<?php
/*
$Id$

  This code is part of LDAP Account Manager (http://www.sourceforge.net/projects/lam)
  
  This code is based on phpLDAPadmin.
  Copyright (C) 2004  David Smith and phpLDAPadmin developers
  
  The original code was modified to fit for LDAP Account Manager by Roland Gruber.
  Copyright (C) 2005 - 2006  Roland Gruber

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


*/

/**
 * Functions and classes for exporting LDAP entries to others formats (LDIF,DSML,..)
 * An example is provided at the bottom of this file if you want implement yours.
 *
 * @package tools
 * @author The phpLDAPadmin development team
 * @author Roland Gruber
 */ 

/** used to print status messages */
include_once('status.inc');

// registry for the exporters
$exporters = array();

$exporters[] = array(
	'output_type'=>'ldif',
	'desc' => 'LDIF',
	'extension' => 'ldif'
);
      
$exporters[] = array(
	'output_type'=>'dsml',
	'desc' => 'DSML V.1',
	'extension' => 'xml'
);

$exporters[] = array(
	'output_type'=>'vcard',
	'desc' => 'VCARD 2.1',
	'extension' => 'vcf'
);

$exporters[] = array(
	'output_type'=>'csv',
	'desc' => 'CSV',
	'extension' => 'csv'
);

/**
 * This class encapsulate informations about the ldap server 
 * from which the export is done.
 * The following info are provided within this class: 
 *
 * $base_dn:  if the source of the export is the ldap server, 
 *            it indicates the base dn of the search.
 * $query_filter: if the source of the export is the ldap server,
 *                 it indicates the query filter for the search.
 * $scope: if the source of the export is the ldap server,
 *         it indicates the scope of the search.
 *
 * @package tools
 */

class LdapExportInfo {

  var $base_dn;
  var $query_filter;
  var $scope;

  /**
   * Create a new LdapExportInfo object
   *
   * @param String $base_dn the base_dn for the search in a ldap server
   * @param String $query_filter the query filter for the search
   * @param String $scope the scope of the search in a ldap server
   */

  function LdapExportInfo($base_dn = NULL, $query_filter = NULL, $scope = NULL){
    $this->base_dn = $base_dn;
    $this->query_filter = $query_filter;
    $this->scope = $scope;
  }
}


/**
 * This class represents the base class of all exporters
 * It can be subclassed directly if your intend is to write
 * a source exporter(ie. it will act only as a decoree 
 * which will be wrapped by an another exporter.)
 * If you consider writting an exporter for filtering data 
 * or directly display entries, please consider subclass
 * the PlaExporter
 *
 * @see PlaExporter
 * @package tools
 */

class PlaAbstractExporter{

  /**
   * Return the number of entries
   * @return int the number of entries to be exported
   */
  function pla_num_entries(){}

  /**
   * Return true if there is some more entries to be processed
   * @return bool if there is some more entries to be processed
   */
  function pla_has_entry(){}

  /**
   * Return the entry as an array
   * @return array  an entry as an array
   */
  function pla_fetch_entry_array(){}

  /**
   * Return the entry as an Entry object
   * @return Entry an entry  as an Entry Object
   */
  function pla_fetch_entry_object(){}

  /**
   * Return a PlaLdapInfo Object
   * @return LdapInfo Object with info from the ldap serveur
   */
  function pla_get_ldap_info(){}

}// end PlaAbstractExporter


/**
 * PlaExporter acts a wrapper around another exporter.
 * In other words, it will act as a decorator for another decorator
 *
 * @package tools
 */
class PlaExporter extends PlaAbstractExporter{
  // the default CRLN 
  var $br="\n";
  // the wrapped $exporter
  var $exporter;

  /**
   * Constructor
   * @param source $source the decoree for this exporter
   */
  function PlaExporter( $source ){
    $this->exporter = $source;
  }
  
  /**
   * Return the number of entries
   * @return int the number of entries to be exported
   */
  function pla_num_entries(){
    return $this->exporter->pla_num_entries();
  }

  /**
   * Return true if there is some more entries to be processed
   * @return bool if there is some more entries to be processed
   */
  function pla_has_entry(){
    return $this->exporter->pla_has_entry();
  }

  /**
   * Return the entry as an array
   * @return array  an entry as an array
   */  
  function pla_fetch_entry_array(){
    return $this->exporter->pla_fetch_entry_array();
  }

