/*

 * Copyright 2005 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.util.*;

import sun.security.util.BitArray;

import sun.security.util.DerOutputStream;

import sun.security.util.DerValue;

/**

 * Represents the DistributionPointName ASN.1 type.

 *

 * It is used in the CRL Distribution Points Extension (OID = 2.5.29.31)

 * and the Issuing Distribution Point Extension (OID = 2.5.29.28).

 * <p>

 * Its ASN.1 definition is:

 * <pre>

 *

 *     DistributionPointName ::= CHOICE {

 *         fullName                  [0] GeneralNames,

 *         nameRelativeToCRLIssuer   [1] RelativeDistinguishedName }

 *

 *     GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName

 *

 *     GeneralName ::= CHOICE {

 *         otherName                 [0] INSTANCE OF OTHER-NAME,

 *         rfc822Name                [1] IA5String,

 *         dNSName                   [2] IA5String,

 *         x400Address               [3] ORAddress,

 *         directoryName             [4] Name,

 *         ediPartyName              [5] EDIPartyName,

 *         uniformResourceIdentifier [6] IA5String,

 *         iPAddress                 [7] OCTET STRING,

 *         registeredID              [8] OBJECT IDENTIFIER }

 *

 *     RelativeDistinguishedName ::= SET OF AttributeTypeAndValue

 *

 *     AttributeTypeAndValue ::= SEQUENCE {

 *         type    AttributeType,

 *         value   AttributeValue }

 *

 *     AttributeType ::= OBJECT IDENTIFIER

 *

 *     AttributeValue ::= ANY DEFINED BY AttributeType

 *

 * </pre>

 * <p>

 * Instances of this class are designed to be immutable. However, since this

 * is an internal API we do not use defensive cloning for values for

 * performance reasons. It is the responsibility of the consumer to ensure

 * that no mutable elements are modified.

 *

 * @see CRLDistributionPointsExtension

 * @see IssuingDistributionPointExtension

 * @since 1.6

 */

public class DistributionPointName {

    // ASN.1 context specific tag values

    private static final byte TAG_FULL_NAME = 0;

    private static final byte TAG_RELATIVE_NAME = 1;

    // Only one of fullName and relativeName can be set

    private GeneralNames fullName = null;

    private RDN relativeName = null;

    // Cached hashCode value

    private volatile int hashCode;

    /**

     * Creates a distribution point name using a full name.

     *

     * @param fullName the name for the distribution point.

     * @exception IllegalArgumentException if <code>fullName</code> is null.

     */

    public DistributionPointName(GeneralNames fullName) {

        if (fullName == null) {

            throw new IllegalArgumentException("fullName must not be null");

        }

        this.fullName = fullName;

    }

    /**

     * Creates a distribution point name using a relative name.

     *

     * @param relativeName the name of the distribution point relative to

     *        the name of the issuer of the CRL.

     * @exception IllegalArgumentException if <code>relativeName</code> is null.

     */

    public DistributionPointName(RDN relativeName) {

        if (relativeName == null) {

            throw new IllegalArgumentException("relativeName must not be null");

        }

        this.relativeName = relativeName;

    }

    /**

     * Creates a distribution point name from its DER-encoded form.

     *

     * @param encoding the DER-encoded value.

     * @throws IOException on decoding error.

     */

    public DistributionPointName(DerValue encoding) throws IOException {

        if (encoding.isContextSpecific(TAG_FULL_NAME) &&

            encoding.isConstructed()) {

            encoding.resetTag(DerValue.tag_Sequence);

            fullName = new GeneralNames(encoding);

        } else if (encoding.isContextSpecific(TAG_RELATIVE_NAME) &&

            encoding.isConstructed()) {

            encoding.resetTag(DerValue.tag_Set);

            relativeName = new RDN(encoding);

        } else {

            throw new IOException("Invalid encoding for DistributionPointName");

        }

    }

    /**

     * Returns the full name for the distribution point or null if not set.

     */

    public GeneralNames getFullName() {

        return fullName;

    }

    /**

     * Returns the relative name for the distribution point or null if not set.

     */

    public RDN getRelativeName() {

        return relativeName;

    }

    /**

     * Encodes the distribution point name and writes it to the DerOutputStream.

     *

     * @param out the output stream.

     * @exception IOException on encoding error.

     */

    public void encode(DerOutputStream out) throws IOException {

        DerOutputStream theChoice = new DerOutputStream();

        if (fullName != null) {

            fullName.encode(theChoice);

            out.writeImplicit(

                DerValue.createTag(DerValue.TAG_CONTEXT, true, TAG_FULL_NAME),

                theChoice);

        } else {

            relativeName.encode(theChoice);

            out.writeImplicit(

                DerValue.createTag(DerValue.TAG_CONTEXT, true,

                    TAG_RELATIVE_NAME),

                theChoice);

        }

    }

    /**

     * Compare an object to this distribution point name for equality.

     *

     * @param obj Object to be compared to this

     * @return true if objects match; false otherwise

     */

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof DistributionPointName == false) {

            return false;

        }

        DistributionPointName other = (DistributionPointName)obj;

        return equals(this.fullName, other.fullName) &&

               equals(this.relativeName, other.relativeName);

    }

    /**

     * Returns the hash code for this distribution point name.

     *

     * @return the hash code.

     */

    public int hashCode() {

        int hash = hashCode;

        if (hash == 0) {

            hash = 1;

            if (fullName != null) {

                hash += fullName.hashCode();

            } else {

                hash += relativeName.hashCode();

            }

            hashCode = hash;

        }

        return hash;

    }

    /**

     * Returns a printable string of the distribution point name.

     */

    public String toString() {

        StringBuilder sb = new StringBuilder();

        if (fullName != null) {

            sb.append("DistributionPointName:\n     " + fullName + "\n");

        } else {

            sb.append("DistributionPointName:\n     " + relativeName + "\n");

        }

        return sb.toString();

    }

    /*

     * Utility function for a.equals(b) where both a and b may be null.

     */

    private static boolean equals(Object a, Object b) {

        return (a == null) ? (b == null) : a.equals(b);

    }

}