hash, old_key, old_val) = { - let (old_hash_ref, old_key_ref, old_val_ref) = - self.table.read_all_mut(&index); - - let old_hash = replace(old_hash_ref, hash); - let old_key = replace(old_key_ref, k); - let old_val = replace(old_val_ref, v); - - (old_hash, old_key, old_val) - }; - - let mut probe = self.probe_next(index.raw_index()); - - for dib in range(dib_param + 1, self.table.size()) { - let full_index = match self.table.peek(probe) { - table::Empty(idx) => { - // Finally. A hole! - self.table.put(idx, old_hash, old_key, old_val); - return; - }, - table::Full(idx) => idx - }; - - let probe_dib = self.bucket_distance(&full_index); - - // Robin hood! Steal the spot. - if probe_dib < dib { - index = full_index; - dib_param = probe_dib; - hash = old_hash; - k = old_key; - v = old_val; - continue 'outer; - } - - probe = self.probe_next(probe); - } - - fail!("HashMap fatal error: 100% load factor?"); - } - } - - /// 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<'a>( - &'a mut self, hash: table::SafeHash, k: K, v: V) -> &'a mut V { - - for dib in range_inclusive(0u, self.table.size()) { - let probe = self.probe(&hash, dib); - - let idx = match self.table.peek(probe) { - table::Empty(idx) => { - // Found a hole! - let fullidx = self.table.put(idx, hash, k, v); - let (_, val) = self.table.read_mut(&fullidx); - return val; - }, - table::Full(idx) => idx - }; - - if idx.hash() == hash { - let (bucket_k, bucket_v) = self.table.read_mut(&idx); - // FIXME #12147 the conditional return confuses - // borrowck if we return bucket_v directly - let bv: *mut V = bucket_v; - if k == *bucket_k { - // Key already exists. Get its reference. - return unsafe {&mut *bv}; - } - } - - let probe_dib = self.bucket_distance(&idx); - - if probe_dib < dib { - // Found a luckier bucket than me. Better steal his spot. - self.robin_hood(idx, probe_dib, hash, k, v); - - // Now that it's stolen, just read the value's pointer - // right out of the table! - match self.table.peek(probe) { - table::Empty(_) => fail!("Just stole a spot, but now that spot's empty."), - table::Full(idx) => { - let (_, v) = self.table.read_mut(&idx); - return v; - } - } - } - } - - // We really shouldn't be here. - fail!("Internal HashMap error: Out of space."); - } - - /// Inserts an element which has already been hashed, returning a reference - /// to that element inside the hashtable. This is more efficient that using - /// `insert`, since the key will not be rehashed. - fn insert_hashed<'a>(&'a mut self, hash: table::SafeHash, k: K, v: V) -> &'a mut V { - let potential_new_size = self.table.size() + 1; - self.make_some_room(potential_new_size); - self.insert_hashed_nocheck(hash, k, v) - } - - /// Return the value corresponding to the key in the map, or insert - /// and return the value if it doesn't exist. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map = HashMap::new(); - /// - /// // Insert 1i with key "a" - /// assert_eq!(*map.find_or_insert("a", 1i), 1); - /// - /// // Find the existing key - /// assert_eq!(*map.find_or_insert("a", -2), 1); - /// ``` - pub fn find_or_insert<'a>(&'a mut self, k: K, v: V) -> &'a mut V { - self.find_with_or_insert_with(k, v, |_k, _v, _a| (), |_k, a| a) - } - - /// Return the value corresponding to the key in the map, or create, - /// insert, and return a new value if it doesn't exist. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map = HashMap::new(); - /// - /// // Insert 10 with key 2 - /// assert_eq!(*map.find_or_insert_with(2i, |&key| 5 * key as uint), 10u); - /// - /// // Find the existing key - /// assert_eq!(*map.find_or_insert_with(2, |&key| key as uint), 10); - /// ``` - pub fn find_or_insert_with<'a>(&'a mut self, k: K, f: |&K| -> V) - -> &'a mut V { - self.find_with_or_insert_with(k, (), |_k, _v, _a| (), |k, _a| f(k)) - } - - /// Insert a key-value pair into the map if the key is not already present. - /// Otherwise, modify the existing value for the key. - /// Returns the new or modified value for the key. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// let mut map = HashMap::new(); - /// - /// // Insert 2 with key "a" - /// assert_eq!(*map.insert_or_update_with("a", 2u, |_key, val| *val = 3), 2); - /// - /// // Update and return the existing value - /// assert_eq!(*map.insert_or_update_with("a", 9, |_key, val| *val = 7), 7); - /// assert_eq!(map["a"], 7); - /// ``` - pub fn insert_or_update_with<'a>( - &'a mut self, - k: K, - v: V, - f: |&K, &mut V|) - -> &'a mut V { - self.find_with_or_insert_with(k, v, |k, v, _a| f(k, v), |_k, a| a) - } - - /// Modify and return the value corresponding to the key in the map, or - /// insert and return a new value if it doesn't exist. - /// - /// This method allows for all insertion behaviours of a hashmap; - /// see methods like - /// [`insert`](../trait.MutableMap.html#tymethod.insert), - /// [`find_or_insert`](#method.find_or_insert) and - /// [`insert_or_update_with`](#method.insert_or_update_with) - /// for less general and more friendly variations of this. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// // map some strings to vectors of strings - /// let mut map = HashMap::new(); - /// map.insert("a key", vec!["value"]); - /// map.insert("z key", vec!["value"]); - /// - /// let new = vec!["a key", "b key", "z key"]; - /// - /// for k in new.move_iter() { - /// map.find_with_or_insert_with( - /// k, "new value", - /// // if the key does exist either prepend or append this - /// // new value based on the first letter of the key. - /// |key, already, new| { - /// if key.as_slice().starts_with("z") { - /// already.insert(0, new); - /// } else { - /// already.push(new); - /// } - /// }, - /// // if the key doesn't exist in the map yet, add it in - /// // the obvious way. - /// |_k, v| vec![v]); - /// } - /// - /// assert_eq!(map.len(), 3); - /// assert_eq!(map["a key"], vec!["value", "new value"]); - /// assert_eq!(map["b key"], vec!["new value"]); - /// assert_eq!(map["z key"], vec!["new value", "value"]); - /// ``` - pub fn find_with_or_insert_with<'a, A>(&'a mut self, - k: K, - a: A, - found: |&K, &mut V, A|, - not_found: |&K, A| -> V) - -> &'a mut V { - let hash = self.make_hash(&k); - match self.search_hashed(&hash, &k) { - None => { - let v = not_found(&k, a); - self.insert_hashed(hash, k, v) - }, - Some(idx) => { - let (_, v_ref) = self.table.read_mut(&idx); - found(&k, v_ref, a); - v_ref - } - } - } - - /// Retrieves a value for the given key. - /// See [`find`](../trait.Map.html#tymethod.find) for a non-failing alternative. - /// - /// # Failure - /// - /// Fails if the key is not present. - /// - /// # Example - /// - /// ``` - /// #![allow(deprecated)] - /// - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1i); - /// assert_eq!(map.get(&"a"), &1); - /// ``` - #[deprecated = "prefer indexing instead, e.g., map[key]"] - pub fn get<'a>(&'a self, k: &K) -> &'a V { - match self.find(k) { - Some(v) => v, - None => fail!("no entry found for key") - } - } - - /// Retrieves a mutable value for the given key. - /// See [`find_mut`](../trait.MutableMap.html#tymethod.find_mut) for a non-failing alternative. - /// - /// # Failure - /// - /// Fails if the key is not present. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1i); - /// { - /// // val will freeze map to prevent usage during its lifetime - /// let val = map.get_mut(&"a"); - /// *val = 40; - /// } - /// assert_eq!(map["a"], 40); - /// - /// // A more direct way could be: - /// *map.get_mut(&"a") = -2; - /// assert_eq!(map["a"], -2); - /// ``` - pub fn get_mut<'a>(&'a mut self, k: &K) -> &'a mut V { - match self.find_mut(k) { - Some(v) => v, - None => fail!("no entry found for key") - } - } - - /// Return true if the map contains a value for the specified key, - /// using equivalence. - /// - /// See [pop_equiv](#method.pop_equiv) for an extended example. - pub fn contains_key_equiv<Q: Hash<S> + Equiv<K>>(&self, key: &Q) -> bool { - self.search_equiv(key).is_some() - } - - /// Return the value corresponding to the key in the map, using - /// equivalence. - /// - /// See [pop_equiv](#method.pop_equiv) for an extended example. - pub fn find_equiv<'a, Q: Hash<S> + Equiv<K>>(&'a self, k: &Q) -> Option<&'a V> { - match self.search_equiv(k) { - None => None, - Some(idx) => { - let (_, v_ref) = self.table.read(&idx); - Some(v_ref) - } - } - } - - /// Remove an equivalent key from the map, returning the value at the - /// key if the key was previously in the map. - /// - /// # Example - /// - /// This is a slightly silly example where we define the number's parity as - /// the equivalence class. It is important that the values hash the same, - /// which is why we override `Hash`. - /// - /// ``` - /// use std::collections::HashMap; - /// use std::hash::Hash; - /// use std::hash::sip::SipState; - /// - /// #[deriving(Eq, PartialEq)] - /// struct EvenOrOdd { - /// num: uint - /// }; - /// - /// impl Hash for EvenOrOdd { - /// fn hash(&self, state: &mut SipState) { - /// let parity = self.num % 2; - /// parity.hash(state); - /// } - /// } - /// - /// impl Equiv<EvenOrOdd> for EvenOrOdd { - /// fn equiv(&self, other: &EvenOrOdd) -> bool { - /// self.num % 2 == other.num % 2 - /// } - /// } - /// - /// let mut map = HashMap::new(); - /// map.insert(EvenOrOdd { num: 3 }, "foo"); - /// - /// assert!(map.contains_key_equiv(&EvenOrOdd { num: 1 })); - /// assert!(!map.contains_key_equiv(&EvenOrOdd { num: 4 })); - /// - /// assert_eq!(map.find_equiv(&EvenOrOdd { num: 5 }), Some(&"foo")); - /// assert_eq!(map.find_equiv(&EvenOrOdd { num: 2 }), None); - /// - /// assert_eq!(map.pop_equiv(&EvenOrOdd { num: 1 }), Some("foo")); - /// assert_eq!(map.pop_equiv(&EvenOrOdd { num: 2 }), None); - /// - /// ``` - #[experimental] - pub fn pop_equiv<Q:Hash<S> + Equiv<K>>(&mut self, k: &Q) -> Option<V> { - if self.table.size() == 0 { - return None - } - - let potential_new_size = self.table.size() - 1; - self.make_some_room(potential_new_size); - - let starting_index = match self.search_equiv(k) { - Some(idx) => idx, - None => return None, - }; - - self.pop_internal(starting_index) - } - - /// An iterator visiting all keys in arbitrary order. - /// Iterator element type is `&'a K`. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1i); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// for key in map.keys() { - /// println!("{}", key); - /// } - /// ``` - pub fn keys<'a>(&'a self) -> Keys<'a, K, V> { - self.iter().map(|(k, _v)| k) - } - - /// An iterator visiting all values in arbitrary order. - /// Iterator element type is `&'a V`. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1i); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// for key in map.values() { - /// println!("{}", key); - /// } - /// ``` - pub fn values<'a>(&'a self) -> Values<'a, K, V> { - self.iter().map(|(_k, v)| v) - } - - /// An iterator visiting all key-value pairs in arbitrary order. - /// Iterator element type is `(&'a K, &'a V)`. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1i); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// for (key, val) in map.iter() { - /// println!("key: {} val: {}", key, val); - /// } - /// ``` - pub fn iter<'a>(&'a self) -> Entries<'a, K, V> { - self.table.iter() - } - - /// An iterator visiting all key-value pairs in arbitrary order, - /// with mutable references to the values. - /// Iterator element type is `(&'a K, &'a mut V)`. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1i); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// // Update all values - /// for (_, val) in map.mut_iter() { - /// *val *= 2; - /// } - /// - /// for (key, val) in map.iter() { - /// println!("key: {} val: {}", key, val); - /// } - /// ``` - pub fn mut_iter<'a>(&'a mut self) -> MutEntries<'a, K, V> { - self.table.mut_iter() - } - - /// 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. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map = HashMap::new(); - /// map.insert("a", 1i); - /// map.insert("b", 2); - /// map.insert("c", 3); - /// - /// // Not possible with .iter() - /// let vec: Vec<(&str, int)> = map.move_iter().collect(); - /// ``` - pub fn move_iter(self) -> MoveEntries<K, V> { - self.table.move_iter().map(|(_, k, v)| (k, v)) - } -} - -impl<K: Eq + Hash<S>, V: Clone, S, H: Hasher<S>> HashMap<K, V, H> { - /// Return a copy of the value corresponding to the key. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<uint, String> = HashMap::new(); - /// map.insert(1u, "foo".to_string()); - /// let s: String = map.find_copy(&1).unwrap(); - /// ``` - pub fn find_copy(&self, k: &K) -> Option<V> { - self.find(k).map(|v| (*v).clone()) - } - - /// Return a copy of the value corresponding to the key. - /// - /// # Failure - /// - /// Fails if the key is not present. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashMap; - /// - /// let mut map: HashMap<uint, String> = HashMap::new(); - /// map.insert(1u, "foo".to_string()); - /// let s: String = map.get_copy(&1); - /// ``` - pub fn get_copy(&self, k: &K) -> V { - (*self.get(k)).clone() - } -} - -impl<K: Eq + Hash<S>, V: PartialEq, S, H: Hasher<S>> PartialEq for HashMap<K, V, H> { - fn eq(&self, other: &HashMap<K, V, H>) -> bool { - if self.len() != other.len() { return false; } - - self.iter() - .all(|(key, value)| { - match other.find(key) { - None => false, - Some(v) => *value == *v - } - }) - } -} - -impl<K: Eq + Hash<S>, V: Eq, S, H: Hasher<S>> Eq for HashMap<K, V, H> {} - -impl<K: Eq + Hash<S> + Show, V: Show, S, H: Hasher<S>> Show for HashMap<K, V, H> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - try!(write!(f, "{{")); - - for (i, (k, v)) in self.iter().enumerate() { - if i != 0 { try!(write!(f, ", ")); } - try!(write!(f, "{}: {}", *k, *v)); - } - - write!