1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements. See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22 package com.sun.org.apache.bcel.internal.classfile;
23
24 import java.io.DataInput;
25 import java.io.DataOutputStream;
26 import java.io.IOException;
27
28 import com.sun.org.apache.bcel.internal.Const;
29
30 /**
31 * This class represents a stack map attribute used for
32 * preverification of Java classes for the <a
33 * href="https://www.oracle.com/java/technologies/javameoverview.html">Java Platform, Micro Edition</a>
34 * (Java ME). This attribute is used by the <a
35 * href="https://www.oracle.com/technetwork/java/embedded/javame/java-mobile/kvmwp-150240.pdf">KVM</a>
36 * and contained within the Code attribute of a method. See CLDC specification
37 * 5.3.1.2
38 *
39 * @see Code
40 * @see StackMapEntry
41 * @see StackMapType
42 */
43 public final class StackMap extends Attribute {
44
45 private StackMapEntry[] map; // Table of stack map entries
46
47
48 /*
49 * @param name_index Index of name
50 * @param length Content length in bytes
51 * @param map Table of stack map entries
52 * @param constant_pool Array of constants
53 */
54 public StackMap(final int name_index, final int length, final StackMapEntry[] map, final ConstantPool constant_pool) {
55 super(Const.ATTR_STACK_MAP, name_index, length, constant_pool);
56 this.map = map;
57 }
58
59
60 /**
61 * Construct object from input stream.
62 *
63 * @param name_index Index of name
64 * @param length Content length in bytes
65 * @param input Input stream
66 * @param constant_pool Array of constants
67 * @throws IOException
68 */
69 StackMap(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) throws IOException {
70 this(name_index, length, (StackMapEntry[]) null, constant_pool);
71 final int map_length = input.readUnsignedShort();
72 map = new StackMapEntry[map_length];
73 for (int i = 0; i < map_length; i++) {
74 map[i] = new StackMapEntry(input, constant_pool);
75 }
76 }
77
78
79 /**
80 * Dump stack map table attribute to file stream in binary format.
81 *
82 * @param file Output file stream
83 * @throws IOException
84 */
85 @Override
86 public void dump( final DataOutputStream file ) throws IOException {
87 super.dump(file);
88 file.writeShort(map.length);
89 for (final StackMapEntry entry : map) {
90 entry.dump(file);
91 }
92 }
93
94
95 /**
96 * @return Array of stack map entries
97 */
98 public StackMapEntry[] getStackMap() {
99 return map;
100 }
101
102
103 /**
104 * @param map Array of stack map entries
105 */
106 public void setStackMap( final StackMapEntry[] map ) {
107 this.map = map;
108 int len = 2; // Length of 'number_of_entries' field prior to the array of stack maps
109 for (final StackMapEntry element : map) {
110 len += element.getMapEntrySize();
111 }
112 setLength(len);
113 }
114
115
116 /**
117 * @return String representation.
118 */
119 @Override
120 public String toString() {
121 final StringBuilder buf = new StringBuilder("StackMap(");
122 for (int i = 0; i < map.length; i++) {
123 buf.append(map[i]);
124 if (i < map.length - 1) {
125 buf.append(", ");
126 }
127 }
128 buf.append(')');
129 return buf.toString();
130 }
131
132
133 /**
134 * @return deep copy of this attribute
135 */
136 @Override
137 public Attribute copy( final ConstantPool _constant_pool ) {
138 final StackMap c = (StackMap) clone();
139 c.map = new StackMapEntry[map.length];
140 for (int i = 0; i < map.length; i++) {
141 c.map[i] = map[i].copy();
142 }
143 c.setConstantPool(_constant_pool);
144 return c;
145 }
146
147
148 /**
149 * Called by objects that are traversing the nodes of the tree implicitely
150 * defined by the contents of a Java class. I.e., the hierarchy of methods,
151 * fields, attributes, etc. spawns a tree of objects.
152 *
153 * @param v Visitor object
154 */
155 @Override
156 public void accept( final Visitor v ) {
157 v.visitStackMap(this);
158 }
159
160
161 public int getMapLength() {
162 return map == null ? 0 : map.length;
163 }
164 }