KMP string search using direct memory access and templates for type specialization.

src/jsregexp.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 213 matching lines @@
   SetElement(result, 0, Handle<Smi>(Smi::FromInt(value)));
   SetElement(result, 1, Handle<Smi>(Smi::FromInt(value + needle->length())));
   return result;
 }
 
 
 Handle<Object> RegExpImpl::AtomExecGlobal(Handle<JSRegExp> re,
                                           Handle<String> subject) {
   Handle<String> needle(String::cast(re->data()));
   Handle<JSArray> result = Factory::NewJSArray(1);
-  bool keep_going = true;
   int index = 0;
   int match_count = 0;
+  int subject_length = subject->length();
   int needle_length = needle->length();
-  while (keep_going) {
+  while (true) {
     LOG(RegExpExecEvent(re, index, subject));
-    int value = Runtime::StringMatchKmp(*subject, *needle, index);
+    int value = -1;
+    if (index + needle_length <= subject_length) {
+      value = Runtime::StringMatchKmp(*subject, *needle, index);
+    }
     if (value == -1) break;
     HandleScope scope;
     int end = value + needle_length;
     Handle<JSArray> pair = Factory::NewJSArray(2);
     SetElement(pair, 0, Handle<Smi>(Smi::FromInt(value)));
     SetElement(pair, 1, Handle<Smi>(Smi::FromInt(end)));
     SetElement(result, match_count, pair);
     match_count++;
     index = end;
     if (needle_length == 0)
@@ skipping 237 matching lines @@
 }
 
 
 ByteArray* RegExpImpl::JsreInternal(Handle<JSRegExp> re) {
   Object* value = re->data();
   ASSERT(value->IsFixedArray());
   return ByteArray::cast(FixedArray::cast(value)->get(INTERNAL_INDEX));
 }
 
 }}  // namespace v8::internal