Xojo Conferences

Platforms to show: All Mac Windows Linux Cross-Platform

/Compression/test huge files with small archive
Required plugins for this example: MBS Compression Plugin
You find this example project in your Plugins Download as a Xojo project file within the examples folder: /Compression/test huge files with small archive
This example is the version from Sun, 17th Mar 2012.
Project "test huge files with small archive.rbp"
MenuBar MenuBar1
MenuItem UntitledMenu1 = ""
MenuItem FileMenu = "&File"
MenuItem FileQuit = "Quit"
MenuItem EditMenu = "&Edit"
MenuItem EditUndo = "&Undo"
MenuItem UntitledMenu0 = "-"
MenuItem EditCut = "Cu&t"
MenuItem EditCopy = "&Copy"
MenuItem EditPaste = "&Paste"
MenuItem EditClear = "Clear"
End MenuBar
Class App Inherits Application
EventHandler Sub Open() // We write 15 GB of zeros into a Zip file and read it back to verify it writes correctly. // This tests whether we can handle more then 2 GB per file in a zip archive. // it does not test whether archives bigger than 2 GB work! const length = 10000000 // Make a 10 MB big string with only zeros dim m as new MemoryBlock(length) ZeroBuffer = m m = nil System.DebugLog "Start..." Write Read System.DebugLog "Finished." quit End EventHandler
Sub Read() dim f as FolderItem dim z as UnZipMBS dim s as string dim info as UnZipFileInfoMBS f=SpecialFolder.Desktop.Child("test.zip") z=new UnZipMBS(f) if z.Handle = 0 then MsgBox "Failed to open zip file." Return end if z.GoToFirstFile if z.Lasterror <> 0 then MsgBox "GoToFirstFile: "+str(z.Lasterror) Return end if do info=z.FileInfo System.DebugLog "Reading file: "+z.FileName // filename like test1.txt" dim size as integer = val(mid(z.FileName,5,1)) z.OpenCurrentFile if z.Lasterror <> 0 then MsgBox "GoToFirstFile: "+str(z.Lasterror) Return end if for g as integer = 1 to size for n as integer = 1 to 100 s = z.ReadCurrentFile(lenb(ZeroBuffer)) if s<>ZeroBuffer then break MsgBox "Failed: Data not correct. Buffer read too small." Return end if s = z.ReadCurrentFile(1) dim code as integer = asc(s) if code<>n then break MsgBox "Failed: Data not correct. Checkcode wrong: "+str(code)+"<>"+str(n) Return end if next next System.DebugLog "Read "+Format(z.Position/1000/1000, "0")+" MB" z.CloseCurrentFile z.GoToNextFile loop until z.Lasterror<>0 MsgBox "Everything okay." End Sub
Sub Write() dim z as ZipMBS dim f as FolderItem dim d as new date dim info as ZipFileInfoMBS f=SpecialFolder.Desktop.Child("test.zip") z=new ZipMBS(f,0) // we create files from 1 to 5 GB inside the zip for i as integer = 1 to 5 info=new ZipFileInfoMBS info.SetDate d info.ExternalFileAttributes=0 info.InternalFileAttributes=0 info.DosDate=0 // auto System.DebugLog "Write test"+str(i)+".txt with "+stR(i)+" GB." z.CreateFile("test"+str(i)+".txt", info, "", "", "", z.MethodDeflated, z.CompressionBestCompression, true) // for each GB for j as integer = 1 to i // write a little bit more than 1 GB for k as integer = 1 to 100 z.Write ZeroBuffer z.Write chrb(k) next next z.CloseFile next z.Close("global comment") z = nil End Sub
Property ZeroBuffer As string
End Class
Filetype text
End FileTypes
End Project

See also:

Feedback, Comments & Corrections

The items on this page are in the following plugins: MBS Compression Plugin.

MBS Xojo Plugins