using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.IO.Compression;
using System.Runtime.InteropServices;
using System.Text;

namespace Shadowsocks.Util
{
    public class Utils
    {
        public static void ReleaseMemory()
        {
            // 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();
            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());
            }
        }

        [DllImport("kernel32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool SetProcessWorkingSetSize(IntPtr process,
            UIntPtr minimumWorkingSetSize, UIntPtr maximumWorkingSetSize);
    }
}