php读取txt是乱码怎么办

 //$fname文件名称
 if ($fname = $_FILES['nickname']['tmp_name']) {
 
 //file_get_contents() 函数把整个文件读入一个字符串中。
 $contents = file_get_contents($fname);
 //获取文件的编码方式
 $encoding = mb_detect_encoding($contents, array('GB2312','GBK','UTF-16','UCS-2','UTF-8','BIG5','ASCII'));
 
 $fp=fopen($fname,"r");//以只读的方式打开文件
 $text = "";
 $num = 0;
 if(!(feof($fp))) {
 $num++;
 $str = trim(fgets($fp));
 if ($encoding != false) {
 //iconv ()将$encoding 转换成“UTF-8”
 $str = iconv($encoding, 'UTF-8', $str);
 if ($str != "" and $str != NULL) {
 $text = $str;
 }
 }
 else {
 $str = mb_convert_encoding ( $str, 'UTF-8','Unicode');
 if ($str != "" and $str != NULL) {
 $text = $str;
 }
 }
 }
 while(!(feof($fp))) {
 $str = '';
 $str = trim(fgets($fp));
 if ($encoding != false) {
 $str = iconv($encoding, 'UTF-8', $str);
 if ($str != "" and $str != NULL) {
 $text = $text.",".$str;
 }
 }
 else {
 $str = mb_convert_encoding ( $str, 'UTF-8','Unicode');
 if ($str != "" and $str != NULL) {
 $text = $text.",".$str;
 }
 }
 }
 }