  /**
   * Return the entry as an Entry object
   * @return Entry an entry  as an Entry Object
   */
  function pla_fetch_entry_object(){
      return $this->exporter->pla_fetch_entry_object();
  }

  /**
   * Return a PlaLdapInfo Object
   * @return LdapInfo Object with info from the ldap serveur
   */
  function pla_get_ldap_info(){
    return $this->exporter->pla_get_ldap_info();
  }

  /**
   * Helper method to check if the attribute value should be base 64 encoded.
   * @param String $str the string to check.
   * @return bool true if the string is safe ascii, false otherwise.
   */
  function is_safe_ascii( $str ){
    for( $i=0; $i<strlen($str); $i++ )
      if( ord( $str{$i} ) < 32 || ord( $str{$i} ) > 127 )
	return false;
    return true;
  }
    
  /**
   * Abstract method use to export data. 
   * Must be implemented in a sub-class if you write an exporter 
   * which export data.
   * Leave it empty if you write a sub-class which do only some filtering.
   */
  function export(){}
  
  /**
   * Set the carriage return /linefeed for the export
   * @param String $br the CRLF to be set
   */
  function setOutputFormat( $br ){
    $this->br = $br;
  }

}// end PlaExporter


/**
 * Export data from a ldap server
 * @extends PlaAbstractExporter
 * @package tools
 */

class PlaLdapExporter extends PlaAbstractExporter{
  var $entry_id;
  var $results;
  var $scope;
  var $entry_array;
  var $num_entries;
  var $ldap_info;
  var $queryFilter;
  var $hasNext;
  var $attributes;
  /**
   * Create a PlaLdapExporter object.
   * @param String $queryFilter the queryFilter for the export
   * @param String $base_dn the base_dn for the data to export
   * @param String $scope the scope for export
   */
  function PlaLdapExporter($queryFilter , $base_dn , $scope, $attributes){
    $this->scope = $scope;
    $this->base_dn = $base_dn;
    $this->queryFilter = $queryFilter;
    // infos for the server
    $this->ldap_info = new LdapExportInfo($base_dn,$queryFilter,$scope);
    // boolean to check if there is more entries
    $this->hasNext = 0;
    // boolean to check the state of the connection

    $this->attributes = $attributes;

    $this->ds = $_SESSION['ldap']->server;

    // get the data to be exported
    if( $this->scope == 'base' )
      $this->results = @ldap_read($this->ds, $this->base_dn, $this->queryFilter,$this->attributes);
    elseif( $this->scope == 'one' )
      $this->results = @ldap_list($this->ds, $this->base_dn, $this->queryFilter, $this->attributes);
    else // scope == 'sub'
      $this->results = @ldap_search($this->ds, $this->base_dn, $this->queryFilter, $this->attributes);
    
    // if no result, there is a something wrong
    if( ! $this->results ) 
      StatusMessage("ERROR", 'Encountered an error while performing search.', ldap_error( $this->ds ));
    
    // get the number of entries to be exported
    $this->num_entries = @ldap_count_entries( $this->ds,$this->results );

    if( $this->entry_id = @ldap_first_entry( $this->ds,$this->results ) ){
      $this->hasNext = 1;
    }
  }//end constructor

  /**
   * Return the entry as an array
   * @return array  an entry as an array
   */  
  function pla_fetch_entry_array(){
    return $this->entry_array;
  }

  /**
   * Return the entry as an Entry object
   * @return Entry an entry  as an Entry Object
   */
  function pla_fetch_entry_object(){
    // to do
  }
  
  /**
   * Return a PlaLdapInfo Object
   * @return LdapInfo Object with info from the ldap serveur
   */
  function pla_get_ldap_info(){
    return $this->ldap_info;
  }

  /**
   * Return the number of entries
   * @return int the number of entries to be exported
   */
  function pla_num_entries(){
    return $this->num_entries;
  }

  /**
   * Return true if there is some more entries to be processed
   * @return bool if there is some more entries to be processed
   */
  function pla_has_entry(){
    if( $this->hasNext ){
      unset( $this->entry_array );
      $dn = @ldap_get_dn( $this->ds,$this->entry_id );
      $this->entry_array['dn'] = $dn;
      
      //get the attributes of the entry
      $attrs = @ldap_get_attributes($this->ds,$this->entry_id);
      if( $attr = @ldap_first_attribute( $this->ds,$this->entry_id,$attrs ) ){
	
