Split Protocol18 protocol into several classes

- Protocol18: Handles Vanilla packets
 - Protocol18Forge: Handles Forge packets
 - DataTypes: Handles packet field encoding/decoding
 - SocketWrapper: Handles encryption and basic R/W operations

This commit should not change anything for end users, only devs.
See also #704 for discussions about this.

MinecraftClient/Protocol/Handlers/SocketWrapper.cs

@@ -0,0 +1,116 @@
+using System;
+using System.Net.Sockets;
+using MinecraftClient.Crypto;
+
+namespace MinecraftClient.Protocol.Handlers
+{
+    /// <summary>
+    /// Wrapper for handling unencrypted & encrypted socket
+    /// </summary>
+    class SocketWrapper
+    {
+        TcpClient c;
+        IAesStream s;
+        bool encrypted = false;
+
+        /// <summary>
+        /// Initialize a new SocketWrapper
+        /// </summary>
+        /// <param name="client">TcpClient connected to the server</param>
+        public SocketWrapper(TcpClient client)
+        {
+            this.c = client;
+        }
+
+        /// <summary>
+        /// Check if the socket is still connected
+        /// </summary>
+        /// <returns>TRUE if still connected</returns>
+        /// <remarks>Silently dropped connection can only be detected by attempting to read/write data</remarks>
+        public bool IsConnected()
+        {
+            return c.Client != null && c.Connected;
+        }
+
+        /// <summary>
+        /// Check if the socket has data available to read
+        /// </summary>
+        /// <returns>TRUE if data is available to read</returns>
+        public bool HasDataAvailable()
+        {
+            return c.Client.Available > 0;
+        }
+
+        /// <summary>
+        /// Switch network reading/writing to an encrypted stream
+        /// </summary>
+        /// <param name="secretKey">AES secret key</param>
+        public void SwitchToEncrypted(byte[] secretKey)
+        {
+            if (encrypted)
+                throw new InvalidOperationException("Stream is already encrypted!?");
+            this.s = CryptoHandler.getAesStream(c.GetStream(), secretKey);
+            this.encrypted = true;
+        }
+
+        /// <summary>
+        /// Network reading method. Read bytes from the socket or encrypted socket.
+        /// </summary>
+        private void Receive(byte[] buffer, int start, int offset, SocketFlags f)
+        {
+            int read = 0;
+            while (read < offset)
+            {
+                if (encrypted)
+                {
+                    read += s.Read(buffer, start + read, offset - read);
+                }
+                else read += c.Client.Receive(buffer, start + read, offset - read, f);
+            }
+        }
+
+        /// <summary>
+        /// Read some data from the server.
+        /// </summary>
+        /// <param name="length">Amount of bytes to read</param>
+        /// <returns>The data read from the network as an array</returns>
+        public byte[] ReadDataRAW(int length)
+        {
+            if (length > 0)
+            {
+                byte[] cache = new byte[length];
+                Receive(cache, 0, length, SocketFlags.None);
+                return cache;
+            }
+            return new byte[] { };
+        }
+
+        /// <summary>
+        /// Send raw data to the server.
+        /// </summary>
+        /// <param name="buffer">data to send</param>
+        public void SendDataRAW(byte[] buffer)
+        {
+            if (encrypted)
+            {
+                s.Write(buffer, 0, buffer.Length);
+            }
+            else c.Client.Send(buffer);
+        }
+
+        /// <summary>
+        /// Disconnect from the server
+        /// </summary>
+        public void Disconnect()
+        {
+            try
+            {
+                c.Close();
+            }
+            catch (SocketException) { }
+            catch (System.IO.IOException) { }
+            catch (NullReferenceException) { }
+            catch (ObjectDisposedException) { }
+        }
+    }
+}