php 批量去除项目文件bom头

 <?php
 if (isset($_GET['dir'])) { //设置文件目录
     $basedir = $_GET['dir'];
 } else {
     $basedir = '.';
 }

 $auto = 1;
 checkdir($basedir);

 function checkdir($basedir)
 {
     if ($dh = opendir($basedir)) {
         while (($file = readdir($dh)) !== false) {
             if ($file != '.' && $file != '..') {
                 if (!is_dir($basedir . "/" . $file)) {
                     echo "filename: $basedir/$file " . checkBOM("$basedir/$file") . " <br>";
                 } else {
                     $dirname = $basedir . "/" . $file;
                     checkdir($dirname);
                 }
             }
         }
         closedir($dh);
     }
 }

 function checkBOM($filename)
 {
     global $auto;
     $contents = file_get_contents($filename);
     $charset[1] = substr($contents, 0, 1);
     $charset[2] = substr($contents, 1, 1);
     $charset[3] = substr($contents, 2, 1);
     if (ord($charset[1]) == 239 && ord($charset[2]) == 187 && ord($charset[3]) == 191) {
         if ($auto == 1) {
             $rest = substr($contents, 3);
             rewrite($filename, $rest);
             return ("<font color='red'>BOM found, automatically removed.</font>");
         } else {
             return ("<font color='red'>BOM found.</font>");
         }
     } else
         return ("BOM Not Found.");
 }

 function rewrite($filename, $data)
 {
     $filenum = fopen($filename, "w");
     flock($filenum, LOCK_EX);
     fwrite($filenum, $data);
     fclose($filenum);
 }

 ?>