(f, "}}") - } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> Default for HashMap<K, V, H> { - fn default() -> HashMap<K, V, H> { - HashMap::with_hasher(Default::default()) - } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Index<K, V> for HashMap<K, V, H> { - #[inline] - fn index<'a>(&'a self, index: &K) -> &'a V { - self.get(index) - } -} - -// FIXME(#12825) Indexing will always try IndexMut first and that causes issues. -/*impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> ops::IndexMut<K, V> for HashMap<K, V, H> { - #[inline] - fn index_mut<'a>(&'a mut self, index: &K) -> &'a mut V { - self.get_mut(index) - } -}*/ - -/// HashMap iterator -pub type Entries<'a, K, V> = table::Entries<'a, K, V>; - -/// HashMap mutable values iterator -pub type MutEntries<'a, K, V> = table::MutEntries<'a, K, V>; - -/// HashMap move iterator -pub type MoveEntries<K, V> = - iter::Map<'static, (table::SafeHash, K, V), (K, V), table::MoveEntries<K, V>>; - -/// HashMap keys iterator -pub type Keys<'a, K, V> = - iter::Map<'static, (&'a K, &'a V), &'a K, Entries<'a, K, V>>; - -/// HashMap values iterator -pub type Values<'a, K, V> = - iter::Map<'static, (&'a K, &'a V), &'a V, Entries<'a, K, V>>; - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> FromIterator<(K, V)> for HashMap<K, V, H> { - fn from_iter<T: Iterator<(K, V)>>(iter: T) -> HashMap<K, V, H> { - let (lower, _) = iter.size_hint(); - let mut map = HashMap::with_capacity_and_hasher(lower, Default::default()); - map.extend(iter); - map - } -} - -impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> Extendable<(K, V)> for HashMap<K, V, H> { - fn extend<T: Iterator<(K, V)>>(&mut self, mut iter: T) { - for (k, v) in iter { - self.insert(k, v); - } - } -} - -/// HashSet iterator -pub type SetItems<'a, K> = - iter::Map<'static, (&'a K, &'a ()), &'a K, Entries<'a, K, ()>>; - -/// HashSet move iterator -pub type SetMoveItems<K> = - iter::Map<'static, (K, ()), K, MoveEntries<K, ()>>; - -/// An implementation of a hash set using the underlying representation of a -/// HashMap where the value is (). As with the `HashMap` type, a `HashSet` -/// requires that the elements implement the `Eq` and `Hash` traits. -/// -/// # Example -/// -/// ``` -/// use std::collections::HashSet; -/// -/// // Type inference lets us omit an explicit type signature (which -/// // would be `HashSet<&str>` in this example). -/// let mut books = HashSet::new(); -/// -/// // Add some books. -/// books.insert("A Dance With Dragons"); -/// books.insert("To Kill a Mockingbird"); -/// books.insert("The Odyssey"); -/// books.insert("The Great Gatsby"); -/// -/// // 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.iter() { -/// 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`. -/// -/// ```rust -/// use std::collections::HashSet; -/// -/// #[deriving(Hash, Eq, PartialEq, Show)] -/// struct Viking<'a> { -/// name: &'a str, -/// power: uint, -/// } -/// -/// let mut vikings = HashSet::new(); -/// -/// vikings.insert(Viking { name: "Einar", power: 9u }); -/// vikings.insert(Viking { name: "Einar", power: 9u }); -/// vikings.insert(Viking { name: "Olaf", power: 4u }); -/// vikings.insert(Viking { name: "Harald", power: 8u }); -/// -/// // Use derived implementation to print the vikings. -/// for x in vikings.iter() { -/// println!("{}", x); -/// } -/// ``` -#[deriving(Clone)] -pub struct HashSet<T, H = RandomSipHasher> { - map: HashMap<T, (), H> -} - -impl<T: Hash + Eq> HashSet<T, RandomSipHasher> { - /// Create an empty HashSet. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashSet; - /// let mut set: HashSet<int> = HashSet::new(); - /// ``` - #[inline] - pub fn new() -> HashSet<T, RandomSipHasher> { - HashSet::with_capacity(INITIAL_CAPACITY) - } - - /// Create an empty HashSet with space for at least `n` elements in - /// the hash table. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashSet; - /// let mut set: HashSet<int> = HashSet::with_capacity(10); - /// ``` - #[inline] - pub fn with_capacity(capacity: uint) -> HashSet<T, RandomSipHasher> { - HashSet { map: HashMap::with_capacity(capacity) } - } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S>> HashSet<T, H> { - /// 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. - /// - /// # Example - /// - /// ```rust - /// use std::collections::HashSet; - /// use std::hash::sip::SipHasher; - /// - /// let h = SipHasher::new(); - /// let mut set = HashSet::with_hasher(h); - /// set.insert(2u); - /// ``` - #[inline] - pub fn with_hasher(hasher: H) -> HashSet<T, H> { - HashSet::with_capacity_and_hasher(INITIAL_CAPACITY, hasher) - } - - /// Create an empty HashSet with space for at least `capacity` - /// elements in the hash table, using `hasher` to hash the keys. - /// - /// 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. - /// - /// # Example - /// - /// ```rust - /// use std::collections::HashSet; - /// use std::hash::sip::SipHasher; - /// - /// let h = SipHasher::new(); - /// let mut set = HashSet::with_capacity_and_hasher(10u, h); - /// set.insert(1i); - /// ``` - #[inline] - pub fn with_capacity_and_hasher(capacity: uint, hasher: H) -> HashSet<T, H> { - HashSet { map: HashMap::with_capacity_and_hasher(capacity, hasher) } - } - - /// Reserve space for at least `n` elements in the hash table. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashSet; - /// let mut set: HashSet<int> = HashSet::new(); - /// set.reserve(10); - /// ``` - pub fn reserve(&mut self, n: uint) { - self.map.reserve(n) - } - - /// Returns true if the hash set contains a value equivalent to the - /// given query value. - /// - /// # Example - /// - /// This is a slightly silly example where we define the number's - /// parity as the equivalence class. It is important that the - /// values hash the same, which is why we implement `Hash`. - /// - /// ```rust - /// use std::collections::HashSet; - /// use std::hash::Hash; - /// use std::hash::sip::SipState; - /// - /// #[deriving(Eq, PartialEq)] - /// struct EvenOrOdd { - /// num: uint - /// }; - /// - /// impl Hash for EvenOrOdd { - /// fn hash(&self, state: &mut SipState) { - /// let parity = self.num % 2; - /// parity.hash(state); - /// } - /// } - /// - /// impl Equiv<EvenOrOdd> for EvenOrOdd { - /// fn equiv(&self, other: &EvenOrOdd) -> bool { - /// self.num % 2 == other.num % 2 - /// } - /// } - /// - /// let mut set = HashSet::new(); - /// set.insert(EvenOrOdd { num: 3u }); - /// - /// assert!(set.contains_equiv(&EvenOrOdd { num: 3u })); - /// assert!(set.contains_equiv(&EvenOrOdd { num: 5u })); - /// assert!(!set.contains_equiv(&EvenOrOdd { num: 4u })); - /// assert!(!set.contains_equiv(&EvenOrOdd { num: 2u })); - /// - /// ``` - pub fn contains_equiv<Q: Hash<S> + Equiv<T>>(&self, value: &Q) -> bool { - self.map.contains_key_equiv(value) - } - - /// An iterator visiting all elements in arbitrary order. - /// Iterator element type is &'a T. - /// - /// # Example - /// - /// ``` - /// 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); - /// } - /// ``` - pub fn iter<'a>(&'a self) -> SetItems<'a, T> { - self.map.keys() - } - - /// 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. - /// - /// # Example - /// - /// ``` - /// 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.move_iter().collect(); - /// - /// // Will print in an arbitrary order. - /// for x in v.iter() { - /// println!("{}", x); - /// } - /// ``` - pub fn move_iter(self) -> SetMoveItems<T> { - self.map.move_iter().map(|(k, _)| k) - } - - /// Visit the values representing the difference. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); - /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); - /// - /// // Can be seen as `a - b`. - /// for x in a.difference(&b) { - /// println!("{}", x); // Print 1 - /// } - /// - /// let diff: HashSet<int> = a.difference(&b).map(|&x| x).collect(); - /// assert_eq!(diff, [1i].iter().map(|&x| x).collect()); - /// - /// // Note that difference is not symmetric, - /// // and `b - a` means something else: - /// let diff: HashSet<int> = b.difference(&a).map(|&x| x).collect(); - /// assert_eq!(diff, [4i].iter().map(|&x| x).collect()); - /// ``` - pub fn difference<'a>(&'a self, other: &'a HashSet<T, H>) -> SetAlgebraItems<'a, T, H> { - Repeat::new(other).zip(self.iter()) - .filter_map(|(other, elt)| { - if !other.contains(elt) { Some(elt) } else { None } - }) - } - - /// Visit the values representing the symmetric difference. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); - /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); - /// - /// // Print 1, 4 in arbitrary order. - /// for x in a.symmetric_difference(&b) { - /// println!("{}", x); - /// } - /// - /// let diff1: HashSet<int> = a.symmetric_difference(&b).map(|&x| x).collect(); - /// let diff2: HashSet<int> = b.symmetric_difference(&a).map(|&x| x).collect(); - /// - /// assert_eq!(diff1, diff2); - /// assert_eq!(diff1, [1i, 4].iter().map(|&x| x).collect()); - /// ``` - pub fn symmetric_difference<'a>(&'a self, other: &'a HashSet<T, H>) - -> Chain<SetAlgebraItems<'a, T, H>, SetAlgebraItems<'a, T, H>> { - self.difference(other).chain(other.difference(self)) - } - - /// Visit the values representing the intersection. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); - /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); - /// - /// // Print 2, 3 in arbitrary order. - /// for x in a.intersection(&b) { - /// println!("{}", x); - /// } - /// - /// let diff: HashSet<int> = a.intersection(&b).map(|&x| x).collect(); - /// assert_eq!(diff, [2i, 3].iter().map(|&x| x).collect()); - /// ``` - pub fn intersection<'a>(&'a self, other: &'a HashSet<T, H>) - -> SetAlgebraItems<'a, T, H> { - Repeat::new(other).zip(self.iter()) - .filter_map(|(other, elt)| { - if other.contains(elt) { Some(elt) } else { None } - }) - } - - /// Visit the values representing the union. - /// - /// # Example - /// - /// ``` - /// use std::collections::HashSet; - /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); - /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); - /// - /// // Print 1, 2, 3, 4 in arbitrary order. - /// for x in a.union(&b) { - /// println!("{}", x); - /// } - /// - /// let diff: HashSet<int> = a.union(&b).map(|&x| x).collect(); - /// assert_eq!(diff, [1i, 2, 3, 4].iter().map(|&x| x).collect()); - /// ``` - pub fn union<'a>(&'a self, other: &'a HashSet<T, H>) - -> Chain<SetItems<'a, T>, SetAlgebraItems<'a, T, H>> { - self.iter().chain(other.difference(self)) - } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S>> PartialEq for HashSet<T, H> { - fn eq(&self, other: &HashSet<T, H>) -> bool { - if self.len() != other.len() { return false; } - - self.iter().all(|key| other.contains(key)) - } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S>> Eq for HashSet<T, H> {} - -impl<T: Eq + Hash<S>, S, H: Hasher<S>> Collection for HashSet<T, H> { - fn len(&self) -> uint { self.map.len() } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S>> Mutable for HashSet<T, H> { - fn clear(&mut self) { self.map.clear() } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S>> Set<T> for HashSet<T, H> { - fn contains(&self, value: &T) -> bool { self.map.contains_key(value) } - - fn is_disjoint(&self, other: &HashSet<T, H>) -> bool { - self.iter().all(|v| !other.contains(v)) - } - - fn is_subset(&self, other: &HashSet<T, H>) -> bool { - self.iter().all(|v| other.contains(v)) - } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S>> MutableSet<T> for HashSet<T, H> { - fn insert(&mut self, value: T) -> bool { self.map.insert(value, ()) } - - fn remove(&mut self, value: &T) -> bool { self.map.remove(value) } -} - - -impl<T: Eq + Hash<S> + fmt::Show, S, H: Hasher<S>> fmt::Show for HashSet<T, H> { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - try!(write!(f, "{{")); - - for (i, x) in self.iter().enumerate() { - if i != 0 { try!(write!(f, ", ")); } - try!(write!(f, "{}", *x)); - } - - write!(f, "}}") - } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S> + Default> FromIterator<T> for HashSet<T, H> { - fn from_iter<I: Iterator<T>>(iter: I) -> HashSet<T, H> { - let (lower, _) = iter.size_hint(); - let mut set = HashSet::with_capacity_and_hasher(lower, Default::default()); - set.extend(iter); - set - } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S> + Default> Extendable<T> for HashSet<T, H> { - fn extend<I: Iterator<T>>(&mut self, mut iter: I) { - for k in iter { - self.insert(k); - } - } -} - -impl<T: Eq + Hash<S>, S, H: Hasher<S> + Default> Default for HashSet<T, H> { - fn default() -> HashSet<T, H> { - HashSet::with_hasher(Default::default()) - } -} - -// `Repeat` is used to feed the filter closure an explicit capture -// of a reference to the other set -/// Set operations iterator -pub type SetAlgebraItems<'a, T, H> = - FilterMap<'static, (&'a HashSet<T, H>, &'a T), &'a T, - Zip<Repeat<&'a HashSet<T, H>>, SetItems<'a, T>>>; - -#[cfg(test)] -mod test_map { - use prelude::*; - - use super::HashMap; - use cmp::Equiv; - use hash; - use iter::{Iterator,range_inclusive,range_step_inclusive}; - use cell::RefCell; - - struct KindaIntLike(int); - - impl Equiv<int> for KindaIntLike { - fn equiv(&self, other: &int) -> bool { - let KindaIntLike(this) = *self; - this == *other - } - } - impl<S: hash::Writer> hash::Hash<S> for KindaIntLike { - fn hash(&self, state: &mut S) { - let KindaIntLike(this) = *self; - this.hash(state) - } - } - - #[test] - fn test_create_capacity_zero() { - let mut m = HashMap::with_capacity(0); - - assert!(m.insert(1i, 1i)); - - 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(1i, 2i)); - assert_eq!(m.len(), 1); - assert!(m.insert(2i, 4i)); - assert_eq!(m.len(), 2); - assert_eq!(*m.find(&1).unwrap(), 2); - assert_eq!(*m.find(&2).unwrap(), 4); - } - - local_data_key!(drop_vector: RefCell<Vec<int>>) - - #[deriving(Hash, PartialEq, Eq)] - struct Dropable { - k: uint - } - - - impl Dropable { - fn new(k: uint) -> Dropable { - let v = drop_vector.get().unwrap(); - v.borrow_mut().as_mut_slice()[k] += 1; - - Dropable { k: k } - } - } - - impl Drop for Dropable { - fn drop(&mut self) { - let v = drop_vector.get().unwrap(); - v.borrow_mut().as_mut_slice()[self.k] -= 1; - } - } - - #[test] - fn test_drops() { - drop_vector.replace(Some(RefCell::new(Vec::from_elem(200, 0i)))); - - { - let mut m = HashMap::new(); - - let v = drop_vector.get().unwrap(); - for i in range(0u, 200) { - assert_eq!(v.borrow().as_slice()[i], 0); - } - drop(v); - - for i in range(0u, 100) { - let d1 = Dropable::new(i); - let d2 = Dropable::new(i+100); - m.insert(d1, d2); - } - - let v = drop_vector.get().unwrap(); - for i in range(0u, 200) { - assert_eq!(v.borrow().as_slice()[i], 1); - } - drop(v); - - for i in range(0u, 50) { - let k = Dropable::new(i); - let v = m.pop(&k); - - assert!(v.is_some()); - - let v = drop_vector.get().unwrap(); - assert_eq!(v.borrow().as_slice()[i], 1); - assert_eq!(v.borrow().as_slice()[i+100], 1); - } - - let v = drop_vector.get().unwrap(); - for i in range(0u, 50) { - assert_eq!(v.borrow().as_slice()[i], 0); - assert_eq!(v.borrow().as_slice()[i+100], 0); - } - - for i in range(50u, 100) { - assert_eq!(v.borrow().as_slice()[i], 1); - assert_eq!(v.borrow().as_slice()[i+100], 1); - } - } - - let v = drop_vector.get().unwrap(); - for i in range(0u, 200) { - assert_eq!(v.borrow().as_slice()[i], 0); - } - } - - #[test] - fn test_empty_pop() { - let mut m: HashMap<int, bool> = HashMap::new(); - assert_eq!(m.pop(&0), 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 range(0i, 10) { - assert!(m.is_empty()); - - for i in range_inclusive(1i, 1000) { - assert!(m.insert(i, i)); - - for j in range_inclusive(1, i) { - let r = m.find(&j); - assert_eq!(r, Some(&j)); - } - - for j in range_inclusive(i+1, 1000) { - let r = m.find(&j); - assert_eq!(r, None); - } - } - - for i in range_inclusive(1001i, 2000) { - assert!(!m.contains_key(&i)); - } - - // remove forwards - for i in range_inclusive(1i, 1000) { - assert!(m.remove(&i)); - - for j in range_inclusive(1, i) { - assert!(!m.contains_key(&j)); - } - - for j in range_inclusive(i+1, 1000) { - assert!(m.contains_key(&j)); - } - } - - for i in range_inclusive(1i, 1000) { - assert!(!m.contains_key(&i)); - } - - for i in range_inclusive(1i, 1000) { - assert!(m.insert(i, i)); - } - - // remove backwards - for i in range_step_inclusive(1000i, 1, -1) { - assert!(m.remove(&i)); - - for j in range_inclusive(i, 1000) { - assert!(!m.contains_key(&j)); - } - - for j in range_inclusive(1, i-1) { - assert!(m.contains_key(&j)); - } - } - } - } - - #[test] - fn test_find_mut() { - let mut m = HashMap::new(); - assert!(m.insert(1i, 12i)); - assert!(m.insert(2i, 8i)); - assert!(m.insert(5i, 14i)); - let new = 100; - match m.find_mut(&5) { - None => fail!(), Some(x) => *x = new - } - assert_eq!(m.find(&5), Some(&new)); - } - - #[test] - fn test_insert_overwrite() { - let mut m = HashMap::new(); - assert!(m.insert(1i, 2i)); - assert_eq!(*m.find(&1).unwrap(), 2); - assert!