1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 /*
   6  * Licensed to the Apache Software Foundation (ASF) under one or more
   7  * contributor license agreements.  See the NOTICE file distributed with
   8  * this work for additional information regarding copyright ownership.
   9  * The ASF licenses this file to You under the Apache License, Version 2.0
  10  * (the "License"); you may not use this file except in compliance with
  11  * the License.  You may obtain a copy of the License at
  12  *
  13  *      http://www.apache.org/licenses/LICENSE-2.0
  14  *
  15  * Unless required by applicable law or agreed to in writing, software
  16  * distributed under the License is distributed on an "AS IS" BASIS,
  17  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  18  * See the License for the specific language governing permissions and
  19  * limitations under the License.
  20  */
  21 
  22 package com.sun.org.apache.bcel.internal.generic;
  23 
  24 import java.io.*;
  25 import com.sun.org.apache.bcel.internal.util.ByteSequence;
  26 
  27 /**
  28  * TABLESWITCH - Switch within given range of values, i.e., low..high
  29  *
  30  * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
  31  * @see SWITCH
  32  */
  33 public class TABLESWITCH extends Select {
  34   /**
  35    * Empty constructor needed for the Class.newInstance() statement in
  36    * Instruction.readInstruction(). Not to be used otherwise.
  37    */
  38   TABLESWITCH() {}
  39 
  40   /**
  41    * @param match sorted array of match values, match[0] must be low value,
  42    * match[match_length - 1] high value
  43    * @param targets where to branch for matched values
  44    * @param target default branch
  45    */
  46   public TABLESWITCH(int[] match, InstructionHandle[] targets,
  47                      InstructionHandle target) {
  48     super(com.sun.org.apache.bcel.internal.Constants.TABLESWITCH, match, targets, target);
  49 
  50     length = (short)(13 + match_length * 4); /* Alignment remainder assumed
  51                                               * 0 here, until dump time */
  52     fixed_length = length;
  53   }
  54 
  55   /**
  56    * Dump instruction as byte code to stream out.
  57    * @param out Output stream
  58    */
  59   public void dump(DataOutputStream out) throws IOException {
  60     super.dump(out);
  61 
  62     int low = (match_length > 0)? match[0] : 0;
  63     out.writeInt(low);
  64 
  65     int high = (match_length > 0)? match[match_length - 1] : 0;
  66     out.writeInt(high);
  67 
  68     for(int i=0; i < match_length; i++)     // jump offsets
  69       out.writeInt(indices[i] = getTargetOffset(targets[i]));
  70   }
  71 
  72   /**
  73    * Read needed data (e.g. index) from file.
  74    */
  75   protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
  76   {
  77     super.initFromFile(bytes, wide);
  78 
  79     int low    = bytes.readInt();
  80     int high   = bytes.readInt();
  81 
  82     match_length = high - low + 1;
  83     fixed_length = (short)(13 + match_length * 4);
  84     length       = (short)(fixed_length + padding);
  85 
  86     match   = new int[match_length];
  87     indices = new int[match_length];
  88     targets = new InstructionHandle[match_length];
  89 
  90     for(int i=low; i <= high; i++)
  91       match[i - low] = i;
  92 
  93     for(int i=0; i < match_length; i++) {
  94       indices[i] = bytes.readInt();
  95     }
  96   }
  97 
  98 
  99   /**
 100    * Call corresponding visitor method(s). The order is:
 101    * Call visitor methods of implemented interfaces first, then
 102    * call methods according to the class hierarchy in descending order,
 103    * i.e., the most specific visitXXX() call comes last.
 104    *
 105    * @param v Visitor object
 106    */
 107   public void accept(Visitor v) {
 108     v.visitVariableLengthInstruction(this);
 109     v.visitStackProducer(this);
 110     v.visitBranchInstruction(this);
 111     v.visitSelect(this);
 112     v.visitTABLESWITCH(this);
 113   }
 114 }