ArrayList

Tuesday, September 8, 2009
The compiler is getting to the point where I can start to sketch out some of the basic container classes. Here's what the ArrayList class looks like:

import tart.core.Math.max;

/** Array-backed list type. */
final class ArrayList[%ElementType] : List[ElementType] {
  private {
    var data:ElementType[];
    var _length:int;

    def grow(amount:int) {
      let nlength = self._length + amount;
      if data.length < nlength {
        let ndata = ElementType[](nlength + nlength / 2 + 16);
        ElementType[].copyElements(ndata, 0, data, 0, self._length);
        self.data = ndata;
      }

      self._length = nlength;
    }
  }

  def construct(data:ElementType...; initialCapacity:int = 0) {
    initialCapacity = max(initialCapacity, data.length);
    self.data = ElementType[](initialCapacity);
    ElementType[].copyElements(self.data, 0, data, 0, data.length);
    _length = data.length;
  }

  def construct(data:Array[ElementType], initialCapacity:int = 0) {
    initialCapacity = max(initialCapacity, data.length);
    self.data = ElementType[](initialCapacity);
    ElementType[].copyElements(self.data, 0, data, 0, data.length);
    _length = data.length;
  }

  def add(e:ElementType) {
  }

  def [index:int]:ElementType {
    get {
      Preconditions.checkIndex(index >= 0);
      Preconditions.checkIndex(index < _length);
      return data[index];
    }

    set {
      Preconditions.checkIndex(index >= 0);
      Preconditions.checkIndex(index < _length);
      data[index] = value;
    }
  }

  def length:int {
    get { return _length; }
  }

  def iterate -> Iterator[ElementType] {
    return ArrayListIterator(self);
  }

  private final class ArrayListIterator : Iterator[ElementType], HasLength {
    private var list:ArrayList;
    private var index:int;
   
    def construct(list:ArrayList) {
      self.list = list;
      self.index = 0;
    }
   
    def next -> ElementType or void {
      if (self.index < self.list.length) {
        return self.list.data[self.index++];
      } else {
        return;
      }
    }

    def length:long { get { return list.length; } }
  }
}

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