/* Copyright (c) 2000 The Legion Of The Bouncy Castle
 * (http://www.bouncycastle.org)
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package jcifs.spnego.asn1;

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

public class DEROutputStream
    extends FilterOutputStream implements DERTags
{
    public DEROutputStream(
        OutputStream    os)
    {
        super(os);
    }

    private void writeLength(
        int length)
        throws IOException
    {
        if (length > 127)
        {
            int size = 1;
            int val = length;

            while ((val >>>= 8) != 0)
            {
                size++;
            }

            write((byte)(size | 0x80));

            for (int i = (size - 1) * 8; i >= 0; i -= 8)
            {
                write((byte)(length >> i));
            }
        }
        else
        {
            write((byte)length);
        }
    }

    void writeEncoded(
        int     tag,
        byte[]  bytes)
        throws IOException
    {
        write(tag);
        writeLength(bytes.length);
        write(bytes);
    }

    protected void writeNull()
        throws IOException
    {
        write(NULL);
        write(0x00);
    }

    public void writeObject(
        Object    obj)
        throws IOException
    {
        if (obj == null)
        {
            writeNull();
        }
        else if (obj instanceof DERObject)
        {
            ((DERObject)obj).encode(this);
        }
        else if (obj instanceof DEREncodable)
        {
            ((DEREncodable)obj).getDERObject().encode(this);
        }
        else 
        {
            throw new IOException("object not DEREncodable");
        }
    }
}