Changed SupportedAlgorithms class to Registry Design Pattern.

[arabasso]

Hello!

I am sending this modification to provide the possibility to alter the hashing and checksum algorithms of Octodiff (this will allow to use mainly more performative hashing algorithms).

[CLAassistant]

All committers have signed the CLA.

[droyad]

@arabasso Sorry, this slipped under the radar as the CLA was not signed. This looks good to me and I'm happy to merge it once the CLA is signed.

I couldn't think of a good way to keep this backwards compatible, so we'll need to bump the major

[arabasso]

Hello! Sorry, just now I became aware of this CLA... Anyway, about the modification, I made it so that the code was fully backwards compatible.

[droyad]

@arabasso Thanks. It's compile time compatible, but I'm not sure it's runtime compatible. I might just check on that.

[droyad]

Yeh I get a System.TypeLoadException: Could not load type 'Checksum' from assembly 'Octodiff when I drop the the updated DLL into it. Only a problem if it on the crazy chance someone is calling those methods from outside.

[arabasso]

Yes, it is not runtime compatible because additional classes and interfaces have been created. Anyone who wants to use this version of the library will have to recompile the project that uses it.

[arabasso]

Also, it would be interesting to use the xxHash algorithm instead of SHA1 (SHA1 has an average speed of 0.28 GB/s, while xxHash has 5.4 GB/s).

https://cyan4973.github.io/xxHash/