(!m.insert(1i, 3i)); - assert_eq!(*m.find(&1).unwrap(), 3); - } - - #[test] - fn test_insert_conflicts() { - let mut m = HashMap::with_capacity(4); - assert!(m.insert(1i, 2i)); - assert!(m.insert(5i, 3i)); - assert!(m.insert(9i, 4i)); - assert_eq!(*m.find(&9).unwrap(), 4); - assert_eq!(*m.find(&5).unwrap(), 3); - assert_eq!(*m.find(&1).unwrap(), 2); - } - - #[test] - fn test_conflict_remove() { - let mut m = HashMap::with_capacity(4); - assert!(m.insert(1i, 2i)); - assert_eq!(*m.find(&1).unwrap(), 2); - assert!(m.insert(5, 3)); - assert_eq!(*m.find(&1).unwrap(), 2); - assert_eq!(*m.find(&5).unwrap(), 3); - assert!(m.insert(9, 4)); - assert_eq!(*m.find(&1).unwrap(), 2); - assert_eq!(*m.find(&5).unwrap(), 3); - assert_eq!(*m.find(&9).unwrap(), 4); - assert!(m.remove(&1)); - assert_eq!(*m.find(&9).unwrap(), 4); - assert_eq!(*m.find(&5).unwrap(), 3); - } - - #[test] - fn test_is_empty() { - let mut m = HashMap::with_capacity(4); - assert!(m.insert(1i, 2i)); - assert!(!m.is_empty()); - assert!(m.remove(&1)); - assert!(m.is_empty()); - } - - #[test] - fn test_pop() { - let mut m = HashMap::new(); - m.insert(1i, 2i); - assert_eq!(m.pop(&1), Some(2)); - assert_eq!(m.pop(&1), None); - } - - #[test] - #[allow(experimental)] - fn test_pop_equiv() { - let mut m = HashMap::new(); - m.insert(1i, 2i); - assert_eq!(m.pop_equiv(&KindaIntLike(1)), Some(2)); - assert_eq!(m.pop_equiv(&KindaIntLike(1)), None); - } - - #[test] - fn test_swap() { - let mut m = HashMap::new(); - assert_eq!(m.swap(1i, 2i), None); - assert_eq!(m.swap(1i, 3i), Some(2)); - assert_eq!(m.swap(1i, 4i), Some(3)); - } - - #[test] - fn test_move_iter() { - let hm = { - let mut hm = HashMap::new(); - - hm.insert('a', 1i); - hm.insert('b', 2i); - - hm - }; - - let v = hm.move_iter().collect::<Vec<(char, int)>>(); - assert!([('a', 1), ('b', 2)] == v.as_slice() || [('b', 2), ('a', 1)] == v.as_slice()); - } - - #[test] - fn test_iterate() { - let mut m = HashMap::with_capacity(4); - for i in range(0u, 32) { - assert!(m.insert(i, i*2)); - } - assert_eq!(m.len(), 32); - - let mut observed: u32 = 0; - - for (k, v) in m.iter() { - assert_eq!(*v, *k * 2); - observed |= 1 << *k; - } - assert_eq!(observed, 0xFFFF_FFFF); - } - - #[test] - fn test_keys() { - let vec = vec![(1i, 'a'), (2i, 'b'), (3i, 'c')]; - let map = vec.move_iter().collect::<HashMap<int, char>>(); - let keys = map.keys().map(|&k| k).collect::<Vec<int>>(); - assert_eq!(keys.len(), 3); - assert!(keys.contains(&1)); - assert!(keys.contains(&2)); - assert!(keys.contains(&3)); - } - - #[test] - fn test_values() { - let vec = vec![(1i, 'a'), (2i, 'b'), (3i, 'c')]; - let map = vec.move_iter().collect::<HashMap<int, char>>(); - let values = map.values().map(|&v| v).collect::<Vec<char>>(); - assert_eq!(values.len(), 3); - assert!(values.contains(&'a')); - assert!(values.contains(&'b')); - assert!(values.contains(&'c')); - } - - #[test] - fn test_find() { - let mut m = HashMap::new(); - assert!(m.find(&1i).is_none()); - m.insert(1i, 2i); - match m.find(&1) { - None => fail!(), - Some(v) => assert_eq!(*v, 2) - } - } - - #[test] - fn test_eq() { - let mut m1 = HashMap::new(); - m1.insert(1i, 2i); - m1.insert(2i, 3i); - m1.insert(3i, 4i); - - let mut m2 = HashMap::new(); - m2.insert(1i, 2i); - m2.insert(2i, 3i); - - assert!(m1 != m2); - - m2.insert(3i, 4i); - - assert_eq!(m1, m2); - } - - #[test] - fn test_show() { - let mut map: HashMap<int, int> = HashMap::new(); - let empty: HashMap<int, int> = HashMap::new(); - - map.insert(1i, 2i); - map.insert(3i, 4i); - - let map_str = format!("{}", map); - - assert!(map_str == "{1: 2, 3: 4}".to_string() || map_str == "{3: 4, 1: 2}".to_string()); - assert_eq!(format!("{}", empty), "{}".to_string()); - } - - #[test] - fn test_expand() { - let mut m = HashMap::new(); - - assert_eq!(m.len(), 0); - assert!(m.is_empty()); - - let mut i = 0u; - let old_cap = m.table.capacity(); - while old_cap == m.table.capacity() { - m.insert(i, i); - i += 1; - } - - assert_eq!(m.len(), i); - assert!(!m.is_empty()); - } - - #[test] - fn test_resize_policy() { - let mut m = HashMap::new(); - - assert_eq!(m.len(), 0); - assert!(m.is_empty()); - - let initial_cap = m.table.capacity(); - m.reserve(initial_cap * 2); - let cap = m.table.capacity(); - - assert_eq!(cap, initial_cap * 2); - - let mut i = 0u; - for _ in range(0, cap * 3 / 4) { - m.insert(i, i); - i += 1; - } - - assert_eq!(m.len(), i); - assert_eq!(m.table.capacity(), cap); - - for _ in range(0, cap / 4) { - m.insert(i, i); - i += 1; - } - - let new_cap = m.table.capacity(); - assert_eq!(new_cap, cap * 2); - - for _ in range(0, cap / 2) { - i -= 1; - m.remove(&i); - assert_eq!(m.table.capacity(), new_cap); - } - - for _ in range(0, cap / 2 - 1) { - i -= 1; - m.remove(&i); - } - - assert_eq!(m.table.capacity(), cap); - assert_eq!(m.len(), i); - assert!(!m.is_empty()); - } - - #[test] - fn test_find_equiv() { - let mut m = HashMap::new(); - - let (foo, bar, baz) = (1i,2i,3i); - m.insert("foo".to_string(), foo); - m.insert("bar".to_string(), bar); - m.insert("baz".to_string(), baz); - - - assert_eq!(m.find_equiv(&("foo")), Some(&foo)); - assert_eq!(m.find_equiv(&("bar")), Some(&bar)); - assert_eq!(m.find_equiv(&("baz")), Some(&baz)); - - assert_eq!(m.find_equiv(&("qux")), None); - } - - #[test] - fn test_from_iter() { - let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let map: HashMap<int, int> = xs.iter().map(|&x| x).collect(); - - for &(k, v) in xs.iter() { - assert_eq!(map.find(&k), Some(&v)); - } - } - - #[test] - fn test_size_hint() { - let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let map: HashMap<int, int> = xs.iter().map(|&x| x).collect(); - - let mut iter = map.iter(); - - for _ in iter.by_ref().take(3) {} - - assert_eq!(iter.size_hint(), (3, Some(3))); - } - - #[test] - fn test_mut_size_hint() { - let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; - - let mut map: HashMap<int, int> = xs.iter().map(|&x| x).collect(); - - let mut iter = map.mut_iter(); - - for _ in iter.by_ref().take(3) {} - - assert_eq!(iter.size_hint(), (3, Some(3))); - } - - #[test] - fn test_index() { - let mut map: HashMap<int, int> = HashMap::new(); - - map.insert(1, 2); - map.insert(2, 1); - map.insert(3, 4); - - assert_eq!(map[2], 1); - } - - #[test] - #[should_fail] - fn test_index_nonexistent() { - let mut map: HashMap<int, int> = HashMap::new(); - - map.insert(1, 2); - map.insert(2, 1); - map.insert(3, 4); - - map[4]; - } -} - -#[cfg(test)] -mod test_set { - use prelude::*; - - use super::HashSet; - use slice::ImmutablePartialEqSlice; - use collections::Collection; - - #[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(5i)); - assert!(ys.insert(11i)); - 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(0i)); - assert!(a.insert(5)); - assert!(a.insert(11)); - assert!(a.insert(7)); - - let mut b = HashSet::new(); - assert!(b.insert(0i)); - 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 range(0u, 32) { - assert!(a.insert(i)); - } - let mut observed: u32 = 0; - for k in a.iter() { - 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(11i)); - 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(2i)); - 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(1i)); - assert!(a.insert(3)); - assert!(a.insert(5)); - assert!(a.insert(9)); - assert!(a.insert(11)); - - assert!(b.insert(3i)); - 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(1i)); - assert!(a.insert(3)); - assert!(a.insert(5)); - assert!(a.insert(9)); - assert!(a.insert(11)); - - assert!(b.insert(-2i)); - 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(1i)); - 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(-2i)); - 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 = [1i, 2, 3, 4, 5, 6, 7, 8, 9]; - - let set: HashSet<int> = xs.iter().map(|&x| x).collect(); - - for x in xs.iter() { - 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.move_iter().collect::<Vec<char>>(); - assert!(['a', 'b'] == v.as_slice() || ['b', 'a'] == v.as_slice()); - } - - #[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(1i); - s1.insert(2); - s1.insert(3); - - let mut s2 = HashSet::new(); - - s2.insert(1i); - s2.insert(2); - - assert!(s1 != s2); - - s2.insert(3); - - assert_eq!(s1, s2); - } - - #[test] - fn test_show() { - let mut set: HashSet<int> = HashSet::new(); - let empty: HashSet<int> = HashSet::new(); - - set.insert(1i); - set.insert(2); - - let set_str = format!("{}", set); - - assert!(set_str == "{1, 2}".to_string() || set_str == "{2, 1}".to_string()); - assert_eq!(format!("{}", empty), "{}".to_string()); - } -} - -#[cfg(test)] -mod bench { - extern crate test; - use prelude::*; - - use self::test::Bencher; - use iter::{range_inclusive}; - - #[bench] - fn new_drop(b : &mut Bencher) { - use super::HashMap; - - b.iter(|| { - let m : HashMap<int, int> = HashMap::new(); - assert_eq!(m.len(), 0); - }) - } - - #[bench] - fn new_insert_drop(b : &mut Bencher) { - use super::HashMap; - - b.iter(|| { - let mut m = HashMap::new(); - m.insert(0i, 0i); - assert_eq!(m.len(), 1); - }) - } - - #[bench] - fn insert(b: &mut Bencher) { - use super::HashMap; - - let mut m = HashMap::new(); - - for i in range_inclusive(1i, 1000) { - 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::HashMap; - - let mut m = HashMap::new(); - - for i in range_inclusive(1i, 1000) { - m.insert(i, i); - } - - b.iter(|| { - for i in range_inclusive(1i, 1000) { - m.contains_key(&i); - } - }); - } - - #[bench] - fn find_nonexisting(b: &mut Bencher) { - use super::HashMap; - - let mut m = HashMap::new(); - - for i in range_inclusive(1i, 1000) { - m.insert(i, i); - } - - b.iter(|| { - for i in range_inclusive(1001i, 2000) { - m.contains_key(&i); - } - }); - } - - #[bench] - fn hashmap_as_queue(b: &mut Bencher) { - use super::HashMap; - - let mut m = HashMap::new(); - - for i in range_inclusive(1i, 1000) { - m.insert(i, i); - } - - let mut k = 1i; - - b.iter(|| { - m.pop(&k); - m.insert(k + 1000, k + 1000); - k += 1; - }); - } - - #[bench] - fn find_pop_insert(b: &mut Bencher) { - use super::HashMap; - - let mut m = HashMap::new(); - - for i in range_inclusive(1i, 1000) { - m.insert(i, i); - } - - let mut k = 1i; - - b.iter(|| { - m.find(&(k + 400)); - m.find(&(k + 2000)); - m.pop(&k); - m.insert(k + 1000, k + 1000); - k += 1; - }) - } -} diff --git a/src/libstd/collections/hashmap/bench.rs b/src/libstd/collections/hashmap/bench.rs new file mode 100644 index 00000000000..21bbb38f489 --- /dev/null +++ b/src/libstd/collections/hashmap/bench.rs @@ -0,0 +1,130 @@ +// 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 prelude::*; + +use self::test::Bencher; +use iter::{range_inclusive}; + +#[bench] +fn new_drop(b : &mut Bencher) { + use super::HashMap; + + b.iter(|| { + let m : HashMap<int, int> = HashMap::new(); + assert_eq!(m.len(), 0); + }) +} + +#[bench] +fn new_insert_drop(b : &mut Bencher) { + use super::HashMap; + + b.iter(|| { + let mut m = HashMap::new(); + m.insert(0i, 0i); + assert_eq!(m.len(), 1); + }) +} + +#[bench] +fn grow_by_insertion(b: &mut Bencher) { + use super::HashMap; + + let mut m = HashMap::new(); + + for i in range_inclusive(1i, 1000) { + 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::HashMap; + + let mut m = HashMap::new(); + + for i in range_inclusive(1i, 1000) { + m.insert(i, i); + } + + b.iter(|| { + for i in range_inclusive(1i, 1000) { + m.contains_key(&i); + } + }); +} + +#[bench] +fn find_nonexisting(b: &mut Bencher) { + use super::HashMap; + + let mut m = HashMap::new(); + + for i in range_inclusive(1i, 1000) { + m.insert(i, i); + } + + b.iter(|| { + for i in range_inclusive(1001i, 2000) { + m.contains_key(&i); + } + }); +} + +#[bench] +fn hashmap_as_queue(b: &mut Bencher) { + use super::HashMap; + + let mut m = HashMap::new(); + + for i in range_inclusive(1i, 1000) { + m.insert(i, i); + } + + let mut k = 1i; + + b.iter(|| { + m.pop(&k); + m.insert(k + 1000, k + 1000); + k += 1; + }); +} + +#[bench] +fn find_pop_insert(b: &mut Bencher) { + use super::HashMap; + + let mut m = HashMap::new(); + + for i in range_inclusive(1i, 1000) { + m.insert(i, i); + } + + let mut k = 1i; + + b.iter(|| { + m.find(&(k + 400)); + m.find(&(k + 2000)); + m.pop(&k); + m.insert(k + 1000, k + 1000); + k += 1; + }) +} diff --git a/src/libstd/collections/hashmap/map.rs b/src/libstd/collections/hashmap/map.rs new file mode 100644 index 00000000000..a50c6a59f7e --- /dev/null +++ b/src/libstd/collections/hashmap/map.rs @@ -0,0 +1,2017 @@ +// 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. +// +// ignore-lexer-test FIXME #15883 + +use clone::Clone; +use cmp::{max, Eq, Equiv, PartialEq}; +use collections::{Collection, Mutable, MutableSet, Map, MutableMap}; +use default::Default; +use fmt::Show; +use fmt; +use hash::{Hash, Hasher, RandomSipHasher}; +use iter::{Iterator, FromIterator, Extendable}; +use iter; +use mem::replace; +use num; +use ops::{Deref, DerefMut}; +use option::{Some, None, Option}; +use result::{Ok, Err}; +use ops::Index; + +use super::table; +use super::table::{ + Bucket, + Empty, + Full, + FullBucket, + FullBucketImm, + FullBucketMut, + RawTable, + SafeHash +}; + +static INITIAL_LOG2_CAP: uint = 5; +pub static INITIAL_CAPACITY: uint = 1 << INITIAL_LOG2_CAP; // 2^5 + +/// The default behavior of HashMap implements a load factor of 90.9%. +/// This behavior is characterized by the following conditions: +/// +/// - if size > 0.909 * capacity: grow +/// - if size < 0.25 * capacity: shrink (if this won't bring capacity lower +/// than the minimum) +#[deriving(Clone)] +struct DefaultResizePolicy { + /// Doubled minimal capacity. The capacity must never drop below + /// the minimum capacity. (The check happens before the capacity + /// is potentially halved.) + minimum_capacity2: uint +} + +impl DefaultResizePolicy { + fn new(new_capacity: uint) -> DefaultResizePolicy { + DefaultResizePolicy { + minimum_capacity2: new_capacity << 1 + } + } + + #[inline] + fn capacity_range(&self, new_size: uint) -> (uint, uint) { + // Here, we are rephrasing the logic by specifying the ranges: + // + // - if `size * 1.1 < cap < size * 4`: don't resize + // - if `cap < minimum_capacity * 2`: don't shrink + // - otherwise, resize accordingly + ((new_size * 11) / 10, max(new_size << 2, self.minimum_capacity2)) + } + + #[inline] + fn reserve(&mut self, new_capacity: uint) { + self.minimum_capacity2 = new_capacity << 1; + } +} + +// 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_generic` 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. Intutively, +// 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 doc.rs + +/// A hash map implementation which uses linear probing with Robin +/// Hood bucket stealing. +/// +/// The hashes are all keyed by the task-local random number generator +/// on creation by default. This means that the ordering of the keys is +/// randomized, but makes the tables more resistant to +/// denial-of-service attacks (Hash DoS). This behaviour can be +/// overridden with one of the constructors. +/// +/// It is required that the keys implement the `Eq` and `Hash` traits, although +/// this can frequently be achieved by using `#[deriving(Eq, Hash)]`. +/// +/// 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/) +/// +/// # Example +/// +/// ``` +/// use std::collections::HashMap; +/// +/// // type inference lets us omit an explicit type signature (which +/// // would be `HashMap<&str, &str>` in this example). +/// let mut book_reviews = HashMap::new(); +/// +/// // review some books. +/// book_reviews.insert("Adventures of Huckleberry Finn", "My favorite book."); +/// book_reviews.insert("Grimms' Fairy Tales", "Masterpiece."); +/// book_reviews.insert("Pride and Prejudice", "Very enjoyable."); +/// book_reviews.insert("The Adventures of Sherlock Holmes", "Eye lyked it alot."); +/// +/// // check for a specific one. +/// 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.iter() { +/// match book_reviews.find(book) { +/// Some(review) => println!