/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.bcel.internal.generic;

import java.io.DataOutputStream;

import java.io.IOException;

/**

 * GOTO - Branch always (to relative offset, not absolute address)

 *

 */

public class GOTO extends GotoInstruction implements VariableLengthInstruction {

    /**

     * Empty constructor needed for Instruction.readInstruction.

     * Not to be used otherwise.

     */

    GOTO() {

    }

    public GOTO(final InstructionHandle target) {

        super(com.sun.org.apache.bcel.internal.Const.GOTO, target);

    }

    /**

     * Dump instruction as byte code to stream out.

     * @param out Output stream

     */

    @Override

    public void dump( final DataOutputStream out ) throws IOException {

        super.setIndex(getTargetOffset());

        final short _opcode = getOpcode();

        if (_opcode == com.sun.org.apache.bcel.internal.Const.GOTO) {

            super.dump(out);

        } else { // GOTO_W

            super.setIndex(getTargetOffset());

            out.writeByte(_opcode);

            out.writeInt(super.getIndex());

        }

    }

    /**

     * Called in pass 2 of InstructionList.setPositions() in order to update

     * the branch target, that may shift due to variable length instructions.

     *

     * @param offset additional offset caused by preceding (variable length) instructions

     * @param max_offset the maximum offset that may be caused by these instructions

     * @return additional offset caused by possible change of this instruction's length

     */

    @Override

    protected int updatePosition( final int offset, final int max_offset ) {

        final int i = getTargetOffset(); // Depending on old position value

        setPosition(getPosition() + offset); // Position may be shifted by preceding expansions

        if (Math.abs(i) >= (Short.MAX_VALUE - max_offset)) { // to large for short (estimate)

            super.setOpcode(com.sun.org.apache.bcel.internal.Const.GOTO_W);

            final short old_length = (short) super.getLength();

            super.setLength(5);

            return super.getLength() - old_length;

        }

        return 0;

    }

    /**

     * Call corresponding visitor method(s). The order is:

     * Call visitor methods of implemented interfaces first, then

     * call methods according to the class hierarchy in descending order,

     * i.e., the most specific visitXXX() call comes last.

     *

     * @param v Visitor object

     */

    @Override

    public void accept( final Visitor v ) {

        v.visitVariableLengthInstruction(this);

        v.visitUnconditionalBranch(this);

        v.visitBranchInstruction(this);

        v.visitGotoInstruction(this);

        v.visitGOTO(this);

    }

}