You can probably simplify that task markedly using the Routeviews Project data.

http://www.routeviews.org/

Zonefiles are downloadable.

If you can get a comprehensive list of AWS/Amazon ASNs, you could also hit up the CIDR Report: http://www.cidr-report.org/as2.0/

The rabbit I haven't been able to pull from a hat yet is getting that list of ASNs without a fair bit of legwork.