/*

 * Copyright 1997-2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.security.x509;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.Date;

import java.util.Enumeration;

import sun.security.util.*;

/**

 * This class defines the version of the X509 Certificate.

 *

 * @author Amit Kapoor

 * @author Hemma Prafullchandra

 * @see CertAttrSet

 */

public class CertificateVersion implements CertAttrSet<String> {

    /**

     * X509Certificate Version 1

     */

    public static final int     V1 = 0;

    /**

     * X509Certificate Version 2

     */

    public static final int     V2 = 1;

    /**

     * X509Certificate Version 3

     */

    public static final int     V3 = 2;

    /**

     * Identifier for this attribute, to be used with the

     * get, set, delete methods of Certificate, x509 type.

     */

    public static final String IDENT = "x509.info.version";

    /**

     * Sub attributes name for this CertAttrSet.

     */

    public static final String NAME = "version";

    public static final String VERSION = "number";

    // Private data members

    int version = V1;

    // Returns the version number.

    private int getVersion() {

        return(version);

    }

    // Construct the class from the passed DerValue

    private void construct(DerValue derVal) throws IOException {

        if (derVal.isConstructed() && derVal.isContextSpecific()) {

            derVal = derVal.data.getDerValue();

            version = derVal.getInteger();

            if (derVal.data.available() != 0) {

                throw new IOException("X.509 version, bad format");

            }

        }

    }

    /**

     * The default constructor for this class,

     *  sets the version to 0 (i.e. X.509 version 1).

     */

    public CertificateVersion() {

        version = V1;

    }

    /**

     * The constructor for this class for the required version.

     *

     * @param version the version for the certificate.

     * @exception IOException if the version is not valid.

     */

    public CertificateVersion(int version) throws IOException {

        // check that it is a valid version

        if (version == V1 || version == V2 || version == V3)

            this.version = version;

        else {

            throw new IOException("X.509 Certificate version " +

                                   version + " not supported.\n");

        }

    }

    /**

     * Create the object, decoding the values from the passed DER stream.

     *

     * @param in the DerInputStream to read the CertificateVersion from.

     * @exception IOException on decoding errors.

     */

    public CertificateVersion(DerInputStream in) throws IOException {

        version = V1;

        DerValue derVal = in.getDerValue();

        construct(derVal);

    }

    /**

     * Create the object, decoding the values from the passed stream.

     *

     * @param in the InputStream to read the CertificateVersion from.

     * @exception IOException on decoding errors.

     */

    public CertificateVersion(InputStream in) throws IOException {

        version = V1;

        DerValue derVal = new DerValue(in);

        construct(derVal);

    }

    /**

     * Create the object, decoding the values from the passed DerValue.

     *

     * @param val the Der encoded value.

     * @exception IOException on decoding errors.

     */

    public CertificateVersion(DerValue val) throws IOException {

        version = V1;

        construct(val);

    }

    /**

     * Return the version number of the certificate.

     */

    public String toString() {

        return("Version: V" + (version+1));

    }

    /**

     * Encode the CertificateVersion period in DER form to the stream.

     *

     * @param out the OutputStream to marshal the contents to.

     * @exception IOException on errors.

     */

    public void encode(OutputStream out) throws IOException {

        // Nothing for default

        if (version == V1) {

            return;

        }

        DerOutputStream tmp = new DerOutputStream();

        tmp.putInteger(version);

        DerOutputStream seq = new DerOutputStream();

        seq.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)0),

                  tmp);

        out.write(seq.toByteArray());

    }

    /**

     * Set the attribute value.

     */

    public void set(String name, Object obj) throws IOException {

        if (!(obj instanceof Integer)) {

            throw new IOException("Attribute must be of type Integer.");

        }

        if (name.equalsIgnoreCase(VERSION)) {

            version = ((Integer)obj).intValue();

        } else {

            throw new IOException("Attribute name not recognized by " +

                                  "CertAttrSet: CertificateVersion.");

        }

    }

    /**

     * Get the attribute value.

     */

    public Object get(String name) throws IOException {

        if (name.equalsIgnoreCase(VERSION)) {

            return(new Integer(getVersion()));

        } else {

            throw new IOException("Attribute name not recognized by " +

                                  "CertAttrSet: CertificateVersion.");

        }

    }

    /**

     * Delete the attribute value.

     */

    public void delete(String name) throws IOException {

        if (name.equalsIgnoreCase(VERSION)) {

            version = V1;

        } else {

            throw new IOException("Attribute name not recognized by " +

                                  "CertAttrSet: CertificateVersion.");

        }

    }

    /**

     * Return an enumeration of names of attributes existing within this

     * attribute.

     */

    public Enumeration<String> getElements() {

        AttributeNameEnumeration elements = new AttributeNameEnumeration();

        elements.addElement(VERSION);

        return (elements.elements());

    }

    /**

     * Return the name of this attribute.

     */

    public String getName() {

        return(NAME);

    }

    /**

     * Compare versions.

     */

    public int compare(int vers) {

        return(version - vers);

    }

}