VariableSizeList.java revision be799799ff8bbc5d86f8cfdc850947ab4f41695f 
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.DexFile;
35import org.jf.dexlib2.DexFileReader;
36import org.jf.util.AbstractListIterator;
37
38import java.util.AbstractSequentialList;
39import java.util.NoSuchElementException;
40
41/**
42 * Provides a base class for a list that is backed by variable size items in a dex file
43 * @param <T> The type of the item that this list contains
44 */
45public abstract class VariableSizeList<T> extends AbstractSequentialList<T> {
46    private final DexFile dexFile;
47    private final int offset;
48
49    public VariableSizeList(DexFile dexFile, int offset) {
50        this.dexFile = dexFile;
51        this.offset = offset;
52    }
53
54    protected abstract T readItem(DexFileReader dexFileReader, int index);
55
56    protected void skipItem(DexFileReader dexFileReader, int index) {
57        readItem(dexFileReader, index);
58    }
59
60    @Override
61    public Iterator listIterator(int startIndex) {
62        Iterator iterator = listIterator();
63        if (startIndex < 0 || startIndex >= size()) {
64            throw new IndexOutOfBoundsException();
65        }
66        for (int i=0; i<startIndex; i++) {
67            iterator.skip();
68        }
69        return iterator;
70    }
71
72    @Override
73    public Iterator listIterator() {
74        return new Iterator();
75    }
76
77    public class Iterator extends AbstractListIterator<T> {
78        private int index = 0;
79        private final DexFileReader dexFileReader = dexFile.readerAt(offset);
80
81        @Override public boolean hasNext() { return index < size(); }
82        @Override public int nextIndex() { return index; }
83
84        @Override
85        public T next() {
86            if (index >= size()) {
87                throw new NoSuchElementException();
88            }
89            return readItem(dexFileReader, index++);
90        }
91
92        public void skip() {
93            if (index >= size()) {
94                throw new NoSuchElementException();
95            }
96            skipItem(dexFileReader, index++);
97        }
98    }
99}
100