/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2014 Eric Lafortune (eric@graphics.cornell.edu)
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.attribute.preverification;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.attribute.preverification.visitor.VerificationTypeVisitor;

/**
 * This VerificationType represents a Null type.
 *
 * @author Eric Lafortune
 */
public class NullType extends VerificationType
{
    // Implementations for VerificationType.

    public int getTag()
    {
        return NULL_TYPE;
    }


    public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, VerificationTypeVisitor verificationTypeVisitor)
    {
        verificationTypeVisitor.visitNullType(clazz, method, codeAttribute, instructionOffset, this);
    }


    public void stackAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, int stackIndex, VerificationTypeVisitor verificationTypeVisitor)
    {
        verificationTypeVisitor.visitStackNullType(clazz, method, codeAttribute, instructionOffset, stackIndex, this);
    }


    public void variablesAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, int variableIndex, VerificationTypeVisitor verificationTypeVisitor)
    {
        verificationTypeVisitor.visitVariablesNullType(clazz, method, codeAttribute, instructionOffset, variableIndex, this);
    }


    // Implementations for Object.

    public String toString()
    {
        return "n";
    }
}