New implementation of {,Linked}Hash{Set,Map}.

sdk/lib/collection/hash_map.dart

+part of dart.collection;
+
+class HashMap<K, V> extends _HashTable<K> implements Map<K, V> {
+  static const int _INITIAL_CAPACITY = 8;
+  static const int _VALUE_INDEX = 1;
+
+  HashMap() : super(_INITIAL_CAPACITY);
+
+  factory HashMap.from(Map<K, V> other) {
+    return new HashMap<K, V>()..addAll(other);
+  }
+
+  int get _entrySize => 2;
+
+  V _value(int offset) => _table[offset + _VALUE_INDEX];
+  void _setValue(int offset, V value) { _table[offset + _VALUE_INDEX] = value; }
+
+  _copyEntry(List fromTable, int fromOffset, int toOffset) {
+    _table[toOffset + _VALUE_INDEX] = fromTable[fromOffset + _VALUE_INDEX];
+  }
+
+  bool containsKey(K key) {
+    return _get(key) >= 0;
+  }
+
+  bool containsValue(V value) {
+    for (int offset = 0; offset < _table.length; offset += _entrySize) {
+      if (!_isFree(_table[offset]) && _value(offset) == value) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  void addAll(Map<K, V> other) {
+    _ensureCapacity(other.length);
+    other.forEach((K key, V value) {
+      int offset = _put(key);
+      _setValue(offset, value);
+    });
+  }
+
+  V operator [](K key) {
+    int offset = _get(key);
+    if (offset >= 0) return _value(offset);
+    return null;
+  }
+
+  void operator []=(K key, V value) {
+    _ensureCapacity(1);
+    int offset = _put(key);
+    _setValue(offset, value);
+  }
+
+  V putIfAbsent(K key, V ifAbsent()) {
+    _ensureCapacity(1);
+    int offset = _probeForAdd(_hashCodeOf(key), key);
+    Object entry = _table[offset];
+    if (_isFree(entry)) {
+      V value = ifAbsent();
+      _setKey(offset, key);
+      _setValue(offset, value);
+      if (entry == null) {
+        _entryCount++;
+      } else {
+        assert(identical(entry, _TOMBSTONE));
+        _deletedCount--;
+      }
+      return value;
+    }
+    return _value(offset);
+  }
+
+  V remove(K key) {
+    int offset = _remove(key);
+    if (offset < 0) return null;
+    V oldValue = _value(offset);
+    _setValue(offset, null);
+    return oldValue;
+  }
+
+  void clear() {
+    _clear();
+  }
+
+  void forEach(void action (K key, V value)) {
+    int modificationCount = _modificationCount;
+    for (int offset = 0; offset < _table.length; offset += _entrySize) {
+      Object entry = _table[offset];
+      if (!_isFree(entry)) {
+        K key = entry;
+        V value = _value(offset);
+        action(key, value);
+        _checkModification(modificationCount);
+      }
+    }
+  }
+
+  Iterable<K> get keys => new _HashTableKeyIterable<K>(this);
+  Iterable<V> get values =>
+      new _HashTableValueIterable<V>(this, _VALUE_INDEX);
+
+  int get length => _elementCount;
+
+  bool get isEmpty => _elementCount == 0;
+
+  String toString() => Maps.mapToString(this);
+}