Bitonic Sort for Unity C#

BitonicSort.cs

using System.Collections;
using System.Collections.Generic;
using System;
using UnityEngine;

namespace Gists
{
    public static class BitonicSort
    {
        public const float InvertLogTwo = 1f / 0.6931471805f;   // 1.0 / loge2


        public static void Sort<T>(ref T[] array, T valueForShortage = default(T)) where T : IComparable
        {
            var length = array.Length;

            if(length <= 0)
            {
                return;
            }

            CheckArrayLength(ref array, valueForShortage);
            var log = Mathf.Log(length) * InvertLogTwo;   // this.length = 2 ^ log

            for(var width = 0; width < log; width++)
            {
                for(var height = 0; height <= width; height++)
                {
                    var step = 1 << (width - height);  // 2 ^ (width - height)

                    for(var i = 0; i < length; i++)
                    {
                        var skip = i & step;   // d間隔で0とdを繰り返す

                        // i >> width = width * 2間隔で0,1,2,3とインクリメントさせていく
                        var up = ((i >> width) & 2) == 0;   // width * 2 * 2間隔で0と2を繰り返す

                        if(skip == 0 && (array[i].CompareTo(array[i + step]) > 0) == up)
                        {
                            var tmp = array[i];
                            array[i] = array[i + step];
                            array[i + step] = tmp;
                        }
                    }
                }
            }
        }

        public static void CheckArrayLength<T>(ref T[] array, T valueForShortage)
        {
            var length = array.Length;

            if(length <= 0 || Mathf.IsPowerOfTwo(length) == true)
            {
                return;
            }

            var shortage = Mathf.NextPowerOfTwo(length) - length;
            var arr = new T[length + shortage];

            Array.Copy(array, arr, length);
            for(var i = length; i < arr.Length; i++)
            {
                arr[i] = valueForShortage;
            }

            array = arr;
        }
    }
}