VB6 - Zipper & ZipWriter, Zipping from VB programs

[dilettante]

Background

A lot of us find the need to create ZIP archives programmatically from time to time. There are a number of techniques we can use, from spawning external utility programs to 3rd party components to Shell automation.

Here is yet another way to accomplish this: using the free, open source zlibwapi.dll


Minizip

In addition to providing a STDCALL version of ZLib that we can call easily from VB6 programs zlibwapi.dll includes the Minizip project code as well.

Like a lot of open source hacked out by C coders this can be rough in many places, but it is widely used and well proven. It should have few if any bugs in the most recent version.

I'm using version 1.25 here. You can get this from:

Minizip: Zip and UnZip additionnal library

See the typo there? This is just one symptom of some of the issues, but fortunately the code at least seems to work fine even if its source is wonky with lots of flaws in comments and general documentation issues.

This DLL is not included in the attachment. You must download it yourself.

In zlib125dll.zip there is the Win32 Windows DLL of my Windows DLL named Zlibwapi.dll that contains both zLib and Minilib.

The file you want from this ZIP archive is:

zlib125dll.zip\dll32\zlibwapi.dll


ZipWriter

ZipWriter is a VB6 Class that wraps zlibwapi.dll to provide you with a way to create a ZIP archive and actually write data into it as archived files with no intermediate disk I/O steps.

You can use this as-is in many cases without the other code offered here.


Zipper

Zipper is a VB6 UserControl that wraps ZipWriter and a small helper ZipFile Class to give you the ability to create a ZIP archive (or add to an existing one) and add a list of disk files to it.

Zipper.Zip is an async operation and reports back progress, errors, and completion through several events. There is a Zipper.Cancel method if you need that.


ZipDemo

ZipDemo is a VB6 project that demonstrates use of the items described above.

You must download zlibwapi.dll and copy it into this project folder to run the program.

Much of the bulk of this attachment consists of the sample files in the "samples2" folder included.


There is a "ZipWriter" button that does a simple test of ZipWriter, creating a new ZIP archive "test.zip" with two files written to it. When that step completes the "Zipper" button is enabled.

The "Zipper" button tests Zipper, adding the files it finds in the "samples2" folder to the "test.zip" created in the first stage of the demo. While running a progressbar is updated and a "Cancel" button is enabled.

The "samples2" folder as supplied has just a few small files. Be sure to copy some larger files into it and rerun the program to see how things go with large files. The performance is fairly good.


Remarks

While you need to deploy zlibwapi.dll with your programs this is a standard DLL that you can feel free to place next to your EXE. No registration is required.

The results are better than those achieved using most other common techniques. Progress/Cancel/Complete can be really nice to have. There is no need for the shaky, convoluted, hackish window spelunking people often resort to when automating Shell objects.

There is a lot more you can do with zlibwapi.dll too. You can read from ZIP archives, unzip them, compress separate files outside of ZIP archives, compress/expand data in memory, etc. Even the huge-file Zip64 format is supported.

All you need is to write additional wrappers or just make the calls directly.

[dilettante]

Here is another demo. This one just shows creating a ZIP archive from a folder, but it also includes subfolders if any are present.

That is something not spelled out in the previous example.

Demo upon completion

The sample data is included.

[dilettante]

This is an update: Zipper 2 (version 2).

This expands the ZipWriter class to handle password encryption of archived files, and the ability to specify the timestamp to be recorded in the archive for each file.

The Zipper UserControl is expanded to accept file passwords and offers the option to use the disk file's LastUpdate timestamp instead of the result of the Now() function. This means Zipper has two helper classes now: ZipFile as before as well as the new ZipDateTimes. Nothing prevents the code in ZipDateTimes from being folded into Zipper itself, but keeping it separate helps keep Zipper at least a little easier to understand.


Once again, the point of Zipper is to make it easy to ZIP up one or more files asynchronously with progress updates and completion notification. The result is far cleaner than using hacks to try to detect when (and even if) a Shell32 ZIP process completes and completes properly.

A further enhancement might be the option to use the ZIP64 format to allow you to automate archiving of huge files. Note that until Windows Vista there was no File Explorer (Shell32) support for ZIP64.

[dilettante]

Version 2.1, which adds ZipperSync.

