<?php

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

class createZip  {

    public $compressedData = array();
    public $centralDirectory = array(); // 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");

     }

}
?>
