/*
 * Copyright (C) 2005-2006 Alfresco, Inc.
 *
 * Licensed under the Mozilla Public License version 1.1 
 * with a permitted attribution clause. You may obtain a
 * copy of the License at
 *
 *   http://www.alfresco.org/legal/license.txt
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the
 * License.
 */
package org.alfresco.filesys.server.auth.passthru;

import java.io.IOException;

import org.alfresco.filesys.netbios.NetBIOSSession;
import org.alfresco.filesys.netbios.RFCNetBIOSProtocol;
import org.alfresco.filesys.smb.NetworkSession;
import org.alfresco.filesys.smb.PacketType;
import org.alfresco.filesys.smb.SMBException;
import org.alfresco.filesys.smb.SMBStatus;
import org.alfresco.filesys.util.DataPacker;

/**
 * SMB packet type class
 * 
 * @author GKSpencer
 */
public class SMBPacket
{

    // SMB packet offsets, assuming an RFC NetBIOS transport

    public static final int SIGNATURE   = RFCNetBIOSProtocol.HEADER_LEN;
    public static final int COMMAND     = 4 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int ERRORCODE   = 5 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int ERRORCLASS  = 5 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int ERROR       = 7 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int FLAGS       = 9 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int FLAGS2      = 10 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int PIDHIGH     = 12 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int SID         = 18 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int SEQNO       = 20 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int TID         = 24 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int PID         = 26 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int UID         = 28 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int MID         = 30 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int WORDCNT     = 32 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int ANDXCOMMAND = 33 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int ANDXRESERVED = 34 + RFCNetBIOSProtocol.HEADER_LEN;
    public static final int PARAMWORDS  = 33 + RFCNetBIOSProtocol.HEADER_LEN;

    // SMB packet header length for a transaction type request

    public static final int TRANS_HEADERLEN = 66 + RFCNetBIOSProtocol.HEADER_LEN;

    // Minimum receive length for a valid SMB packet

    public static final int MIN_RXLEN = 32;

    // Default buffer size to allocate for SMB packets

    public static final int DEFAULT_BUFSIZE = 4096;

    // Flag bits

    public static final int FLG_SUBDIALECT  = 0x01;
    public static final int FLG_CASELESS    = 0x08;
    public static final int FLG_CANONICAL   = 0x10;
    public static final int FLG_OPLOCK      = 0x20;
    public static final int FLG_NOTIFY      = 0x40;
    public static final int FLG_RESPONSE    = 0x80;

    // Flag2 bits

    public static final int FLG2_LONGFILENAMES      = 0x0001;
    public static final int FLG2_EXTENDEDATTRIB     = 0x0002;
    public static final int FLG2_EXTENDEDSECURITY   = 0x0800;
    public static final int FLG2_READIFEXE          = 0x2000;
    public static final int FLG2_LONGERRORCODE      = 0x4000;
    public static final int FLG2_UNICODE            = 0x8000;

    // Security mode bits

    public static final int SEC_USER = 0x0001;
    public static final int SEC_ENCRYPT = 0x0002;

    // Raw mode bits

    public static final int RAW_READ = 0x0001;
    public static final int RAW_WRITE = 0x0002;

    // SMB packet buffer

    private byte[] m_smbbuf;

    // Packet type

    private int m_pkttype;

    // Current byte area pack/unpack position

    protected int m_pos;
    protected int m_endpos;

    // Time of last packet send

    protected long m_lastTxTime;

    /**
     * Default constructor
     */
    public SMBPacket()
    {
        m_smbbuf = new byte[DEFAULT_BUFSIZE];
        InitializeBuffer();
    }

    /**
     * Construct an SMB packet using the specified packet buffer.
     * 
     * @param buf SMB packet buffer.
     */
    public SMBPacket(byte[] buf)
    {
        m_smbbuf = buf;
    }

    /**
     * Construct an SMB packet of the specified size.
     * 
     * @param siz Size of SMB packet buffer to allocate.
     */
    public SMBPacket(int siz)
    {
        m_smbbuf = new byte[siz];
        InitializeBuffer();
    }

