// Copyright (C) 2002 IAIK
// https://sic.tech/
//
// Copyright (C) 2003 - 2025 Stiftung Secure Information and 
//                           Communication Technologies SIC
// https://sic.tech/
//
// All rights reserved.
//
// This source is provided for inspection purposes and recompilation only,
// unless specified differently in a contract with IAIK. This source has to
// be kept in strict confidence and must not be disclosed to any third party
// under any circumstances. Redistribution in source and binary forms, with
// or without modification, are <not> permitted in any case!
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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// $Header: /IAIK-CMS/current/src/demo/cms/data/DataOutputStreamDemo.java 6     12.02.25 17:58 Dbratko $
// $Revision: 6 $
//

package demo.cms.data;

import iaik.asn1.ObjectID;
import iaik.cms.CMSException;
import iaik.cms.ContentInfoOutputStream;
import iaik.cms.DataOutputStream;
import iaik.cms.DataStream;
import iaik.utils.Util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import demo.DemoUtil;

/**
 * Demonstrates the usage of class {@link iaik.cms.DataOutputStream}.
 */
public class DataOutputStreamDemo {

  /**
   * Default constructor.
   */
  public DataOutputStreamDemo() throws IOException {
    System.out.println();
    System.out.println("**********************************************************************************");
    System.out.println("*                          DataOutputStream demo                                 *");
    System.out.println("*           (shows the usage of the DataOutputStream implementation)             *");
    System.out.println("**********************************************************************************");
    System.out.println();
  }


  /**
   * Uses the IAIK-CMS DataOutputStream class to encode the given data.
   * 
   * @param message the message to be encoded, as byte representation
   * 
   * @return the BER encoding of the <code>Data</code> object just created,
   *         wrapped in a ContentInfo
   * 
   * @throws CMSException if the <code>Data</code> object cannot
   *                          be created
   * @throws IOException if an I/O error occurs
   */
  public byte[] createData(byte[] message) throws CMSException, IOException  {

    System.out.println("Create a new Data message:");

    // the stream from which to read the content
    ByteArrayInputStream is = new ByteArrayInputStream(message);

    // the stream to which to write the Data object
    ByteArrayOutputStream resultStream = new ByteArrayOutputStream();
    
    // wrap Data into a ContentInfo 
    ContentInfoOutputStream contentInfoStream = 
      new ContentInfoOutputStream(ObjectID.cms_data, resultStream);
    // create a new DataOutputStream object 
    DataOutputStream data = new DataOutputStream(contentInfoStream);


    int blockSize = 8; // in real world we would use a block size like 2048
    //  write the data 
    byte[] buffer = new byte[blockSize];
    int bytesRead;
    while ((bytesRead = is.read(buffer)) != -1) {
      data.write(buffer, 0, bytesRead);
    }
    
    // closing the stream 
    data.close();
    return resultStream.toByteArray();
  }

  /**
   * Parses a CMS <code>Data</code> object.
   *
   * @param data the <code>Data</code> object as BER encoded byte array
   *
   * @return the inherent content as byte array
   *
   * @throws CMSException if an parsing exception occurs
   * @throws IOException if an I/O error occurs
   */
  public byte[] getData(byte[] data) throws CMSException, IOException {

    // we are testing the stream interface
    ByteArrayInputStream is = new ByteArrayInputStream(data);
    // create the Data object
    DataStream dataStream = new DataStream(is);

    // get an InputStream for reading the signed content
    InputStream content = dataStream.getInputStream();
    ByteArrayOutputStream os = new ByteArrayOutputStream();
    Util.copyStream(content, os, null);

    return os.toByteArray();
  }


  
  /**
   * Starts the tests.
   */
  public void start() {
     // the test message
    String m = "This is the test message.";
    System.out.println("Test message: \""+m+"\"");
    System.out.println();
    byte[] message = m.getBytes();

    try {
      byte[] encoding;
      byte[] received_message = null;
      
      System.out.println("\nDataOutputStream demo [create]:\n");
      encoding = createData(message);
      // transmit data
      System.out.println("\nDataOutputStream demo [parse]:\n");
      received_message = getData(encoding);
      System.out.print("\nContent: ");
      System.out.println(new String(received_message));

        } catch (Exception ex) {
          ex.printStackTrace();
          throw new RuntimeException(ex.toString());
        }
  }

  /**
   * Main method.
   */
  public static void main(String argv[]) throws Exception {

        DemoUtil.initDemos();

    (new DataOutputStreamDemo()).start();
    System.out.println("\nReady!");
    DemoUtil.waitKey();
  }
}