hexdump sample

hexdump_sample.java

// -*- mode: java; coding: utf-8 -*-
//
// Time-stamp: <2021-10-22 09:12:02 norim>
// 
// TODO: echo server を作成、任意のデータを受信すると、それをhexdump して返信
import java.io.*;
import java.net.*;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

// byte[] b = "Morning".getBytes(StandardCharsets.UTF_8);     //byte array   
// String string = new String(b, StandardCharsets.UTF_8);   //string with "UTF-8" encoding

class receiver {

    //
    // TODO: StringBufferかDataOutoutStreamに出力する版を作成
    //
    public static void hexdump(byte[] binIn){
	final int BYTES_PER_LINE = 16;
	StringBuffer sb = new StringBuffer();
	byte[] binDup   = new byte[BYTES_PER_LINE];
	
        for (int i = 0; binIn.length > i; i++) {
	    if ((sb.length()>0)) {
		if ((i % BYTES_PER_LINE) == 0){
		    String ascii = new String(binDup, java.nio.charset.StandardCharsets.UTF_8);
		    String addrs = String.format("%08x", i);
		    System.out.println(addrs + ": "+ sb.toString() + " " + ascii);
		    sb.delete(0, sb.length());
		}
		else {
		    sb.append(" ");
		}
	    }
	    sb.append(String.format("%02x", binIn[i] & 0xff));
	    if (((binIn[i] & 0xff) > 31) && ((binIn[i] & 0xff) < 64)){
		binDup[i % BYTES_PER_LINE] = binIn[i];
	    }
	    else {
		binDup[i % BYTES_PER_LINE] = 45;
	    }
		
        }
	sb.delete(0, sb.length());

    }
    
    public static byte[] sample(){
	final int MAGIC   = 0x12; // 1234; // 0x04D2
	final int VERSION = 0x34; // 5678; // 0x162E
	// final byte [] CODE = new byte
	DataOutputStream in = null;
	ByteArrayOutputStream bIn = new ByteArrayOutputStream(100);
	try {
	    in = new DataOutputStream(bIn);
	    in.write(MAGIC);
	    in.write(VERSION);
	    in.writeShort(1); // max_stack
	    in.writeShort(1); // max_locals
	    for (int i=1; i<50; i++){
		in.writeShort(i);
	    }
	    // in.writeInt(CODE.length); // code length
	    // in.write(CODE);
	    if(in != null) {
		try {
		    in.close();
		} catch (IOException e) {
		    // throw new ObjenesisException(e);
		    // return bIn.toByteArray();
		    return null;
		}
	    }
	} catch (IOException e) {
	    // throw new ObjenesisException(e);
	} finally {
	    if(in != null) {
		try {
		    in.close();
		} catch (IOException e) {
		    //throw new ObjenesisException(e);
		}
	    }
	}

	return bIn.toByteArray();
    }
    
    public static void main(String args[]) throws Exception {
	// DatagramSocket serverSocket = new DatagramSocket(1024); // port# : 1024
	// byte[] receiveData = new byte[1024];
	// byte[] sendData = new byte[1024];
	// System.out.println("Listening...");

	byte[] result = sample();
	hexdump(result);
	// while(true){
	//     DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
	//     serverSocket.receive(receivePacket);
	//     // double data = ByteBuffer.wrap(receiveData).getDouble();
	//     ByteBuffer  bb = ByteBuffer.wrap(receivePacket.getData(), 0, receivePacket.getLength());
	//     bb.order(ByteOrder.LITTLE_ENDIAN);
	//     double data = bb.getDouble();
	//     System.out.println(data);
	// InetSocketAddress answerAddr = new InetSocketAddress("localhost",10005);
	// DatagramPacket sendPacket = new DatagramPacket(data, data.length, anwserAddr);
	// serverSocket.send(sendPacket);
	// }
	serverSocket.close();

	
    }
}