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Java > Open Source Codes > soot > jimple > toolkits > annotation > tags > ArrayNullCheckTag


1 /* Soot - a J*va Optimization Framework
2  * Copyright (C) 2000 Feng Qian
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with this library; if not, write to the
16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17  * Boston, MA 02111-1307, USA.
18  */

19
20 /*
21  * Modified by the Sable Research Group and others 1997-1999.
22  * See the 'credits' file distributed with Soot for the complete list of
23  * contributors. (Soot is distributed at http://www.sable.mcgill.ca/soot)
24  */

25
26 package soot.jimple.toolkits.annotation.tags;
27
28 /** ArrayNullCheckTag combines ArrayCheckTag and NullCheckTag
29  * into one tag. It uses bits of one byte value to represent
30  * the check information. The right-most two bits stand for
31  * the array bounds checks, and the right third bit represents
32  * the null check.<p>
33  *
34  * For array references, the right three bits are meaningful;
35  * for other object refrences, only null check bit should be used.
36  *
37  * @see ArrayCheckTag
38  * @see NullCheckTag
39  */

40 public class ArrayNullCheckTag implements OneByteCodeTag
41 {
42     private final static String JavaDoc NAME = "ArrayNullCheckTag";
43     
44     private byte value = 0;
45
46     public ArrayNullCheckTag()
47     {}
48
49     public ArrayNullCheckTag(byte v)
50     {
51         value = v;
52     }
53
54     public String JavaDoc getName()
55     {
56     return NAME;
57     }
58
59     public byte[] getValue()
60     {
61         byte[] bv = new byte[1];
62     bv[0] = value;
63     return bv;
64     }
65
66     public String JavaDoc toString()
67     {
68     return Byte.toString(value);
69     }
70
71   /** Accumulates another byte value by OR. */
72     public byte accumulate(byte other)
73     {
74     byte oldv = value;
75     value |= other;
76     return oldv;
77     }
78 }
79
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