Make DFA use hints.

Change-Id: I7b7b338a019ea19c4a99072c961dc6aa35c15915 Reviewed-on: https://code-review.googlesource.com/c/re2/+/49950 Reviewed-by: Paul Wankadia <[email protected]>
google · Dec 30, 2019 · f71aaa0 · f71aaa0
1 parent 7470f4d
commit f71aaa0
Showing 1 changed file with 15 additions and 2 deletions.
diff --git a/re2/dfa.cc b/re2/dfa.cc
@@ -971,8 +971,21 @@ void DFA::RunWorkqOnByte(Workq* oldq, Workq* newq,
         break;
 
       case kInstByteRange:   // can follow if c is in range
-        if (ip->Matches(c))
-          AddToQueue(newq, ip->out(), flag);
+        if (!ip->Matches(c))
+          break;
+        AddToQueue(newq, ip->out(), flag);
+        if (ip->hint() != 0) {
+          // We have a hint, but we must cancel out the
+          // increment that will occur after the break.
+          i += ip->hint() - 1;
+        } else {
+          // We have no hint, so we must find the end
+          // of the current list and then skip to it.
+          Prog::Inst* ip0 = ip;
+          while (!ip->last())
+            ++ip;
+          i += ip - ip0;
+        }
         break;
 
       case kInstMatch: