/**

  * Back 2 Browser Bytecode Translator

  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * 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, version 2 of the License.

  *

  * 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.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://opensource.org/licenses/GPL-2.0.

  */

 package org.apidesign.vm4brwsr;

 import java.io.IOException;

 import java.net.URL;

 import java.util.zip.ZipEntry;

 import java.util.zip.ZipInputStream;

 import org.apidesign.bck2brwsr.core.JavaScriptBody;

 /** Conversion from classpath to load function.

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 final class Zips {

     private Zips() {

     }

     public static void init() {

     }

     public static byte[] loadFromCp(Object[] classpath, String res) {

         for (int i = 0; i < classpath.length; i++) {

             Object c = classpath[i];

             if (c instanceof String) {

                 try {

                     c = classpath[i] = toZip((String)c);

                 } catch (IOException ex) {

                     classpath[i] = ex;

                 }

             }

             if (c instanceof Zips) {

                 Object checkRes = ((Zips)c).findRes(res);

                 if (checkRes instanceof byte[]) {

                     return (byte[])checkRes;

                 }

             }

         }

         return null;

     }

     @JavaScriptBody(args = { "res" }, body = "var r = this[res]; return r ? r : null;")

     private native byte[] findRes(String res);

     @JavaScriptBody(args = { "res", "arr" }, body = "this[res] = arr;")

     private native void putRes(String res, byte[] arr);

     private static Zips toZip(String path) throws IOException {

         URL u = new URL(path);

         ZipInputStream zip = new ZipInputStream(u.openStream());

         Zips z = new Zips();

         for (;;) {

             ZipEntry entry = zip.getNextEntry();

             if (entry == null) {

                 break;

             }

             byte[] arr = new byte[4096];

             int offset = 0;

             for (;;) {

                 int len = zip.read(arr, offset, arr.length - offset);

                 if (len == -1) {

                     break;

                 }

                 offset += len;

                 if (offset == arr.length) {

                     enlargeArray(arr, arr.length + 4096);

                 }

             }

             sliceArray(arr, offset);

             z.putRes(entry.getName(), arr);

         }

         return z;

     }

     @JavaScriptBody(args = { "arr", "len" }, body = "while (arr.length < len) arr.push(0);")

     private static native void enlargeArray(byte[] arr, int len);

     @JavaScriptBody(args = { "arr", "len" }, body = "arr.splice(len, arr.length - len);")

     private static native void sliceArray(byte[] arr, int len);

 }