objective-c 이메일 주소 검증하기

- (BOOL)checkEmail:(NSString *)email
{
    const char *tmp = [email cStringUsingEncoding:NSUTF8StringEncoding];
    if (email.length != strlen(tmp))
    {
        return NO;
    }
    
    NSString *check = @"([0-9a-zA-Z_-]+)@([0-9a-zA-Z_-]+)(\\.[0-9a-zA-Z_-]+){1,2}";
    NSRange match = [email rangeOfString:check options:NSRegularExpressionSearch];
    if (NSNotFound == match.location)
    {
        return NO;
    }
    return YES;
}