1/* 2 * Copyright 2012, Google Inc. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: 8 * 9 * * Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * * Redistributions in binary form must reproduce the above 12 * copyright notice, this list of conditions and the following disclaimer 13 * in the documentation and/or other materials provided with the 14 * distribution. 15 * * Neither the name of Google Inc. nor the names of its 16 * contributors may be used to endorse or promote products derived from 17 * this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32package org.jf.dexlib2.dexbacked.util; 33 34import org.jf.dexlib2.dexbacked.DexBackedDexFile; 35import org.jf.dexlib2.dexbacked.DexReader; 36 37import javax.annotation.Nonnull; 38import java.util.ListIterator; 39import java.util.NoSuchElementException; 40 41public abstract class VariableSizeListIterator<T> implements ListIterator<T> { 42 @Nonnull private DexReader reader; 43 protected final int size; 44 private final int startOffset; 45 46 private int index; 47 48 protected VariableSizeListIterator(@Nonnull DexBackedDexFile dexFile, int offset, int size) { 49 this.reader = dexFile.readerAt(offset); 50 this.startOffset = offset; 51 this.size = size; 52 } 53 54 /** 55 * Reads the next item from reader. 56 * 57 * @param reader The {@code DexReader} to read the next item from 58 * @param index The index of the item being read. This is guaranteed to be less than {@code size} 59 * @return The item that was read 60 */ 61 protected abstract T readNextItem(@Nonnull DexReader reader, int index); 62 63 public int getReaderOffset() { 64 return reader.getOffset(); 65 } 66 67 @Override 68 public boolean hasNext() { 69 return index < size; 70 } 71 72 @Override 73 public T next() { 74 if (index >= size) { 75 throw new NoSuchElementException(); 76 } 77 return readNextItem(reader, index++); 78 } 79 80 @Override 81 public boolean hasPrevious() { 82 return index > 0; 83 } 84 85 @Override 86 public T previous() { 87 int targetIndex = index-1; 88 reader.setOffset(startOffset); 89 index = 0; 90 while (index < targetIndex) { 91 readNextItem(reader, index++); 92 } 93 return readNextItem(reader, index++); 94 } 95 96 @Override 97 public int nextIndex() { 98 return index; 99 } 100 101 @Override 102 public int previousIndex() { 103 return index - 1; 104 } 105 106 @Override public void remove() { throw new UnsupportedOperationException(); } 107 @Override public void set(T t) { throw new UnsupportedOperationException(); } 108 @Override public void add(T t) { throw new UnsupportedOperationException(); } 109} 110