UZ_ITEMS_SLEEPER_SHIFT
#define UZ_ITEMS_SLEEPERS_MAX ((1 << (64 - UZ_ITEMS_SLEEPER_SHIFT)) - 1)
#define UZ_ITEMS_COUNT_MASK ((1LL << UZ_ITEMS_SLEEPER_SHIFT) - 1)
#define UZ_ITEMS_SLEEPERS(x) ((x) >> UZ_ITEMS_SLEEPER_SHIFT)
#define UZ_ITEMS_SLEEPER (1LL << UZ_ITEMS_SLEEPER_SHIFT)