Finding out if a given email address falls under blacklisted item

[phantom007]

I am developing a system where I have a textarea where I can add

1. email address (Eg: rob@example.com)
2. domain name (Eg: example.com)
3. subdomain name (Eg: subdomain.example.com)
4. wildcard (an astix *)

These items can either be separated by comma (,) or each item in a new line. These items will act as a list of blacklisted items. A user trying to signup using any of the above should not be allowed to signup. Here is how the system should behave:

1. rob@example.com will block rob@example.com

2. example.com will block {any_username}@example.com and also {any_username}@{any_subdomain}.example.com

3. subdomain.example.com will only block {any_username}@subdomain.example.com

4. * will block {any_username}@{any_domain} and also {any_username}@{any_subdomain}.{any_domain}

I am struggling to write a logic that could prevent a user to signup using the above logic.

Can someone please help?

[chorn]

what code have you made to try this on your own? maybe a translation to regex will help you. using regex as input format would be easy to verify and expand.