/*
 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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,
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 * See the License for the specific language governing permissions and
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package com.sun.org.apache.bcel.internal.generic;

import java.io.DataOutputStream;
import java.io.IOException;

import com.sun.org.apache.bcel.internal.ExceptionConst;
import com.sun.org.apache.bcel.internal.util.ByteSequence;

LDC - Push item from constant pool.
Stack: ... -> ..., item
Version:$Id: LDC.java 1749603 2016-06-21 20:50:19Z ggregory $
@LastModified: Nov 2017
/** * LDC - Push item from constant pool. * * <PRE>Stack: ... -&gt; ..., item</PRE> * * @version $Id: LDC.java 1749603 2016-06-21 20:50:19Z ggregory $ * @LastModified: Nov 2017 */
public class LDC extends CPInstruction implements PushInstruction, ExceptionThrower {
Empty constructor needed for the Class.newInstance() statement in Instruction.readInstruction(). Not to be used otherwise.
/** * Empty constructor needed for the Class.newInstance() statement in * Instruction.readInstruction(). Not to be used otherwise. */
LDC() { } public LDC(final int index) { super(com.sun.org.apache.bcel.internal.Const.LDC_W, index); setSize(); } // Adjust to proper size protected final void setSize() { if (super.getIndex() <= com.sun.org.apache.bcel.internal.Const.MAX_BYTE) { // Fits in one byte? super.setOpcode(com.sun.org.apache.bcel.internal.Const.LDC); super.setLength(2); } else { super.setOpcode(com.sun.org.apache.bcel.internal.Const.LDC_W); super.setLength(3); } }
Dump instruction as byte code to stream out.
Params:
  • out – Output stream
/** * Dump instruction as byte code to stream out. * @param out Output stream */
@Override public void dump( final DataOutputStream out ) throws IOException { out.writeByte(super.getOpcode()); if (super.getLength() == 2) { // TODO useless check? out.writeByte(super.getIndex()); } else { out.writeShort(super.getIndex()); } }
Set the index to constant pool and adjust size.
/** * Set the index to constant pool and adjust size. */
@Override public final void setIndex( final int index ) { super.setIndex(index); setSize(); }
Read needed data (e.g. index) from file.
/** * Read needed data (e.g. index) from file. */
@Override protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException { super.setLength(2); super.setIndex(bytes.readUnsignedByte()); } public Object getValue( final ConstantPoolGen cpg ) { com.sun.org.apache.bcel.internal.classfile.Constant c = cpg.getConstantPool().getConstant(super.getIndex()); switch (c.getTag()) { case com.sun.org.apache.bcel.internal.Const.CONSTANT_String: final 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.Const.CONSTANT_Float: return ((com.sun.org.apache.bcel.internal.classfile.ConstantFloat) c).getBytes(); case com.sun.org.apache.bcel.internal.Const.CONSTANT_Integer: return ((com.sun.org.apache.bcel.internal.classfile.ConstantInteger) c).getBytes(); case com.sun.org.apache.bcel.internal.Const.CONSTANT_Class: final int nameIndex = ((com.sun.org.apache.bcel.internal.classfile.ConstantClass) c).getNameIndex(); c = cpg.getConstantPool().getConstant(nameIndex); return new ObjectType(((com.sun.org.apache.bcel.internal.classfile.ConstantUtf8) c).getBytes()); default: // Never reached throw new RuntimeException("Unknown or invalid constant type at " + super.getIndex()); } } @Override public Type getType( final ConstantPoolGen cpg ) { switch (cpg.getConstantPool().getConstant(super.getIndex()).getTag()) { case com.sun.org.apache.bcel.internal.Const.CONSTANT_String: return Type.STRING; case com.sun.org.apache.bcel.internal.Const.CONSTANT_Float: return Type.FLOAT; case com.sun.org.apache.bcel.internal.Const.CONSTANT_Integer: return Type.INT; case com.sun.org.apache.bcel.internal.Const.CONSTANT_Class: return Type.CLASS; default: // Never reached throw new RuntimeException("Unknown or invalid constant type at " + super.getIndex()); } } @Override public Class<?>[] getExceptions() { return ExceptionConst.createExceptions(ExceptionConst.EXCS.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.
Params:
  • v – Visitor object
/** * 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 */
@Override public void accept( final Visitor v ) { v.visitStackProducer(this); v.visitPushInstruction(this); v.visitExceptionThrower(this); v.visitTypedInstruction(this); v.visitCPInstruction(this); v.visitLDC(this); } }