	//iterate over the attributes
	while( $attr ){
	  if( is_attr_binary( $this,$attr ) ){
	    $this->entry_array[$attr] = @ldap_get_values_len( $this->ds,$this->entry_id,$attr );
	  }
	  else{
	    $this->entry_array[$attr] = @ldap_get_values( $this->ds,$this->entry_id,$attr );
	  }
	  unset( $this->entry_array[$attr]['count'] );
	  $attr = @ldap_next_attribute( $this->ds,$this->entry_id,$attrs );
	}// end while attr
	
	if(!$this->entry_id = @ldap_next_entry( $this->ds,$this->entry_id ) ){
	  $this->hasNext = 0;
	}
      }// end if attr
      return true;
    }
    else{
      return false;
    }
  }
 
} // end PlaLdapExporter

/**
 * Export entries to ldif format
 * @extends PlaExporter
 * @package tools
 */
class PlaLdifExporter extends PlaExporter{

  // variable to keep the count of the entries
  var $counter = 0;

  // the maximum length of the ldif line
  var $MAX_LDIF_LINE_LENGTH = 76;

  /**
   * Create a PlaLdifExporter object
   * @param PlaAbstractExporter $exporter the source exporter
   */
  function PlaLdifExporter( $exporter ){
    $this->exporter = $exporter;
  }

  /**
   * Export entries to ldif format
   */
  function export(){
    $pla_ldap_info = $this->pla_get_ldap_info();
    $this->displayExportInfo($pla_ldap_info);

    //While there is an entry, fecth the entry as an array 
    while($this->pla_has_entry()){
      $entry = $this->pla_fetch_entry_array();
      $this->counter++;
      
      // display comment before each entry
      $title_string = "# " . _("Entry") . " " . $this->counter . ": " . $entry['dn'] ; 
      if( strlen( $title_string ) > $this->MAX_LDIF_LINE_LENGTH-3 )
	$title_string = substr( $title_string, 0, $this->MAX_LDIF_LINE_LENGTH-3 ) . "...";
      echo "$title_string$this->br";

      // display dn
      if( $this->is_safe_ascii( $entry['dn'] ))
	$this->multi_lines_display("dn: ". $entry['dn']);
      else
	$this->multi_lines_display("dn:: " . base64_encode( $entry['dn'] ));
      array_shift($entry);

      // display the attributes
      foreach( $entry as $key => $attr ){
	foreach( $attr as $value ){
	  if(  !$this->is_safe_ascii($value) || is_attr_binary($pla_ldap_info,$key ) ){
	    $this->multi_lines_display( $key.":: " . base64_encode( $value ) );
	  }
	  else{
	    $this->multi_lines_display( $key.": ".$value );
	  }
	}
      }// end foreach $entry

      echo $this->br;
      // flush every 5th entry (sppeds things up a bit)
      if( 0 == $this->counter % 5 )
	flush();
    }
  }
  
  // display info related to this export
  function displayExportInfo($pla_ldap_info){
    echo "version: 1$this->br$this->br";
    echo "# " . sprintf( _("LDIF Export for: %s"),  $pla_ldap_info->base_dn  ) . $this->br;
    echo "# " . _('Search scope') . ": " . $pla_ldap_info->scope . $this->br;
    echo "# " . _('Search filter') . ": " . $pla_ldap_info->query_filter . $this->br;
    echo "# " . _('Total entries') . ": " . $this->pla_num_entries() . $this->br; 
    echo $this->br;
  }

  /**
   * Helper method to wrap ldif lines
   * @param String $str the line to be wrapped if needed.
   */
  function multi_lines_display( $str ){
    
    $length_string = strlen($str);
    $max_length = $this->MAX_LDIF_LINE_LENGTH;
    
    while ($length_string > $max_length){
      echo substr($str,0,$max_length).$this->br." ";
      $str= substr($str,$max_length,$length_string);
      $length_string = strlen($str);
      
      // need to do minus one to align on the right
      // the first line with the possible following lines 
      // as these will have an extra space
      $max_length = $this->MAX_LDIF_LINE_LENGTH-1;
    }
    echo $str."".$this->br;
  }

}

/**
 * Export entries to DSML v.1
 * @extends PlaExporter
 * @package tools
 */

class PlaDsmlExporter extends PlaExporter{

  //not in use
  var $indent_step = 2;
  var $counter = 0;

  /**
   * Create a PlaDsmlExporter object
   * @param PlaAbstractExporter $exporter the decoree exporter
   */
  function PlaDsmlExporter( $exporter ){
    $this->exporter = $exporter;
  }

