/*
 * 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 org.apache.lucene.util.mutable;

MutableValue implementation of type int.
When mutating instances of this object, the caller is responsible for ensuring 
that any instance where exists is set to false must also 
value set to 0 for proper operation.
/**
 * {@link MutableValue} implementation of type <code>int</code>.
 * When mutating instances of this object, the caller is responsible for ensuring 
 * that any instance where <code>exists</code> is set to <code>false</code> must also 
 * <code>value</code> set to <code>0</code> for proper operation.
 */
public class MutableValueInt extends MutableValue {
  public int value;
  
  @Override
  public Object toObject() {
    assert exists || 0 == value;
    return exists ? value : null;
  }

  @Override
  public void copy(MutableValue source) {
    MutableValueInt s = (MutableValueInt) source;
    value = s.value;
    exists = s.exists;
  }

  @Override
  public MutableValue duplicate() {
    MutableValueInt v = new MutableValueInt();
    v.value = this.value;
    v.exists = this.exists;
    return v;
  }

  @Override
  public boolean equalsSameType(Object other) {
    assert exists || 0 == value;
    MutableValueInt b = (MutableValueInt)other;
    return value == b.value && exists == b.exists;
  }

  @Override
  public int compareSameType(Object other) {
    assert exists || 0 == value;
    MutableValueInt b = (MutableValueInt)other;
    int ai = value;
    int bi = b.value;
    if (ai<bi) return -1;
    else if (ai>bi) return 1;

    if (exists == b.exists) return 0;
    return exists ? 1 : -1;
  }


  @Override
  public int hashCode() {
    assert exists || 0 == value;
    // TODO: if used in HashMap, it already mixes the value... maybe use a straight value?
    return (value>>8) + (value>>16);
  }
}