Xceed .NET Libraries Documentation
Xceed.Compression Assembly / Xceed.Compression Namespace / Compressor Class / Compress Method
An array of bytes to compress. A maximum of count bytes are taken from this array and compressed.
The byte offset in buffer at which to begin taking the data to compress.
The maximum number of bytes to be taken from buffer.
Indicates if this call ends the stream of data to compress.
An array of bytes containing the compressed data. Can be empty.


    Compress Method (Compressor)
    Compresses an array of bytes.
    Syntax
    'Declaration
     
    Public MustOverride Function Compress( _
       ByVal buffer() As Byte, _
       ByVal offset As Integer, _
       ByVal count As Integer, _
       ByVal endOfData As Boolean, _
       ByRef compressed() As Byte _
    ) As Integer
     
    'Usage
     
    Dim instance As Compressor
    Dim buffer() As Byte
    Dim offset As Integer
    Dim count As Integer
    Dim endOfData As Boolean
    Dim compressed() As Byte
    Dim value As Integer
     
    value = instance.Compress(buffer, offset, count, endOfData, compressed)

    Parameters

    buffer
    An array of bytes to compress. A maximum of count bytes are taken from this array and compressed.
    offset
    The byte offset in buffer at which to begin taking the data to compress.
    count
    The maximum number of bytes to be taken from buffer.
    endOfData
    Indicates if this call ends the stream of data to compress.
    compressed
    An array of bytes containing the compressed data. Can be empty.

    Return Value

    The number of bytes written to the compressed parameter.
    Remarks
    When the first call to Compress is made, a compression "session" is created. This session remains opened as long as Compress is called with the parameter endOfData set to False.

    During a compression session, the compression engine can choose to keep the data to compress in an internal buffer and return an empty array after a call to Compress. Many compression algorithms do this to get optimum compression by examining a certain number of bytes before compressing anything.

    A call to Compress with an empty buffer or a count of zero tells the compression engine to flush its internal buffer and return the compressed data. This may degrade the compression ratio.

    When Compress is called with the parameter endOfData set to True, the compression session is closed and all of the remaining compressed data is returned. The next call to Compress will create a new compression session.

    The compressed array may have a Length greater than the number of bytes returned by the call to Compress.

    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

    See Also