    /**
     * Check if a received SMB is valid, if not then throw an exception
     * 
     * @exception SMBException
     */
    public final void checkForError() throws SMBException
    {

        // Check if a valid SMB response has been received

        if (isValidResponse() == false)
        {

            // Check for NT error codes

            if (isLongErrorCode())
                throw new SMBException(SMBStatus.NTErr, getLongErrorCode());
            else
                throw new SMBException(getErrorClass(), getErrorCode());
        }
    }

    /**
     * Clear the data byte count
     */
    public final void clearBytes()
    {
        int offset = getByteOffset() - 2;
        DataPacker.putIntelShort(0, m_smbbuf, offset);
    }

    /**
     * Check if the error class/code match the specified error/class
     * 
     * @param errClass int
     * @param errCode int
     * @return boolean
     */
    public final boolean equalsError(int errClass, int errCode)
    {
        if (getErrorClass() == errClass && getErrorCode() == errCode)
            return true;
        return false;
    }

    /**
     * Send the SMB packet and receive the response packet
     * 
     * @param sess Network session to send/receive the packet over.
     * @param rxPkt SMB packet to receive the response into.
     * @param throwerr If true then throw an I/O error if an invalid response is received.
     * @exception java.io.IOException If a network error occurs.
     * @exception SMBException If an SMB level error occurs
     */
    protected final synchronized void ExchangeLowLevelSMB(NetworkSession sess, SMBPacket rxPkt, boolean throwerr)
            throws java.io.IOException, SMBException
    {

        // Set multiplex id

        if (getMultiplexId() == 0)
            setMultiplexId(1);

        // Send the SMB request

        sess.Send(m_smbbuf, getLength());

        // Receive a response

        if (sess.Receive(rxPkt.getBuffer(), 0) >= MIN_RXLEN)
        {

            // Check if the response is for the current request

            if (rxPkt.getCommand() == m_pkttype)
            {

                // Check if a valid SMB response has been received

                if (throwerr == true)
                    checkForError();

                // Valid packet received, return to caller

                return;
            }
        }

        // Invalid receive packet

        throw new java.io.IOException("Invalid SMB Receive Packet");
    }

    /**
     * Send/receive an SMB protocol packet to the remote server.
     * 
     * @param sess SMB session to send/receive data on.
     * @param rxPkt SMB packet to receive the response into.
     * @exception java.io.IOException If an I/O error occurs.
     * @exception SMBException If an SMB level error occurs.
     */
    public synchronized final void ExchangeSMB(AuthenticateSession sess, SMBPacket rxPkt) throws SMBException,
            IOException
    {

        // Call the main SMB exhchange method

        ExchangeSMB(sess, rxPkt, false);
    }

    /**
     * Send the SMB packet and receive the response packet
     * 
     * @param sess SMB session to send/receive the packet over.
     * @param rxPkt SMB packet to receive the response into.
     * @param throwerr If true then throw an I/O error if an invalid response is received.
     * @exception java.io.IOException If an I/O error occurs.
     * @exception SMBException If an SMB level error occurs.
     */
    public synchronized final void ExchangeSMB(AuthenticateSession sess, SMBPacket rxPkt, boolean throwerr)
            throws SMBException, IOException
    {

        // Set the process id, user id and multiplex id

        setProcessId(sess.getProcessId());
        setUserId(sess.getUserId());

        if (getMultiplexId() == 0)
            setMultiplexId(1);

        // Get the network session

        NetworkSession netSess = sess.getSession();

        // Send the SMB request

        netSess.Send(m_smbbuf, getLength());

        // Receive the response, other asynchronous responses may be received before the response
        // for this request

        boolean rxValid = false;

        while (rxValid == false)
        {

            // Receive a response

            if (netSess.Receive(rxPkt.getBuffer(), RFCNetBIOSProtocol.TMO) >= MIN_RXLEN)
            {

