A cronjob to extract the contents of a zip file into a DB.

[eluser]gh0st[/eluser]
I've got a cronjob controller up and running fine (it just sends an email at the moment).

My situation is as follows;

1. Every night a new ZIP file, which contains a CSV file, which has 500,000+ rows will be uploaded to a specific directory outside of web root.
2. A cronjob runs a controller method (inaccessible via a web browser) that will:
a. Extract the contents of the ZIP file and then perform a few validation rules and then insert them into the Database.

But CI does not come with a UNZIP extractor, and I'm wondering is there a faster, easier way of handling such amounts of data.

Thanks