| // Copyright (c) 2011, 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 util_implementation; |
| |
| class LinkIterator<T> implements Iterator<T> { |
| T _current; |
| Link<T> _link; |
| |
| LinkIterator(Link<T> this._link); |
| |
| T get current => _current; |
| |
| bool moveNext() { |
| if (_link.isEmpty) { |
| _current = null; |
| return false; |
| } |
| _current = _link.head; |
| _link = _link.tail; |
| return true; |
| } |
| } |
| |
| class LinkEntry<T> extends Link<T> { |
| final T head; |
| Link<T> tail; |
| |
| LinkEntry(T this.head, [Link<T> tail]) |
| : this.tail = ((tail == null) ? new Link<T>() : tail); |
| |
| Link<T> prepend(T element) { |
| // TODO(ahe): Use new Link<T>, but this cost 8% performance on VM. |
| return new LinkEntry<T>(element, this); |
| } |
| |
| void printOn(StringBuffer buffer, [separatedBy]) { |
| buffer.write(head); |
| if (separatedBy == null) separatedBy = ''; |
| for (Link link = tail; !link.isEmpty; link = link.tail) { |
| buffer.write(separatedBy); |
| buffer.write(link.head); |
| } |
| } |
| |
| String toString() { |
| StringBuffer buffer = new StringBuffer(); |
| buffer.write('[ '); |
| printOn(buffer, ', '); |
| buffer.write(' ]'); |
| return buffer.toString(); |
| } |
| |
| Link<T> reverse() { |
| Link<T> result = const Link(); |
| for (Link<T> link = this; !link.isEmpty; link = link.tail) { |
| result = result.prepend(link.head); |
| } |
| return result; |
| } |
| |
| Link<T> reversePrependAll(Link<T> from) { |
| Link<T> result; |
| for (result = this; !from.isEmpty; from = from.tail) { |
| result = result.prepend(from.head); |
| } |
| return result; |
| } |
| |
| Link<T> skip(int n) { |
| Link<T> link = this; |
| for (int i = 0 ; i < n ; i++) { |
| if (link.isEmpty) { |
| throw new RangeError('Index $n out of range'); |
| } |
| link = link.tail; |
| } |
| return link; |
| } |
| |
| bool get isEmpty => false; |
| |
| void forEach(void f(T element)) { |
| for (Link<T> link = this; !link.isEmpty; link = link.tail) { |
| f(link.head); |
| } |
| } |
| |
| bool operator ==(other) { |
| if (other is !Link<T>) return false; |
| Link<T> myElements = this; |
| while (!myElements.isEmpty && !other.isEmpty) { |
| if (myElements.head != other.head) { |
| return false; |
| } |
| myElements = myElements.tail; |
| other = other.tail; |
| } |
| return myElements.isEmpty && other.isEmpty; |
| } |
| |
| int get hashCode => throw new UnsupportedError('LinkEntry.hashCode'); |
| |
| int slowLength() => 1 + tail.slowLength(); |
| } |
| |
| class LinkBuilderImplementation<T> implements LinkBuilder<T> { |
| LinkEntry<T> head = null; |
| LinkEntry<T> lastLink = null; |
| int length = 0; |
| |
| LinkBuilderImplementation(); |
| |
| Link<T> toLink([Link<T> tail = const Link()]) { |
| if (head == null) return tail; |
| lastLink.tail = tail; |
| Link<T> link = head; |
| lastLink = null; |
| head = null; |
| return link; |
| } |
| |
| void addLast(T t) { |
| length++; |
| LinkEntry<T> entry = new LinkEntry<T>(t, null); |
| if (head == null) { |
| head = entry; |
| } else { |
| lastLink.tail = entry; |
| } |
| lastLink = entry; |
| } |
| |
| bool get isEmpty => length == 0; |
| } |