                // Check if the response is for the current request

                if (rxPkt.getCommand() == m_pkttype)
                {

                    // Check if a valid SMB response has been received

                    if (throwerr == true)
                        checkForError();

                    // Valid packet received, return to caller

                    return;
                }
            }
        }

        // Invalid receive packet

        throw new java.io.IOException("Invalid SMB Receive Packet");
    }

    /**
     * Get the secondary command code
     * 
     * @return Secondary command code
     */
    public final int getAndXCommand()
    {
        return (int) (m_smbbuf[ANDXCOMMAND] & 0xFF);
    }

    /**
     * Return the byte array used for the SMB packet
     * 
     * @return Byte array used for the SMB packet.
     */
    public final byte[] getBuffer()
    {
        return m_smbbuf;
    }

    /**
     * Return the total buffer size available to the SMB request
     * 
     * @return Total SMB buffer length available.
     */
    public final int getBufferLength()
    {
        return m_smbbuf.length - RFCNetBIOSProtocol.HEADER_LEN;
    }

    /**
     * Return the available buffer space for data bytes
     * 
     * @return int
     */
    public final int getAvailableLength()
    {
        return m_smbbuf.length - DataPacker.longwordAlign(getByteOffset());
    }

    /**
     * Get the data byte count for the SMB packet
     * 
     * @return Data byte count
     */
    public final int getByteCount()
    {

        // Calculate the offset of the byte count

        int pos = PARAMWORDS + (2 * getParameterCount());
        return (int) DataPacker.getIntelShort(m_smbbuf, pos);
    }

    /**
     * Get the data byte area offset within the SMB packet
     * 
     * @return Data byte offset within the SMB packet.
     */
    public final int getByteOffset()
    {

        // Calculate the offset of the byte buffer

        int pCnt = getParameterCount();
        int pos = WORDCNT + (2 * pCnt) + 3;
        return pos;
    }

    /**
     * Get the SMB command
     * 
     * @return SMB command code.
     */
    public final int getCommand()
    {
        return (int) (m_smbbuf[COMMAND] & 0xFF);
    }

    /**
     * Determine if normal or long error codes have been returned
     * 
     * @return boolean
     */
    public final boolean hasLongErrorCode()
    {
        if ((getFlags2() & FLG2_LONGERRORCODE) == 0)
            return false;
        return true;
    }

    /**
     * Return the saved packet type
     * 
     * @return int
     */
    public final int isType()
    {
        return m_pkttype;
    }

    /**
     * Check if the packet contains ASCII or Unicode strings
     * 
     * @return boolean
     */
    public final boolean isUnicode()
    {
        return (getFlags2() & FLG2_UNICODE) != 0 ? true : false;
    }

    /**
     * Check if the packet is using caseless filenames
     * 
     * @return boolean
     */
    public final boolean isCaseless()
    {
        return (getFlags() & FLG_CASELESS) != 0 ? true : false;
    }

    /**
     * Check if long file names are being used
     * 
     * @return boolean
     */
    public final boolean isLongFileNames()
    {
        return (getFlags2() & FLG2_LONGFILENAMES) != 0 ? true : false;
    }

    /**
     * Check if long error codes are being used
     * 
     * @return boolean
     */
    public final boolean isLongErrorCode()
    {
        return (getFlags2() & FLG2_LONGERRORCODE) != 0 ? true : false;
    }

    /**
     * Get the SMB error class
     * 
     * @return SMB error class.
     */
    public final int getErrorClass()
    {
        return (int) m_smbbuf[ERRORCLASS] & 0xFF;
    }

    /**
     * Get the SMB error code
     * 
     * @return SMB error code.
     */
    public final int getErrorCode()
    {
        return (int) m_smbbuf[ERROR] & 0xFF;
    }

    /**
     * Get the SMB flags value.
     * 
     * @return SMB flags value.
     */
    public final int getFlags()
    {
        return (int) m_smbbuf[FLAGS] & 0xFF;
    }

