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// Copyright © 2006-2010 Travis Robinson. All rights reserved.
//
// website: http://sourceforge.net/projects/libusbdotnet
// e-mail: libusbdotnet@gmail.com
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. or
// visit www.gnu.org.
//
//
using System;
using System.Runtime.InteropServices;
using System.Threading;
namespace LibUsbDotNet.Internal
{
internal class SafeOverlapped : IDisposable
{
// Find the structural starting positions in the NativeOverlapped structure.
private static readonly int FieldOffsetEventHandle = Marshal.OffsetOf(typeof (NativeOverlapped), "EventHandle").ToInt32();
private static readonly int FieldOffsetInternalHigh = Marshal.OffsetOf(typeof (NativeOverlapped), "InternalHigh").ToInt32();
private static readonly int FieldOffsetInternalLow = Marshal.OffsetOf(typeof (NativeOverlapped), "InternalLow").ToInt32();
private static readonly int FieldOffsetOffsetHigh = Marshal.OffsetOf(typeof (NativeOverlapped), "OffsetHigh").ToInt32();
private static readonly int FieldOffsetOffsetLow = Marshal.OffsetOf(typeof (NativeOverlapped), "OffsetLow").ToInt32();
private IntPtr mPtrOverlapped = IntPtr.Zero;
public SafeOverlapped()
{
// Globally allocated the memory for the overlapped structure
mPtrOverlapped = Marshal.AllocHGlobal(Marshal.SizeOf(typeof (NativeOverlapped)));
}
public IntPtr InternalLow
{
get { return Marshal.ReadIntPtr(mPtrOverlapped, FieldOffsetInternalLow); }
set { Marshal.WriteIntPtr(mPtrOverlapped, FieldOffsetInternalLow, value); }
}
public IntPtr InternalHigh
{
get { return Marshal.ReadIntPtr(mPtrOverlapped, FieldOffsetInternalHigh); }
set { Marshal.WriteIntPtr(mPtrOverlapped, FieldOffsetInternalHigh, value); }
}
public int OffsetLow
{
get { return Marshal.ReadInt32(mPtrOverlapped, FieldOffsetOffsetLow); }
set { Marshal.WriteInt32(mPtrOverlapped, FieldOffsetOffsetLow, value); }
}
public int OffsetHigh
{
get { return Marshal.ReadInt32(mPtrOverlapped, FieldOffsetOffsetHigh); }
set { Marshal.WriteInt32(mPtrOverlapped, FieldOffsetOffsetHigh, value); }
}
/// <summary>
/// The overlapped event wait hande.
/// </summary>
public IntPtr EventHandle
{
get { return Marshal.ReadIntPtr(mPtrOverlapped, FieldOffsetEventHandle); }
set { Marshal.WriteIntPtr(mPtrOverlapped, FieldOffsetEventHandle, value); }
}
/// <summary>
/// Pass this into the DeviceIoControl and GetOverlappedResult APIs
/// </summary>
public IntPtr GlobalOverlapped
{
get { return mPtrOverlapped; }
}
#region IDisposable Members
public void Dispose()
{
if (mPtrOverlapped != IntPtr.Zero)
{
Marshal.FreeHGlobal(mPtrOverlapped);
mPtrOverlapped = IntPtr.Zero;
}
}
#endregion
/// <summary>
/// Set the overlapped wait handle and clear out the rest of the structure.
/// </summary>
/// <param name="hEventOverlapped"></param>
public void ClearAndSetEvent(IntPtr hEventOverlapped)
{
EventHandle = hEventOverlapped;
InternalLow = IntPtr.Zero;
InternalHigh = IntPtr.Zero;
OffsetLow = 0;
OffsetHigh = 0;
}
// Clean up the globally allocated memory.
~SafeOverlapped() { Dispose(); }
}
}
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