SocketAsyncEventArgs.SetBuffer Method

Definition

Initializes the data buffer to use with an asynchronous socket method.

Overloads

SetBuffer(Memory<Byte>)

Sets the region of memory to use as a buffer with an asynchronous socket method.

SetBuffer(Int32, Int32)

Sets the data buffer to use with an asynchronous socket method.

SetBuffer(Byte[], Int32, Int32)

Sets the data buffer to use with an asynchronous socket method.

Remarks

This method sets the Buffer property to null and the Count and Offset properties to zero.

SetBuffer(Memory<Byte>)

Sets the region of memory to use as a buffer with an asynchronous socket method.

public:
 void SetBuffer(Memory<System::Byte> buffer);
public void SetBuffer (Memory<byte> buffer);
member this.SetBuffer : Memory<byte> -> unit
Public Sub SetBuffer (buffer As Memory(Of Byte))

Parameters

buffer
Memory<Byte>

The region of memory to use as a buffer with an asynchronous socket method.

Remarks

This method sets the MemoryBuffer property to the buffer parameter, the Count property to the buffer length, and the Offset property to zero.

SetBuffer(Int32, Int32)

Sets the data buffer to use with an asynchronous socket method.

public:
 void SetBuffer(int offset, int count);
public void SetBuffer (int offset, int count);
member this.SetBuffer : int * int -> unit
Public Sub SetBuffer (offset As Integer, count As Integer)

Parameters

offset
Int32

The offset, in bytes, in the data buffer where the operation starts.

count
Int32

The maximum amount of data, in bytes, to send or receive in the buffer.

Exceptions

An argument was out of range. This exception occurs if the offset parameter is less than zero or greater than the length of the array in the Buffer property. This exception also occurs if the count parameter is less than zero or greater than the length of the array in the Buffer property minus the offset parameter.

Remarks

The offset and count parameters can't be negative numbers. The combination of the offset and count parameters must be in bounds of the buffer array in the Buffer property.

This method sets the Count property to the count parameter and the Offset property to the offset parameter. If the Buffer property is null, this method ignores the offset and count parameters and sets the Offset and Count properties to 0.

This method does not change the Buffer property.

See also

SetBuffer(Byte[], Int32, Int32)

Sets the data buffer to use with an asynchronous socket method.

public:
 void SetBuffer(cli::array <System::Byte> ^ buffer, int offset, int count);
public void SetBuffer (byte[] buffer, int offset, int count);
member this.SetBuffer : byte[] * int * int -> unit
Public Sub SetBuffer (buffer As Byte(), offset As Integer, count As Integer)

Parameters

buffer
Byte[]

The data buffer to use with an asynchronous socket method.

offset
Int32

The offset, in bytes, in the data buffer where the operation starts.

count
Int32

The maximum amount of data, in bytes, to send or receive in the buffer.

Exceptions

There are ambiguous buffers specified. This exception occurs if the Buffer property is also not null and the BufferList property is also not null.

An argument was out of range. This exception occurs if the offset parameter is less than zero or greater than the length of the array in the Buffer property. This exception also occurs if the count parameter is less than zero or greater than the length of the array in the Buffer property minus the offset parameter.

Examples

The following code example creates a single large buffer which can be divided up and assigned to SocketAsyncEventArgs objects for use with each socket I/O operation. This enables buffers to be easily reused and guards against fragmenting heap memory.

// This class creates a single large buffer which can be divided up
// and assigned to SocketAsyncEventArgs objects for use with each
// socket I/O operation.
// This enables bufffers to be easily reused and guards against
// fragmenting heap memory.
//
// The operations exposed on the BufferManager class are not thread safe.
class BufferManager
{
    int m_numBytes;                 // the total number of bytes controlled by the buffer pool
    byte[] m_buffer;                // the underlying byte array maintained by the Buffer Manager
    Stack<int> m_freeIndexPool;     //
    int m_currentIndex;
    int m_bufferSize;

    public BufferManager(int totalBytes, int bufferSize)
    {
        m_numBytes = totalBytes;
        m_currentIndex = 0;
        m_bufferSize = bufferSize;
        m_freeIndexPool = new Stack<int>();
    }

    // Allocates buffer space used by the buffer pool
    public void InitBuffer()
    {
        // create one big large buffer and divide that
        // out to each SocketAsyncEventArg object
        m_buffer = new byte[m_numBytes];
    }

    // Assigns a buffer from the buffer pool to the
    // specified SocketAsyncEventArgs object
    //
    // <returns>true if the buffer was successfully set, else false</returns>
    public bool SetBuffer(SocketAsyncEventArgs args)
    {

        if (m_freeIndexPool.Count > 0)
        {
            args.SetBuffer(m_buffer, m_freeIndexPool.Pop(), m_bufferSize);
        }
        else
        {
            if ((m_numBytes - m_bufferSize) < m_currentIndex)
            {
                return false;
            }
            args.SetBuffer(m_buffer, m_currentIndex, m_bufferSize);
            m_currentIndex += m_bufferSize;
        }
        return true;
    }

    // Removes the buffer from a SocketAsyncEventArg object.
    // This frees the buffer back to the buffer pool
    public void FreeBuffer(SocketAsyncEventArgs args)
    {
        m_freeIndexPool.Push(args.Offset);
        args.SetBuffer(null, 0, 0);
    }
}

Remarks

The offset and count parameters can't be negative numbers. The combination of the offset and count parameters must be in bounds of the data array in the buffer parameter.

This method sets the Buffer property to the buffer parameter, the Count property to the count parameter, and the Offset property to the offset parameter.

See also

Applies to