  /**
   * Export the entries to DSML
   */
   function export(){
     $pla_ldap_info = $this->pla_get_ldap_info();
     // not very elegant, but do the job for the moment as we have just 4 level
     $directory_entries_indent = "  ";
     $entry_indent= "    ";
     $attr_indent = "      ";
     $attr_value_indent = "        ";

     // print declaration
     echo "<?xml version=\"1.0\"?>$this->br";
     
     // print root element     
     echo "<dsml>$this->br";
     
     // print info related to this export
     echo "<!-- " . $this->br;
     echo "# " . sprintf( _("DSML Export for: %s"),  $pla_ldap_info->base_dn  ) . $this->br;
     echo "# " . _('Search scope') . ": " . $pla_ldap_info->scope . $this->br;
     echo "# " . _('Search filter') . ": " . $pla_ldap_info->query_filter . $this->br;
     echo "# " . _('Total entries') . ": " . $this->pla_num_entries() . $this->br; 
     echo "-->" . $this->br;


     echo $directory_entries_indent."<directory-entries>$this->br";
     //While there is an entry, fetch the entry as an array 
      while($this->pla_has_entry()){
	$entry = $this->pla_fetch_entry_array();
	$this->counter++;
	// display dn
	echo $entry_indent."<entry dn=\"". htmlspecialchars( $entry['dn'] ) ."\">".$this->br;
	array_shift($entry);
	
	// echo the objectclass attributes first
	if(isset($entry['objectClass'])){
	  echo $attr_indent."<objectClass>".$this->br;
	  foreach($entry['objectClass'] as $ocValue){
	    echo $attr_value_indent."<oc-value>$ocValue</oc-value>".$this->br;
	  }
	  echo $attr_indent."</objectClass>".$this->br;
	  unset($entry['objectClass']);
	}
	
	$binary_mode = 0;
	// display the attributes
	foreach($entry as $key=>$attr){
	  echo $attr_indent."<attr name=\"$key\">".$this->br;
	  
	  // if the attribute is binary, set the flag $binary_mode to true
	  $binary_mode = is_attr_binary($pla_ldap_info,$key)?1:0;
	  
	  foreach($attr as $value){
	    echo $attr_value_indent."<value>".($binary_mode?base64_encode( $value):  htmlspecialchars( $value ) )."</value>".$this->br;
	  }
	  echo $attr_indent."</attr>".$this->br;
	}// end foreach $entry
	echo $entry_indent."</entry>".$this->br;
	
	// flush every 5th entry (speeds things up a bit)
	if( 0 == $this->counter % 5 )
	  flush();
      }
      echo $directory_entries_indent."</directory-entries>$this->br";
      echo "</dsml>".$this->br;
   }
}


/**
 * @package tools
 */
class PlaVcardExporter extends PlaExporter{

  // mappping one to one attribute
  var $vcardMapping = array('cn' => 'FN',
			    'title' => 'TITLE',
			    'homePhone' => 'TEL;HOME',
			    'mobile' => 'TEL;CELL',
			    'mail' => 'EMAIL;Internet',
			    'labeledURI' =>'URL',
			    'o' => 'ORG',
			    'audio' => 'SOUND',
			    'facsmileTelephoneNumber' =>'TEL;WORK;HOME;VOICE;FAX',
			    'jpegPhoto' => 'PHOTO;ENCODING=BASE64',
			    'businessCategory' => 'ROLE',
			    'description' => 'NOTE'
			    );
  
  var $deliveryAddress  = array("postOfficeBox",
				"street",
				"l",
				"st",
				"postalCode",
				"c");

  function PlaVcardExporter($exporter){
    $this->exporter = $exporter;
  }

  /**
   * When doing an exporter, the method export need to be overriden.
   * A basic implementation is provided here. Customize to your need
   **/

  function export(){

    // With the method pla->get_ldap_info,
    // you have access to some values related
    // to you ldap server
    $ldap_info = $this->pla_get_ldap_info();
    $base_dn = $ldap_info->base_dn;
    $scope = $ldap_info->scope;
    $server_name = $ldap_info->name;
    $server_host = $ldap_info->host;

    while( $this->pla_has_entry() ){
      $entry = $this->pla_fetch_entry_array();

      //fetch the dn
      $dn = $entry['dn'];
      unset( $entry['dn'] );