("{}: {}", *book, *review), +/// None => println!("{} is unreviewed.", *book) +/// } +/// } +/// +/// // iterate over everything. +/// for (book, review) in book_reviews.iter() { +/// println!("{}: \"{}\"", *book, *review); +/// } +/// ``` +/// +/// The easiest way to use `HashMap` with a custom type is to derive `Eq` and `Hash`. +/// We must also derive `PartialEq`. +/// +/// ``` +/// use std::collections::HashMap; +/// +/// #[deriving(Hash, Eq, PartialEq, Show)] +/// struct Viking<'a> { +/// name: &'a str, +/// power: uint, +/// } +/// +/// let mut vikings = HashMap::new(); +/// +/// vikings.insert("Norway", Viking { name: "Einar", power: 9u }); +/// vikings.insert("Denmark", Viking { name: "Olaf", power: 4u }); +/// vikings.insert("Iceland", Viking { name: "Harald", power: 8u }); +/// +/// // Use derived implementation to print the vikings. +/// for (land, viking) in vikings.iter() { +/// println!("{} at {}", viking, land); +/// } +/// ``` +#[deriving(Clone)] +pub struct HashMap<K, V, H = RandomSipHasher> { + // All hashes are keyed on these values, to prevent hash collision attacks. + hasher: H, + + table: RawTable<K, V>, + + // We keep this at the end since it might as well have tail padding. + resize_policy: DefaultResizePolicy, +} + +/// Search for a pre-hashed key. +fn search_hashed_generic<K, V, M: Deref<RawTable<K, V>>>(table: M, + hash: &SafeHash, + is_match: |&K| -> bool) + -> SearchResult<K, V, M> { + let size = table.size(); + let mut probe = Bucket::new(table, hash); + let ib = probe.index(); + + while probe.index() != ib + size { + let full = match probe.peek() { + Empty(b) => return TableRef(b.into_table()), // hit an empty bucket + Full(b) => b + }; + + if full.distance() + ib < full.index() { + // We can finish the search early if we hit any bucket + // with a lower distance to initial bucket than we've probed. + return TableRef(full.into_table()); + } + + // If the hash doesn't match, it can't be this one.. + if *hash == full.hash() { + let matched = { + let (k, _) = full.read(); + is_match(k) + }; + + // If the key doesn't match, it can't be this one.. + if matched { + return FoundExisting(full); + } + } + + probe = full.next(); + } + + TableRef(probe.into_table()) +} + +fn search_hashed<K: Eq, V, M: Deref<RawTable<K, V>>>(table: M, hash: &SafeHash, k: &K) + -> SearchResult<K, V, M> { + search_hashed_generic(table, hash, |k_| *k == *k_) +} + +fn pop_internal<K, V>(starting_bucket: FullBucketMut<K, V>) -> V { + let (empty, _k, retval) = starting_bucket.take(); + let mut gap = match empty.gap_peek() { + Some(b) => b, + None => return retval + }; + + while gap.full().distance() != 0 { + gap = match gap.shift() { + Some(b) => b, + None => break + }; + } + + // Now we've done all our shifting. Return the value we grabbed earlier. + return retval; +} + +/// Perform robin hood bucket stealing at the given `bucket`. You must +/// also pass the position of that bucket's initial bucket so we don't have +/// to recalculate it. +/// +/// `hash`, `k`, and `v` are the elements to "robin hood" into the hashtable. +fn robin_hood<'a, K: 'a, V: 'a>(mut bucket: FullBucketMut<'a, K, V>, + mut ib: uint, + mut hash: SafeHash, + mut k: K, + mut v: V) + -> &'a mut V { + let starting_index = bucket.index(); + let size = { + let table = bucket.table(); // FIXME "lifetime too short". + table.size() + }; + // There can be at most `size - dib` buckets to displace, because + // in the worst case, there are `size` elements and we already are + // `distance` buckets away from the initial one. + let idx_end = starting_index + size - bucket.distance(); + + loop { + let (old_hash, old_key, old_val) = bucket.replace(hash, k, v); + loop { + let probe = bucket.next(); + assert!(probe.index() != idx_end); + + let full_bucket = match probe.peek() { + table::Empty(bucket) => { + // Found a hole! + let b = bucket.put(old_hash, old_key, old_val); + // Now that it's stolen, just read the value's pointer + // right out of the table! + let (_, v) = Bucket::at_index(b.into_table(), starting_index).peek() + .expect_full() + .into_mut_refs(); + return v; + }, + table::Full(bucket) => bucket + }; + + let probe_ib = full_bucket.index() - full_bucket.distance(); + + bucket = full_bucket; + + // Robin hood! Steal the spot. + if ib < probe_ib { + ib = probe_ib; + hash = old_hash; + k = old_key; + v = old_val; + break; + } + } + } +} + +/// A result that works like Option<FullBucket<..>> but preserves +/// the reference that grants us access to the table in any case. +enum SearchResult<K, V, M> { + // This is an entry that holds the given key: + FoundExisting(FullBucket<K, V, M>), + + // There was no such entry. The reference is given back: + TableRef(M) +} + +impl<K, V, M> SearchResult<K, V, M> { + fn into_option(self) -> Option<FullBucket<K, V, M>> { + match self { + FoundExisting(bucket) => Some(bucket), + TableRef(_) => None + } + } +} + +/// A newtyped mutable reference to the hashmap that allows e.g. Deref to be +/// implemented without making changes to the visible interface of HashMap. +/// Used internally because it's accepted by the search functions above. +struct MapMutRef<'a, K: 'a, V: 'a, H: 'a> { + map_ref: &'a mut HashMap<K, V, H> +} + +impl<'a, K, V, H> Deref<RawTable<K, V>> for MapMutRef<'a, K, V, H> { + fn deref(&self) -> &RawTable<K, V> { + &self.map_ref.table + } +} + +impl<'a, K, V, H> DerefMut<RawTable<K, V>> for MapMutRef<'a, K, V, H> { + fn deref_mut(&mut self) -> &mut RawTable<K, V> { + &mut self.map_ref.table + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> { + fn make_hash<X: Hash<S>>(&self, x: &X) -> SafeHash { + table::make_hash(&self.hasher, x) + } + + fn search_equiv<'a, Q: Hash<S> + Equiv<K>>(&'a self, q: &Q) + -> Option<FullBucketImm<'a, K, V>> { + let hash = self.make_hash(q); + search_hashed_generic(&self.table, &hash, |k| q.equiv(k)).into_option() + } + + fn search_equiv_mut<'a, Q: Hash<S> + Equiv<K>>(&'a mut self, q: &Q) + -> Option<FullBucketMut<'a, K, V>> { + let hash = self.make_hash(q); + search_hashed_generic(&mut self.table, &hash, |k| q.equiv(k)).into_option() + } + + /// 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, use + /// search_hashed. + fn search<'a>(&'a self, k: &K) -> Option<FullBucketImm<'a, K, V>> { + let hash = self.make_hash(k); + search_hashed(&self.table, &hash, k).into_option() + } + + fn search_mut<'a>(&'a mut self, k: &K) -> Option<FullBucketMut<'a, K, V>> { + let hash = self.make_hash(k); + search_hashed(&mut self.table, &hash, k).into_option() + } + + // The caller should ensure that invariants by Robin Hood Hashing hold. + fn insert_hashed_ordered(&mut self, hash: SafeHash, k: K, v: V) { + let cap = self.table.capacity(); + let mut buckets = Bucket::new(&mut self.table, &hash); + let ib = buckets.index(); + + while buckets.index() != ib + cap { + // 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(); + } + fail!("Internal HashMap error: Out of space."); + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Collection for HashMap<K, V, H> { + /// Return the number of elements in the map. + fn len(&self) -> uint { self.table.size() } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Mutable for HashMap<K, V, H> { + /// Clear the map, removing all key-value pairs. Keeps the allocated memory + /// for reuse. + fn clear(&mut self) { + // Prevent reallocations from happening from now on. Makes it possible + // for the map to be reused but has a downside: reserves permanently. + self.resize_policy.reserve(self.table.size()); + + let cap = self.table.capacity(); + let mut buckets = Bucket::first(&mut self.table); + + while buckets.index() != cap { + buckets = match buckets.peek() { + Empty(b) => b.next(), + Full(full) => { + let (b, _, _) = full.take(); + b.next() + } + }; + } + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Map<K, V> for HashMap<K, V, H> { + fn find<'a>(&'a self, k: &K) -> Option<&'a V> { + self.search(k).map(|bucket| { + let (_, v) = bucket.into_refs(); + v + }) + } + + fn contains_key(&self, k: &K) -> bool { + self.search(k).is_some() + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> MutableMap<K, V> for HashMap<K, V, H> { + fn find_mut<'a>(&'a mut self, k: &K) -> Option<&'a mut V> { + match self.search_mut(k) { + Some(bucket) => { + let (_, v) = bucket.into_mut_refs(); + Some(v) + } + _ => None + } + } + + fn swap(&mut self, k: K, v: V) -> Option<V> { + let hash = self.make_hash(&k); + let potential_new_size = self.table.size() + 1; + self.make_some_room(potential_new_size); + + let mut retval = None; + self.insert_or_replace_with(hash, k, v, |_, val_ref, val| { + retval = Some(replace(val_ref, val)); + }); + retval + } + + + fn pop(&mut self, k: &K) -> Option<V> { + if self.table.size() == 0 { + return None + } + + let potential_new_size = self.table.size() - 1; + self.make_some_room(potential_new_size); + + self.search_mut(k).map(|bucket| { + pop_internal(bucket) + }) + } +} + +impl<K: Hash + Eq, V> HashMap<K, V, RandomSipHasher> { + /// Create an empty HashMap. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map: HashMap<&str, int> = HashMap::with_capacity(10); + /// ``` + #[inline] + pub fn new() -> HashMap<K, V, RandomSipHasher> { + let hasher = RandomSipHasher::new(); + HashMap::with_hasher(hasher) + } + + /// Creates an empty hash map with the given initial capacity. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map: HashMap<&str, int> = HashMap::with_capacity(10); + /// ``` + #[inline] + pub fn with_capacity(capacity: uint) -> HashMap<K, V, RandomSipHasher> { + let hasher = RandomSipHasher::new(); + HashMap::with_capacity_and_hasher(capacity, hasher) + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> HashMap<K, V, H> { + /// Creates an empty hashmap which will use the given hasher to hash keys. + /// + /// The creates map has the default initial capacity. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// use std::hash::sip::SipHasher; + /// + /// let h = SipHasher::new(); + /// let mut map = HashMap::with_hasher(h); + /// map.insert(1i, 2u); + /// ``` + #[inline] + pub fn with_hasher(hasher: H) -> HashMap<K, V, H> { + HashMap { + hasher: hasher, + resize_policy: DefaultResizePolicy::new(INITIAL_CAPACITY), + table: RawTable::new(0), + } + } + + /// Create an empty HashMap with space for at least `capacity` + /// elements, using `hasher` to hash the keys. + /// + /// Warning: `hasher` 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. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// use std::hash::sip::SipHasher; + /// + /// let h = SipHasher::new(); + /// let mut map = HashMap::with_capacity_and_hasher(10, h); + /// map.insert(1i, 2u); + /// ``` + #[inline] + pub fn with_capacity_and_hasher(capacity: uint, hasher: H) -> HashMap<K, V, H> { + let cap = num::next_power_of_two(max(INITIAL_CAPACITY, capacity)); + HashMap { + hasher: hasher, + resize_policy: DefaultResizePolicy::new(cap), + table: RawTable::new(cap), + } + } + + /// The hashtable will never try to shrink below this size. You can use + /// this function to reduce reallocations if your hashtable frequently + /// grows and shrinks by large amounts. + /// + /// This function has no effect on the operational semantics of the + /// hashtable, only on performance. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map: HashMap<&str, int> = HashMap::new(); + /// map.reserve(10); + /// ``` + pub fn reserve(&mut self, new_minimum_capacity: uint) { + let cap = num::next_power_of_two( + max(INITIAL_CAPACITY, new_minimum_capacity)); + + self.resize_policy.reserve(cap); + + if self.table.capacity() < cap { + self.resize(cap); + } + } + + /// Resizes the internal vectors to a new capacity. It's your responsibility to: + /// 1) Make sure the new capacity is enough for all the elements, accounting + /// for the load factor. + /// 2) Ensure new_capacity is a power of two. + fn resize(&mut self, new_capacity: uint) { + assert!(self.table.size() <= new_capacity); + assert!(num::is_power_of_two(new_capacity)); + + let mut old_table = replace(&mut self.table, RawTable::new(new_capacity)); + let old_size = old_table.size(); + + if old_table.capacity() == 0 || old_table.size() == 0 { + return; + } + + if new_capacity < old_table.capacity() { + // Shrink the table. Naive algorithm for resizing: + for (h, k, v) in old_table.move_iter() { + self.insert_hashed_nocheck(h, k, v); + } + } else { + // Grow the table. + // Specialization of the other branch. + let mut bucket = Bucket::first(&mut old_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. + loop { + bucket = match bucket.peek() { + Full(full) => { + if full.distance() == 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(); + } + + // 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); + { + let t = b.table(); // FIXME "lifetime too short". + if t.size() == 0 { break } + }; + b.into_bucket() + } + Empty(b) => b.into_bucket() + }; + bucket.next(); + } + } + + assert_eq!(self.table.size(), old_size); + } + + /// Performs any necessary resize operations, such that there's space for + /// new_size elements. + fn make_some_room(&mut self, new_size: uint) { + let (grow_at, shrink_at) = self.resize_policy.capacity_range(new_size); + let cap = self.table.capacity(); + + // An invalid value shouldn't make us run out of space. + debug_assert!(grow_at >= new_size); + + if cap <= grow_at { + let new_capacity = max(cap << 1, INITIAL_CAPACITY); + self.resize(new_capacity); + } else if shrink_at <= cap { + let new_capacity = cap >> 1; + self.resize(new_capacity); + } + } + + /// 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) -> &mut V { + self.insert_or_replace_with(hash, k, v, |_, _, _| ()) + } + + fn insert_or_replace_with<'a>(&'a mut self, + hash: SafeHash, + k: K, + v: V, + found_existing: |&mut K, &mut V, V|) + -> &'a mut V { + // Worst case, we'll find one empty bucket among `size + 1` buckets. + let size = self.table.size(); + let mut probe = Bucket::new(&mut self.table, &hash); + let ib = probe.index(); + + loop { + let mut bucket = match probe.peek() { + Empty(bucket) => { + // Found a hole! + let bucket = bucket.put(hash, k, v); + let (_, val) = bucket.into_mut_refs(); + return val; + }, + Full(bucket) => bucket + }; + + if bucket.hash() == hash { + let found_match = { + let (bucket_k, _) = bucket.read_mut(); + k == *bucket_k + }; + if found_match { + let (bucket_k, bucket_v) = bucket.into_mut_refs(); + debug_assert!(k == *bucket_k); + // Key already exists. Get its reference. + found_existing(bucket_k, bucket_v, v); + return bucket_v; + } + } + + let robin_ib = bucket.index() as int - bucket.distance() as int; + + if (ib as int) < robin_ib { + // Found a luckier bucket than me. Better steal his spot. + return robin_hood(bucket, robin_ib as uint, hash, k, v); + } + + probe = bucket.next(); + assert!