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BufferedStream Class

Definition

Adds a buffering layer to read and write operations on another stream. This class cannot be inherited.

C#
public sealed class BufferedStream : System.IO.Stream
C#
[System.Runtime.InteropServices.ComVisible(true)]
public sealed class BufferedStream : System.IO.Stream
Inheritance
BufferedStream
Inheritance
Attributes

Examples

The following code examples show how to use the BufferedStream class over the NetworkStream class to increase the performance of certain I/O operations. Start the server on a remote computer before starting the client. Specify the remote computer name as a command-line argument when starting the client. Vary the dataArraySize and streamBufferSize constants to view their effect on performance.

The first example shows the code that runs on the client, and the second example shows the code that runs on the server.

Example 1: Code that runs on the client

C#
using System;
using System.IO;
using System.Globalization;
using System.Net;
using System.Net.Sockets;

public class Client
{
    const int dataArraySize    =   100;
    const int streamBufferSize =  1000;
    const int numberOfLoops    = 10000;

    static void Main(string[] args)
    {
        // Check that an argument was specified when the
        // program was invoked.
        if(args.Length == 0)
        {
            Console.WriteLine("Error: The name of the host computer" +
                " must be specified when the program is invoked.");
            return;
        }

        string remoteName = args[0];

        // Create the underlying socket and connect to the server.
        Socket clientSocket = new Socket(AddressFamily.InterNetwork,
            SocketType.Stream, ProtocolType.Tcp);

        clientSocket.Connect(new IPEndPoint(
            Dns.Resolve(remoteName).AddressList[0], 1800));

        Console.WriteLine("Client is connected.\n");

        // Create a NetworkStream that owns clientSocket and
        // then create a BufferedStream on top of the NetworkStream.
        // Both streams are disposed when execution exits the
        // using statement.
        using(Stream
            netStream = new NetworkStream(clientSocket, true),
            bufStream =
                  new BufferedStream(netStream, streamBufferSize))
        {
            // Check whether the underlying stream supports seeking.
            Console.WriteLine("NetworkStream {0} seeking.\n",
                bufStream.CanSeek ? "supports" : "does not support");

            // Send and receive data.
            if(bufStream.CanWrite)
            {
                SendData(netStream, bufStream);
            }
            if(bufStream.CanRead)
            {
                ReceiveData(netStream, bufStream);
            }

            // When bufStream is closed, netStream is in turn
            // closed, which in turn shuts down the connection
            // and closes clientSocket.
            Console.WriteLine("\nShutting down the connection.");
            bufStream.Close();
        }
    }

    static void SendData(Stream netStream, Stream bufStream)
    {
        DateTime startTime;
        double networkTime, bufferedTime;

        // Create random data to send to the server.
        byte[] dataToSend = new byte[dataArraySize];
        new Random().NextBytes(dataToSend);

        // Send the data using the NetworkStream.
        Console.WriteLine("Sending data using NetworkStream.");
        startTime = DateTime.Now;
        for(int i = 0; i < numberOfLoops; i++)
        {
            netStream.Write(dataToSend, 0, dataToSend.Length);
        }
        networkTime = (DateTime.Now - startTime).TotalSeconds;
        Console.WriteLine("{0} bytes sent in {1} seconds.\n",
            numberOfLoops * dataToSend.Length,
            networkTime.ToString("F1"));

        // Send the data using the BufferedStream.
        Console.WriteLine("Sending data using BufferedStream.");
        startTime = DateTime.Now;
        for(int i = 0; i < numberOfLoops; i++)
        {
            bufStream.Write(dataToSend, 0, dataToSend.Length);
        }
        bufStream.Flush();
        bufferedTime = (DateTime.Now - startTime).TotalSeconds;
        Console.WriteLine("{0} bytes sent in {1} seconds.\n",
            numberOfLoops * dataToSend.Length,
            bufferedTime.ToString("F1"));

