519     size_t free;

   519     size_t free;

   520     size_t free_high;

   520     size_t free_high;

   521     size_t free_low;

   521     size_t free_low;

   522   } _at_relocate_end;

   522   } _at_relocate_end;

   523 

   523 

   524   static size_t available(size_t used);

   526   static size_t available(size_t used);

   525   static size_t reserve(size_t used);

   527   static size_t reserve(size_t used);

   526   static size_t free(size_t used);

   528   static size_t free(size_t used);

   527 

   529 

   528 public:

   530 public: