974 …public static function mb_trim(string $string, ?string $characters = null, ?string $encoding = nul…  argument
976 …return self::mb_internal_trim('{^[%s]+|[%1$s]+$}Du', $string, $characters, $encoding, __FUNCTION__…
979 …public static function mb_ltrim(string $string, ?string $characters = null, ?string $encoding = nu…  argument
981         return self::mb_internal_trim('{^[%s]+}Du', $string, $characters, $encoding, __FUNCTION__);
984 …public static function mb_rtrim(string $string, ?string $characters = null, ?string $encoding = nu…  argument
986         return self::mb_internal_trim('{[%s]+$}D', $string, $characters, $encoding, __FUNCTION__);
989 …private static function mb_internal_trim(string $regex, string $string, ?string $characters, ?stri…  argument
997         if ('' === $characters) {
1006             if (null !== $characters && !preg_match('//u', $characters)) {
1007                 $characters = @iconv('UTF-8', 'UTF-8//IGNORE', $characters);
1012             if (null !== $characters) {
1013                 $characters = iconv($encoding, 'UTF-8//IGNORE', $characters);
1017         if (null === $characters) {
1018 …$characters = "\\0 \f\n\r\t\v\u{00A0}\u{1680}\u{2000}\u{2001}\u{2002}\u{2003}\u{2004}\u{2005}\u{20…
1020             $characters = preg_quote($characters);
1023         $string = preg_replace(sprintf($regex, $characters), '', $string);