Nguyễn Thái Ngọc Duy <pclo...@gmail.com> writes: > These delta pointers always point to elements in the objects[] array > in packing_data struct. We can only hold maximum 4GB of those objects
4GB, as in "number of bytes"? Or "We can hold 4 billion or so of those objects"? > because the array length, nr_objects, is uint32_t. We could use > uint32_t indexes to address these elements instead of pointers. On > 64-bit architecture (8 bytes per pointer) this would save 4 bytes per > pointer. > > Convert these delta pointers to indexes. Since we need to handle NULL > pointers as well, the index is shifted by one [1]. > > [1] This means we can only index 2^32-2 objects even though nr_objects > could contain 2^32-1 objects. It should not be a problem in > practice because when we grow objects[], nr_alloc would probably > blow up long before nr_objects hits the wall.
