批量转换文件格式php代码

/** * 文件重命名 * @param  $directoryThe dir of files * @param  $ext1  The original of filename extension * @param  $ext2  Need to convert the filename extension * @param  $verbose * @return $num   已转换文件的数量 */function changeext($directory, $ext1, $ext2, $verbose = false) {  $num = 0;  if($curdir = opendir($directory)) {   while(false !== ($file = readdir($curdir))) {     if($file != '.' && $file != '..') {       $srcfile = $directory . '/' . $file;       $string  = "$file";       $str    = strlen($ext1);       $str++;       $newfile = substr($string, 0, -$str);       $newfile = $newfile.'.'.$ext2;       $dstfile = $directory . '/' . $newfile;       if (eregi("\.$ext1",$file)) { # Look at only files with a pre-defined extension       $fileHand = fopen($srcfile, 'r');       fclose($fileHand);       rename($srcfile, $dstfile );       }   # Recursive traverse       if(is_dir($srcfile)) {         $num += changeext($srcfile, $ext1, $ext2, $verbose);       }     }   }   closedir($curdir);  }  return $num;}changeext('upload/news', 'png', 'jpg',  'false');