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Unified Diff: corelib/src/implementation/hash_map_set.dart

Issue 10890030: Move core and coreimpl from corelib/ to lib/core and lib/coreimpl. (Closed) Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart
Patch Set: Rebase. Created 8 years, 4 months ago
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Index: corelib/src/implementation/hash_map_set.dart
diff --git a/corelib/src/implementation/hash_map_set.dart b/corelib/src/implementation/hash_map_set.dart
deleted file mode 100644
index c3d45790e5f4af5bb17c6c62442fd8e765b925c0..0000000000000000000000000000000000000000
--- a/corelib/src/implementation/hash_map_set.dart
+++ /dev/null
@@ -1,454 +0,0 @@
-// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// Hash map implementation with open addressing and quadratic probing.
-class HashMapImplementation<K extends Hashable, V> implements HashMap<K, V> {
-
- // The [_keys] list contains the keys inserted in the map.
- // The [_keys] list must be a raw list because it
- // will contain both elements of type K, and the [_DELETED_KEY] of type
- // [_DeletedKeySentinel].
- // The alternative of declaring the [_keys] list as of type Object
- // does not work, because the HashSetIterator constructor would fail:
- // HashSetIterator(HashSet<E> set)
- // : _nextValidIndex = -1,
- // _entries = set_._backingMap._keys {
- // _advance();
- // }
- // With K being type int, for example, it would fail because
- // List<Object> is not assignable to type List<int> of entries.
- List _keys;
-
- // The values inserted in the map. For a filled entry index in this
- // list, there is always the corresponding key in the [keys_] list
- // at the same entry index.
- List<V> _values;
-
- // The load limit is the number of entries we allow until we double
- // the size of the lists.
- int _loadLimit;
-
- // The current number of entries in the map. Will never be greater
- // than [_loadLimit].
- int _numberOfEntries;
-
- // The current number of deleted entries in the map.
- int _numberOfDeleted;
-
- // The sentinel when a key is deleted from the map.
- static final _DeletedKeySentinel _DELETED_KEY = const _DeletedKeySentinel();
-
- // The initial capacity of a hash map.
- static final int _INITIAL_CAPACITY = 8; // must be power of 2
-
- HashMapImplementation() {
- _numberOfEntries = 0;
- _numberOfDeleted = 0;
- _loadLimit = _computeLoadLimit(_INITIAL_CAPACITY);
- _keys = new List(_INITIAL_CAPACITY);
- _values = new List<V>(_INITIAL_CAPACITY);
- }
-
- factory HashMapImplementation.from(Map<K, V> other) {
- Map<K, V> result = new HashMapImplementation<K, V>();
- other.forEach((K key, V value) { result[key] = value; });
- return result;
- }
-
- static int _computeLoadLimit(int capacity) {
- return (capacity * 3) ~/ 4;
- }
-
- static int _firstProbe(int hashCode, int length) {
- return hashCode & (length - 1);
- }
-
- static int _nextProbe(int currentProbe, int numberOfProbes, int length) {
- return (currentProbe + numberOfProbes) & (length - 1);
- }
-
- int _probeForAdding(K key) {
- int hash = _firstProbe(key.hashCode(), _keys.length);
- int numberOfProbes = 1;
- int initialHash = hash;
- // insertionIndex points to a slot where a key was deleted.
- int insertionIndex = -1;
- while (true) {
- // [existingKey] can be either of type [K] or [_DeletedKeySentinel].
- Object existingKey = _keys[hash];
- if (existingKey === null) {
- // We are sure the key is not already in the set.
- // If the current slot is empty and we didn't find any
- // insertion slot before, return this slot.
- if (insertionIndex < 0) return hash;
- // If we did find an insertion slot before, return it.
- return insertionIndex;
- } else if (existingKey == key) {
- // The key is already in the map. Return its slot.
- return hash;
- } else if ((insertionIndex < 0) && (_DELETED_KEY === existingKey)) {
- // The slot contains a deleted element. Because previous calls to this
- // method may not have had this slot deleted, we must continue iterate
- // to find if there is a slot with the given key.
- insertionIndex = hash;
- }
-
- // We did not find an insertion slot. Look at the next one.
- hash = _nextProbe(hash, numberOfProbes++, _keys.length);
- // _ensureCapacity has guaranteed the following cannot happen.
- // assert(hash != initialHash);
- }
- }
-
- int _probeForLookup(K key) {
- int hash = _firstProbe(key.hashCode(), _keys.length);
- int numberOfProbes = 1;
- int initialHash = hash;
- while (true) {
- // [existingKey] can be either of type [K] or [_DeletedKeySentinel].
