1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.dx.rop.code;
18
19import com.android.dx.util.FixedSizeList;
20
21/**
22 * List of {@link Insn} instances.
23 */
24public final class InsnList
25        extends FixedSizeList {
26    /**
27     * Constructs an instance. All indices initially contain {@code null}.
28     *
29     * @param size the size of the list
30     */
31    public InsnList(int size) {
32        super(size);
33    }
34
35    /**
36     * Gets the element at the given index. It is an error to call
37     * this with the index for an element which was never set; if you
38     * do that, this will throw {@code NullPointerException}.
39     *
40     * @param n {@code >= 0, < size();} which index
41     * @return {@code non-null;} element at that index
42     */
43    public Insn get(int n) {
44        return (Insn) get0(n);
45    }
46
47    /**
48     * Sets the instruction at the given index.
49     *
50     * @param n {@code >= 0, < size();} which index
51     * @param insn {@code non-null;} the instruction to set at {@code n}
52     */
53    public void set(int n, Insn insn) {
54        set0(n, insn);
55    }
56
57    /**
58     * Gets the last instruction. This is just a convenient shorthand for
59     * {@code get(size() - 1)}.
60     *
61     * @return {@code non-null;} the last instruction
62     */
63    public Insn getLast() {
64        return get(size() - 1);
65    }
66
67    /**
68     * Visits each instruction in the list, in order.
69     *
70     * @param visitor {@code non-null;} visitor to use
71     */
72    public void forEach(Insn.Visitor visitor) {
73        int sz = size();
74
75        for (int i = 0; i < sz; i++) {
76            get(i).accept(visitor);
77        }
78    }
79
80    /**
81     * Compares the contents of this {@code InsnList} with another.
82     * The blocks must have the same number of insns, and each Insn must
83     * also return true to {@code Insn.contentEquals()}.
84     *
85     * @param b to compare
86     * @return true in the case described above.
87     */
88    public boolean contentEquals(InsnList b) {
89        if (b == null) return false;
90
91        int sz = size();
92
93        if (sz != b.size()) return false;
94
95        for (int i = 0; i < sz; i++) {
96            if (!get(i).contentEquals(b.get(i))) {
97                return false;
98            }
99        }
100
101        return true;
102    }
103
104    /**
105     * Returns an instance that is identical to this one, except that
106     * the registers in each instruction are offset by the given
107     * amount. Mutability of the result is inherited from the
108     * original.
109     *
110     * @param delta the amount to offset register numbers by
111     * @return {@code non-null;} an appropriately-constructed instance
112     */
113    public InsnList withRegisterOffset(int delta) {
114        int sz = size();
115        InsnList result = new InsnList(sz);
116
117        for (int i = 0; i < sz; i++) {
118            Insn one = (Insn) get0(i);
119            if (one != null) {
120                result.set0(i, one.withRegisterOffset(delta));
121            }
122        }
123
124        if (isImmutable()) {
125            result.setImmutable();
126        }
127
128        return result;
129    }
130}
131