asnsequence.java

snmp zip 包开发snmp协议

// NAME
//      $RCSfile: AsnSequence.java,v $
// DESCRIPTION
//      [given below in javadoc format]
// DELTA
//      $Revision: 3.14 $
// CREATED
//      $Date: 2006/01/17 17:43:54 $
// COPYRIGHT
//      Westhawk Ltd
// TO DO
//

/*
 * Copyright (C) 1995, 1996 by West Consulting BV
 *
 * Permission to use, copy, modify, and distribute this software
 * for any purpose and without fee is hereby granted, provided
 * that the above copyright notices appear in all copies and that
 * both the copyright notice and this permission notice appear in
 * supporting documentation.
 * This software is provided "as is" without express or implied
 * warranty.
 * author <a href="mailto:[e-mail]">Tim Panton</a>
 * original version by [e-mail] (Jordan Hargrave)
 */

/*
 * Copyright (C) 1996 - 2006 by Westhawk Ltd
 * <a href="www.westhawk.co.uk">www.westhawk.co.uk</a>
 *
 * Permission to use, copy, modify, and distribute this software
 * for any purpose and without fee is hereby granted, provided
 * that the above copyright notices appear in all copies and that
 * both the copyright notice and this permission notice appear in
 * supporting documentation.
 * This software is provided "as is" without express or implied
 * warranty.
 * author <a href="mailto:[e-mail]">Tim Panton</a>
 */

package uk.co.westhawk.snmp.stack;

import java.io.*;
import java.util.*;


/**
 * This class represents the ASN.1 sequence class.
 * This class contains a Sequence of AsnObjects.
 *
 * @author <a href="mailto:[e-mail]">Tim Panton</a>
 * @version $Revision: 3.14 $ $Date: 2006/01/17 17:43:54 $
 */
class AsnSequence extends AsnObject
{
    private static final String     version_id =
        "@(#)$Id: AsnSequence.java,v 3.14 2006/01/17 17:43:54 birgit Exp $ Copyright Westhawk Ltd";

    private Vector children;

    /** 
     * Constructors.
     */
    AsnSequence() 
    {
        this(CONS_SEQ);
    }

    /** 
     * Constructors.
     */
    AsnSequence(byte oddtype) 
    {
        type     = oddtype;
        children = new Vector(1, 1);
    }
    

    /** 
     * Constructors.
     * @param pos The position of the first child
     */
    AsnSequence(InputStream in, int len, int pos) throws IOException 
    {
        this();
        if (debug > 10)
        {
            System.out.println("AsnSequence(): Length = " + len
                + ", Pos = " + pos);
        }
        AsnObject a = null;
        while (true)
        {
            a = AsnReadHeader(in, pos);
            if (a != null)
            {
                pos += (a.headerLength + a.contentsLength);
                add(a);
            } 
            else 
            {
                break; // all done
            }
        }
    }

    /** 
     * Returns the string representation of the AsnSequence.
     *
     * @return The string of the AsnSequence
     */
    public String toString()
    {
        return "";
    }

    /** 
     * Adds a child to the sequence.
     */
    AsnObject add(AsnObject child) 
    {
        if (child.isCorrect == true)
        {
            children.addElement(child);
        }
        return child;
    }

    /**
     * Replaces one child by the other.
     * This is used by v3 to insert the security / auth fingerprint.
     */
    AsnObject replaceChild(AsnObject oldChild, AsnObject newChild) 
    {
        AsnObject ret = oldChild;
        int at = children.indexOf(oldChild);
        if (at > 0) 
        {
            children.setElementAt(newChild, at);
            ret = newChild;
        }
        return ret;
    }

    /** 
     * Returns the total size of the children.
     */
    int size() throws EncodingException
    {
        Enumeration childList = children.elements();
        int         cnt, sz = 0;
        
        while(childList.hasMoreElements()) 
        {
          // Get size of child
          cnt = ((AsnObject)childList.nextElement()).size();
          
          // Add space for type byte & length encoding
          cnt += (1+getLengthBytes(cnt));
          sz += cnt;
        }
        return sz;
    }

    void write(OutputStream out)
    throws IOException, EncodingException
    {
        write(out, 0);
    }
    void write(OutputStream out, int pos)
    throws IOException, EncodingException
    {
        // Output header
        int length = size();
        startPos = pos;
        AsnBuildHeader(out, type, length);
        if (debug > 10)
        {
            System.out.println("\tAsnSequence.write(): begin, startPos = "
                + startPos);
        }
        
        // Output children
        pos += headerLength;
        Enumeration childList = children.elements();
        while(childList.hasMoreElements()) 
        {
            AsnObject child = ((AsnObject)childList.nextElement());
            child.write(out, pos);
            child.startPos = pos;
            pos += child.headerLength + child.contentsLength;
        }

        if (debug > 10)
        {
            System.out.println("\tAsnSequence.write(): end");
        }
    }
    

    /** 
     * recursively look for a pduSequence object.
     */
    AsnObject findPdu() 
    {
        AsnObject res = null;

        Enumeration childList = children.elements();
        while(childList.hasMoreElements()) 
        {
            AsnObject child = ((AsnObject)childList.nextElement());
            res = child.findPdu();
            if (res != null) 
            {
                break;
            }
        } 

        if (this.isCorrect == false && res != null)
        {
            res.isCorrect = false;
        }
        return res;  
    }

    /** 
     * recursively look for a trapPduv1Sequence object.
     */
    AsnObject findTrapPduv1()
    {
        AsnObject res = null;

        Enumeration childList = children.elements();
        while(childList.hasMoreElements()) 
        {
            AsnObject child = ((AsnObject)childList.nextElement());
            res = child.findTrapPduv1();
            if (res != null) 
            {
                break;
            }
        } 
        if (this.isCorrect == false && res != null)
        {
            res.isCorrect = false;
        }
        return res;  
    }

    AsnObject getObj(int offset) 
    {
        AsnObject res = new AsnNull();
        try
        {
            res = (AsnObject) children.elementAt(offset);
        }
        catch (ArrayIndexOutOfBoundsException exc)
        {
        }
        return res;
    }

    int getObjCount()
    {
        return children.size();
    }

}