Ark, the file archiver and compressor developed by KDE, has seen a lot of development for the upcoming 16.12 release. This blog post provides a summary of the most important changes.

Advanced archive editing



Thanks to the excellent GSoC work done by Vladyslav Batyrenko (mvlabat) this summer, it’s now possible to perform advanced editing operations for an archive. This means that files/folders can be moved and copied within an archive. This functionality is available either from the context menu or with the well-known keyboard shortcuts (CTRL+C, CTRL+X, CTRL+V).

Additionally, files/folders can now be added to any subfolder of an archive. In the past files could only be added to the root of an archive. This is done by selecting a subfolder and then activating the “Add Files…” item from either the “Archive” menu or the context menu.

Finally, files/folders can be renamed. This can be done by selecting the entry and pressing F2 or selecting Rename from the context or “File” menu.

See mvlabat’s blog post for more info on these features.

Choose compression method



Ark now allows setting compression method for supported archives. This is possible for Zip and 7z archives. For instance, LZMA compression may be selected for Zip archives to improve compression ratio (requires 7z to be installed). Note that Zip archives using newer compression methods may not be supported by older unarchivers (e.g. the unzip utiliy), but should be supported by modern software such as WinZip, WinRar and 7-Zip for Windows. The compression method can be set in the Compression section when creating a new archive.







AES-encryption for Zip archives

Strong AES-encryption is now used by default for Zip archives when 7z is installed. Three AES key lengths are available (128, 192 and 256 bit). The classic Zip encryption method (ZipCrypto), which is now known to be vulnerable but is more widely supported, can also be selected. Again, note that e.g. unzip doesn’t support extracting archives with AES-encryption.

Support for AR archives



We added support for opening AR archives. This old Unix format is now mostly used for static libraries (*.a) on Linux systems. So static libraries can now be opened by Ark to view the contained object files.

Performance improvements

Opening large archives should be much faster with Ark 16.12. Previously, the model containing all the archive entries wasn’t created until the archive was completely loaded from disk. Now we start creating the model right away. This resulted in a greatly reduced time to open large archives.

Progress information

Ark now shows progress in percentage for more operations (e.g. open, extract, add) than previously. This means it’s possible to know approximately how long an operation will take. Additionally, progress is now always shown in Plasma’s system tray where operations can also be aborted. When progress in percentage is available it is also shown in the task manager item (thanks to KBroulik’s work).

Bugfixes and under-the-hood changes



A ton of bugs were fixed and the code architecture further modernized.



Testing and feedback

The 16.12 beta is now out, while the release candidate should be out on December 1st and the final release on December 15th. Please test the new features and provide feedback either as comments on this blog post or as bugs on KDE’s bugzilla

What’s next?

For Ark 17.04 we hope to add a graphical interface for configuring the plugins Ark uses to handle different archive formats. Also, we are investigating whether we can use libzip to handle zip archives.

If there are features you are missing in Ark, please let us know.

Acknowledgements



Thanks to Elvis Angelaccio and Vladyslav Batyrenko (mvlabat) for their development work on Ark.