/* * reserved comment block * DO NOT REMOVE OR ALTER! */ /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.sun.org.apache.bcel.internal.generic; import java.io.*; import com.sun.org.apache.bcel.internal.util.ByteSequence; /** * LDC - Push item from constant pool. * *
Stack: ... -> ..., item* * @author M. Dahm */ public class LDC extends CPInstruction implements PushInstruction, ExceptionThrower, TypedInstruction { /** * Empty constructor needed for the Class.newInstance() statement in * Instruction.readInstruction(). Not to be used otherwise. */ LDC() {} public LDC(int index) { super(com.sun.org.apache.bcel.internal.Constants.LDC_W, index); setSize(); } // Adjust to proper size protected final void setSize() { if(index <= com.sun.org.apache.bcel.internal.Constants.MAX_BYTE) { // Fits in one byte? opcode = com.sun.org.apache.bcel.internal.Constants.LDC; length = 2; } else { opcode = com.sun.org.apache.bcel.internal.Constants.LDC_W; length = 3; } } /** * Dump instruction as byte code to stream out. * @param out Output stream */ public void dump(DataOutputStream out) throws IOException { out.writeByte(opcode); if(length == 2) out.writeByte(index); else // Applies for LDC_W out.writeShort(index); } /** * Set the index to constant pool and adjust size. */ public final void setIndex(int index) { super.setIndex(index); setSize(); } /** * Read needed data (e.g. index) from file. */ protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException { length = 2; index = bytes.readUnsignedByte(); } public Object getValue(ConstantPoolGen cpg) { com.sun.org.apache.bcel.internal.classfile.Constant c = cpg.getConstantPool().getConstant(index); switch(c.getTag()) { case com.sun.org.apache.bcel.internal.Constants.CONSTANT_String: int i = ((com.sun.org.apache.bcel.internal.classfile.ConstantString)c).getStringIndex(); c = cpg.getConstantPool().getConstant(i); return ((com.sun.org.apache.bcel.internal.classfile.ConstantUtf8)c).getBytes(); case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Float: return new Float(((com.sun.org.apache.bcel.internal.classfile.ConstantFloat)c).getBytes()); case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Integer: return new Integer(((com.sun.org.apache.bcel.internal.classfile.ConstantInteger)c).getBytes()); default: // Never reached throw new RuntimeException("Unknown or invalid constant type at " + index); } } public Type getType(ConstantPoolGen cpg) { switch(cpg.getConstantPool().getConstant(index).getTag()) { case com.sun.org.apache.bcel.internal.Constants.CONSTANT_String: return Type.STRING; case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Float: return Type.FLOAT; case com.sun.org.apache.bcel.internal.Constants.CONSTANT_Integer: return Type.INT; default: // Never reached throw new RuntimeException("Unknown or invalid constant type at " + index); } } public Class[] getExceptions() { return com.sun.org.apache.bcel.internal.ExceptionConstants.EXCS_STRING_RESOLUTION; } /** * Call corresponding visitor method(s). The order is: * Call visitor methods of implemented interfaces first, then * call methods according to the class hierarchy in descending order, * i.e., the most specific visitXXX() call comes last. * * @param v Visitor object */ public void accept(Visitor v) { v.visitStackProducer(this); v.visitPushInstruction(this); v.visitExceptionThrower(this); v.visitTypedInstruction(this); v.visitCPInstruction(this); v.visitLDC(this); } }