(probe.index() != ib + size + 1); + } + } + + /// Inserts an element which has already been hashed, returning a reference + /// to that element inside the hashtable. This is more efficient that using + /// `insert`, since the key will not be rehashed. + fn insert_hashed(&mut self, hash: SafeHash, k: K, v: V) -> &mut V { + let potential_new_size = self.table.size() + 1; + self.make_some_room(potential_new_size); + self.insert_hashed_nocheck(hash, k, v) + } + + /// Return the value corresponding to the key in the map, or insert + /// and return the value if it doesn't exist. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map = HashMap::new(); + /// + /// // Insert 1i with key "a" + /// assert_eq!(*map.find_or_insert("a", 1i), 1); + /// + /// // Find the existing key + /// assert_eq!(*map.find_or_insert("a", -2), 1); + /// ``` + pub fn find_or_insert(&mut self, k: K, v: V) -> &mut V { + self.find_with_or_insert_with(k, v, |_k, _v, _a| (), |_k, a| a) + } + + /// Return the value corresponding to the key in the map, or create, + /// insert, and return a new value if it doesn't exist. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map = HashMap::new(); + /// + /// // Insert 10 with key 2 + /// assert_eq!(*map.find_or_insert_with(2i, |&key| 5 * key as uint), 10u); + /// + /// // Find the existing key + /// assert_eq!(*map.find_or_insert_with(2, |&key| key as uint), 10); + /// ``` + pub fn find_or_insert_with<'a>(&'a mut self, k: K, f: |&K| -> V) + -> &'a mut V { + self.find_with_or_insert_with(k, (), |_k, _v, _a| (), |k, _a| f(k)) + } + + /// Insert a key-value pair into the map if the key is not already present. + /// Otherwise, modify the existing value for the key. + /// Returns the new or modified value for the key. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// let mut map = HashMap::new(); + /// + /// // Insert 2 with key "a" + /// assert_eq!(*map.insert_or_update_with("a", 2u, |_key, val| *val = 3), 2); + /// + /// // Update and return the existing value + /// assert_eq!(*map.insert_or_update_with("a", 9, |_key, val| *val = 7), 7); + /// assert_eq!(map["a"], 7); + /// ``` + pub fn insert_or_update_with<'a>( + &'a mut self, + k: K, + v: V, + f: |&K, &mut V|) + -> &'a mut V { + let potential_new_size = self.table.size() + 1; + self.make_some_room(potential_new_size); + + let hash = self.make_hash(&k); + self.insert_or_replace_with(hash, k, v, |kref, vref, _v| f(kref, vref)) + } + + /// Modify and return the value corresponding to the key in the map, or + /// insert and return a new value if it doesn't exist. + /// + /// This method allows for all insertion behaviours of a hashmap; + /// see methods like + /// [`insert`](../trait.MutableMap.html#tymethod.insert), + /// [`find_or_insert`](#method.find_or_insert) and + /// [`insert_or_update_with`](#method.insert_or_update_with) + /// for less general and more friendly variations of this. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// // map some strings to vectors of strings + /// let mut map = HashMap::new(); + /// map.insert("a key", vec!["value"]); + /// map.insert("z key", vec!["value"]); + /// + /// let new = vec!["a key", "b key", "z key"]; + /// + /// for k in new.move_iter() { + /// map.find_with_or_insert_with( + /// k, "new value", + /// // if the key does exist either prepend or append this + /// // new value based on the first letter of the key. + /// |key, already, new| { + /// if key.as_slice().starts_with("z") { + /// already.insert(0, new); + /// } else { + /// already.push(new); + /// } + /// }, + /// // if the key doesn't exist in the map yet, add it in + /// // the obvious way. + /// |_k, v| vec![v]); + /// } + /// + /// assert_eq!(map.len(), 3); + /// assert_eq!(map["a key"], vec!["value", "new value"]); + /// assert_eq!(map["b key"], vec!["new value"]); + /// assert_eq!(map["z key"], vec!["new value", "value"]); + /// ``` + pub fn find_with_or_insert_with<'a, A>(&'a mut self, + k: K, + a: A, + found: |&K, &mut V, A|, + not_found: |&K, A| -> V) + -> &'a mut V + { + let hash = self.make_hash(&k); + let this = MapMutRef { map_ref: self }; + + match search_hashed(this, &hash, &k) { + FoundExisting(bucket) => { + let (_, v_ref) = bucket.into_mut_refs(); + found(&k, v_ref, a); + v_ref + } + TableRef(this) => { + let v = not_found(&k, a); + this.map_ref.insert_hashed(hash, k, v) + } + } + } + + /// Retrieves a value for the given key. + /// See [`find`](../trait.Map.html#tymethod.find) for a non-failing alternative. + /// + /// # Failure + /// + /// Fails if the key is not present. + /// + /// # Example + /// + /// ``` + /// #![allow(deprecated)] + /// + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// map.insert("a", 1i); + /// assert_eq!(map.get(&"a"), &1); + /// ``` + #[deprecated = "prefer indexing instead, e.g., map[key]"] + pub fn get<'a>(&'a self, k: &K) -> &'a V { + match self.find(k) { + Some(v) => v, + None => fail!("no entry found for key") + } + } + + /// Retrieves a mutable value for the given key. + /// See [`find_mut`](../trait.MutableMap.html#tymethod.find_mut) for a non-failing alternative. + /// + /// # Failure + /// + /// Fails if the key is not present. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// map.insert("a", 1i); + /// { + /// // val will freeze map to prevent usage during its lifetime + /// let val = map.get_mut(&"a"); + /// *val = 40; + /// } + /// assert_eq!(map["a"], 40); + /// + /// // A more direct way could be: + /// *map.get_mut(&"a") = -2; + /// assert_eq!(map["a"], -2); + /// ``` + pub fn get_mut<'a>(&'a mut self, k: &K) -> &'a mut V { + match self.find_mut(k) { + Some(v) => v, + None => fail!("no entry found for key") + } + } + + /// Return true if the map contains a value for the specified key, + /// using equivalence. + /// + /// See [pop_equiv](#method.pop_equiv) for an extended example. + pub fn contains_key_equiv<Q: Hash<S> + Equiv<K>>(&self, key: &Q) -> bool { + self.search_equiv(key).is_some() + } + + /// Return the value corresponding to the key in the map, using + /// equivalence. + /// + /// See [pop_equiv](#method.pop_equiv) for an extended example. + pub fn find_equiv<'a, Q: Hash<S> + Equiv<K>>(&'a self, k: &Q) -> Option<&'a V> { + match self.search_equiv(k) { + None => None, + Some(bucket) => { + let (_, v_ref) = bucket.into_refs(); + Some(v_ref) + } + } + } + + /// Remove an equivalent key from the map, returning the value at the + /// key if the key was previously in the map. + /// + /// # Example + /// + /// This is a slightly silly example where we define the number's + /// parity as the equivalence class. It is important that the + /// values hash the same, which is why we implement `Hash`. + /// + /// ``` + /// use std::collections::HashMap; + /// use std::hash::Hash; + /// use std::hash::sip::SipState; + /// + /// #[deriving(Eq, PartialEq)] + /// struct EvenOrOdd { + /// num: uint + /// }; + /// + /// impl Hash for EvenOrOdd { + /// fn hash(&self, state: &mut SipState) { + /// let parity = self.num % 2; + /// parity.hash(state); + /// } + /// } + /// + /// impl Equiv<EvenOrOdd> for EvenOrOdd { + /// fn equiv(&self, other: &EvenOrOdd) -> bool { + /// self.num % 2 == other.num % 2 + /// } + /// } + /// + /// let mut map = HashMap::new(); + /// map.insert(EvenOrOdd { num: 3 }, "foo"); + /// + /// assert!(map.contains_key_equiv(&EvenOrOdd { num: 1 })); + /// assert!(!map.contains_key_equiv(&EvenOrOdd { num: 4 })); + /// + /// assert_eq!(map.find_equiv(&EvenOrOdd { num: 5 }), Some(&"foo")); + /// assert_eq!(map.find_equiv(&EvenOrOdd { num: 2 }), None); + /// + /// assert_eq!(map.pop_equiv(&EvenOrOdd { num: 1 }), Some("foo")); + /// assert_eq!(map.pop_equiv(&EvenOrOdd { num: 2 }), None); + /// + /// ``` + #[experimental] + pub fn pop_equiv<Q:Hash<S> + Equiv<K>>(&mut self, k: &Q) -> Option<V> { + if self.table.size() == 0 { + return None + } + + let potential_new_size = self.table.size() - 1; + self.make_some_room(potential_new_size); + + match self.search_equiv_mut(k) { + Some(bucket) => { + Some(pop_internal(bucket)) + } + _ => None + } + } + + /// An iterator visiting all keys in arbitrary order. + /// Iterator element type is `&'a K`. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// map.insert("a", 1i); + /// map.insert("b", 2); + /// map.insert("c", 3); + /// + /// for key in map.keys() { + /// println!("{}", key); + /// } + /// ``` + pub fn keys(&self) -> Keys<K, V> { + self.iter().map(|(k, _v)| k) + } + + /// An iterator visiting all values in arbitrary order. + /// Iterator element type is `&'a V`. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// map.insert("a", 1i); + /// map.insert("b", 2); + /// map.insert("c", 3); + /// + /// for key in map.values() { + /// println!("{}", key); + /// } + /// ``` + pub fn values(&self) -> Values<K, V> { + self.iter().map(|(_k, v)| v) + } + + /// An iterator visiting all key-value pairs in arbitrary order. + /// Iterator element type is `(&'a K, &'a V)`. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// map.insert("a", 1i); + /// map.insert("b", 2); + /// map.insert("c", 3); + /// + /// for (key, val) in map.iter() { + /// println!("key: {} val: {}", key, val); + /// } + /// ``` + pub fn iter(&self) -> Entries<K, V> { + Entries { inner: self.table.iter() } + } + + /// An iterator visiting all key-value pairs in arbitrary order, + /// with mutable references to the values. + /// Iterator element type is `(&'a K, &'a mut V)`. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// map.insert("a", 1i); + /// map.insert("b", 2); + /// map.insert("c", 3); + /// + /// // Update all values + /// for (_, val) in map.mut_iter() { + /// *val *= 2; + /// } + /// + /// for (key, val) in map.iter() { + /// println!("key: {} val: {}", key, val); + /// } + /// ``` + pub fn mut_iter(&mut self) -> MutEntries<K, V> { + MutEntries { inner: self.table.mut_iter() } + } + + /// 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. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map = HashMap::new(); + /// map.insert("a", 1i); + /// map.insert("b", 2); + /// map.insert("c", 3); + /// + /// // Not possible with .iter() + /// let vec: Vec<(&str, int)> = map.move_iter().collect(); + /// ``` + pub fn move_iter(self) -> MoveEntries<K, V> { + MoveEntries { + inner: self.table.move_iter().map(|(_, k, v)| (k, v)) + } + } +} + +impl<K: Eq + Hash<S>, V: Clone, S, H: Hasher<S>> HashMap<K, V, H> { + /// Return a copy of the value corresponding to the key. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map: HashMap<uint, String> = HashMap::new(); + /// map.insert(1u, "foo".to_string()); + /// let s: String = map.find_copy(&1).unwrap(); + /// ``` + pub fn find_copy(&self, k: &K) -> Option<V> { + self.find(k).map(|v| (*v).clone()) + } + + /// Return a copy of the value corresponding to the key. + /// + /// # Failure + /// + /// Fails if the key is not present. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashMap; + /// + /// let mut map: HashMap<uint, String> = HashMap::new(); + /// map.insert(1u, "foo".to_string()); + /// let s: String = map.get_copy(&1); + /// ``` + pub fn get_copy(&self, k: &K) -> V { + (*self.get(k)).clone() + } +} + +impl<K: Eq + Hash<S>, V: PartialEq, S, H: Hasher<S>> PartialEq for HashMap<K, V, H> { + fn eq(&self, other: &HashMap<K, V, H>) -> bool { + if self.len() != other.len() { return false; } + + self.iter().all(|(key, value)| + other.find(key).map_or(false, |v| *value == *v) + ) + } +} + +impl<K: Eq + Hash<S>, V: Eq, S, H: Hasher<S>> Eq for HashMap<K, V, H> {} + +impl<K: Eq + Hash<S> + Show, V: Show, S, H: Hasher<S>> Show for HashMap<K, V, H> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + try!(write!(f, "{{")); + + for (i, (k, v)) in self.iter().enumerate() { + if i != 0 { try!(write!(f, ", ")); } + try!(write!(f, "{}: {}", *k, *v)); + } + + write!(f, "}}") + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> Default for HashMap<K, V, H> { + fn default() -> HashMap<K, V, H> { + HashMap::with_hasher(Default::default()) + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> Index<K, V> for HashMap<K, V, H> { + #[inline] + fn index<'a>(&'a self, index: &K) -> &'a V { + self.get(index) + } +} + +// FIXME(#12825) Indexing will always try IndexMut first and that causes issues. +/*impl<K: Eq + Hash<S>, V, S, H: Hasher<S>> ops::IndexMut<K, V> for HashMap<K, V, H> { + #[inline] + fn index_mut<'a>(&'a mut self, index: &K) -> &'a mut V { + self.get_mut(index) + } +}*/ + +/// HashMap iterator +pub struct Entries<'a, K: 'a, V: 'a> { + inner: table::Entries<'a, K, V> +} + +/// HashMap mutable values iterator +pub struct MutEntries<'a, K: 'a, V: 'a> { + inner: table::MutEntries<'a, K, V> +} + +/// HashMap move iterator +pub struct MoveEntries<K, V> { + inner: iter::Map<'static, (SafeHash, K, V), (K, V), table::MoveEntries<K, V>> +} + +impl<'a, K, V> Iterator<(&'a K, &'a V)> for Entries<'a, K, V> { + #[inline] + fn next(&mut self) -> Option<(&'a K, &'a V)> { + self.inner.next() + } + #[inline] + fn size_hint(&self) -> (uint, Option<uint>) { + self.inner.size_hint() + } +} + +impl<'a, K, V> Iterator<(&'a K, &'a mut V)> for MutEntries<'a, K, V> { + #[inline] + fn next(&mut self) -> Option<(&'a K, &'a mut V)> { + self.inner.next() + } + #[inline] + fn size_hint(&self) -> (uint, Option<uint>) { + self.inner.size_hint() + } +} + +impl<K, V> Iterator<(K, V)> for MoveEntries<K, V> { + #[inline] + fn next(&mut self) -> Option<(K, V)> { + self.inner.next() + } + #[inline] + fn size_hint(&self) -> (uint, Option<uint>) { + self.inner.size_hint() + } +} + +/// HashMap keys iterator +pub type Keys<'a, K, V> = + iter::Map<'static, (&'a K, &'a V), &'a K, Entries<'a, K, V>>; + +/// HashMap values iterator +pub type Values<'a, K, V> = + iter::Map<'static, (&'a K, &'a V), &'a V, Entries<'a, K, V>>; + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> FromIterator<(K, V)> for HashMap<K, V, H> { + fn from_iter<T: Iterator<(K, V)>>(iter: T) -> HashMap<K, V, H> { + let (lower, _) = iter.size_hint(); + let mut map = HashMap::with_capacity_and_hasher(lower, Default::default()); + map.extend(iter); + map + } +} + +impl<K: Eq + Hash<S>, V, S, H: Hasher<S> + Default> Extendable<(K, V)> for HashMap<K, V, H> { + fn extend<T: Iterator<(K, V)>>(&mut self, mut iter: T) { + for (k, v) in iter { + self.insert(k, v); + } + } +} + +#[cfg(test)] +mod test_map { + use prelude::*; + + use super::HashMap; + use cmp::Equiv; + use hash; + use iter::{Iterator,range_inclusive,range_step_inclusive}; + use cell::RefCell; + + struct KindaIntLike(int); + + impl Equiv<int> for KindaIntLike { + fn equiv(&self, other: &int) -> bool { + let KindaIntLike(this) = *self; + this == *other + } + } + impl<S: hash::Writer> hash::Hash<S> for KindaIntLike { + fn hash(&self, state: &mut S) { + let KindaIntLike(this) = *self; + this.hash(state) + } + } + + #[test] + fn test_create_capacity_zero() { + let mut m = HashMap::with_capacity(0); + + assert!(m.insert(1i, 1i)); + + 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(1i, 2i)); + assert_eq!(m.len(), 1); + assert!(m.insert(2i, 4i)); + assert_eq!(m.len(), 2); + assert_eq!(*m.find(&1).unwrap(), 2); + assert_eq!(*m.find(&2).unwrap(), 4); + } + + local_data_key!