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.DexBackedDexFile;
36import org.jf.dexlib2.dexbacked.util.FixedSizeList;
37import org.jf.dexlib2.iface.instruction.formats.ArrayPayload;
38import org.jf.util.ExceptionWithContext;
39
40import javax.annotation.Nonnull;
41import java.util.List;
42
43public class DexBackedArrayPayload extends DexBackedInstruction implements ArrayPayload {
44    public static final Opcode OPCODE = Opcode.ARRAY_PAYLOAD;
45
46    public final int elementWidth;
47    public final int elementCount;
48
49    private static final int ELEMENT_WIDTH_OFFSET = 2;
50    private static final int ELEMENT_COUNT_OFFSET = 4;
51    private static final int ELEMENTS_OFFSET = 8;
52
53    public DexBackedArrayPayload(@Nonnull DexBackedDexFile dexFile,
54                                 int instructionStart) {
55        super(dexFile, OPCODE, instructionStart);
56
57        elementWidth = dexFile.readUshort(instructionStart + ELEMENT_WIDTH_OFFSET);
58        elementCount = dexFile.readSmallUint(instructionStart + ELEMENT_COUNT_OFFSET);
59        if (((long)elementWidth) * elementCount > Integer.MAX_VALUE) {
60            throw new ExceptionWithContext("Invalid array-payload instruction: element width*count overflows");
61        }
62    }
63
64    @Override public int getElementWidth() { return elementWidth; }
65
66    @Nonnull
67    @Override
68    public List<Number> getArrayElements() {
69        final int elementsStart = instructionStart + ELEMENTS_OFFSET;
70
71        abstract class ReturnedList extends FixedSizeList<Number> {
72            @Override public int size() { return elementCount; }
73        }
74
75        switch (elementWidth) {
76            case 1:
77                return new ReturnedList() {
78                    @Nonnull
79                    @Override
80                    public Number readItem(int index) {
81                        return dexFile.readByte(elementsStart + index);
82                    }
83                };
84            case 2:
85                return new ReturnedList() {
86                    @Nonnull
87                    @Override
88                    public Number readItem(int index) {
89                        return dexFile.readShort(elementsStart + index*2);
90                    }
91                };
92            case 4:
93                return new ReturnedList() {
94                    @Nonnull
95                    @Override
96                    public Number readItem(int index) {
97                        return dexFile.readInt(elementsStart + index*4);
98                    }
99                };
100            case 8:
101                return new ReturnedList() {
102                    @Nonnull
103                    @Override
104                    public Number readItem(int index) {
105                        return dexFile.readLong(elementsStart + index*8);
106                    }
107                };
108            default:
109                throw new ExceptionWithContext("Invalid element width: %d", elementWidth);
110        }
111    }
112
113    @Override
114    public int getCodeUnits() {
115        return 4 + (elementWidth*elementCount + 1) / 2;
116    }
117}
118