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// Copyright © 2006-2009 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.Threading;
using LibUsbDotNet.Main;
using Microsoft.Win32.SafeHandles;
namespace LibUsbDotNet.Internal
{
public abstract class TransferContextBase : IDisposable
{
private readonly UsbEndpointBase mEndpointBase;
private IntPtr mBuffer;
private int mCurrentOffset;
private int mCurrentRemaining;
private int mCurrentTransmitted;
private int mFailRetries;
protected int mOriginalCount;
protected int mOriginalOffset;
private PinnedHandle mPinnedHandle;
protected int mTimeout;
protected bool mHasWaitBeenCalled = true;
protected ManualResetEvent mTransferCancelEvent = new ManualResetEvent(false);
protected internal ManualResetEvent mTransferCompleteEvent = new ManualResetEvent(true);
protected TransferContextBase(UsbEndpointBase endpointBase) { mEndpointBase = endpointBase; }
public UsbEndpointBase EndpointBase
{
get { return mEndpointBase; }
}
protected int RequestCount
{
get { return (mCurrentRemaining > UsbEndpointBase.MaxReadWrite ? UsbEndpointBase.MaxReadWrite : mCurrentRemaining); }
}
protected int FailRetries
{
get { return mFailRetries; }
}
protected IntPtr NextBufPtr
{
get { return new IntPtr(mBuffer.ToInt64() + mCurrentOffset); }
}
public bool IsCancelled
{
get { return mTransferCancelEvent.WaitOne(0, UsbConstants.EXIT_CONTEXT); }
}
public bool IsComplete
{
get { return mTransferCompleteEvent.WaitOne(0, UsbConstants.EXIT_CONTEXT); }
}
public SafeWaitHandle CancelWaitHandle
{
get { return mTransferCancelEvent.SafeWaitHandle; }
}
public SafeWaitHandle CompleteWaitHandle
{
get { return mTransferCompleteEvent.SafeWaitHandle; }
}
#region IDisposable Members
public virtual void Dispose()
{
if (!IsCancelled) Cancel();
int dummy;
if (!mHasWaitBeenCalled) Wait(out dummy);
}
#endregion
public virtual ErrorCode Cancel()
{
mTransferCancelEvent.Set();
return ErrorCode.Success;
}
public abstract ErrorCode Submit();
public abstract ErrorCode Wait(out int transferredCount);
public virtual void Fill(object buffer, int offset, int count, int timeout)
{
if (mPinnedHandle != null) mPinnedHandle.Dispose();
mPinnedHandle = new PinnedHandle(buffer);
Fill(mPinnedHandle.Handle, offset, count, timeout);
}
public virtual void Fill(IntPtr buffer, int offset, int count, int timeout)
{
mBuffer = buffer;
mOriginalOffset = offset;
mOriginalCount = count;
mTimeout = timeout;
Reset();
}
internal static ErrorCode SyncTransfer(TransferContextBase transferContext,
IntPtr buffer,
int offset,
int length,
int timeout,
out int transferLength)
{
if (ReferenceEquals(transferContext, null)) throw new NullReferenceException("Invalid transfer context.");
if (offset < 0) throw new ArgumentException("must be >=0", "offset");
lock (transferContext)
{
transferLength = 0;
int transferred;
ErrorCode ec;
transferContext.Fill(buffer, offset, length, timeout);
while (true)
{
ec = transferContext.Submit();
if (ec == ErrorCode.IoEndpointGlobalCancelRedo) continue;
if (ec != ErrorCode.Success) return ec;
ec = transferContext.Wait(out transferred);
if (ec == ErrorCode.IoEndpointGlobalCancelRedo) continue;
if (ec != ErrorCode.Success) return ec;
transferLength += transferred;
if ((ec != ErrorCode.None || transferred != UsbEndpointBase.MaxReadWrite) ||
!transferContext.IncrementTransfer(transferred))
break;
}
return ec;
}
}
public bool IncrementTransfer(int amount)
{
mCurrentTransmitted += amount;
mCurrentOffset += amount;
mCurrentRemaining -= amount;
if (mCurrentRemaining <= 0) return false;
return true;
}
protected void IncFailRetries() { mFailRetries++; }
public void Reset()
{
mCurrentOffset = mOriginalOffset;
mCurrentRemaining = mOriginalCount;
mCurrentTransmitted = 0;
mFailRetries = 0;
mTransferCancelEvent.Reset();
}
}
}
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