--- CBOR-XS/XS.xs	2016/04/24 20:08:41	1.54
+++ CBOR-XS/XS.xs	2016/11/25 12:16:12	1.57
@@ -667,9 +667,9 @@
 
 #define ERR(reason) SB if (!dec->err) dec->err = reason; goto fail; SE
 
-#define WANT(len) if (ecb_expect_false (dec->cur + len > dec->end)) ERR ("unexpected end of CBOR data")
+#define WANT(len) if (ecb_expect_false ((UV)(dec->end - dec->cur) < (UV)len)) ERR ("unexpected end of CBOR data")
 
-#define DEC_INC_DEPTH if (++dec->depth > dec->cbor.max_depth) ERR (ERR_NESTING_EXCEEDED)
+#define DEC_INC_DEPTH if (ecb_expect_false (++dec->depth > dec->cbor.max_depth)) ERR (ERR_NESTING_EXCEEDED)
 #define DEC_DEC_DEPTH --dec->depth
 
 static UV
@@ -756,7 +756,7 @@
     }
   else
     {
-      int i, len = decode_uint (dec);
+      UV i, len = decode_uint (dec);
 
       WANT (len); // complexity check for av_fill - need at least one byte per value, do not allow supersize arrays
       av_fill (av, len - 1);
@@ -783,7 +783,7 @@
   if (ecb_expect_true (!dec->stringref))
     if (ecb_expect_true ((U8)(*dec->cur - MAJOR_BYTES) <= LENGTH_EXT8))
       {
-        I32 len = decode_uint (dec);
+        STRLEN len = decode_uint (dec);
         char *key = (char *)dec->cur;
 
         WANT (len);
@@ -795,7 +795,7 @@
       }
     else if (ecb_expect_true ((U8)(*dec->cur - MAJOR_TEXT) <= LENGTH_EXT8))
       {
-        I32 len = decode_uint (dec);
+        STRLEN len = decode_uint (dec);
         char *key = (char *)dec->cur;
 
         WANT (len);
@@ -846,7 +846,9 @@
     }
   else
     {
-      int pairs = decode_uint (dec);
+      UV pairs = decode_uint (dec);
+
+      WANT (pairs); // complexity check - need at least one byte per value, do not allow supersize hashes
 
       while (pairs--)
         decode_he (dec, hv);
@@ -944,14 +946,16 @@
 
       case CBOR_TAG_STRINGREF_NAMESPACE:
         {
-          ENTER; SAVETMPS;
+          // do nmot use SAVETMPS/FREETMPS, as these will
+          // erase mortalised caches, e.g. "shareable"
+          ENTER;
 
           SAVESPTR (dec->stringref);
           dec->stringref = (AV *)sv_2mortal ((SV *)newAV ());
 
           sv = decode_sv (dec);
 
-          FREETMPS; LEAVE;
+          LEAVE;
         }
         break;
 
@@ -1394,6 +1398,8 @@
 
         sv_cbor = newSVpv ("CBOR", 0);
         SvREADONLY_on (sv_cbor);
+
+        assert (("STRLEN must be an unsigned type", 0 <= (STRLEN)-1));
 }
 
 PROTOTYPES: DISABLE