Open source embedded filesystem (or single file virtual filesystem, or structured storage) library for C

Question

I'm not sure what the "general" name of something like this might be. I'm looking for a library that gives me a file format to store different types of binary data in an expanding single file.

• open source, non-GPL (LGPL ok)
• C interface
• the file format is a single file
• multiple files within using a POSIX-like file API (or multiple "blobs" within using some other API)
• file/structure editing is done in-place
• reliable first, performant second

Examples include:

• the virtual drives of a virtual machine
• whefs
• HDF
• CDF
• NetCDF

Problems with the above:

• whefs doesn't appear to be very mature, but best describes what I'm after
• HDF, CDF, NetCDF are usable (also very reliable and fast), but they're rather complicated and I'm not entirely convinced of their support for opaque binary "blobs"

Edit:
Forgot to mention, one other relevant question:
http://stackoverflow.com/questions/1361560/simple-virtual-filesystem-in-c-c
Another similar question:
http://stackoverflow.com/questions/374417/is-there-an-open-source-alternative-to-windows-compound-files

Edit:
Added condition of in-place editing.

Answer 1

It sounds like you're talking about the Linux loopback device, which lets you treat a file on a filesystem as a first-class block device (and then proceed to mkfs, mount, etc.)

(What sort of platform are you targetting? A fully-featured Unixlike? Something in the embedded space with a small footprint?)

Answer 2

The WxWindows library supports ZIP files (see http://docs.wxwidgets.org/stable/wx_wxarc.html#wxarc). This has also the advantage that you can look at the contents using a ZIP manager (e.g. WINZIP).

A commercial alternative is ChillKat (http://www.chilkatsoft.com/)

If security is a concern, encrypt the file contents and mangle the file names in the ZIP archive.

Answer 3

This appears to do what I was looking for: libgsf

Still need to test its reliability/performance and how cross-platform the binary format is.

Answer 4

Eet library from the Enlightenment project maybe?

http://en.wikipedia.org/wiki/Enlightenment_Foundation_Libraries#EET http://docs.enlightenment.org/api/eet/html/

Answer 5

What about BerkeleyDB? It's not exactly a filesystem but it's quite transparent to store 'binary data' in a file. License seems to be quite permissive as well.