    /**
     * Get the SMB flags2 value.
     * 
     * @return SMB flags2 value.
     */
    public final int getFlags2()
    {
        return (int) DataPacker.getIntelShort(m_smbbuf, FLAGS2);
    }

    /**
     * Calculate the total used packet length.
     * 
     * @return Total used packet length.
     */
    public final int getLength()
    {
        return (getByteOffset() + getByteCount()) - SIGNATURE;
    }

    /**
     * Get the long SMB error code
     * 
     * @return Long SMB error code.
     */
    public final int getLongErrorCode()
    {
        return DataPacker.getIntelInt(m_smbbuf, ERRORCODE);
    }

    /**
     * Get the multiplex identifier.
     * 
     * @return Multiplex identifier.
     */
    public final int getMultiplexId()
    {
        return DataPacker.getIntelShort(m_smbbuf, MID);
    }

    /**
     * Get a parameter word from the SMB packet.
     * 
     * @param idx Parameter index (zero based).
     * @return Parameter word value.
     * @exception java.lang.IndexOutOfBoundsException If the parameter index is out of range.
     */
    public final int getParameter(int idx) throws java.lang.IndexOutOfBoundsException
    {

        // Range check the parameter index

        if (idx > getParameterCount())
            throw new java.lang.IndexOutOfBoundsException();

        // Calculate the parameter word offset

        int pos = WORDCNT + (2 * idx) + 1;
        return (int) (DataPacker.getIntelShort(m_smbbuf, pos) & 0xFFFF);
    }

    /**
     * Get the specified parameter words, as an int value.
     * 
     * @param idx Parameter index (zero based).
     * @param val Parameter value.
     */
    public final int getParameterLong(int idx)
    {
        int pos = WORDCNT + (2 * idx) + 1;
        return DataPacker.getIntelInt(m_smbbuf, pos);
    }

    /**
     * Get the parameter count
     * 
     * @return Parameter word count.
     */
    public final int getParameterCount()
    {
        return (int) m_smbbuf[WORDCNT];
    }

    /**
     * Get the process indentifier (PID)
     * 
     * @return Process identifier value.
     */
    public final int getProcessId()
    {
        return DataPacker.getIntelShort(m_smbbuf, PID);
    }

    /**
     * Get the tree identifier (TID)
     * 
     * @return Tree identifier (TID)
     */
    public final int getTreeId()
    {
        return DataPacker.getIntelShort(m_smbbuf, TID);
    }

    /**
     * Get the user identifier (UID)
     * 
     * @return User identifier (UID)
     */
    public final int getUserId()
    {
        return DataPacker.getIntelShort(m_smbbuf, UID);
    }

    /**
     * Return the last sent packet time
     * 
     * @return long
     */
    public final long getLastPacketSendTime()
    {
        return m_lastTxTime;
    }

    /**
     * Initialize the SMB packet buffer.
     */
    private final void InitializeBuffer()
    {

        // Set the packet signature

        m_smbbuf[SIGNATURE] = (byte) 0xFF;
        m_smbbuf[SIGNATURE + 1] = (byte) 'S';
        m_smbbuf[SIGNATURE + 2] = (byte) 'M';
        m_smbbuf[SIGNATURE + 3] = (byte) 'B';
    }

    /**
     * Determine if this packet is an SMB response, or command packet
     * 
     * @return true if this SMB packet is a response, else false
     */
    public final boolean isResponse()
    {
        int resp = getFlags();
        if ((resp & FLG_RESPONSE) != 0)
            return true;
        return false;
    }

    /**
     * Check if the response packet is valid, ie. type and flags
     * 
     * @return true if the SMB packet is a response packet and the response is valid, else false.
     */
    public final boolean isValidResponse()
    {

        // Check if this is a response packet, and the correct type of packet

        if (isResponse() && getCommand() == m_pkttype)
        {

            // Check if standard error codes or NT 32-bit error codes are being used

            if ((getFlags2() & FLG2_LONGERRORCODE) == 0)
            {
                if (getErrorCode() == SMBStatus.Success)
                    return true;
            }
            else if (getLongErrorCode() == SMBStatus.NTSuccess)
                return true;
        }
        return false;
    }

