/*

 * Copyright (c) 2010, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.lang;

import java.io.DataInputStream;

import java.io.InputStream;

import java.lang.ref.SoftReference;

import java.util.Arrays;

import java.util.zip.InflaterInputStream;

import java.security.AccessController;

import java.security.PrivilegedAction;

class CharacterName {

    private static SoftReference<byte[]> refStrPool;

    private static int[][] lookup;

    private static synchronized byte[] initNamePool() {

        byte[] strPool = null;

        if (refStrPool != null && (strPool = refStrPool.get()) != null)

            return strPool;

        DataInputStream dis = null;

        try {

            dis = new DataInputStream(new InflaterInputStream(

                AccessController.doPrivileged(new PrivilegedAction<InputStream>()

                {

                    public InputStream run() {

                        return getClass().getResourceAsStream("uniName.dat");

                    }

                })));

            lookup = new int[(Character.MAX_CODE_POINT + 1) >> 8][];

            int total = dis.readInt();

            int cpEnd = dis.readInt();

            byte ba[] = new byte[cpEnd];

            dis.readFully(ba);

            int nameOff = 0;

            int cpOff = 0;

            int cp = 0;

            do {

                int len = ba[cpOff++] & 0xff;

                if (len == 0) {

                    len = ba[cpOff++] & 0xff;

                    // always big-endian

                    cp = ((ba[cpOff++] & 0xff) << 16) |

                         ((ba[cpOff++] & 0xff) <<  8) |

                         ((ba[cpOff++] & 0xff));

                }  else {

                    cp++;

                }

                int hi = cp >> 8;

                if (lookup[hi] == null) {

                    lookup[hi] = new int[0x100];

                }

                lookup[hi][cp&0xff] = (nameOff << 8) | len;

                nameOff += len;

            } while (cpOff < cpEnd);

            strPool = new byte[total - cpEnd];

            dis.readFully(strPool);

            refStrPool = new SoftReference<>(strPool);

        } catch (Exception x) {

            throw new InternalError(x.getMessage());

        } finally {

            try {

                if (dis != null)

                    dis.close();

            } catch (Exception xx) {}

        }

        return strPool;

    }

    public static String get(int cp) {

        byte[] strPool = null;

        if (refStrPool == null || (strPool = refStrPool.get()) == null)

            strPool = initNamePool();

        int off = 0;

        if (lookup[cp>>8] == null ||

            (off = lookup[cp>>8][cp&0xff]) == 0)

            return null;

        return new String(strPool, 0, off >>> 8, off & 0xff);  // ASCII

    }

}