The mapping of country code

where can I find the mapping from two letter country code to the corresponding country? what standard is this country code using? Is this two letter country code the same as the $http_cf_ipcountry that can be obtained in PHP? thanks a lot.

Hi there, I think it’s not currently available. please can you create feature request in our tracker: Issues · piwik/piwik · GitHub

The issue #11109 has been closed on github, so I think I should reply here about my use case.
I was trying to collect and analyze the user actions in my software, and I want to store where does each individual user come from. This info can be get using CF_COUNTRY when the client send data to the server. So, here comes the my problem : I don’t know the mapping, so I cannot convert CF_COUNTRY into the corresponding country codes in piwik.
Thanks a lot.