/**
     * Tests if a string starts with a given string
     *
     * @param     string
     * @param     string
     * @return    bool
     */
    function startWith($string, $start)
    {
        return strpos($string, $start) === 0;
    }

    /**
     * Tests if a string ends with the given string
     *
     * @param     string
     * @param     string
     * @return    bool
     */
    function endWith($string, $end)
    {
        return strrpos($string, $end) === strlen($string) - strlen($end);
    }

function debug($object)
{
    echo '<div>';
 
    $calledFrom = debug_backtrace();
    echo '<strong>' . $calledFrom[0]['file'] . '</strong>';
    echo ' (line <strong>' . $calledFrom[0]['line'] . '</strong>)';
 
    echo('<pre>');
    if(is_array($object))
    {
        print_r($object);
    }
    elseif(is_a($object, 'DOMDocument'))
    {
        $object->formatOutput = true;
        $xml_string = $object->saveXML();
        echo htmlentities($xml_string);
    }
    elseif(is_a($object, 'DOMNodeList') || is_a($object, 'DOMElement'))
    {
        $dom = new DOMDocument();
        $debugElement = $dom->createElement('debug');
        $dom->appendChild($debugElement);
 
        if(is_a($object, 'DOMNodeList'))
        {
            foreach ($object as $node) 
            {
            	$node = $dom->importNode($node, true);
            	$debugElement->appendChild($node);
            }
        }
        elseif(is_a($object, 'DOMElement'))
        {
            $node = $dom->importNode($object, true);
            $debugElement->appendChild($node);
        }
 
        $dom->formatOutput = true;
        $xml_string = $dom->saveXML();
        echo htmlentities($xml_string);
    }
    elseif(is_object($object))
    {
        echo get_class($object);
    }
    else 
    {
        echo $object;
    }
    echo('</pre>');
 
    echo '</div>';
}

/**
* Converts a UNIX timestamp (as returned by time()) to a datetime string
* for use in SQL queries.
* @param int $date The date as a UNIX timestamp.
* @return string The date in datetime format.
*/
static function to_db_date($date)
{
    if (isset($date))
    {
        return date('Y-m-d H:i:s', $date);
    }
    else
    {
        return null;
    }
}

/**
* Converts a datetime value (as retrieved from the database) to a UNIX
* timestamp (as returned by time()).
* @param string $date The date as a UNIX timestamp.
* @return int The date as a UNIX timestamp.
*/
static function from_db_date($date)
{
	if (isset ($date))
	{
		return strtotime($date);
	}
	else
	{
		return null;
	}
}