/**
 * @(#)ZipImageLoader.java      1.0.1 98/12/04
 * <p>
 * Copyright (C) 1998 David E. Wexler
 * <p>
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. See
 * license.txt for a full copy of the GNU GPL.
 * <p>
 * This program 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 for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 * USA.
 * <p>
 * To Contact the author send e-mail to vagabond@netdragon.com or send
 * snailmail to: 511 Bobcat Ct, Punta Gorda, FL 3398.
 */

import java.applet.Applet;
import java.awt.*;
import java.awt.peer.*;
import java.io.*;
import java.lang.*;
import java.net.*;
import java.util.*;
import java.util.zip.*;

/**
 * ZipImageLoader - Downloads a compressed Zip file and extracts the
 * information into an Image Array.
 * <p>
 * This class is designed to cut dynamic load time by allowing the code
 * developer to zip a large number of images and laod them as arrays
 * in their program.  Not only does this save download time by only
 * requesting one file, the contents can be compressed.
 * <p>
 * @author      David Wexler (vagabond@netdragons.com)
 * @version     1.0.1
 * @since       Nelzan1.0.1
 */


public class ZipImageLoader {

  // Edit this variable depending on the path of your images
  private static final String PATH = "/gfx/";

  Image[] myImages;
  MediaTracker tracker;
  String url;
  Applet comp;

 /**
  * Creates a new Instance of the class, so it can be used later.
  *
  * @param url          Base URL, where all the Zip files are kept.
  * @param c            Instance of an Applet, for call backs.
  */
  public ZipImageLoader(String url, Applet c) {
    this.url = url;
    comp = c;
  }

 /**
  * Downloads a zip file and extracts the contents into an images array.
  * This function also makes use a MediaTracker to make sure the images
  * download and uses CRC32 to make sure the file integrity is good.
  *
  * @param file         The file to download and extract
  * @return            and Image Array with the contents of the Zip File.
  */
  public Image[] getImages(String file) {
    tracker = new MediaTracker(comp);
    myImages = new Image[1];
    int size = 0;
    int downloaded = 0;
    byte buffer[] = new byte[1024];
    ComponentPeer cp = comp.getPeer();
    try {
      URL zipUrl = new URL(url + PATH + file);
      URLConnection conn = zipUrl.openConnection();
      conn.connect();
      DataInputStream stream = new DataInputStream(new
       BufferedInputStream(conn.getInputStream()));
      size = conn.getContentLength();
      ZipInputStream zipStream = new ZipInputStream(stream);
      ZipEntry zipExtract = null;
      while ((zipExtract = zipStream.getNextEntry()) != null) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        long crcReq = zipExtract.getCrc();
        CRC32 crc = new CRC32();
        while (true) {
          int nRead = zipStream.read(buffer, 0, buffer.length);
          if (nRead <= 0)
            break;
          baos.write(buffer, 0, nRead);
          crc.update(buffer, 0, nRead);
        }
        if (crcReq != -1 && crc.getValue() != crcReq) {
          System.out.println("CRC Error extracting file " + zipExtract.getName());
        } else {
          if (downloaded > 0) 
            myImages = addImage(myImages,
             cp.getToolkit().createImage(baos.toByteArray()));
          else
            myImages[0] = cp.getToolkit().createImage(baos.toByteArray());
          tracker.addImage(myImages[myImages.length-1], myImages.length-1);
          downloaded += zipExtract.getCompressedSize();
          StringTokenizer Token = new
           StringTokenizer(zipExtract.getName(), ".", false);
          String name = Token.nextToken();
          byte data[] = baos.toByteArray();
          comp.showStatus("Extracting files from Zip Archive: " + file);
        }
      }
      stream.close();
      zipStream.closeEntry();
    } catch (Exception ex) {
      System.out.println("Exception: " + ex.getMessage());
      ex.printStackTrace();
    }
    comp.showStatus("Verifying files from Zip Archive: " + file);
    try {
      tracker.waitForAll();
    } catch (Exception ex) {
      ex.printStackTrace();
    }
    comp.showStatus("");
    tracker = null;
    return myImages;
  }

 /**
  * Used to Add an Image to the end of an Array.
  *
  * @param ary          The old array.
  * @param im           New Image to add.
  * @return             The new array.
  */
  private Image[] addImage(Image[] ary, Image im) {
    Image[] temp = new Image[ary.length+1];
    for (int i=0; i < ary.length; i++)
      temp[i] = ary[i];
    temp[ary.length] = im;
    System.gc();
    return temp;
  }
}