Add C timestamp implementation; need to fix tests

nirosys commented 6 months ago

Issue #, if available: n/a

Description of changes: This PR adds a C implementation for Timestamps, rather than using the python implementation found in amazon.ion.core.

Drafting because there are still a couple of things I need to address:

The write side, I made some changes to the way the timestamp components are stored, and did not update for writing. I'm in the process of fixing that.
String representation includes some trailing zeroes if the subsecond precision is less than microseconds.

Had some issues locally with py.test and what looked like incredibly large decimals, but I'm not sure if that's due to write-side issue above.

I'll add a more detailed description of the changes later today.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

nirosys commented 6 months ago

Will address the conflict, with incoming fixes as well.

nirosys commented 3 months ago

Closing this for now. Improvements were made with #337.

amazon-ion / ion-python