PHP question - download directories

Well, got asked to do some other things yesterday, which meant more wasted time... Don't you just hate it when that happens... tsch!

Anyway, I half way got a solution; I got the files to compress, but they don't open because they are corrupted or not saved properly. Here is the code I added:

The class

<?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  
[url]http://www.themepark.com[/url]  

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, [email]webmaster@...], [url]http://www.atlant.ru[/url]  

*/    

// official ZIP file format: [url]http://www.pkware.com/appnote.txt[/url]  

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 [url]http://support.microsoft.com/support/kb/articles/Q125/0/19.asp[/url]  

        // 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  

    {     
        $data = str_replace("\x0a", "\x0d\x0a", $data); 
        $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  
    }    
}  
?>

My code:

$zipfile = new zipfile();     

// add the subdirectory ... important!  
$zipfile -> add_dir("files/");    

// add the binary data stored in the string 'filedata'  
$var = array();
$filedata = array();
$var[] = "added_text.rtf";
$filedata[] = implode("",file("files/added_text.rtf")); 
$var[] = "cms_design.doc"; 
$filedata[] = implode("",file("files/cms_design.doc"));
$var[] = "icon_forum_france.jpg"; 
$filedata[] = implode("",file("files/icon_forum_france.jpg"));

for($i=0;$i<count($var);$i++)
	$zipfile->add_file($filedata[$i], "files/".$var[$i]);

// the next three lines force an immediate download of the zip file:  
header("Content-type: application/octet-stream");     
header("Content-disposition: attachment; filename=test.gz");     
print $zipfile->file(); 

Is there something I'm doing wrong? The idea is to set up each file data and name in corresponding arrays and then send them to the zip class.