`Pow` for `Wrapping`/`Checked`

[BrettWitty]

It appears that neither of these types have the arithmetic for easily computing large powers (apart from shifts to emulate powers-of-two). Is this correct?

[tarcieri]

No, the Pow trait is not currently implemented for those wrappers

[mrdomino]

Fwiw I have a use case for this—actually, for a saturating Pow. I’m toying around with deterministic password generation from a regular language, so I’d like to be able to measure the size of the language and I’m fine with it topping out at like U256::MAX or something.

In my case I don’t even care about constant time, I just want to be able to zero my memory after I’m done with it.

[tarcieri]

We currently have little support for saturating arithmetic

[mrdomino]

Yeah ok; this is what I wound up sketching fwiw:

https://github.com/mrdomino/onepass/blob/d01f8eb289fc838aacf3115de9541b7315faf8d1/src/randexp/mod.rs#L108-L122

If something like that would be welcome as a PR under vartime I’d be happy to try and write it. Totally understand if not.