BufferedStream.Read Method
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| 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(Byte[], Int32, Int32) |
Copies bytes from the current buffered stream to an array. |
- Source:
- BufferedStream.cs
- Source:
- BufferedStream.cs
- Source:
- BufferedStream.cs
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.
public:
override int Read(Span<System::Byte> destination);public override int Read(Span<byte> destination);override this.Read : Span<byte> -> intPublic Overrides Function Read (destination As Span(Of Byte)) As IntegerParameters
A region of memory. When this method returns, the contents of this region are replaced by the bytes read from the current source.
Returns
The total number of bytes read into the buffer. This can be less than the number of bytes allocated in the buffer if that many bytes are not currently available, or zero (0) if the end of the stream has been reached.
Remarks
Use the CanRead property to determine whether the current instance supports reading. Use the ReadAsync method to read asynchronously from the current stream.
Implementations of this method read a maximum of buffer.Length bytes from the current stream and store them in buffer. The current position within the stream is advanced by the number of bytes read; however, if an exception occurs, the current position within the stream remains unchanged. Implementations return the number of bytes read. The implementation will block until at least one byte of data can be read, in the event that no data is available. Read returns 0 only when there is no more data in the stream and no more is expected (such as a closed socket or end of file). An implementation is free to return fewer bytes than requested even if the end of the stream has not been reached.
Use BinaryReader for reading primitive data types.
Applies to
.NET 10 and other versions
| Product | Versions |
|---|---|
| .NET | Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
- Source:
- BufferedStream.cs
- Source:
- BufferedStream.cs
- Source:
- BufferedStream.cs
Copies bytes from the current buffered stream to an array.
public:
override int Read(cli::array <System::Byte> ^ buffer, int offset, int count);public:
override int Read(cli::array <System::Byte> ^ array, int offset, int count);public override int Read(byte[] buffer, int offset, int count);public override int Read(byte[] array, int offset, int count);override this.Read : byte[] * int * int -> intoverride this.Read : byte[] * int * int -> intPublic Overrides Function Read (buffer As Byte(), offset As Integer, count As Integer) As IntegerPublic Overrides Function Read (array As Byte(), offset As Integer, count As Integer) As IntegerParameters
- bufferarray
- Byte[]
- offset
- Int32
The byte offset in the buffer at which to begin reading bytes.
- count
- Int32
The number of bytes to be read.
Returns
The total number of bytes read into array. This can be less than the number of bytes requested if that many bytes are not currently available, or 0 if the end of the stream has been reached before any data can be read.
Exceptions
Length of array minus offset is less than count.
array is null.
offset or count is negative.
The stream is not open or is null.
The stream does not support reading.
Methods were called after the stream was closed.
Examples
This code example is part of a larger example provided for the BufferedStream class.
// Receive data using the BufferedStream.
Console::WriteLine( "Receiving data using BufferedStream." );
bytesReceived = 0;
startTime = DateTime::Now;
while ( bytesReceived < numberOfLoops * receivedData->Length )
{
bytesReceived += bufStream->Read( receivedData, 0, receivedData->Length );
}
bufferedTime = (DateTime::Now - startTime).TotalSeconds;
Console::WriteLine( "{0} bytes received in {1} seconds.\n", bytesReceived.ToString(), bufferedTime.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"));
// Receive data using the BufferedStream.
printfn "Receiving data using BufferedStream."
bytesReceived <- 0
let startTime = DateTime.Now
let mutable numBytesToRead = receivedData.Length
let mutable broken = false
while not broken && numBytesToRead > 0 do
// Read may return anything from 0 to numBytesToRead.
let n = bufStream.Read(receivedData,0, receivedData.Length)
// The end of the file is reached.
if n = 0 then
broken <- true
else
bytesReceived <- bytesReceived + n
numBytesToRead <- numBytesToRead - n
let bufferedTime = (DateTime.Now - startTime).TotalSeconds
printfn $"{bytesReceived} bytes received in {bufferedTime:F1} seconds.\n"
' Receive data using the BufferedStream.
Console.WriteLine("Receiving data using BufferedStream.")
bytesReceived = 0
startTime = DateTime.Now
Dim numBytesToRead As Integer = receivedData.Length
Dim n As Integer
Do While numBytesToRead > 0
'Read my return anything from 0 to numBytesToRead
n = bufStream.Read(receivedData, 0, receivedData.Length)
'The end of the file is reached.
If n = 0 Then
Exit Do
End If
bytesReceived += n
numBytesToRead -= n
Loop
bufferedTime = DateTime.Now.Subtract(startTime).TotalSeconds
Console.WriteLine("{0} bytes received in {1} " & _
"seconds." & vbCrLf, _
bytesReceived.ToString(), _
bufferedTime.ToString("F1"))
Remarks
The Read method will return 0 only if the end of the stream is reached. In all other cases, Read always reads at least one byte from the stream before returning. By definition, if no data is available from the stream upon a call to Read, the Read method returns 0 (the end of the stream is reached automatically). An implementation is free to return fewer bytes than requested even if the end of the stream has not been reached.
Use BinaryReader for reading primitive data types.
See also
- BlockCopy(Array, Int32, Array, Int32, Int32)
- CanRead
- Write(Byte[], Int32, Int32)
- File and Stream I/O
- How to: Read Text from a File
- How to: Write Text to a File
Applies to
.NET 10 and other versions
| 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, 10 |
| .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 |
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