public ulong SeekU(ulong offset, SeekOrigin origin)
{
ulong n = 0;
if (!DeviceIO.SetFilePointerEx(this.fileHandle, offset, out n, (uint)origin))
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
return(n);
}
public override void Close()
{
if (this.fileHandle != null)
{
DeviceIO.CloseHandle(this.fileHandle);
this.fileHandle.SetHandleAsInvalid();
this.fileHandle = null;
}
base.Close();
}
public unsafe void Write(byte[] buffer, uint offset, uint count)
{
uint n = 0;
fixed(byte *p = buffer)
{
if (!DeviceIO.WriteFile(this.fileHandle, p + offset, count, &n, IntPtr.Zero))
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
}
}
private SafeFileHandle openFile(string id, FileAccess desiredAccess)
{
uint access;
switch (desiredAccess)
{
case FileAccess.Read:
access = DeviceIO.GENERIC_READ;
break;
case FileAccess.Write:
access = DeviceIO.GENERIC_WRITE;
break;
case FileAccess.ReadWrite:
access = DeviceIO.GENERIC_READ | DeviceIO.GENERIC_WRITE;
break;
default:
access = DeviceIO.GENERIC_READ;
break;
}
SafeFileHandle ptr = DeviceIO.CreateFile(
id,
access,
DeviceIO.FILE_SHARE_WRITE,
IntPtr.Zero,
DeviceIO.OPEN_EXISTING,
DeviceIO.FILE_FLAG_WRITE_THROUGH,
IntPtr.Zero);
if (ptr.IsInvalid)
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
return(ptr);
}