    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}