/**
 * 压缩zip文件
 *
 * @param 
 * @author 编程之家 jb51.cc jb51.cc
 **/
function emZip($orig_fname,$content) {
 if (!class_exists('ZipArchive',FALSE)) {
  return false;
 }
 $zip = new ZipArchive();
 $tempzip = EMLOG_ROOT . '/content/cache/emtemp.zip';
 $res = $zip->open($tempzip,ZipArchive::CREATE);
 if ($res === TRUE) {
  $zip->addFromString($orig_fname,$content);
  $zip->close();
  $zip_content = file_get_contents($tempzip);
  unlink($tempzip);
  return $zip_content;
 } else {
  return false;
 }
}