1 files changed, 35 insertions, 27 deletions
diff --git a/utf8.c b/utf8.c
index be75891a00..ecc77c009e 100644
--- a/utf8.c
+++ b/utf8.c
@@ -186,40 +186,48 @@ will be returned if it is valid, otherwise 0.
 STRLEN
 Perl_is_utf8_char(pTHX_ const U8 *s)
 {
-    U8 u = *s;
-    STRLEN slen, len;
-    UV uv, ouv;
+    STRLEN len;
+#ifdef IS_UTF8_CHAR
+    len = UTF8SKIP(s);
+    if (len <= 4)
+        return IS_UTF8_CHAR(s, len) ? len : 0;
+#endif /* #ifdef IS_UTF8_CHAR */
+    {
+	U8 u = *s;
+        STRLEN slen;
+        UV uv, ouv;
 
-    if (UTF8_IS_INVARIANT(u))
-	return 1;
+        if (UTF8_IS_INVARIANT(u))
+            return 1;
 
-    if (!UTF8_IS_START(u))
-	return 0;
+        if (!UTF8_IS_START(u))
+            return 0;
 
-    len = UTF8SKIP(s);
+        len = UTF8SKIP(s);
 
-    if (len < 2 || !UTF8_IS_CONTINUATION(s[1]))
-	return 0;
+        if (len < 2 || !UTF8_IS_CONTINUATION(s[1]))
+            return 0;
 
-    slen = len - 1;
-    s++;
-    u &= UTF_START_MASK(len);
-    uv  = u;
-    ouv = uv;
-    while (slen--) {
-	if (!UTF8_IS_CONTINUATION(*s))
-	    return 0;
-	uv = UTF8_ACCUMULATE(uv, *s);
-	if (uv < ouv) 
-	    return 0;
-	ouv = uv;
-	s++;
-    }
+        slen = len - 1;
+        s++;
+        u &= UTF_START_MASK(len);
+        uv  = u;
+        ouv = uv;
+        while (slen--) {
+            if (!UTF8_IS_CONTINUATION(*s))
+                return 0;
+            uv = UTF8_ACCUMULATE(uv, *s);
+            if (uv < ouv) 
+                return 0;
+            ouv = uv;
+            s++;
+        }
 
-    if ((STRLEN)UNISKIP(uv) < len)
-	return 0;
+        if ((STRLEN)UNISKIP(uv) < len)
+            return 0;
 
-    return len;
+        return len;
+    }
 }
 
 /*