// Untested

class InfiniteGrid<T>
{

    public var cells : Hash<Array<T>>;

    public function new()
    {
        cells = new Hash();
    }

    public inline function posStr(x,y)
    {
        return Std.string(x)+"_"+Std.string(y);
    }
    
    public function add(x,y,val)
    {
        var pos = posStr(x,y);
        if (!cells.exists(pos))
        {
            cells.set(pos,new Array<T>());
        }
        var ar = cells.get(pos);
        ar.push(val);
    }
    
    public function remove(x,y,val)
    {
        var pos = posStr(x,y);
        if (cells.exists(pos))
        {
            var ar = cells.get(pos);
            var result = ar.remove(val);
            if (ar.length<1)
                cells.remove(pos);
            return result;
        }
        else return false;        
    }
    
    public function query(l,t,w,h)
    {
        var result = new Array<T>();
        var x = l;
        var y = t;
        while (x<l+w) { while (y<t+h)
        {
            var pos = posStr(x,y);
            if (cells.exists(pos))
            for (n in cells.get(pos))
                result.push(n);
            x++;
        } y++; x = l; }
        
        return result;
    }

}