      // check the attributes needed for the delivery address
      // field
      $addr = "ADR:";
      foreach( $this->deliveryAddress as $attr_name ){
	if( isset( $entry[$attr_name] ) ){
	  $addr .= $entry[$attr_name][0];
	  unset($entry[$attr_name]);
	}
	$addr .= ';';
      }
      echo "BEGIN:VCARD$this->br";

      // loop for the attributes
      foreach( $entry as $attr_name=>$attr_values ){

	// if an attribute of the ldap entry exist
	// in the mapping array for vcard
	if( isset( $this->vcardMapping[$attr_name] ) ){

	  // case of organisation. Need to append the
	  // possible ou attribute
	  if( 0 == strcasecmp( $attr_name , 'o' )){
	    echo $this->vcardMapping[$attr_name].":$attr_values[0]";
	    if( isset($entry['ou'] ) )
	      foreach( $entry['ou'] as $ou_value ){
		echo ";$ou_value";
	      }
	  }
	  // the attribute is binary. (to do : need to fold the line)
	  else if( 0 == strcasecmp( $attr_name,'audio') || 0 == strcasecmp( $attr_name,'jpegPhoto') ){
	    echo $this->vcardMapping[$attr_name].":$this->br";
	    echo " ".base64_encode( $attr_values[0]);
	  }
	  /*	  else if( $attr_name == "sn"){
	    echo $this->vcardMapping[$attr_name].":$attr_values[0]";
	  }
	  elseif( $attr_name == "homePostalAddress"){
          }*/
	  // else just print the value with the relevant attribute name
	  else{
	    echo $this->vcardMapping[$attr_name].":$attr_values[0]";
	  }
	  echo $this->br;
	}
      }
      // need to check
      echo "UID:$dn";
      echo $this->br;
      echo "VERSION:2.1";
      echo $this->br;
      echo $addr;
      echo $this->br;
      echo "END:VCARD";
      echo $this->br;
    }// end while
  }
}


/**
 * Export to cvs format
 *
 * @author Glen Ogilvie
 * @package tools
 */

class PlaCSVExporter extends PlaExporter{

  function PlaCSVExporter($exporter){
    $this->exporter = $exporter;
  }
  
  /**
   * When doing an exporter, the method export need to be overriden.
   * A basic implementation is provided here. Customize to your need
   **/
  
  var $separator = ",";
  var $qualifier = '"';
  var $multivalue_separator = " | ";
  var $escapeCode = '"';
  
  function export(){
    
    // With the method pla->get_ldap_info,
    // you have access to some values related
    // to you ldap server
    $ldap_info = $this->pla_get_ldap_info();
    $base_dn = $ldap_info->base_dn;
    $scope = $ldap_info->scope;
    $server_name = $ldap_info->name;
    $server_host = $ldap_info->host;
    
    $entries = array();
    $headers = array();
		
    // go thru and find all the attribute names first.  This is needed, because, otherwise we have
    // no idea as to which search attributes were actually populated with data
    while( $this->pla_has_entry() ) {
      $entry = $this->pla_fetch_entry_array();
      foreach (array_keys($entry) as $key) {
	if (!in_array($key, $headers)) 
	  array_push($headers,$key);
      }
      array_push($entries, $entry);
    }
    
    $num_headers = count($headers);
    
    // print out the headers
    for ($i = 0; $i < $num_headers; $i++) {
      echo $this->qualifier. $headers[$i].$this->qualifier;
      if ($i < $num_headers-1) 
	echo $this->separator;
    }
    
    array_shift($headers);
    $num_headers--;
    
    echo $this->br;
	
    // loop on every entry
    foreach ($entries as $entry) {
      
      //print the dn
      $dn = $entry['dn'];
      unset( $entry['dn'] );
      echo $this->qualifier. $this->LdapEscape($dn).$this->qualifier.$this->separator;
      
      // print the attributes
      for($j=0;$j<$num_headers;$j++){

	$attr_name = $headers[$j];

	echo $this->qualifier;
	if (key_exists($attr_name, $entry)) {
	  $binary_attribute = is_attr_binary( $ldap_info, $attr_name )?1:0;
	  
	  $attr_values = $entry[$attr_name];
	  
	  $num_attr_values = count( $attr_values );
	  for( $i=0 ; $i<$num_attr_values; $i++){
	    if($binary_attribute)
	      echo base64_encode($attr_values[$i]);
	    else
	      echo $this->LdapEscape($attr_values[$i]);
	    
	    if($i < $num_attr_values - 1)
	      echo $this->multivalue_separator;
	    
