The member variable arenaSize contains the size of the Arena storage file in bytes. The member variable masterWindow is used for two purposes. First, it serves as the parent of all the other Windows in the Arena. Second, it maps the initial block of the storage file where the ArenaInitialBlock object (See Section 3.3.5) is placed.
The member variable windowTable is an instance of the SortedPointerTable template class as the inventory of all the Windows for objects. The member variable freeList contains the offset of one of the free chunks, which are doubly linked like a ring. The member variable topChunk contains the offset of the special free chunk located at the tail of the Arena. The chunk is not linked with the freeList.