Динамическое создание zip-архивов

/**
* Class to dynamically create a zip file (archive)
*
* @author Rochak Chauhan
*/

class createZip {

  public $compressedData = [];
  public $centralDirectory = []; // central directory
  public $endOfCentralDirectory = "\x50\x4b\x05\x06\x00\x00\x00\x00"; //end of Central directory record
  public $oldOffset = 0;

  /**
   * Function to create the directory where the file(s) will be unzipped
   *
   * @param $directoryName string
   *
   */

  public function addDirectory($directoryName) {
    $directoryName = str_replace("\\", "/", $directoryName);

    $feedArrayRow = "\x50\x4b\x03\x04";
    $feedArrayRow .= "\x0a\x00";
    $feedArrayRow .= "\x00\x00";
    $feedArrayRow .= "\x00\x00";
    $feedArrayRow .= "\x00\x00\x00\x00";

    $feedArrayRow .= pack("V",0);
    $feedArrayRow .= pack("V",0);
    $feedArrayRow .= pack("V",0);
    $feedArrayRow .= pack("v", strlen($directoryName) );
    $feedArrayRow .= pack("v", 0 );
    $feedArrayRow .= $directoryName;

    $feedArrayRow .= pack("V",0);
    $feedArrayRow .= pack("V",0);
    $feedArrayRow .= pack("V",0);

    $this -> compressedData[] = $feedArrayRow;

    $newOffset = strlen(implode("", $this->compressedData));

    $addCentralRecord = "\x50\x4b\x01\x02";
    $addCentralRecord .="\x00\x00";
    $addCentralRecord .="\x0a\x00";
    $addCentralRecord .="\x00\x00";
    $addCentralRecord .="\x00\x00";
    $addCentralRecord .="\x00\x00\x00\x00";
    $addCentralRecord .= pack("V",0);
    $addCentralRecord .= pack("V",0);
    $addCentralRecord .= pack("V",0);
    $addCentralRecord .= pack("v", strlen($directoryName) );
    $addCentralRecord .= pack("v", 0 );
    $addCentralRecord .= pack("v", 0 );
    $addCentralRecord .= pack("v", 0 );
    $addCentralRecord .= pack("v", 0 );
    $ext = "\x00\x00\x10\x00";
    $ext = "\xff\xff\xff\xff";
    $addCentralRecord .= pack("V", 16 );

    $addCentralRecord .= pack("V", $this -> oldOffset );
    $this -> oldOffset = $newOffset;

    $addCentralRecord .= $directoryName;

    $this -> centralDirectory[] = $addCentralRecord;
  }

  /**
   * Function to add file(s) to the specified directory in the archive
   *
   * @param $directoryName string
   *
   */

  public function addFile($data, $directoryName)  {

    $directoryName = str_replace("\\", "/", $directoryName);

    $feedArrayRow = "\x50\x4b\x03\x04";
    $feedArrayRow .= "\x14\x00";
    $feedArrayRow .= "\x00\x00";
    $feedArrayRow .= "\x08\x00";
    $feedArrayRow .= "\x00\x00\x00\x00";

    $uncompressedLength = strlen($data);
    $compression = crc32($data);
    $gzCompressedData = gzcompress($data);
    $gzCompressedData = substr( substr($gzCompressedData, 0, strlen($gzCompressedData) - 4), 2);
    $compressedLength = strlen($gzCompressedData);
    $feedArrayRow .= pack("V",$compression);
    $feedArrayRow .= pack("V",$compressedLength);
    $feedArrayRow .= pack("V",$uncompressedLength);
    $feedArrayRow .= pack("v", strlen($directoryName) );
    $feedArrayRow .= pack("v", 0 );
    $feedArrayRow .= $directoryName;

    $feedArrayRow .= $gzCompressedData;

    $feedArrayRow .= pack("V",$compression);
    $feedArrayRow .= pack("V",$compressedLength);
    $feedArrayRow .= pack("V",$uncompressedLength);

    $this -> compressedData[] = $feedArrayRow;

    $newOffset = strlen(implode("", $this->compressedData));

    $addCentralRecord = "\x50\x4b\x01\x02";
    $addCentralRecord .="\x00\x00";
    $addCentralRecord .="\x14\x00";
    $addCentralRecord .="\x00\x00";
    $addCentralRecord .="\x08\x00";
    $addCentralRecord .="\x00\x00\x00\x00";
    $addCentralRecord .= pack("V",$compression);
    $addCentralRecord .= pack("V",$compressedLength);
    $addCentralRecord .= pack("V",$uncompressedLength);
    $addCentralRecord .= pack("v", strlen($directoryName) );
    $addCentralRecord .= pack("v", 0 );
    $addCentralRecord .= pack("v", 0 );
    $addCentralRecord .= pack("v", 0 );
    $addCentralRecord .= pack("v", 0 );
    $addCentralRecord .= pack("V", 32 );

    $addCentralRecord .= pack("V", $this -> oldOffset );
    $this -> oldOffset = $newOffset;

    $addCentralRecord .= $directoryName;

    $this -> centralDirectory[] = $addCentralRecord;
  }

  /**
   * Fucntion to return the zip file
   *
   * @return zipfile (archive)
   */

  public function getZippedfile() {

    $data = implode("", $this -> compressedData);
    $controlDirectory = implode("", $this -> centralDirectory);

    return
      $data.
      $controlDirectory.
      $this -> endOfCentralDirectory.
      pack("v", sizeof($this -> centralDirectory)).
      pack("v", sizeof($this -> centralDirectory)).
      pack("V", strlen($controlDirectory)).
      pack("V", strlen($data)).
      "\x00\x00";
  }

  /**
   *
   * Function to force the download of the archive as soon as it is created
   *
   * @param archiveName string - name of the created archive file
   */

  public function forceDownload($archiveName) {
    $headerInfo = '';

    if(ini_get('zlib.output_compression')) {
      ini_set('zlib.output_compression', 'Off');
    }

    // Security checks
    if( $archiveName == "" ) {
      echo "<html><title>Public Photo Directory - Download </title><body><BR><B>ERROR:</B> The download file was NOT SPECIFIED.</body></html>";
      exit;
    }
    elseif ( ! file_exists( $archiveName ) ) {
      echo "<html><title>Public Photo Directory - Download </title><body><BR><B>ERROR:</B> File not found.</body></html>";
      exit;
    }

    header("Pragma: public");
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: private",false);
    header("Content-Type: application/zip");
    header("Content-Disposition: attachment; filename=".basename($archiveName).";" );
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".filesize($archiveName));
    readfile("$archiveName");

   }

}