/*

 */

/*

 * 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.xalan.internal.xsltc.compiler.util;

import com.sun.org.apache.bcel.internal.generic.Instruction;

import com.sun.org.apache.bcel.internal.generic.InstructionList;

import com.sun.org.apache.bcel.internal.generic.PUSH;

import com.sun.org.apache.xalan.internal.xsltc.compiler.Constants;

/**

 * @author Jacek Ambroziak

 * @author Santiago Pericas-Geertsen

 */

public final class VoidType extends Type {

    protected VoidType() {}

    public String toString() {

        return "void";

    }

    public boolean identicalTo(Type other) {

        return this == other;

    }

    public String toSignature() {

        return "V";

    }

    public com.sun.org.apache.bcel.internal.generic.Type toJCType() {

        return null;    // should never be called

    }

    public Instruction POP() {

        return NOP;

    }

    /**

     * Translates a void into an object of internal type <code>type</code>.

     * This translation is needed when calling external functions

     * that return void.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo

     */

    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,

                            Type type) {

        if (type == Type.String) {

            translateTo(classGen, methodGen, (StringType) type);

        }

        else {

            ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,

                                        toString(), type.toString());

            classGen.getParser().reportError(Constants.FATAL, err);

        }

    }

    /**

     * Translates a void into a string by pushing the empty string ''.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo

     */

    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,

                            StringType type) {

        final InstructionList il = methodGen.getInstructionList();

        il.append(new PUSH(classGen.getConstantPool(), ""));

    }

    /**

     * Translates an external (primitive) Java type into a void.

     * Only an external "void" can be converted to this class.

     */

    public void translateFrom(ClassGenerator classGen, MethodGenerator methodGen,

        if (!clazz.getName().equals("void")) {

            ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,

                                        toString(), clazz.getName());

            classGen.getParser().reportError(Constants.FATAL, err);

        }

    }

}