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1 package org.apache.bcel.generic; 2 3 /* ==================================================================== 4 * The Apache Software License, Version 1.1 5 * 6 * Copyright (c) 2001 The Apache Software Foundation. All rights 7 * reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. The end-user documentation included with the redistribution, 22 * if any, must include the following acknowledgment: 23 * "This product includes software developed by the 24 * Apache Software Foundation (http://www.apache.org/)." 25 * Alternately, this acknowledgment may appear in the software itself, 26 * if and wherever such third-party acknowledgments normally appear. 27 * 28 * 4. The names "Apache" and "Apache Software Foundation" and 29 * "Apache BCEL" must not be used to endorse or promote products 30 * derived from this software without prior written permission. For 31 * written permission, please contact apache@apache.org. 32 * 33 * 5. Products derived from this software may not be called "Apache", 34 * "Apache BCEL", nor may "Apache" appear in their name, without 35 * prior written permission of the Apache Software Foundation. 36 * 37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 48 * SUCH DAMAGE. 49 * ==================================================================== 50 * 51 * This software consists of voluntary contributions made by many 52 * individuals on behalf of the Apache Software Foundation. For more 53 * information on the Apache Software Foundation, please see 54 * <http://www.apache.org/>;. 55 */ 56 import java.io.*; 57 import org.apache.bcel.util.ByteSequence; 58 59 /*** 60 * LDC - Push item from constant pool. 61 * 62 * <PRE>Stack: ... -> ..., item</PRE> 63 * 64 * @version $Id: LDC.java,v 1.1.1.1 2001/10/29 20:00:21 jvanzyl Exp $ 65 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> 66 */ 67 public class LDC extends CPInstruction 68 implements PushInstruction, ExceptionThrower, TypedInstruction { 69 /*** 70 * Empty constructor needed for the Class.newInstance() statement in 71 * Instruction.readInstruction(). Not to be used otherwise. 72 */ 73 LDC() {} 74 75 public LDC(int index) { 76 super(org.apache.bcel.Constants.LDC_W, index); 77 setSize(); 78 } 79 80 // Adjust to proper size 81 protected final void setSize() { 82 if(index <= org.apache.bcel.Constants.MAX_BYTE) { // Fits in one byte? 83 opcode = org.apache.bcel.Constants.LDC; 84 length = 2; 85 } else { 86 opcode = org.apache.bcel.Constants.LDC_W; 87 length = 3; 88 } 89 } 90 91 /*** 92 * Dump instruction as byte code to stream out. 93 * @param out Output stream 94 */ 95 public void dump(DataOutputStream out) throws IOException { 96 out.writeByte(opcode); 97 98 if(length == 2) 99 out.writeByte(index); 100 else // Applies for LDC_W 101 out.writeShort(index); 102 } 103 104 /*** 105 * Set the index to constant pool and adjust size. 106 */ 107 public final void setIndex(int index) { 108 super.setIndex(index); 109 setSize(); 110 } 111 112 /*** 113 * Read needed data (e.g. index) from file. 114 */ 115 protected void initFromFile(ByteSequence bytes, boolean wide) 116 throws IOException 117 { 118 length = 2; 119 index = bytes.readUnsignedByte(); 120 } 121 122 public Object getValue(ConstantPoolGen cpg) { 123 org.apache.bcel.classfile.Constant c = cpg.getConstantPool().getConstant(index); 124 125 switch(c.getTag()) { 126 case org.apache.bcel.Constants.CONSTANT_String: 127 int i = ((org.apache.bcel.classfile.ConstantString)c).getStringIndex(); 128 c = cpg.getConstantPool().getConstant(i); 129 return ((org.apache.bcel.classfile.ConstantUtf8)c).getBytes(); 130 131 case org.apache.bcel.Constants.CONSTANT_Float: 132 return new Float(((org.apache.bcel.classfile.ConstantFloat)c).getBytes()); 133 134 case org.apache.bcel.Constants.CONSTANT_Integer: 135 return new Integer(((org.apache.bcel.classfile.ConstantInteger)c).getBytes()); 136 137 default: // Never reached 138 throw new RuntimeException("Unknown or invalid constant type at " + index); 139 } 140 } 141 142 public Type getType(ConstantPoolGen cpg) { 143 switch(cpg.getConstantPool().getConstant(index).getTag()) { 144 case org.apache.bcel.Constants.CONSTANT_String: return Type.STRING; 145 case org.apache.bcel.Constants.CONSTANT_Float: return Type.FLOAT; 146 case org.apache.bcel.Constants.CONSTANT_Integer: return Type.INT; 147 default: // Never reached 148 throw new RuntimeException("Unknown or invalid constant type at " + index); 149 } 150 } 151 152 public Class[] getExceptions() { 153 return org.apache.bcel.ExceptionConstants.EXCS_STRING_RESOLUTION; 154 } 155 156 /*** 157 * Call corresponding visitor method(s). The order is: 158 * Call visitor methods of implemented interfaces first, then 159 * call methods according to the class hierarchy in descending order, 160 * i.e., the most specific visitXXX() call comes last. 161 * 162 * @param v Visitor object 163 */ 164 public void accept(Visitor v) { 165 v.visitStackProducer(this); 166 v.visitPushInstruction(this); 167 v.visitExceptionThrower(this); 168 v.visitTypedInstruction(this); 169 v.visitCPInstruction(this); 170 v.visitLDC(this); 171 } 172 }

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