SparseSwitchMethodItem.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.baksmali.Adaptors.Format;

import org.jf.baksmali.Adaptors.LabelMethodItem;
import org.jf.baksmali.Adaptors.MethodDefinition;
import org.jf.util.IndentingWriter;
import org.jf.baksmali.Renderers.IntegerRenderer;
import org.jf.dexlib.Code.Format.SparseSwitchDataPseudoInstruction;
import org.jf.dexlib.CodeItem;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class SparseSwitchMethodItem extends InstructionMethodItem<SparseSwitchDataPseudoInstruction> {
    private final List<SparseSwitchTarget> targets;

    public SparseSwitchMethodItem(MethodDefinition methodDefinition, CodeItem codeItem, int codeAddress,
                                  SparseSwitchDataPseudoInstruction instruction) {
        super(codeItem, codeAddress, instruction);

        int baseCodeAddress = methodDefinition.getSparseSwitchBaseAddress(codeAddress);

        targets = new ArrayList<SparseSwitchTarget>();
        Iterator<SparseSwitchDataPseudoInstruction.SparseSwitchTarget> iterator = instruction.iterateKeysAndTargets();
        if (baseCodeAddress >= 0) {
            while (iterator.hasNext()) {
                SparseSwitchDataPseudoInstruction.SparseSwitchTarget target = iterator.next();
                SparseSwitchLabelTarget sparseSwitchLabelTarget = new SparseSwitchLabelTarget();
                sparseSwitchLabelTarget.Key = target.key;

                LabelMethodItem label = new LabelMethodItem(baseCodeAddress + target.targetAddressOffset, "sswitch_");
                label = methodDefinition.getLabelCache().internLabel(label);
                sparseSwitchLabelTarget.Target = label;

                targets.add(sparseSwitchLabelTarget);
            }
        } else {
            //if we couldn't determine a base address, just use relative offsets rather than labels
            while (iterator.hasNext()) {
                SparseSwitchDataPseudoInstruction.SparseSwitchTarget target = iterator.next();
                SparseSwitchOffsetTarget sparseSwitchOffsetTarget = new SparseSwitchOffsetTarget();
                sparseSwitchOffsetTarget.Key = target.key;

                sparseSwitchOffsetTarget.Target = target.targetAddressOffset;
                targets.add(sparseSwitchOffsetTarget);
            }
        }
    }

    @Override
    public boolean writeTo(IndentingWriter writer) throws IOException {
        writer.write(".sparse-switch\n");
        writer.indent(4);
        for (SparseSwitchTarget target: targets) {
            IntegerRenderer.writeTo(writer, target.Key);
            writer.write(" -> ");
            target.writeTargetTo(writer);
            writer.write('\n');
        }
        writer.deindent(4);
        writer.write(".end sparse-switch");
        return true;
    }

    private static abstract class SparseSwitchTarget {
        public int Key;
        public abstract void writeTargetTo(IndentingWriter writer) throws IOException;
    }

    private static class SparseSwitchLabelTarget extends SparseSwitchTarget {
        public LabelMethodItem Target;
        public void writeTargetTo(IndentingWriter writer) throws IOException {
            Target.writeTo(writer);
        }
    }

    private static class SparseSwitchOffsetTarget extends SparseSwitchTarget {
        public int Target;
        public void writeTargetTo(IndentingWriter writer) throws IOException {
            if (Target >= 0) {
                writer.write('+');
            }
            writer.printSignedIntAsDec(Target);
        }
    }
}