
/* ====================================================================
   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.
==================================================================== */


namespace NPOI.Util
{
    using System;
    using System.Collections.Generic;

    /// <summary>
    /// A List of objects that are indexed AND keyed by an int; also allows for Getting
    /// the index of a value in the list
    /// 
    /// <p>I am happy is someone wants to re-implement this without using the
    /// internal list and hashmap. If so could you please make sure that
    /// you can add elements half way into the list and have the value-key mappings
    /// update</p>
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <remarks>@author Jason Height</remarks>
    internal class IntMapper<T>
    {
        private List<T> elements;
        private Dictionary<T, int> valueKeyMap;

        private static int _default_size = 10;

        /// <summary>
        /// create an IntMapper of default size
        /// </summary>
        public IntMapper()
            : this(_default_size)
        {
        }

        public IntMapper(int InitialCapacity)
        {
            elements = new List<T>(InitialCapacity);
            valueKeyMap = new Dictionary<T, int>(InitialCapacity);
        }

        /// <summary>
        /// Appends the specified element to the end of this list
        /// </summary>
        /// <param name="value">element to be Appended to this list.</param>
        /// <returns>return true (as per the general contract of the Collection.add method)</returns>
        public bool Add(T value)
        {
            int index = elements.Count;
            elements.Add(value);
            if (valueKeyMap.ContainsKey(value))
            {
                valueKeyMap[value] = index;
            }
            else
            {
                valueKeyMap.Add(value, index);
            }
            return true;
        }
        /// <summary>
        /// Gets the size.
        /// </summary>
        public int Size
        {
            get
            {
                return elements.Count;
            }
        }
        /// <summary>
        /// Gets the T object at the specified index.
        /// </summary>
        /// <param name="index"></param>
        /// <returns></returns>
        public T this[int index]
        {
            get { return elements[index]; }
        }
        /// <summary>
        /// Gets the index of T object.
        /// </summary>
        /// <param name="o">The o.</param>
        /// <returns></returns>
        public int GetIndex(T o)
        {
            if (!valueKeyMap.ContainsKey(o))
                return -1;
            return valueKeyMap[o];
            /*
            int i = valueKeyMap[(o)];
            if (i == null)
                return -1;
            return i;*/
        }
        /// <summary>
        /// Gets the enumerator.
        /// </summary>
        /// <returns></returns>
        public IEnumerator<T> GetEnumerator()
        {
            return elements.GetEnumerator();
        }
    }   // end internal class IntMapper


}