001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 *
017 */
018package org.apache.bcel.generic;
019
020import java.io.DataOutputStream;
021import java.io.IOException;
022
023/** 
024 * JSR - Jump to subroutine
025 *
026 * @version $Id: JSR.java 1749603 2016-06-21 20:50:19Z ggregory $
027 */
028public class JSR extends JsrInstruction implements VariableLengthInstruction {
029
030    /**
031     * Empty constructor needed for the Class.newInstance() statement in
032     * Instruction.readInstruction(). Not to be used otherwise.
033     */
034    JSR() {
035    }
036
037
038    public JSR(final InstructionHandle target) {
039        super(org.apache.bcel.Const.JSR, target);
040    }
041
042
043    /**
044     * Dump instruction as byte code to stream out.
045     * @param out Output stream
046     */
047    @Override
048    public void dump( final DataOutputStream out ) throws IOException {
049        super.setIndex(getTargetOffset());
050        if (super.getOpcode() == org.apache.bcel.Const.JSR) {
051            super.dump(out);
052        } else { // JSR_W
053            super.setIndex(getTargetOffset());
054            out.writeByte(super.getOpcode());
055            out.writeInt(super.getIndex());
056        }
057    }
058
059
060    @Override
061    protected int updatePosition( final int offset, final int max_offset ) {
062        final int i = getTargetOffset(); // Depending on old position value
063        setPosition(getPosition() + offset); // Position may be shifted by preceding expansions
064        if (Math.abs(i) >= (Short.MAX_VALUE - max_offset)) { // to large for short (estimate)
065            super.setOpcode(org.apache.bcel.Const.JSR_W);
066            final short old_length = (short) super.getLength();
067            super.setLength(5);
068            return super.getLength() - old_length;
069        }
070        return 0;
071    }
072
073
074    /**
075     * Call corresponding visitor method(s). The order is:
076     * Call visitor methods of implemented interfaces first, then
077     * call methods according to the class hierarchy in descending order,
078     * i.e., the most specific visitXXX() call comes last.
079     *
080     * @param v Visitor object
081     */
082    @Override
083    public void accept( final Visitor v ) {
084        v.visitStackProducer(this);
085        v.visitVariableLengthInstruction(this);
086        v.visitBranchInstruction(this);
087        v.visitJsrInstruction(this);
088        v.visitJSR(this);
089    }
090}