PHP에서 폴더를 트랜스코딩하는 방법

<?php
/**
* 把一个文件夹里的文件全部转码 只能转一次 否则全部变乱码
* @param string $filename
*/
function iconv_file($filename,$input_encoding=&#39;gbk&#39;,$output_encoding=&#39;utf-8&#39;)
{
if(file_exists($filename))
{
if(is_dir($filename))
{
foreach (glob("$filename/*") as $key=>$value)
{
iconv_file($value);
}
}
else
{
$contents_before = file_get_contents($filename);
/*$encoding = mb_detect_encoding($contents_before,array(&#39;CP936&#39;,&#39;ASCII&#39;,&#39;GBK&#39;,&#39;GB2312&#39;,&#39;UTF-8&#39;));
echo $encoding;
if($encoding==&#39;UTF-8&#39;) mb_detect_encoding函数不工作
{
return;
}*/
$contents_after = iconv($input_encoding,$output_encoding,$contents_before);
file_put_contents($filename, $contents_after);
}
}
else
{
echo &#39;参数错误&#39;;
return false;
}
}
iconv_file(&#39;./test&#39;);
?>