        // Print the ratio of write times.
        Console.WriteLine("Sending data using the buffered " +
            "network stream was {0} {1} than using the network " +
            "stream alone.\n",
            (networkTime/bufferedTime).ToString("P0"),
            bufferedTime < networkTime ? "faster" : "slower");
    }

    static void ReceiveData(Stream netStream, Stream bufStream)
    {
        DateTime startTime;
        double networkTime, bufferedTime = 0;
        int bytesReceived = 0;
        byte[] receivedData = new byte[dataArraySize];

        // Receive data using the NetworkStream.
        Console.WriteLine("Receiving data using NetworkStream.");
        startTime = DateTime.Now;
        while(bytesReceived < numberOfLoops * receivedData.Length)
        {
            bytesReceived += netStream.Read(
                receivedData, 0, receivedData.Length);
        }
        networkTime = (DateTime.Now - startTime).TotalSeconds;
        Console.WriteLine("{0} bytes received in {1} seconds.\n",
            bytesReceived.ToString(),
            networkTime.ToString("F1"));

        // Receive data using the BufferedStream.
        Console.WriteLine("Receiving data using BufferedStream.");
        bytesReceived = 0;
        startTime = DateTime.Now;

        int numBytesToRead = receivedData.Length;

        while (numBytesToRead > 0)
        {
            // Read may return anything from 0 to numBytesToRead.
            int n = bufStream.Read(receivedData,0, receivedData.Length);
            // The end of the file is reached.
            if (n == 0)
                break;
            bytesReceived += n;
            numBytesToRead -= n;
        }

        bufferedTime = (DateTime.Now - startTime).TotalSeconds;
        Console.WriteLine("{0} bytes received in {1} seconds.\n",
            bytesReceived.ToString(),
            bufferedTime.ToString("F1"));

        // Print the ratio of read times.
        Console.WriteLine("Receiving data using the buffered network" +
            " stream was {0} {1} than using the network stream alone.",
            (networkTime/bufferedTime).ToString("P0"),
            bufferedTime < networkTime ? "faster" : "slower");
    }
}

Example 2: Code that runs on the server

C#
using System;
using System.Net;
using System.Net.Sockets;

public class Server
{
    static void Main()
    {
        // This is a Windows Sockets 2 error code.
        const int WSAETIMEDOUT = 10060;

        Socket serverSocket;
        int bytesReceived, totalReceived = 0;
        byte[] receivedData = new byte[2000000];

        // Create random data to send to the client.
        byte[] dataToSend = new byte[2000000];
        new Random().NextBytes(dataToSend);

        IPAddress ipAddress =
            Dns.Resolve(Dns.GetHostName()).AddressList[0];

        IPEndPoint ipEndpoint = new IPEndPoint(ipAddress, 1800);

        // Create a socket and listen for incoming connections.
        using(Socket listenSocket = new Socket(
            AddressFamily.InterNetwork, SocketType.Stream,
            ProtocolType.Tcp))
        {
            listenSocket.Bind(ipEndpoint);
            listenSocket.Listen(1);

            // Accept a connection and create a socket to handle it.
            serverSocket = listenSocket.Accept();
            Console.WriteLine("Server is connected.\n");
        }

        try
        {
            // Send data to the client.
            Console.Write("Sending data ... ");
            int bytesSent = serverSocket.Send(
                dataToSend, 0, dataToSend.Length, SocketFlags.None);
            Console.WriteLine("{0} bytes sent.\n",
                bytesSent.ToString());

            // Set the timeout for receiving data to 2 seconds.
            serverSocket.SetSocketOption(SocketOptionLevel.Socket,
                SocketOptionName.ReceiveTimeout, 2000);

