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

sdk/lib/collection/linked_hash_map.dart

+part of dart.collection;
+
+class LinkedHashMap<K, V> extends _LinkedHashTable<K> implements HashMap<K, V> {
+  static const int _INITIAL_CAPACITY = 8;
+  static const int _VALUE_INDEX = 3;
+  // ALias for easy access.
+  static const int _HEAD_OFFSET = _LinkedHashTable._HEAD_OFFSET;
+
+  int get _entrySize => 4;
+
+  LinkedHashMap() : super(_INITIAL_CAPACITY);
+
+  factory LinkedHashMap.from(Map<K, V> other) {
+    return new LinkedHashMap<K, V>()..addAll(other);
+  }
+
+  V _value(int offset) => _table[offset + _VALUE_INDEX];
+  void _setValue(int offset, V value) { _table[offset + _VALUE_INDEX] = value; }
+
+  _copyEntry(List oldTable, int fromOffset, int toOffset) {
+    _table[toOffset + _VALUE_INDEX] = oldTable[fromOffset + _VALUE_INDEX];
+  }
+
+  bool containsKey(K key) {
+    return _get(key) >= 0;
+  }
+
+  bool containsValue(V value) {
+    int modificationCount = _modificationCount;
+    for (int offset = _next(_HEAD_OFFSET);
+         offset != _HEAD_OFFSET;
+         offset = _next(offset)) {
+      if (_value(offset) == value) {
+        return true;
+      }
+      // The == call may modify the table.
+      _checkModification(modificationCount);
+    }
+    return false;
+  }
+
+  void addAll(Map<K, V> other) {
+    other.forEach((K key, V value) {
+      int offset = _put(key);
+      _setValue(offset, value);
+      _checkCapacity();
+    });
+  }
+
+  V operator [](K key) {
+    int offset = _get(key);
+    if (offset >= 0) return _value(offset);
+    return null;
+  }
+
+  void operator []=(K key, V value) {
+    int offset = _put(key);
+    _setValue(offset, value);
+    _checkCapacity();
+  }
+
+  V putIfAbsent(K key, V ifAbsent()) {
+    int offset = _probeForAdd(_hashCodeOf(key), key);
+    Object entry = _table[offset];
+    if (!_isFree(entry)) {
+      return _value(offset);
+    }
+    int modificationCount = _modificationCount;
+    V value = ifAbsent();
+    _checkModification(modificationCount);
+    if (entry == null) {
+      _entryCount++;
+      _checkCapacity();
+    } else {
+      assert(identical(entry, _TOMBSTONE));
+      _deletedCount--;
+    }
+    _setKey(offset, key);
+    _setValue(offset, value);
+    _linkLast(offset);
+    _recordModification();
+    return value;
+  }
+
+  V remove(K key) {
+    int offset = _remove(key);
+    if (offset < 0) return null;
+    Object oldValue = _value(offset);
+    _setValue(offset, null);
+    _checkCapacity();
+    return oldValue;
+  }
+
+  void clear() {
+    _clear();
+  }
+
+  void forEach(void action (K key, V value)) {
+    int modificationCount = _modificationCount;
+    for (int offset = _next(_HEAD_OFFSET);
+         offset != _HEAD_OFFSET;
+         offset = _next(offset)) {
+      action(_key(offset), _value(offset));
+      _checkModification(modificationCount);
+    }
+  }
+
+  Iterable<K> get keys => new _LinkedHashTableKeyIterable<K>(this);
+  Iterable<V> get values =>
+      new _LinkedHashTableValueIterable<V>(this, _VALUE_INDEX);
+
+  int get length => _elementCount;
+
+  bool get isEmpty => _elementCount == 0;
+
+  String toString() => Maps.mapToString(this);
+}