ZipperSync is a synchronous "clone" (very close copy) of the Zipper UserControl. ZipperSync may be a little easier to read because it doesn't have to use a time-slicing Timer to drive the I/O and processing.

If your files to ZIP up into an archive are fairly small so that you do not need async operation to remain responsive you might choose ZipperSync instead of Zipper.

The demo is very similar to the Zipper 2 Demo above.


Edit:

While hilarious if nobody had already downloaded it (not so funny since several people had), the attachment was a bit of a mess. It had a broken version of the new ZipperSync and was still using the Zipper control.

Attachment replaced. Sorry for the error.

[dilettante]

ZipperSync posted above is full of serious bugs!

These have been corrected, and a new AddBLOB() method has been added in version 2.2 posted here. This is being posted in a minimal project showing how easy it can be to use.

Note that the new AddBLOB() means I had to extend the ZipFile class. While Zipper.ctl has not had a similar AddBLOB() method added it should still work with the new ZipFile 2.2 as well.

AddBLOB() means you can add any arbitrary Byte array (BLOB) data as a "file" in the archive without writing it out as a temporary disk file.


A little confusing, but:

You can take (1.) the previous code posted above as version 2.1, (2.) replace all of the Zip*.* files by the new ones from this archive, and then (3.) everything should work fine (both Zipper 2 and ZipperSync 2.2).

In other words... I have not included Zipper.cls this time since it did not change. If I add BLOB support to it later I'll repost all of the Zip*.* files in a future attachment.


This ZipperSync class is very easy to use:

Private Sub cmdZipIt_Click()
    Dim TextBLOB() As Byte

    Text1.Enabled = False
    cmdZipIt.Enabled = False

    'Zip Text1.Text as "Text.txt" in "Sample.zip" archive:
    With New ZipperSync
        TextBLOB = StrConv(Text1.Text, vbFromUnicode) 'Store as ANSI.
        .AddBLOB TextBLOB, "Text.txt"
        .Zip App.Path & "\Sample.zip"
    End With

    lblStatus.Caption = "Complete"
End Sub

[dilettante]

A reminder:

See post #1 above, since you need a recent version of zlibwapi.dll for this to work. As mentioned above this is a "flat DLL" i.e. not an ActiveX DLL so it does not require registration.

[dilettante]

BTW:

I you can't or don't want to compile it yourself, there is a precompiled zlibwapi.dll version 1.2.8 at:

GlobalPlatform

This has zlib fixes beyond 1.2.5, and seems to work fine with my wrapper classes posted above.


Edit:

The page at that link no longer appears to offer precompiled binaries.

[dilettante]

In case it isn't clear, you can just skip the additional classes and use ZipWriter.cls alone if you are doing something very simple. Those other classes are used to abstract and "batch" the process of zipping multiple files. For a single file or two they may be more than you need.


Here I'm using the same ZipWriter version 2 from the last few uploads (again without error handling for simplification - don't do that!) to accomplish the same thing as the example in post #5 above:

Private Sub cmdZipIt_Click()
    Dim TextBLOB() As Byte

    Text1.Enabled = False
    cmdZipIt.Enabled = False

    'Zip Text1.Text as "Text.txt" in "Sample.zip" archive:
    With New ZipWriter
        TextBLOB = StrConv(Text1.Text, vbFromUnicode) 'Store as ANSI.
        .OpenZip App.Path & "\Sample.zip"
        .OpenFileInZip "Text.txt"
        .WriteBytes TextBLOB
        .CloseFileInZip
        .CloseZip
    End With

    lblStatus.Caption = "Complete"
End Sub

So you can just bypass the extra classes that wrap ZipWriter, write your own wrapper, or pull the definitions and logic from ZipWriter and use them inline within some other module (.BAS, .FRM, etc.).

ZipWriter itself contains the zlibwapi.dll definitions and wrapper logic, i.e. a "VB6 API binding" for the subset of zlibwapi.dll functionality required to create/write Zip archives.

[Dan_W]

Hi. Thank you for this, and for all your other posts and sample code (especially re: WIA).

I stumbled across this, and was intrigued. I've converted it to VBA 64bit, and have obtained a copy of the 64bit version of zlibwapi.dll. Using the most recent ZipWriter class, I can get it to create and compress a ZIP file. That part works perfectly.

