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    /**
036     * Constructs a JSR instruction.
037     *
038     * @param target branch target.
039     */
040    public JSR(final InstructionHandle target) {
041        super(org.apache.bcel.Const.JSR, target);
042    }
043
044    /**
045     * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
046     * methods according to the class hierarchy in descending order, that is, the most specific visitXXX() call comes last.
047     *
048     * @param v Visitor object.
049     */
050    @Override
051    public void accept(final Visitor v) {
052        v.visitStackProducer(this);
053        v.visitVariableLengthInstruction(this);
054        v.visitBranchInstruction(this);
055        v.visitJsrInstruction(this);
056        v.visitJSR(this);
057    }
058
059    /**
060     * Dumps instruction as byte code to stream out.
061     *
062     * @param out Output stream.
063     */
064    @Override
065    public void dump(final DataOutputStream out) throws IOException {
066        super.setIndex(getTargetOffset());
067        if (super.getOpcode() == org.apache.bcel.Const.JSR) {
068            super.dump(out);
069        } else { // JSR_W
070            super.setIndex(getTargetOffset());
071            out.writeByte(super.getOpcode());
072            out.writeInt(super.getIndex());
073        }
074    }
075
076    @Override
077    protected int updatePosition(final int offset, final int maxOffset) {
078        final int i = getTargetOffset(); // Depending on old position value
079        setPosition(getPosition() + offset); // Position may be shifted by preceding expansions
080        if (Math.abs(i) >= Short.MAX_VALUE - maxOffset) { // to large for short (estimate)
081            super.setOpcode(org.apache.bcel.Const.JSR_W);
082            final short oldLength = (short) super.getLength();
083            super.setLength(5);
084            return super.getLength() - oldLength;
085        }
086        return 0;
087    }
088}