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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one or more
3    *  contributor license agreements.  See the NOTICE file distributed with
4    *  this work for additional information regarding copyright ownership.
5    *  The ASF licenses this file to You under the Apache License, Version 2.0
6    *  (the "License"); you may not use this file except in compliance with
7    *  the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  package org.apache.commons.compress.harmony.unpack200.bytecode.forms;
18  
19  import java.util.Objects;
20  
21  import org.apache.commons.compress.harmony.pack200.Pack200Exception;
22  import org.apache.commons.compress.harmony.unpack200.SegmentConstantPool;
23  import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
24  import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
25  import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
26  
27  /**
28   * Abstract class of all ByteCodeForms which add a nested entry from the globalConstantPool.
29   */
30  public abstract class ReferenceForm extends ByteCodeForm {
31  
32      public ReferenceForm(final int opcode, final String name, final int[] rewrite) {
33          super(opcode, name, rewrite);
34      }
35  
36      protected abstract int getOffset(OperandManager operandManager);
37  
38      protected abstract int getPoolID();
39  
40      /*
41       * (non-Javadoc)
42       *
43       * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons.
44       * compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable,
45       * org.apache.commons.compress.harmony.unpack200.Segment)
46       */
47      @Override
48      public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, final int codeLength) {
49          final int offset = getOffset(operandManager);
50          try {
51              setNestedEntries(byteCode, operandManager, offset);
52          } catch (final Pack200Exception ex) {
53              throw new Error("Got a pack200 exception. What to do?");
54          }
55      }
56  
57      protected void setNestedEntries(final ByteCode byteCode, final OperandManager operandManager, final int offset) throws Pack200Exception {
58          final SegmentConstantPool globalPool = operandManager.globalConstantPool();
59          final ClassFileEntry[] nested = { globalPool.getConstantPoolEntry(getPoolID(), offset) };
60          Objects.requireNonNull(nested[0], "Null nested entries are not allowed");
61          byteCode.setNested(nested);
62          byteCode.setNestedPositions(new int[][] { { 0, 2 } });
63      }
64  }