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1   /*
2    * reserved comment block
3    * DO NOT REMOVE OR ALTER!
4    */
5   package 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:
16   *
17   * 1. Redistributions of source code must retain the above copyright
18   *    notice, this list of conditions and the following disclaimer.
19   *
20   * 2. Redistributions in binary form must reproduce the above copyright
21   *    notice, this list of conditions and the following disclaimer in
22   *    the documentation and/or other materials provided with the
23   *    distribution.
24   *
25   * 3. The end-user documentation included with the redistribution,
26   *    if any, must include the following acknowledgment:
27   *       "This product includes software developed by the
28   *        Apache Software Foundation (http://www.apache.org/)."
29   *    Alternately, this acknowledgment may appear in the software itself,
30   *    if and wherever such third-party acknowledgments normally appear.
31   *
32   * 4. The names "Apache" and "Apache Software Foundation" and
33   *    "Apache BCEL" must not be used to endorse or promote products
34   *    derived from this software without prior written permission. For
35   *    written permission, please contact apache@apache.org.
36   *
37   * 5. Products derived from this software may not be called "Apache",
38   *    "Apache BCEL", nor may "Apache" appear in their name, without
39   *    prior written permission of the Apache Software Foundation.
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41   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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47   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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49   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52   * SUCH DAMAGE.
53   * ====================================================================
54   *
55   * This software consists of voluntary contributions made by many
56   * individuals on behalf of the Apache Software Foundation.  For more
57   * information on the Apache Software Foundation, please see
58   * <http://www.apache.org/>.
59   */
60  
61  import java.io.*;
62  import com.sun.org.apache.bcel.internal.util.ByteSequence;
63  import com.sun.org.apache.bcel.internal.Constants;
64  import com.sun.org.apache.bcel.internal.classfile.*;
65  
66  /**
67   * Abstract super class for instructions that use an index into the
68   * constant pool such as LDC, INVOKEVIRTUAL, etc.
69   *
70   * @see ConstantPoolGen
71   * @see LDC
72   * @see INVOKEVIRTUAL
73   *
74   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
75   */
76  public abstract class CPInstruction extends Instruction
77    implements TypedInstruction, IndexedInstruction
78  {
79    protected int index; // index to constant pool
80  
81    /**
82     * Empty constructor needed for the Class.newInstance() statement in
83     * Instruction.readInstruction(). Not to be used otherwise.
84     */
85    CPInstruction() {}
86  
87    /**
88     * @param index to constant pool
89     */
90    protected CPInstruction(short opcode, int index) {
91      super(opcode, (short)3);
92      setIndex(index);
93    }
94  
95    /**
96     * Dump instruction as byte code to stream out.
97     * @param out Output stream
98     */
99    public void dump(DataOutputStream out) throws IOException {
100     out.writeByte(opcode);
101     out.writeShort(index);
102   }
103 
104   /**
105    * Long output format:
106    *
107    * &lt;name of opcode&gt; "["&lt;opcode number&gt;"]"
108    * "("&lt;length of instruction&gt;")" "&lt;"&lt; constant pool index&gt;"&gt;"
109    *
110    * @param verbose long/short format switch
111    * @return mnemonic for instruction
112    */
113   public String toString(boolean verbose) {
114     return super.toString(verbose) + " " + index;
115   }
116 
117   /**
118    * @return mnemonic for instruction with symbolic references resolved
119    */
120   public String toString(ConstantPool cp) {
121     Constant c   = cp.getConstant(index);
122     String   str = cp.constantToString(c);
123 
124     if(c instanceof ConstantClass)
125       str = str.replace('.', '/');
126 
127     return com.sun.org.apache.bcel.internal.Constants.OPCODE_NAMES[opcode] + " " + str;
128   }
129 
130   /**
131    * Read needed data (i.e., index) from file.
132    * @param bytes input stream
133    * @param wide wide prefix?
134    */
135   protected void initFromFile(ByteSequence bytes, boolean wide)
136        throws IOException
137   {
138     setIndex(bytes.readUnsignedShort());
139     length = 3;
140   }
141 
142   /**
143    * @return index in constant pool referred by this instruction.
144    */
145   public final int getIndex() { return index; }
146 
147   /**
148    * Set the index to constant pool.
149    * @param index in  constant pool.
150    */
151   public void setIndex(int index) {
152     if(index < 0)
153       throw new ClassGenException("Negative index value: " + index);
154 
155     this.index = index;
156   }
157 
158   /** @return type related with this instruction.
159    */
160   public Type getType(ConstantPoolGen cpg) {
161     ConstantPool cp   = cpg.getConstantPool();
162     String       name = cp.getConstantString(index, com.sun.org.apache.bcel.internal.Constants.CONSTANT_Class);
163 
164     if(!name.startsWith("["))
165       name = "L" + name + ";";
166 
167     return Type.getType(name);
168   }
169 }