Read Method (GZipCompressedStream)

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

Syntax

Visual Basic
C#

'Declaration
 
Public Overrides Function Read( _
   ByVal buffer() As Byte, _
   ByVal offset As Integer, _
   ByVal count As Integer _
) As Integer

'Usage
 
Dim instance As GZipCompressedStream
Dim buffer() As Byte
Dim offset As Integer
Dim count As Integer
Dim value As Integer
 
value = instance.Read(buffer, offset, count)

public override int Read( 
   byte[] buffer,
   int offset,
   int count
)

Parameters

buffer: An array of bytes containing the decompressed data. When this method returns, the buffer contains the specified byte array with the values between offset and (offset + nb bytes read) replaced by the bytes read from the current source.
offset: The zero-based byte offset in buffer at which to begin storing the data read from the current stream.
count: The maximum number of bytes to be read from the current stream.

Return Value

The total number of bytes read into the buffer. This may be less than the number of bytes requested if that many bytes are not currently available, or zero (0) if the end of the stream has been reached.

Example

The following example demonstrates how to read compressed data from a MemoryStream and decompress it to a FileStream using the GZipCompressedStream class.

Visual Basic
C#

Imports System.IO
Imports Xceed.Compression
Imports Xceed.Compression.Formats

' If you do not want the inner stream to be closed by the GZipCompressedStream
' then set the GZipCompressedStream's Transient property to true.
'
' The compressed data was compressed using the Compress example

Dim sourceStream = New MemoryStream(compressedData)
Dim gzip As New GZipCompressedStream(sourceStream)
Dim destinationStream As New FileStream("d:\data.txt", FileMode.OpenOrCreate)

' 32K at a time.
Dim buffer(32768) As Byte
Dim bytesRead As Integer = 0

' Loop until we have nothing more to read from the source stream
Do
      bytesRead = gzip.Read(buffer, 0, buffer.Length)
      
      If bytesRead &gt; 0 Then
            destinationStream.Write(buffer, 0, bytesRead)
      End If
Loop Until bytesRead = 0

' Close the destination stream and the GZipCompressedStream.
'
' Because the GZipCompressedStream will automatically close the source
' memory stream, there is no need to call Close once we are done with the stream.

destinationStream.Close()
gzip.Close()

using System.IO;
using Xceed.Compression;
using Xceed.Compression.Formats;

// Because the GZipCompressedStream will automatically close the source
// memory stream, there is no need to declare the memory stream within a using
// statement or to call Close once we are done with the stream.
//
// If you do not want the inner stream to be closed by the GZipCompressedStream
// then set the GZipCompressedStream's Transient property to true.
//
// The compressed data was compressed using the Compress example

MemoryStream sourceStream = new MemoryStream( compressedData );

using( GZipCompressedStream gzip = new GZipCompressedStream( sourceStream ) )
{
      using( FileStream destinationStream = new FileStream( @"d:\data.txt", FileMode.OpenOrCreate ) )
      {
            // 32K at a time.
            byte[] buffer = new byte[ 32768 ];
            int bytesRead = 0;
          
            // Loop until we have nothing more to read from the source stream.
            while( ( bytesRead = gzip.Read( buffer, 0, buffer.Length  ) ) &gt; 0 )
            {
                  destinationStream.Write( buffer, 0, bytesRead );
            }
      }
}

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

GZipCompressedStream Class
GZipCompressedStream Members
Base Implementation in Read