	  }
	}// end if key
	echo $this->qualifier;
	if( $j < $num_headers - 1 )
	  echo $this->separator;
      }
          echo $this->br;
    }
  }//end export
  
  // function to escape data, where the qualifier happens to also 
  // be in the data.
  function LdapEscape ($var) {
    return str_replace($this->qualifier, $this->escapeCode.$this->qualifier, $var);
  }
}


/**
 * @package tools
 */

class MyCustomExporter extends PlaExporter{

  function MyCutsomExporter($exporter){
    $this->exporter = $exporter;
  }

  /**
   * When doing an exporter, the method export need to be overriden.
   * A basic implementation is provided here. Customize to your need
   **/


  function export(){

    // With the method pla->get_ldap_info,
    // you have access to some values related
    // to you ldap server
    $ldap_info = $this->pla_get_ldap_info();
    $base_dn = $ldap_info->base_dn;
    $scope = $ldap_info->scope;
    $server_name = $ldap_info->name;
    $server_host = $ldap_info->host;


    // Just a simple loop. For each entry 
    // do your custom export
    // see PlaLdifExporter or PlaDsmlExporter as an example 
    while( $this->pla_has_entry() ){
      $entry = $this->pla_fetch_entry_array();
      
      //fetch the dn
      $dn = $entry['dn'];
      unset( $entry['dn'] );
	    
      // loop for the attributes
      foreach( $entry as $attr_name=>$attr_values ){
	foreach( $attr_values as $value ){
	  
	  // simple example
	  // echo "Attribute Name:".$attr_name;
	  //  echo " - value:".$value;
	  // echo $this->br;
	  }
      }
      
    }// end while
  }

}

/**
 * Gets the USER_AGENT string from the $_SERVER array, all in lower case in
 * an E_NOTICE safe manner.
 * @return String The user agent string as reported by the browser.
 */
function get_user_agent_string()
{
    if( isset( $_SERVER['HTTP_USER_AGENT'] ) )
        return strtolower( $_SERVER['HTTP_USER_AGENT'] );
    else
        return false;
}

/**
 * Determines whether the browser's operating system is UNIX (or something like UNIX).
 * @return boolean True if the brower's OS is UNIX, false otherwise.
 */
function is_browser_os_unix()
{
    $agent = get_user_agent_string();
    if( ! $agent )
        return false;
    $unix_agent_strs = array(
            'sunos',
            'sunos 4',
            'sunos 5',
            'i86',
            'irix',
            'irix 5',
            'irix 6',
            'irix6',
            'hp-ux',
            '09.',
            '10.',
            'aix',
            'aix 1',
            'aix 2',
            'aix 3',
            'aix 4',
            'inux',
            'sco',
            'unix_sv',
            'unix_system_v',
            'ncr',
            'reliant',
            'dec',
            'osf1',
            'dec_alpha' ,
            'alphaserver' ,
            'ultrix' ,
            'alphastation',
            'sinix',
            'freebsd',
            'bsd',
            'x11',
            'vax',
            'openvms'
                );
            foreach( $unix_agent_strs as $agent_str )
                if( strpos( $agent, $agent_str ) !== false )
                    return true;
            return false;
}

/**
 * Determines whether the browser's operating system is Windows.
 * @return boolean True if the brower's OS is Windows, false otherwise.
 */
function is_browser_os_windows()
{
    $agent = get_user_agent_string();
    if( ! $agent )
        return false;
    $win_agent_strs = array(
            'win',
            'win95',
            'windows 95',
            'win16',
            'windows 3.1',
            'windows 16-bit',
            'windows',
            'win31',
            'win16',
            'winme',
            'win2k',
            'winxp',
            'win98',
            'windows 98',
            'win9x',
            'winnt',
            'windows nt',
            'win32',
            'win32',
            '32bit'
            );
    foreach( $win_agent_strs as $agent_str )
        if( strpos( $agent, $agent_str ) !== false )
            return true;
    return false;
}

/**
 * Determines whether the browser's operating system is Macintosh.
 * @return boolean True if the brower's OS is mac, false otherwise.
 */
function is_browser_os_mac()
{
    $agent = get_user_agent_string();
    if( ! $agent )
        return false;
    $mac_agent_strs = array(
            'mac',
            '68000',
            'ppc',
            'powerpc'
            );
    foreach( $mac_agent_strs as $agent_str )
        if( strpos( $agent, $agent_str ) !== false )
            return true;
    return false;
}


?>