    /**
     * Pack a byte (8 bit) value into the byte area
     * 
     * @param val byte
     */
    public final void packByte(byte val)
    {
        m_smbbuf[m_pos++] = val;
    }

    /**
     * Pack a byte (8 bit) value into the byte area
     * 
     * @param val int
     */
    public final void packByte(int val)
    {
        m_smbbuf[m_pos++] = (byte) val;
    }

    /**
     * Pack the specified bytes into the byte area
     * 
     * @param byts byte[]
     * @param len int
     */
    public final void packBytes(byte[] byts, int len)
    {
        System.arraycopy(byts, 0, m_smbbuf, m_pos, len);
        m_pos += len;
    }

    /**
     * Pack a string using either ASCII or Unicode into the byte area
     * 
     * @param str String
     * @param uni boolean
     */
    public final void packString(String str, boolean uni)
    {

        // Check for Unicode or ASCII

        if (uni)
        {

            // Word align the buffer position, pack the Unicode string

            m_pos = DataPacker.wordAlign(m_pos);
            DataPacker.putUnicodeString(str, m_smbbuf, m_pos, true);
            m_pos += (str.length() * 2) + 2;
        }
        else
        {

            // Pack the ASCII string

            DataPacker.putString(str, m_smbbuf, m_pos, true);
            m_pos += str.length() + 1;
        }
    }

    /**
     * Pack a word (16 bit) value into the byte area
     * 
     * @param val int
     */
    public final void packWord(int val)
    {
        DataPacker.putIntelShort(val, m_smbbuf, m_pos);
        m_pos += 2;
    }

    /**
     * Pack a 32 bit integer value into the byte area
     * 
     * @param val int
     */
    public final void packInt(int val)
    {
        DataPacker.putIntelInt(val, m_smbbuf, m_pos);
        m_pos += 4;
    }

    /**
     * Pack a long integer (64 bit) value into the byte area
     * 
     * @param val long
     */
    public final void packLong(long val)
    {
        DataPacker.putIntelLong(val, m_smbbuf, m_pos);
        m_pos += 8;
    }

    /**
     * Return the current byte area buffer position
     * 
     * @return int
     */
    public final int getPosition()
    {
        return m_pos;
    }

    /**
     * Set the byte area buffer position
     * 
     * @param pos int
     */
    public final void setPosition(int pos)
    {
        m_pos = pos;
    }

    /**
     * Unpack a byte value from the byte area
     * 
     * @return int
     */
    public final int unpackByte()
    {
        return (int) m_smbbuf[m_pos++];
    }

    /**
     * Unpack a block of bytes from the byte area
     * 
     * @param len int
     * @return byte[]
     */
    public final byte[] unpackBytes(int len)
    {
        if (len <= 0)
            return null;

        byte[] buf = new byte[len];
        System.arraycopy(m_smbbuf, m_pos, buf, 0, len);
        m_pos += len;
        return buf;
    }

    /**
     * Unpack a word (16 bit) value from the byte area
     * 
     * @return int
     */
    public final int unpackWord()
    {
        int val = DataPacker.getIntelShort(m_smbbuf, m_pos);
        m_pos += 2;
        return val;
    }

    /**
     * Unpack an integer (32 bit) value from the byte/parameter area
     * 
     * @return int
     */
    public final int unpackInt()
    {
        int val = DataPacker.getIntelInt(m_smbbuf, m_pos);
        m_pos += 4;
        return val;
    }

    /**
     * Unpack a long integer (64 bit) value from the byte area
     * 
     * @return long
     */
    public final long unpackLong()
    {
        long val = DataPacker.getIntelLong(m_smbbuf, m_pos);
        m_pos += 8;
        return val;
    }

    /**
     * Unpack a string from the byte area
     * 
     * @param uni boolean
     * @return String
     */
    public final String unpackString(boolean uni)
    {

