VoidData.java

// <editor-fold defaultstate="collapsed" desc="license">
/*
 * Copyright (c) 2014, Karl H. Beckers
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * * Neither the name of the <ORGANIZATION> nor the names of its contributors
 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 **/
// </editor-fold>
package net.jarre_de_the.griffin.types.data;

import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Arrays;
import net.jarre_de_the.griffin.Util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Implementation of VOID. The GFF VOID data type contains variable-length
 * arbitrary data. The first element is a DWORD that stores the length of the
 * actual data as a number of bytes.
 *
 * @author charly4711
 */
public class VoidData extends AbstractData
        implements Cloneable {

    private static final Logger LOGGER = LoggerFactory.getLogger(VoidData.class);
    private byte[] value;

    /*
     *
     * constructors
     *
     */
    protected VoidData() {
    }

    /**
     * Creates a new instance of {@code VoidData} from an array of arbitrary
     * bytes.
     *
     * @param buf The value to set.
     * @see #setValue(byte[] buf)
     */
    public VoidData(byte[] buf) {
        setValue(buf);
    }

    /*
     *
     * read from file
     *
     */
    public static VoidData read(RandomAccessFile in)
            throws IOException {
        LOGGER.debug("Reading VoidData from file.");
        DWordData len = DWordData.read(in);
        LOGGER.trace("Need to read " + len.getValueAsNumber() + " bytes.");
        // we're just hoping we'll never encounter a GFF file where a
        // single buffer is > MAXINT
        byte[] buf = new byte[len.getValueAsNumber().intValue()];
        in.readFully(buf);
        LOGGER.trace("Read " + new String(buf, Util.CHARSET_US_ASCII));
        return new VoidData(buf);
    }

    /*
     *
     * setter
     *
     */
    /**
     * Sets this instance's value.
     *
     * @param buf The value to set. This input is copied internally, so don't
     * expect to be able to retain a reference to the array and change it later
     * on.
     */
    private void setValue(byte[] buf) {
        if (buf != null) {
            this.value = new byte[buf.length];
            System.arraycopy(buf, 0, this.value, 0, buf.length);
        }
    }

    /*
     *
     * getter
     *
     */
    /**
     * Retrieves a copy (!) of this instance's value.
     *
     * @return A copy of this instance's value. Changing the copy will NOT
     * change the original.
     */
    public byte[] getValueAsByteArray() {
        byte[] buf;
        if (null != value) {
            buf = new byte[value.length];
            System.arraycopy(value, 0, buf, 0, value.length);
        } else {
            buf = new byte[0];
        }
        return buf;
    }

    /*
     *
     * utility
     *
     */
    /**
     * Overrides the {@code java.lang.Object} method to ensure we always get
     * back an instance of {@code VoidData} rather than just {@code Object}.
     *
     * @return A deep copy of this object.
     * @throws java.lang.CloneNotSupportedException
     */
    @Override
    public VoidData clone() throws CloneNotSupportedException {
        LOGGER.debug("Cloning object");
        VoidData clone = (VoidData) super.clone();
        clone.setValue(value);

        return clone;
    }

    /**
     * Overrides the {@code java.lang.Object} method to make test for equality
     * possible for this class.
     *
     * @param compare The Object to compare this object with.
     * @return True if the objects have the same value, false if not.
     */
    @Override
    public boolean equals(Object compare) {
        if (compare == this) {
            return true;
        }

        if (!(compare instanceof VoidData)) {
            return false;
        }

        VoidData dw = (VoidData) compare;
        return Arrays.equals(dw.getValueAsByteArray(), this.getValueAsByteArray());
    }

    /**
     * Overrides the {@code java.lang.Object} method to ensure we have a hash
     * code consistent with the test for equality.
     *
     * @return The hash returned is based on the value.
     */
    @Override
    public int hashCode() {
        return Arrays.hashCode(value);
    }

}