php ZipArchive 解压乱码问题

1、解决php ZipArchive 解压乱码问题
/**
 * @param string $zipName 需要解压的文件路径加文件名
 * @param string $dir  解压后的文件夹路径
 * @return bool
 */
function extractZipToFile($zipName,$dir){
    $zip = new \ZipArchive;
    if ($zip->open($zipName) === TRUE) {
        if(!is_dir($dir)) mkdir($dir,0775,true);
        $docnum = $zip->numFiles;
        for($i = 0; $i < $docnum; $i++) {
            $statInfo = $zip->statIndex($i,\ZipArchive::FL_ENC_RAW);
            $filename = $this->transcoding($statInfo['name']);
            if($statInfo['crc'] == 0) {
                //新建目录
                if(!is_dir($dir.'/'.substr($filename, 0,-1))) mkdir($dir.'/'.substr($filename, 0,-1),0775,true);
            } else {
                //拷贝文件
                copy('zip://'.$zipName.'#'.$zip->getNameIndex($i), $dir.'/'.$filename);
            }
        }
        $zip->close();
        return true;
    }else{
        return false;
    }
}

function transcoding($fileName){
    $encoding = mb_detect_encoding($fileName,['UTF-8','GBK','BIG5','CP936']);
    if (DIRECTORY_SEPARATOR == '/'){    //linux
        $filename = iconv($encoding,'UTF-8',$fileName);
    }else{  //win
        $filename = iconv($encoding,'GBK',$fileName);
    }
    return $filename;
}