            // Receive data from the client.
            Console.Write("Receiving data ... ");
            try
            {
                do
                {
                    bytesReceived = serverSocket.Receive(receivedData,
                        0, receivedData.Length, SocketFlags.None);
                    totalReceived += bytesReceived;
                }
                while(bytesReceived != 0);
            }
            catch(SocketException e)
            {
                if(e.ErrorCode == WSAETIMEDOUT)
                {
                    // Data was not received within the given time.
                    // Assume that the transmission has ended.
                }
                else
                {
                    Console.WriteLine("{0}: {1}\n",
                        e.GetType().Name, e.Message);
                }
            }
            finally
            {
                Console.WriteLine("{0} bytes received.\n",
                    totalReceived.ToString());
            }
        }
        finally
        {
            serverSocket.Shutdown(SocketShutdown.Both);
            Console.WriteLine("Connection shut down.");
            serverSocket.Close();
        }
    }
}

Remarks

A buffer is a block of bytes in memory used to cache data, thereby reducing the number of calls to the operating system. Buffers improve read and write performance. A buffer can be used for either reading or writing, but never both simultaneously. The Read and Write methods of BufferedStream automatically maintain the buffer.

Important

This type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the "Using an Object that Implements IDisposable" section in the IDisposable interface topic.

BufferedStream can be composed around certain types of streams. It provides implementations for reading and writing bytes to an underlying data source or repository. Use BinaryReader and BinaryWriter for reading and writing other data types. BufferedStream is designed to prevent the buffer from slowing down input and output when the buffer is not needed. If you always read and write for sizes greater than the internal buffer size, then BufferedStream might not even allocate the internal buffer. BufferedStream also buffers reads and writes in a shared buffer. It is assumed that you will almost always be doing a series of reads or writes, but rarely alternate between the two of them.

Constructors

BufferedStream(Stream, Int32)

Initializes a new instance of the BufferedStream class with the specified buffer size.

BufferedStream(Stream)

Initializes a new instance of the BufferedStream class with a default buffer size of 4096 bytes.

Properties

BufferSize

Gets the buffer size in bytes for this buffered stream.

CanRead

Gets a value indicating whether the current stream supports reading.

CanSeek

Gets a value indicating whether the current stream supports seeking.

CanTimeout

Gets a value that determines whether the current stream can time out.

(Inherited from Stream)
CanWrite

Gets a value indicating whether the current stream supports writing.

Length

Gets the stream length in bytes.

Position

Gets the position within the current stream.

ReadTimeout

Gets or sets a value, in milliseconds, that determines how long the stream will attempt to read before timing out.

(Inherited from Stream)
UnderlyingStream

Gets the underlying Stream instance for this buffered stream.

WriteTimeout

Gets or sets a value, in milliseconds, that determines how long the stream will attempt to write before timing out.

(Inherited from Stream)

Methods

BeginRead(Byte[], Int32, Int32, AsyncCallback, Object)

Begins an asynchronous read operation. (Consider using ReadAsync(Byte[], Int32, Int32, CancellationToken) instead.)

BeginRead(Byte[], Int32, Int32, AsyncCallback, Object)

Begins an asynchronous read operation. (Consider using ReadAsync(Byte[], Int32, Int32) instead.)

(Inherited from Stream)
BeginWrite(Byte[], Int32, Int32, AsyncCallback, Object)

Begins an asynchronous write operation. (Consider using WriteAsync(Byte[], Int32, Int32, CancellationToken) instead.)

BeginWrite(Byte[], Int32, Int32, AsyncCallback, Object)

Begins an asynchronous write operation. (Consider using WriteAsync(Byte[], Int32, Int32) instead.)

(Inherited from Stream)
Close()

Closes the stream and releases any resources (especially system resources such as sockets and file handles) associated with the current buffered stream.

Close()

Closes the current stream and releases any resources (such as sockets and file handles) associated with the current stream. Instead of calling this method, ensure that the stream is properly disposed.

(Inherited from Stream)
CopyTo(Stream, Int32)

Reads the bytes from the current buffered stream and writes them to another stream.

