--- CBOR-XS/XS.xs	2023/09/08 06:05:01	1.79
+++ CBOR-XS/XS.xs	2023/09/08 20:03:06	1.80
@@ -118,15 +118,16 @@
   // possibly future enhancements: (generic) float, (generic) string
 };
 
-#define F_SHRINK          0x00000001UL
-#define F_ALLOW_UNKNOWN   0x00000002UL
-#define F_ALLOW_SHARING   0x00000004UL
-#define F_ALLOW_CYCLES    0x00000008UL
-#define F_FORBID_OBJECTS  0x00000010UL
-#define F_PACK_STRINGS    0x00000020UL
-#define F_TEXT_KEYS       0x00000040UL
-#define F_TEXT_STRINGS    0x00000080UL
-#define F_VALIDATE_UTF8   0x00000100UL
+#define F_SHRINK            0x00000001UL
+#define F_ALLOW_UNKNOWN     0x00000002UL
+#define F_ALLOW_SHARING     0x00000004UL
+#define F_ALLOW_CYCLES      0x00000008UL
+#define F_ALLOW_WEAK_CYCLES 0x00000010UL
+#define F_FORBID_OBJECTS    0x00000020UL
+#define F_PACK_STRINGS      0x00000040UL
+#define F_TEXT_KEYS         0x00000080UL
+#define F_TEXT_STRINGS      0x00000100UL
+#define F_VALIDATE_UTF8     0x00000200UL
 
 #define INIT_SIZE   32 // initial scalar size to be allocated
 
@@ -1196,7 +1197,7 @@
           if (ecb_expect_false (!dec->shareable))
             dec->shareable = (AV *)sv_2mortal ((SV *)newAV ());
 
-          if (dec->cbor.flags & F_ALLOW_CYCLES)
+          if (ecb_expect_false (dec->cbor.flags & (F_ALLOW_CYCLES | F_ALLOW_WEAK_CYCLES)))
             {
               // if cycles are allowed, then we store an AV as value
               // while it is being decoded, and gather unresolved
@@ -1213,6 +1214,11 @@
               for (i = 0; i <= AvFILLp (av); ++i)
                 SvRV_set (AvARRAY (av)[i], SvREFCNT_inc_NN (SvRV (sv)));
 
+              // weaken all recursive references
+              if (dec->cbor.flags & F_ALLOW_WEAK_CYCLES)
+                for (i = 0; i <= AvFILLp (av); ++i)
+                  sv_rvweaken (AvARRAY (av)[i]);
+
               // now replace the AV by a reference to the completed value
               SvREFCNT_dec_NN ((SV *)av);
               AvARRAY (dec->shareable)[idx] = SvREFCNT_inc_NN (sv);
@@ -1241,13 +1247,13 @@
 
           // reference to cycle, we create a new \undef and use that, and also
           // registerr it in the AV for later fixing
-          if (SvTYPE (sv) == SVt_PVAV)
+          if (ecb_expect_false (SvTYPE (sv) == SVt_PVAV))
             {
               AV *av = (AV *)sv;
               sv = newRV_noinc (&PL_sv_undef);
               av_push (av, SvREFCNT_inc_NN (sv));
             }
-          else if (sv == &PL_sv_undef) // not yet decoded, but cycles not allowed
+          else if (ecb_expect_false (sv == &PL_sv_undef)) // not yet decoded, but cycles not allowed
             ERR ("cyclic CBOR data structure found, but allow_cycles is not enabled");
           else // we decoded the object earlier, no cycle
             sv = newSVsv (sv);
@@ -1678,15 +1684,16 @@
 
 void shrink (CBOR *self, int enable = 1)
 	ALIAS:
-        shrink          = F_SHRINK
-        allow_unknown   = F_ALLOW_UNKNOWN
-        allow_sharing   = F_ALLOW_SHARING
-        allow_cycles    = F_ALLOW_CYCLES
-        forbid_objects  = F_FORBID_OBJECTS
-        pack_strings    = F_PACK_STRINGS
-        text_keys       = F_TEXT_KEYS
-        text_strings    = F_TEXT_STRINGS
-        validate_utf8   = F_VALIDATE_UTF8
+        shrink            = F_SHRINK
+        allow_unknown     = F_ALLOW_UNKNOWN
+        allow_sharing     = F_ALLOW_SHARING
+        allow_cycles      = F_ALLOW_CYCLES
+        allow_weak_cycles = F_ALLOW_WEAK_CYCLES
+        forbid_objects    = F_FORBID_OBJECTS
+        pack_strings      = F_PACK_STRINGS
+        text_keys         = F_TEXT_KEYS
+        text_strings      = F_TEXT_STRINGS
+        validate_utf8     = F_VALIDATE_UTF8
 	PPCODE:
 {
         if (enable)
@@ -1699,15 +1706,16 @@
 
 void get_shrink (CBOR *self)
 	ALIAS:
-        get_shrink          = F_SHRINK
-        get_allow_unknown   = F_ALLOW_UNKNOWN
-        get_allow_sharing   = F_ALLOW_SHARING
-        get_allow_cycles    = F_ALLOW_CYCLES
-        get_forbid_objects  = F_FORBID_OBJECTS
-        get_pack_strings    = F_PACK_STRINGS
-        get_text_keys       = F_TEXT_KEYS
-        get_text_strings    = F_TEXT_STRINGS
-        get_validate_utf8   = F_VALIDATE_UTF8
+        get_shrink            = F_SHRINK
+        get_allow_unknown     = F_ALLOW_UNKNOWN
+        get_allow_sharing     = F_ALLOW_SHARING
+        get_allow_cycles      = F_ALLOW_CYCLES
+        get_allow_weak_cycles = F_ALLOW_WEAK_CYCLES
+        get_forbid_objects    = F_FORBID_OBJECTS
+        get_pack_strings      = F_PACK_STRINGS
+        get_text_keys         = F_TEXT_KEYS
+        get_text_strings      = F_TEXT_STRINGS
+        get_validate_utf8     = F_VALIDATE_UTF8
 	PPCODE:
         XPUSHs (boolSV (self->flags & ix));