Limiting zip file size - vbscript

Question

I have a script in VBScript that gets the content of a folder and gets it into a zip. It is mainly based on what I found in another post, as I am no VBS expert. This is the function:
Sub ArchiveFolder (zipFile, sFolder)
With CreateObject("Scripting.FileSystemObject")
zipFile = .GetAbsolutePathName(zipFile)
sFolder = .GetAbsolutePathName(sFolder)
With .CreateTextFile(zipFile, True)
.Write Chr(80) & Chr(75) & Chr(5) & Chr(6) & String(18, chr(0))
End With
End With
With CreateObject("Shell.Application")
.NameSpace(zipFile).CopyHere .NameSpace(sFolder).Items
Do Until .NameSpace(zipFile).Items.Count = _
.NameSpace(sFolder).Items.Count
WScript.Sleep 1000
Loop
End With
End Sub
I need to divide the resulting file in size limited files (80MB). Is there a way to do this?
As I understand it, the Chr(80) & Chr(75) & Chr(5) & Chr(6) & String(18, chr(0)) part is indicating to create a zip file, but I am not able to find an explanation of what this means and how to parametrize the action.

Answer 1

The simplest approach to limiting the size of a zip file is to continue adding files until the maximum size is exceeded, then remove the last item added.
Sub ArchiveFolder (zipFile, sFolder)
With CreateObject("Scripting.FileSystemObject")
zipFile = .GetAbsolutePathName(zipFile)
sFolder = .GetAbsolutePathName(sFolder)
With .CreateTextFile(zipFile, True)
.Write Chr(80) & Chr(75) & Chr(5) & Chr(6) & String(18, chr(0))
End With
Set oZip = .GetFile(zipFile)
End With
With CreateObject("Shell.Application")
cnt = 0
For Each currentItem In .NameSpace(sFolder).Items
cnt = cnt + 1
.NameSpace(zipFile).CopyHere currentItem
Do Until .NameSpace(zipFile).Items.Count = cnt
WScript.Sleep 1000
Loop
If oZip.Size > 83886080 Then
Set lastItem = .NameSpace(zipFile).ParseName(f.Name)
.NameSpace("C:\temp").MoveHere lastItem
Exit For
End If
Next
End With
End Sub
Of course there are more intelligent strategies than this to optimize space usage, but exploring them would be far too broad for an answer here.

Answer 2

I have finally solved it by using 7zip's portable version. There I can create the zip file with the parameters I need:
Set oShell = CreateObject("WScript.Shell")
strCmd = "7-Zip\7z.exe a -v80m " & zipFile & " " & sFolder
oShell.Run(strCmd)
Set oShell = Nothing