class Queue is Sequence{
	data{_data}
	count{_count}

	construct new(){
		_data = []
		_count = 0
		_head = -1
	}

	clear(){
		_count = 0
		_head = -1
	}

	enqueue(value){
		_count = _count + 1
		_head = _head + 1
		if(_data.count >= _count){
			if(_head >= _data.count){
				_head = _head - _data.count
			}
			_data[_head] = value
		} else {
			_data.insert(_head, value)
		}
		return value
	}

	dequeue(){
		if(_count == 0) return null
		var res = peek()
		_count = _count - 1
		return res
	}

	peek(){
		if(_count == 0) return null
		var tail = _head - _count + 1
		if(tail < 0) tail = _data.count + tail
		return _data[tail]
	}

	empty(){_count == 0}

	iterate(iter){
		if(!iter) return _count > 0 ? 0 : false
		if(iter >= _count - 1) return false
		return iter + 1
	}

	iteratorValue(iter){
		var index = _head - _count + 1 + iter
		if(index < 0) index = _data.count + index
		return _data[index]
	}
}