>>53
$str = "ファイア@炎";
$str =~ /^((?:\x81[\x40-\x7e\x80-\x96\x98-\xfc]|
[\x82-\x9f\xe0-\xef][\x40-\x7e\x80-\xfc]|
[\x20-\x3f\x41-\x7e])*)/x;
$str = $1;
print $str;