/lib/rdfapi-php/api/sparql/FilterFunctions.php

<?PHP

/**

* List of functions used to evaluate the FILTER statements in

* SPARQL queries.

*

* @package sparql

* @author   Tobias Gauss <tobias.gauss@web.de>

* @version	 $Id$

*

*/



 





/**

* Evaluates the regex() function. Returns true if the regex is matched false if not.

*

* @param String  $string   the string which has to be evaluated

* @param String  $pattern  the regex pattern

* @param String  $flags    additional flags like "i"

* @return boolean

*/

function regex($string,$pattern,$flags = ''){

	$string = trim($string);

	$pattern = trim($pattern);

	if(strpos($string,"str_")===0){

		$string = substr($string,4);

		$pattern = substr($pattern,4);

		$flags = substr($flags,4);

	}else{

		return false;

	}

	if(preg_match('/'.$pattern.'/'.$flags,$string))

	return true;

	else

	return false;

}



/**

* Evaluates the dateTime() function.Tries to convert a date string into

* a unix timestamp.

*

* @param  String $string the date string

* @return integer        the corresponding unix timestamp

*/

function dateTime($string){

	$string = trim($string);

	if(strpos($string,"str_")===0)

	$string = substr($string,4);



	$time = strtotime($string);

	if($time == -1)

	return $string;

	else

	return $time;

}





/**

* Evaluates the langMatches() function. Return true if the lang tag matches false if not.

*

* @param String $lang_range the string.

* @param String $lang_tag the regex pattern

* @return boolean

*/

function langMatches($lang_range,$lang_tag){



	if($lang_range == null)

	return false;



	if(strpos($lang_range,"str_")===0)

	$lang_range = substr($lang_range,4);

	if(strpos($lang_tag,"str_")===0)

	$lang_tag = substr($lang_tag,4);



	if(strtolower($lang_range) == strtolower($lang_tag))

	return true;

	$tags =  preg_match_all("/[^\-\s].[^\-\s]*/",$lang_range,$hits);

	if($tags){

		if($lang_tag == '*')

		return true;

		foreach($hits[0] as $tag){

			if(strtolower($tag) == strtolower($lang_tag))

			return true;

		}

		return false;

	}else{

		return false;

	}

}



/**

* Evaluates the str() function. Returns the string representation of a 

* variable or RDF term.

*

* @param  String $string the string

* @return boolean

*/

function str($string){

	$str = preg_match("/\".[^\"]*\"|\'.[^\']*\'/",$string,$hits);

	if($str != 0){

		return "str_".$hits[0];

	}else{

		if(strpos($string,"str_")===0){

			return $string;

		}else{

			if(strpos($string,"uri_")===0)

				return "str_".substr($string,4);

			if(strpos($string,'<')==0)

				return "str_".substr($string,1,-1);

		}

	}

	return false;

}



/**

* Evaluates the lang() function. Returns lang tag of a Literal.

*

* @param  String $string the string.

* @return String the lang tag or false if there is no language tag.

*/

function lang($string){

	$str = preg_match("/\".[^\"]*\"@(.[^\s]*)|\'.[^\']*\'@(.[^\s]*)/",$string,$hits);

	if($str){

		if($hits[1] != null)

		return $hits[1];

		else

		return $hits[2];

	}else{

		return false;

	}

}







?>