001 /*
002 * Copyright 2007-2008 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package com.sun.tools.classfile;
027
028 import java.io.IOException;
029
030 /**
031 * See JVMS3, section 4.8.3.
032 *
033 * <p><b>This is NOT part of any API supported by Sun Microsystems. If
034 * you write code that depends on this, you do so at your own risk.
035 * This code and its internal interfaces are subject to change or
036 * deletion without notice.</b>
037 */
038 public class Code_attribute extends Attribute {
039 public class InvalidIndex extends AttributeException {
040 private static final long serialVersionUID = -8904527774589382802L;
041 InvalidIndex(int index) {
042 this.index = index;
043 }
044
045 @Override
046 public String getMessage() {
047 // i18n
048 return "invalid index " + index + " in Code attribute";
049 }
050
051 public final int index;
052 }
053
054 Code_attribute(ClassReader cr, int name_index, int length)
055 throws IOException, ConstantPoolException {
056 super(name_index, length);
057 max_stack = cr.readUnsignedShort();
058 max_locals = cr.readUnsignedShort();
059 code_length = cr.readInt();
060 code = new byte[code_length];
061 cr.readFully(code);
062 exception_table_langth = cr.readUnsignedShort();
063 exception_table = new Exception_data[exception_table_langth];
064 for (int i = 0; i < exception_table_langth; i++)
065 exception_table[i] = new Exception_data(cr);
066 attributes = new Attributes(cr);
067 }
068
069 public int getByte(int offset) throws InvalidIndex {
070 if (offset < 0 || offset >= code.length)
071 throw new InvalidIndex(offset);
072 return code[offset];
073 }
074
075 public int getUnsignedByte(int offset) throws InvalidIndex {
076 if (offset < 0 || offset >= code.length)
077 throw new InvalidIndex(offset);
078 return code[offset] & 0xff;
079 }
080
081 public int getShort(int offset) throws InvalidIndex {
082 if (offset < 0 || offset + 1 >= code.length)
083 throw new InvalidIndex(offset);
084 return (code[offset] << 8) | (code[offset + 1] & 0xFF);
085 }
086
087 public int getUnsignedShort(int offset) throws InvalidIndex {
088 if (offset < 0 || offset + 1 >= code.length)
089 throw new InvalidIndex(offset);
090 return ((code[offset] << 8) | (code[offset + 1] & 0xFF)) & 0xFFFF;
091 }
092
093 public int getInt(int offset) throws InvalidIndex {
094 if (offset < 0 || offset + 3 >= code.length)
095 throw new InvalidIndex(offset);
096 return (getShort(offset) << 16) | (getShort(offset + 2) & 0xFFFF);
097 }
098
099 public <R, D> R accept(Visitor<R, D> visitor, D data) {
100 return visitor.visitCode(this, data);
101 }
102
103 public final int max_stack;
104 public final int max_locals;
105 public final int code_length;
106 public final byte[] code;
107 public final int exception_table_langth;
108 public final Exception_data[] exception_table;
109 public final Attributes attributes;
110
111 public class Exception_data {
112 Exception_data(ClassReader cr) throws IOException {
113 start_pc = cr.readUnsignedShort();
114 end_pc = cr.readUnsignedShort();
115 handler_pc = cr.readUnsignedShort();
116 catch_type = cr.readUnsignedShort();
117 }
118
119 public final int start_pc;
120 public final int end_pc;
121 public final int handler_pc;
122 public final int catch_type;
123 }
124 }