chamilo-lms2/main/inc/lib/formvalidator/Rule/CompareFields.php

<?php
/* For licensing terms, see /license.txt */

/**
 * QuickForm rule to check a date
 */
class HTML_QuickForm_Compare_Fields extends HTML_QuickForm_Rule_Compare 
{
	/**
	 * Function to check an array of fields 	 
	 * @param   array of field names
     * @param   string operator ==, >=, etc
     * @param   string the value to compare
	 * @return boolean True if date is valid
	 */
	function validate($values, $operator_and_max_value) {
        if (is_array($values) && !empty($values) && !empty($operator_and_max_value)) {
           $final_value = 0;
           foreach ($values as $value) {
               $final_value += $value;
           }
           $params = explode('@', $operator_and_max_value);
           $operator    = $params[0];
           $max_value   = $params[1];                      
           return parent::validate(array($final_value, $max_value), $operator);
        }
        return false;        
	}
}