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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   https://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.bcel.verifier.statics;
20  
21  import java.util.Arrays;
22  
23  import org.apache.bcel.generic.Type;
24  import org.apache.bcel.verifier.exc.AssertionViolatedException;
25  import org.apache.bcel.verifier.exc.LocalVariableInfoInconsistentException;
26  
27  /**
28   * A utility class holding the information about the names and the types of the local variables in a given method.
29   */
30  public class LocalVariablesInfo {
31  
32      /** The information about the local variables is stored here. */
33      private final LocalVariableInfo[] localVariableInfos;
34  
35      /** The constructor. */
36      LocalVariablesInfo(final int maxLocals) {
37          localVariableInfos = new LocalVariableInfo[maxLocals];
38          Arrays.setAll(localVariableInfos, i -> new LocalVariableInfo());
39      }
40  
41      /**
42       * Adds information about the local variable in slot 'slot'. Automatically adds information for slot+1 if 't' is
43       * Type.LONG or Type.DOUBLE.
44       *
45       * @param slot Slot number for local variable information
46       * @param name variable name
47       * @param startPc Range in which the variable is valid.
48       * @param length length of ...
49       * @param type variable type
50       * @throws LocalVariableInfoInconsistentException if the new information conflicts with already gathered information.
51       */
52      public void add(final int slot, final String name, final int startPc, final int length, final Type type) throws LocalVariableInfoInconsistentException {
53          // The add operation on LocalVariableInfo may throw the '...Inconsistent...' exception, we don't throw it explicitly
54          // here.
55  
56          if (slot < 0 || slot >= localVariableInfos.length) {
57              throw new AssertionViolatedException("Slot number for local variable information out of range.");
58          }
59  
60          localVariableInfos[slot].add(name, startPc, length, type);
61          if (type == Type.LONG) {
62              localVariableInfos[slot + 1].add(name, startPc, length, LONG_Upper.theInstance());
63          }
64          if (type == Type.DOUBLE) {
65              localVariableInfos[slot + 1].add(name, startPc, length, DOUBLE_Upper.theInstance());
66          }
67      }
68  
69      /**
70       * Returns the LocalVariableInfo for the given slot.
71       *
72       * @param slot Slot to query.
73       * @return The LocalVariableInfo for the given slot.
74       */
75      public LocalVariableInfo getLocalVariableInfo(final int slot) {
76          if (slot < 0 || slot >= localVariableInfos.length) {
77              throw new AssertionViolatedException("Slot number for local variable information out of range.");
78          }
79          return localVariableInfos[slot];
80      }
81  }