Implementing crc32c for AARCH64

[icrar]

Implementing crc32c for AARCH64

[rtobar]

Hi @ossdev07, I think there are two different points in your message, so I will address them separately.

Regarding the title of this ticket: our package doesn't currently support the optional ARMv8 crc32c instructions, mainly because we haven't had a use case that has pushed us to add it. However we'd be more than happy to accept such contribution, and make the package hardware-based implementation more generic rather than Intel-specific.

Regarding the selection of the software-based solution, this is mostly historical (you can see some discussion in #5). Changing this interface would be a breaking change (so it would mean an increase on the major version of the library), but I do agree that it would make sense to do it now that the library supports a good fallback software-based implementation. This point is completely separate from that of adding or not ARMv8 hardware-based crc32c support to the package though, so I'd rather we open a new issue to handle it separately.

[rtobar]

A first version of this support has been implemented on the current master branch. It works on Linux only at the moment, where a ~2-3x performance improvement can be seen in systems under test. A new release will be pushed out soon to PyPI with this and other improvements.