DexBackedPackedSwitchPayload.java revision c12bbf3a25b166c69ec47e1cf9c15ee93a9e8ef9 
1/*
2 * Copyright 2012, Google Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 *     * Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *     * Redistributions in binary form must reproduce the above
12 * copyright notice, this list of conditions and the following disclaimer
13 * in the documentation and/or other materials provided with the
14 * distribution.
15 *     * Neither the name of Google Inc. nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32package org.jf.dexlib2.dexbacked.instruction;
33
34import org.jf.dexlib2.Opcode;
35import org.jf.dexlib2.dexbacked.DexBuffer;
36import org.jf.dexlib2.dexbacked.util.FixedSizeList;
37import org.jf.dexlib2.iface.instruction.SwitchElement;
38import org.jf.dexlib2.iface.instruction.formats.PackedSwitchPayload;
39
40import javax.annotation.Nonnull;
41import java.util.List;
42
43public class DexBackedPackedSwitchPayload implements PackedSwitchPayload {
44    public static final Opcode OPCODE = Opcode.PACKED_SWITCH_PAYLOAD;
45
46    @Nonnull public final DexBuffer dexBuf;
47    private final int instructionOffset;
48
49    public final int elementCount;
50
51    private static final int ELEMENT_COUNT_OFFSET = 2;
52    private static final int FIRST_KEY_OFFSET = 4;
53    private static final int TARGETS_OFFSET = 8;
54
55    public DexBackedPackedSwitchPayload(@Nonnull DexBuffer dexBuf,
56                                        int instructionOffset) {
57        this.dexBuf = dexBuf;
58        this.instructionOffset = instructionOffset;
59
60        this.elementCount = dexBuf.readUshort(instructionOffset + ELEMENT_COUNT_OFFSET);
61    }
62
63    @Nonnull
64    @Override
65    public List<? extends SwitchElement> getSwitchElements() {
66        final int firstKey = dexBuf.readInt(instructionOffset + FIRST_KEY_OFFSET);
67        return new FixedSizeList<SwitchElement>() {
68            @Nonnull
69            @Override
70            public SwitchElement readItem(final int index) {
71                return new SwitchElement() {
72                    @Override
73                    public int getKey() {
74                        return firstKey + index;
75                    }
76
77                    @Override
78                    public int getOffset() {
79                        return dexBuf.readInt(instructionOffset + TARGETS_OFFSET + index*4);
80                    }
81                };
82            }
83
84            @Override public int size() { return elementCount; }
85        };
86    }
87
88    @Override public int getCodeUnits() { return 4 + elementCount*2; }
89    @Override public Opcode getOpcode() { return OPCODE; }
90}
91