- Object existingKey = _keys[hash];
- // If the slot does not contain anything (in particular, it does not
- // contain a deleted key), we know the key is not in the map.
- if (existingKey === null) return -1;
- // The key is in the map, return its index.
- if (existingKey == key) return hash;
- // Go to the next probe.
- hash = _nextProbe(hash, numberOfProbes++, _keys.length);
- // _ensureCapacity has guaranteed the following cannot happen.
- // assert(hash != initialHash);
- }
- }
-
- void _ensureCapacity() {
- int newNumberOfEntries = _numberOfEntries + 1;
- // Test if adding an element will reach the load limit.
- if (newNumberOfEntries >= _loadLimit) {
- _grow(_keys.length * 2);
- return;
- }
-
- // Make sure that we don't have poor performance when a map
- // contains lots of deleted entries: we _grow if
- // there are more deleted entried than free entries.
- int capacity = _keys.length;
- int numberOfFreeOrDeleted = capacity - newNumberOfEntries;
- int numberOfFree = numberOfFreeOrDeleted - _numberOfDeleted;
- // assert(numberOfFree > 0);
- if (_numberOfDeleted > numberOfFree) {
- _grow(_keys.length);
- }
- }
-
- static bool _isPowerOfTwo(int x) {
- return ((x & (x - 1)) == 0);
- }
-
- void _grow(int newCapacity) {
- assert(_isPowerOfTwo(newCapacity));
- int capacity = _keys.length;
- _loadLimit = _computeLoadLimit(newCapacity);
- List oldKeys = _keys;
- List<V> oldValues = _values;
- _keys = new List(newCapacity);
- _values = new List<V>(newCapacity);
- for (int i = 0; i < capacity; i++) {
- // [key] can be either of type [K] or [_DeletedKeySentinel].
- Object key = oldKeys[i];
- // If there is no key, we don't need to deal with the current slot.
- if (key === null || key === _DELETED_KEY) {
- continue;
- }
- V value = oldValues[i];
- // Insert the {key, value} pair in their new slot.
- int newIndex = _probeForAdding(key);
- _keys[newIndex] = key;
- _values[newIndex] = value;
- }
- _numberOfDeleted = 0;
- }
-
- void clear() {
- _numberOfEntries = 0;
- _numberOfDeleted = 0;
- int length = _keys.length;
- for (int i = 0; i < length; i++) {
- _keys[i] = null;
- _values[i] = null;
- }
- }
-
- void operator []=(K key, V value) {
- _ensureCapacity();
- int index = _probeForAdding(key);
- if ((_keys[index] === null) || (_keys[index] === _DELETED_KEY)) {
- _numberOfEntries++;
- }
- _keys[index] = key;
- _values[index] = value;
- }
-
- V operator [](K key) {
- int index = _probeForLookup(key);
- if (index < 0) return null;
- return _values[index];
- }
-
- V putIfAbsent(K key, V ifAbsent()) {
- int index = _probeForLookup(key);
- if (index >=0) return _values[index];
-
- V value = ifAbsent();
- this[key] = value;
- return value;
- }
-
- V remove(K key) {
- int index = _probeForLookup(key);
- if (index >= 0) {
- _numberOfEntries--;
- V value = _values[index];
- _values[index] = null;
- // Set the key to the sentinel to not break the probing chain.
