[PD-dev] Opening patches from libpd without accessing filesystem?

[Andi McClure]

Hi. I am embedding libpd into a video game. The video game targets
Android and so will be shipped in a configuration where assets are
bundled into a zip file (the APK) and decoded at runtime. Code does
not access the filesystem directly.

Looking at the libpd C sample, and also the documentation, it appears
the only way to get it to open a patch is `void *libpd_openfile(const
char *name, const char *dir)`. This appears to take an on-disk path to
the patch file directly and it appears sometimes it will open other
files from disk too (I guess pd files can reference external sound
files?). However, again, none of the files I will want it to open are
on the disk so it will not find them.

Is there a way around this? For example is there a backdoor to give
libpd a buffer in memory containing an already-loaded file? Or
callbacks to replace libpd's open/read file functions?

If this is not possible, it looks like I might be able to alter libpd
to add virtual filesystem abilities (for example, letting the library
user provide a table of surrogate openFile, readFile, closeFile
function pointers). It looks(?) like the filesystem access is pretty
neatly contained in s_path.c and m_binbuf.c. If I do this, would there
be interest in accepting the patch back upstream?