Duplicate songs detector via audio fingerprinting

// Sound Fingerprinting framework
// https://code.google.com/p/soundfingerprinting/
// Code license: GNU General Public License v2
// ciumac.sergiu@gmail.com

// <copyright file="Histogram.cs" company="Math.NET">
// Math.NET Numerics, part of the Math.NET Project
// http://numerics.mathdotnet.com
// http://github.com/mathnet/mathnet-numerics
// http://mathnetnumerics.codeplex.com
//
// Copyright (c) 2009-2010 Math.NET
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
// </copyright>

namespace SoundfingerprintingLib.Hashing
{
    /// <summary>
    ///   Set of tool functions.
    /// </summary>
    /// <remarks>
    ///   The class contains different utility functions.
    /// </remarks>
    public static class Tools
    {
        /// <summary>
        ///   Calculates power of 2.
        /// </summary>
        /// <param name = "power">Power to raise in.</param>
        /// <returns>Returns specified power of 2 in the case if power is in the range of
        ///   [0, 30]. Otherwise returns 0.</returns>
        public static int Pow2(int power)
        {
            return ((power >= 0) && (power <= 30)) ? (1 << power) : 0;
        }

        /// <summary>
        ///   Checks if the specified integer is power of 2.
        /// </summary>
        /// <param name = "x">Integer number to check.</param>
        /// <returns>Returns <b>true</b> if the specified number is power of 2.
        ///   Otherwise returns <b>false</b>.</returns>
        public static bool IsPowerOf2(int x)
        {
            return (x & (x - 1)) == 0;
        }

        /// <summary>
        ///   Get base of binary logarithm.
        /// </summary>
        /// <param name = "x">Source integer number.</param>
        /// <returns>Power of the number (base of binary logarithm).</returns>
        public static int Log2(int x)
        {
            if (x <= 65536)
            {
                if (x <= 256)
                {
                    if (x <= 16)
                    {
                        if (x <= 4)
                        {
                            if (x <= 2)
                            {
                                if (x <= 1)
                                    return 0;
                                return 1;
                            }
                            return 2;
                        }
                        if (x <= 8)
                            return 3;
                        return 4;
                    }
                    if (x <= 64)
                    {
                        if (x <= 32)
                            return 5;
                        return 6;
                    }
                    if (x <= 128)
                        return 7;
                    return 8;
                }
                if (x <= 4096)
                {
                    if (x <= 1024)
                    {
                        if (x <= 512)
                            return 9;
                        return 10;
                    }
                    if (x <= 2048)
                        return 11;
                    return 12;
                }
                if (x <= 16384)
                {
                    if (x <= 8192)
                        return 13;
                    return 14;
                }
                if (x <= 32768)
                    return 15;
                return 16;
            }

            if (x <= 16777216)
            {
                if (x <= 1048576)
                {
                    if (x <= 262144)
                    {
                        if (x <= 131072)
                            return 17;
                        return 18;
                    }
                    if (x <= 524288)
                        return 19;
                    return 20;
                }
                if (x <= 4194304)
                {
                    if (x <= 2097152)
                        return 21;
                    return 22;
                }
                if (x <= 8388608)
                    return 23;
                return 24;
            }
            if (x <= 268435456)
            {
                if (x <= 67108864)
                {
                    if (x <= 33554432)
                        return 25;
                    return 26;
                }
                if (x <= 134217728)
                    return 27;
                return 28;
            }
            if (x <= 1073741824)
            {
                if (x <= 536870912)
                    return 29;
                return 30;
            }
            return 31;
        }
    }
}