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comparison graal/com.oracle.jvmci.bytecode/src/com/oracle/jvmci/bytecode/BytecodeSwitch.java @ 21713:454a99ca00a9

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fixed canonicalizeprojects issues
author Doug Simon <doug.simon@oracle.com>
date Wed, 03 Jun 2015 22:13:10 +0200
parents graal/com.oracle.jvmci.bytecode/src/com/oracle/graal/bytecode/BytecodeSwitch.java@1c41d00e6b2f
children
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21712:a59a0c85650a 21713:454a99ca00a9
1 /*
2 * Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package com.oracle.jvmci.bytecode;
24
25 /**
26 * An abstract class that provides the state and methods common to {@link Bytecodes#LOOKUPSWITCH}
27 * and {@link Bytecodes#TABLESWITCH} instructions.
28 */
29 public abstract class BytecodeSwitch {
30
31 /**
32 * The {@link BytecodeStream} containing the bytecode array.
33 */
34 protected final BytecodeStream stream;
35 /**
36 * Index of start of switch instruction.
37 */
38 protected final int bci;
39 /**
40 * Index of the start of the additional data for the switch instruction, aligned to a multiple
41 * of four from the method start.
42 */
43 protected final int alignedBci;
44
45 /**
46 * Constructor for a {@link BytecodeStream}.
47 *
48 * @param stream the {@code BytecodeStream} containing the switch instruction
49 * @param bci the index in the stream of the switch instruction
50 */
51 public BytecodeSwitch(BytecodeStream stream, int bci) {
52 this.stream = stream;
53 this.bci = bci;
54 this.alignedBci = (bci + 4) & 0xfffffffc;
55 }
56
57 /**
58 * Gets the current bytecode index.
59 *
60 * @return the current bytecode index
61 */
62 public int bci() {
63 return bci;
64 }
65
66 /**
67 * Gets the index of the instruction denoted by the {@code i}'th switch target.
68 *
69 * @param i index of the switch target
70 * @return the index of the instruction denoted by the {@code i}'th switch target
71 */
72 public int targetAt(int i) {
73 return bci + offsetAt(i);
74 }
75
76 /**
77 * Gets the index of the instruction for the default switch target.
78 *
79 * @return the index of the instruction for the default switch target
80 */
81 public int defaultTarget() {
82 return bci + defaultOffset();
83 }
84
85 /**
86 * Gets the offset from the start of the switch instruction to the default switch target.
87 *
88 * @return the offset to the default switch target
89 */
90 public int defaultOffset() {
91 return stream.readInt(alignedBci);
92 }
93
94 /**
95 * Gets the key at {@code i}'th switch target index.
96 *
97 * @param i the switch target index
98 * @return the key at {@code i}'th switch target index
99 */
100 public abstract int keyAt(int i);
101
102 /**
103 * Gets the offset from the start of the switch instruction for the {@code i}'th switch target.
104 *
105 * @param i the switch target index
106 * @return the offset to the {@code i}'th switch target
107 */
108 public abstract int offsetAt(int i);
109
110 /**
111 * Gets the number of switch targets.
112 *
113 * @return the number of switch targets
114 */
115 public abstract int numberOfCases();
116
117 /**
118 * Gets the total size in bytes of the switch instruction.
119 *
120 * @return the total size in bytes of the switch instruction
121 */
122 public abstract int size();
123
124 }