(drop_vector: RefCell<Vec<int>>) + + #[deriving(Hash, PartialEq, Eq)] + struct Dropable { + k: uint + } + + impl Dropable { + fn new(k: uint) -> Dropable { + let v = drop_vector.get().unwrap(); + v.borrow_mut().as_mut_slice()[k] += 1; + + Dropable { k: k } + } + } + + impl Drop for Dropable { + fn drop(&mut self) { + let v = drop_vector.get().unwrap(); + v.borrow_mut().as_mut_slice()[self.k] -= 1; + } + } + + impl Clone for Dropable { + fn clone(&self) -> Dropable { + Dropable::new(self.k) + } + } + + #[test] + fn test_drops() { + drop_vector.replace(Some(RefCell::new(Vec::from_elem(200, 0i)))); + + { + let mut m = HashMap::new(); + + let v = drop_vector.get().unwrap(); + for i in range(0u, 200) { + assert_eq!(v.borrow().as_slice()[i], 0); + } + drop(v); + + for i in range(0u, 100) { + let d1 = Dropable::new(i); + let d2 = Dropable::new(i+100); + m.insert(d1, d2); + } + + let v = drop_vector.get().unwrap(); + for i in range(0u, 200) { + assert_eq!(v.borrow().as_slice()[i], 1); + } + drop(v); + + for i in range(0u, 50) { + let k = Dropable::new(i); + let v = m.pop(&k); + + assert!(v.is_some()); + + let v = drop_vector.get().unwrap(); + assert_eq!(v.borrow().as_slice()[i], 1); + assert_eq!(v.borrow().as_slice()[i+100], 1); + } + + let v = drop_vector.get().unwrap(); + for i in range(0u, 50) { + assert_eq!(v.borrow().as_slice()[i], 0); + assert_eq!(v.borrow().as_slice()[i+100], 0); + } + + for i in range(50u, 100) { + assert_eq!(v.borrow().as_slice()[i], 1); + assert_eq!(v.borrow().as_slice()[i+100], 1); + } + } + + let v = drop_vector.get().unwrap(); + for i in range(0u, 200) { + assert_eq!(v.borrow().as_slice()[i], 0); + } + } + + #[test] + fn test_move_iter_drops() { + drop_vector.replace(Some(RefCell::new(Vec::from_elem(200, 0i)))); + + let hm = { + let mut hm = HashMap::new(); + + let v = drop_vector.get().unwrap(); + for i in range(0u, 200) { + assert_eq!(v.borrow().as_slice()[i], 0); + } + drop(v); + + for i in range(0u, 100) { + let d1 = Dropable::new(i); + let d2 = Dropable::new(i+100); + hm.insert(d1, d2); + } + + let v = drop_vector.get().unwrap(); + for i in range(0u, 200) { + assert_eq!(v.borrow().as_slice()[i], 1); + } + drop(v); + + hm + }; + + // By the way, ensure that cloning doesn't screw up the dropping. + drop(hm.clone()); + + { + let mut half = hm.move_iter().take(50); + + let v = drop_vector.get().unwrap(); + for i in range(0u, 200) { + assert_eq!(v.borrow().as_slice()[i], 1); + } + drop(v); + + for _ in half {} + + let v = drop_vector.get().unwrap(); + let nk = range(0u, 100).filter(|&i| { + v.borrow().as_slice()[i] == 1 + }).count(); + + let nv = range(0u, 100).filter(|&i| { + v.borrow().as_slice()[i+100] == 1 + }).count(); + + assert_eq!(nk, 50); + assert_eq!(nv, 50); + }; + + let v = drop_vector.get().unwrap(); + for i in range(0u, 200) { + assert_eq!(v.borrow().as_slice()[i], 0); + } + } + + #[test] + fn test_empty_pop() { + let mut m: HashMap<int, bool> = HashMap::new(); + assert_eq!(m.pop(&0), 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 range(0i, 10) { + assert!(m.is_empty()); + + for i in range_inclusive(1i, 1000) { + assert!(m.insert(i, i)); + + for j in range_inclusive(1, i) { + let r = m.find(&j); + assert_eq!(r, Some(&j)); + } + + for j in range_inclusive(i+1, 1000) { + let r = m.find(&j); + assert_eq!(r, None); + } + } + + for i in range_inclusive(1001i, 2000) { + assert!(!m.contains_key(&i)); + } + + // remove forwards + for i in range_inclusive(1i, 1000) { + assert!(m.remove(&i)); + + for j in range_inclusive(1, i) { + assert!(!m.contains_key(&j)); + } + + for j in range_inclusive(i+1, 1000) { + assert!(m.contains_key(&j)); + } + } + + for i in range_inclusive(1i, 1000) { + assert!(!m.contains_key(&i)); + } + + for i in range_inclusive(1i, 1000) { + assert!(m.insert(i, i)); + } + + // remove backwards + for i in range_step_inclusive(1000i, 1, -1) { + assert!(m.remove(&i)); + + for j in range_inclusive(i, 1000) { + assert!(!m.contains_key(&j)); + } + + for j in range_inclusive(1, i-1) { + assert!(m.contains_key(&j)); + } + } + } + } + + #[test] + fn test_find_mut() { + let mut m = HashMap::new(); + assert!(m.insert(1i, 12i)); + assert!(m.insert(2i, 8i)); + assert!(m.insert(5i, 14i)); + let new = 100; + match m.find_mut(&5) { + None => fail!(), Some(x) => *x = new + } + assert_eq!(m.find(&5), Some(&new)); + } + + #[test] + fn test_insert_overwrite() { + let mut m = HashMap::new(); + assert!(m.insert(1i, 2i)); + assert_eq!(*m.find(&1).unwrap(), 2); + assert!(!m.insert(1i, 3i)); + assert_eq!(*m.find(&1).unwrap(), 3); + } + + #[test] + fn test_insert_conflicts() { + let mut m = HashMap::with_capacity(4); + assert!(m.insert(1i, 2i)); + assert!(m.insert(5i, 3i)); + assert!(m.insert(9i, 4i)); + assert_eq!(*m.find(&9).unwrap(), 4); + assert_eq!(*m.find(&5).unwrap(), 3); + assert_eq!(*m.find(&1).unwrap(), 2); + } + + #[test] + fn test_update_with() { + let mut m = HashMap::with_capacity(4); + assert!(m.insert(1i, 2i)); + + for i in range(1i, 1000) { + assert_eq!( + i + 2, + *m.insert_or_update_with(i + 1, i + 2, |_k, _v| { + fail!("Key not yet present"); + }) + ); + assert_eq!( + i + 1, + *m.insert_or_update_with(i, i + 3, |k, v| { + assert_eq!(*k, i); + assert_eq!(*v, i + 1); + }) + ); + } + } + + #[test] + fn test_conflict_remove() { + let mut m = HashMap::with_capacity(4); + assert!(m.insert(1i, 2i)); + assert_eq!(*m.find(&1).unwrap(), 2); + assert!(m.insert(5, 3)); + assert_eq!(*m.find(&1).unwrap(), 2); + assert_eq!(*m.find(&5).unwrap(), 3); + assert!(m.insert(9, 4)); + assert_eq!(*m.find(&1).unwrap(), 2); + assert_eq!(*m.find(&5).unwrap(), 3); + assert_eq!(*m.find(&9).unwrap(), 4); + assert!(m.remove(&1)); + assert_eq!(*m.find(&9).unwrap(), 4); + assert_eq!(*m.find(&5).unwrap(), 3); + } + + #[test] + fn test_is_empty() { + let mut m = HashMap::with_capacity(4); + assert!(m.insert(1i, 2i)); + assert!(!m.is_empty()); + assert!(m.remove(&1)); + assert!(m.is_empty()); + } + + #[test] + fn test_pop() { + let mut m = HashMap::new(); + m.insert(1i, 2i); + assert_eq!(m.pop(&1), Some(2)); + assert_eq!(m.pop(&1), None); + } + + #[test] + #[allow(experimental)] + fn test_pop_equiv() { + let mut m = HashMap::new(); + m.insert(1i, 2i); + assert_eq!(m.pop_equiv(&KindaIntLike(1)), Some(2)); + assert_eq!(m.pop_equiv(&KindaIntLike(1)), None); + } + + #[test] + fn test_swap() { + let mut m = HashMap::new(); + assert_eq!(m.swap(1i, 2i), None); + assert_eq!(m.swap(1i, 3i), Some(2)); + assert_eq!(m.swap(1i, 4i), Some(3)); + } + + #[test] + fn test_iterate() { + let mut m = HashMap::with_capacity(4); + for i in range(0u, 32) { + assert!(m.insert(i, i*2)); + } + assert_eq!(m.len(), 32); + + let mut observed: u32 = 0; + + for (k, v) in m.iter() { + assert_eq!(*v, *k * 2); + observed |= 1 << *k; + } + assert_eq!(observed, 0xFFFF_FFFF); + } + + #[test] + fn test_keys() { + let vec = vec![(1i, 'a'), (2i, 'b'), (3i, 'c')]; + let map = vec.move_iter().collect::<HashMap<int, char>>(); + let keys = map.keys().map(|&k| k).collect::<Vec<int>>(); + assert_eq!(keys.len(), 3); + assert!(keys.contains(&1)); + assert!(keys.contains(&2)); + assert!(keys.contains(&3)); + } + + #[test] + fn test_values() { + let vec = vec![(1i, 'a'), (2i, 'b'), (3i, 'c')]; + let map = vec.move_iter().collect::<HashMap<int, char>>(); + let values = map.values().map(|&v| v).collect::<Vec<char>>(); + assert_eq!(values.len(), 3); + assert!(values.contains(&'a')); + assert!(values.contains(&'b')); + assert!(values.contains(&'c')); + } + + #[test] + fn test_find() { + let mut m = HashMap::new(); + assert!(m.find(&1i).is_none()); + m.insert(1i, 2i); + match m.find(&1) { + None => fail!(), + Some(v) => assert_eq!(*v, 2) + } + } + + #[test] + fn test_find_copy() { + let mut m = HashMap::new(); + assert!(m.find(&1i).is_none()); + + for i in range(1i, 10000) { + m.insert(i, i + 7); + match m.find_copy(&i) { + None => fail!(), + Some(v) => assert_eq!(v, i + 7) + } + for j in range(1i, i/100) { + match m.find_copy(&j) { + None => fail!(), + Some(v) => assert_eq!(v, j + 7) + } + } + } + } + + #[test] + fn test_eq() { + let mut m1 = HashMap::new(); + m1.insert(1i, 2i); + m1.insert(2i, 3i); + m1.insert(3i, 4i); + + let mut m2 = HashMap::new(); + m2.insert(1i, 2i); + m2.insert(2i, 3i); + + assert!(m1 != m2); + + m2.insert(3i, 4i); + + assert_eq!(m1, m2); + } + + #[test] + fn test_show() { + let mut map: HashMap<int, int> = HashMap::new(); + let empty: HashMap<int, int> = HashMap::new(); + + map.insert(1i, 2i); + map.insert(3i, 4i); + + let map_str = format!("{}", map); + + assert!(map_str == "{1: 2, 3: 4}".to_string() || map_str == "{3: 4, 1: 2}".to_string()); + assert_eq!(format!("{}", empty), "{}".to_string()); + } + + #[test] + fn test_expand() { + let mut m = HashMap::new(); + + assert_eq!(m.len(), 0); + assert!(m.is_empty()); + + let mut i = 0u; + let old_cap = m.table.capacity(); + while old_cap == m.table.capacity() { + m.insert(i, i); + i += 1; + } + + assert_eq!(m.len(), i); + assert!(!m.is_empty()); + } + + #[test] + fn test_resize_policy() { + let mut m = HashMap::new(); + + assert_eq!(m.len(), 0); + assert_eq!(m.table.capacity(), 0); + assert!(m.is_empty()); + + m.insert(0, 0); + m.remove(&0); + assert!(m.is_empty()); + let initial_cap = m.table.capacity(); + m.reserve(initial_cap * 2); + let cap = m.table.capacity(); + + assert_eq!(cap, initial_cap * 2); + + let mut i = 0u; + for _ in range(0, cap * 3 / 4) { + m.insert(i, i); + i += 1; + } + // three quarters full + + assert_eq!(m.len(), i); + assert_eq!(m.table.capacity(), cap); + + for _ in range(0, cap / 4) { + m.insert(i, i); + i += 1; + } + // half full + + let new_cap = m.table.capacity(); + assert_eq!(new_cap, cap * 2); + + for _ in range(0, cap / 2 - 1) { + i -= 1; + m.remove(&i); + assert_eq!(m.table.capacity(), new_cap); + } + // A little more than one quarter full. + // Shrinking starts as we remove more elements: + for _ in range(0, cap / 2 - 1) { + i -= 1; + m.remove(&i); + } + + assert_eq!(m.len(), i); + assert!(!m.is_empty()); + assert_eq!(m.table.capacity(), cap); + } + + #[test] + fn test_find_equiv() { + let mut m = HashMap::new(); + + let (foo, bar, baz) = (1i,2i,3i); + m.insert("foo".to_string(), foo); + m.insert("bar".to_string(), bar); + m.insert("baz".to_string(), baz); + + + assert_eq!(m.find_equiv(&("foo")), Some(&foo)); + assert_eq!(m.find_equiv(&("bar")), Some(&bar)); + assert_eq!(m.find_equiv(&("baz")), Some(&baz)); + + assert_eq!(m.find_equiv(&("qux")), None); + } + + #[test] + fn test_from_iter() { + let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; + + let map: HashMap<int, int> = xs.iter().map(|&x| x).collect(); + + for &(k, v) in xs.iter() { + assert_eq!(map.find(&k), Some(&v)); + } + } + + #[test] + fn test_size_hint() { + let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; + + let map: HashMap<int, int> = xs.iter().map(|&x| x).collect(); + + let mut iter = map.iter(); + + for _ in iter.by_ref().take(3) {} + + assert_eq!(iter.size_hint(), (3, Some(3))); + } + + #[test] + fn test_mut_size_hint() { + let xs = [(1i, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)]; + + let mut map: HashMap<int, int> = xs.iter().map(|&x| x).collect(); + + let mut iter = map.mut_iter(); + + for _ in iter.by_ref().take(3) {} + + assert_eq!(iter.size_hint(), (3, Some(3))); + } + + #[test] + fn test_index() { + let mut map: HashMap<int, int> = HashMap::new(); + + map.insert(1, 2); + map.insert(2, 1); + map.insert(3, 4); + + assert_eq!(map[2], 1); + } + + #[test] + #[should_fail] + fn test_index_nonexistent() { + let mut map: HashMap<int, int> = HashMap::new(); + + map.insert(1, 2); + map.insert(2, 1); + map.insert(3, 4); + + map[4]; + } +} diff --git a/src/libstd/collections/hashmap/mod.rs b/src/libstd/collections/hashmap/mod.rs new file mode 100644 index 00000000000..b5612ce0f07 --- /dev/null +++ b/src/libstd/collections/hashmap/mod.rs @@ -0,0 +1,28 @@ +// 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 + +pub use self::map::HashMap; +pub use self::map::Entries; +pub use self::map::MutEntries; +pub use self::map::MoveEntries; +pub use self::map::Keys; +pub use self::map::Values; +pub use self::map::INITIAL_CAPACITY; +pub use self::set::HashSet; +pub use self::set::SetItems; +pub use self::set::SetMoveItems; +pub use self::set::SetAlgebraItems; + +mod bench; +mod map; +mod set; +mod table; diff --git a/src/libstd/collections/hashmap/set.rs b/src/libstd/collections/hashmap/set.rs new file mode 100644 index 00000000000..4a2a04cbc9f --- /dev/null +++ b/src/libstd/collections/hashmap/set.rs @@ -0,0 +1,703 @@ +// 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. +// +// ignore-lexer-test FIXME #15883 + +use clone::Clone; +use cmp::{Eq, Equiv, PartialEq}; +use collections::{Collection, Mutable, Set, MutableSet, Map, MutableMap}; +use default::Default; +use fmt::Show; +use fmt; +use hash::{Hash, Hasher, RandomSipHasher}; +use iter::{Iterator, FromIterator, FilterMap, Chain, Repeat, Zip, Extendable}; +use iter; +use option::{Some, None}; +use result::{Ok, Err}; + +use super::{HashMap, Entries, MoveEntries, INITIAL_CAPACITY}; + + +// 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. + +/// An implementation of a hash set using the underlying representation of a +/// HashMap where the value is (). As with the `HashMap` type, a `HashSet` +/// requires that the elements implement the `Eq` and `Hash` traits. +/// +/// # Example +/// +/// ``` +/// use std::collections::HashSet; +/// // Type inference lets us omit an explicit type signature (which +/// // would be `HashSet<&str>` in this example). +/// let mut books = HashSet::new(); +/// +/// // Add some books. +/// books.insert("A Dance With Dragons"); +/// books.insert("To Kill a Mockingbird"); +/// books.insert("The Odyssey"); +/// books.insert("The Great Gatsby"); +/// +/// // 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.iter() { +/// 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; +/// #[deriving(Hash, Eq, PartialEq, Show)] +/// struct Viking<'a> { +/// name: &'a str, +/// power: uint, +/// } +/// +/// let mut vikings = HashSet::new(); +/// +/// vikings.insert(Viking { name: "Einar", power: 9u }); +/// vikings.insert(Viking { name: "Einar", power: 9u }); +/// vikings.insert(Viking { name: "Olaf", power: 4u }); +/// vikings.insert(Viking { name: "Harald", power: 8u }); +/// +/// // Use derived implementation to print the vikings. +/// for x in vikings.iter() { +/// println!("{}", x); +/// } +/// ``` +#[deriving(Clone)] +pub struct HashSet<T, H = RandomSipHasher> { + map: HashMap<T, (), H> +} + +impl<T: Hash + Eq> HashSet<T, RandomSipHasher> { + /// Create an empty HashSet. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// let mut set: HashSet<int> = HashSet::new(); + /// ``` + #[inline] + pub fn new() -> HashSet<T, RandomSipHasher> { + HashSet::with_capacity(INITIAL_CAPACITY) + } + + /// Create an empty HashSet with space for at least `n` elements in + /// the hash table. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// let mut set: HashSet<int> = HashSet::with_capacity(10); + /// ``` + #[inline] + pub fn with_capacity(capacity: uint) -> HashSet<T, RandomSipHasher> { + HashSet { map: HashMap::with_capacity(capacity) } + } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S>> HashSet<T, H> { + /// 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. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// use std::hash::sip::SipHasher; + /// + /// let h = SipHasher::new(); + /// let mut set = HashSet::with_hasher(h); + /// set.insert(2u); + /// ``` + #[inline] + pub fn with_hasher(hasher: H) -> HashSet<T, H> { + HashSet::with_capacity_and_hasher(INITIAL_CAPACITY, hasher) + } + + /// Create an empty HashSet with space for at least `capacity` + /// elements in the hash table, using `hasher` to hash the keys. + /// + /// 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. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// use std::hash::sip::SipHasher; + /// + /// let h = SipHasher::new(); + /// let mut set = HashSet::with_capacity_and_hasher(10u, h); + /// set.insert(1i); + /// ``` + #[inline] + pub fn with_capacity_and_hasher(capacity: uint, hasher: H) -> HashSet<T, H> { + HashSet { map: HashMap::with_capacity_and_hasher(capacity, hasher) } + } + + /// Reserve space for at least `n` elements in the hash table. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// let mut set: HashSet<int> = HashSet::new(); + /// set.reserve(10); + /// ``` + pub fn reserve(&mut self, n: uint) { + self.map.reserve(n) + } + + /// Returns true if the hash set contains a value equivalent to the + /// given query value. + /// + /// # Example + /// + /// This is a slightly silly example where we define the number's + /// parity as the equivilance class. It is important that the + /// values hash the same, which is why we implement `Hash`. + /// + /// ``` + /// use std::collections::HashSet; + /// use std::hash::Hash; + /// use std::hash::sip::SipState; + /// + /// #[deriving(Eq, PartialEq)] + /// struct EvenOrOdd { + /// num: uint + /// }; + /// + /// impl Hash for EvenOrOdd { + /// fn hash(&self, state: &mut SipState) { + /// let parity = self.num % 2; + /// parity.hash(state); + /// } + /// } + /// + /// impl Equiv<EvenOrOdd> for EvenOrOdd { + /// fn equiv(&self, other: &EvenOrOdd) -> bool { + /// self.num % 2 == other.num % 2 + /// } + /// } + /// + /// let mut set = HashSet::new(); + /// set.insert(EvenOrOdd { num: 3u }); + /// + /// assert!(set.contains_equiv(&EvenOrOdd { num: 3u })); + /// assert!(set.contains_equiv(&EvenOrOdd { num: 5u })); + /// assert!(!set.contains_equiv(&EvenOrOdd { num: 4u })); + /// assert!(!set.contains_equiv(&EvenOrOdd { num: 2u })); + /// + /// ``` + pub fn contains_equiv<Q: Hash<S> + Equiv<T>>(&self, value: &Q) -> bool { + self.map.contains_key_equiv(value) + } + + /// An iterator visiting all elements in arbitrary order. + /// Iterator element type is &'a T. + /// + /// # Example + /// + /// ``` + /// 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); + /// } + /// ``` + pub fn iter<'a>(&'a self) -> SetItems<'a, T> { + self.map.keys() + } + + /// 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. + /// + /// # Example + /// + /// ``` + /// 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.move_iter().collect(); + /// + /// // Will print in an arbitrary order. + /// for x in v.iter() { + /// println!("{}", x); + /// } + /// ``` + pub fn move_iter(self) -> SetMoveItems<T> { + self.map.move_iter().map(|(k, _)| k) + } + + /// Visit the values representing the difference. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); + /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); + /// + /// // Can be seen as `a - b`. + /// for x in a.difference(&b) { + /// println!("{}", x); // Print 1 + /// } + /// + /// let diff: HashSet<int> = a.difference(&b).map(|&x| x).collect(); + /// assert_eq!(diff, [1i].iter().map(|&x| x).collect()); + /// + /// // Note that difference is not symmetric, + /// // and `b - a` means something else: + /// let diff: HashSet<int> = b.difference(&a).map(|&x| x).collect(); + /// assert_eq!(diff, [4i].iter().map(|&x| x).collect()); + /// ``` + pub fn difference<'a>(&'a self, other: &'a HashSet<T, H>) -> SetAlgebraItems<'a, T, H> { + Repeat::new(other).zip(self.iter()) + .filter_map(|(other, elt)| { + if !other.contains(elt) { Some(elt) } else { None } + }) + } + + /// Visit the values representing the symmetric difference. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); + /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); + /// + /// // Print 1, 4 in arbitrary order. + /// for x in a.symmetric_difference(&b) { + /// println!("{}", x); + /// } + /// + /// let diff1: HashSet<int> = a.symmetric_difference(&b).map(|&x| x).collect(); + /// let diff2: HashSet<int> = b.symmetric_difference(&a).map(|&x| x).collect(); + /// + /// assert_eq!(diff1, diff2); + /// assert_eq!(diff1, [1i, 4].iter().map(|&x| x).collect()); + /// ``` + pub fn symmetric_difference<'a>(&'a self, other: &'a HashSet<T, H>) + -> Chain<SetAlgebraItems<'a, T, H>, SetAlgebraItems<'a, T, H>> { + self.difference(other).chain(other.difference(self)) + } + + /// Visit the values representing the intersection. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); + /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); + /// + /// // Print 2, 3 in arbitrary order. + /// for x in a.intersection(&b) { + /// println!("{}", x); + /// } + /// + /// let diff: HashSet<int> = a.intersection(&b).map(|&x| x).collect(); + /// assert_eq!(diff, [2i, 3].iter().map(|&x| x).collect()); + /// ``` + pub fn intersection<'a>(&'a self, other: &'a HashSet<T, H>) + -> SetAlgebraItems<'a, T, H> { + Repeat::new(other).zip(self.iter()) + .filter_map(|(other, elt)| { + if other.contains(elt) { Some(elt) } else { None } + }) + } + + /// Visit the values representing the union. + /// + /// # Example + /// + /// ``` + /// use std::collections::HashSet; + /// let a: HashSet<int> = [1i, 2, 3].iter().map(|&x| x).collect(); + /// let b: HashSet<int> = [4i, 2, 3, 4].iter().map(|&x| x).collect(); + /// + /// // Print 1, 2, 3, 4 in arbitrary order. + /// for x in a.union(&b) { + /// println!("{}", x); + /// } + /// + /// let diff: HashSet<int> = a.union(&b).map(|&x| x).collect(); + /// assert_eq!(diff, [1i, 2, 3, 4].iter().map(|&x| x).collect()); + /// ``` + pub fn union<'a>(&'a self, other: &'a HashSet<T, H>) + -> Chain<SetItems<'a, T>, SetAlgebraItems<'a, T, H>> { + self.iter().chain(other.difference(self)) + } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S>> PartialEq for HashSet<T, H> { + fn eq(&self, other: &HashSet<T, H>) -> bool { + if self.len() != other.len() { return false; } + + self.iter().all(|key| other.contains(key)) + } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S>> Eq for HashSet<T, H> {} + +impl<T: Eq + Hash<S>, S, H: Hasher<S>> Collection for HashSet<T, H> { + fn len(&self) -> uint { self.map.len() } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S>> Mutable for HashSet<T, H> { + fn clear(&mut self) { self.map.clear() } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S>> Set<T> for HashSet<T, H> { + fn contains(&self, value: &T) -> bool { self.map.contains_key(value) } + + fn is_disjoint(&self, other: &HashSet<T, H>) -> bool { + self.iter().all(|v| !other.contains(v)) + } + + fn is_subset(&self, other: &HashSet<T, H>) -> bool { + self.iter().all(|v| other.contains(v)) + } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S>> MutableSet<T> for HashSet<T, H> { + fn insert(&mut self, value: T) -> bool { self.map.insert(value, ()) } + + fn remove(&mut self, value: &T) -> bool { self.map.remove(value) } +} + +impl<T: Eq + Hash<S> + fmt::Show, S, H: Hasher<S>> fmt::Show for HashSet<T, H> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + try!(write!(f, "{{")); + + for (i, x) in self.iter().enumerate() { + if i != 0 { try!(write!(f, ", ")); } + try!(write!(f, "{}", *x)); + } + + write!(f, "}}") + } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S> + Default> FromIterator<T> for HashSet<T, H> { + fn from_iter<I: Iterator<T>>(iter: I) -> HashSet<T, H> { + let (lower, _) = iter.size_hint(); + let mut set = HashSet::with_capacity_and_hasher(lower, Default::default()); + set.extend(iter); + set + } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S> + Default> Extendable<T> for HashSet<T, H> { + fn extend<I: Iterator<T>>(&mut self, mut iter: I) { + for k in iter { + self.insert(k); + } + } +} + +impl<T: Eq + Hash<S>, S, H: Hasher<S> + Default> Default for HashSet<T, H> { + fn default() -> HashSet<T, H> { + HashSet::with_hasher(Default::default()) + } +} + +/// HashSet iterator +pub type SetItems<'a, K> = + iter::Map<'static, (&'a K, &'a ()), &'a K, Entries<'a, K, ()>>; + +/// HashSet move iterator +pub type SetMoveItems<K> = + iter::Map<'static, (K, ()), K, MoveEntries<K, ()>>; + +// `Repeat` is used to feed the filter closure an explicit capture +// of a reference to the other set +/// Set operations iterator +pub type SetAlgebraItems<'a, T, H> = + FilterMap<'static, (&'a HashSet<T, H>, &'a T), &'a T, + Zip<Repeat<&'a HashSet<T, H>>, SetItems<'a, T>>>; + +#[cfg(test)] +mod test_set { + use prelude::*; + + use super::HashSet; + use slice::ImmutablePartialEqSlice; + use collections::Collection; + + #[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(5i)); + assert!(ys.insert(11i)); + 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(0i)); + assert!(a.insert(5)); + assert!(a.insert(11)); + assert!(a.insert(7)); + + let mut b = HashSet::new(); + assert!(b.insert(0i)); + 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 range(0u, 32) { + assert!(a.insert(i)); + } + let mut observed: u32 = 0; + for k in a.iter() { + 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(11i)); + 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(2i)); + 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(1i)); + assert!(a.insert(3)); + assert!(a.insert(5)); + assert!(a.insert(9)); + assert!(a.insert(11)); + + assert!(b.insert(3i)); + 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(1i)); + assert!(a.insert(3)); + assert!(a.insert(5)); + assert!(a.insert(9)); + assert!(a.insert(11)); + + assert!(b.insert(-2i)); + 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(1i)); + 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(-2i)); + 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 = [1i, 2, 3, 4, 5, 6, 7, 8, 9]; + + let set: HashSet<int> = xs.iter().map(|&x| x).collect(); + + for x in xs.iter() { + 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.move_iter().collect::<Vec<char>>(); + assert!(['a', 'b'] == v.as_slice() || ['b', 'a'] == v.as_slice()); + } + + #[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(1i); + s1.insert(2); + s1.insert(3); + + let mut s2 = HashSet::new(); + + s2.insert(1i); + s2.insert(2); + + assert!(s1 != s2); + + s2.insert(3); + + assert_eq!(s1, s2); + } + + #[test] + fn test_show() { + let mut set: HashSet<int> = HashSet::new(); + let empty: HashSet<int> = HashSet::new(); + + set.insert(1i); + set.insert(2); + + let set_str = format!("{}", set); + + assert!(set_str == "{1, 2}".to_string() || set_str == "{2, 1}".to_string()); + assert_eq!(format!("{}", empty), "{}".to_string()); + } +} diff --git a/src/libstd/collections/hashmap/table.rs b/src/libstd/collections/hashmap/table.rs new file mode 100644 index 00000000000..2edb8cd092e --- /dev/null +++ b/src/libstd/collections/hashmap/table.rs @@ -0,0 +1,896 @@ +// 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. +// +// ignore-lexer-test FIXME #15883 + +use clone::Clone; +use cmp; +use hash::{Hash, Hasher}; +use iter::{Iterator, count}; +use kinds::marker; +use mem::{min_align_of, size_of}; +use mem; +use num::{CheckedAdd, CheckedMul, is_power_of_two}; +use ops::{Deref, DerefMut, Drop}; +use option::{Some, None, Option}; +use ptr::{RawPtr, copy_nonoverlapping_memory, zero_memory}; +use ptr; +use rt::heap::{allocate, deallocate}; + +static EMPTY_BUCKET: u64 = 0u64; + +/// The raw hashtable, providing safe-ish access to the unzipped and highly +/// optimized arrays of hashes, keys, and values. +/// +/// This design uses less memory and 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". +/// +/// - All three "arrays represented by pointers" are the same length: +/// `capacity`. This is set at creation and never changes. The arrays +/// are unzipped to save space (we don't have to pay for the padding +/// between odd sized elements, such as in a map from u64 to u8), and +/// be more cache aware (scanning through 8 hashes brings in at most +/// 2 cache lines, since they're all right beside each other). +/// +/// 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>>`. +#[unsafe_no_drop_flag] +pub struct RawTable<K, V> { + capacity: uint, + size: uint, + hashes: *mut u64, + // 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::CovariantType<(K,V)>, +} + +struct RawBucket<K, V> { + hash: *mut u64, + key: *mut K, + val: *mut V +} + +pub struct Bucket<K, V, M> { + raw: RawBucket<K, V>, + idx: uint, + table: M +} + +pub struct EmptyBucket<K, V, M> { + raw: RawBucket<K, V>, + idx: uint, + table: M +} + +pub struct FullBucket<K, V, M> { + raw: RawBucket<K, V>, + idx: uint, + table: M +} + +pub type EmptyBucketImm<'table, K, V> = EmptyBucket<K, V, &'table RawTable<K, V>>; +pub type FullBucketImm<'table, K, V> = FullBucket<K, V, &'table RawTable<K, V>>; + +pub type EmptyBucketMut<'table, K, V> = EmptyBucket<K, V, &'table mut RawTable<K, V>>; +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. +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. +#[deriving(PartialEq)] +pub struct SafeHash { + hash: u64, +} + +impl SafeHash { + /// Peek at the hash value, which is guaranteed to be non-zero. + #[inline(always)] + pub fn inspect(&self) -> u64 { self.hash } +} + +/// 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: Hash<S>, S, H: Hasher<S>>(hasher: &H, t: &T) -> SafeHash { + match hasher.hash(t) { + // This constant is exceedingly likely to hash to the same + // bucket, but it won't be counted as empty! Just so we can maintain + // our precious uniform distribution of initial indexes. + EMPTY_BUCKET => SafeHash { hash: 0x8000_0000_0000_0000 }, + h => SafeHash { hash: h }, + } +} + +// `replace` casts a `*u64` 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 `u64` with a different name, this is +// safe. +// +// This test ensures that a `SafeHash` really IS the same size as a +// `u64`. 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_u64() { + assert_eq!