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/* * Copyright (c) 1998, 2003, 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 com.sun.tools.jdi; import com.sun.jdi.*;import java.io.IOException; public class Packet extends Object {    public final static short NoFlags = 0x0;    public final static short Reply = 0x80;    public final static short ReplyNoError = 0x0;     static int uID = 1;    final static byte[] nullData = new byte[0];     // Note! flags, cmdSet, and cmd are all byte values.    // We represent them as shorts to make them easier    // to work with.    int id;    short flags;    short cmdSet;    short cmd;    short errorCode;    byte[] data;    volatile boolean replied = false;     /**     * Return byte representation of the packet     */    public byte[] toByteArray() {        int len = data.length + 11;        byte b[] = new byte[len];        b[0] = (byte)((len >>> 24) & 0xff);        b[1] = (byte)((len >>> 16) & 0xff);        b[2] = (byte)((len >>>  8) & 0xff);        b[3] = (byte)((len >>>  0) & 0xff);        b[4] = (byte)((id >>> 24) & 0xff);        b[5] = (byte)((id >>> 16) & 0xff);        b[6] = (byte)((id >>>  8) & 0xff);        b[7] = (byte)((id >>>  0) & 0xff);        b[8] = (byte)flags;        if ((flags & Packet.Reply) == 0) {            b[9] = (byte)cmdSet;            b[10] = (byte)cmd;        } else {            b[9] = (byte)((errorCode >>>  8) & 0xff);            b[10] = (byte)((errorCode >>>  0) & 0xff);        }        if (data.length > 0) {            System.arraycopy(data, 0, b, 11, data.length);        }        return b;    }     /**     * Create a packet from its byte array representation     */    public static Packet fromByteArray(byte b[]) throws IOException {        if (b.length < 11) {            throw new IOException("packet is insufficient size");        }         int b0 = b[0] & 0xff;        int b1 = b[1] & 0xff;        int b2 = b[2] & 0xff;        int b3 = b[3] & 0xff;        int len = ((b0 << 24) | (b1 << 16) | (b2 << 8) | (b3 << 0));        if (len != b.length) {            throw new IOException("length size mis-match");        }         int b4 = b[4] & 0xff;        int b5 = b[5] & 0xff;        int b6 = b[6] & 0xff;        int b7 = b[7] & 0xff;         Packet p = new Packet();        p.id = ((b4 << 24) | (b5 << 16) | (b6 << 8) | (b7 << 0));         p.flags = (short)(b[8] & 0xff);         if ((p.flags & Packet.Reply) == 0) {            p.cmdSet = (short)(b[9] & 0xff);            p.cmd = (short)(b[10] & 0xff);        } else {            short b9 = (short)(b[9] & 0xff);            short b10 = (short)(b[10] & 0xff);            p.errorCode = (short)((b9 << 8) + (b10 << 0));        }         p.data = new byte[b.length - 11];        System.arraycopy(b, 11, p.data, 0, p.data.length);        return p;    }     Packet()    {        id = uniqID();        flags = NoFlags;        data = nullData;    }     static synchronized private int uniqID()    {        /*         * JDWP spec does not require this id to be sequential and         * increasing, but our implementation does. See         * VirtualMachine.notifySuspend, for example.         */        return uID++;    }}