C# Stream.BeginWrite方法代码示例

 private static void WriteToStreamAsync(Stream s)
 {
     var t = Task.Factory.FromAsync(
         (callback, state) => s.BeginWrite(new byte[] { 1, 2, 3 }, 0, 3, callback, state),
         (ar) => s.EndWrite(ar),
         null);
     t.Wait();
 }

        protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
        {
            Contract.Assert(stream != null);

            // Serialize header
            byte[] header = SerializeHeader();

            TaskCompletionSource<object> writeTask = new TaskCompletionSource<object>();
            try
            {
                // We don't use TaskFactory.FromAsync as it generates an FxCop CA908 error
                Tuple<HttpMessageContent, Stream, TaskCompletionSource<object>> state =
                    new Tuple<HttpMessageContent, Stream, TaskCompletionSource<object>>(this, stream, writeTask);
                IAsyncResult result = stream.BeginWrite(header, 0, header.Length, _onWriteComplete, state);
                if (result.CompletedSynchronously)
                {
                    WriteComplete(result, this, stream, writeTask);
                }
            }
            catch (Exception e)
            {
                writeTask.TrySetException(e);
            }

            return writeTask.Task;
        }

        public static WaitHandle AsyncCopy(this Stream src, Stream dst)
        {
            var evt = new ManualResetEvent(false);
            var buffer = new byte[BUFFER_SIZE];

            AsyncCallback cbk = null;
            cbk = (asyncReadResult) =>
            {
                int bytesRead = src.EndRead(asyncReadResult);
                if (bytesRead > 0)
                {
                    //Console.Write("r");
                    dst.BeginWrite(buffer, 0, bytesRead,
                        (asyncWriteResult) =>
                        {
                            //Console.Write("w");
                            dst.EndWrite(asyncWriteResult);
                            src.BeginRead(buffer, 0, buffer.Length, cbk, null);
                        }, null);
                }
                else
                {
                    Console.WriteLine();
                    dst.Flush();
                    dst.Position = 0;
                    evt.Set();
                }
            };
            src.BeginRead(buffer, 0, buffer.Length, cbk, buffer);
            return evt;
        }

        /// <summary>
        /// Pipes data from one stream to another
        /// </summary>
        /// <param name="input">Stream to read from</param>
        /// <param name="output">Stream to write to</param>
        /// <param name="MaxBufferSize">Size of buffer to use</param>
        /// <returns>Number of bytes piped</returns>
        public static int Pipe(Stream input, Stream output, int MaxBufferSize)
        {
            //Internal buffer are two buffers, each half of allowed buffer size, aligned to 1kb blocks
            int bufferSize = (MaxBufferSize / 2) & ~1023;
            if (bufferSize <= 0) throw new Exception("Specified buffer size to small");

            byte[][] buffer = new byte[2][];
            buffer[0] = new byte[bufferSize];
            buffer[1] = new byte[bufferSize];
            int currentBuffer = 0;

            int r, total=0;
            IAsyncResult asyncRead,asyncWrite;

            //Read first block
            r = input.Read(buffer[currentBuffer], 0, bufferSize);

            //Continue while we're getting data
            while (r > 0)
            {
                //read and write simultaneously
                asyncWrite = output.BeginWrite(buffer[currentBuffer], 0, r, null, null);
                asyncRead = input.BeginRead(buffer[1-currentBuffer], 0, bufferSize, null, null);
                //Wait for both
                output.EndWrite(asyncWrite);
                r = input.EndRead(asyncRead);
                //Switch buffers
                currentBuffer = 1 - currentBuffer;
                //Count bytes
                total += r;
            }

            //Return number of bytes piped
            return total;
        }

        // http://stackoverflow.com/questions/1540658/net-asynchronous-stream-read-write
        public static void CopyTo(this Stream input, Stream output, int bufferSize)
        {
            if (!input.CanRead) throw new InvalidOperationException("input must be open for reading");
            if (!output.CanWrite) throw new InvalidOperationException("output must be open for writing");

            byte[][] buf = { new byte[bufferSize], new byte[bufferSize] };
            int[] bufl = { 0, 0 };
            int bufno = 0;

            IAsyncResult read = input.BeginRead(buf[bufno], 0, buf[bufno].Length, null, null);
            IAsyncResult write = null;

            while (true) {

                // wait for the read operation to complete
                read.AsyncWaitHandle.WaitOne();
                bufl[bufno] = input.EndRead(read);

                // if zero bytes read, the copy is complete
                if (bufl[bufno] == 0) {
                    break;
                }

                // wait for the in-flight write operation, if one exists, to complete
                // the only time one won't exist is after the very first read operation completes
                if (write != null) {
                    write.AsyncWaitHandle.WaitOne();
                    output.EndWrite(write);
                }