- _keys[index] = _DELETED_KEY;
- _numberOfDeleted++;
- return value;
- }
- return null;
- }
-
- bool isEmpty() {
- return _numberOfEntries == 0;
- }
-
- int get length() {
- return _numberOfEntries;
- }
-
- void forEach(void f(K key, V value)) {
- int length = _keys.length;
- for (int i = 0; i < length; i++) {
- var key = _keys[i];
- if ((key !== null) && (key !== _DELETED_KEY)) {
- f(key, _values[i]);
- }
- }
- }
-
-
- Collection<K> getKeys() {
- List<K> list = new List<K>(length);
- int i = 0;
- forEach(void _(K key, V value) {
- list[i++] = key;
- });
- return list;
- }
-
- Collection<V> getValues() {
- List<V> list = new List<V>(length);
- int i = 0;
- forEach(void _(K key, V value) {
- list[i++] = value;
- });
- return list;
- }
-
- bool containsKey(K key) {
- return (_probeForLookup(key) != -1);
- }
-
- bool containsValue(V value) {
- int length = _values.length;
- for (int i = 0; i < length; i++) {
- var key = _keys[i];
- if ((key !== null) && (key !== _DELETED_KEY)) {
- if (_values[i] == value) return true;
- }
- }
- return false;
- }
-
- String toString() {
- return Maps.mapToString(this);
- }
-}
-
-class HashSetImplementation<E extends Hashable> implements HashSet<E> {
-
- HashSetImplementation() {
- _backingMap = new HashMapImplementation<E, E>();
- }
-
- factory HashSetImplementation.from(Iterable<E> other) {
- Set<E> set = new HashSetImplementation<E>();
- for (final e in other) {
- set.add(e);
- }
- return set;
- }
-
- void clear() {
- _backingMap.clear();
- }
-
- void add(E value) {
- _backingMap[value] = value;
- }
-
- bool contains(E value) {
- return _backingMap.containsKey(value);
- }
-
- bool remove(E value) {
- if (!_backingMap.containsKey(value)) return false;
- _backingMap.remove(value);
- return true;
- }
-
- void addAll(Collection<E> collection) {
- collection.forEach(void _(E value) {
- add(value);
- });
- }
-
- Set<E> intersection(Collection<E> collection) {
- Set<E> result = new Set<E>();
- collection.forEach(void _(E value) {
- if (contains(value)) result.add(value);
- });
- return result;
- }
-
- bool isSubsetOf(Collection<E> other) {
- return new Set<E>.from(other).containsAll(this);
- }
-
- void removeAll(Collection<E> collection) {
- collection.forEach(void _(E value) {
- remove(value);
- });
- }
-
- bool containsAll(Collection<E> collection) {
- return collection.every(bool _(E value) {
- return contains(value);
- });
- }
-
- void forEach(void f(E element)) {
- _backingMap.forEach(void _(E key, E value) {
- f(key);
- });
- }
-
- Set map(f(E element)) {
- Set result = new Set();
- _backingMap.forEach(void _(E key, E value) {
- result.add(f(key));
- });
- return result;
- }
-
- Dynamic reduce(Dynamic initialValue,
- Dynamic combine(Dynamic previousValue, E element)) {
- return Collections.reduce(this, initialValue, combine);
- }
-
- Set<E> filter(bool f(E element)) {
- Set<E> result = new Set<E>();
- _backingMap.forEach(void _(E key, E value) {
- if (f(key)) result.add(key);
- });
- return result;
- }
-
- bool every(bool f(E element)) {
- Collection<E> keys = _backingMap.getKeys();
- return keys.every(f);
- }
-
- bool some(bool f(E element)) {
- Collection<E> keys = _backingMap.getKeys();
- return keys.some(f);
- }
-
- bool isEmpty() {
- return _backingMap.isEmpty();
- }
-
- int get length() {
- return _backingMap.length;
- }
-
- Iterator<E> iterator() {
- return new HashSetIterator<E>(this);
- }
-
- String toString() {
- return Collections.collectionToString(this);
- }
-
- // The map backing this set. The associations in this map are all
- // of the form element -> element. If a value is not in the map,
- // then it is not in the set.
- HashMapImplementation<E, E> _backingMap;
-}
-
-class HashSetIterator<E> implements Iterator<E> {
-
- // TODO(4504458): Replace set_ with set.
- HashSetIterator(HashSetImplementation<E> set_)
- : _nextValidIndex = -1,
- _entries = set_._backingMap._keys {
- _advance();
- }
-
- bool hasNext() {
- if (_nextValidIndex >= _entries.length) return false;
- if (_entries[_nextValidIndex] === HashMapImplementation._DELETED_KEY) {
- // This happens in case the set was modified in the meantime.
- // A modification on the set may make this iterator misbehave,
- // but we should never return the sentinel.
- _advance();
- }
- return _nextValidIndex < _entries.length;
- }
-
- E next() {
- if (!hasNext()) {
- throw const NoMoreElementsException();
- }
- E res = _entries[_nextValidIndex];
- _advance();
- return res;
- }
-
- void _advance() {
- int length = _entries.length;
- var entry;
- final deletedKey = HashMapImplementation._DELETED_KEY;
- do {
- if (++_nextValidIndex >= length) break;
- entry = _entries[_nextValidIndex];
- } while ((entry === null) || (entry === deletedKey));
- }
-
- // The entries in the set. May contain null or the sentinel value.
- List<E> _entries;
-
- // The next valid index in [_entries] or the length of [entries_].
- // If it is the length of [_entries], calling [hasNext] on the
- // iterator will return false.
- int _nextValidIndex;
-}
-
-/**
- * A singleton sentinel used to represent when a key is deleted from the map.
- * We can't use [: const Object() :] as a sentinel because it would end up
- * canonicalized and then we cannot distinguish the deleted key from the
- * canonicalized [: Object() :].
- */
-class _DeletedKeySentinel {
- const _DeletedKeySentinel();
-}
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