FFI: Add ffi.istype() function.

1 files changed, 30 insertions, 0 deletions

diff --git a/src/lib_ffi.c b/src/lib_ffi.c
index fe84ca7d..27996f0e 100644
--- a/src/lib_ffi.c
+++ b/src/lib_ffi.c
@@ -456,6 +456,36 @@ LJLIB_CF(ffi_typeof)
   return 1;
 }
 
+LJLIB_CF(ffi_istype)    LJLIB_REC(ffi_istype)
+{
+  CTState *cts = ctype_cts(L);
+  CTypeID id1 = ffi_checkctype(L, cts);
+  TValue *o = lj_lib_checkany(L, 2);
+  int b = 0;
+  if (tviscdata(o)) {
+    GCcdata *cd = cdataV(o);
+    CTypeID id2 = cd->typeid == CTID_CTYPEID ? *(CTypeID *)cdataptr(cd) :
+                                               cd->typeid;
+    CType *ct1 = lj_ctype_rawref(cts, id1);
+    CType *ct2 = lj_ctype_rawref(cts, id2);
+    if (ct1 == ct2) {
+      b = 1;
+    } else if (ctype_type(ct1->info) == ctype_type(ct2->info) &&
+               ct1->size == ct2->size) {
+      if (ctype_ispointer(ct1->info))
+        b = lj_cconv_compatptr(cts, ct1, ct2, CCF_IGNQUAL);
+      else if (ctype_isnum(ct1->info) || ctype_isvoid(ct1->info))
+        b = (((ct1->info ^ ct2->info) & ~CTF_QUAL) == 0);
+    } else if (ctype_isstruct(ct1->info) && ctype_isptr(ct2->info) &&
+               ct1 == ctype_rawchild(cts, ct2)) {
+      b = 1;
+    }
+  }
+  setboolV(L->top-1, b);
+  setboolV(&G(L)->tmptv2, b);  /* Remember for trace recorder. */
+  return 1;
+}
+
 LJLIB_CF(ffi_sizeof)
 {
   CTState *cts = ctype_cts(L);