--- JSON-XS/XS.xs	2016/11/16 18:06:34	1.129
+++ JSON-XS/XS.xs	2016/11/26 06:09:29	1.130
@@ -8,6 +8,7 @@
 #include <stdio.h>
 #include <limits.h>
 #include <float.h>
+#include <inttypes.h>
 
 #if defined(__BORLANDC__) || defined(_MSC_VER)
 # define snprintf _snprintf // C compilers have this in stdio.h
@@ -363,7 +364,7 @@
 INLINE void
 need (enc_t *enc, STRLEN len)
 {
-  if (expect_false (enc->cur + len >= enc->end))
+  if (expect_false ((uintptr_t)(enc->end - enc->cur) < len))
     {
       STRLEN cur = enc->cur - (char *)SvPVX (enc->sv);
       SvGROW (enc->sv, cur + (len < (cur >> 2) ? cur >> 2 : len) + 1);