InstructionIterator.java

/*
 * [The "BSD licence"]
 * Copyright (c) 2010 Ben Gruver (JesusFreke)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.jf.dexlib.Code;

import org.jf.dexlib.Code.Format.*;
import org.jf.dexlib.DexFile;
import org.jf.dexlib.Util.ExceptionWithContext;
import org.jf.dexlib.Util.Hex;

public class InstructionIterator {
    public static void IterateInstructions(DexFile dexFile, byte[] insns, ProcessInstructionDelegate delegate) {
        int insnsPosition = 0;

        while (insnsPosition < insns.length) {
            try
            {
                short opcodeValue = (short)(insns[insnsPosition] & 0xFF);
                if (opcodeValue == 0xFF) {
                    opcodeValue = (short)((0xFF << 8) | insns[insnsPosition+1]);
                }

                Opcode opcode = Opcode.getOpcodeByValue(opcodeValue);

                Instruction instruction = null;

                if (opcode == null) {
                    System.err.println(String.format("unknown opcode encountered - %x. Treating as nop.",
                            (opcodeValue & 0xFFFF)));
                    instruction = new UnknownInstruction(opcodeValue);
                } else {
                    if (opcode == Opcode.NOP) {
                        byte secondByte = insns[insnsPosition + 1];
                        switch (secondByte) {
                            case 0:
                            {
                                instruction = new Instruction10x(Opcode.NOP, insns, insnsPosition);
                                break;
                            }
                            case 1:
                            {
                                instruction = new PackedSwitchDataPseudoInstruction(insns, insnsPosition);
                                break;
                            }
                            case 2:
                            {
                                instruction = new SparseSwitchDataPseudoInstruction(insns, insnsPosition);
                                break;
                            }
                            case 3:
                            {
                                instruction = new ArrayDataPseudoInstruction(insns, insnsPosition);
                                break;
                            }
                        }
                    } else {
                        instruction = opcode.format.Factory.makeInstruction(dexFile, opcode, insns, insnsPosition);
                    }
                }

                assert instruction != null;

                delegate.ProcessInstruction(insnsPosition/2, instruction);
                insnsPosition += instruction.getSize(insnsPosition/2)*2;
            } catch (Exception ex) {
                throw ExceptionWithContext.withContext(ex, "Error occured at code address " + insnsPosition * 2);
            }
        }
    }

    public static interface ProcessInstructionDelegate {
        public void ProcessInstruction(int codeAddress, Instruction instruction);
    }
}