sclass IntBuffer implements Iterable<Int> {
  int[] data;
  int size;
  
  *() {}
  *(int size) { if (size != 0) data = new int[size]; }
  *(Iterable<Int> l) { this(l(l)); addAll(l); }
  
  void add(int i) {
    if (size >= lIntArray(data))
      data = resizeIntArray(data, Math.max(1, lIntArray(data)*2));
    data[size++] = i;
  }
  
  void addAll(Iterable<Int> l) {
    if (l != null) for (int i : l) add(i);
  }
  
  int[] toArray() {
    ret size == 0 ? null : resizeIntArray(data, size);
  }
  
  L<Int> toList() {
    ret intArrayToList(data, 0, size);
  }

  L<Int> asVirtualList() {
    ret listFromFunction get(size);
  }
  
  void reset { size = 0; }
  void clear { reset(); }
  
  int size() { ret size; }
  bool isEmpty() { ret size == 0; }
  
  int get(int idx) {
    if (idx >= size) fail("Index out of range: " + idx + "/" + size);
    ret data[idx];
  }
  
  void set(int idx, int value) {
    if (idx >= size) fail("Index out of range: " + idx + "/" + size);
    data[idx] = value;
  }
  
  int popLast() {
    if (size == 0) fail("empty buffer");
    ret data[--size];
  }
  
  int last() { ret data[size-1]; }
  int nextToLast() { ret data[size-2]; }
  
  toString { ret squareBracket(joinWithSpace(toList())); }
  
  public Iterator<Int> iterator() {
    ret new ItIt<Int> {
      int i = 0;
      
      public bool hasNext() { ret i < size; }
      public Int next() {
        if (!hasNext()) fail("Index out of bounds: " + i);
        ret data[i++];
      }
    };
  }
}