refactor(encoding): Check if strings are valid for the specified enco…

…ding

Signed-off-by: Git'Fellow <[email protected]>

lib/private/Files/Storage/Wrapper/Encoding.php

@@ -37,7 +37,7 @@ public function __construct(array $parameters) {
 	 * Returns whether the given string is only made of ASCII characters
 	 */
 	private function isAscii(string $str): bool {
-		return !preg_match('/[\\x80-\\xff]+/', $str);
+		return mb_check_encoding($str, 'ASCII');
 	}
 
 	/**