berconstructedoctetstring.java

来自「《移动Agent技术》一书的所有章节源代码。」· Java 代码 · 共 146 行

package org.bouncycastle.asn1;

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

public class BERConstructedOctetString
    extends DEROctetString
{
    /**
     * convert a vector of octet strings into a single byte string
     */
    static private byte[] toBytes(
        Vector  octs)
    {
        ByteArrayOutputStream   bOut = new ByteArrayOutputStream();

        for (int i = 0; i != octs.size(); i++)
        {
            DEROctetString  o = (DEROctetString)octs.elementAt(i);

            try
            {
                bOut.write(o.getOctets());
            }
            catch (IOException e)
            {
                throw new RuntimeException("exception converting octets " + e.toString());
            }
        }

        return bOut.toByteArray();
    }

    private Vector  octs;

    /**
     * @param string the octets making up the octet string.
     */
    public BERConstructedOctetString(
        byte[]  string)
    {
		super(string);
    }

    public BERConstructedOctetString(
        Vector  octs)
    {
		super(toBytes(octs));

        this.octs = octs;
    }

    public BERConstructedOctetString(
        DERObject  obj)
    {
		super(obj);
    }

    public BERConstructedOctetString(
        DEREncodable  obj)
    {
        super(obj.getDERObject());
    }

    public byte[] getOctets()
    {
        return string;
    }

    public Vector getDEROctets()
    {
        if (octs == null)
        {
            octs = generateOcts();
        }

        return octs;
    }

    private Vector generateOcts()
    {
        int     start = 0;
        int     end = 0;
        Vector  vec = new Vector();

        while (end < string.length)
        {
            if ((end + 1) < string.length)
            {
                if (string[end] == 0 && string[end + 1] == 0)
                {
                    byte[]  nStr = new byte[end - start + 1];

                    for (int i = 0; i != nStr.length; i++)
                    {
                        nStr[i] = string[start + i];
                    }

                    vec.addElement(new DEROctetString(nStr));
                    start = end + 1;
                }
            }
            end++;
        }

        byte[]  nStr = new byte[end - start];
        for (int i = 0; i != nStr.length; i++)
        {
            nStr[i] = string[start + i];
        }

        vec.addElement(new DEROctetString(nStr));

        return vec;
    }

    public void encode(
        DEROutputStream out)
        throws IOException
    {
		if (out instanceof BEROutputStream)
		{
            out.write(CONSTRUCTED | OCTET_STRING);

            out.write(0x80);

            if (octs == null)
            {
                octs = generateOcts();
            }

            for (int i = 0; i != octs.size(); i++)
            {
                out.writeObject(octs.elementAt(i));
            }

            out.write(0x00);
            out.write(0x00);
		}
		else
		{
			super.encode(out);
		}
    }
}