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Java > Open Source Codes > jbet > BranchTarget


1 /*
2  * JBET - Java Binary Enhancement Tool
3  * Copyright (c) 2003 Networks Associates Technology, Inc.
4  *
5  * This software was developed under DARPA/SPAWAR contract
6  * N66001-00-C-8602 "SPMA" as part of the
7  * DARPA OASIS research program.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  * notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in the
16  * documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * 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 AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30
31 package jbet;
32 import java.io.*;
33 import java.util.*;
34
35 /**
36  * Store a mapping between a literal instruction offset (used for
37  * branching instructions) and a pointer to the Instruction object
38  * that the offset points to. As transformations are performed on
39  * code, the literal offsets may become invalid. This object exists
40  * to support regeneration of correct offsets from the Instruction
41  * objects.
42  *
43  * @author Lee Badger
44  * @version 0.1
45  * @since JDK 1.1.8
46  */
47
48 public class BranchTarget implements Cloneable JavaDoc {
49     public int key;
50     public int offset;
51     public Instruction instr;
52     public Block block;
53     public String JavaDoc label;
54
55     /** Constructor.
56      */
57     public BranchTarget() {
58     key = 0;
59     offset = 0;
60     instr = null;
61     block = null;
62     }
63
64     public BranchTarget(Instruction ins) {
65     key = 0;
66     offset = 0;
67     instr = ins;
68     block = null;
69     }
70
71     /** Duplicate this instance.
72      * @return a clone
73      */
74     public BranchTarget dup() {
75     try {
76         return (BranchTarget) clone();
77     } catch (Exception JavaDoc e) {
78         return null;
79     }
80     }
81
82     public BranchTarget (BranchTarget in) {
83     key = in.key;
84     offset = in.offset;
85     instr = in.instr;
86     block = in.block;
87     label = in.label;
88     }
89
90     /** Return a printable string, either a block, or a PC value.
91      * @return a printable string.
92      */
93     public String JavaDoc recString() {
94     if (block != null)
95         return "#B" + block.swval;
96     else if (instr != null)
97         return Integer.toString (instr.pc());
98     else
99         return "BAD";
100     }
101 }
102
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