Provide way to produce truncated hashes about rust-multihash HOT 6 CLOSED

I have to admit I'm not fully convinced of the use case. I'm also cautious about having a bigger public API surface.

To conclude: There currently is a way to create Multihashes with a truncated hash via wrap(). We could introduce a convenient methods, once it shows up as a repeated pattern.

I'm closing this issue for now.

from rust-multihash.

I see that this can be implemented in terms of wrap, but I still think that it would be nice to have a dedicated method for this...

from rust-multihash.

There is no way to produce e.g. a multihash that uses Sha2_256 but only stores 16 bytes of hash data.

There is a way, you can call wrap().

Hence I don't know if there should be a truncate() method at all. In case there should be one, perhaps it would be one on digest creation time, something like digest_truncated(data, length).

from rust-multihash.

I don't think there is a benefit in doing this at digest creation time, since you have to generate the full hash anyway. Having discovered wrap, this is more a convenience method than a necessity. The question is how common this use case is, and if a convenience method is warranted.

from rust-multihash.

I don't think there is a benefit in doing this at digest creation time, since you have to generate the full hash anyway.

My thoughts came from the opposite direction. I don't think there is a benefit doing the truncation outside the digest creation as you would create a digest anyway.

from rust-multihash.

I can see cases where you already have a multihash from somewhere and want to truncate it, or you have two multihashes with different lengths and want to check whether they could refer to the same data.

But maybe let's leave this open and decide if and how to implement it once we have better use case examples. Should not take long.

from rust-multihash.