- fix rc_utf8_clean() on Windows (#1486232)

CHANGELOG

@@ -3,7 +3,7 @@ CHANGELOG RoundCube Webmail
 
 - Added server-side e-mail address validation with 'email_dns_check' option (#1485857)
 - Fix login page loading into an iframe when session expires (#1485952)
-- added option 'force_https_port' in 'force_https' plugin (#1486091)
+- Allow setting port number in 'force_https' option (#1486091)
 - Option 'force_https' replaced by 'force_https' plugin
 - Fix IE issue with non-UTF-8 characters in AJAX response (#1486159)
 - Partially fixed "empty body" issue by showing raw body of malformed message (#1486166)

program/include/rcube_shared.inc

@@ -599,12 +599,15 @@ function rc_utf8_clean($input)
     return $input;
   }
   
-  if (!is_string($input))
+  if (!is_string($input) || $input == '')
     return $input;
   
-  // iconv is 10x faster
-  if (function_exists('iconv'))
-    return iconv('UTF8', 'UTF8//IGNORE', $input);
+  // iconv/mbstring are much faster (especially with long strings)
+  if (function_exists('mb_convert_encoding') && ($res = mb_convert_encoding($input, 'UTF8', 'UTF8')))
+    return $res;
+
+  if (function_exists('iconv') && ($res = iconv('UTF8', 'UTF8//IGNORE', $input)))
+    return $res;
 
   $regexp = '/^('.
 //    '[\x00-\x7F]'.                                  // UTF8-1