// (c) 2006 Richard Grimes
// www.grimes.demon.co.uk

using System;
using System.Security;
using System.Reflection;
using System.Runtime.InteropServices;

[assembly: AssemblyKeyFile("key.snk")]
[assembly: AssemblyVersion("1.0.0.0")]

[assembly: AllowPartiallyTrustedCallers]

public class DiskInfo
{
   [DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]
   static extern bool GetDiskFreeSpaceEx(
      string drive, out long freeBytesForUser, 
      out long totalBytes, out long freeBytes);
   [DllImport("kernel32")]
   static extern int SetErrorMode(int newMode);

   public static long AvailableFreeSpace(string disk)
   {
      int errorMode = SetErrorMode(1);
      long freeBytes, totalBytes, totalFreeBytes;
      try
      {
         if (!GetDiskFreeSpaceEx(disk, out freeBytes, out totalBytes, out totalFreeBytes))
         {
            throw new ArgumentException(
               String.Format("cannot get free space for {0} 0x{1:x8}", 
                  disk, Marshal.GetLastWin32Error()));
         }
      }
      finally
      {
         SetErrorMode(errorMode);
      }
      return freeBytes;
   }
}