                // start the new write operation
                write = output.BeginWrite(buf[bufno], 0, bufl[bufno], null, null);

                // toggle the current, in-use buffer
                // and start the read operation on the new buffer
                bufno = (bufno == 0 ? 1 : 0);
                read = input.BeginRead(buf[bufno], 0, buf[bufno].Length, null, null);

            }

            // wait for the final in-flight write operation, if one exists, to complete
            // the only time one won't exist is if the input stream is empty.
            if (write != null) {
                write.AsyncWaitHandle.WaitOne();
                output.EndWrite(write);
            }

            output.Flush();

            // return to the caller ;
            return;
        }

        private static IEnumerable<CompletionPort> CreateFixedVhdFileAtAsync(AsyncMachine machine, Stream destination, long virtualSize)
        {
            var footer = VhdFooterFactory.CreateFixedDiskFooter(virtualSize);
            var serializer = new VhdFooterSerializer(footer);
            var buffer = serializer.ToByteArray();
            destination.SetLength(virtualSize + VhdConstants.VHD_FOOTER_SIZE);
            destination.Seek(-VhdConstants.VHD_FOOTER_SIZE, SeekOrigin.End);

            destination.BeginWrite(buffer, 0, buffer.Length, machine.CompletionCallback, null);
            yield return CompletionPort.SingleOperation;
            destination.EndWrite(machine.CompletionResult);
            destination.Flush();
        }

        /// <summary>
        /// Copies the contents between two <see cref="Stream"/> instances in an async fashion.
        /// </summary>
        /// <param name="source">The source stream to copy from.</param>
        /// <param name="destination">The destination stream to copy to.</param>
        /// <param name="onComplete">Delegate that should be invoked when the operation has completed. Will pass the source, destination and exception (if one was thrown) to the function. Can pass in <see langword="null" />.</param>
        public static void CopyTo(this Stream source, Stream destination, Action<Stream, Stream, Exception> onComplete)
        {
            var buffer =
                new byte[BufferSize];

            Action<Exception> done = e =>
            {
                if (onComplete != null)
                {
                    onComplete.Invoke(source, destination, e);
                }
            };

            AsyncCallback rc = null;

            rc = readResult =>
            {
                try
                {
                    var read =
                        source.EndRead(readResult);

                    if (read <= 0)
                    {
                        done.Invoke(null);
                        return;
                    }

                    destination.BeginWrite(buffer, 0, read, writeResult =>
                    {
                        try
                        {
                            destination.EndWrite(writeResult);
                            source.BeginRead(buffer, 0, buffer.Length, rc, null);
                        }
                        catch (Exception ex)
                        {
                            done.Invoke(ex);
                        }

                    }, null);
                }
                catch (Exception ex)
                {
                    done.Invoke(ex);
                }
            };

            source.BeginRead(buffer, 0, buffer.Length, rc, null);
        }

        protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
        {
            var tcs = new TaskCompletionSource<object>();
            _body.Invoke(
                (data, callback) =>
                {
                    if (data.Count == 0)
                    {
                        stream.Flush();
                    }
                    else if (callback == null)
                    {
                        stream.Write(data.Array, data.Offset, data.Count);
                    }
                    else
                    {
                        var sr = stream.BeginWrite(data.Array, data.Offset, data.Count, ar =>
                        {
                            if (!ar.CompletedSynchronously)
                            {
                                try { stream.EndWrite(ar); }
                                catch { }
                                try { callback.Invoke(); }
                                catch { }
                            }
                        }, null);

                        if (!sr.CompletedSynchronously)
                        {
                            return true;
                        }
                        stream.EndWrite(sr);
                        callback.Invoke();
                    }
                    return false;
                },
                ex =>
                {
                    if (ex == null)
                    {
                        tcs.TrySetResult(null);
                    }
                    else
                    {
                        tcs.TrySetException(ex);
                    }
                },
                _cancellationToken);
            return tcs.Task;
        }

        public Task Start(Stream stream)
        {
            TaskCompletionSource<object> completed = new TaskCompletionSource<object>();
            var bytes = encoding.GetBytes(text);
            stream.BeginWrite(bytes, 0, bytes.Length,
                async =>
                {
                    try
                    {
                        stream.EndWrite(async);
                        completed.TrySetResult(null);
                    }
                    catch (Exception ex)
                    {
                        completed.TrySetException(ex);
                    }
                },
                null);

