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