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Ointers is a library for representing pointers where some bits have been stolen so that they may be used by the programmer for something else. In effect, it's a small amount of free storage
If we know that a pointer's address will always be aligned to A bytes where A > 1, we can steal log2(A-1) bytes. For an 8-byte aligned value, this provides a modest 3 bits.
If you have values aligned to some larger width, you could get even more. It's common in parallel programming to pad data to a cache line by increasing its alignment requirements in order eliminate false sharing. Because a cache line on amd64 or aarch64 is effectively 128 bytes thanks to prefetching, you can reclaim a respectable 7 extra bits.
If your data is aligned wider still, the sky is the limit, but you could get an incredible 24 bits if you have 16MB-aligned data! Remember that the only alignment rust knows about is what is declared for the type, so you must create a newtype wrapper to take full advantage of large alignment sizes.
Stealing bits from alignment is relatively innocuous, but we can only get the compiler to check it for you in dev mode as things stand in rust today.
