1/*
2 * [The "BSD licence"]
3 * Copyright (c) 2010 Ben Gruver (JesusFreke)
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29package org.jf.dexlib.Code;
30
31import org.jf.dexlib.*;
32import org.jf.dexlib.Util.NumberUtils;
33
34public abstract class InstructionWithReference extends Instruction {
35    private Item referencedItem;
36    private ReferenceType referenceType;
37
38    protected InstructionWithReference(Opcode opcode, Item referencedItem) {
39        super(opcode);
40        this.referencedItem = referencedItem;
41        this.referenceType = opcode.referenceType;
42        checkReferenceType();
43    }
44
45    protected InstructionWithReference(Opcode opcode, Item referencedItem, ReferenceType referenceType) {
46        super(opcode);
47        this.referencedItem = referencedItem;
48        this.referenceType = referenceType;
49        checkReferenceType();
50    }
51
52    protected InstructionWithReference(DexFile dexFile, Opcode opcode, byte[] buffer, int bufferIndex) {
53        super(opcode);
54
55        this.referenceType = readReferenceType(opcode, buffer, bufferIndex);
56        int itemIndex = getReferencedItemIndex(buffer, bufferIndex);
57        lookupReferencedItem(dexFile, opcode, itemIndex);
58    }
59
60    protected int getReferencedItemIndex(byte[] buffer, int bufferIndex) {
61        return NumberUtils.decodeUnsignedShort(buffer, bufferIndex + 2);
62    }
63
64    public ReferenceType getReferenceType() {
65        return referenceType;
66    }
67
68    public Item getReferencedItem() {
69        return referencedItem;
70    }
71
72    protected ReferenceType readReferenceType(Opcode opcode, byte[] buffer, int bufferIndex) {
73        return opcode.referenceType;
74    }
75
76    private void lookupReferencedItem(DexFile dexFile, Opcode opcode, int itemIndex) {
77        switch (referenceType) {
78            case field:
79                referencedItem = dexFile.FieldIdsSection.getItemByIndex(itemIndex);
80                return;
81            case method:
82                referencedItem = dexFile.MethodIdsSection.getItemByIndex(itemIndex);
83                return;
84            case type:
85                referencedItem = dexFile.TypeIdsSection.getItemByIndex(itemIndex);
86                return;
87            case string:
88                referencedItem = dexFile.StringIdsSection.getItemByIndex(itemIndex);
89        }
90    }
91
92
93    private void checkReferenceType() {
94        switch (referenceType) {
95            case field:
96                if (!(referencedItem instanceof FieldIdItem)) {
97                    throw new RuntimeException(referencedItem.getClass().getSimpleName() +
98                            " is the wrong item type for opcode " + opcode.name + ". Expecting FieldIdItem.");
99                }
100                return;
101            case method:
102                if (!(referencedItem instanceof MethodIdItem)) {
103                    throw new RuntimeException(referencedItem.getClass().getSimpleName() +
104                            " is the wrong item type for opcode " + opcode.name + ". Expecting MethodIdItem.");
105                }
106                return;
107            case type:
108                if (!(referencedItem instanceof TypeIdItem)) {
109                    throw new RuntimeException(referencedItem.getClass().getSimpleName() +
110                            " is the wrong item type for opcode " + opcode.name + ". Expecting TypeIdItem.");
111                }
112                return;
113            case string:
114                if (!(referencedItem instanceof StringIdItem)) {
115                    throw new RuntimeException(referencedItem.getClass().getSimpleName() +
116                            " is the wrong item type for opcode " + opcode.name + ". Expecting StringIdItem.");
117                }
118                return;
119            default:
120                if (referencedItem != null) {
121                    throw new RuntimeException(referencedItem.getClass().getSimpleName() +
122                            " is invalid for opcode " + opcode.name + ". This opcode does not reference an item");
123                }
124        }
125    }
126}
127