cZipArchive
A single-class pure VB6 library for zip archives management
Usage
Just include cZipArchive.cls to your project and start using instances of the class like this:
Simple compression
With New cZipArchive
.AddFile App.Path & "\your_file"
.CompressArchive App.Path & "\test.zip"
End With
Compress all files and sub-folders
With New cZipArchive
.AddFromFolder "C:\Path\To\*.*", Recursive:=True
.CompressArchive App.Path & "archive.zip"
End With
Decompress all files from archive
With New cZipArchive
.OpenArchive App.Path & "\test.zip"
.Extract "C:\Path\To\extract_folder"
End With
Method Extract can optionally filter on file mask (e.g. Filter:="*.doc"), file index (e.g. Filter:=15) or array of booleans with each entry to decompress index set to True.
Extract single file to target filename
OutputTarget can include a target new_filename to be used when extracting a specific file from the archive.
With New cZipArchive
.OpenArchive App.Path & "\test.zip"
.Extract "C:\Path\To\extract_folder\new_filename", Filter:="your_file"
End With
Get archive entry uncompressed size
By using FileInfo property keyed on entry filename in first parameter and zipIdxSize like this
With New cZipArchive
.OpenArchive App.Path & "\test.zip"
Debug.Print .FileInfo("report.pdf", zipIdxSize)
End With
List files in zip archive
By using FileInfo propery keyed on entry numeric index in first parameter like this
Dim lIdx As Long
With New cZipArchive
.OpenArchive App.Path & "\test.zip"
For lIdx = 0 To .FileCount - 1
Debug.Print "FileName=" & .FileInfo(lIdx, zipIdxFileName) & ", Size=" & .FileInfo(lIdx, zipIdxSize)
Next
End With
Here is a list of available values for the second parameter of FileInfo:
| Name | |
|---|---|
0 |
zipIdxFileName |
1 |
zipIdxAttributes |
2 |
zipIdxCrc32 |
3 |
zipIdxSize |
4 |
zipIdxCompressedSize |
5 |
zipIdxComment |
6 |
zipIdxLastModified |
7 |
zipIdxMethod |
8 |
zipIdxOffset |
9 |
zipIdxFlags |
Encryption support
Make sure to set Conditional Compilation in Make tab in project's properties dialog to include ZIP_CRYPTO = 1 setting for crypto support to get compiled from sources. By default crypto support is not compiled to reduce footprint on the final executable size.
With New cZipArchive
.OpenArchive App.Path & "\test.zip"
.Extract App.Path & "\test", Password:="123456"
End With
Use Password parameter on AddFile method together with EncrStrength parameter to set crypto used when creating archive.
| EncrStrength | Mode |
|---|---|
0 |
ZipCrypto (default) |
1 |
AES-128 |
2 |
AES-192 |
3 |
AES-256 (recommended) |
Note that default ZipCrypto encryption is weak but this is the only option which is compatible with Windows Explorer built-in zipfolders support.
In-memory operations
Sample utility function ReadBinaryFile in /test/basic/Form1.frm returns byte array with file's content.
Dim baZip() As Byte
With New cZipArchive
.AddFile ReadBinaryFile("sample.pdf"), "report.pdf"
.CompressArchive baZip
End With
WriteBinaryFile "test.zip", baZip
Method Extract accepts byte array target too.
Dim baOutput() As Byte
With New cZipArchive
.OpenArchive ReadBinaryFile("test.zip")
.Extract baOutput, Filter:=0 '--- archive's first file only
End With
ToDo (not supported yet)
- Deflate64 (de)compressor
- VBA7 (x64) support