The password element doesn't seem for me though. I can set a password, and unable to open the file until I enter the right password - but the problem is that even when I enter the correct password, it won't work. It presents an error message saying that what I've entered is incorrect.

Not sure if you've encountered this before, but just thought I'd flag it.

[xiaoyao]

Hi. Thank you for this, and for all your other posts and sample code (especially re: WIA).

I stumbled across this, and was intrigued. I've converted it to VBA 64bit, and have obtained a copy of the 64bit version of zlibwapi.dll. Using the most recent ZipWriter class, I can get it to create and compress a ZIP file. That part works perfectly.

The password element doesn't seem for me though. I can set a password, and unable to open the file until I enter the right password - but the problem is that even when I enter the correct password, it won't work. It presents an error message saying that what I've entered is incorrect.

Not sure if you've encountered this before, but just thought I'd flag it.

can you upload a VBA X64 DEMO XLSM demo? THANK YOU
it's also can use on twinbasic x64

[HackerVlad]

I would really like to have such a code only for the reverse action - for unpacking a ZIP file. Where can I find this code using this library?

[xiaoyao]

I would really like to have such a code only for the reverse action - for unpacking a ZIP file. Where can I find this code using this library?

MiniZip.cls , vb6 unzip File Class by zlibwapi.dll-VBForums
https://www.vbforums.com/showthread....y-zlibwapi-dll

[xiaoyao]

i unzip a excel file:test.xlsx,for download images,xml files:

unzip file by shell.application:

Duration: 866.4118 milliseconds [decompression 1]
Duration: 248.3394 milliseconds [decompression 2]
Duration: 395.8231 milliseconds [Extract image]
Duration: 489.3050 milliseconds [Extract image]

unzip by zlibwapi:

Duration: 2.9302 milliseconds [decompression 1]
Duration: 1.5231 milliseconds [decompression 2]
Duration: 1.5084 milliseconds [Extract image]
Duration: 1.7378 milliseconds [Extract image]

[HackerVlad]

i unzip a excel file:test.xlsx,for download images,xml files:

unzip file by shell.application:

Duration: 866.4118 milliseconds [decompression 1]
Duration: 248.3394 milliseconds [decompression 2]
Duration: 395.8231 milliseconds [Extract image]
Duration: 489.3050 milliseconds [Extract image]

unzip by zlibwapi:

Duration: 2.9302 milliseconds [decompression 1]
Duration: 1.5231 milliseconds [decompression 2]
Duration: 1.5084 milliseconds [Extract image]
Duration: 1.7378 milliseconds [Extract image]

And where is the class speed test from the wqeweto?
https://github.com/wqweto/ZipArchive

[xiaoyao]

And where is the class speed test from the wqeweto?
https://github.com/wqweto/ZipArchive

It's just the simplest excel file. You can add a few pictures and then copy the table. The entire file is actually a few hundred kilobytes.

[jdelano]

And where is the class speed test from the wqeweto?
https://github.com/wqweto/ZipArchive

I use this with twinBASIC for my super simply twinBASIC installer. It works great and super simple to use.

[HackerVlad]

I use this with twinBASIC for my super simply twinBASIC installer. It works great and super simple to use.

I also really like this class, but using it leads to an excessively large increase in the size of the EXE file. Therefore, it is better to use more compact (small) codes for simple unpacking.

[wqweto]

I also really like this class, but using it leads to an excessively large increase in the size of the EXE file. Therefore, it is better to use more compact (small) codes for simple unpacking.

You can try declaring ZIP_NOCOMPRESS = 1 in your project's Conditional Compilation if you are only going to extract files. Check out the source code near the begining, there are some more conditional compilation options.

Btw, nowadays Win10+ comes with libarchive built-in (in stdcall archiveint.dll) so this can be used to zip/unzip (or ungzip) and reduce cZipArchive's footprint on output binary by removing most of the ASM thunk *and* increase [de]compression performance in the meantime.

Another option on Win10+ is to shell tar.exe to zip/unzip e.g. c:> tar -caf d:\temp\aaa.zip d:\temp\bbb\*.*

cheers,
</wqw>

[xiaoyao]

You can try declaring ZIP_NOCOMPRESS = 1 in your project's Conditional Compilation if you are only going to extract files. Check out the source code near the begining, there are some more conditional compilation options.

