<?php  
/* 
Zip file creation class 
makes zip files on the fly... 

use the functions add_dir() and add_file() to build the zip file; 
see example code below 

by Eric Mueller 
http://www.themepark.com 

v1.1 9-20-01 
  - added comments to example 

v1.0 2-5-01 

initial version with: 
  - class appearance 
  - add_file() and file() methods 
  - gzcompress() output hacking 
by Denis O.Philippov, webmaster@atlant.ru, http://www.atlant.ru 

*/  

// official ZIP file format: http://www.pkware.com/appnote.txt 

class zipfile   
{   

    var $datasec = array(); // array to store compressed data 
    var $ctrl_dir = array(); // central directory    
    var $eof_ctrl_dir = "\x50\x4b\x05\x06\x00\x00\x00\x00"; //end of Central directory record 
    var $old_offset = 0;  

    function add_dir($name)    

    // adds "directory" to archive - do this before putting any files in directory! 
    // $name - name of directory... like this: "path/" 
    // ...then you can add files using add_file with names like "path/file.txt" 
    {   
        $name = str_replace("\\", "/", $name);   

        $fr = "\x50\x4b\x03\x04";  
        $fr .= "\x0a\x00";    // ver needed to extract 
        $fr .= "\x00\x00";    // gen purpose bit flag 
        $fr .= "\x00\x00";    // compression method 
        $fr .= "\x00\x00\x00\x00"; // last mod time and date 

        $fr .= pack("V",0); // crc32 
        $fr .= pack("V",0); //compressed filesize 
        $fr .= pack("V",0); //uncompressed filesize 
        $fr .= pack("v", strlen($name) ); //length of pathname 
        $fr .= pack("v", 0 ); //extra field length 
        $fr .= $name;   
        // end of "local file header" segment 

        // no "file data" segment for path 

        // "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));  

        // ext. file attributes mirrors MS-DOS directory attr byte, detailed 
        // at http://support.microsoft.com/support/kb/articles/Q125/0/19.asp 

        // now add to central record 
        $cdrec = "\x50\x4b\x01\x02";  
        $cdrec .="\x00\x00";    // version made by 
        $cdrec .="\x0a\x00";    // version needed to extract 
        $cdrec .="\x00\x00";    // gen purpose bit flag 
        $cdrec .="\x00\x00";    // compression method 
        $cdrec .="\x00\x00\x00\x00"; // last mod time & date 
        $cdrec .= pack("V",0); // crc32 
        $cdrec .= pack("V",0); //compressed filesize 
        $cdrec .= pack("V",0); //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 
        $ext = "\x00\x00\x10\x00";  
        $ext = "\xff\xff\xff\xff";   
        $cdrec .= pack("V", 16 ); //external file attributes  - 'directory' 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 array 
        $this -> ctrl_dir[] = $cdrec;   

          
    }  


    function add_file($data, $name)    

    // adds "file" to archive    
    // $data - file contents 
    // $name - name of file in archive. Add path if your want 

    {   
        $name = str_replace("\\", "/", $name);   
        //$name = str_replace("\\", "\\\\", $name); 

        $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 .= "\x00\x00\x00\x00"; // last mod time and date 

        $unc_len = strlen($data);   
        $crc = crc32($data);   
        $zdata = gzcompress($data);   
        $zdata = substr( substr($zdata, 0, strlen($zdata) - 4), 2); // fix crc bug 
        $c_len = strlen($zdata);   
        $fr .= pack("V",$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;   
        // end of "local file header" segment 
          
        // "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 .="\x00\x00\x00\x00"; // 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", $this -> old_offset ); //relative offset of local header 
//        echo "old offset is ".$this->old_offset.", new offset is $new_offset<br>"; 
        $this -> old_offset = $new_offset;  

        $cdrec .= $name;   
        // optional extra field, file comment goes here 
        // save to central directory 
        $this -> ctrl_dir[] = $cdrec;   
    }  

    function file() { // dump out 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 
    }  
}   

?>