Wrapping fopencookie

[ksco]

This function is used by an old game running on ScummVM, and it takes a struct cookie_io_functions_t as an argument.

typedef struct {
   cookie_read_function_t  *read;
   cookie_write_function_t *write;
   cookie_seek_function_t  *seek;
   cookie_close_function_t *close;
} cookie_io_functions_t;

FILE *fopencookie(void *restrict cookie, const char *restrict mode,
                  cookie_io_functions_t io_funcs);

IIUC, A struct of this size will be directly passed through the stack, and it needs to be reconstructed on the fly when calling the native libs. The callback functions also need to be properly wrapped (i.e. GOM). Wrapper infra doesn't have support for this kind of function it seems.

A simple program for testing this function: https://ksco.cool/SAi4

[ptitSeb]

Mmmm, I need to think about this, but a signature like "pFEppV" should work. You than create

EXPORT void* my_fopencookie(x64emu_t* emu, vpod* cookie, void* mode, my_cookie_io_function_t* s)

That should work, as V will gives a pointer to pointing at the stack directly.

[ksco]

Oh! Indeed! Let me try it.