        // Check for Unicode or ASCII

        String ret = null;

        if (uni)
        {

            // Word align the current buffer position

            m_pos = DataPacker.wordAlign(m_pos);
            ret = DataPacker.getUnicodeString(m_smbbuf, m_pos, 255);
            if (ret != null)
                m_pos += (ret.length() * 2) + 2;
        }
        else
        {

            // Unpack the ASCII string

            ret = DataPacker.getString(m_smbbuf, m_pos, 255);
            if (ret != null)
                m_pos += ret.length() + 1;
        }

        // Return the string

        return ret;
    }

    /**
     * Unpack a string from the byte area
     * 
     * @param len int
     * @param uni boolean
     * @return String
     */
    public final String unpackString(int len, boolean uni)
    {

        // Check for Unicode or ASCII

        String ret = null;

        if (uni)
        {

            // Word align the current buffer position

            m_pos = DataPacker.wordAlign(m_pos);
            ret = DataPacker.getUnicodeString(m_smbbuf, m_pos, len);
            if (ret != null)
                m_pos += (ret.length() * 2);
        }
        else
        {

            // Unpack the ASCII string

            ret = DataPacker.getString(m_smbbuf, m_pos, len);
            if (ret != null)
                m_pos += ret.length();
        }

        // Return the string

        return ret;
    }

    /**
     * Check if there is more data in the byte area
     * 
     * @return boolean
     */
    public final boolean hasMoreData()
    {
        if (m_pos < m_endpos)
            return true;
        return false;
    }

    /**
     * Receive an SMB response packet.
     * 
     * @param sess NetBIOS session to receive the SMB packet on.
     * @exception java.io.IOException If an I/O error occurs.
     */
    private final void ReceiveSMB(NetBIOSSession sess) throws java.io.IOException
    {

        if (sess.Receive(m_smbbuf, RFCNetBIOSProtocol.TMO) >= MIN_RXLEN)
            return;

        // Not enough data received for an SMB header

        throw new java.io.IOException("Short NetBIOS receive");
    }

    /**
     * Receive an SMB packet on the spceified SMB session.
     * 
     * @param sess SMB session to receive the packet on.
     * @exception java.io.IOException If a network error occurs
     * @exception SMBException If an SMB level error occurs
     */
    protected final void ReceiveSMB(AuthenticateSession sess) throws java.io.IOException, SMBException
    {

        // Call the main receive method

        ReceiveSMB(sess, true);
    }

    /**
     * Receive an SMB packet on the spceified SMB session.
     * 
     * @param sess SMB session to receive the packet on.
     * @param throwErr Flag to indicate if an error is thrown if an error response is received
     * @exception java.io.IOException If a network error occurs
     * @exception SMBException If an SMB level error occurs
     */
    protected final void ReceiveSMB(AuthenticateSession sess, boolean throwErr) throws java.io.IOException,
            SMBException
    {

        // Get the network session

        NetworkSession netSess = sess.getSession();

        // Receive the response, other asynchronous responses may be received before the response
        // for this request

        boolean rxValid = false;

        while (rxValid == false)
        {

            // Receive a response

            if (netSess.Receive(getBuffer(), RFCNetBIOSProtocol.TMO) >= MIN_RXLEN)
            {

                // Check if the response is for the current request

                if (getCommand() == m_pkttype)
                {

                    // Check if a valid SMB response has been received

                    if (throwErr == true)
                        checkForError();

                    // Valid packet received, return to caller

                    return;
                }
            }
            else
            {

                // Not enough data received for an SMB header

                throw new java.io.IOException("Short NetBIOS receive");
            }
        }
    }

    /**
     * Send the SMB packet on the specified SMB session.
     * 
     * @param sess SMB session to send this packet over.
     * @exception java.io.IOException If an I/O error occurs.
     */
    protected final void SendSMB(AuthenticateSession sess) throws java.io.IOException
    {

        // Update the last send time

        m_lastTxTime = System.currentTimeMillis();