Btw, nowadays Win10+ comes with libarchive built-in (in stdcall archiveint.dll) so this can be used to zip/unzip (or ungzip) and reduce cZipArchive's footprint on output binary by removing most of the ASM thunk *and* increase [de]compression performance in the meantime.

Another option on Win10+ is to shell tar.exe to zip/unzip e.g. c:> tar -caf d:\temp\aaa.zip d:\temp\bbb\*.*

cheers,
</wqw>

Libarchive (archiveint. DLL in stdcall). Is there a simple example? If this DLL is copied, can it be used on win7 and win8?

shell.application,This is equivalent to clicking on the decompression in the Explorer, all the same. It can take up to a second to extract a small file from an 20kb Excel file.
If the file is too large, a dialog box will pop up when he decompresses it, which will affect the user experience.
In fact, I feel that Microsoft should have added a zip decompression function in 1998 or even 2002. Every time Microsoft updates the system, it won't let us install the new framework of.net on top of the old system.
Adopting this kind of deep binding forces us to buy new computers.As a result, there are 10 different versions of.net SDK, all kinds of incompatibilities. (???????10??????.net sdk???????)

The zlib. DLL takes only 5 milliseconds to decompress.
So pure decompression, this is really convenient.

[HackerVlad]

I feel that Microsoft should have added a zip decompression function in 1998 or even 2002.

Yes, Microsoft did this in 2001, starting with Windows XP, there is a ZipFldr.dll library for this. But there is no documentation anywhere on how to use it, but The trick was able to make it work, and I'm currently studying its code and redoing it.

[HackerVlad]

You can try declaring ZIP_NOCOMPRESS = 1 in your project's

Following this advice helped reduce the size of the EXE by 30 KB. However, the class itself adds about 100 KB to the EXE anyway (which is quite a lot) and I don't like it. That's why I said that it's better to use other simpler and shorter codes for simple unpacking.

[xiaoyao]

Following this advice helped reduce the size of the EXE by 30 KB. However, the class itself adds about 100 KB to the EXE anyway (which is quite a lot) and I don't like it. That's why I said that it's better to use other simpler and shorter codes for simple unpacking.

You can make a universal interface. Use different DLLs, ZipFldr. DLL, zlib. DLL,
Implement compression or decompression.
Because different DLLs have different functions, each has its own advantages.
I support his password, and some versions are updated with stronger functions. Some of them are stable and very small.
If you want to draw a picture, you can use the gdiplus. DLL gdi32.dll, htmlcanv, SVG.?
For drawing ordinary graphics, we can make some general interfaces.
Let the old VB6 play more functions.

[wqweto]

That's why I said that it's better to use other simpler and shorter codes for simple unpacking.

Btw, which simpler and shorter codes do you talk about? Is there a simpler/shorter deflate algorithm implemented in VB6? Or PKWare ZIP format handling?

[HackerVlad]

Btw, which simpler and shorter codes do you talk about? Is there a simpler/shorter deflate algorithm implemented in VB6? Or PKWare ZIP format handling?

Well, I think the easiest way is to use the built-in Windows library ZipFldr.dll. Well, the simplest code from The Trick is generally few lines of code, but it requires a dependency in the form of olelib.tlb. Here is the code:

Option Explicit
Private Declare Function SHParseDisplayName Lib "shell32" (ByVal pszName As Long, ByVal IBindCtx As Long, ByRef ppidl As Long, sfgaoIn As Long, sfgaoOut As Long) As Long
Private Declare Function ILFree Lib "shell32" (ByVal pidlFree As Long) As Long
Private Declare Function lstrcpyn Lib "kernel32" Alias "lstrcpynW" (ByVal lpString1 As Long, ByVal lpString2 As Long, ByVal iMaxLength As Long) As Long
Private Declare Function lstrlen Lib "kernel32" Alias "lstrlenW" (ByVal lpString As Long) As Long

Private Const ZipFldrCLSID = "{E88DCCE0-B7B3-11d1-A9F0-00AA0060FA31}"
Private Const IID_IShellExtInit = "{000214E8-0000-0000-C000-000000000046}"
 
