FileUtils.java

/*
 * $Id: FileUtils.java 536 2008-02-19 06:03:27Z weiju $
 * 
 * Created on 2006/02/13
 * Copyright 2005-2008 by Wei-ju Wu
 * This file is part of The Z-machine Preservation Project (ZMPP).
 *
 * ZMPP 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 3 of the License, or
 * (at your option) any later version.
 *
 * ZMPP 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 ZMPP.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.zmpp.vmutil;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.util.ArrayList;
import java.util.List;

import org.zmpp.base.DefaultMemory;
import org.zmpp.base.Memory;
import org.zmpp.blorb.BlorbResources;
import org.zmpp.iff.DefaultFormChunk;
import org.zmpp.iff.FormChunk;
import org.zmpp.media.Resources;

/**
 * This utility class was introduced to avoid a code smell in data
 * initialization. It offers methods to read data from streams and files.
 *
 * @author Wei-ju Wu
 * @version 1.0
 */
public class FileUtils {

    /**
     * This class only contains static methods.
     */
    private FileUtils() {
    }

    /**
     * Creates a resources object from a Blorb file.
     *
     * @param blorbfile the file
     * @return the resources object or null (on failure)
     */
    public static Resources createResources(final File blorbfile) {
        RandomAccessFile raf = null;
        try {
            raf = new RandomAccessFile(blorbfile, "r");
            final byte[] data = new byte[(int) raf.length()];
            raf.readFully(data);
            final Memory memory = new DefaultMemory(data);
            final FormChunk formchunk = new DefaultFormChunk(memory);
            return new BlorbResources(formchunk);
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            if (raf != null) {
                try {
                    raf.close();
                } catch (Exception ex) {
                    ex.printStackTrace(System.err);
                }
            }
        }
        return null;
    }

    /**
     * Reads an array of bytes from the given input stream.
     *
     * @param inputstream the input stream
     * @return the bytes or null if the inputstream is null
     */
    public static byte[] readFileBytes(final InputStream inputstream) {
        byte[] data = null;
        if (inputstream == null) {
            return null;
        }

        try {
            final List<Byte> buffer = new ArrayList<Byte>();
            int databyte = 0;
            do {
                databyte = inputstream.read();
                if (databyte != -1) {
                    buffer.add((byte) databyte);
                }
            } while (databyte != -1);
            data = new byte[buffer.size()];
            for (int i = 0; i < buffer.size(); i++) {
                data[i] = buffer.get(i);
            }
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            try {
                inputstream.close();
            } catch (Exception ex) {
                ex.printStackTrace(System.err);
            }
        }
        return data;
    }

    /**
     * Reads the bytes from the given file if it is a file and it exists.
     *
     * @param file the file object
     * @return a byte array
     */
    public static byte[] readFileBytes(final File file) {
        byte[] data = null;
        if (file != null && file.exists() && file.isFile()) {
            RandomAccessFile raf = null;
            try {
                raf = new RandomAccessFile(file, "r");
                data = new byte[(int) raf.length()];
                raf.readFully(data);
            } catch (IOException ex) {
                ex.printStackTrace();
            } finally {
                if (raf != null) {
                    try {
                        raf.close();
                    } catch (Exception ex) {
                        ex.printStackTrace(System.err);
                    }
                }
            }
        }
        return data;
    }
}