Detailed explanation of steps for php ZIP compression class example

<?php

$zipfiles =array("/root/pooy/test1.txt","/root/pooy/test2.txt");

$z = new PHPZip();

//$randomstr = random(8);

$zipfile = TEMP."/photocome_".$groupid.".zip";

$z->Zip($zipfiles, $zipfile); //添加文件列表

<?php

#

# PHPZip v1.2 by Sext (sext@neud.net) 2002-11-18

#     (Changed: 2003-03-01)

#

# Makes zip archive

#

# Based on "Zip file creation class", uses zLib

#

#

class PHPZip

{

    function Zip($dir, $zipfilename)

    {

        if (@function_exists('gzcompress'))

        {   

            $curdir = getcwd();

            if (is_array($dir))

            {

                    $filelist = $dir;

            }

            else

            {

                $filelist = $this -> GetFileList($dir);

            }

            if ((!empty($dir))&&(!is_array($dir))&&(file_exists($dir))) chdir($dir);

            else chdir($curdir);

            if (count($filelist)>0)

            {

                foreach($filelist as $filename)

                {

                    if (is_file($filename))

                    {

                        $fd = fopen ($filename, "r");

                        $content = fread ($fd, filesize ($filename));

                        fclose ($fd);

                        if (is_array($dir)) $filename = basename($filename);

                        $this -> addFile($content, $filename);

                    }

                }

                $out = $this -> file();

                chdir($curdir);

                $fp = fopen($zipfilename, "w");

                fwrite($fp, $out, strlen($out));

                fclose($fp);

            }

            return 1;

        }

        else return 0;

    }

    function GetFileList($dir)

    {

        if (file_exists($dir))

        {

            $args = func_get_args();

            $pref = $args[1];

            $dh = opendir($dir);

            while($files = readdir($dh))

            {

                if (($files!=".")&&($files!=".."))

                {

                    if (is_dir($dir.$files))

                    {

                        $curdir = getcwd();

                        chdir($dir.$files);

                        $file = array_merge($file, $this -> GetFileList("", "$pref$files/"));

                        chdir($curdir);

                    }

                    else $file[]=$pref.$files;

                }

            }

            closedir($dh);

        }

        return $file;

    }

    var $datasec      = array();

    var $ctrl_dir     = array();

    var $eof_ctrl_dir = "\x50\x4b\x05\x06\x00\x00\x00\x00";

    var $old_offset   = 0;

    /**

     * Converts an Unix timestamp to a four byte DOS date and time format (date

     * in high two bytes, time in low two bytes allowing magnitude comparison).

     *

     * @param  integer  the current Unix timestamp

     *

     * @return integer  the current date in a four byte DOS format

     *

     * @access private

     */

    function unix2DosTime($unixtime = 0) {

        $timearray = ($unixtime == 0) ? getdate() : getdate($unixtime);

        if ($timearray[&#39;year&#39;] < 1980) {

            $timearray['year']    = 1980;

            $timearray['mon']     = 1;

            $timearray['mday']    = 1;

            $timearray['hours']   = 0;

            $timearray['minutes'] = 0;

            $timearray['seconds'] = 0;

        } // end if

        return (($timearray[&#39;year&#39;] - 1980) << 25) | ($timearray[&#39;mon&#39;] << 21) | ($timearray[&#39;mday&#39;] << 16) |

                ($timearray[&#39;hours&#39;] << 11) | ($timearray[&#39;minutes&#39;] << 5) | ($timearray[&#39;seconds&#39;] >> 1);

    } // end of the 'unix2DosTime()' method

    /**

     * Adds "file" to archive

     *

     * @param  string   file contents

     * @param  string   name of the file in the archive (may contains the path)

     * @param  integer  the current timestamp

     *

     * @access public

     */

    function addFile($data, $name, $time = 0)

    {

        $name     = str_replace('\\', '/', $name);

