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/***

 * ASM: a very small and fast Java bytecode manipulation framework

 * Copyright (c) 2000-2005 INRIA, France Telecom

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the copyright holders nor the names of its

 *    contributors may be used to endorse or promote products derived from

 *    this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

 * THE POSSIBILITY OF SUCH DAMAGE.

 */

package org.objectweb.asm;

/**

 * A constant pool item. Constant pool items can be created with the 'newXXX'

 * methods in the {@link ClassWriter} class.

 *

 * @author Eric Bruneton

 */

final class Item {

    /**

     * Index of this item in the constant pool.

     */

    int index;

    /**

     * Type of this constant pool item. A single class is used to represent all

     * constant pool item types, in order to minimize the bytecode size of this

     * package. The value of this field is one of {@link ClassWriter#INT},

     * {@link ClassWriter#LONG}, {@link ClassWriter#FLOAT},

     * {@link ClassWriter#DOUBLE}, {@link ClassWriter#UTF8},

     * {@link ClassWriter#STR}, {@link ClassWriter#CLASS},

     * {@link ClassWriter#NAME_TYPE}, {@link ClassWriter#FIELD},

     * {@link ClassWriter#METH}, {@link ClassWriter#IMETH}.

     */

    int type;

    /**

     * Value of this item, for an integer item.

     */

    int intVal;

    /**

     * Value of this item, for a long item.

     */

    long longVal;

    /**

     * Value of this item, for a float item.

     */

    float floatVal;

    /**

     * Value of this item, for a double item.

     */

    double doubleVal;

    /**

     * First part of the value of this item, for items that do not hold a

     * primitive value.

     */

    String strVal1;

    /**

     * Second part of the value of this item, for items that do not hold a

     * primitive value.

     */

    String strVal2;

    /**

     * Third part of the value of this item, for items that do not hold a

     * primitive value.

     */

    String strVal3;

    /**

     * The hash code value of this constant pool item.

     */

    int hashCode;

    /**

     * Link to another constant pool item, used for collision lists in the

     * constant pool's hash table.

     */

    Item next;

    /**

     * Constructs an uninitialized {@link Item}.

     */

    Item() {

    }

    Item(int index) {

        this.index = index;

    }

    /**

     * Constructs a copy of the given item.

     *

     * @param index index of the item to be constructed.

     * @param i the item that must be copied into the item to be constructed.

     */

    Item(final int index, final Item i) {

        this.index = index;

        type = i.type;

        intVal = i.intVal;

        longVal = i.longVal;

        floatVal = i.floatVal;

        doubleVal = i.doubleVal;

        strVal1 = i.strVal1;

        strVal2 = i.strVal2;

        strVal3 = i.strVal3;

        hashCode = i.hashCode;

    }

    /**

     * Sets this item to an integer item.

     *

     * @param intVal the value of this item.

     */

    void set(final int intVal) {

        this.type = ClassWriter.INT;

        this.intVal = intVal;

        this.hashCode = 0x7FFFFFFF & (type + intVal);

    }

    /**

     * Sets this item to a long item.

     *

     * @param longVal the value of this item.

     */

    void set(final long longVal) {

        this.type = ClassWriter.LONG;

        this.longVal = longVal;

        this.hashCode = 0x7FFFFFFF & (type + (int) longVal);

    }

    /**

     * Sets this item to a float item.

     *

     * @param floatVal the value of this item.

     */

    void set(final float floatVal) {

        this.type = ClassWriter.FLOAT;

        this.floatVal = floatVal;

        this.hashCode = 0x7FFFFFFF & (type + (int) floatVal);

    }

    /**

     * Sets this item to a double item.

     *

     * @param doubleVal the value of this item.

     */

    void set(final double doubleVal) {

        this.type = ClassWriter.DOUBLE;

        this.doubleVal = doubleVal;

        this.hashCode = 0x7FFFFFFF & (type + (int) doubleVal);

    }

    /**

     * Sets this item to an item that do not hold a primitive value.

     *

     * @param type the type of this item.

     * @param strVal1 first part of the value of this item.

     * @param strVal2 second part of the value of this item.

     * @param strVal3 third part of the value of this item.

     */

    void set(

        final int type,

        final String strVal1,

        final String strVal2,

        final String strVal3)

    {

        this.type = type;

        this.strVal1 = strVal1;

        this.strVal2 = strVal2;

        this.strVal3 = strVal3;

        switch (type) {

            case ClassWriter.UTF8:

            case ClassWriter.STR:

            case ClassWriter.CLASS:

                hashCode = 0x7FFFFFFF & (type + strVal1.hashCode());

                return;

            case ClassWriter.NAME_TYPE:

                hashCode = 0x7FFFFFFF & (type + strVal1.hashCode()

                        * strVal2.hashCode());

                return;

            // ClassWriter.FIELD:

            // ClassWriter.METH:

            // ClassWriter.IMETH:

            default:

                hashCode = 0x7FFFFFFF & (type + strVal1.hashCode()

                        * strVal2.hashCode() * strVal3.hashCode());

        }

    }

    /**

     * Indicates if the given item is equal to this one.

     *

     * @param i the item to be compared to this one.

     * @return <tt>true</tt> if the given item if equal to this one,

     *         <tt>false</tt> otherwise.

     */

    boolean isEqualTo(final Item i) {

        if (i.type == type) {

            switch (type) {

                case ClassWriter.INT:

                    return i.intVal == intVal;

                case ClassWriter.LONG:

                    return i.longVal == longVal;

                case ClassWriter.FLOAT:

                    return i.floatVal == floatVal;

                case ClassWriter.DOUBLE:

                    return i.doubleVal == doubleVal;

                case ClassWriter.UTF8:

                case ClassWriter.STR:

                case ClassWriter.CLASS:

                    return i.strVal1.equals(strVal1);

                case ClassWriter.NAME_TYPE:

                    return i.strVal1.equals(strVal1)

                            && i.strVal2.equals(strVal2);

                // ClassWriter.FIELD:

                // ClassWriter.METH:

                // ClassWriter.IMETH:

                default:

                    return i.strVal1.equals(strVal1)

                            && i.strVal2.equals(strVal2)

                            && i.strVal3.equals(strVal3);

            }

        }

        return false;

    }

}