diff --git a/test/source.cs b/test/source.cs
index e69de29..b2aad3b 100644
--- a/test/source.cs
+++ b/test/source.cs
@@ -0,0 +1,259 @@
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.IO.Compression;
+using System.Runtime.InteropServices;
+using System.Windows.Forms;
+using Microsoft.Win32;
+using Shadowsocks.Controller;
+
+namespace Shadowsocks.Util
+{
+    public struct BandwidthScaleInfo
+    {
+        public float value;
+        public string unitName;
+        public long unit;
+
+        public BandwidthScaleInfo(float value, string unitName, long unit)
+        {
+            this.value = value;
+            this.unitName = unitName;
+            this.unit = unit;
+        }
+    }
+
+    public static class Utils
+    {
+        private static string _tempPath = null;
+
+        // return path to store temporary files
+        public static string GetTempPath()
+        {
+            if (_tempPath == null)
+            {
+                try
+                {
+                    Directory.CreateDirectory(Path.Combine(Application.StartupPath, "ss_win_temp"));
+                    // don't use "/", it will fail when we call explorer /select xxx/ss_win_temp\xxx.log
+                    _tempPath = Path.Combine(Application.StartupPath, "ss_win_temp");
+                }
+                catch (Exception e)
+                {
+                    Logging.Error(e);
+                    throw;
+                }
+            }
+            return _tempPath;
+        }
+
+        // return a full path with filename combined which pointed to the temporary directory
+        public static string GetTempPath(string filename)
+        {
+            return Path.Combine(GetTempPath(), filename);
+        }
+
+        public static void ReleaseMemory(bool removePages)
+        {
+            // release any unused pages
+            // making the numbers look good in task manager
+            // this is totally nonsense in programming
+            // but good for those users who care
+            // making them happier with their everyday life
+            // which is part of user experience
+            GC.Collect(GC.MaxGeneration);
+            GC.WaitForPendingFinalizers();
+            if (removePages)
+            {
+                // as some users have pointed out
+                // removing pages from working set will cause some IO
+                // which lowered user experience for another group of users
+                //
+                // so we do 2 more things here to satisfy them:
+                // 1. only remove pages once when configuration is changed
+                // 2. add more comments here to tell users that calling
+                //    this function will not be more frequent than
+                //    IM apps writing chat logs, or web browsers writing cache files
+                //    if they're so concerned about their disk, they should
+                //    uninstall all IM apps and web browsers
+                //
+                // please open an issue if you're worried about anything else in your computer
+                // no matter it's GPU performance, monitor contrast, audio fidelity
+                // or anything else in the task manager
+                // we'll do as much as we can to help you
+                //
+                // just kidding
+                SetProcessWorkingSetSize(Process.GetCurrentProcess().Handle,
+                                         (UIntPtr)0xFFFFFFFF,
+                                         (UIntPtr)0xFFFFFFFF);
+            }
+        }
+
+        public static string UnGzip(byte[] buf)
+        {
+            byte[] buffer = new byte[1024];
+            int n;
+            using (MemoryStream sb = new MemoryStream())
+            {
+                using (GZipStream input = new GZipStream(new MemoryStream(buf),
+                                                         CompressionMode.Decompress,
+                                                         false))
+                {
+                    while ((n = input.Read(buffer, 0, buffer.Length)) > 0)
+                    {
+                        sb.Write(buffer, 0, n);
+                    }
+                }
+                return System.Text.Encoding.UTF8.GetString(sb.ToArray());
+            }
+        }
+
+        public static string FormatBandwidth(long n)
+        {
+            var result = GetBandwidthScale(n);
+            return $"{result.value:0.##}{result.unitName}";
+        }
+
+        public static string FormatBytes(long bytes)
+        {
+            const long K = 1024L;
+            const long M = K * 1024L;
+            const long G = M * 1024L;
+            const long T = G * 1024L;
+            const long P = T * 1024L;
+            const long E = P * 1024L;
+
+            if (bytes >= P * 990)
+                return (bytes / (double)E).ToString("F5") + "EiB";
