From c303478ad7b096b77bea419c8066a9b263822df4 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Fri, 15 Aug 2025 19:45:00 -0400
Subject: [PATCH] Avoid Utf8Dfa scan if there's no non-ascii

---
 src/parser3.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/parser3.h b/src/parser3.h
index 668f983..8de85bc 100644
--- a/src/parser3.h
+++ b/src/parser3.h
@@ -209,6 +209,7 @@ inline PRESERVE_NONE WeaselJsonStatus scan_string_impl(Parser3 *self,
   if (self->strDfa.accept()) {
     for (;;) {
       if (bufEnd - buf < V::lanes) [[unlikely]] {
+        buf = (char *)self->strDfa.scan(buf, bufEnd);
         break;
       }
       auto v = V{(int8_t *)buf};
@@ -217,13 +218,16 @@ inline PRESERVE_NONE WeaselJsonStatus scan_string_impl(Parser3 *self,
               .count_leading_nonzero_lanes();
       buf += normal;
       if (normal < V::lanes) {
+        if (buf != bufEnd && *buf < 0x20) {
+          buf = (char *)self->strDfa.scan(buf, bufEnd);
+        }
         break;
       }
     }
+  } else {
+    buf = (char *)self->strDfa.scan(buf, bufEnd);
   }
 
-  buf = (char *)self->strDfa.scan(buf, bufEnd);
-
   int len = buf - before;
   if (!(self->flags & WeaselJsonRaw)) {
     if (self->writeBuf != before) {