CopyTo(Stream, Int32)

Reads the bytes from the current stream and writes them to another stream, using a specified buffer size. Both streams positions are advanced by the number of bytes copied.

(Inherited from Stream)
CopyTo(Stream)

Reads the bytes from the current stream and writes them to another stream. Both streams positions are advanced by the number of bytes copied.

(Inherited from Stream)
CopyToAsync(Stream, CancellationToken)

Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified cancellation token. Both streams positions are advanced by the number of bytes copied.

(Inherited from Stream)
CopyToAsync(Stream, Int32, CancellationToken)

Asynchronously reads the bytes from the current buffered stream and writes them to another stream, using a specified buffer size and cancellation token.

CopyToAsync(Stream, Int32, CancellationToken)

Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size and cancellation token. Both streams positions are advanced by the number of bytes copied.

(Inherited from Stream)
CopyToAsync(Stream, Int32)

Asynchronously reads the bytes from the current stream and writes them to another stream, using a specified buffer size. Both streams positions are advanced by the number of bytes copied.

(Inherited from Stream)
CopyToAsync(Stream)

Asynchronously reads the bytes from the current stream and writes them to another stream. Both streams positions are advanced by the number of bytes copied.

(Inherited from Stream)
CreateObjRef(Type)

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.

(Inherited from MarshalByRefObject)
CreateWaitHandle()
Obsolete.
Obsolete.
Obsolete.

Allocates a WaitHandle object.

(Inherited from Stream)
Dispose()

Releases all resources used by the Stream.

(Inherited from Stream)
Dispose(Boolean)

Releases the unmanaged resources used by the Stream and optionally releases the managed resources.

(Inherited from Stream)
DisposeAsync()

Asynchronously releases the unmanaged resources used by the buffered stream.

DisposeAsync()

Asynchronously releases the unmanaged resources used by the Stream.

(Inherited from Stream)
EndRead(IAsyncResult)

Waits for the pending asynchronous read operation to complete. (Consider using ReadAsync(Byte[], Int32, Int32, CancellationToken) instead.)

EndRead(IAsyncResult)

Waits for the pending asynchronous read to complete. (Consider using ReadAsync(Byte[], Int32, Int32) instead.)

(Inherited from Stream)
EndWrite(IAsyncResult)

Ends an asynchronous write operation and blocks until the I/O operation is complete. (Consider using WriteAsync(Byte[], Int32, Int32, CancellationToken) instead.)

EndWrite(IAsyncResult)

Ends an asynchronous write operation. (Consider using WriteAsync(Byte[], Int32, Int32) instead.)

(Inherited from Stream)
Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
Flush()

Clears all buffers for this stream and causes any buffered data to be written to the underlying device.

FlushAsync()

Asynchronously clears all buffers for this stream and causes any buffered data to be written to the underlying device.

(Inherited from Stream)
FlushAsync(CancellationToken)

Asynchronously clears all buffers for this stream, causes any buffered data to be written to the underlying device, and monitors cancellation requests.

FlushAsync(CancellationToken)

Asynchronously clears all buffers for this stream, causes any buffered data to be written to the underlying device, and monitors cancellation requests.

(Inherited from Stream)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetLifetimeService()
Obsolete.

Retrieves the current lifetime service object that controls the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
InitializeLifetimeService()
Obsolete.

Obtains a lifetime service object to control the lifetime policy for this instance.

(Inherited from MarshalByRefObject)
MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
MemberwiseClone(Boolean)

Creates a shallow copy of the current MarshalByRefObject object.

(Inherited from MarshalByRefObject)
ObjectInvariant()
Obsolete.

Provides support for a Contract.

(Inherited from Stream)
Read(Byte[], Int32, Int32)

Copies bytes from the current buffered stream to an array.

Read(Span<Byte>)

Copies bytes from the current buffered stream to a byte span and advances the position within the buffered stream by the number of bytes read.

