DWord64Data.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.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import net.jarre_de_the.griffin.Util;
import net.jarre_de_the.griffin.exception.ValueTooLargeException;
import net.jarre_de_the.griffin.exception.ValueTooSmallException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Implementation of the DWORD64. The GFF DWORD64 is an 8 byte unsigned integer
 * with possible values from 0 to 18446744073709551615.
 * <p>
 * @author charly4711
 */
public class DWord64Data extends AbstractFixedLengthData<Long, DWord64Data>
        implements NumberData<BigInteger>, Cloneable {

    /**
     * The length of a DWORD64 in bytes.
     */
    public static final int LENGTH = 8;
    private static final Logger LOGGER = LoggerFactory.getLogger(DWord64Data.class);
    private long value = 0L;

    /*
     *
     * constructors
     *
     */
    protected DWord64Data() {
    }

    /**
     * Creates a new instance of{@code DWord64Data} and sets a defined value.
     * <p>
     * @param l The value to set. The Java primitive long is signed where the
     * DWORD64 is not. Treat this as a bit-field.
     * @see #setValue(long l)
     */
    public DWord64Data(long l) {
        setValue(l);
    }

    /**
     * Creates a new instance of{@code DWord64Data} and sets a defined value.
     * <p>
     * @param bi the numeric representation of the DWord64Data. If you pass a
     * value < 0 or > 0xFFFFFFFFFFFFFFFF, you will get a ValueTooSmallException
     * or ValueTooLargeException runtime exception.
     * @see #setValue(BigInteger bi)
     */
    public DWord64Data(BigInteger bi) {
        setValue(bi);
    }

    /*
     *
     * read from file
     *
     */
    /**
     * Creates a new instance of {@code DWord64Data} based on the data read from
     * the file passed. Note that the contents are read from whatever position
     * the file pointer is at.
     * <p>
     * @param in An open {@code RandomAccessFile}.
     * @return
     * @throws java.io.IOException If there are any I/O related problems with
     * file access to in.
     */
    public static DWord64Data read(RandomAccessFile in)
            throws IOException {
        return new DWord64Data((long) read(in, Long.class));
    }

    /*
     *
     * setter
     *
     */
    /**
     * Sets this instance's value.
     * <p>
     * @param l The value to set. The Java primitive long is signed where the
     * DWORD64 is not. Treat this as a bit-field.
     */
    private void setValue(long l) {
        this.value = l;
    }

    private void setValue(BigInteger bi) {
        BigInteger max = BigInteger.ONE;
        max = max.shiftLeft(64);
        BigInteger minusOne = new BigInteger("-1", 10);
        max = max.add(minusOne);

        if (max.compareTo(bi) < 0) {
            throw new ValueTooLargeException(max, bi);
        } else if (bi.compareTo(BigInteger.ZERO) < 0) {
            throw new ValueTooSmallException(BigInteger.ZERO, bi);
        }

        this.value = bi.longValue();
    }

    /*
     *
     * getter
     *
     */
    /**
     * Returns this instance's value as a long. A DWORD64 is 8 bytes as is the
     * Java long primitive type. However, a DWORD64 is always unsigned and there
     * is no unsigned long in Java. Therefore, the returned value must only be
     * regarded as a bit field.
     * <p>
     * @return The value of this instance as a bit field.
     */
    @Override
    public Long getValue() {
        LOGGER.debug("Retrieving unsigned long to long from: " + value);
        return value;
    }

    @Override
    public BigInteger getValueAsNumber() {
        byte[] buf = new byte[Long.BYTES + 1];
        ByteBuffer bb = ByteBuffer.wrap(buf);
        // this is set to BIG_ENDIAN because that's what the BigInteger
        // constructor expects. It is completely unrelated to the LITTLE_ENDIAN
        // we use elsewhere to get there right format for persisting to GFF.
        bb.order(ByteOrder.BIG_ENDIAN);
        bb.putLong(1, value);
        return new BigInteger(buf);
    }

    /**
     * Returns this instance's value as a byte array in the same order it would
     * be stored in a GFF file.
     * <p>
     * @return This instance's value as a bit field split into 8 bytes.
     */
    @Override
    public byte[] getValueAsByteArray() {
        byte[] buf = new byte[LENGTH];
        ByteBuffer bb = ByteBuffer.wrap(buf);
        bb.order(ByteOrder.LITTLE_ENDIAN);
        bb.putLong(value);
        LOGGER.debug("Retrieving byte array for (" + Long.toHexString(value)
                + ") to: " + new String(buf, Util.CHARSET_US_ASCII));
        return buf;
    }

    /*
     *
     * utility
     *
     */
    @Override
    public int length() {
        return LENGTH;
    }

    /**
     * Overrides the {@code java.lang.Object} method to ensure we always get
     * back an instance of {@code DWord64Data} rather than just {@code Object}.
     * <p>
     * @return A deep copy of this object.
     * @throws java.lang.CloneNotSupportedException
     */
    @Override
    public DWord64Data clone() throws CloneNotSupportedException {
        LOGGER.debug("Cloning object");
        DWord64Data clone = (DWord64Data) super.clone();
        clone.setValue(value);

        return clone;
    }

    /**
     * Overrides the {@code java.lang.Object} method to make test for equality
     * possible for this class.
     * <p>
     * @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 DWord64Data)) {
            return false;
        }

        DWord64Data dw = (DWord64Data) compare;
        if (dw.getValue().equals(this.getValue())) {
            return true;
        }

        return false;
    }

    /**
     * Overrides the {@code java.lang.Object} method to ensure we have a hash
     * code consistent with the test for equality. Because we have a full 8 byte
     * long value but can only return a 4 byte int, we need to lose some date.
     * We do the same as the {@code java.lang.Long}, i. e. return an exclusive
     * OR of the two halves of the long value.
     * <p>
     * <blockquote>
     * {@code (int)(this.getLongValue()^(this.getLongValue()>>>32))}
     * </blockquote>
     * <p>
     * @return The hash returned is based on the value.
     */
    @Override
    public int hashCode() {
        LOGGER.debug("Creating int hashCode from long value");
        long l = getValue();
        return (int) (l ^ (l >>> 32));
    }

    @Override
    public String toString() {
        String iS = Long.toHexString(value);
        if (iS.length() < LENGTH * 2) {
            StringBuilder sb = new StringBuilder();
            sb.append(iS);
            for (int i = 0; i < (LENGTH * 2) - iS.length(); i++) {
                sb.append("0");
            }
            iS = sb.toString();
        }
        return iS;
    }
}