public override IAsyncResult BeginWrite(byte[] array, int offset, int numBytes, AsyncCallback userCallback, Object stateObject)
{
if (array == null)
{
throw new ArgumentNullException("array");
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException("offset", Helper.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
}
if (numBytes < 0)
{
throw new ArgumentOutOfRangeException("numBytes", Helper.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
}
if (array.Length - offset < numBytes)
{
throw new ArgumentException(Helper.GetResourceString("Argument_InvalidOffLen"));
}
if (!CanWrite)
{
__Error.WriteNotSupported();
}
Debug.Assert((_readPos == 0 && _readLen == 0 && _writePos >= 0) || (_writePos == 0 && _readPos <= _readLen), "We're either reading or writing, but not both.");
if (_writePos == 0)
{
if (_readPos < _readLen)
{
FlushRead();
}
_readPos = 0;
_readLen = 0;
}
int n = bufferSize - _writePos;
if (numBytes <= n)
{
if (_buffer == null)
{
_buffer = new byte[bufferSize];
}
Buffer.BlockCopy(array, offset, _buffer, _writePos, numBytes);
_writePos += numBytes;
return(BufferedStreamAsyncResult.Complete(numBytes, userCallback, stateObject, true));
}
if (_writePos > 0)
{
FlushWrite(false);
}
return(BeginWriteCore(array, offset, numBytes, userCallback, stateObject));
}
public unsafe override void EndWrite(IAsyncResult asyncResult)
{
if (asyncResult == null)
{
throw new ArgumentNullException("asyncResult");
}
BufferedStreamAsyncResult bsar = asyncResult as BufferedStreamAsyncResult;
if (bsar == null)
{
EndWriteCore(asyncResult);
}
}
internal static IAsyncResult Complete(int numBufferedBytes, AsyncCallback userCallback, Object userStateObject, bool isWrite)
{
// Fake async
BufferedStreamAsyncResult asyncResult = new BufferedStreamAsyncResult();
asyncResult._numBytes = numBufferedBytes;
asyncResult._userCallback = userCallback;
asyncResult._userStateObject = userStateObject;
asyncResult._isWrite = isWrite;
if (userCallback != null)
{
userCallback(asyncResult);
}
return(asyncResult);
}
public unsafe override int EndRead(IAsyncResult asyncResult)
{
if (asyncResult == null)
{
throw new ArgumentNullException("asyncResult");
}
BufferedStreamAsyncResult bsar = asyncResult as BufferedStreamAsyncResult;
if (bsar != null)
{
if (bsar._isWrite)
{
__Error.WrongAsyncResult();
}
return(bsar._numBytes);
}
else
{
return(EndReadCore(asyncResult));
}
}
internal static IAsyncResult Complete(int numBufferedBytes, AsyncCallback userCallback, Object userStateObject, bool isWrite)
{
// Fake async
BufferedStreamAsyncResult asyncResult = new BufferedStreamAsyncResult();
asyncResult._numBytes = numBufferedBytes;
asyncResult._userCallback = userCallback;
asyncResult._userStateObject = userStateObject;
asyncResult._isWrite = isWrite;
if (userCallback != null) {
userCallback(asyncResult);
}
return asyncResult;
}
public override IAsyncResult BeginRead(byte[] array, int offset, int numBytes, AsyncCallback userCallback, Object stateObject)
{
if (array == null)
{
throw new ArgumentNullException("array");
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException("offset", Helper.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
}
if (numBytes < 0)
{
throw new ArgumentOutOfRangeException("numBytes", Helper.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
}
if (array.Length - offset < numBytes)
{
throw new ArgumentException(Helper.GetResourceString("Argument_InvalidOffLen"));
}
if (!CanRead)
{
__Error.ReadNotSupported();
}
Debug.Assert((_readPos == 0 && _readLen == 0 && _writePos >= 0) || (_writePos == 0 && _readPos <= _readLen), "We're either reading or writing, but not both.");
if (_writePos > 0)
{
FlushWrite(false);
}
if (_readPos == _readLen)
{
// I can't see how to handle buffering of async requests when
// filling the buffer asynchronously, without a lot of complexity.
// The problems I see are issuing an async read, we do an async
// read to fill the buffer, then someone issues another read
// (either synchronously or asynchronously) before the first one
// returns. This would involve some sort of complex buffer locking
// that we probably don't want to get into, at least not in V1.
// If we did a sync read to fill the buffer, we could avoid the
// problem, and any async read less than 64K gets turned into a
// synchronous read by NT anyways... --
if (numBytes < bufferSize)
{
if (_buffer == null)
{
_buffer = new byte[bufferSize];
}
IAsyncResult bufferRead = BeginReadCore(_buffer, 0, bufferSize, null, null, 0);
_readLen = EndRead(bufferRead);
int n = _readLen;
if (n > numBytes)
{
n = numBytes;
}
Buffer.BlockCopy(_buffer, 0, array, offset, n);
_readPos = n;
// Fake async
return(BufferedStreamAsyncResult.Complete(n, userCallback, stateObject, false));
}
// Here we're making our position pointer inconsistent
// with our read buffer. Throw away the read buffer's contents.
_readPos = 0;
_readLen = 0;
return(BeginReadCore(array, offset, numBytes, userCallback, stateObject, 0));
}
else
{
int n = _readLen - _readPos;
if (n > numBytes)
{
n = numBytes;
}
Buffer.BlockCopy(_buffer, _readPos, array, offset, n);
_readPos += n;
if (n >= numBytes)
{
return(BufferedStreamAsyncResult.Complete(n, userCallback, stateObject, false));
}
// For streams with no clear EOF like serial ports or pipes
// we cannot read more data without causing an app to block
// incorrectly. Pipes don't go down this path
// though. This code needs to be fixed.
// Throw away read buffer.
_readPos = 0;
_readLen = 0;
// WARNING: all state on asyncResult objects must be set before
// we call ReadFile in BeginReadCore, since the OS can run our
// callback & the user's callback before ReadFile returns.
return(BeginReadCore(array, offset + n, numBytes - n, userCallback, stateObject, n));
}
}
