001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.classfile; 019 020import java.io.DataInput; 021import java.io.DataOutputStream; 022import java.io.IOException; 023 024/** 025 * This class represents a (PC offset, line number) pair, i.e., a line number in 026 * the source that corresponds to a relative address in the byte code. This 027 * is used for debugging purposes. 028 * 029 * @version $Id: LineNumber.java 1806200 2017-08-25 16:33:06Z ggregory $ 030 * @see LineNumberTable 031 */ 032public final class LineNumber implements Cloneable, Node { 033 034 /** Program Counter (PC) corresponds to line */ 035 private short start_pc; 036 037 /** number in source file */ 038 private short line_number; 039 040 /** 041 * Initialize from another object. 042 * 043 * @param c the object to copy 044 */ 045 public LineNumber(final LineNumber c) { 046 this(c.getStartPC(), c.getLineNumber()); 047 } 048 049 050 /** 051 * Construct object from file stream. 052 * 053 * @param file Input stream 054 * @throws IOEXception if an I/O Exception occurs in readUnsignedShort 055 */ 056 LineNumber(final DataInput file) throws IOException { 057 this(file.readUnsignedShort(), file.readUnsignedShort()); 058 } 059 060 061 /** 062 * @param start_pc Program Counter (PC) corresponds to 063 * @param line_number line number in source file 064 */ 065 public LineNumber(final int start_pc, final int line_number) { 066 this.start_pc = (short) start_pc; 067 this.line_number = (short)line_number; 068 } 069 070 071 /** 072 * Called by objects that are traversing the nodes of the tree implicitely 073 * defined by the contents of a Java class. I.e., the hierarchy of methods, 074 * fields, attributes, etc. spawns a tree of objects. 075 * 076 * @param v Visitor object 077 */ 078 @Override 079 public void accept( final Visitor v ) { 080 v.visitLineNumber(this); 081 } 082 083 084 /** 085 * Dump line number/pc pair to file stream in binary format. 086 * 087 * @param file Output file stream 088 * @throws IOEXception if an I/O Exception occurs in writeShort 089 */ 090 public final void dump( final DataOutputStream file ) throws IOException { 091 file.writeShort(start_pc); 092 file.writeShort(line_number); 093 } 094 095 096 /** 097 * @return Corresponding source line 098 */ 099 public final int getLineNumber() { 100 return 0xffff & line_number; 101 } 102 103 104 /** 105 * @return PC in code 106 */ 107 public final int getStartPC() { 108 return 0xffff & start_pc; 109 } 110 111 112 /** 113 * @param line_number the source line number 114 */ 115 public final void setLineNumber( final int line_number ) { 116 this.line_number = (short) line_number; 117 } 118 119 120 /** 121 * @param start_pc the pc for this line number 122 */ 123 public final void setStartPC( final int start_pc ) { 124 this.start_pc = (short) start_pc; 125 } 126 127 128 /** 129 * @return String representation 130 */ 131 @Override 132 public final String toString() { 133 return "LineNumber(" + start_pc + ", " + line_number + ")"; 134 } 135 136 137 /** 138 * @return deep copy of this object 139 */ 140 public LineNumber copy() { 141 try { 142 return (LineNumber) clone(); 143 } catch (final CloneNotSupportedException e) { 144 // TODO should this throw? 145 } 146 return null; 147 } 148}