Item


1   /***
2    * ASM: a very small and fast Java bytecode manipulation framework
3    * Copyright (c) 2000,2002,2003 INRIA, France Telecom 
4    * All rights reserved.
5    *
6    * Redistribution and use in source and binary forms, with or without
7    * modification, are permitted provided that the following conditions
8    * are met:
9    * 1. Redistributions of source code must retain the above copyright
10   *    notice, this list of conditions and the following disclaimer.
11   * 2. Redistributions in binary form must reproduce the above copyright
12   *    notice, this list of conditions and the following disclaimer in the
13   *    documentation and/or other materials provided with the distribution.
14   * 3. Neither the name of the copyright holders nor the names of its
15   *    contributors may be used to endorse or promote products derived from
16   *    this software without specific prior written permission.
17   *
18   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
28   * THE POSSIBILITY OF SUCH DAMAGE.
29   */
30  
31  package oracle.toplink.libraries.asm;
32  
33  /**
34   * A constant pool item. Constant pool items can be created with the 'newXXX'
35   * methods in the {@link ClassWriter} class.
36   * 
37   * @author Eric Bruneton
38   */
39  
40  final class Item {
41  
42    /**
43     * Index of this item in the constant pool.
44     */
45  
46    short index;
47  
48    /**
49     * Type of this constant pool item. A single class is used to represent all
50     * constant pool item types, in order to minimize the bytecode size of this
51     * package. The value of this field is one of the constants defined in the
52     * {@link ClassWriter ClassWriter} class.
53     */
54  
55    int type;
56  
57    /**
58     * Value of this item, for a {@link ClassWriter#INT INT} item.
59     */
60  
61    int intVal;
62  
63    /**
64     * Value of this item, for a {@link ClassWriter#LONG LONG} item.
65     */
66  
67    long longVal;
68  
69    /**
70     * Value of this item, for a {@link ClassWriter#FLOAT FLOAT} item.
71     */
72  
73    float floatVal;
74  
75    /**
76     * Value of this item, for a {@link ClassWriter#DOUBLE DOUBLE} item.
77     */
78  
79    double doubleVal;
80  
81    /**
82     * First part of the value of this item, for items that do not hold a
83     * primitive value.
84     */
85  
86    String   strVal1;
87  
88    /**
89     * Second part of the value of this item, for items that do not hold a
90     * primitive value.
91     */
92  
93    String   strVal2;
94  
95    /**
96     * Third part of the value of this item, for items that do not hold a
97     * primitive value.
98     */
99  
100   String   strVal3;
101 
102   /**
103    * The hash code value of this constant pool item.
104    */
105 
106   int hashCode;
107 
108   /**
109    * Link to another constant pool item, used for collision lists in the
110    * constant pool's hash table.
111    */
112 
113   Item next;
114 
115   /**
116    * Constructs an uninitialized {@link Item Item} object.
117    */
118 
119   Item () {
120   }
121 
122   /**
123    * Constructs a copy of the given item.
124    *
125    * @param index index of the item to be constructed.
126    * @param i the item that must be copied into the item to be constructed.
127    */
128 
129   Item (final short index, final Item i) {
130     this.index = index;
131     type = i.type;
132     intVal = i.intVal;
133     longVal = i.longVal;
134     floatVal = i.floatVal;
135     doubleVal = i.doubleVal;
136     strVal1 = i.strVal1;
137     strVal2 = i.strVal2;
138     strVal3 = i.strVal3;
139     hashCode = i.hashCode;
140   }
141 
142   /**
143    * Sets this item to an {@link ClassWriter#INT INT} item.
144    *
145    * @param intVal the value of this item.
146    */
147 
148   void set (final int intVal) {
149     this.type = ClassWriter.INT;
150     this.intVal = intVal;
151     this.hashCode = 0x7FFFFFFF & (type + intVal);
152   }
153 
154   /**
155    * Sets this item to a {@link ClassWriter#LONG LONG} item.
156    *
157    * @param longVal the value of this item.
158    */
159 
160   void set (final long longVal) {
161     this.type = ClassWriter.LONG;
162     this.longVal = longVal;
163     this.hashCode = 0x7FFFFFFF & (type + (int)longVal);
164   }
165 
166   /**
167    * Sets this item to a {@link ClassWriter#FLOAT FLOAT} item.
168    *
169    * @param floatVal the value of this item.
170    */
171 
172   void set (final float floatVal) {
173     this.type = ClassWriter.FLOAT;
174     this.floatVal = floatVal;
175     this.hashCode = 0x7FFFFFFF & (type + (int)floatVal);
176   }
177 
178   /**
179    * Sets this item to a {@link ClassWriter#DOUBLE DOUBLE} item.
180    *
181    * @param doubleVal the value of this item.
182    */
183 
184   void set (final double doubleVal) {
185     this.type = ClassWriter.DOUBLE;
186     this.doubleVal = doubleVal;
187     this.hashCode = 0x7FFFFFFF & (type + (int)doubleVal);
188   }
189 
190   /**
191    * Sets this item to an item that do not hold a primitive value.
192    *
193    * @param type the type of this item.
194    * @param strVal1 first part of the value of this item.
195    * @param strVal2 second part of the value of this item.
196    * @param strVal3 third part of the value of this item.
197    */
198 
199   void set (
200     final int type,
201     final String   strVal1,
202     final String   strVal2,
203     final String   strVal3)
204   {
205     this.type = type;
206     this.strVal1 = strVal1;
207     this.strVal2 = strVal2;
208     this.strVal3 = strVal3;
209     switch (type) {
210       case ClassWriter.UTF8:
211       case ClassWriter.STR:
212       case ClassWriter.CLASS:
213         hashCode = 0x7FFFFFFF & (type + strVal1.hashCode());
214         return;
215       case ClassWriter.NAME_TYPE:
216         hashCode = 0x7FFFFFFF & (type + strVal1.hashCode()*strVal2.hashCode());
217         return;
218       //case ClassWriter.FIELD:
219       //case ClassWriter.METH:
220       //case ClassWriter.IMETH:
221       default:
222         hashCode = 0x7FFFFFFF & (type +
223           strVal1.hashCode()*strVal2.hashCode()*strVal3.hashCode());
224     }
225   }
226 
227   /**
228    * Indicates if the given item is equal to this one.
229    *
230    * @param i the item to be compared to this one.
231    * @return <tt>true</tt> if the given item if equal to this one,
232    *      <tt>false</tt> otherwise.
233    */
234 
235   boolean isEqualTo (final Item i) {
236     if (i.type == type) {
237       switch (type) {
238         case ClassWriter.INT:
239           return i.intVal == intVal;
240         case ClassWriter.LONG:
241           return i.longVal == longVal;
242         case ClassWriter.FLOAT:
243           return i.floatVal == floatVal;
244         case ClassWriter.DOUBLE:
245           return i.doubleVal == doubleVal;
246         case ClassWriter.UTF8:
247         case ClassWriter.STR:
248         case ClassWriter.CLASS:
249           return i.strVal1.equals(strVal1);
250         case ClassWriter.NAME_TYPE:
251           return i.strVal1.equals(strVal1) &&
252                  i.strVal2.equals(strVal2);
253         //case ClassWriter.FIELD:
254         //case ClassWriter.METH:
255         //case ClassWriter.IMETH:
256         default:
257           return i.strVal1.equals(strVal1) &&
258                  i.strVal2.equals(strVal2) &&
259                  i.strVal3.equals(strVal3);
260       }
261     }
262     return false;
263   }
264 }
265
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