php计算整个目录大小的方法

/** * Calculate the full size of a directory * * @author   Jonas John * @version   0.2 * @param    string  $DirectoryPath  Directory path */function CalcDirectorySize($DirectoryPath) {  // I reccomend using a normalize_path function here  // to make sure $DirectoryPath contains an ending slash  // To display a good looking size you can use a readable_filesize  // function.  $Size = 0;  $Dir = opendir($DirectoryPath);  if (!$Dir)    return -1;  while (($File = readdir($Dir)) !== false) {    // Skip file pointers    if ($File[0] == '.') continue;     // Go recursive down, or add the file size    if (is_dir($DirectoryPath . $File))            $Size += CalcDirectorySize($DirectoryPath . $File . DIRECTORY_SEPARATOR);    else       $Size += filesize($DirectoryPath . $File);      }  closedir($Dir);  return $Size;}//使用范例：$SizeInBytes = CalcDirectorySize('data/');