This is a carefully optimised slab allocator for userspace. It relies on
anonymous mmap(2) page allocations, or occassionally on posix_memalign(3)
for larger objects.
Bit-vectors are used to indicate whether the corresponding slots are free and that makes the allocations and deallocations very quick most of the time.
When allocating an object, a 64-bit unsigned integer is scanned for its first
set bit (this usually translates to a single BSF instruction on x86).
When deallocating an object, the location of the corresponding slab is quickly found by masking the passed object pointer with the alignment mask of the corresponding slab chain.
You may freely modify and redistribute the code as long as you preserve the link in the source code to this repository.