Re: Add support for base64url variant

[Stefan Monnier]

> I've used it for sharding into a blobstore on NTFS/SMB (two characters
> for first level, so tree width of 1024).  The key is indeed a hash
> (SHA512), so the probability of a collision would be low enough to just
> ignore the case (for only 512 wide tree), but it felt cleaner to encode
> via base32url instead.

Ah, I was assuming a hex representation of the hash.
In that case, using base32 is basically an optimization that shortens
the filename by ~20% [ Using base64 would make the hash a bit weaker and
shorten the filename by ~33% instead.  ]


        Stefan