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FFI: Simplify logic for pointer arithmetic.

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This commit is contained in:
Mike Pall 2011-01-12 21:34:11 +01:00
parent a5e48285e3
commit e7b08b2361
1 changed files with 5 additions and 13 deletions
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18
src/lib_ffi.c
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@ -94,15 +94,13 @@ static void ffi_checkarith(lua_State *L, CTState *cts, FFIArith *fa)
for (i = 0; i < 2; i++, o++) {
if (tviscdata(o)) {
GCcdata *cd = cdataV(o);
CTypeID id = (CTypeID)cd->typeid;
CType *ct = ctype_get(cts, id);
CType *ct = ctype_raw(cts, (CTypeID)cd->typeid);
uint8_t *p = (uint8_t *)cdataptr(cd);
if (ctype_isref(ct->info)) {
lua_assert(ct->size == CTSIZE_PTR);
p = *(uint8_t **)p;
id = ctype_cid(ct->info);
if (ctype_isptr(ct->info)) {
p = (uint8_t *)cdata_getptr(p, ct->size);
if (ctype_isref(ct->info)) ct = ctype_rawchild(cts, ct);
}
fa->ct[i] = ctype_raw(cts, id);
fa->ct[i] = ct;
fa->p[i] = p;
} else if (tvisnum(o)) {
fa->ct[i] = ctype_get(cts, CTID_DOUBLE);
@ -134,10 +132,6 @@ static int ffi_arith_ptr(lua_State *L, CTState *cts, FFIArith *fa, MMS mm)
sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
if (sz == 0 || sz == CTSIZE_INVALID)
lj_err_caller(L, LJ_ERR_FFI_INVSIZE);
if (ctype_isptr(ctp->info))
pp = (uint8_t *)cdata_getptr(pp, ctp->size);
if (ctype_isptr(fa->ct[1]->info))
fa->p[1] = (uint8_t *)cdata_getptr(fa->p[1], fa->ct[1]->size);
diff = ((intptr_t)pp - (intptr_t)fa->p[1]) / (int32_t)sz;
/* All valid pointer differences on x64 are in (-2^47, +2^47),
** which fits into a double without loss of precision.
@ -162,8 +156,6 @@ static int ffi_arith_ptr(lua_State *L, CTState *cts, FFIArith *fa, MMS mm)
sz = lj_ctype_size(cts, ctype_cid(ctp->info)); /* Element size. */
if (sz == CTSIZE_INVALID)
lj_err_caller(L, LJ_ERR_FFI_INVSIZE);
if (ctype_isptr(ctp->info))
pp = (uint8_t *)cdata_getptr(pp, ctp->size);
pp += idx*(int32_t)sz; /* Compute pointer + index. */
id = lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|ctype_cid(ctp->info)),
CTSIZE_PTR);