ByteBlock.java revision f6c387128427e121477c1b32ad35cdcaa5101ba3 
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.cf.code;
18
19import com.android.dx.util.Hex;
20import com.android.dx.util.IntList;
21import com.android.dx.util.LabeledItem;
22
23/**
24 * Representation of a basic block in a bytecode array.
25 */
26public final class ByteBlock implements LabeledItem {
27    /** >= 0; label for this block */
28    private final int label;
29
30    /** >= 0; bytecode offset (inclusive) of the start of the block */
31    private final int start;
32
33    /** > start; bytecode offset (exclusive) of the end of the block */
34    private final int end;
35
36    /** non-null; list of successors that this block may branch to */
37    private final IntList successors;
38
39    /** non-null; list of exceptions caught and their handler targets */
40    private final ByteCatchList catches;
41
42    /**
43     * Constructs an instance.
44     *
45     * @param label >= 0; target label for this block
46     * @param start >= 0; bytecode offset (inclusive) of the start
47     * of the block
48     * @param end > start; bytecode offset (exclusive) of the end
49     * of the block
50     * @param successors non-null; list of successors that this block may
51     * branch to
52     * @param catches non-null; list of exceptions caught and their
53     * handler targets
54     */
55    public ByteBlock(int label, int start, int end, IntList successors,
56                     ByteCatchList catches) {
57        if (label < 0) {
58            throw new IllegalArgumentException("label < 0");
59        }
60
61        if (start < 0) {
62            throw new IllegalArgumentException("start < 0");
63        }
64
65        if (end <= start) {
66            throw new IllegalArgumentException("end <= start");
67        }
68
69        if (successors == null) {
70            throw new NullPointerException("targets == null");
71        }
72
73        int sz = successors.size();
74        for (int i = 0; i < sz; i++) {
75            if (successors.get(i) < 0) {
76                throw new IllegalArgumentException("successors[" + i +
77                                                   "] == " +
78                                                   successors.get(i));
79            }
80        }
81
82        if (catches == null) {
83            throw new NullPointerException("catches == null");
84        }
85
86        this.label = label;
87        this.start = start;
88        this.end = end;
89        this.successors = successors;
90        this.catches = catches;
91    }
92
93    /** {@inheritDoc} */
94    @Override
95    public String toString() {
96        return '{' + Hex.u2(label) + ": " + Hex.u2(start) + ".." +
97            Hex.u2(end) + '}';
98    }
99
100    /**
101     * Gets the label of this block.
102     *
103     * @return &gt;= 0; the label
104     */
105    public int getLabel() {
106        return label;
107    }
108
109    /**
110     * Gets the bytecode offset (inclusive) of the start of this block.
111     *
112     * @return &gt;= 0; the start offset
113     */
114    public int getStart() {
115        return start;
116    }
117
118    /**
119     * Gets the bytecode offset (exclusive) of the end of this block.
120     *
121     * @return &gt; getStart(); the end offset
122     */
123    public int getEnd() {
124        return end;
125    }
126
127    /**
128     * Gets the list of successors that this block may branch to
129     * non-exceptionally.
130     *
131     * @return non-null; the successor list
132     */
133    public IntList getSuccessors() {
134        return successors;
135    }
136
137    /**
138     * Gets the list of exceptions caught and their handler targets.
139     *
140     * @return non-null; the catch list
141     */
142    public ByteCatchList getCatches() {
143        return catches;
144    }
145}
146