        $dtime    = dechex($this->unix2DosTime($time));

        $hexdtime = '\x' . $dtime[6] . $dtime[7]

                   <a href="http://wutransfer.com/western-union-locations-in-russia-taiynsha/">Western union point</a> .  &#39;\x&#39; . $dtime[4] . $dtime[5]

                  . '\x' . $dtime[2] . $dtime[3]

                  . '\x' . $dtime[0] . $dtime[1];

        eval('$hexdtime = "' . $hexdtime . '";');

        $fr   = "\x50\x4b\x03\x04";

        $fr   .= "\x14\x00";            // ver needed to extract

        $fr   .= "\x00\x00";            // gen purpose bit flag

        $fr   .= "\x08\x00";            // compression method

        $fr   .= $hexdtime;             // last mod time and date

        // "local file header" segment

        $unc_len = strlen($data);

        $crc     = crc32($data);

        $zdata   = gzcompress($data);

        $c_len   = strlen($zdata);

        $zdata   = substr(substr($zdata, 0, strlen($zdata) - 4), 2); // fix crc bug

        $fr      .= pack('V', $crc);             // crc32

        $fr      .= pack('V', $c_len);           // compressed filesize

        $fr      .= pack('V', $unc_len);         // uncompressed filesize

        $fr      .= pack('v', strlen($name));    // length of filename

        $fr      .= pack('v', 0);                // extra field length

        $fr      .= $name;

        // "file data" segment

        $fr .= $zdata;

        // "data descriptor" segment (optional but necessary if archive is not

        // served as file)

        $fr .= pack('V', $crc);                 // crc32

        $fr .= pack('V', $c_len);               // compressed filesize

        $fr .= pack('V', $unc_len);             // uncompressed filesize

        // add this entry to array

        $this -> datasec[] = $fr;

        $new_offset        = strlen(implode('', $this->datasec));

        // now add to central directory record

        $cdrec = "\x50\x4b\x01\x02";

        $cdrec .= "\x00\x00";                // version made by

        $cdrec .= "\x14\x00";                // version needed to extract

        $cdrec .= "\x00\x00";                // gen purpose bit flag

        $cdrec .= "\x08\x00";                // compression method

        $cdrec .= $hexdtime;                 // last mod time & date

        $cdrec .= pack('V', $crc);           // crc32

        $cdrec .= pack('V', $c_len);         // compressed filesize

        $cdrec .= pack('V', $unc_len);       // uncompressed filesize

        $cdrec .= pack('v', strlen($name) ); // length of filename

        $cdrec .= pack('v', 0 );             // extra field length

        $cdrec .= pack('v', 0 );             // file comment length

        $cdrec .= pack('v', 0 );             // disk number start

        $cdrec .= pack('v', 0 );             // internal file attributes

        $cdrec .= pack('V', 32 );            // external file attributes - 'archive' bit set

        $cdrec .= pack('V', $this -> old_offset ); // relative offset of local header

        $this -> old_offset = $new_offset;

        $cdrec .= $name;

        // optional extra field, file comment goes here

        // save to central directory

        $this -> ctrl_dir[] = $cdrec;

    } // end of the 'addFile()' method

    /**

     * Dumps out file

     *

     * @return  string  the zipped file

     *

     * @access public

     */

    function file()

    {

        $data    = implode('', $this -> datasec);

        $ctrldir = implode('', $this -> ctrl_dir);

        return

            $data .

            $ctrldir .

            $this -> eof_ctrl_dir .

            pack('v', sizeof($this -> ctrl_dir)) .  // total # of entries "on this disk"

            pack('v', sizeof($this -> ctrl_dir)) .  // total # of entries overall

            pack('V', strlen($ctrldir)) .           // size of central dir

            pack('V', strlen($data)) .              // offset to start of central dir

            "\x00\x00";                             // .zip file comment length

    } // end of the 'file()' method

} // end of the 'PHPZip' class

?>