(size_of::<SafeHash>(), size_of::<u64>()) +} + +impl<K, V> RawBucket<K, V> { + unsafe fn offset(self, count: int) -> RawBucket<K, V> { + RawBucket { + hash: self.hash.offset(count), + key: self.key.offset(count), + val: self.val.offset(count), + } + } +} + +// For parameterizing over mutability. +impl<'t, K, V> Deref<RawTable<K, V>> for &'t RawTable<K, V> { + fn deref(&self) -> &RawTable<K, V> { + &**self + } +} + +impl<'t, K, V> Deref<RawTable<K, V>> for &'t mut RawTable<K, V> { + fn deref(&self) -> &RawTable<K,V> { + &**self + } +} + +impl<'t, K, V> DerefMut<RawTable<K, V>> for &'t mut RawTable<K, V> { + fn deref_mut(&mut self) -> &mut RawTable<K,V> { + &mut **self + } +} + +// 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 + } + /// Move out the reference to the table. + pub fn into_table(self) -> M { + self.table + } + /// Get the raw index. + pub fn index(&self) -> uint { + self.idx + } +} + +impl<K, V, M> EmptyBucket<K, V, M> { + /// Borrow a reference to the table. + pub fn table(&self) -> &M { + &self.table + } + /// Move out the reference to the table. + pub fn into_table(self) -> M { + self.table + } +} + +impl<K, V, M> Bucket<K, V, M> { + /// Move out the reference to the table. + pub fn into_table(self) -> M { + self.table + } + /// Get the raw index. + pub fn index(&self) -> uint { + self.idx + } +} + +impl<K, V, M: Deref<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 uint) + } + + pub fn at_index(table: M, ib_index: uint) -> Bucket<K, V, M> { + let ib_index = ib_index & (table.capacity() - 1); + Bucket { + raw: unsafe { + table.first_bucket_raw().offset(ib_index as int) + }, + idx: ib_index, + table: table + } + } + + pub fn first(table: M) -> Bucket<K, V, M> { + Bucket { + raw: table.first_bucket_raw(), + idx: 0, + table: table + } + } + + /// 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, + idx: self.idx, + table: self.table + }), + _ => + Full(FullBucket { + raw: self.raw, + idx: self.idx, + table: self.table + }) + } + } + + /// Modifies the bucket pointer in place to make it point to the next slot. + pub fn next(&mut self) { + // Branchless bucket iteration step. + // As we reach the end of the table... + // We take the current idx: 0111111b + // Xor it by its increment: ^ 1000000b + // ------------ + // 1111111b + // Then AND with the capacity: & 1000000b + // ------------ + // to get the backwards offset: 1000000b + // ... and it's zero at all other times. + let maybe_wraparound_dist = (self.idx ^ (self.idx + 1)) & self.table.capacity(); + // Finally, we obtain the offset 1 or the offset -cap + 1. + let dist = 1i - (maybe_wraparound_dist as int); + + self.idx += 1; + + unsafe { + self.raw = self.raw.offset(dist); + } + } +} + +impl<K, V, M: Deref<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, + idx: self.idx, + table: self.table + } + } + + pub fn gap_peek(self) -> Option<GapThenFull<K, V, M>> { + let gap = EmptyBucket { + raw: self.raw, + idx: self.idx, + table: () + }; + + match self.next().peek() { + Full(bucket) => { + Some(GapThenFull { + gap: gap, + full: bucket + }) + } + Empty(..) => None + } + } +} + +impl<K, V, M: DerefMut<RawTable<K, V>>> EmptyBucket<K, V, M> { + /// 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.key, key); + ptr::write(self.raw.val, value); + } + + self.table.size += 1; + + FullBucket { raw: self.raw, idx: self.idx, table: self.table } + } +} + +impl<K, V, M: Deref<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, + idx: self.idx, + table: self.table + } + } + + /// 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 distance(&self) -> uint { + // 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.idx - self.hash().inspect() as uint) & (self.table.capacity() - 1) + } + + #[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 { + (&*self.raw.key, + &*self.raw.val) + } + } +} + +impl<K, V, M: DerefMut<RawTable<K, V>>> FullBucket<K, V, M> { + /// 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(mut self) -> (EmptyBucket<K, V, M>, K, V) { + let key = self.raw.key as *const K; + let val = self.raw.val as *const V; + + self.table.size -= 1; + + unsafe { + *self.raw.hash = EMPTY_BUCKET; + ( + EmptyBucket { + raw: self.raw, + idx: self.idx, + table: self.table + }, + ptr::read(key), + ptr::read(val) + ) + } + } + + 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 = ptr::replace(self.raw.key, k); + let old_val = ptr::replace(self.raw.val, v); + + (old_hash, old_key, old_val) + } + } + + /// Gets mutable references to the key and value at a given index. + pub fn read_mut(&mut self) -> (&mut K, &mut V) { + unsafe { + (&mut *self.raw.key, + &mut *self.raw.val) + } + } +} + +impl<'t, K, V, M: Deref<RawTable<K, V>> + 't> FullBucket<K, V, M> { + /// 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 { + (&*self.raw.key, + &*self.raw.val) + } + } +} + +impl<'t, K, V, M: DerefMut<RawTable<K, V>> + 't> FullBucket<K, V, M> { + /// 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 { + (&mut *self.raw.key, + &mut *self.raw.val) + } + } +} + +impl<K, V, M> BucketState<K, V, M> { + // For convenience. + pub fn expect_full(self) -> FullBucket<K, V, M> { + match self { + Full(full) => full, + Empty(..) => fail!("Expected full bucket") + } + } +} + +impl<K, V, M: Deref<RawTable<K, V>>> GapThenFull<K, V, M> { + #[inline] + pub fn full(&self) -> &FullBucket<K, V, M> { + &self.full + } + + pub fn shift(mut self) -> Option<GapThenFull<K, V, M>> { + unsafe { + *self.gap.raw.hash = mem::replace(&mut *self.full.raw.hash, EMPTY_BUCKET); + copy_nonoverlapping_memory(self.gap.raw.key, self.full.raw.key as *const K, 1); + copy_nonoverlapping_memory(self.gap.raw.val, self.full.raw.val as *const V, 1); + } + + let FullBucket { raw: prev_raw, idx: prev_idx, .. } = self.full; + + match self.full.next().peek() { + Full(bucket) => { + self.gap.raw = prev_raw; + self.gap.idx = prev_idx; + + self.full = bucket; + + Some(self) + } + Empty(..) => None + } + } +} + + +/// Rounds up to a multiple of a power of two. Returns the closest multiple +/// of `target_alignment` that is higher or equal to `unrounded`. +/// +/// # Failure +/// +/// Fails if `target_alignment` is not a power of two. +fn round_up_to_next(unrounded: uint, target_alignment: uint) -> uint { + assert!(is_power_of_two(target_alignment)); + (unrounded + target_alignment - 1) & !(target_alignment - 1) +} + +#[test] +fn test_rounding() { + assert_eq!(round_up_to_next(0, 4), 0); + assert_eq!(round_up_to_next(1, 4), 4); + assert_eq!(round_up_to_next(2, 4), 4); + assert_eq!(round_up_to_next(3, 4), 4); + assert_eq!(round_up_to_next(4, 4), 4); + assert_eq!(round_up_to_next(5, 4), 8); +} + +// Returns a tuple of (key_offset, val_offset), +// from the start of a mallocated array. +fn calculate_offsets(hashes_size: uint, + keys_size: uint, keys_align: uint, + vals_align: uint) + -> (uint, uint) { + let keys_offset = round_up_to_next(hashes_size, keys_align); + let end_of_keys = keys_offset + keys_size; + + let vals_offset = round_up_to_next(end_of_keys, vals_align); + + (keys_offset, vals_offset) +} + +// Returns a tuple of (minimum required malloc alignment, hash_offset, +// array_size), from the start of a mallocated array. +fn calculate_allocation(hash_size: uint, hash_align: uint, + keys_size: uint, keys_align: uint, + vals_size: uint, vals_align: uint) + -> (uint, uint, uint) { + let hash_offset = 0; + let (_, vals_offset) = calculate_offsets(hash_size, + keys_size, keys_align, + vals_align); + let end_of_vals = vals_offset + vals_size; + + let min_align = cmp::max(hash_align, cmp::max(keys_align, vals_align)); + + (min_align, hash_offset, end_of_vals) +} + +#[test] +fn test_offset_calculation() { + assert_eq!(calculate_allocation(128, 8, 15, 1, 4, 4), (8, 0, 148)); + assert_eq!(calculate_allocation(3, 1, 2, 1, 1, 1), (1, 0, 6)); + assert_eq!(calculate_allocation(6, 2, 12, 4, 24, 8), (8, 0, 48)); + assert_eq!(calculate_offsets(128, 15, 1, 4), (128, 144)); + assert_eq!(calculate_offsets(3, 2, 1, 1), (3, 5)); + assert_eq!(calculate_offsets(6, 12, 4, 8), (8, 24)); +} + +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. + unsafe fn new_uninitialized(capacity: uint) -> RawTable<K, V> { + if capacity == 0 { + return RawTable { + size: 0, + capacity: 0, + hashes: 0 as *mut u64, + marker: marker::CovariantType, + }; + } + // No need for `checked_mul` before a more restrictive check performed + // later in this method. + let hashes_size = capacity * size_of::<u64>(); + let keys_size = capacity * size_of::< K >(); + let vals_size = capacity * size_of::< V >(); + + // Allocating hashmaps is a little tricky. We need to allocate three + // 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. + // + // This is great in theory, but in practice getting the alignment + // right is a little subtle. Therefore, calculating offsets has been + // factored out into a different function. + let (malloc_alignment, hash_offset, size) = + calculate_allocation( + hashes_size, min_align_of::<u64>(), + keys_size, min_align_of::< K >(), + vals_size, min_align_of::< V >()); + + // One check for overflow that covers calculation and rounding of size. + let size_of_bucket = size_of::<u64>().checked_add(&size_of::<K>()).unwrap() + .checked_add(&size_of::<V>()).unwrap(); + assert!(size >= capacity.checked_mul(&size_of_bucket) + .expect("capacity overflow"), + "capacity overflow"); + + let buffer = allocate(size, malloc_alignment); + + let hashes = buffer.offset(hash_offset as int) as *mut u64; + + RawTable { + capacity: capacity, + size: 0, + hashes: hashes, + marker: marker::CovariantType, + } + } + + fn first_bucket_raw(&self) -> RawBucket<K, V> { + let hashes_size = self.capacity * size_of::<u64>(); + let keys_size = self.capacity * size_of::<K>(); + + let buffer = self.hashes as *mut u8; + let (keys_offset, vals_offset) = calculate_offsets(hashes_size, + keys_size, min_align_of::<K>(), + min_align_of::<V>()); + + unsafe { + RawBucket { + hash: self.hashes, + key: buffer.offset(keys_offset as int) as *mut K, + val: buffer.offset(vals_offset as int) as *mut V + } + } + } + + /// Creates a new raw table from a given capacity. All buckets are + /// initially empty. + #[allow(experimental)] + pub fn new(capacity: uint) -> RawTable<K, V> { + unsafe { + let ret = RawTable::new_uninitialized(capacity); + zero_memory(ret.hashes, capacity); + ret + } + } + + /// The hashtable's capacity, similar to a vector's. + pub fn capacity(&self) -> uint { + self.capacity + } + + /// The number of elements ever `put` in the hashtable, minus the number + /// of elements ever `take`n. + pub fn size(&self) -> uint { + self.size + } + + fn raw_buckets(&self) -> RawBuckets<K, V> { + RawBuckets { + raw: self.first_bucket_raw(), + hashes_end: unsafe { + self.hashes.offset(self.capacity as int) + } + } + } + + pub fn iter(&self) -> Entries<K, V> { + Entries { + iter: self.raw_buckets(), + elems_left: self.size(), + } + } + + pub fn mut_iter(&mut self) -> MutEntries<K, V> { + MutEntries { + iter: self.raw_buckets(), + elems_left: self.size(), + } + } + + pub fn move_iter(self) -> MoveEntries<K, V> { + MoveEntries { + iter: self.raw_buckets(), + table: self, + } + } + + /// Returns an iterator that copies out each entry. Used while the table + /// is being dropped. + unsafe fn rev_move_buckets(&mut self) -> RevMoveBuckets<K, V> { + let raw_bucket = self.first_bucket_raw(); + RevMoveBuckets { + raw: raw_bucket.offset(self.capacity as int), + hashes_end: raw_bucket.hash, + elems_left: self.size + } + } +} + +/// 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>, + hashes_end: *mut u64 +} + +impl<'a, K, V> Iterator<RawBucket<K, V>> for RawBuckets<'a, K, V> { + fn next(&mut self) -> Option<RawBucket<K, V>> { + while self.raw.hash != self.hashes_end { + unsafe { + // We are swapping out the pointer to a bucket and replacing + // it with the pointer to the next one. + let prev = ptr::replace(&mut self.raw, self.raw.offset(1)); + if *prev.hash != EMPTY_BUCKET { + return Some(prev); + } + } + } + + None + } +} + +/// An iterator that moves out buckets in reverse order. It leaves the table +/// in an an inconsistent state and should only be used for dropping +/// the table's remaining entries. It's used in the implementation of Drop. +struct RevMoveBuckets<'a, K, V> { + raw: RawBucket<K, V>, + hashes_end: *mut u64, + elems_left: uint +} + +impl<'a, K, V> Iterator<(K, V)> for RevMoveBuckets<'a, K, V> { + fn next(&mut self) -> Option<(K, V)> { + if self.elems_left == 0 { + return None; + } + + loop { + debug_assert!(self.raw.hash != self.hashes_end); + + unsafe { + self.raw = self.raw.offset(-1); + + if *self.raw.hash != EMPTY_BUCKET { + self.elems_left -= 1; + return Some(( + ptr::read(self.raw.key as *const K), + ptr::read(self.raw.val as *const V) + )); + } + } + } + } +} + +/// Iterator over shared references to entries in a table. +pub struct Entries<'a, K: 'a, V: 'a> { + iter: RawBuckets<'a, K, V>, + elems_left: uint, +} + +/// Iterator over mutable references to entries in a table. +pub struct MutEntries<'a, K: 'a, V: 'a> { + iter: RawBuckets<'a, K, V>, + elems_left: uint, +} + +/// Iterator over the entries in a table, consuming the table. +pub struct MoveEntries<K, V> { + table: RawTable<K, V>, + iter: RawBuckets<'static, K, V> +} + +impl<'a, K, V> Iterator<(&'a K, &'a V)> for Entries<'a, K, V> { + fn next(&mut self) -> Option<(&'a K, &'a V)> { + self.iter.next().map(|bucket| { + self.elems_left -= 1; + unsafe { + (&*bucket.key, + &*bucket.val) + } + }) + } + + fn size_hint(&self) -> (uint, Option<uint>) { + (self.elems_left, Some(self.elems_left)) + } +} + +impl<'a, K, V> Iterator<(&'a K, &'a mut V)> for MutEntries<'a, K, V> { + fn next(&mut self) -> Option<(&'a K, &'a mut V)> { + self.iter.next().map(|bucket| { + self.elems_left -= 1; + unsafe { + (&*bucket.key, + &mut *bucket.val) + } + }) + } + + fn size_hint(&self) -> (uint, Option<uint>) { + (self.elems_left, Some(self.elems_left)) + } +} + +impl<K, V> Iterator<(SafeHash, K, V)> for MoveEntries<K, V> { + fn next(&mut self) -> Option<(SafeHash, K, V)> { + self.iter.next().map(|bucket| { + self.table.size -= 1; + unsafe { + ( + SafeHash { + hash: *bucket.hash, + }, + ptr::read(bucket.key as *const K), + ptr::read(bucket.val as *const V) + ) + } + }) + } + + fn size_hint(&self) -> (uint, Option<uint>) { + let size = self.table.size(); + (size, Some(size)) + } +} + +impl<K: Clone, V: Clone> Clone for RawTable<K, V> { + fn clone(&self) -> RawTable<K, V> { + unsafe { + let mut new_ht = RawTable::new_uninitialized(self.capacity()); + + { + let cap = self.capacity(); + let mut new_buckets = Bucket::first(&mut new_ht); + let mut buckets = Bucket::first(self); + while buckets.index() != cap { + match buckets.peek() { + Full(full) => { + let (h, k, v) = { + let (k, v) = full.read(); + (full.hash(), k.clone(), v.clone()) + }; + *new_buckets.raw.hash = h.inspect(); + mem::overwrite(new_buckets.raw.key, k); + mem::overwrite(new_buckets.raw.val, v); + } + Empty(..) => { + *new_buckets.raw.hash = EMPTY_BUCKET; + } + } + new_buckets.next(); + buckets.next(); + } + }; + + new_ht.size = self.size(); + + new_ht + } + } +} + +#[unsafe_destructor] +impl<K, V> Drop for RawTable<K, V> { + fn drop(&mut self) { + if self.hashes.is_null() { + return; + } + // This is done in reverse because we've likely partially taken + // some elements out with `.move_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 { + for _ in self.rev_move_buckets() {} + } + + let hashes_size = self.capacity * size_of::<u64>(); + let keys_size = self.capacity * size_of::<K>(); + let vals_size = self.capacity * size_of::<V>(); + let (align, _, size) = calculate_allocation(hashes_size, min_align_of::<u64>(), + keys_size, min_align_of::<K>(), + vals_size, min_align_of::<V>()); + + unsafe { + deallocate(self.hashes as *mut u8, size, align); + // Remember how everything was allocated out of one buffer + // during initialization? We only need one call to free here. + } + } +} diff --git a/src/test/run-fail/hashmap-capacity-overflow.rs b/src/test/run-fail/hashmap-capacity-overflow.rs new file mode 100644 index 00000000000..f68b511d0aa --- /dev/null +++ b/src/test/run-fail/hashmap-capacity-overflow.rs @@ -0,0 +1,21 @@ +// 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. + +// error-pattern:capacity overflow + +use std::collections::hashmap::HashMap; +use std::uint; +use std::mem::size_of; + +fn main() { + let threshold = uint::MAX / size_of::<(u64, u64, u64)>(); + let mut h = HashMap::<u64, u64>::with_capacity(threshold + 100); + h.insert(0, 0); +} |