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 29package org.jf.dexlib; 30 31import org.jf.dexlib.Util.AnnotatedOutput; 32import org.jf.dexlib.Util.Input; 33import org.jf.dexlib.Util.Leb128Utils; 34import org.jf.dexlib.Util.Utf8Utils; 35 36public class StringDataItem extends Item<StringDataItem> { 37 private int hashCode = 0; 38 39 private String stringValue; 40 41 /** 42 * Creates a new uninitialized <code>StringDataItem</code> 43 * @param dexFile The <code>DexFile</code> that this item belongs to 44 */ 45 protected StringDataItem(DexFile dexFile) { 46 super(dexFile); 47 } 48 49 /** 50 * Creates a new <code>StringDataItem</code> for the given string 51 * @param dexFile The <code>DexFile</code> that this item belongs to 52 * @param stringValue The string value that this item represents 53 */ 54 private StringDataItem(DexFile dexFile, String stringValue) { 55 super(dexFile); 56 57 this.stringValue = stringValue; 58 } 59 60 /** 61 * Returns a <code>StringDataItem</code> for the given values, and that has been interned into 62 * the given <code>DexFile</code> 63 * @param dexFile The <code>DexFile</code> that this item belongs to 64 * @param value The string value that this item represents 65 * @return a <code>StringDataItem</code> for the given values, and that has been interned into 66 * the given <code>DexFile</code> 67 */ 68 public static StringDataItem internStringDataItem(DexFile dexFile, String value) { 69 StringDataItem StringDataItem = new StringDataItem(dexFile, value); 70 return dexFile.StringDataSection.intern(StringDataItem); 71 } 72 73 /** 74 * Looks up the <code>StringDataItem</code> from the given <code>DexFile</code> for the given 75 * string value 76 * @param dexFile the <code>Dexfile</code> to find the string value in 77 * @param value The string value to look up 78 * @return a <code>StringDataItem</code> from the given <code>DexFile</code> for the given 79 * string value, or null if it doesn't exist 80 **/ 81 public static StringDataItem lookupStringDataItem(DexFile dexFile, String value) { 82 StringDataItem StringDataItem = new StringDataItem(dexFile, value); 83 return dexFile.StringDataSection.getInternedItem(StringDataItem); 84 } 85 86 /** {@inheritDoc} */ 87 protected void readItem(Input in, ReadContext readContext) { 88 in.readUnsignedLeb128(); //string length 89 stringValue = in.realNullTerminatedUtf8String(); 90 } 91 92 /** {@inheritDoc} */ 93 protected int placeItem(int offset) { 94 return offset + Leb128Utils.unsignedLeb128Size(stringValue.length()) + 95 Utf8Utils.stringToUtf8Bytes(stringValue).length + 1; 96 } 97 98 /** {@inheritDoc} */ 99 protected void writeItem(AnnotatedOutput out) { 100 byte[] encodedValue = Utf8Utils.stringToUtf8Bytes(stringValue); 101 if (out.annotates()) { 102 out.annotate("string_size: 0x" + Integer.toHexString(stringValue.length()) + " (" + stringValue.length() + 103 ")"); 104 out.writeUnsignedLeb128(stringValue.length()); 105 106 out.annotate(encodedValue.length + 1, "string_data: \"" + Utf8Utils.escapeString(stringValue) + "\""); 107 } else { 108 out.writeUnsignedLeb128(stringValue.length()); 109 } 110 out.write(encodedValue); 111 out.writeByte(0); 112 } 113 114 /** {@inheritDoc} */ 115 public ItemType getItemType() { 116 return ItemType.TYPE_STRING_DATA_ITEM; 117 } 118 119 /** {@inheritDoc} */ 120 public String getConciseIdentity() { 121 return "string_data_item: \"" + Utf8Utils.escapeString(getStringValue()) + "\""; 122 } 123 124 /** {@inheritDoc} */ 125 public int compareTo(StringDataItem o) { 126 return getStringValue().compareTo(o.getStringValue()); 127 } 128 129 /** 130 * Get the string value of this item as a <code>String</code> 131 * @return the string value of this item as a String 132 */ 133 public String getStringValue() { 134 return stringValue; 135 } 136 137 /** 138 * calculate and cache the hashcode 139 */ 140 private void calcHashCode() { 141 hashCode = getStringValue().hashCode(); 142 } 143 144 @Override 145 public int hashCode() { 146 //there's a small possibility that the actual hash code will be 0. If so, we'll 147 //just end up recalculating it each time 148 if (hashCode == 0) 149 calcHashCode(); 150 return hashCode; 151 } 152 153 @Override 154 public boolean equals(Object o) { 155 if (this==o) { 156 return true; 157 } 158 if (o==null || !this.getClass().equals(o.getClass())) { 159 return false; 160 } 161 162 //This assumes that the referenced items have been interned in both objects. 163 //This is a valid assumption because all outside code must use the static 164 //"getInterned..." style methods to make new items, and any item created 165 //internally is guaranteed to be interned 166 StringDataItem other = (StringDataItem)o; 167 return getStringValue().equals(other.getStringValue()); 168 } 169} 170