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      1 /*
      2  * [The "BSD licence"]
      3  * Copyright (c) 2010 Ben Gruver (JesusFreke)
      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 
     29 package org.jf.dexlib.Code.Format;
     30 
     31 import org.jf.dexlib.Code.Instruction;
     32 import org.jf.dexlib.Code.OffsetInstruction;
     33 import org.jf.dexlib.Code.Opcode;
     34 import org.jf.dexlib.Code.SingleRegisterInstruction;
     35 import org.jf.dexlib.DexFile;
     36 import org.jf.dexlib.Util.AnnotatedOutput;
     37 import org.jf.dexlib.Util.NumberUtils;
     38 
     39 public class Instruction21t extends OffsetInstruction implements SingleRegisterInstruction {
     40     public static final Instruction.InstructionFactory Factory = new Factory();
     41     private byte regA;
     42     private short targetAddressOffset;
     43 
     44     public Instruction21t(Opcode opcode, short regA, short offB) {
     45         super(opcode);
     46 
     47         if (regA >= 1 << 8) {
     48             throw new RuntimeException("The register number must be less than v256");
     49         }
     50 
     51         if (offB == 0) {
     52             throw new RuntimeException("The address offset cannot be 0.");
     53         }
     54 
     55         this.regA = (byte)regA;
     56         this.targetAddressOffset = offB;
     57     }
     58 
     59     private Instruction21t(Opcode opcode, byte[] buffer, int bufferIndex) {
     60         super(opcode);
     61 
     62         assert buffer[bufferIndex] == opcode.value;
     63 
     64         regA = buffer[bufferIndex + 1];
     65         targetAddressOffset = NumberUtils.decodeShort(buffer, bufferIndex + 2);
     66         assert targetAddressOffset != 0;
     67     }
     68 
     69     protected void writeInstruction(AnnotatedOutput out, int currentCodeAddress) {
     70         out.writeByte(opcode.value);
     71         out.writeByte(regA);
     72         out.writeShort(targetAddressOffset);
     73     }
     74 
     75     public void updateTargetAddressOffset(int targetAddressOffset) {
     76         if (targetAddressOffset < Short.MIN_VALUE || targetAddressOffset > Short.MAX_VALUE) {
     77             throw new RuntimeException("The address offset " + targetAddressOffset +
     78                     " is out of range. It must be in [-32768, 32767]");
     79         }
     80         if (targetAddressOffset == 0) {
     81             throw new RuntimeException("The address offset cannot be 0");
     82         }
     83         this.targetAddressOffset = (short) targetAddressOffset;
     84     }
     85 
     86     public Format getFormat() {
     87         return Format.Format21t;
     88     }
     89 
     90     public int getRegisterA() {
     91         return regA & 0xFF;
     92     }
     93 
     94     public int getTargetAddressOffset() {
     95         return targetAddressOffset;
     96     }
     97 
     98     private static class Factory implements Instruction.InstructionFactory {
     99         public Instruction makeInstruction(DexFile dexFile, Opcode opcode, byte[] buffer, int bufferIndex) {
    100             return new Instruction21t(opcode, buffer, bufferIndex);
    101         }
    102     }
    103 }
    104