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
25 import com.sun.org.apache.bcel.internal.Constants;
26 import java.io.*;
27
28 /**
29 * This class represents a table of line numbers for debugging
30 * purposes. This attribute is used by the <em>Code</em> attribute. It
31 * contains pairs of PCs and line numbers.
32 *
33 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
34 * @see Code
35 * @see LineNumber
36 */
37 public final class LineNumberTable extends Attribute {
38 private int line_number_table_length;
39 private LineNumber[] line_number_table; // Table of line/numbers pairs
40
41 /*
42 * Initialize from another object. Note that both objects use the same
43 * references (shallow copy). Use copy() for a physical copy.
44 */
45 public LineNumberTable(LineNumberTable c) {
46 this(c.getNameIndex(), c.getLength(), c.getLineNumberTable(),
47 c.getConstantPool());
48 }
49
50 /*
51 * @param name_index Index of name
52 * @param length Content length in bytes
53 * @param line_number_table Table of line/numbers pairs
54 * @param constant_pool Array of constants
55 */
56 public LineNumberTable(int name_index, int length,
57 LineNumber[] line_number_table,
58 ConstantPool constant_pool)
59 {
60 super(Constants.ATTR_LINE_NUMBER_TABLE, name_index, length, constant_pool);
61 setLineNumberTable(line_number_table);
62 }
63
64 /**
65 * Construct object from file stream.
66 * @param name_index Index of name
67 * @param length Content length in bytes
68 * @param file Input stream
69 * @throws IOException
70 * @param constant_pool Array of constants
71 */
72 LineNumberTable(int name_index, int length, DataInputStream file,
73 ConstantPool constant_pool) throws IOException
74 {
75 this(name_index, length, (LineNumber[])null, constant_pool);
76 line_number_table_length = (file.readUnsignedShort());
77 line_number_table = new LineNumber[line_number_table_length];
78
79 for(int i=0; i < line_number_table_length; i++)
80 line_number_table[i] = new LineNumber(file);
81 }
82 /**
83 * Called by objects that are traversing the nodes of the tree implicitely
84 * defined by the contents of a Java class. I.e., the hierarchy of methods,
85 * fields, attributes, etc. spawns a tree of objects.
86 *
87 * @param v Visitor object
88 */
89 public void accept(Visitor v) {
90 v.visitLineNumberTable(this);
91 }
92 /**
93 * Dump line number table attribute to file stream in binary format.
94 *
95 * @param file Output file stream
96 * @throws IOException
97 */
98 public final void dump(DataOutputStream file) throws IOException
99 {
100 super.dump(file);
101 file.writeShort(line_number_table_length);
102 for(int i=0; i < line_number_table_length; i++)
103 line_number_table[i].dump(file);
104 }
105
106 /**
107 * @return Array of (pc offset, line number) pairs.
108 */
109 public final LineNumber[] getLineNumberTable() { return line_number_table; }
110
111 /**
112 * @param line_number_table.
113 */
114 public final void setLineNumberTable(LineNumber[] line_number_table) {
115 this.line_number_table = line_number_table;
116
117 line_number_table_length = (line_number_table == null)? 0 :
118 line_number_table.length;
119 }
120
121 /**
122 * @return String representation.
123 */
124 public final String toString() {
125 StringBuffer buf = new StringBuffer();
126 StringBuffer line = new StringBuffer();
127
128 for(int i=0; i < line_number_table_length; i++) {
129 line.append(line_number_table[i].toString());
130
131 if(i < line_number_table_length - 1)
132 line.append(", ");
133
134 if(line.length() > 72) {
135 line.append('\n');
136 buf.append(line);
137 line.setLength(0);
138 }
139 }
140
141 buf.append(line);
142
143 return buf.toString();
144 }
145
146 /**
147 * Map byte code positions to source code lines.
148 *
149 * @param pos byte code offset
150 * @return corresponding line in source code
151 */
152 public int getSourceLine(int pos) {
153 int l = 0, r = line_number_table_length-1;
154
155 if(r < 0) // array is empty
156 return -1;
157
158 int min_index = -1, min=-1;
159
160 /* Do a binary search since the array is ordered.
161 */
162 do {
163 int i = (l + r) / 2;
164 int j = line_number_table[i].getStartPC();
165
166 if(j == pos)
167 return line_number_table[i].getLineNumber();
168 else if(pos < j) // else constrain search area
169 r = i - 1;
170 else // pos > j
171 l = i + 1;
172
173 /* If exact match can't be found (which is the most common case)
174 * return the line number that corresponds to the greatest index less
175 * than pos.
176 */
177 if(j < pos && j > min) {
178 min = j;
179 min_index = i;
180 }
181 } while(l <= r);
182
183 /* It's possible that we did not find any valid entry for the bytecode
184 * offset we were looking for.
185 */
186 if (min_index < 0)
187 return -1;
188
189 return line_number_table[min_index].getLineNumber();
190 }
191
192 /**
193 * @return deep copy of this attribute
194 */
195 public Attribute copy(ConstantPool constant_pool) {
196 LineNumberTable c = (LineNumberTable)clone();
197
198 c.line_number_table = new LineNumber[line_number_table_length];
199 for(int i=0; i < line_number_table_length; i++)
200 c.line_number_table[i] = line_number_table[i].copy();
201
202 c.constant_pool = constant_pool;
203 return c;
204 }
205
206 public final int getTableLength() { return line_number_table_length; }
207 }