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10 package nl.tudelft.simulation.dsol.interpreter.operations;
11
12 import java.io.DataInput;
13 import java.io.IOException;
14 import java.util.HashMap;
15 import java.util.Map;
16
17 import nl.tudelft.simulation.dsol.interpreter.LocalVariable;
18 import nl.tudelft.simulation.dsol.interpreter.OperandStack;
19 import nl.tudelft.simulation.dsol.interpreter.classfile.Constant;
20
21 /***
22 * The LOOKUPSWITCH operation as defined in <a
23 * href="http://java.sun.com/docs/books/vmspec/2nd-edition/html/Instructions2.doc8.html">
24 * http://java.sun.com/docs/books/vmspec/2nd-edition/html/Instructions2.doc8.html
25 * </a>.
26 * <p>
27 * (c) copyright 2003 <a href="http://www.simulation.tudelft.nl">Delft
28 * University of Technology </a>, the Netherlands. <br>
29 * See for project information <a
30 * href="http://www.simulation.tudelft.nl">www.simulation.tudelft.nl </a> <br>
31 * License of use: <a href="http://www.gnu.org/copyleft/gpl.html">General Public
32 * License (GPL) </a>, no warranty <br>
33 *
34 * @author <a href="http://www.tbm.tudelft.nl/webstaf/peterja/index.htm">Peter
35 * Jacobs </a><a
36 * href="http://www.tbm.tudelft.nl/webstaf/alexandv/index.htm">Alexander
37 * Verbraeck </a>
38 * @version 1.3 Apr 6, 2004
39 * @since 1.4
40 */
41 public class LOOKUPSWITCH extends JumpOperation
42 {
43 /*** OP refers to the operand code */
44 public static final int OP = 171;
45
46 /*** the byteLength of this statement */
47 private int byteLength = 0;
48
49 /*** the offset table */
50 private Map offsets = new HashMap();
51
52 /***
53 * constructs a new LOOKUPSWITCH
54 *
55 * @param dataInput the dataInput
56 * @param padding the amount of bytes to pad
57 * @throws IOException on IOfailure
58 */
59 public LOOKUPSWITCH(final DataInput dataInput, final int padding)
60 throws IOException
61 {
62 super();
63
64 if (padding > 0)
65 {
66 dataInput.skipBytes(padding);
67 this.byteLength = this.byteLength + padding;
68 }
69
70 this.offsets.put("default", new Integer(dataInput.readInt()));
71 int entries = dataInput.readInt();
72 this.byteLength = this.byteLength + 8;
73 for (int i = 0; i < entries; i++)
74 {
75 Integer match = new Integer(dataInput.readInt());
76 Integer offset = new Integer(dataInput.readInt());
77 this.offsets.put(match, offset);
78 this.byteLength = this.byteLength + 8;
79 }
80 }
81
82 /***
83 * @see nl.tudelft.simulation.dsol.interpreter.operations.JumpOperation
84 * #execute(nl.tudelft.simulation.dsol.interpreter.OperandStack,
85 * nl.tudelft.simulation.dsol.interpreter.classfile.Constant[],
86 * nl.tudelft.simulation.dsol.interpreter.LocalVariable[])
87 */
88 public int execute(final OperandStack stack, final Constant[] constantPool,
89 final LocalVariable[] localVariables)
90 {
91 Integer key = (Integer) stack.pop();
92 Integer offset = (Integer) this.offsets.get(key);
93 if (offset == null)
94 {
95 offset = (Integer) this.offsets.get("default");
96 }
97 return offset.intValue();
98 }
99
100 /***
101 * @see nl.tudelft.simulation.dsol.interpreter.Operation#getByteLength()
102 */
103 public int getByteLength()
104 {
105 return OPCODE_BYTE_LENGTH + this.byteLength;
106 }
107
108 /***
109 * @see nl.tudelft.simulation.dsol.interpreter.Operation#getOpcode()
110 */
111 public int getOpcode()
112 {
113 return LOOKUPSWITCH.OP;
114 }
115 }