1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.dex;
18
19import java.io.IOException;
20import java.io.UnsupportedEncodingException;
21import java.util.Arrays;
22
23/**
24 * The file header and map.
25 */
26public final class TableOfContents {
27
28    /*
29     * TODO: factor out ID constants.
30     */
31
32    public final Section header = new Section(0x0000);
33    public final Section stringIds = new Section(0x0001);
34    public final Section typeIds = new Section(0x0002);
35    public final Section protoIds = new Section(0x0003);
36    public final Section fieldIds = new Section(0x0004);
37    public final Section methodIds = new Section(0x0005);
38    public final Section classDefs = new Section(0x0006);
39    public final Section mapList = new Section(0x1000);
40    public final Section typeLists = new Section(0x1001);
41    public final Section annotationSetRefLists = new Section(0x1002);
42    public final Section annotationSets = new Section(0x1003);
43    public final Section classDatas = new Section(0x2000);
44    public final Section codes = new Section(0x2001);
45    public final Section stringDatas = new Section(0x2002);
46    public final Section debugInfos = new Section(0x2003);
47    public final Section annotations = new Section(0x2004);
48    public final Section encodedArrays = new Section(0x2005);
49    public final Section annotationsDirectories = new Section(0x2006);
50    public final Section[] sections = {
51            header, stringIds, typeIds, protoIds, fieldIds, methodIds, classDefs, mapList,
52            typeLists, annotationSetRefLists, annotationSets, classDatas, codes, stringDatas,
53            debugInfos, annotations, encodedArrays, annotationsDirectories
54    };
55
56    public int apiLevel;
57    public int checksum;
58    public byte[] signature;
59    public int fileSize;
60    public int linkSize;
61    public int linkOff;
62    public int dataSize;
63    public int dataOff;
64
65    public TableOfContents() {
66        signature = new byte[20];
67    }
68
69    public void readFrom(Dex dex) throws IOException {
70        readHeader(dex.open(0));
71        readMap(dex.open(mapList.off));
72        computeSizesFromOffsets();
73    }
74
75    private void readHeader(Dex.Section headerIn) throws UnsupportedEncodingException {
76        byte[] magic = headerIn.readByteArray(8);
77
78        if (!DexFormat.isSupportedDexMagic(magic)) {
79            throw new DexException("Unexpected magic: " + Arrays.toString(magic));
80        }
81
82        apiLevel = DexFormat.magicToApi(magic);
83        checksum = headerIn.readInt();
84        signature = headerIn.readByteArray(20);
85        fileSize = headerIn.readInt();
86        int headerSize = headerIn.readInt();
87        if (headerSize != SizeOf.HEADER_ITEM) {
88            throw new DexException("Unexpected header: 0x" + Integer.toHexString(headerSize));
89        }
90        int endianTag = headerIn.readInt();
91        if (endianTag != DexFormat.ENDIAN_TAG) {
92            throw new DexException("Unexpected endian tag: 0x" + Integer.toHexString(endianTag));
93        }
94        linkSize = headerIn.readInt();
95        linkOff = headerIn.readInt();
96        mapList.off = headerIn.readInt();
97        if (mapList.off == 0) {
98            throw new DexException("Cannot merge dex files that do not contain a map");
99        }
100        stringIds.size = headerIn.readInt();
101        stringIds.off = headerIn.readInt();
102        typeIds.size = headerIn.readInt();
103        typeIds.off = headerIn.readInt();
104        protoIds.size = headerIn.readInt();
105        protoIds.off = headerIn.readInt();
106        fieldIds.size = headerIn.readInt();
107        fieldIds.off = headerIn.readInt();
108        methodIds.size = headerIn.readInt();
109        methodIds.off = headerIn.readInt();
110        classDefs.size = headerIn.readInt();
111        classDefs.off = headerIn.readInt();
112        dataSize = headerIn.readInt();
113        dataOff = headerIn.readInt();
114    }
115
116    private void readMap(Dex.Section in) throws IOException {
117        int mapSize = in.readInt();
118        Section previous = null;
119        for (int i = 0; i < mapSize; i++) {
120            short type = in.readShort();
121            in.readShort(); // unused
122            Section section = getSection(type);
123            int size = in.readInt();
124            int offset = in.readInt();
125
126            if ((section.size != 0 && section.size != size)
127                    || (section.off != -1 && section.off != offset)) {
128                throw new DexException("Unexpected map value for 0x" + Integer.toHexString(type));
129            }
130
131            section.size = size;
132            section.off = offset;
133
134            if (previous != null && previous.off > section.off) {
135                throw new DexException("Map is unsorted at " + previous + ", " + section);
136            }
137
138            previous = section;
139        }
140        Arrays.sort(sections);
141    }
142
143    public void computeSizesFromOffsets() {
144        int end = dataOff + dataSize;
145        for (int i = sections.length - 1; i >= 0; i--) {
146            Section section = sections[i];
147            if (section.off == -1) {
148                continue;
149            }
150            if (section.off > end) {
151                throw new DexException("Map is unsorted at " + section);
152            }
153            section.byteCount = end - section.off;
154            end = section.off;
155        }
156    }
157
158    private Section getSection(short type) {
159        for (Section section : sections) {
160            if (section.type == type) {
161                return section;
162            }
163        }
164        throw new IllegalArgumentException("No such map item: " + type);
165    }
166
167    public void writeHeader(Dex.Section out, int api) throws IOException {
168        out.write(DexFormat.apiToMagic(api).getBytes("UTF-8"));
169        out.writeInt(checksum);
170        out.write(signature);
171        out.writeInt(fileSize);
172        out.writeInt(SizeOf.HEADER_ITEM);
173        out.writeInt(DexFormat.ENDIAN_TAG);
174        out.writeInt(linkSize);
175        out.writeInt(linkOff);
176        out.writeInt(mapList.off);
177        out.writeInt(stringIds.size);
178        out.writeInt(stringIds.off);
179        out.writeInt(typeIds.size);
180        out.writeInt(typeIds.off);
181        out.writeInt(protoIds.size);
182        out.writeInt(protoIds.off);
183        out.writeInt(fieldIds.size);
184        out.writeInt(fieldIds.off);
185        out.writeInt(methodIds.size);
186        out.writeInt(methodIds.off);
187        out.writeInt(classDefs.size);
188        out.writeInt(classDefs.off);
189        out.writeInt(dataSize);
190        out.writeInt(dataOff);
191    }
192
193    public void writeMap(Dex.Section out) throws IOException {
194        int count = 0;
195        for (Section section : sections) {
196            if (section.exists()) {
197                count++;
198            }
199        }
200
201        out.writeInt(count);
202        for (Section section : sections) {
203            if (section.exists()) {
204                out.writeShort(section.type);
205                out.writeShort((short) 0);
206                out.writeInt(section.size);
207                out.writeInt(section.off);
208            }
209        }
210    }
211
212    public static class Section implements Comparable<Section> {
213        public final short type;
214        public int size = 0;
215        public int off = -1;
216        public int byteCount = 0;
217
218        public Section(int type) {
219            this.type = (short) type;
220        }
221
222        public boolean exists() {
223            return size > 0;
224        }
225
226        public int compareTo(Section section) {
227            if (off != section.off) {
228                return off < section.off ? -1 : 1;
229            }
230            return 0;
231        }
232
233        @Override public String toString() {
234            return String.format("Section[type=%#x,off=%#x,size=%#x]", type, off, size);
235        }
236    }
237}
238