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1   /*
2    * Copyright  2000-2004 The Apache Software Foundation
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License"); 
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License. 
15   *
16   */
17  package org.apache.bcel.generic;
18  
19  import java.io.DataOutputStream;
20  import java.io.IOException;
21  import org.apache.bcel.util.ByteSequence;
22  
23  /*** 
24   * TABLESWITCH - Switch within given range of values, i.e., low..high
25   *
26   * @version $Id: TABLESWITCH.java 386056 2006-03-15 11:31:56Z tcurdt $
27   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
28   * @see SWITCH
29   */
30  public class TABLESWITCH extends Select {
31  
32      /***
33       * Empty constructor needed for the Class.newInstance() statement in
34       * Instruction.readInstruction(). Not to be used otherwise.
35       */
36      TABLESWITCH() {
37      }
38  
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 defaultTarget default branch
45       */
46      public TABLESWITCH(int[] match, InstructionHandle[] targets, InstructionHandle defaultTarget) {
47          super(org.apache.bcel.Constants.TABLESWITCH, match, targets, defaultTarget);
48          length = (short) (13 + match_length * 4); /* Alignment remainder assumed
49           * 0 here, until dump time */
50          fixed_length = length;
51      }
52  
53  
54      /***
55       * Dump instruction as byte code to stream out.
56       * @param out Output stream
57       */
58      public void dump( DataOutputStream out ) throws IOException {
59          super.dump(out);
60          int low = (match_length > 0) ? match[0] : 0;
61          out.writeInt(low);
62          int high = (match_length > 0) ? match[match_length - 1] : 0;
63          out.writeInt(high);
64          for (int i = 0; i < match_length; i++) {
65              out.writeInt(indices[i] = getTargetOffset(targets[i]));
66          }
67      }
68  
69  
70      /***
71       * Read needed data (e.g. index) from file.
72       */
73      protected void initFromFile( ByteSequence bytes, boolean wide ) throws IOException {
74          super.initFromFile(bytes, wide);
75          int low = bytes.readInt();
76          int high = bytes.readInt();
77          match_length = high - low + 1;
78          fixed_length = (short) (13 + match_length * 4);
79          length = (short) (fixed_length + padding);
80          match = new int[match_length];
81          indices = new int[match_length];
82          targets = new InstructionHandle[match_length];
83          for (int i = low; i <= high; i++) {
84              match[i - low] = i;
85          }
86          for (int i = 0; i < match_length; i++) {
87              indices[i] = bytes.readInt();
88          }
89      }
90  
91  
92      /***
93       * Call corresponding visitor method(s). The order is:
94       * Call visitor methods of implemented interfaces first, then
95       * call methods according to the class hierarchy in descending order,
96       * i.e., the most specific visitXXX() call comes last.
97       *
98       * @param v Visitor object
99       */
100     public void accept( Visitor v ) {
101         v.visitVariableLengthInstruction(this);
102         v.visitStackProducer(this);
103         v.visitBranchInstruction(this);
104         v.visitSelect(this);
105         v.visitTABLESWITCH(this);
106     }
107 }