I've not personally used this extension, nor handled zip file uploads, so you'll have to do some experimentation on your own.
The zip functions seem easier and more intuitive to use, not to mention the class-based API doesn't seem to offer any way to directly read an archive without first unzipping it. But I can't tell whether or not the functions are an old and/or depreciated API.
Anyway, I imagine you'd do something like:
PHP Code:
$dir = zip_open('file');
$entry = zip_read($dir);
$clear = zip_entry_read($entry);