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

sdk/lib/collection/linked_hash_set.dart

Index: sdk/lib/collection/linked_hash_set.dart
diff --git a/sdk/lib/collection/linked_hash_set.dart b/sdk/lib/collection/linked_hash_set.dart
new file mode 100644
index 0000000000000000000000000000000000000000..e72493aad57173be1f21d833f0fa395d68b88a95
--- /dev/null
+++ b/sdk/lib/collection/linked_hash_set.dart
@@ -0,0 +1,157 @@
+// Copyright (c) 2013, 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.
+
+part of dart.collection;
+
+class LinkedHashSet<E> extends Collection<E> implements Set<E> {
+  static const int _INITIAL_CAPACITY = 8;
+  _LinkedHashTable<E> _table;
+
+  LinkedHashSet() : _table = new _LinkedHashTable(_INITIAL_CAPACITY) {
+    _table._container = this;
+  }
+
+  factory LinkedHashSet.from(Iterable<E> iterable) {
+    return new LinkedHashSet<E>()..addAll(iterable);
+  }
+
+  // Iterable.
+  Iterator<E> get iterator => new _LinkedHashTableKeyIterator<E>(_table);
+
+  void forEach(void action(E element)) {
+    int offset = _table._next(_LinkedHashTable._HEAD_OFFSET);
+    int modificationCount = _table._modificationCount;
+    while (offset != _LinkedHashTable._HEAD_OFFSET) {
+      E key = _table._key(offset);
+      action(key);
+      _table._checkModification(modificationCount);
+      offset = _table._next(offset);
+    }
+  }
+
+  bool get isEmpty => _table._elementCount == 0;
+
+  bool contains(Object object) => _table._get(object) >= 0;
+
+  E get first {
+    int firstOffset = _table._next(_LinkedHashTable._HEAD_OFFSET);
+    if (firstOffset == _LinkedHashTable._HEAD_OFFSET) {
+      throw new StateError("No elements");
+    }
+    return _table._key(firstOffset);
+  }
+
+  E get last {
+    int lastOffset = _table._prev(_LinkedHashTable._HEAD_OFFSET);
+    if (lastOffset == _LinkedHashTable._HEAD_OFFSET) {
+      throw new StateError("No elements");
+    }
+    return _table._key(lastOffset);
+  }
+
+  E get single {
+    int firstOffset = _table._next(_LinkedHashTable._HEAD_OFFSET);
+    if (firstOffset == _LinkedHashTable._HEAD_OFFSET) {
+      throw new StateError("No elements");
+    }
+    int lastOffset = _table._prev(_LinkedHashTable._HEAD_OFFSET);
+    if (lastOffset != firstOffset) {
+      throw new StateError("Too many elements");
+    }
+    return _table._key(firstOffset);
+  }
+
+  // Collection.
+  void add(E element) {
+    _table._put(element);
+    _table._checkCapacity();
+  }
+
+  void addAll(Iterable<E> objects) {
+    for (E object in objects) {
+      _table._put(object);
+      _table._checkCapacity();
+    }
+  }
+
+  bool remove(Object object) {
+    int offset = _table._remove(object);
+    if (offset >= 0) {
+      _table._checkCapacity();
+      return true;
+    }
+    return false;
+  }
+
+  void removeAll(Iterable objectsToRemove) {
+    for (Object object in objectsToRemove) {
+      _table._remove(object);
+      _table._checkCapacity();
+    }
+  }
+
+  void retainAll(Iterable objectsToRemove) {
+    IterableMixinWorkaround.retainAll(this, objectsToRemove);
+  }
+
+  void _filterMatching(bool test(E element), bool removeMatching) {
+    int entrySize = _table._entrySize;
+    int length = _table._table.length;
+    int offset = _table._next(_LinkedHashTable._HEAD_OFFSET);
+    while (offset != _LinkedHashTable._HEAD_OFFSET) {
+      E key = _table._key(offset);
+      int nextOffset = _table._next(offset);
+      int modificationCount = _table._modificationCount;
+      bool shouldRemove = (removeMatching == test(key));
+      _table._checkModification(modificationCount);
+      if (shouldRemove) {
+        _table._deleteEntry(offset);
+      }
+      offset = nextOffset;
+    }
+    _table._checkCapacity();
+  }
+
+  void removeMatching(bool test(E element)) {
+    _filterMatching(test, true);
+  }
+
+  void retainMatching(bool test(E element)) {
+    _filterMatching(test, false);
+  }
+
+  void clear() {
+    _table._clear();
+  }
+
+  // Set.
+  bool isSubsetOf(Collection<E> collection) {
+    Set otherSet;
+    if (collection is Set) {
+      otherSet = collection;
+    } else {
+      otherSet = collection.toSet();
+    }
+    return otherSet.containsAll(this);
+  }
+
+  bool containsAll(Collection<E> collection) {
+    for (E element in collection) {
+      if (!this.contains(element)) return false;
+    }
+    return true;
+  }
+
+  Set<E> intersection(Collection<E> other) {
+    Set<E> result = new LinkedHashSet<E>();
+    for (E element in other) {
+      if (this.contains(element)) {
+        result.add(element);
+      }
+    }
+    return result;
+  }
+
+  String toString() => Collections.collectionToString(this);
+}