package nl.tudelft.simulation.dsol.interpreter.operations; import java.io.DataInput; import java.io.IOException; import java.util.ArrayList; import java.util.List; import nl.tudelft.simulation.dsol.interpreter.LocalVariable; import nl.tudelft.simulation.dsol.interpreter.OperandStack; import nl.tudelft.simulation.dsol.interpreter.classfile.Constant; /** * The TABLESWITCH operation as defined in * http://java.sun.com/docs/books/vmspec/2nd-edition/html/Instructions2.doc14.html . *

* (c) copyright 2002-2014 Delft University of Technology.
* BSD-style license. See DSOL License.
* @author Peter Jacobs * @author Alexander Verbraeck */ public class TABLESWITCH extends JumpOperation { /** OP refers to the operand code. */ public static final int OP = 170; /** the byteLength of this statement. */ private int byteLength = 0; /** the start position of the table. */ private int lowValue = -1; /** the end position of the table. */ private int highValue = -1; /** the offset table. */ private List offsets = new ArrayList(); /** * constructs a new TABLESWITCH. * @param dataInput the dataInput * @param padding the number of bytes to pad * @throws IOException on IOfailure */ public TABLESWITCH(final DataInput dataInput, final int padding) throws IOException { super(); // First we pad if (padding > 0) { dataInput.skipBytes(padding); this.byteLength = this.byteLength + padding; } // Now we place the default value at position 0 this.offsets.add(Integer.valueOf(dataInput.readInt())); this.lowValue = dataInput.readInt(); this.highValue = dataInput.readInt(); int entries = this.highValue - this.lowValue + 1; this.byteLength = this.byteLength + 12; for (int i = 0; i < entries; i++) { Integer offset = Integer.valueOf(dataInput.readInt()); this.offsets.add(offset); this.byteLength = this.byteLength + 4; } } /** {@inheritDoc} */ @Override public final int execute(final OperandStack stack, final Constant[] constantPool, final LocalVariable[] localVariables) { int index = ((Integer) stack.pop()).intValue(); int offset = -1; if (index < this.lowValue || index > this.highValue) { offset = this.offsets.get(0).intValue(); } else { offset = this.offsets.get(index - this.lowValue + 1).intValue(); } return offset; } /** {@inheritDoc} */ @Override public final int getByteLength() { return OPCODE_BYTE_LENGTH + this.byteLength; } /** {@inheritDoc} */ @Override public final int getOpcode() { return TABLESWITCH.OP; } }