streamsource.java

传感器网络中的嵌入式操作系统源代码

// $Id: StreamSource.java,v 1.8.2.2 2003/08/18 22:09:43 cssharp Exp $

/*									tab:4
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 * Copyright (c) 2002-2003 Intel Corporation
 * All rights reserved.
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 * file. If you do not find these files, copies can be found by writing to
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package net.tinyos.packet;

import java.io.*;

/**
 * The old, broken, serial-forwarder protocol on an arbitrary stream
 */
abstract class StreamSource extends AbstractSource
{
    protected InputStream is;
    protected OutputStream os;
    protected int packetSize;

    protected StreamSource(String name, int packetSize) {
	super(name);
	this.packetSize = packetSize;
    }

    protected byte[] readSourcePacket() throws IOException {
	byte[] packet = new byte[packetSize];
	int offset = 0;

	while (offset < packetSize) {
	  int count = is.read(packet, offset, packetSize - offset);

	  if (count == -1)
	    throw new IOException("end-of-stream");
	  offset += count;
	}
	return BrokenPacketizer.collapsePacket(packet);
    }

    protected boolean writeSourcePacket(byte[] packet) throws IOException {
	os.write(BrokenPacketizer.expandPacket(packet, packetSize));
	return true;
    }
}