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      1 /*
      2  * [The "BSD licence"]
      3  * Copyright (c) 2010 Ben Gruver (JesusFreke)
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. The name of the author may not be used to endorse or promote products
     15  *    derived from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 package org.jf.dexlib;
     30 
     31 import org.jf.dexlib.EncodedValue.ArrayEncodedSubValue;
     32 import org.jf.dexlib.Util.AnnotatedOutput;
     33 import org.jf.dexlib.Util.Input;
     34 
     35 public class EncodedArrayItem extends Item<EncodedArrayItem> {
     36     private int hashCode = 0;
     37 
     38     private ArrayEncodedSubValue encodedArray;
     39 
     40     /**
     41      * Creates a new uninitialized <code>EncodedArrayItem</code>
     42      * @param dexFile The <code>DexFile</code> that this item belongs to
     43      */
     44     protected EncodedArrayItem(DexFile dexFile) {
     45         super(dexFile);
     46     }
     47 
     48     /**
     49      * Creates a new <code>EncodedArrayItem</code> with the given values
     50      * @param dexFile The <code>DexFile</code> that this item belongs to
     51      * @param encodedArray The encoded array value
     52      */
     53     private EncodedArrayItem(DexFile dexFile, ArrayEncodedSubValue encodedArray) {
     54         super(dexFile);
     55         this.encodedArray = encodedArray;
     56     }
     57 
     58     /**
     59      * Returns an <code>EncodedArrayItem</code> for the given values, and that has been interned into the given
     60      * <code>DexFile</code>
     61      * @param dexFile The <code>DexFile</code> that this item belongs to
     62      * @param encodedArray The encoded array value
     63      * @return an <code>EncodedArrayItem</code> for the given values, and that has been interned into the given
     64      */
     65     public static EncodedArrayItem internEncodedArrayItem(DexFile dexFile, ArrayEncodedSubValue encodedArray) {
     66         EncodedArrayItem encodedArrayItem = new EncodedArrayItem(dexFile, encodedArray);
     67         return dexFile.EncodedArraysSection.intern(encodedArrayItem);
     68     }
     69 
     70     /** {@inheritDoc} */
     71     protected void readItem(Input in, ReadContext readContext) {
     72         encodedArray = new ArrayEncodedSubValue(dexFile, in);
     73     }
     74 
     75     /** {@inheritDoc} */
     76     protected int placeItem(int offset) {
     77         return encodedArray.placeValue(offset);
     78     }
     79 
     80     /** {@inheritDoc} */
     81     protected void writeItem(AnnotatedOutput out) {
     82         encodedArray.writeValue(out);
     83     }
     84 
     85     /** {@inheritDoc} */
     86     public ItemType getItemType() {
     87         return ItemType.TYPE_ENCODED_ARRAY_ITEM;
     88     }
     89 
     90     /** {@inheritDoc} */
     91     public String getConciseIdentity() {
     92         return "encoded_array @0x" + Integer.toHexString(getOffset());
     93     }
     94 
     95     /** {@inheritDoc} */
     96     public int compareTo(EncodedArrayItem encodedArrayItem) {
     97         return encodedArray.compareTo(encodedArrayItem.encodedArray);
     98     }
     99 
    100     /**
    101      * @return The encoded array value
    102      */
    103     public ArrayEncodedSubValue getEncodedArray() {
    104         return encodedArray;
    105     }
    106 
    107     /**
    108      * calculate and cache the hashcode
    109      */
    110     private void calcHashCode() {
    111         hashCode = encodedArray.hashCode();
    112     }
    113 
    114     @Override
    115     public int hashCode() {
    116         //there's a small possibility that the actual hash code will be 0. If so, we'll
    117         //just end up recalculating it each time
    118         if (hashCode == 0)
    119             calcHashCode();
    120         return hashCode;
    121     }
    122 
    123     @Override
    124     public boolean equals(Object o) {
    125         if (this==o) {
    126             return true;
    127         }
    128         if (o==null || !this.getClass().equals(o.getClass())) {
    129             return false;
    130         }
    131 
    132         EncodedArrayItem other = (EncodedArrayItem)o;
    133         return (encodedArray.compareTo(other.encodedArray) == 0);
    134     }
    135 }
    136