-> PortScanner added

Networking/PortScanner/InputChecker.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+
+namespace PortScanner
+{
+    static class InputChecker
+    {
+        // Check that a hostname string is valid
+        public static bool IsValidHostname(string hostname)
+        {
+            return hostname != "";
+        }
+
+        // Check that a port is valid - returns -1 if port is invalid
+        public static int ParsePort(string portString)
+        {
+            int port;
+
+            try
+            {
+                port = Int32.Parse(portString);
+            }
+            // If any exception occurs, the string was not a proper port
+            catch (Exception)
+            {
+                return -1;
+            }
+
+            if (port < 1 || port > 65535)
+            {
+                return -1;
+            }
+
+            return port;
+        }
+
+        // Check that timeout combobox user input is valid...
+        // Accepted formats: [time] ms, [time]ms, [time]
+        public static int ParseTimeout(string timeoutString)
+        {
+            // The regex that is used for matching the input against
+            var regex = new Regex(@"^\d*\s*(ms)?$");
+            
+            // Try matching the user input
+            if (!regex.IsMatch(timeoutString))
+            {
+                return -1;
+            }
+
+            // Slice off the "ms" part of the string
+            timeoutString = Regex.Match(timeoutString, @"\d+").Value;
+            int timeout = Int32.Parse(timeoutString);
+
+            // Doesn't work too well with a very short timeout period
+            if (timeout < 250 || timeout > 20000)
+            {
+                return -1;
+            }
+
+            return timeout;
+        }
+    }
+}