21.05.2016, 19:22
Short answer: you can't.
Long answer: it's too impractical. Either open each player's file and look for the e-mail address or keep one large list of e-mail addresses. Either way, the time to lookup an address increases as the number of registrations grows and therefore lag increases as well. One large list of addresses isn't a very good idea from a security standpoint either. Add to that that disk IO is inherently very slow and that dini is literally the worst file system ever, and you have a recipe for disaster.
Long answer: it's too impractical. Either open each player's file and look for the e-mail address or keep one large list of e-mail addresses. Either way, the time to lookup an address increases as the number of registrations grows and therefore lag increases as well. One large list of addresses isn't a very good idea from a security standpoint either. Add to that that disk IO is inherently very slow and that dini is literally the worst file system ever, and you have a recipe for disaster.