Instruction20t.java revision 16a911620ccf7b530b873fb71cf13e8dcb88ad28 
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.Code.OffsetInstruction;
34import org.jf.dexlib.DexFile;
35import org.jf.dexlib.Util.AnnotatedOutput;
36import org.jf.dexlib.Util.NumberUtils;
37
38public class Instruction20t extends Instruction implements OffsetInstruction {
39    public static final InstructionFactory Factory = new Factory();
40    private int targetAddressOffset;
41
42    public Instruction20t(Opcode opcode, int offA) {
43        super(opcode);
44        this.targetAddressOffset = offA;
45
46        if (targetAddressOffset == 0) {
47            throw new RuntimeException("The address offset cannot be 0. Use goto/32 instead.");
48        }
49
50        //allow out of range address offsets here, so we have the option of replacing this instruction
51        //with goto/16 or goto/32 later
52    }
53
54    private Instruction20t(Opcode opcode, byte[] buffer, int bufferIndex) {
55        super(opcode);
56
57        assert buffer[bufferIndex] == opcode.value;
58
59        this.targetAddressOffset = NumberUtils.decodeShort(buffer, bufferIndex+2);
60        assert targetAddressOffset != 0;
61    }
62
63    protected void writeInstruction(AnnotatedOutput out, int currentCodeAddress) {
64        if (targetAddressOffset == 0) {
65            throw new RuntimeException("The address offset cannot be 0. Use goto/32 instead");
66        }
67
68        if (targetAddressOffset < -32768 || targetAddressOffset > 32767) {
69            throw new RuntimeException("The address offset is out of range. It must be in [-32768,-1] or [1, 32768]");
70        }
71
72        out.writeByte(opcode.value);
73        out.writeByte(0x00);
74        out.writeShort(targetAddressOffset);
75    }
76
77    public void updateTargetAddressOffset(int targetAddressOffset) {
78        this.targetAddressOffset = targetAddressOffset;
79    }
80
81    public Format getFormat() {
82        return Format.Format20t;
83    }
84
85    public int getTargetAddressOffset() {
86        return targetAddressOffset;
87    }
88
89    private static class Factory implements InstructionFactory {
90        public Instruction makeInstruction(DexFile dexFile, Opcode opcode, byte[] buffer, int bufferIndex) {
91            return new Instruction20t(opcode, buffer, bufferIndex);
92        }
93    }
94}
95