Open compressed files

[hombit]

Fips should open compressed files such as .fits.gz, .fits.zip, etc.

Qt has very limited support of uncompression that is used for its internal media data:

Note: If you want to use this function to uncompress external data that was compressed using zlib, you first need to prepend a four byte header to the byte array containing the data. The header must contain the expected length (in bytes) of the uncompressed data, expressed as an unsigned, big-endian, 32-bit integer.
https://doc.qt.io/qt-5/qbytearray.html#qUncompress

Qt uses the zlib library to provide compression. This means that you can compress and decompress your bytearrays of data using Qt. See the documentation on qUncompress() http://doc.qt.io/qt-5/qbytearray.html#qUncompress
Note that this does not produce file archives that can be opened by other applications, to do that you will need to write it yourself using Qt's custom file handling system http://doc.qt.io/qt-4.8/qabstractfileengine.html#details or use a 3rd party library.
https://wiki.qt.io/Technical_FAQ

[matwey]

https://heasarc.gsfc.nasa.gov/docs/software/fitsio/compression.html

[hombit]

https://heasarc.gsfc.nasa.gov/docs/software/fitsio/compression.html

I've opened separated issue #134 for compressed FITS data case.