/*

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

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

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

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

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

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

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

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.LocalVariableGen;

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

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

/**

 * @author Jacek Ambroziak

 * @author Santiago Pericas-Geertsen

 */

public final class CompareGenerator extends MethodGenerator {

    private static int DOM_INDEX      = 1;

    private static int CURRENT_INDEX  = 2;

    private static int LEVEL_INDEX    = 3;

    private static int TRANSLET_INDEX = 4;

    private static int LAST_INDEX     = 5;

    private int ITERATOR_INDEX = 6;

    private final Instruction _iloadCurrent;

    private final Instruction _istoreCurrent;

    private final Instruction _aloadDom;

    private final Instruction _iloadLast;

    private final Instruction _aloadIterator;

    private final Instruction _astoreIterator;

    public CompareGenerator(int access_flags, Type return_type,

                            Type[] arg_types, String[] arg_names,

                            String method_name, String class_name,

                            InstructionList il, ConstantPoolGen cp) {

        super(access_flags, return_type, arg_types, arg_names, method_name,

              class_name, il, cp);

        _iloadCurrent = new ILOAD(CURRENT_INDEX);

        _istoreCurrent = new ISTORE(CURRENT_INDEX);

        _aloadDom = new ALOAD(DOM_INDEX);

        _iloadLast = new ILOAD(LAST_INDEX);

        LocalVariableGen iterator =

            addLocalVariable("iterator",

                             Util.getJCRefType(Constants.NODE_ITERATOR_SIG),

                             null, null);

        ITERATOR_INDEX = iterator.getIndex();

        _aloadIterator = new ALOAD(ITERATOR_INDEX);

        _astoreIterator = new ASTORE(ITERATOR_INDEX);

        il.append(new ACONST_NULL());

        il.append(storeIterator());

    }

    public Instruction loadLastNode() {

        return _iloadLast;

    }

    public Instruction loadCurrentNode() {

        return _iloadCurrent;

    }

    public Instruction storeCurrentNode() {

        return _istoreCurrent;

    }

    public Instruction loadDOM() {

        return _aloadDom;

    }

    public int getHandlerIndex() {

        return INVALID_INDEX;           // not available

    }

    public int getIteratorIndex() {

        return INVALID_INDEX;

    }

    public Instruction storeIterator() {

        return _astoreIterator;

    }

    public Instruction loadIterator() {

        return _aloadIterator;

    }

    //??? may not be used anymore

    public int getLocalIndex(String name) {

        if (name.equals("current")) {

            return CURRENT_INDEX;

        }

        return super.getLocalIndex(name);

    }

}