Read(Span<Byte>)

When overridden in a derived class, reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.

(Inherited from Stream)
ReadAsync(Byte[], Int32, Int32, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

ReadAsync(Byte[], Int32, Int32, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

(Inherited from Stream)
ReadAsync(Byte[], Int32, Int32)

Asynchronously reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.

(Inherited from Stream)
ReadAsync(Memory<Byte>, CancellationToken)

Asynchronously reads a sequence of bytes from the current buffered stream and advances the position within the buffered stream by the number of bytes read.

ReadAsync(Memory<Byte>, CancellationToken)

Asynchronously reads a sequence of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

(Inherited from Stream)
ReadAtLeast(Span<Byte>, Int32, Boolean)

Reads at least a minimum number of bytes from the current stream and advances the position within the stream by the number of bytes read.

(Inherited from Stream)
ReadAtLeastAsync(Memory<Byte>, Int32, Boolean, CancellationToken)

Asynchronously reads at least a minimum number of bytes from the current stream, advances the position within the stream by the number of bytes read, and monitors cancellation requests.

(Inherited from Stream)
ReadByte()

Reads a byte from the underlying stream and returns the byte cast to an int, or returns -1 if reading from the end of the stream.

ReadExactly(Byte[], Int32, Int32)

Reads count number of bytes from the current stream and advances the position within the stream.

(Inherited from Stream)
ReadExactly(Span<Byte>)

Reads bytes from the current stream and advances the position within the stream until the buffer is filled.

(Inherited from Stream)
ReadExactlyAsync(Byte[], Int32, Int32, CancellationToken)

Asynchronously reads count number of bytes from the current stream, advances the position within the stream, and monitors cancellation requests.

(Inherited from Stream)
ReadExactlyAsync(Memory<Byte>, CancellationToken)

Asynchronously reads bytes from the current stream, advances the position within the stream until the buffer is filled, and monitors cancellation requests.

(Inherited from Stream)
Seek(Int64, SeekOrigin)

Sets the position within the current buffered stream.

SetLength(Int64)

Sets the length of the buffered stream.

ToString()

Returns a string that represents the current object.

(Inherited from Object)
Write(Byte[], Int32, Int32)

Copies bytes to the buffered stream and advances the current position within the buffered stream by the number of bytes written.

Write(ReadOnlySpan<Byte>)

Writes a sequence of bytes to the current buffered stream and advances the current position within this buffered stream by the number of bytes written.

Write(ReadOnlySpan<Byte>)

When overridden in a derived class, writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.

(Inherited from Stream)
WriteAsync(Byte[], Int32, Int32, CancellationToken)

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

WriteAsync(Byte[], Int32, Int32, CancellationToken)

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

(Inherited from Stream)
WriteAsync(Byte[], Int32, Int32)

Asynchronously writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.

(Inherited from Stream)
WriteAsync(ReadOnlyMemory<Byte>, CancellationToken)

Asynchronously writes a sequence of bytes to the current buffered stream, advances the current position within this buffered stream by the number of bytes written, and monitors cancellation requests.

WriteAsync(ReadOnlyMemory<Byte>, CancellationToken)

Asynchronously writes a sequence of bytes to the current stream, advances the current position within this stream by the number of bytes written, and monitors cancellation requests.

(Inherited from Stream)
WriteByte(Byte)

Writes a byte to the current position in the buffered stream.

Explicit Interface Implementations

IDisposable.Dispose()

Releases all resources used by the Stream.

(Inherited from Stream)

Extension Methods

CopyToAsync(Stream, PipeWriter, CancellationToken)

Asynchronously reads the bytes from the Stream and writes them to the specified PipeWriter, using a cancellation token.

ConfigureAwait(IAsyncDisposable, Boolean)

Configures how awaits on the tasks returned from an async disposable will be performed.

Applies to

Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.5, 1.6, 2.0, 2.1

See also