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1
20 package edu.umd.cs.findbugs;
21
22 import java.util.ArrayList  ;
23 import java.util.List ;
24
25 import edu.umd.cs.findbugs.visitclass.DismantleBytecode;
26
27
28 public class SwitchHandler
29 {
30 private List <SwitchDetails> switchOffsetStack;
31
32 public SwitchHandler() {
33 switchOffsetStack = new ArrayList <SwitchDetails>();
34 }
35
36 public void enterSwitch( DismantleBytecode dbc ) {
37
38 SwitchDetails details = new SwitchDetails( dbc.getPC(), dbc.getSwitchOffsets(), dbc.getDefaultSwitchOffset());
39
40 int size = switchOffsetStack.size();
41 while (--size >= 0) {
42 SwitchDetails existingDetail = switchOffsetStack.get(size);
43 if (details.switchPC > (existingDetail.switchPC + existingDetail.swOffsets[existingDetail.swOffsets.length-1]))
44 switchOffsetStack.remove(size);
45 }
46 switchOffsetStack.add(details);
47 }
48
49 public boolean isOnSwitchOffset( DismantleBytecode dbc ) {
50 int pc = dbc.getPC();
51 if (pc == getDefaultOffset())
52 return false;
53
54 return (pc == getNextSwitchOffset(dbc));
55 }
56
57 public int getNextSwitchOffset( DismantleBytecode dbc ) {
58 int size = switchOffsetStack.size();
59 while (size > 0) {
60 SwitchDetails details = switchOffsetStack.get(size-1);
61
62 int nextSwitchOffset = details.getNextSwitchOffset(dbc.getPC());
63 if (nextSwitchOffset >= 0)
64 return nextSwitchOffset;
65
66 switchOffsetStack.remove(size-1);
67 size--;
68 }
69
70 return -1;
71 }
72
73 public int getDefaultOffset() {
74 int size = switchOffsetStack.size();
75 if (size == 0)
76 return -1;
77
78 SwitchDetails details = switchOffsetStack.get(size-1);
79 return details.getDefaultOffset();
80 }
81
82 public static class SwitchDetails
83 {
84 int switchPC;
85 int[] swOffsets;
86 int defaultOffset;
87 int nextOffset;
88
89 public SwitchDetails(int pc, int[] offsets, int defOffset) {
90 switchPC = pc;
91 int uniqueOffsets = 0;
92 int lastValue = -1;
93 for (int offset : offsets) {
94 if (offset != lastValue) {
95 uniqueOffsets++;
96 lastValue = offset;
97 }
98 }
99
100 swOffsets = new int[uniqueOffsets];
101 int insertPos = 0;
102 lastValue = -1;
103 for (int offset1 : offsets) {
104 if (offset1 != lastValue) {
105 swOffsets[insertPos++] = offset1;
106 lastValue = offset1;
107 }
108 }
109 defaultOffset = defOffset;
110 nextOffset = 0;
111 }
112
113 public int getNextSwitchOffset(int currentPC) {
114 while ((nextOffset < swOffsets.length) && (currentPC > (switchPC + swOffsets[nextOffset])))
115 nextOffset++;
116
117 if (nextOffset >= swOffsets.length)
118 return -1;
119
120 return switchPC + swOffsets[nextOffset];
121 }
122
123 public int getDefaultOffset() {
124 return switchPC + defaultOffset;
125 }
126 }
127 }
128 |
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