/*
 * Copyright (c) 2009, Oracle and/or its affiliates. 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.security.krb5.internal.util;

import java.io.IOException;
import java.security.AccessController;
import sun.security.action.GetBooleanAction;
import sun.security.util.DerValue;

/**
 * Implements the ASN.1 KerberosString type.
 *
 * <pre>
 * KerberosString  ::= GeneralString (IA5String)
 * </pre>
 *
 * This definition reflects the Network Working Group RFC 4120
 * specification available at
 * <a href="http://www.ietf.org/rfc/rfc4120.txt">
 * http://www.ietf.org/rfc/rfc4120.txt</a>.
 */
public final class KerberosString {
    /**
     * RFC 4120 defines KerberosString as GeneralString (IA5String), which
     * only includes ASCII characters. However, other implementations have been
     * known to use GeneralString to contain UTF-8 encoding. To interop
     * with these implementations, the following system property is defined.
     * When set as true, KerberosString is encoded as UTF-8. Note that this
     * only affects the byte encoding, the tag of the ASN.1 type is still
     * GeneralString.
     */
    public static final boolean MSNAME = AccessController.doPrivileged(
            new GetBooleanAction("sun.security.krb5.msinterop.kstring"));

    private final String s;

    public KerberosString(String s) {
        this.s = s;
    }

    public KerberosString(DerValue der) throws IOException {
        if (der.tag != DerValue.tag_GeneralString) {
            throw new IOException(
                "KerberosString's tag is incorrect: " + der.tag);
        }
        s = new String(der.getDataBytes(), MSNAME?"UTF8":"ASCII");
    }

    public String toString() {
        return s;
    }

    public DerValue toDerValue() throws IOException {
        // No need to cache the result since this method is
        // only called once.
        return new DerValue(DerValue.tag_GeneralString,
                s.getBytes(MSNAME?"UTF8":"ASCII"));
    }
}