How to pack many files and install it with application

[deviouscode]

Hello All.

We developed a Qt application that require a lot of small images (~300) to be installed together with executable. Currently all images are stored as usual files and it is take to long to install the application from SIS package. In average it can take up to 20 minutes to install the application from downloaded SIS package.

In total SIS file have ~8 MB size so it can be installed much faster if somehow pack all these small files to one big data file. How it can be done in the best and Qt native way?

We are going to use SQLite database file and we would like to know if there is any other way? As I know we can load external binary resource file but it will be placed in RAM.

Could you please advice me how can we improve installation process of a Qt Symbian application with a lot of small files to be installed much quicker.

[danhicksbyron]

If you have lots of small read-only files (eg, icons, borders, etc) then the best thing to do is to put them in a resource file. However, a resource file becomes part of the load module and hence takes up real storage in runtime RAM -- not a good thing. So the size of resource files should be limited, using one only for things that are referenced commonly and frequently.

Otherwise, the only supported approach is to embed the files individually (though you can name them as a single directory in a single DEPLOYMENT statement).

It would be nice if Symbian supported accessing files directly from a "mounted" ZIP file, but there is no support for this, and neither is there support in Qt for opening/reading a ZIP so you could copy the files out on install. So you'd either have to roll-your-own Qt ZIP support or dig into Symbian code (where I've heard rumors that there are interfaces for reading ZIP files).

[danhicksbyron]

It would be interesting to try embedding small files in a SQL DB as BLOBs, then copying them out on install. The problem with this is that BLOBs aren't compressed like ZIP files, though this wouldn't be that big of a deal for (already compressed) image files.

Or you could come up with your own protocol for combining files into one large one. I suspect that installing one large file will go faster than many small ones, and copying out the files after install will be faster than installing them one-by-one.

[deviouscode]

Thank you danhicksbyron for your reply. It seems like the best way is using SQLite for my task.

[danhicksbyron]

Note that it would probably be best to not use the main DB for this, but a separate DB that is only opened for the duration needed.