[szs] MK8: Remove sneaky reliance on unsigned underflow for range che…

…ck (from implicit conversion)

source/szs/src/MK8.hpp

@@ -107,7 +107,7 @@ static inline bool search(Match& match, const s32 search_pos_immut,
 
   // There are no deletions from the hash chains; the algorithm
   //  simply discards matches that are too old.
-  if (data_pos - search_pos > SEARCH_WINDOW_SIZE) {
+  if (search_pos > data_pos || data_pos > search_pos + SEARCH_WINDOW_SIZE) {
     return false;
   }
 
@@ -161,6 +161,8 @@ static inline bool search(Match& match, const s32 search_pos_immut,
     }
 
     search_pos = work.search_pos(search_pos);
+    // There are no deletions from the hash chains; the algorithm
+    //  simply discards matches that are too old.
     if (search_pos <= search_pos_min) {
       break;
     }