1/* 2 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package com.sun.tools.classfile; 27 28import java.io.IOException; 29import java.util.Iterator; 30import java.util.NoSuchElementException; 31 32/** 33 * See JVMS, section 4.8.3. 34 * 35 * <p><b>This is NOT part of any supported API. 36 * If you write code that depends on this, you do so at your own risk. 37 * This code and its internal interfaces are subject to change or 38 * deletion without notice.</b> 39 */ 40public class Code_attribute extends Attribute { 41 public static class InvalidIndex extends AttributeException { 42 private static final long serialVersionUID = -8904527774589382802L; 43 InvalidIndex(int index) { 44 this.index = index; 45 } 46 47 @Override 48 public String getMessage() { 49 // i18n 50 return "invalid index " + index + " in Code attribute"; 51 } 52 53 public final int index; 54 } 55 56 Code_attribute(ClassReader cr, int name_index, int length) 57 throws IOException, ConstantPoolException { 58 super(name_index, length); 59 max_stack = cr.readUnsignedShort(); 60 max_locals = cr.readUnsignedShort(); 61 code_length = cr.readInt(); 62 code = new byte[code_length]; 63 cr.readFully(code); 64 exception_table_length = cr.readUnsignedShort(); 65 exception_table = new Exception_data[exception_table_length]; 66 for (int i = 0; i < exception_table_length; i++) 67 exception_table[i] = new Exception_data(cr); 68 attributes = new Attributes(cr); 69 } 70 71 public int getByte(int offset) throws InvalidIndex { 72 if (offset < 0 || offset >= code.length) 73 throw new InvalidIndex(offset); 74 return code[offset]; 75 } 76 77 public int getUnsignedByte(int offset) throws InvalidIndex { 78 if (offset < 0 || offset >= code.length) 79 throw new InvalidIndex(offset); 80 return code[offset] & 0xff; 81 } 82 83 public int getShort(int offset) throws InvalidIndex { 84 if (offset < 0 || offset + 1 >= code.length) 85 throw new InvalidIndex(offset); 86 return (code[offset] << 8) | (code[offset + 1] & 0xFF); 87 } 88 89 public int getUnsignedShort(int offset) throws InvalidIndex { 90 if (offset < 0 || offset + 1 >= code.length) 91 throw new InvalidIndex(offset); 92 return ((code[offset] << 8) | (code[offset + 1] & 0xFF)) & 0xFFFF; 93 } 94 95 public int getInt(int offset) throws InvalidIndex { 96 if (offset < 0 || offset + 3 >= code.length) 97 throw new InvalidIndex(offset); 98 return (getShort(offset) << 16) | (getShort(offset + 2) & 0xFFFF); 99 } 100 101 public <R, D> R accept(Visitor<R, D> visitor, D data) { 102 return visitor.visitCode(this, data); 103 } 104 105 public Iterable<Instruction> getInstructions() { 106 return () -> new Iterator<Instruction>() { 107 108 public boolean hasNext() { 109 return (next != null); 110 } 111 112 public Instruction next() { 113 if (next == null) 114 throw new NoSuchElementException(); 115 116 current = next; 117 pc += current.length(); 118 next = (pc < code.length ? new Instruction(code, pc) : null); 119 return current; 120 } 121 122 public void remove() { 123 throw new UnsupportedOperationException("Not supported."); 124 } 125 126 Instruction current = null; 127 int pc = 0; 128 Instruction next = new Instruction(code, pc); 129 130 }; 131 } 132 133 public final int max_stack; 134 public final int max_locals; 135 public final int code_length; 136 public final byte[] code; 137 public final int exception_table_length; 138 public final Exception_data[] exception_table; 139 public final Attributes attributes; 140 141 public static class Exception_data { 142 Exception_data(ClassReader cr) throws IOException { 143 start_pc = cr.readUnsignedShort(); 144 end_pc = cr.readUnsignedShort(); 145 handler_pc = cr.readUnsignedShort(); 146 catch_type = cr.readUnsignedShort(); 147 } 148 149 public final int start_pc; 150 public final int end_pc; 151 public final int handler_pc; 152 public final int catch_type; 153 } 154} 155