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 */
027public class JSR extends JsrInstruction implements VariableLengthInstruction {
028
029    /**
030     * Empty constructor needed for Instruction.readInstruction.
031     * Not to be used otherwise.
032     */
033    JSR() {
034    }
035
036
037    public JSR(final InstructionHandle target) {
038        super(org.apache.bcel.Const.JSR, target);
039    }
040
041
042    /**
043     * Dump instruction as byte code to stream out.
044     * @param out Output stream
045     */
046    @Override
047    public void dump( final DataOutputStream out ) throws IOException {
048        super.setIndex(getTargetOffset());
049        if (super.getOpcode() == org.apache.bcel.Const.JSR) {
050            super.dump(out);
051        } else { // JSR_W
052            super.setIndex(getTargetOffset());
053            out.writeByte(super.getOpcode());
054            out.writeInt(super.getIndex());
055        }
056    }
057
058
059    @Override
060    protected int updatePosition( final int offset, final int max_offset ) {
061        final int i = getTargetOffset(); // Depending on old position value
062        setPosition(getPosition() + offset); // Position may be shifted by preceding expansions
063        if (Math.abs(i) >= (Short.MAX_VALUE - max_offset)) { // to large for short (estimate)
064            super.setOpcode(org.apache.bcel.Const.JSR_W);
065            final short old_length = (short) super.getLength();
066            super.setLength(5);
067            return super.getLength() - old_length;
068        }
069        return 0;
070    }
071
072
073    /**
074     * Call corresponding visitor method(s). The order is:
075     * Call visitor methods of implemented interfaces first, then
076     * call methods according to the class hierarchy in descending order,
077     * i.e., the most specific visitXXX() call comes last.
078     *
079     * @param v Visitor object
080     */
081    @Override
082    public void accept( final Visitor v ) {
083        v.visitStackProducer(this);
084        v.visitVariableLengthInstruction(this);
085        v.visitBranchInstruction(this);
086        v.visitJsrInstruction(this);
087        v.visitJSR(this);
088    }
089}