TABLESWITCH.java revision 628:2bfaf29cc90b 
1/*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5package com.sun.org.apache.bcel.internal.generic;
6
7/* ====================================================================
8 * The Apache Software License, Version 1.1
9 *
10 * Copyright (c) 2001 The Apache Software Foundation.  All rights
11 * reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
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17 * 1. Redistributions of source code must retain the above copyright
18 *    notice, this list of conditions and the following disclaimer.
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20 * 2. Redistributions in binary form must reproduce the above copyright
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29 *    Alternately, this acknowledgment may appear in the software itself,
30 *    if and wherever such third-party acknowledgments normally appear.
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54 *
55 * This software consists of voluntary contributions made by many
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59 */
60import java.io.*;
61import com.sun.org.apache.bcel.internal.util.ByteSequence;
62
63/**
64 * TABLESWITCH - Switch within given range of values, i.e., low..high
65 *
66 * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
67 * @see SWITCH
68 */
69public class TABLESWITCH extends Select {
70  /**
71   * Empty constructor needed for the Class.newInstance() statement in
72   * Instruction.readInstruction(). Not to be used otherwise.
73   */
74  TABLESWITCH() {}
75
76  /**
77   * @param match sorted array of match values, match[0] must be low value,
78   * match[match_length - 1] high value
79   * @param targets where to branch for matched values
80   * @param target default branch
81   */
82  public TABLESWITCH(int[] match, InstructionHandle[] targets,
83                     InstructionHandle target) {
84    super(com.sun.org.apache.bcel.internal.Constants.TABLESWITCH, match, targets, target);
85
86    length = (short)(13 + match_length * 4); /* Alignment remainder assumed
87                                              * 0 here, until dump time */
88    fixed_length = length;
89  }
90
91  /**
92   * Dump instruction as byte code to stream out.
93   * @param out Output stream
94   */
95  public void dump(DataOutputStream out) throws IOException {
96    super.dump(out);
97
98    int low = (match_length > 0)? match[0] : 0;
99    out.writeInt(low);
100
101    int high = (match_length > 0)? match[match_length - 1] : 0;
102    out.writeInt(high);
103
104    for(int i=0; i < match_length; i++)     // jump offsets
105      out.writeInt(indices[i] = getTargetOffset(targets[i]));
106  }
107
108  /**
109   * Read needed data (e.g. index) from file.
110   */
111  protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
112  {
113    super.initFromFile(bytes, wide);
114
115    int low    = bytes.readInt();
116    int high   = bytes.readInt();
117
118    match_length = high - low + 1;
119    fixed_length = (short)(13 + match_length * 4);
120    length       = (short)(fixed_length + padding);
121
122    match   = new int[match_length];
123    indices = new int[match_length];
124    targets = new InstructionHandle[match_length];
125
126    for(int i=low; i <= high; i++)
127      match[i - low] = i;
128
129    for(int i=0; i < match_length; i++) {
130      indices[i] = bytes.readInt();
131    }
132  }
133
134
135  /**
136   * Call corresponding visitor method(s). The order is:
137   * Call visitor methods of implemented interfaces first, then
138   * call methods according to the class hierarchy in descending order,
139   * i.e., the most specific visitXXX() call comes last.
140   *
141   * @param v Visitor object
142   */
143  public void accept(Visitor v) {
144    v.visitVariableLengthInstruction(this);
145    v.visitStackProducer(this);
146    v.visitBranchInstruction(this);
147    v.visitSelect(this);
148    v.visitTABLESWITCH(this);
149  }
150}
151