1 /* 2 * Copyright (c) 2007, 2008, 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 26 package com.sun.tools.classfile; 27 28 import java.io.BufferedInputStream; 29 import java.io.ByteArrayInputStream; 30 import java.io.DataInputStream; 31 import java.io.IOException; 32 import java.io.InputStream; 33 import java.util.Objects; 34 35 /** 36 * <p><b>This is NOT part of any supported API. 37 * If you write code that depends on this, you do so at your own risk. 38 * This code and its internal interfaces are subject to change or 39 * deletion without notice.</b> 40 */ 41 public class ClassReader { 42 ClassReader(ClassFile classFile, InputStream in, Attribute.Factory attributeFactory) throws IOException { 43 this.classFile = Objects.requireNonNull(classFile); 44 this.attributeFactory = Objects.requireNonNull(attributeFactory); 45 this.in = new DataInputStream(new BufferedInputStream(in)); 46 } 47 48 ClassFile getClassFile() { 49 return classFile; 50 } 51 52 ConstantPool getConstantPool() { 53 return classFile.constant_pool; 54 } 55 56 public Attribute readAttribute() throws IOException { 57 int name_index = readUnsignedShort(); 58 int length = readInt(); 59 byte[] data = new byte[length]; 60 readFully(data); 61 62 DataInputStream prev = in; 63 in = new DataInputStream(new ByteArrayInputStream(data)); 64 try { 65 return attributeFactory.createAttribute(this, name_index, data); 66 } finally { 67 in = prev; 68 } 69 } 70 71 public void readFully(byte[] b) throws IOException { 72 in.readFully(b); 73 } 74 75 public int readUnsignedByte() throws IOException { 76 return in.readUnsignedByte(); 77 } 78 79 public int readUnsignedShort() throws IOException { 80 return in.readUnsignedShort(); 81 } 82 83 public int readInt() throws IOException { 84 return in.readInt(); 85 } 86 87 public long readLong() throws IOException { 88 return in.readLong(); 89 } 90 91 public float readFloat() throws IOException { 92 return in.readFloat(); 93 } 94 95 public double readDouble() throws IOException { 96 return in.readDouble(); 97 } 98 99 public String readUTF() throws IOException { 100 return in.readUTF(); 101 } 102 103 private DataInputStream in; 104 private ClassFile classFile; 105 private Attribute.Factory attributeFactory; 106 }