public function item_count(array $aArray, $sParam)
    {
        $aParams  = preg_replace('/[^0-9]/', '', explode(',', $sParam));
        $mFloor   = ArrayHelper::getFromArray(0, $aParams, 0);
        $mCeiling = ArrayHelper::getFromArray(1, $aParams, INF);

        if (substr($sParam, 0, 1) === '(' && substr($sParam, -1, 1) === ')') {
            $mFloor++;
            $mCeiling--;
        }

        if (($bAboveFloor = $mFloor <= count($aArray)) === false) {
            $this->set_message('item_count', lang('fv_count_floor'));
        }

        if (($bBeneathCeiling = $mCeiling >= count($aArray)) === false) {
            $this->set_message('item_count', lang('fv_count_ceiling'));
        }

        return $bAboveFloor && $bBeneathCeiling;
    }