/*

 * 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.

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

import java.io.DataOutputStream;

import java.io.IOException;

import com.sun.org.apache.bcel.internal.Const;

import com.sun.org.apache.bcel.internal.ExceptionConst;

import com.sun.org.apache.bcel.internal.classfile.ConstantPool;

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

/**

 * INVOKEINTERFACE - Invoke interface method

 * <PRE>Stack: ..., objectref, [arg1, [arg2 ...]] -&gt; ...</PRE>

 *

 * @version $Id: INVOKEINTERFACE.java 1747278 2016-06-07 17:28:43Z britter $

 * @see

 * <a href="http://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokeinterface">

 * The invokeinterface instruction in The Java Virtual Machine Specification</a>

 */

public final class INVOKEINTERFACE extends InvokeInstruction {

    private int nargs; // Number of arguments on stack (number of stack slots), called "count" in vmspec2

    /**

     * Empty constructor needed for the Class.newInstance() statement in

     * Instruction.readInstruction(). Not to be used otherwise.

     */

    INVOKEINTERFACE() {

    }

    public INVOKEINTERFACE(final int index, final int nargs) {

        super(Const.INVOKEINTERFACE, index);

        super.setLength(5);

        if (nargs < 1) {

            throw new ClassGenException("Number of arguments must be > 0 " + nargs);

        }

        this.nargs = nargs;

    }

    /**

     * Dump instruction as byte code to stream out.

     * @param out Output stream

     */

    @Override

    public void dump( final DataOutputStream out ) throws IOException {

        out.writeByte(super.getOpcode());

        out.writeShort(super.getIndex());

        out.writeByte(nargs);

        out.writeByte(0);

    }

    /**

     * The <B>count</B> argument according to the Java Language Specification,

     * Second Edition.

     */

    public int getCount() {

        return nargs;

    }

    /**

     * Read needed data (i.e., index) from file.

     */

    @Override

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

        super.initFromFile(bytes, wide);

        super.setLength(5);

        nargs = bytes.readUnsignedByte();

        bytes.readByte(); // Skip 0 byte

    }

    /**

     * @return mnemonic for instruction with symbolic references resolved

     */

    @Override

    public String toString( final ConstantPool cp ) {

        return super.toString(cp) + " " + nargs;

    }

    @Override

    public int consumeStack( final ConstantPoolGen cpg ) { // nargs is given in byte-code

        return nargs; // nargs includes this reference

    }

    @Override

    public Class<?>[] getExceptions() {

        return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION,

            ExceptionConst.UNSATISFIED_LINK_ERROR,

            ExceptionConst.ABSTRACT_METHOD_ERROR,

            ExceptionConst.ILLEGAL_ACCESS_ERROR,

            ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR);

    }

    /**

     * 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.visitExceptionThrower(this);

        v.visitTypedInstruction(this);

        v.visitStackConsumer(this);

        v.visitStackProducer(this);

        v.visitLoadClass(this);

        v.visitCPInstruction(this);

        v.visitFieldOrMethod(this);

        v.visitInvokeInstruction(this);

        v.visitINVOKEINTERFACE(this);

    }

}