+            if (bytes >= T * 990)
+                return (bytes / (double)P).ToString("F5") + "PiB";
+            if (bytes >= G * 990)
+                return (bytes / (double)T).ToString("F5") + "TiB";
+            if (bytes >= M * 990)
+            {
+                return (bytes / (double)G).ToString("F4") + "GiB";
+            }
+            if (bytes >= M * 100)
+            {
+                return (bytes / (double)M).ToString("F1") + "MiB";
+            }
+            if (bytes >= M * 10)
+            {
+                return (bytes / (double)M).ToString("F2") + "MiB";
+            }
+            if (bytes >= K * 990)
+            {
+                return (bytes / (double)M).ToString("F3") + "MiB";
+            }
+            if (bytes > K * 2)
+            {
+                return (bytes / (double)K).ToString("F1") + "KiB";
+            }
+            return bytes.ToString() + "B";
+        }
+
+        /// <summary>
+        /// Return scaled bandwidth
+        /// </summary>
+        /// <param name="n">Raw bandwidth</param>
+        /// <returns>
+        /// The BandwidthScaleInfo struct
+        /// </returns>
+        public static BandwidthScaleInfo GetBandwidthScale(long n)
+        {
+            long scale = 1;
+            float f = n;
+            string unit = "B";
+            if (f > 1024)
+            {
+                f = f / 1024;
+                scale <<= 10;
+                unit = "KiB";
+            }
+            if (f > 1024)
+            {
+                f = f / 1024;
+                scale <<= 10;
+                unit = "MiB";
+            }
+            if (f > 1024)
+            {
+                f = f / 1024;
+                scale <<= 10;
+                unit = "GiB";
+            }
+            if (f > 1024)
+            {
+                f = f / 1024;
+                scale <<= 10;
+                unit = "TiB";
+            }
+            return new BandwidthScaleInfo(f, unit, scale);
+        }
+
+        public static RegistryKey OpenRegKey(string name, bool writable, RegistryHive hive = RegistryHive.CurrentUser)
+        {
+            // we are building x86 binary for both x86 and x64, which will
+            // cause problem when opening registry key
+            // detect operating system instead of CPU
+            if (name.IsNullOrEmpty()) throw new ArgumentException(nameof(name));
+            try
+            {
+                RegistryKey userKey = RegistryKey.OpenBaseKey(hive,
+                        Environment.Is64BitOperatingSystem ? RegistryView.Registry64 : RegistryView.Registry32)
+                    .OpenSubKey(name, writable);
+                return userKey;
+            }
+            catch (ArgumentException ae)
+            {
+                MessageBox.Show("OpenRegKey: " + ae.ToString());
+                return null;
+            }
+            catch (Exception e)
+            {
+                Logging.LogUsefulException(e);
+                return null;
+            }
+        }
+
+        public static bool IsWinVistaOrHigher()
+        {
+            return Environment.OSVersion.Version.Major > 5;
+        }
+
+        [DllImport("kernel32.dll")]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        private static extern bool SetProcessWorkingSetSize(IntPtr process,
+            UIntPtr minimumWorkingSetSize, UIntPtr maximumWorkingSetSize);
+
+
+        // See: https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx
+        public static bool IsSupportedRuntimeVersion()
+        {
+            /*
+             * +-----------------------------------------------------------------+----------------------------+
+             * | Version                                                         | Value of the Release DWORD |
+             * +-----------------------------------------------------------------+----------------------------+
+             * | .NET Framework 4.6.2 installed on Windows 10 Anniversary Update | 394802                     |
+             * | .NET Framework 4.6.2 installed on all other Windows OS versions | 394806                     |
+             * +-----------------------------------------------------------------+----------------------------+
+             */
+            const int minSupportedRelease = 394802;
+
+            const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";
+            using (var ndpKey = OpenRegKey(subkey, false, RegistryHive.LocalMachine))
+            {
+                if (ndpKey?.GetValue("Release") != null)
+                {
+                    var releaseKey = (int)ndpKey.GetValue("Release");
+
+                    if (releaseKey >= minSupportedRelease)
+                    {
+                        return true;
+                    }
+                }
+            }
+            return false;
+        }
+    }
+}
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