derbitstring.java

进行与数字证书相关开发必须的java源码

// Decompiled by Jad v1.5.7g. Copyright 2000 Pavel Kouznetsov.
// Jad home page: http://www.geocities.com/SiliconValley/Bridge/8617/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi 
// Source File Name:   DERBitString.java

package jit.asn1;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

// Referenced classes of package jit.asn1:
//            DERObject, ASN1OctetString, ASN1TaggedObject, DEROutputStream, 
//            DEREncodable

public class DERBitString extends DERObject
{

    protected byte data[];
    protected int padBits;

    protected static int getPadBits(int bitString)
    {
        if(bitString == 0)
            return 7;
        int tmp = 0;
        int val;
        if(bitString > 255)
        {
            if(bitString >> 8 > 255)
            {
                if(bitString >> 16 > 255)
                    tmp = 24;
                else
                    tmp = 16;
            } else
            {
                tmp = 8;
            }
            val = bitString >> tmp & 0xff;
        } else
        {
            val = bitString & 0xff;
        }
        int bits;
        for(bits = 1; ((val <<= 1) & 0xff) != 0; bits++);
        return 8 - bits;
    }

    protected static byte[] getBytes(int bitString)
    {
        int bitLen = 0;
        if(bitString >> 24 > 0)
            bitLen = 4;
        else
        if(bitString >> 16 > 0)
            bitLen = 3;
        else
        if(bitString >> 8 > 0)
            bitLen = 2;
        else
            bitLen = 1;
        byte bytes[] = new byte[bitLen];
        for(int i = 0; i < bitLen; i++)
            bytes[i] = (byte)(bitString >> i * 8 & 0xff);

        return bytes;
    }

    public static DERBitString getInstance(Object obj)
    {
        if(obj == null || (obj instanceof DERBitString))
            return (DERBitString)obj;
        if(obj instanceof ASN1OctetString)
        {
            byte bytes[] = ((ASN1OctetString)obj).getOctets();
            int padBits = bytes[0];
            byte data[] = new byte[bytes.length - 1];
            System.arraycopy(bytes, 1, data, 0, bytes.length - 1);
            return new DERBitString(data, padBits);
        }
        if(obj instanceof ASN1TaggedObject)
            return getInstance(((ASN1TaggedObject)obj).getObject());
        else
            throw new IllegalArgumentException("illegal object in getInstance: ".concat(String.valueOf(String.valueOf(obj.getClass().getName()))));
    }

    public static DERBitString getInstance(ASN1TaggedObject obj, boolean explicit)
    {
        return getInstance(obj.getObject());
    }

    protected DERBitString(byte data, int padBits)
    {
        this.data = new byte[4];
        this.data[0] = data;
        this.padBits = padBits;
    }

    public DERBitString(byte data[], int padBits)
    {
        this.data = data;
        this.padBits = padBits;
    }

    public DERBitString(byte data[])
    {
        this(data, 0);
    }

    public DERBitString(DEREncodable obj)
    {
        try
        {
            ByteArrayOutputStream bOut = new ByteArrayOutputStream();
            DEROutputStream dOut = new DEROutputStream(bOut);
            dOut.writeObject(obj);
            dOut.close();
            data = bOut.toByteArray();
            padBits = 0;
        }
        catch(IOException e)
        {
            throw new IllegalArgumentException("Error processing object : ".concat(String.valueOf(String.valueOf(e.toString()))));
        }
    }

    public byte[] getBytes()
    {
        return data;
    }

    public int getPadBits()
    {
        return padBits;
    }

    void encode(DEROutputStream out)
        throws IOException
    {
        byte bytes[] = new byte[getBytes().length + 1];
        bytes[0] = (byte)getPadBits();
        System.arraycopy(getBytes(), 0, bytes, 1, bytes.length - 1);
        out.writeEncoded(3, bytes);
    }

    public boolean equals(Object o)
    {
        if(o == null || !(o instanceof DERBitString))
            return false;
        DERBitString other = (DERBitString)o;
        if(data.length != other.data.length)
            return false;
        for(int i = 0; i != data.length; i++)
            if(data[i] != other.data[i])
                return false;

        return padBits == other.padBits;
    }
}