EncodedArrayItem.java

/*
 * [The "BSD licence"]
 * Copyright (c) 2010 Ben Gruver (JesusFreke)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

package org.jf.dexlib;

import org.jf.dexlib.EncodedValue.ArrayEncodedSubValue;
import org.jf.dexlib.Util.AnnotatedOutput;
import org.jf.dexlib.Util.Input;

public class EncodedArrayItem extends Item<EncodedArrayItem> {
    private int hashCode = 0;

    private ArrayEncodedSubValue encodedArray;

    /**
     * Creates a new uninitialized <code>EncodedArrayItem</code>
     * @param dexFile The <code>DexFile</code> that this item belongs to
     */
    protected EncodedArrayItem(DexFile dexFile) {
        super(dexFile);
    }

    /**
     * Creates a new <code>EncodedArrayItem</code> with the given values
     * @param dexFile The <code>DexFile</code> that this item belongs to
     * @param encodedArray The encoded array value
     */
    private EncodedArrayItem(DexFile dexFile, ArrayEncodedSubValue encodedArray) {
        super(dexFile);
        this.encodedArray = encodedArray;
    }

    /**
     * Returns an <code>EncodedArrayItem</code> for the given values, and that has been interned into the given
     * <code>DexFile</code>
     * @param dexFile The <code>DexFile</code> that this item belongs to
     * @param encodedArray The encoded array value
     * @return an <code>EncodedArrayItem</code> for the given values, and that has been interned into the given
     */
    public static EncodedArrayItem internEncodedArrayItem(DexFile dexFile, ArrayEncodedSubValue encodedArray) {
        EncodedArrayItem encodedArrayItem = new EncodedArrayItem(dexFile, encodedArray);
        return dexFile.EncodedArraysSection.intern(encodedArrayItem);
    }

    /** {@inheritDoc} */
    protected void readItem(Input in, ReadContext readContext) {
        encodedArray = new ArrayEncodedSubValue(dexFile, in);
    }

    /** {@inheritDoc} */
    protected int placeItem(int offset) {
        return encodedArray.placeValue(offset);
    }

    /** {@inheritDoc} */
    protected void writeItem(AnnotatedOutput out) {
        encodedArray.writeValue(out);
    }

    /** {@inheritDoc} */
    public ItemType getItemType() {
        return ItemType.TYPE_ENCODED_ARRAY_ITEM;
    }

    /** {@inheritDoc} */
    public String getConciseIdentity() {
        return "encoded_array @0x" + Integer.toHexString(getOffset());
    }

    /** {@inheritDoc} */
    public int compareTo(EncodedArrayItem encodedArrayItem) {
        return encodedArray.compareTo(encodedArrayItem.encodedArray);
    }

    /**
     * @return The encoded array value
     */
    public ArrayEncodedSubValue getEncodedArray() {
        return encodedArray;
    }

    /**
     * calculate and cache the hashcode
     */
    private void calcHashCode() {
        hashCode = encodedArray.hashCode();
    }

    @Override
    public int hashCode() {
        //there's a small possibility that the actual hash code will be 0. If so, we'll
        //just end up recalculating it each time
        if (hashCode == 0)
            calcHashCode();
        return hashCode;
    }

    @Override
    public boolean equals(Object o) {
        if (this==o) {
            return true;
        }
        if (o==null || !this.getClass().equals(o.getClass())) {
            return false;
        }

        EncodedArrayItem other = (EncodedArrayItem)o;
        return (encodedArray.compareTo(other.encodedArray) == 0);
    }
}