        // Send the SMB request

        sess.getSession().Send(m_smbbuf, getLength());
    }

    /**
     * Set the secondary SMB command
     * 
     * @param cmd Secondary SMB command code.
     */
    public final void setAndXCommand(int cmd)
    {

        // Set the chained command packet type

        m_smbbuf[ANDXCOMMAND] = (byte) cmd;
        m_smbbuf[ANDXRESERVED] = (byte) 0;

        // If the AndX command is disabled clear the offset to the chained packet

        if (cmd == PacketType.NoChainedCommand)
            setParameter(1, 0);
    }

    /**
     * Set the data byte count for this SMB packet
     * 
     * @param cnt Data byte count.
     */
    public final void setByteCount(int cnt)
    {
        int offset = getByteOffset() - 2;
        DataPacker.putIntelShort(cnt, m_smbbuf, offset);
    }

    /**
     * Set the data byte count for this SMB packet
     */

    public final void setByteCount()
    {
        int offset = getByteOffset() - 2;
        int len = m_pos - getByteOffset();
        DataPacker.putIntelShort(len, m_smbbuf, offset);
    }

    /**
     * Set the data byte area in the SMB packet
     * 
     * @param byts Byte array containing the data to be copied to the SMB packet.
     */
    public final void setBytes(byte[] byts)
    {
        int offset = getByteOffset() - 2;
        DataPacker.putIntelShort(byts.length, m_smbbuf, offset);

        offset += 2;

        for (int idx = 0; idx < byts.length; m_smbbuf[offset + idx] = byts[idx++])
            ;
    }

    /**
     * Set the SMB command
     * 
     * @param cmd SMB command code
     */
    public final void setCommand(int cmd)
    {
        m_pkttype = cmd;
        m_smbbuf[COMMAND] = (byte) cmd;
    }

    /**
     * Set the SMB error class.
     * 
     * @param cl SMB error class.
     */
    public final void setErrorClass(int cl)
    {
        m_smbbuf[ERRORCLASS] = (byte) (cl & 0xFF);
    }

    /**
     * Set the SMB error code
     * 
     * @param sts SMB error code.
     */
    public final void setErrorCode(int sts)
    {
        m_smbbuf[ERROR] = (byte) (sts & 0xFF);
    }

    /**
     * Set the SMB flags value.
     * 
     * @param flg SMB flags value.
     */
    public final void setFlags(int flg)
    {
        m_smbbuf[FLAGS] = (byte) flg;
    }

    /**
     * Set the SMB flags2 value.
     * 
     * @param flg SMB flags2 value.
     */
    public final void setFlags2(int flg)
    {
        DataPacker.putIntelShort(flg, m_smbbuf, FLAGS2);
    }

    /**
     * Set the multiplex identifier.
     * 
     * @param mid Multiplex identifier
     */
    public final void setMultiplexId(int mid)
    {
        DataPacker.putIntelShort(mid, m_smbbuf, MID);
    }

    /**
     * Set the specified parameter word.
     * 
     * @param idx Parameter index (zero based).
     * @param val Parameter value.
     */
    public final void setParameter(int idx, int val)
    {
        int pos = WORDCNT + (2 * idx) + 1;
        DataPacker.putIntelShort(val, m_smbbuf, pos);
    }

    /**
     * Set the specified parameter words.
     * 
     * @param idx Parameter index (zero based).
     * @param val Parameter value.
     */

    public final void setParameterLong(int idx, int val)
    {
        int pos = WORDCNT + (2 * idx) + 1;
        DataPacker.putIntelInt(val, m_smbbuf, pos);
    }

    /**
     * Set the parameter count
     * 
     * @param cnt Parameter word count.
     */
    public final void setParameterCount(int cnt)
    {
        m_smbbuf[WORDCNT] = (byte) cnt;
    }

    /**
     * Set the process identifier value (PID).
     * 
     * @param pid Process identifier value.
     */
    public final void setProcessId(int pid)
    {
        DataPacker.putIntelShort(pid, m_smbbuf, PID);
    }

