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Java > Open Source Codes > com > sun > org > apache > bcel > internal > generic > TABLESWITCH


1 package com.sun.org.apache.bcel.internal.generic;
2
3 /* ====================================================================
4  * The Apache Software License, Version 1.1
5  *
6  * Copyright (c) 2001 The Apache Software Foundation. All rights
7  * reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
20  *
21  * 3. The end-user documentation included with the redistribution,
22  * if any, must include the following acknowledgment:
23  * "This product includes software developed by the
24  * Apache Software Foundation (http://www.apache.org/)."
25  * Alternately, this acknowledgment may appear in the software itself,
26  * if and wherever such third-party acknowledgments normally appear.
27  *
28  * 4. The names "Apache" and "Apache Software Foundation" and
29  * "Apache BCEL" must not be used to endorse or promote products
30  * derived from this software without prior written permission. For
31  * written permission, please contact apache@apache.org.
32  *
33  * 5. Products derived from this software may not be called "Apache",
34  * "Apache BCEL", nor may "Apache" appear in their name, without
35  * prior written permission of the Apache Software Foundation.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals on behalf of the Apache Software Foundation. For more
53  * information on the Apache Software Foundation, please see
54  * <http://www.apache.org/>.
55  */
56 import java.io.*;
57 import com.sun.org.apache.bcel.internal.util.ByteSequence;
58
59 /**
60  * TABLESWITCH - Switch within given range of values, i.e., low..high
61  *
62  * @version $Id: TABLESWITCH.java,v 1.1.1.1 2001/10/29 20:00:27 jvanzyl Exp $
63  * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
64  * @see SWITCH
65  */
66 public class TABLESWITCH extends Select {
67   /**
68    * Empty constructor needed for the Class.newInstance() statement in
69    * Instruction.readInstruction(). Not to be used otherwise.
70    */
71   TABLESWITCH() {}
72
73   /**
74    * @param match sorted array of match values, match[0] must be low value,
75    * match[match_length - 1] high value
76    * @param targets where to branch for matched values
77    * @param target default branch
78    */
79   public TABLESWITCH(int[] match, InstructionHandle[] targets,
80              InstructionHandle target) {
81     super(com.sun.org.apache.bcel.internal.Constants.TABLESWITCH, match, targets, target);
82     
83     length = (short)(13 + match_length * 4); /* Alignment remainder assumed
84                           * 0 here, until dump time */
85     fixed_length = length;
86   }
87
88   /**
89    * Dump instruction as byte code to stream out.
90    * @param out Output stream
91    */
92   public void dump(DataOutputStream out) throws IOException {
93     super.dump(out);
94
95     int low = (match_length > 0)? match[0] : 0;
96     out.writeInt(low);
97
98     int high = (match_length > 0)? match[match_length - 1] : 0;
99     out.writeInt(high);
100
101     for(int i=0; i < match_length; i++) // jump offsets
102 out.writeInt(indices[i] = getTargetOffset(targets[i]));
103   }
104
105   /**
106    * Read needed data (e.g. index) from file.
107    */
108   protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
109   {
110     super.initFromFile(bytes, wide);
111
112     int low = bytes.readInt();
113     int high = bytes.readInt();
114
115     match_length = high - low + 1;
116     fixed_length = (short)(13 + match_length * 4);
117     length = (short)(fixed_length + padding);
118
119     match = new int[match_length];
120     indices = new int[match_length];
121     targets = new InstructionHandle[match_length];
122
123     for(int i=low; i <= high; i++)
124       match[i - low] = i;
125
126     for(int i=0; i < match_length; i++) {
127       indices[i] = bytes.readInt();
128     }
129   }
130
131
132   /**
133    * Call corresponding visitor method(s). The order is:
134    * Call visitor methods of implemented interfaces first, then
135    * call methods according to the class hierarchy in descending order,
136    * i.e., the most specific visitXXX() call comes last.
137    *
138    * @param v Visitor object
139    */
140   public void accept(Visitor v) {
141     v.visitVariableLengthInstruction(this);
142     v.visitStackProducer(this);
143     v.visitBranchInstruction(this);
144     v.visitSelect(this);
145     v.visitTABLESWITCH(this);
146   }
147 }
148
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