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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;
/**
* GOTO - Branch always (to relative offset, not absolute address)
*
* @version $Id$
*/
public class GOTO extends GotoInstruction implements VariableLengthInstruction {
/**
* Empty constructor needed for the Class.newInstance() statement in
* Instruction.readInstruction(). Not to be used otherwise.
*/
GOTO() {
}
public GOTO(final InstructionHandle target) {
super(org.apache.bcel.Const.GOTO, target);
}
/**
* Dump instruction as byte code to stream out.
* @param out Output stream
*/
@Override
public void dump( final DataOutputStream out ) throws IOException {
super.setIndex(getTargetOffset());
final short _opcode = getOpcode();
if (_opcode == org.apache.bcel.Const.GOTO) {
super.dump(out);
} else { // GOTO_W
super.setIndex(getTargetOffset());
out.writeByte(_opcode);
out.writeInt(super.getIndex());
}
}
/**
* Called in pass 2 of InstructionList.setPositions() in order to update
* the branch target, that may shift due to variable length instructions.
*
* @param offset additional offset caused by preceding (variable length) instructions
* @param max_offset the maximum offset that may be caused by these instructions
* @return additional offset caused by possible change of this instruction's length
*/
@Override
protected int updatePosition( final int offset, final int max_offset ) {
final int i = getTargetOffset(); // Depending on old position value
setPosition(getPosition() + offset); // Position may be shifted by preceding expansions
if (Math.abs(i) >= (Short.MAX_VALUE - max_offset)) { // to large for short (estimate)
super.setOpcode(org.apache.bcel.Const.GOTO_W);
final short old_length = (short) super.getLength();
super.setLength(5);
return super.getLength() - old_length;
}
return 0;
}
/**
* 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.visitVariableLengthInstruction(this);
v.visitUnconditionalBranch(this);
v.visitBranchInstruction(this);
v.visitGotoInstruction(this);
v.visitGOTO(this);
}
}
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