I'm currently working on a project which involves reading file's magic files (without bindings). I'd like to know how it would be possible to read the file tests from the compiled binary magic.mgc directly, in another language (like Go), as I'm unsure of how its contents should be interpreted.
According to Christos Zoulas, main contributor of file:
If you want to use them directly you need to understand the binary format (which changes over time) and load it in your own data structures. [...] The code that parses the file is in apprentice.c. See check_buffer() for the reader and apprentice_compile() for the writer. There is a 4 byte magic number, followed by a 4 byte version number followed by MAGIG_SET (2) number of 4 byte counts one for each set (ascii, binary) followed by an array of 'struct magic' entries, in native byte format.
So that's the format one should expect! Nevertheless, it has to be parsed just like the raw files.