/*

 * Copyright 2000-2006 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 org.ietf.jgss;

import java.io.InputStream;

import java.io.IOException;

import sun.security.util.DerValue;

import sun.security.util.DerOutputStream;

import sun.security.util.ObjectIdentifier;

/**

 * This class represents Universal Object Identifiers (Oids) and their

 * associated operations.<p>

 *

 * Oids are hierarchically globally-interpretable identifiers used

 * within the GSS-API framework to identify mechanisms and name formats.<p>

 *

 * The structure and encoding of Oids is defined in ISOIEC-8824 and

 * ISOIEC-8825.  For example the Oid representation of Kerberos V5

 * mechanism is "1.2.840.113554.1.2.2"<p>

 *

 * The GSSName name class contains public static Oid objects

 * representing the standard name types defined in GSS-API.

 *

 * @author Mayank Upadhyay

 * @since 1.4

 */

public class Oid {

    private ObjectIdentifier oid;

    private byte[] derEncoding;

    /**

     * Constructs an Oid object from a string representation of its

     * integer components.

     *

     * @param strOid the dot separated string representation of the oid.

     * For instance, "1.2.840.113554.1.2.2".

     * @exception GSSException may be thrown when the string is incorrectly

     *     formatted

     */

    public Oid(String strOid) throws GSSException {

        try {

            oid = new ObjectIdentifier(strOid);

            derEncoding = null;

        } catch (Exception e) {

            throw new GSSException(GSSException.FAILURE,

                          "Improperly formatted Object Identifier String - "

                          + strOid);

        }

    }

    /**

     * Creates an Oid object from its ASN.1 DER encoding.  This refers to

     * the full encoding including tag and length.  The structure and

     * encoding of Oids is defined in ISOIEC-8824 and ISOIEC-8825.  This

     * method is identical in functionality to its byte array counterpart.

     *

     * @param derOid stream containing the DER encoded oid

     * @exception GSSException may be thrown when the DER encoding does not

     *  follow the prescribed format.

     */

    public Oid(InputStream derOid) throws GSSException {

        try {

            DerValue derVal = new DerValue(derOid);

            derEncoding = derVal.toByteArray();

            oid = derVal.getOID();

        } catch (IOException e) {

            throw new GSSException(GSSException.FAILURE,

                          "Improperly formatted ASN.1 DER encoding for Oid");

        }

    }

    /**

     * Creates an Oid object from its ASN.1 DER encoding.  This refers to

     * the full encoding including tag and length.  The structure and

     * encoding of Oids is defined in ISOIEC-8824 and ISOIEC-8825.  This

     * method is identical in functionality to its InputStream conterpart.

     *

     * @param data byte array containing the DER encoded oid

     * @exception GSSException may be thrown when the DER encoding does not

     *     follow the prescribed format.

     */

    public Oid(byte [] data) throws GSSException {

        try {

            DerValue derVal = new DerValue(data);

            derEncoding = derVal.toByteArray();

            oid = derVal.getOID();

        } catch (IOException e) {

            throw new GSSException(GSSException.FAILURE,

                          "Improperly formatted ASN.1 DER encoding for Oid");

        }

    }

    /**

     * Only for calling by initializators used with declarations.

     *

     * @param strOid

     */

    static Oid getInstance(String strOid) {

        Oid retVal = null;

        try {

            retVal =  new Oid(strOid);

        } catch (GSSException e) {

            // squelch it!

        }

        return retVal;

    }

    /**

     * Returns a string representation of the oid's integer components

     * in dot separated notation.

     *

     * @return string representation in the following format: "1.2.3.4.5"

     */

    public String toString() {

        return oid.toString();

    }

    /**

     * Tests if two Oid objects represent the same Object identifier

     * value.

     *

     * @return <code>true</code> if the two Oid objects represent the same

     * value, <code>false</code> otherwise.

     * @param other the Oid object that has to be compared to this one

     */

    public boolean equals(Object other) {

        //check if both reference the same object

        if (this == other)

            return (true);

        if (other instanceof Oid)

            return this.oid.equals(((Oid) other).oid);

        else if (other instanceof ObjectIdentifier)

            return this.oid.equals(other);

        else

            return false;

    }

    /**

     * Returns the full ASN.1 DER encoding for this oid object, which

     * includes the tag and length.

     *

     * @return byte array containing the DER encoding of this oid object.

     * @exception GSSException may be thrown when the oid can't be encoded

     */

    public byte[] getDER() throws GSSException {

        if (derEncoding == null) {

            DerOutputStream dout = new DerOutputStream();

            try {

                dout.putOID(oid);

            } catch (IOException e) {

                throw new GSSException(GSSException.FAILURE, e.getMessage());

            }

            derEncoding = dout.toByteArray();

        }

        return derEncoding.clone();

    }

    /**

     * A utility method to test if this Oid value is contained within the

     * supplied Oid array.

     *

     * @param oids the array of Oid's to search

     * @return true if the array contains this Oid value, false otherwise

     */

    public boolean containedIn(Oid[] oids) {

        for (int i = 0; i < oids.length; i++) {

            if (oids[i].equals(this))

                return (true);

        }

        return (false);

    }

    /**

     * Returns a hashcode value for this Oid.

     *

     * @return a hashCode value

     */

    public int hashCode() {

        return oid.hashCode();

    }

}