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

[Christof Ressi]

Hi, it's certainly possible to load Pd patches entirely from memory with 
a binbuf. In fact, Pd itself does this for its private hidden canvases. 
Checkout the patch "garray_arraytemplatefile" in g_array.c and 
garray_init() for how to read it.

Christof

On 04.05.2020 22:46, Andi McClure wrote:
> 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?
>
>
>
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