字符中间加*星号，支持中英文

// 字符中间加*星号，支持中英文  add 202109111538
function str_chuli($str,$start,$end=0,$dot="*",$charset="UTF-8",$maxdot=8){

    $len = mb_strlen($str,$charset);

    // 只有2个字符时
    if($len == 2){
        return mb_substr( $str, 0, 1, $charset ).$dot.mb_substr( $str, -1, 1, $charset );
    }

    if($start==0||$start>$len){
        $start = 1;

    }

    if($end!=0&&$end>$len){
        $end = $len-2;

    }

    $endStart = $len - $end;
    $top = mb_substr($str, 0,$start,$charset);
    $bottom = "";

    if($endStart>0){
        $bottom = mb_substr($str, $endStart,$end,$charset);

    }

    $len = $len - mb_strlen($top,$charset);
    $len = $len - mb_strlen($bottom,$charset);
    $newStr = $top;
    //  最大星号数
    $len = $len > $maxdot? $maxdot : $len;

    for($i=0;$i<$len;$i++){

        $newStr.=$dot;

    }

    $newStr.=$bottom;
    return $newStr;

}