class ThreadSafe::Util::Adder

def add(x)
  if (current_cells = cells) || !cas_base_computed {|current_base| current_base + x}
    was_uncontended = true
    hash            = hash_code
    unless current_cells && (cell = current_cells.volatile_get_by_hash(hash)) && (was_uncontended = cell.cas_computed {|current_value| current_value + x})
      retry_update(x, hash, was_uncontended) {|current_value| current_value + x}
    end
  end
end