DeflateStream.Read Method (Byte(), Int32, Int32)


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Reads a number of decompressed bytes into the specified byte array.

Namespace:   System.IO.Compression
Assembly:  System (in System.dll)

Public Overrides Function Read (
	array As Byte(),
	offset As Integer,
	count As Integer
) As Integer


Type: System.Byte()

The array to store decompressed bytes.

Type: System.Int32

The byte offset in array at which the read bytes will be placed.

Type: System.Int32

The maximum number of decompressed bytes to read.

Return Value

Type: System.Int32

The number of bytes that were read into the byte array.

Exception Condition

array is null.


The CompressionMode value was Compress when the object was created.

- or -

The underlying stream does not support reading.


offset or count is less than zero.


array length minus the index starting point is less than count.


The data is in an invalid format.


The stream is closed.

The following example shows how to compress and decompress bytes by using the Read and Write methods.

Imports System.IO
Imports System.IO.Compression
Imports System.Text

Module Module1

    Sub Main()
        Dim uniEncode As UnicodeEncoding = New UnicodeEncoding()

        Dim bytesToCompress = uniEncode.GetBytes("example text to compress and decompress")
        Console.WriteLine("starting with: " + uniEncode.GetString(bytesToCompress))

        Using fileToCompress As FileStream = File.Create("examplefile.gz")
            Using compressionStream As DeflateStream = New DeflateStream(fileToCompress, CompressionMode.Compress)
                compressionStream.Write(bytesToCompress, 0, bytesToCompress.Length)
            End Using
        End Using

        Dim decompressedBytes(bytesToCompress.Length - 1) As Byte
        Using fileToDecompress As FileStream = File.Open("examplefile.gz", FileMode.Open)
            Using decompressionStream As DeflateStream = New DeflateStream(fileToDecompress, CompressionMode.Decompress)
                decompressionStream.Read(decompressedBytes, 0, bytesToCompress.Length)
            End Using
        End Using

        Console.WriteLine("ending with: " + uniEncode.GetString(decompressedBytes))
    End Sub
End Module

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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