            return completed.Task;
        }

      private static IEnumerator<Int32> CopyStream(AsyncEnumerator<Int64> ae, Stream source, Stream destination, Int32 bufferSize, Action<Int64> reportProgress) {
         Byte[] buffer = new Byte[bufferSize];
         Int64 totalBytesRead = 0;
         while (true) {
            ae.SetOperationTag("Reading from source stream");
            // Read whichever is smaller (number of bytes left to read OR the buffer size)
            source.BeginRead(buffer, 0, buffer.Length, ae.End(), null);
            yield return 1;
            Int32 bytesReadThisTime = source.EndRead(ae.DequeueAsyncResult());
            totalBytesRead += bytesReadThisTime;

            ae.SetOperationTag("Writing to destination stream");
            destination.BeginWrite(buffer, 0, bytesReadThisTime, ae.End(), null);
            yield return 1;
            destination.EndWrite(ae.DequeueAsyncResult());

            if (reportProgress != null) reportProgress(totalBytesRead);
            if (bytesReadThisTime < buffer.Length) break;
         }
         ae.Result = totalBytesRead;
      }

        static IEnumerable<Task> CopyStream(Stream input, Stream output)
        {
            var buffer = new byte[0x2000];

            while (true)
            {
                // Create task to read from the input stream
                var read = Task<int>.Factory.FromAsync((buf, offset, count, callback, state) =>
                                                           {
                                                               Console.WriteLine("Issuing BeginRead");
                                                               return input.BeginRead(buf, offset, count, callback, state);
                                                           },
                                                           ar =>
                                                               {
                                                                   Console.WriteLine("Read completed");
                                                                   return input.EndRead(ar);
                                                               },
                                                               buffer, 0, buffer.Length, null);

                yield return read;

                // If we read no data, return
                if (read.Result == 0) break;

                // Create task to write to the output stream
                yield return Task.Factory.FromAsync((buf, offset, count, callback, state) =>
                                                           {
                                                               Console.WriteLine("Issuing BeginWrite");
                                                               return output.BeginWrite(buf, offset, count, callback, state);
                                                           },
                                                           ar =>
                                                               {
                                                                   Console.WriteLine("Write completed");
                                                                   output.EndWrite(ar);
                                                               }, buffer, 0, read.Result, null);
            }
        }

 public static void CopyTo(this Stream source, Stream destination, int bufferSize)
 {
     long ts = DateTime.Now.Ticks;
     long cbTotal = 0L;
     byte[] read_buffer = new byte[bufferSize];
     int cb = source.Read(read_buffer, 0, read_buffer.Length);
     AutoResetEvent writeLock = new AutoResetEvent(false);
     while (cb > 0)
     {
         cbTotal += cb;
         try
         {
             byte[] write_buffer = read_buffer;
             destination.BeginWrite(write_buffer, 0, cb, (AsyncCallback)delegate(IAsyncResult ar)
             {
                 try
                 {
                     destination.EndWrite(ar);
                 }
                 finally
                 {
                     writeLock.Set();
                 }
             }, null);
         }
         catch
         {
             writeLock.Set();
             throw;
         }
         read_buffer = new byte[bufferSize];
         cb = source.Read(read_buffer, 0, read_buffer.Length);
         writeLock.WaitOne();
     }
     ts = DateTime.Now.Ticks - ts;
 }

        public ProgressWriteAsyncResult(Stream innerStream, ProgressStream progressStream, byte[] buffer, int offset, int count, AsyncCallback callback, object state)
            : base(callback, state)
        {
            Contract.Assert(innerStream != null);
            Contract.Assert(progressStream != null);
            Contract.Assert(buffer != null);

            _innerStream = innerStream;
            _progressStream = progressStream;
            _count = count;

            try
            {
                IAsyncResult result = innerStream.BeginWrite(buffer, offset, count, _writeCompletedCallback, this);
                if (result.CompletedSynchronously)
                {
                    WriteCompleted(result);
                }
            }
            catch (Exception e)
            {
                Complete(true, e);
            }
        }

        public static void StreamWriteAsync(
            Stream stream,
            byte[] buffer,
            int offset,
            int count,
            SynchronizationContextWrapper syncContext,
            Action<int, Exception> callback)
        {
            Exception error = null;
            int length = 0;

            try
            {
                stream.BeginWrite(buffer, offset, count,
                    delegate(IAsyncResult ar)
                    {
                        try
                        {
                            stream.EndWrite(ar);
                            stream.Flush();
                            length = count;
                        }
                        catch (Exception e)
                        {
                            error = e;
                        }

                        callback(length, error);
                    },
                    null);
            }
            catch (Exception e)
            {
                error = e;
                callback(length, error);
            }
        } 

 public Task WriteToStreamAsync(Stream stream)
 {
     return Task.Factory.FromAsync((Func<AsyncCallback, object, IAsyncResult>) ((callback, state) => stream.BeginWrite(this.buffer, 0, this.storedCount, callback, state)), new Action<IAsyncResult>(stream.EndWrite), null);
 }