/* Copyright (C) 2004-2007 Sami Koivu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package net.sf.rej.java.instruction;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import net.sf.rej.util.ByteArrayByteParser;
import net.sf.rej.util.ByteParser;
import net.sf.rej.util.ByteSerializer;
/**
* Access jump table by index and jump.
*
* @author Sami Koivu
*/
public class _tableswitch extends Instruction {
public static final int OPCODE = 0xaa;
public static final String MNEMONIC = "tableswitch";
private Label def;
private int low;
private int high;
private Map<Integer, Label> offsets;
public _tableswitch() {
// empty constructor
}
@Override
public int getOpcode() {
return OPCODE;
}
@Override
public String getMnemonic() {
return MNEMONIC;
}
@Override
public int getSize() {
throw new RuntimeException(
"Variant sized, getSize() must not be called, use getSize(DecompilationContext) instead.");
}
@Override
public int getSize(DecompilationContext dc) {
if (this.offsets == null) {
ByteParser parser = dc.getParser();
int startPos = parser.getPosition();
parser.getByte(); // jump one byte forward -- this is the opcode
// byte
int pad = 0;
while ((dc.getPosition() + pad + 1) % 4 != 0) {
parser.getByte();
pad++;
}
parser.getInt(); // def
int low = (int) parser.getInt(); // low
int high = (int) parser.getInt(); // high
for (int i = low; i <= high; i++) {
parser.getInt(); // jump offset
}
return parser.getPosition() - startPos;
} else {
int size = 1; // opcode
while ((dc.getPosition() + size) % 4 != 0) {
size++;
}
size += 12; // def, low, high
size += ((this.high - this.low) + 1) * 4; // number of offsets
// times
// 4 bytes
return size;
}
}
@Override
public void setData(byte[] data, DecompilationContext dc) {
ByteParser parser = new ByteArrayByteParser(data);
parser.setBigEndian(true);
parser.getByte(); // throw away OPCODE
while ((dc.getPosition() + parser.getPosition()) % 4 != 0) {
parser.getByte(); // throw away bytes until we are in a position
// divisible by 4
}
this.def = new Label((int) parser.getInt() + dc.getPosition(),
"table_label_def");
this.low = (int) parser.getInt();
this.high = (int) parser.getInt();
this.offsets = new HashMap<Integer, Label>();
for (int i = this.low; i <= this.high; i++) {
Label label = new Label((int) parser.getInt() + dc.getPosition(),
"table_label_" + i);
if (label.getPosition() != this.def.getPosition()) {
this.offsets.put(Integer.valueOf(i), label);
}
}
}
@Override
public byte[] getData(DecompilationContext dc) {
ByteSerializer ser = new ByteSerializer(true);
ser.addByte(OPCODE);
while ((ser.size() + dc.getPosition()) % 4 != 0) {
ser.addByte(0);
}
ser.addInt(this.def.getPosition() - dc.getPosition());
ser.addInt(this.low);
ser.addInt(this.high);
for (int i = this.low; i <= this.high; i++) {
Label l = this.offsets.get(i);
if (l != null) {
ser.addInt(l.getPosition() - dc.getPosition());
} else {
ser.addInt(this.def.getPosition() - dc.getPosition());
}
}
return ser.getBytes();
}
@Override
public void execute(ExecutionContext ec) {
}
@Override
public List<Label> getLabels() {
List<Label> al = new ArrayList<Label>();
al.add(this.def);
al.addAll(this.offsets.values());
return al;
}
@Override
public Parameters getParameters() {
Parameters params = getParameterTypes();
params.addValue(this.def);
params.addValue(this.offsets);
return params;
}
@Override
public Parameters getParameterTypes() {
return new Parameters(new ParameterType[] { ParameterType.TYPE_LABEL,
ParameterType.TYPE_SWITCH });
}
@Override
@SuppressWarnings("unchecked")
public void setParameters(Parameters params) {
this.def = (Label) params.getObject(0);
this.offsets = (Map) params.getObject(1);
}
@Override
public List<StackElement> getPoppedElements(DecompilationContext dc) {
List<StackElement> elements = new ArrayList<StackElement>();
elements.add(new StackElement("index", StackElementType.INT));
return elements;
}
}