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Samples of LIBFFI usage in pypy/rpython
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| # Simple sample of LIBFFI usage in pypy/rpython | |
| import sys | |
| from rpython.rtyper.lltypesystem import rffi, lltype | |
| from rpython.rlib import jit_libffi, rdynload, clibffi | |
| def entry_point(argv): | |
| lib = rdynload.dlopen('libSDL.so') | |
| SDL_Init = rdynload.dlsym(lib, "SDL_Init") | |
| argc = 1 | |
| # The cif is initialized with the stuff needed to call the function | |
| # In pixie the cif was built during the first call to the function. | |
| exchange_size = 0 | |
| exchange_arg0 = argc * rffi.sizeof(rffi.CCHARP) | |
| exchange_result = exchange_arg0 | |
| # ARG[0] | |
| exchange_result = exchange_size | |
| exchange_size += rffi.sizeof(rffi.LONG) | |
| # RETVAL | |
| exchange_result = exchange_size | |
| exchange_size += rffi.sizeof(rffi.LONG) | |
| cif = lltype.malloc(jit_libffi.CIF_DESCRIPTION, 1, flavor='raw') | |
| cif.abi = clibffi.FFI_DEFAULT_ABI | |
| cif.nargs = argc | |
| cif.rtype = clibffi.cast_type_to_ffitype(rffi.LONG) | |
| atypes = lltype.malloc(clibffi.FFI_TYPE_PP.TO, argc, flavor='raw') | |
| atypes[0] = clibffi.cast_type_to_ffitype(rffi.LONG) | |
| cif.atypes = atypes | |
| cif.exchange_size = exchange_size | |
| cif.exchange_result = exchange_result | |
| cif.exchange_result_libffi = exchange_result | |
| cif.exchange_args[0] = exchange_arg0 | |
| jit_libffi.jit_ffi_prep_cif(cif) | |
| # Exchange buffer is built for every call. Filled with arguments that are passed to the function. | |
| exc = lltype.malloc(rffi.CCHARP.TO, cif.exchange_size, flavor='raw') | |
| offset_p = rffi.ptradd(exc, cif.exchange_args[0]) | |
| pnt = rffi.cast(rffi.LONGP, offset_p) | |
| pnt[0] = rffi.cast(rffi.LONG, 0x00000020) # SDL_INIT_VIDEO | |
| offset_p = rffi.cast(rffi.CCHARP, rffi.ptradd(pnt, rffi.sizeof(rffi.LONG))) | |
| jit_libffi.jit_ffi_call(cif, SDL_Init, exc) | |
| offset_p = rffi.ptradd(exc, cif.exchange_result) | |
| retval = rffi.cast(rffi.LONGP, offset_p)[0] | |
| print "SDL_Init returned", retval | |
| lltype.free(exc, flavor='raw') | |
| return 0 | |
| def target(*args): | |
| return entry_point, None | |
| if __name__=='__main__': | |
| sys.exit(entry_point(sys.argv)) |
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