// -----------------------------------------------------------------------
// <copyright company="Apache" file="EnumerableExtensions.cs">
//
//      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
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// 
//      http://www.apache.org/licenses/LICENSE-2.0
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namespace Lucene.Net.Support
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;

    /// <summary>
    /// TODO: Update summary.
    /// </summary>
    public static class EnumerableExtensions
    {
        /// <summary>
        /// Transforms the <see cref="IEnumerable{T}"/> into a <see cref="ICharSequence"/> object.
        /// </summary>
        /// <param name="enumerable">The enumerable.</param>
        /// <returns>
        /// An instance of <see cref="ICharSequence"/>.
        /// </returns>
        public static ICharSequence ToCharSequence(this IEnumerable<char> enumerable)
        {
            // TODO: uncomment when PCL System.String implements IEnumerable<char>
            // if(enumerable is string)
            //    return new StringCharSquenceWrapper((string)enumerable); */
            char[] array = enumerable as char[];
            if (array != null)
                return new CharArrayCharSequenceWrapper(array);

            List<char> list = enumerable as List<char>;
            if (list != null)
                return new CharListCharSequenceWrapper(list);

            return new CharEnumerableCharSequenceWrapper(enumerable);
        }
    }
}