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Panda Core is the core module of Panda Framework, it contains commonly used utility classes similar to apache-commons.

There is a newer version: 1.8.0

package panda.net.telnet;

/***
 * Implements the telnet window size option RFC 1073.
 ***/
public class WindowSizeOptionHandler extends TelnetOptionHandler {
	/***
	 * Horizontal Size
	 ***/
	private int m_nWidth = 80;

	/***
	 * Vertical Size
	 ***/
	private int m_nHeight = 24;

	/***
	 * Window size option
	 ***/
	protected static final int WINDOW_SIZE = 31;

	/***
	 * Constructor for the WindowSizeOptionHandler. Allows defining desired initial setting for
	 * local/remote activation of this option and behaviour in case a local/remote activation
	 * request for this option is received.
	 * 
	 * 
	 * @param nWidth - Window width.
	 * @param nHeight - Window Height
	 * @param initlocal - if set to true, a WILL is sent upon connection.
	 * @param initremote - if set to true, a DO is sent upon connection.
	 * @param acceptlocal - if set to true, any DO request is accepted.
	 * @param acceptremote - if set to true, any WILL request is accepted.
	 ***/
	public WindowSizeOptionHandler(int nWidth, int nHeight, boolean initlocal, boolean initremote, boolean acceptlocal,
			boolean acceptremote) {
		super(TelnetOption.WINDOW_SIZE, initlocal, initremote, acceptlocal, acceptremote);

		m_nWidth = nWidth;
		m_nHeight = nHeight;
	}

	/***
	 * Constructor for the WindowSizeOptionHandler. Initial and accept behaviour flags are set to
	 * false
	 * 

	 * 
	 * @param nWidth - Window width.
	 * @param nHeight - Window Height
	 ***/
	public WindowSizeOptionHandler(int nWidth, int nHeight) {
		super(TelnetOption.WINDOW_SIZE, false, false, false, false);

		m_nWidth = nWidth;
		m_nHeight = nHeight;
	}

	/***
	 * Implements the abstract method of TelnetOptionHandler. This will send the client Height and
	 * Width to the server.
	 * 
	 * 
	 * @return array to send to remote system
	 ***/
	@Override
	public int[] startSubnegotiationLocal() {
		int nCompoundWindowSize = m_nWidth * 0x10000 + m_nHeight;
		int nResponseSize = 5;
		int nIndex;
		int nShift;
		int nTurnedOnBits;

		if ((m_nWidth % 0x100) == 0xFF) {
			nResponseSize += 1;
		}

		if ((m_nWidth / 0x100) == 0xFF) {
			nResponseSize += 1;
		}

		if ((m_nHeight % 0x100) == 0xFF) {
			nResponseSize += 1;
		}

		if ((m_nHeight / 0x100) == 0xFF) {
			nResponseSize += 1;
		}

		//
		// allocate response array
		//
		int response[] = new int[nResponseSize];

		//
		// Build response array.
		// ---------------------
		// 1. put option name.
		// 2. loop through Window size and fill the values,
		// 3. duplicate 'ff' if needed.
		//

		response[0] = WINDOW_SIZE; // 1 //

		for ( // 2 //
		nIndex = 1, nShift = 24; nIndex < nResponseSize; nIndex++, nShift -= 8) {
			nTurnedOnBits = 0xFF;
			nTurnedOnBits <<= nShift;
			response[nIndex] = (nCompoundWindowSize & nTurnedOnBits) >>> nShift;

			if (response[nIndex] == 0xff) { // 3 //
				nIndex++;
				response[nIndex] = 0xff;
			}
		}

		return response;
	}

}