--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/com/glavsoft/rfb/protocol/state/HandshakeState.java	Tue Jul 03 13:20:49 2012 +0900
@@ -0,0 +1,96 @@
+// Copyright (C) 2010, 2011 GlavSoft LLC.
+// All rights reserved.
+//
+//-------------------------------------------------------------------------
+// This file is part of the TightVNC software.  Please visit our Web site:
+//
+//                       http://www.tightvnc.com/
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, write to the Free Software Foundation, Inc.,
+// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+//-------------------------------------------------------------------------
+//
+
+package com.glavsoft.rfb.protocol.state;
+
+import com.glavsoft.exceptions.TransportException;
+import com.glavsoft.exceptions.UnsupportedProtocolVersionException;
+import com.glavsoft.rfb.protocol.ProtocolContext;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class HandshakeState extends ProtocolState {
+
+	public static final String PROTOCOL_VERSION_3_8 = "3.8";
+	public static final String PROTOCOL_VERSION_3_7 = "3.7";
+	public static final String PROTOCOL_VERSION_3_3 = "3.3";
+	private static final int PROTOCOL_STRING_LENGTH = 12;
+	private static final String PROTOCOL_STRING_REGEXP = "^RFB (\\d\\d\\d).(\\d\\d\\d)\n$";
+
+	private static final int MIN_SUPPORTED_VERSION_MAJOR = 3;
+	private static final int MIN_SUPPORTED_VERSION_MINOR = 3;
+
+	private static final int MAX_SUPPORTED_VERSION_MAJOR = 3;
+	private static final int MAX_SUPPORTED_VERSION_MINOR = 8;
+
+	public HandshakeState(ProtocolContext context) {
+		super(context);
+	}
+
+	@Override
+	public boolean next() throws UnsupportedProtocolVersionException, TransportException {
+		handshake();
+		return true;
+	}
+
+	private void handshake() throws TransportException, UnsupportedProtocolVersionException {
+		String protocolString = reader.readString(PROTOCOL_STRING_LENGTH);
+		logger.info("Server sent protocol string: " + protocolString.substring(0, protocolString.length() - 1));
+		Pattern pattern = Pattern.compile(PROTOCOL_STRING_REGEXP);
+		final Matcher matcher = pattern.matcher(protocolString);
+		if ( ! matcher.matches())
+			throw new UnsupportedProtocolVersionException(
+					"Unsupported protocol version: " + protocolString);
+		int major = Integer.parseInt(matcher.group(1));
+		int minor = Integer.parseInt(matcher.group(2));
+		if (major < MIN_SUPPORTED_VERSION_MAJOR ||
+				MIN_SUPPORTED_VERSION_MAJOR == major && minor <MIN_SUPPORTED_VERSION_MINOR)
+			throw new UnsupportedProtocolVersionException(
+					"Unsupported protocol version: " + major + "." + minor);
+		if (major > MAX_SUPPORTED_VERSION_MAJOR) {
+			major = MAX_SUPPORTED_VERSION_MAJOR;
+			minor = MAX_SUPPORTED_VERSION_MINOR;
+		}
+
+		if (minor >= MIN_SUPPORTED_VERSION_MINOR && minor < 7) {
+			changeStateTo(new SecurityType33State(context));
+			context.getSettings().setProtocolVersion(PROTOCOL_VERSION_3_3);
+			minor = 3;
+		} else if (7 == minor) {
+			changeStateTo(new SecurityType37State(context));
+			context.getSettings().setProtocolVersion(PROTOCOL_VERSION_3_7);
+			minor = 7;
+		} else if (minor >= MAX_SUPPORTED_VERSION_MINOR) {
+			changeStateTo(new SecurityTypeState(context));
+			context.getSettings().setProtocolVersion(PROTOCOL_VERSION_3_8);
+			minor = 8;
+		} else
+			throw new UnsupportedProtocolVersionException(
+					"Unsupported protocol version: " + protocolString);
+		writer.write(("RFB 00" + major + ".00" + minor + "\n").getBytes());
+		logger.info("Set protocol version to: " + context.getSettings().getProtocolVersion());
+	}
+
+}