Private Sub Form_Load()
    Dim clsid   As UUID
    Dim iidSh   As UUID
    Dim shExt   As IShellExtInit
    Dim pf      As IPersistFolder2
    Dim pidl    As Long
    Dim file    As String
    Dim cb      As Long
    
    file = "D:\Temp\temp.zip"
    CLSIDFromString ZipFldrCLSID, clsid
    CLSIDFromString IID_IShellExtInit, iidSh
    
    If CoCreateInstance(clsid, Nothing, CLSCTX_INPROC_SERVER, iidSh, shExt) <> S_OK Then Exit Sub
    Set pf = shExt
    SHParseDisplayName StrPtr(file), 0, pidl, 0, 0
    pf.Initialize pidl
    ILFree pidl
    
    Dim srg     As IStorage
    Dim stm     As IStream
    Dim enm     As IEnumSTATSTG
    Dim itm     As STATSTG
    Dim nam     As String
    Dim buf()   As Byte
    Dim fnum    As Integer
    
    Set srg = pf
    Set enm = srg.EnumElements
    
    ReDim buf(&HFFFF&)
    
    enm.Reset
    Do While enm.Next(1, itm) = S_OK
        cb = lstrlen(itm.pwcsName)
        nam = Space(cb)
        lstrcpyn StrPtr(nam), itm.pwcsName, cb + 1
        CoTaskMemFree itm.pwcsName
        
        If itm.Type <> STGTY_STORAGE Then
            fnum = FreeFile
            Open "D:\temp\Testzip\" & nam For Binary As fnum
            
            Set stm = srg.OpenStream(nam, 0, STGM_READ, 0)
            
            Do
                cb = stm.Read(buf(0), UBound(buf) + 1)
                If cb = 0 Then Exit Do
                If cb <= UBound(buf) Then ReDim Preserve buf(cb - 1)
                Put #fnum, , buf()
            Loop
            Close fnum
        End If
    Loop
End Sub

And a more advanced same code from fafalone: https://www.vbforums.com/showthread....IStorage-based

But I was very upset that this code requires a TLB dependency. I tried to rewrite this code for myself to get rid of the addiction, but it didn't work out, it turned out to be too difficult.

[xiaoyao]

Well, I think the easiest way is to use the built-in Windows library ZipFldr.dll. Well, the simplest code from

Option Explicit
    Do While enm.Next(1, itm) = S_OK
        cb = lstrlen(itm.pwcsName)
        nam = Space(cb)
        lstrcpyn StrPtr(nam), itm.pwcsName, cb + 1
        CoTaskMemFree itm.pwcsName
        
        If itm.Type <> STGTY_STORAGE Then
            fnum = FreeFile
            Open "D:\temp\Testzip\" & nam For Binary As fnum
            
            Set stm = srg.OpenStream(nam, 0, STGM_READ, 0)
            
            Do
                cb = stm.Read(buf(0), UBound(buf) + 1)
                If cb = 0 Then Exit Do
                If cb <= UBound(buf) Then ReDim Preserve buf(cb - 1)
                Put #fnum, , buf()
            Loop
            Close fnum
        End If
    Loop
End Sub

And a more advanced same code from fafalone: https://www.vbforums.com/showthread....IStorage-based

But I was very upset that this code requires a TLB dependency. I tried to rewrite this code for myself to get rid of the addiction, but it didn't work out, it turned out to be too difficult.

Your method is very good. Compression and decompression are implemented with minimal code, and the running speed is still very fast.

it's by ai,I don't know if it's right.

Private Declare Function CreateZip Lib "ZipFldr.dll" (ByVal ZipFile As String) As Long
Private Declare Function AddZip Lib "ZipFldr.dll" (ByVal ZipFile As String, ByVal FileName As String, ByVal FilePath As String) As Long
Private Declare Function CloseZip Lib "ZipFldr.dll" (ByVal ZipFile As String) As Long
Sub CreateZipFile()
    Dim zipPath As String
    Dim filePath As String
    zipPath = "C:\test.zip"
    filePath = "C:\test.txt"
    Dim result As Long
    result = CreateZip(zipPath)
    If result = 0 Then
        result = AddZip(zipPath, "test.txt", filePath)
        If result = 0 Then
            result = CloseZip(zipPath)
            If result = 0 Then
                MsgBox "????"
            Else
                MsgBox "????????"
            End If
        Else
            MsgBox "??????????"
        End If
    Else
        MsgBox "????????"
    End If
End Sub

[HackerVlad]

Yes, I agree, this is a very good method. The code is minimal. After compilation, the EXE takes up only 20480 bytes.

