/*

 * 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;

import com.sun.org.apache.bcel.internal.util.ByteSequence;

/**

 * RET - Return from subroutine

 *

 * <PRE>Stack: ... -&gt; ...</PRE>

 *

 */

public class RET extends Instruction implements IndexedInstruction, TypedInstruction {

    private boolean wide;

    private int index; // index to local variable containg the return address

    /**

     * Empty constructor needed for Instruction.readInstruction.

     * Not to be used otherwise.

     */

    RET() {

    }

    public RET(final int index) {

        super(com.sun.org.apache.bcel.internal.Const.RET, (short) 2);

        setIndex(index); // May set wide as side effect

    }

    /**

     * Dump instruction as byte code to stream out.

     * @param out Output stream

     */

    @Override

    public void dump( final DataOutputStream out ) throws IOException {

        if (wide) {

            out.writeByte(com.sun.org.apache.bcel.internal.Const.WIDE);

        }

        out.writeByte(super.getOpcode());

        if (wide) {

            out.writeShort(index);

        } else {

            out.writeByte(index);

        }

    }

    private void setWide() {

        wide = index > com.sun.org.apache.bcel.internal.Const.MAX_BYTE;

        if (wide) {

            super.setLength(4); // Including the wide byte

        } else {

            super.setLength(2);

        }

    }

    /**

     * Read needed data (e.g. index) from file.

     */

    @Override

    protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException {

        this.wide = wide;

        if (wide) {

            index = bytes.readUnsignedShort();

            super.setLength(4);

        } else {

            index = bytes.readUnsignedByte();

            super.setLength(2);

        }

    }

    /**

     * @return index of local variable containg the return address

     */

    @Override

    public final int getIndex() {

        return index;

    }

    /**

     * Set index of local variable containg the return address

     */

    @Override

    public final void setIndex( final int n ) {

        if (n < 0) {

            throw new ClassGenException("Negative index value: " + n);

        }

        index = n;

        setWide();

    }

    /**

     * @return mnemonic for instruction

     */

    @Override

    public String toString( final boolean verbose ) {

        return super.toString(verbose) + " " + index;

    }

    /** @return return address type

     */

    @Override

    public Type getType( final ConstantPoolGen cp ) {

        return ReturnaddressType.NO_TARGET;

    }

    /**

     * 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.visitRET(this);

    }

}