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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:
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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
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25   * 3. The end-user documentation included with the redistribution,
26   *    if any, must include the following acknowledgment:
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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
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55   * This software consists of voluntary contributions made by many
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58   * <http://www.apache.org/>.
59   */
60  import com.sun.org.apache.bcel.internal.Constants;
61  import java.io.*;
62  
63  /**
64   * Wrapper class for push operations, which are implemented either as BIPUSH,
65   * LDC or xCONST_n instructions.
66   *
67   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
68   */
69  public final class PUSH
70    implements CompoundInstruction, VariableLengthInstruction, InstructionConstants
71  {
72    private Instruction instruction;
73  
74    /**
75     * This constructor also applies for values of type short, char, byte
76     *
77     * @param cp Constant pool
78     * @param value to be pushed
79     */
80    public PUSH(ConstantPoolGen cp, int value) {
81      if((value >= -1) && (value <= 5)) // Use ICONST_n
82        instruction = INSTRUCTIONS[Constants.ICONST_0 + value];
83      else if((value >= -128) && (value <= 127)) // Use BIPUSH
84        instruction = new BIPUSH((byte)value);
85      else if((value >= -32768) && (value <= 32767)) // Use SIPUSH
86        instruction = new SIPUSH((short)value);
87      else // If everything fails create a Constant pool entry
88        instruction = new LDC(cp.addInteger(value));
89    }
90  
91    /**
92     * @param cp Constant pool
93     * @param value to be pushed
94     */
95    public PUSH(ConstantPoolGen cp, boolean value) {
96      instruction = INSTRUCTIONS[Constants.ICONST_0 + (value? 1 : 0)];
97    }
98  
99    /**
100    * @param cp Constant pool
101    * @param value to be pushed
102    */
103   public PUSH(ConstantPoolGen cp, float value) {
104     if(value == 0.0)
105       instruction = FCONST_0;
106     else if(value == 1.0)
107       instruction = FCONST_1;
108     else if(value == 2.0)
109       instruction = FCONST_2;
110     else // Create a Constant pool entry
111       instruction = new LDC(cp.addFloat(value));
112   }
113 
114   /**
115    * @param cp Constant pool
116    * @param value to be pushed
117    */
118   public PUSH(ConstantPoolGen cp, long value) {
119     if(value == 0)
120       instruction = LCONST_0;
121     else if(value == 1)
122       instruction = LCONST_1;
123     else // Create a Constant pool entry
124       instruction = new LDC2_W(cp.addLong(value));
125   }
126 
127   /**
128    * @param cp Constant pool
129    * @param value to be pushed
130    */
131   public PUSH(ConstantPoolGen cp, double value) {
132     if(value == 0.0)
133       instruction = DCONST_0;
134     else if(value == 1.0)
135       instruction = DCONST_1;
136     else // Create a Constant pool entry
137       instruction = new LDC2_W(cp.addDouble(value));
138   }
139 
140   /**
141    * @param cp Constant pool
142    * @param value to be pushed
143    */
144   public PUSH(ConstantPoolGen cp, String value) {
145     if(value == null)
146       instruction = ACONST_NULL;
147     else // Create a Constant pool entry
148       instruction = new LDC(cp.addString(value));
149   }
150 
151   /**
152    * @param cp Constant pool
153    * @param value to be pushed
154    */
155   public PUSH(ConstantPoolGen cp, Number value) {
156     if((value instanceof Integer) || (value instanceof Short) || (value instanceof Byte))
157       instruction = new PUSH(cp, value.intValue()).instruction;
158     else if(value instanceof Double)
159       instruction = new PUSH(cp, value.doubleValue()).instruction;
160     else if(value instanceof Float)
161       instruction = new PUSH(cp, value.floatValue()).instruction;
162     else if(value instanceof Long)
163       instruction = new PUSH(cp, value.longValue()).instruction;
164     else
165       throw new ClassGenException("What's this: " + value);
166   }
167 
168   /**
169    * @param cp Constant pool
170    * @param value to be pushed
171    */
172   public PUSH(ConstantPoolGen cp, Character value) {
173     this(cp, (int)value.charValue());
174   }
175 
176   /**
177    * @param cp Constant pool
178    * @param value to be pushed
179    */
180   public PUSH(ConstantPoolGen cp, Boolean value) {
181     this(cp, value.booleanValue());
182   }
183 
184   public final InstructionList getInstructionList() {
185     return new InstructionList(instruction);
186   }
187 
188   public final Instruction getInstruction() {
189     return instruction;
190   }
191 
192   /**
193    * @return mnemonic for instruction
194    */
195   public String toString() {
196     return instruction.toString() + " (PUSH)";
197   }
198 }