/*
 * Copyright (c) 1998, 2003, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.
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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
/** * 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
/** * 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++; } }