Instruction21t.java revision 4238ac2dd12461e285472dedfc0e53669b5aec35 
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.*;
32import org.jf.dexlib.DexFile;
33import org.jf.dexlib.Util.NumberUtils;
34import org.jf.dexlib.Util.AnnotatedOutput;
35
36public class Instruction21t extends Instruction implements OffsetInstruction, SingleRegisterInstruction {
37    public static final Instruction.InstructionFactory Factory = new Factory();
38    private byte regA;
39    private short offset;
40
41    public Instruction21t(Opcode opcode, short regA, short offB) {
42        super(opcode);
43
44        if (regA >= 1 << 8) {
45            throw new RuntimeException("The register number must be less than v256");
46        }
47
48        if (offB == 0) {
49            throw new RuntimeException("The offset cannot be 0.");
50        }
51
52        this.regA = (byte)regA;
53        this.offset = offB;
54    }
55
56    private Instruction21t(Opcode opcode, byte[] buffer, int bufferIndex) {
57        super(opcode);
58
59        assert buffer[bufferIndex] == opcode.value;
60
61        regA = buffer[bufferIndex + 1];
62        offset = NumberUtils.decodeShort(buffer, bufferIndex + 2);
63        assert offset != 0;
64    }
65
66    protected void writeInstruction(AnnotatedOutput out, int currentCodeOffset) {
67        out.writeByte(opcode.value);
68        out.writeByte(regA);
69        out.writeShort(offset);
70    }
71
72    public void updateOffset(int offset) {
73        if (offset < Short.MIN_VALUE || offset > Short.MAX_VALUE) {
74            throw new RuntimeException("The offset " + offset + " is out of range. It must be in [-32768, 32767]");
75        }
76        if (offset == 0) {
77            throw new RuntimeException("The offset cannot be 0");
78        }
79        this.offset = (short)offset;
80    }
81
82    public Format getFormat() {
83        return Format.Format21t;
84    }
85
86    public int getRegisterA() {
87        return regA & 0xFF;
88    }
89
90    public int getOffset() {
91        return offset;
92    }
93
94    private static class Factory implements Instruction.InstructionFactory {
95        public Instruction makeInstruction(DexFile dexFile, Opcode opcode, byte[] buffer, int bufferIndex) {
96            return new Instruction21t(opcode, buffer, bufferIndex);
97        }
98    }
99}
100