/*
Generic Threads for Asynchronous Read/Write (binary)
*/
import java.io.*;
import java.net.Socket; // for sample main only

class AsynchRead extends Thread  //implements Runnable
{
    protected DataInputStream din;
    protected byte[] buffer; // pointer to external buffer
    protected int si; // starting index to read into
    protected int len; // number of bytes to read
    public AsynchRead(DataInputStream d, byte[] b, int i, int l)
    {
	din=d;  buffer = b;  si=i;  len=l; 
    }
    public void run()
    {
	try
	    {
		int n = 0;
		while (n<len)
		    n += din.read(buffer,si,len-n);
	    }
	catch(IOException ie) {System.out.println(ie);}
    }//run
}//AsynchRead


class AsynchWrite implements Runnable
{
    protected DataOutputStream dout;
    protected byte[] buffer; // pointer to external buffer
    protected int si; // starting index to write from
    protected int len; // number of bytes to write
    public AsynchWrite(DataOutputStream d, byte[] b, int i, int l)
    {
	dout=d;  buffer = b;  si=i;  len=l; 
    }
    public void run()
    {
	try
	    {
		dout.write(buffer,si,len);
	    }
	catch(IOException ie) {System.out.println(ie);}
    }//run
}//AsynchRead


/* sample usage

public class asynch
{
    public static void main(String[] av) throws Exception
    {
	byte[] readBuf = new byte[2048];
	byte[] writeBuf = new byte[2048];
	Socket cfd = new Socket(av[0],Integer.parseInt(av[1]));
	DataInputStream din = new DataInputStream(cfd.getInputStream());
	DataOutputStream dout = new DataOutputStream(cfd.getOutputStream());
	Thread readthread = new AsynchRead(din,readBuf,0,readBuf.length);
	readthread.start(); // start to read
	// prepare write buffer in the meantime, generate some data to write
	for(int i=0;i<writeBuf.length;i++) writeBuf[i]=(byte)(i*2);  
	Thread writethread = new Thread(new AsynchWrite(dout,writeBuf,0,2048));
	writethread.start();
	readthread.join();
	writethread.join();
    }//main
}

*/