Re: [ft-devel] FT_Init_FreeType allocating memory before I get a chance to set the allocators.

[Mickey Gabel]

Werner LEMBERG wrote:
> > > > both FT_New_Memory, and FT_New_Library (functions called within
> > > > FT_Init_FreeType) are allocating memory, before I have a chance
> > > > of setting the function pointers in FT_Memory..  To get around
> > > > that I added an extra argument to the FT_Init_FreeType, which
> > > > allows me to provide an FT_Memory structure, before any other
> > > > freetype code is running.
> > > The `canonical' way is to replace ftsystem.c with something more
> > > appropriate for your target platform.  For example, you can copy
> > > the whole file, only replacing `FT_New_Memory' to fit your needs.
> > > I don't see an immediate need to add new API functions -- you have
> > > to convince me that the just outlined method doesn't work :-)
> > Sure I could do that... but then what is the point of having the
> > FT_Memory struct...it doesn't work as advertised, and in order to
> > fix it you advise me to replace a file where I need to implement my
> > own ft_alloc methods?
>
> Well, advise...  What I do is rather like taking a stab in the dark
> based on previous information :-)

We have had no problem using FT2 with our own allocators (we work on 
systems were malloc() and free(), and possibly dynamic allocation 
entirely, are not present)

So either I am doing it wrong, or Tom van Dick is doing it wrong.
Here's what I do:
1) We have our own struct that contains both the ft library and an 
FT_Memory object.
2) We initialize the fields in the FT_Memory object so that our 
callbacks are called.
3) We call FT_New_Library and tell it to use our memory object. This is 
the first FT2 API call.

        // Initialize freetype2
        lib->ft_memory.alloc = sf_FTalloc;
        lib->ft_memory.free  = sf_FTfree;
        lib->ft_memory.realloc       = sf_FTrealloc;
        lib->ft_memory.user  = lib;
        ft_err = FT_New_Library( &lib->ft_memory, &lib->ft_lib );

I've always felt that this is the way it's meant to be used! It doesn't 
look like a hack, and everything is documented. Also it works :)

Basically, if I understand correctly, what Tom asked is already there. 
There's no need to modify ft_system.c, or invent new API calls.