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/*
* 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 org.apache.bcel.generic;
import java.io.DataOutputStream;
import java.io.IOException;
import org.apache.bcel.ExceptionConst;
import org.apache.bcel.util.ByteSequence;
/**
* LDC - Push item from constant pool.
*
* <PRE>Stack: ... -> ..., item</PRE>
*
* @version $Id$
*/
public class LDC extends CPInstruction implements PushInstruction, ExceptionThrower {
/**
* Empty constructor needed for Instruction.readInstruction.
* Not to be used otherwise.
*/
LDC() {
}
public LDC(final int index) {
super(org.apache.bcel.Const.LDC_W, index);
setSize();
}
// Adjust to proper size
protected final void setSize() {
if (super.getIndex() <= org.apache.bcel.Const.MAX_BYTE) { // Fits in one byte?
super.setOpcode(org.apache.bcel.Const.LDC);
super.setLength(2);
} else {
super.setOpcode(org.apache.bcel.Const.LDC_W);
super.setLength(3);
}
}
/**
* 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.
*/
@Override
public final void setIndex( final int index ) {
super.setIndex(index);
setSize();
}
/**
* 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 ) {
org.apache.bcel.classfile.Constant c = cpg.getConstantPool().getConstant(super.getIndex());
switch (c.getTag()) {
case org.apache.bcel.Const.CONSTANT_String:
final int i = ((org.apache.bcel.classfile.ConstantString) c).getStringIndex();
c = cpg.getConstantPool().getConstant(i);
return ((org.apache.bcel.classfile.ConstantUtf8) c).getBytes();
case org.apache.bcel.Const.CONSTANT_Float:
return new Float(((org.apache.bcel.classfile.ConstantFloat) c).getBytes());
case org.apache.bcel.Const.CONSTANT_Integer:
return Integer.valueOf(((org.apache.bcel.classfile.ConstantInteger) c).getBytes());
case org.apache.bcel.Const.CONSTANT_Class:
final int nameIndex = ((org.apache.bcel.classfile.ConstantClass) c).getNameIndex();
c = cpg.getConstantPool().getConstant(nameIndex);
return new ObjectType(((org.apache.bcel.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 org.apache.bcel.Const.CONSTANT_String:
return Type.STRING;
case org.apache.bcel.Const.CONSTANT_Float:
return Type.FLOAT;
case org.apache.bcel.Const.CONSTANT_Integer:
return Type.INT;
case org.apache.bcel.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.
*
* @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);
}
}
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