ArrayDataPseudoInstruction.java revision 3c48a886bd0175660de04f3cb77d6308742d7bad 
1/*
2 * [The "BSD licence"]
3 * Copyright (c) 2009 Ben Gruver
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.Code.Format;
30
31import org.jf.dexlib.Code.Instruction;
32import org.jf.dexlib.Code.Opcode;
33import org.jf.dexlib.Util.NumberUtils;
34import org.jf.dexlib.Util.Output;
35import org.jf.dexlib.DexFile;
36
37import java.util.Iterator;
38
39public class ArrayDataPseudoInstruction extends Instruction {
40    public static final Instruction.InstructionFactory Factory = new Factory();
41
42    @Override
43    public int getSize() {
44        int size = getElementWidth() * getElementCount();
45        return size + (size & 0x01) + 8;
46    }
47
48    public static void emit(Output out, int elementWidth, byte[] encodedValues) {
49        if (encodedValues.length % elementWidth != 0) {
50            throw new RuntimeException("There are not a whole number of " + elementWidth + " byte elements");
51        }
52
53        //write out padding, if necessary
54        if (out.getCursor() % 4 != 0) {
55            out.writeShort(0);
56        }
57
58        int elementCount = encodedValues.length / elementWidth;
59
60        out.writeByte(0x00);
61        out.writeByte(0x03);
62        out.writeShort(elementWidth);
63        out.writeInt(elementCount);
64        out.write(encodedValues);
65    }
66
67    public ArrayDataPseudoInstruction(byte[] buffer, int bufferIndex) {
68        super(Opcode.NOP, buffer, bufferIndex);
69
70        byte opcodeByte = buffer[bufferIndex++];
71        if (opcodeByte != 0x00) {
72            throw new RuntimeException("Invalid opcode byte for an ArrayData pseudo-instruction");
73        }
74
75        byte subopcodeByte = buffer[bufferIndex];
76        if (subopcodeByte != 0x03) {
77            throw new RuntimeException("Invalid sub-opcode byte for an ArrayData pseudo-instruction");
78        }
79    }
80
81    public Format getFormat() {
82        return Format.ArrayData;
83    }
84
85    public int getElementWidth() {
86        return NumberUtils.decodeUnsignedShort(buffer[bufferIndex+2], buffer[bufferIndex+3]);
87    }
88
89    public int getElementCount() {
90        return NumberUtils.decodeInt(buffer, bufferIndex+4);
91    }
92
93    public static class ArrayElement {
94        public final byte[] buffer;
95        public int bufferIndex;
96        public final int elementWidth;
97        public ArrayElement(byte[] buffer, int elementWidth) {
98            this.buffer = buffer;
99            this.elementWidth = elementWidth;
100        }
101    }
102
103    public Iterator<ArrayElement> getElements() {
104        return new Iterator<ArrayElement>() {
105            final int elementCount = getElementCount();
106            int i=0;
107            int position = bufferIndex + 8;
108            final ArrayElement arrayElement = new ArrayElement(buffer, getElementWidth());
109
110            public boolean hasNext() {
111                return i<elementCount;
112            }
113
114            public ArrayElement next() {
115                arrayElement.bufferIndex = position;
116                position += arrayElement.elementWidth;
117                i++;
118                return arrayElement;
119            }
120
121            public void remove() {
122            }
123        };
124    }
125
126    private static class Factory implements Instruction.InstructionFactory {
127        public Instruction makeInstruction(DexFile dexFile, Opcode opcode, byte[] buffer, int bufferIndex) {
128            if (opcode != Opcode.NOP) {
129                throw new RuntimeException("The opcode for an ArrayDataPseudoInstruction must by NOP");
130            }
131            return new ArrayDataPseudoInstruction(buffer, bufferIndex);
132        }
133    }
134}
135