package nl.tudelft.simulation.dsol.interpreter.operations;
import java.io.DataInput;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.Map;
import nl.tudelft.simulation.dsol.interpreter.LocalVariable;
import nl.tudelft.simulation.dsol.interpreter.OperandStack;
import nl.tudelft.simulation.dsol.interpreter.classfile.Constant;
/**
* The LOOKUPSWITCH operation as defined in
* https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5 .
*
* Copyright (c) 2002-2022 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
* for project information https://simulation.tudelft.nl. The DSOL
* project is distributed under a three-clause BSD-style license, which can be found at
*
* https://simulation.tudelft.nl/dsol/3.0/license.html.
*
* @author Peter Jacobs
* @author Alexander Verbraeck
*/
public class LOOKUPSWITCH extends JumpOperation
{
/** OP refers to the operand code. */
public static final int OP = 171;
/** the byteLength of this statement. */
private int byteLength = 0;
/** the offset table. */
private Map offsets = new LinkedHashMap();
/**
* constructs a new LOOKUPSWITCH.
* @param dataInput DataInput; the dataInput
* @param padding int; the amount of bytes to pad
* @throws IOException on IOfailure
*/
public LOOKUPSWITCH(final DataInput dataInput, final int padding) throws IOException
{
super();
// If we pad, we pad!
if (padding > 0)
{
dataInput.skipBytes(padding);
this.byteLength = this.byteLength + padding;
}
this.offsets.put("default", Integer.valueOf(dataInput.readInt()));
int entries = dataInput.readInt();
this.byteLength = this.byteLength + 8;
for (int i = 0; i < entries; i++)
{
Integer match = Integer.valueOf(dataInput.readInt());
Integer offset = Integer.valueOf(dataInput.readInt());
this.offsets.put(match, offset);
this.byteLength = this.byteLength + 8;
}
}
/** {@inheritDoc} */
@Override
public int execute(final OperandStack stack, final Constant[] constantPool, final LocalVariable[] localVariables)
{
Integer key = (Integer) stack.pop();
Integer offset = this.offsets.get(key);
if (offset == null)
{
offset = this.offsets.get("default");
}
return offset.intValue();
}
/** {@inheritDoc} */
@Override
public int getByteLength()
{
return OPCODE_BYTE_LENGTH + this.byteLength;
}
/** {@inheritDoc} */
@Override
public int getOpcode()
{
return LOOKUPSWITCH.OP;
}
}