[HackerVlad]

By the way, I found the simplest and shortest code in that topic: https://www.vbforums.com/showthread....=1#post5081447

    Dim oShell As Object
    Dim oFile As Object
    Dim Ret As Long
    
    Set oShell = CreateObject("Shell.Application")
    
    For Each oFile In oShell.NameSpace("D:\Temp\temp.zip").Items
        Ret = (oShell.NameSpace("D:\temp\Testzip\").CopyHere(oFile))
    Next

I just checked - everything is working! Oh my God, why did I bother with other codes then?..

P. S. But in XP, for some reason, this code didn't work for me.

[HackerVlad]

it's by ai,I don't know if it's right.

Private Declare Function CreateZip Lib "ZipFldr.dll" (ByVal ZipFile As String) As Long
Private Declare Function AddZip Lib "ZipFldr.dll" (ByVal ZipFile As String, ByVal FileName As String, ByVal FilePath As String) As Long
Private Declare Function CloseZip Lib "ZipFldr.dll" (ByVal ZipFile As String) As Long
Sub CreateZipFile()
    Dim zipPath As String
    Dim filePath As String
    zipPath = "C:\test.zip"
    filePath = "C:\test.txt"
    Dim result As Long
    result = CreateZip(zipPath)
    If result = 0 Then
        result = AddZip(zipPath, "test.txt", filePath)
        If result = 0 Then
            result = CloseZip(zipPath)
            If result = 0 Then
                MsgBox "????"
            Else
                MsgBox "????????"
            End If
        Else
            MsgBox "??????????"
        End If
    Else
        MsgBox "????????"
    End If
End Sub

Your artificial intelligence is complete nonsense! Such functions are included in libraries ZipFldr.dll It doesn't exist. There is no import table at all, this library is most likely implemented as a COM server.

[HackerVlad]

Btw, nowadays Win10+ comes with libarchive built-in (in stdcall archiveint.dll) so this can be used to zip/unzip (or ungzip) and reduce cZipArchive's footprint on output binary by removing most of the ASM thunk *and* increase [de]compression performance in the meantime.

Another option on Win10+ is to shell tar.exe to zip/unzip e.g. c:> tar -caf d:\temp\aaa.zip d:\temp\bbb\*.*

cheers,
</wqw>

Do you have an example of how the code for calling the library archiveint.dll works? I need an example of declarations and how to call them. Where can I see such a code?

[wqweto]

Do you have an example of how the code for calling the library archiveint.dll works? I need an example of declarations and how to call them. Where can I see such a code?

I have sample code for ungzip (linked above) only.

I just checked - everything is working! Oh my God, why did I bother with other codes then?..

Well, then we'll let you found out the problems with this code on your own :-)) It works on XP, that's not it. . .

cheers,
</wqw>

[HackerVlad]

I have sample code for ungzip (linked above) only.

Is there such a code just for packaging? Yes, thanks for finding it. Does this work on both 32-bit and 64-bit systems?

Private Declare Function archive_read_data Lib "archiveint" Alias "_archive_read_data@12" (ByVal hArchive As Long, pBuffer As Any, ByVal lSize As Long) As Long

[wqweto]

It's a Win10+ only feature. There is archiveint.dll in both C:\Windows\System32 and C:\Windows\SysWOW64 on my Win11 x64 box so it works from VB6 here.

Not sure if there is 32-bit version of Win11 though but if it existed it sure would have worked there too.

Btw, for API documentation you'll have to dig in https://github.com/libarchive/libarchive -- search for their bsdunzip.c sample code, it uses archive_read_support_format_zip in similar way gunzip sample code above does.

cheers,
</wqw>

[xiaoyao]

It's too hard. It feels like Microsoft just turned off our access to compressed files. Unless we use C , VB. net