    /**
     * Set the packet sequence number, for connectionless commands.
     * 
     * @param seq Sequence number.
     */
    public final void setSeqNo(int seq)
    {
        DataPacker.putIntelShort(seq, m_smbbuf, SEQNO);
    }

    /**
     * Set the session id.
     * 
     * @param sid Session id.
     */
    public final void setSID(int sid)
    {
        DataPacker.putIntelShort(sid, m_smbbuf, SID);
    }

    /**
     * Set the tree identifier (TID)
     * 
     * @param tid Tree identifier value.
     */
    public final void setTreeId(int tid)
    {
        DataPacker.putIntelShort(tid, m_smbbuf, TID);
    }

    /**
     * Set the user identifier (UID)
     * 
     * @param uid User identifier value.
     */
    public final void setUserId(int uid)
    {
        DataPacker.putIntelShort(uid, m_smbbuf, UID);
    }

    /**
     * Align the byte area pointer on an int (32bit) boundary
     */
    public final void alignBytePointer()
    {
        m_pos = DataPacker.longwordAlign(m_pos);
    }

    /**
     * Reset the byte/parameter pointer area for packing/unpacking data items from the packet
     */
    public final void resetBytePointer()
    {
        m_pos = getByteOffset();
        m_endpos = m_pos + getByteCount();
    }

    /**
     * Reset the byte/parameter pointer area for packing/unpacking data items from the packet, and
     * align the buffer on an int (32bit) boundary
     */
    public final void resetBytePointerAlign()
    {
        m_pos = DataPacker.longwordAlign(getByteOffset());
        m_endpos = m_pos + getByteCount();
    }

    /**
     * Reset the byte/parameter pointer area for packing/unpacking paramaters from the packet
     */
    public final void resetParameterPointer()
    {
        m_pos = PARAMWORDS;
    }

    /**
     * Set the unpack pointer to the specified offset, for AndX processing
     * 
     * @param off int
     * @param len int
     */
    public final void setBytePointer(int off, int len)
    {
        m_pos = off;
        m_endpos = m_pos + len;
    }

    /**
     * Skip a number of bytes in the parameter/byte area
     * 
     * @param cnt int
     */
    public final void skipBytes(int cnt)
    {
        m_pos += cnt;
    }

    /**
     * Return the flags value as a string
     * 
     * @return String
     */
    protected final String getFlagsAsString()
    {

        // Get the flags value

        int flags = getFlags();
        if (flags == 0)
            return "<None>";

        StringBuffer str = new StringBuffer();
        if ((flags & FLG_SUBDIALECT) != 0)
            str.append("SubDialect,");

        if ((flags & FLG_CASELESS) != 0)
            str.append("Caseless,");

        if ((flags & FLG_CANONICAL) != 0)
            str.append("Canonical,");

        if ((flags & FLG_OPLOCK) != 0)
            str.append("Oplock,");

        if ((flags & FLG_NOTIFY) != 0)
            str.append("Notify,");

        if ((flags & FLG_RESPONSE) != 0)
            str.append("Response,");

        str.setLength(str.length() - 1);

        return str.toString();
    }

    /**
     * Return the flags2 value as a string
     * 
     * @return String
     */
    protected final String getFlags2AsString()
    {

        // Get the flags2 value

        int flags2 = getFlags2();

        if (flags2 == 0)
            return "<None>";

        StringBuffer str = new StringBuffer();

        if ((flags2 & FLG2_LONGFILENAMES) != 0)
            str.append("LongFilenames,");

        if ((flags2 & FLG2_EXTENDEDATTRIB) != 0)
            str.append("ExtAttributes,");

        if ((flags2 & FLG2_READIFEXE) != 0)
            str.append("ReadIfEXE,");

        if ((flags2 & FLG2_LONGERRORCODE) != 0)
            str.append("LongErrorCode,");

        if ((flags2 & FLG2_UNICODE) != 0)
            str.append("Unicode,");

        str.setLength(str.length() - 1);

        return str.toString();
    }
}