sclass SynchronizedLongBuffer is ILongBuffer {

  long[] data;

  int size;

  *() {}

  *(int size) { if (size != 0) data = new long[size]; }

  *(Iterable<Long> l) {

    if (l cast Cl) allocate(l.size());

    addAll(l);

  }

  public synchronized void add(long i) {

    if (size >= lLongArray(data)) {

      data = resizeLongArray(data, Math.max(1, toInt(Math.min(maximumSafeArraySize(), lLongArray(data)*2L))));

      if (size >= data.length) fail("LongBuffer too large: " + size);

    }

    data[size++] = i;

  }

  synchronized void allocate(int n) {

    data = resizeLongArray(data, max(n, size()));

  }

  public synchronized void addAll(Iterable<Long> l) {

    if (l != null) for (long i : l) add(i);

  }

  public synchronized long[] toArray() {

    ret size == 0 ? null : resizeLongArray(data, size);

  }

  synchronized L<Long> toList() {

    ret longArrayToList(data, 0, size);

  }

  public synchronized L<Long> asVirtualList() {

    ret listFromFunction get(size);

  }

  synchronized void reset { size = 0; }

  void clear { reset(); }

  synchronized public int size() { ret size; }

  public synchronized bool isEmpty() { ret size == 0; }

  public synchronized long get(int idx) {

    if (idx >= size) fail("Index out of range: " + idx + "/" + size);

    ret data[idx];

  }

  synchronized void set(int idx, long value) {

    if (idx >= size) fail("Index out of range: " + idx + "/" + size);

    data[idx] = value;

  }

  public synchronized long popLast() {

    if (size == 0) fail("empty buffer");

    ret data[--size];

  }

  public synchronized long last() { ret data[size-1]; }

  synchronized long nextToLast() { ret data[size-2]; }

  toString { ret squareBracket(joinWithSpace(toList())); }

  public synchronized Iterator<Long> iterator() {

    ret new ItIt<Long> {

      int i = 0;

      public bool hasNext() { ret i < size(); }

      public Long next() {

        synchronized(SynchronizedLongBuffer.this) {

          if (!hasNext()) fail("Index out of bounds: " + i);

          ret data[i++];

        }

      }

    };

  }

  public synchronized void trimToSize {

    data = resizeLongArray(data, size);

  }

  synchronized void remove(int idx) {

    arraycopy(data, idx+1, data, idx, size-1-idx);

    --size;

  }

  // don't rely on return value if buffer is empty

  public synchronized long poll() { 

    ret size == 0 ? -1 : data[--size];

  }

  public synchronized void insertAt(int idx, long[] l) {

    int n = l(l);

    if (n == 0) ret;

    long[] newData = new[size+n];

    arraycopy(data, 0, newData, 0, idx);

    arraycopy(l, 0, newData, idx, n);

    arraycopy(data, idx, newData, idx+n, size-idx);

    data = newData;

    size = newData.length;

  }

  public void integrityCheck {

    assertTrue("Size positive", size >= 0);

    assertTrue("Data length", l(data) >= size);

  }

}