/**

 * 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.io.InputStream;

import java.net.URL;

import java.util.Enumeration;

/**

 *

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

 */

public final class BytesLoader {

    private static final StringArray requested = new StringArray();

    public byte[] get(String name) throws IOException {

        if (requested.contains(name)) {

            throw new IllegalStateException("Requested for second time: " + name);

        }

        requested.add(name);

        byte[] arr = readClass(name);

        /*

        System.err.print("loader['" + name + "'] = [");

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

        if (i > 0) {

        System.err.print(", ");

        }

        System.err.print(arr[i]);

        }

        System.err.println("]");

         */

        return arr;

    }

    static byte[] readClass(String name) throws IOException {

        URL u = null;

        Enumeration<URL> en = BytesLoader.class.getClassLoader().getResources(name);

        while (en.hasMoreElements()) {

            u = en.nextElement();

        }

        if (u == null) {

            throw new IOException("Can't find " + name);

        }

        try (InputStream is = u.openStream()) {

            byte[] arr;

            arr = new byte[is.available()];

            int offset = 0;

            while (offset < arr.length) {

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

                if (len == -1) {

                    throw new IOException("Can't read " + name);

                }

                offset += len;

            }

            return arr;

        }

    }

}