well let i first explain in more detail what i mean

I would like to compress a string that i am gonna send through a
remoting object that is wrapped in a webservice on a local network
to a VB6 / Delphi win32 forms client


so it should be a algorythm that is availlable in VB.Net and VB6 / Delphi

anyone a good suggestion ???

M. Posseth,

There is no VBNet library for that. When you search this newsgroup than you
find a lot of samples.

My expirience with the previous version of this one is good.

http://www.gzip.org/zlib/

While I saw that it supports many platfoms.

I hope this helps a little bit?

Cor

Cor Ligthert wrote:
Show quoteHide quotewell i was more thinking about a algorythm that is commonly availlable
on these platforms

Something like huffman three  ( a algorythm that is good in plain text
compression )   however did not found a VB.Net version for that one ( or
other managed version, i do not mind to include a C# dll for instance  )


my project must consist completely from managed code, but the client
must be capable of working in complete unmanaged code binaries ( for
clients that do not have the framework installed )

Thanks for thinking with me


Michel Posseth

#ziplib supports huffman compression/decompression.

http://www.icsharpcode.net/OpenSource/SharpZipLib/Default.aspx

HTH,

Sam


Show quoteHide quoteB-Line is now hiring one Washington D.C. area VB.NET
developer for WinForms + WebServices position. 
Seaking mid to senior level developer.  For
information or to apply e-mail resume to
sam_blinex_com.

If you want a compression then I suggest Huffman compression, but there are
no examples of this in VB.NET, but there are in VB6. If you do convert it to
VB.NET then please post the code here.

Here's a link to a VB6 project if you want to convert it:

http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=11000&lngWId=1

I hope this is of help to you

Hello Crouchie

Thanks for the link this code should not be so difficult to convert to
VB.Net   ,, i was already thinking about the huffman algorythm as i know
that it is verry strong on string values
and as far as i know it should also be possible to make it easily in Delphi


Well i will probably end up in writing one in VB.Net and Delphi   as you
just saved me the VB6 version :-)

when it is finished i will post the link were to download it


Michel Posseth






http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=11000&lngWId=1
Show quoteHide quote

Heres a couple of classes the compress and decompress data:

'DATACOMPRESS CLASS - VB.Net '**********************************************************************************************************
'   METHODS:
'       CompressBytes(Source ByteArray, Optional Temporay Byte Array 
'               Compresses ByteArray into Temporary Byte Array or into
ByteArray if Temporary Byte Array not input
'
'       DeCompressBytes (Source ByteArray, Original Array Size before
compression as integer, Optional Temporary Byte Array)
'               Decompresses ByteArray into Temporary Byte Array or into
ByteArray if Temporary Byte Array not input
' '***********************************************************************************************************
Imports System.Runtime.InteropServices

Public Class CompressData

    'Declare zlib functions "Compress" and "Uncompress" for compressing Byte
Arrays
    <DllImport("zlib.DLL", EntryPoint:="compress")> _
Private Shared Function CompressByteArray(ByVal dest As Byte(), ByRef
destLen As Integer, ByVal src As Byte(), ByVal srcLen As Integer) As Integer
        ' Leave function empty - DLLImport attribute forwards calls to
CompressByteArray to compress in zlib.dLL
    End Function
    <DllImport("zlib.DLL", EntryPoint:="uncompress")> _
Private Shared Function UncompressByteArray(ByVal dest As Byte(), ByRef
destLen As Integer, ByVal src As Byte(), ByVal srcLen As Integer) As Integer
        ' Leave function empty - DLLImport attribute forwards calls to
UnCompressByteArray to Uncompress in zlib.dLL
    End Function

    Public Sub New()
        MyBase.New()
    End Sub

    Public Function CompressBytes(ByRef Data() As Byte, Optional ByRef
TempBuffer() As Byte = Nothing) As Integer
        'Compresses Data into a temp buffer
        'Returns compressed Data in Data if TempBuff not specified
        'Returns Result = Size of compressed data if ok, -1 if compression
failed
        Dim OriginalSize As Long = UBound(Data) + 1
        'Allocate temporary Byte Array for storage
        Dim result As Integer
        Dim usenewstorage As Boolean
        If TempBuffer Is Nothing Then usenewstorage = False Else
usenewstorage = True
        Dim BufferSize As Integer = UBound(Data) + 1
        BufferSize = CInt(BufferSize + (BufferSize * 0.01) + 12)
        ReDim TempBuffer(BufferSize)
        'Compress data byte array
        result = CompressByteArray(TempBuffer, BufferSize, Data,
UBound(Data) + 1)
        'Store results
        If result = 0 Then
            If usenewstorage Then
                'Return results in TempBuffer
                ReDim Preserve TempBuffer(BufferSize - 1)
            Else
                'Return compressed Data in original Data Array
                '      Resize original data array to compressed size
                ReDim Data(BufferSize - 1)
                '       Copy Array to original data array
                Array.Copy(TempBuffer, Data, BufferSize)
                'Release TempBuffer STorage
                TempBuffer = Nothing
            End If
            Return BufferSize
        Else
            Return -1
        End If
    End Function
    Public Function DeCompressBytes(ByRef Data() As Byte, ByVal Origsize As
Integer, Optional ByRef TempBuffer() As Byte = Nothing) As Integer
        'DeCompresses Data into a temp buffer..note that Origsize must be
the size of the original data before compression
        'Returns compressed Data in Data if TempBuff not specified
        'Returns Result = Size of decompressed data if ok, -1 if not
        'Allocate memory for buffers
        Dim result As Integer
        Dim usenewstorage As Boolean
        Dim Buffersize As Integer = CInt(Origsize + (Origsize * 0.01) + 12)
        If TempBuffer Is Nothing Then usenewstorage = False Else
usenewstorage = True
        ReDim TempBuffer(Buffersize)

        'Decompress data
        result = UncompressByteArray(TempBuffer, Origsize, Data,
UBound(Data) + 1)

        'Truncate buffer to compressed size
        If result = 0 Then
            If usenewstorage Then
                'Return decoompressed data in TempBuffer
                ReDim Preserve TempBuffer(Origsize - 1)
            Else
                'Return decompressed data in original source data file
                '       Truncate to compressed size
                ReDim Data(Origsize - 1)
                '       Copy Array to original data array
                Array.Copy(TempBuffer, Data, Origsize)
                'Release TempBuffer STorage
                TempBuffer = Nothing
            End If
            Return Origsize
        Else
            Return -1
        End If
    End Function


    Protected Overrides Sub Finalize()
        MyBase.Finalize()
    End Sub
    'Test routines for this class:
    'Testing - Remove
    'Dim sdata As Byte() = New Byte() {}
    'Dim fs As FileStream = New FileStream("C:\Programming\VS-Help Docs\Misc
NewsGroup Articles.doc", FileMode.Open, FileAccess.Read)
    'Dim rnew As BinaryReader = New BinaryReader(fs)
    '       sdata = rnew.ReadBytes(CInt(fs.Length))
    '      r.Close()
    '     fs.Close()
    'Dim ucomp As Integer = UBound(sdata, 1) + 1
    'Dim compsize As Integer = cmp.CompressBytes(sdata)
    'Dim uncompsize As Integer = cmp.DeCompressBytes(sdata, ucomp)
    'End TEsting

End Class


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