/**

 * Smarty plugin

 * @package Smarty

 * @subpackage plugins

 */

/**

 * Smarty {math} function plugin

 *

 * Type:     function

 * Name:     math

 * Purpose:  handle math computations in template

 * @link http://smarty.php.net/manual/en/language.function.math.php {math}

 *          (Smarty online manual)

 * @param array

 * @param Smarty

 * @return string

 */

function smarty_function_math($params, &$smarty)

{

    // be sure equation parameter is present

    if (empty($params['equation'])) {

        $smarty->trigger_error("math: missing equation parameter");

        return;

    }

    $equation = $params['equation'];

    // make sure parenthesis are balanced

    if (substr_count($equation,"(") != substr_count($equation,")")) {

        $smarty->trigger_error("math: unbalanced parenthesis");

        return;

    }

    // match all vars in equation, make sure all are passed

    preg_match_all("!(?:0x[a-fA-F0-9]+)|([a-zA-Z][a-zA-Z0-9_]+)!",$equation, $match);

    $allowed_funcs = array('int','abs','ceil','cos','exp','floor','log','log10',

                           'max','min','pi','pow','rand','round','sin','sqrt','srand','tan');

    foreach($match[1] as $curr_var) {

        if ($curr_var && !in_array($curr_var, array_keys($params)) && !in_array($curr_var, $allowed_funcs)) {

            $smarty->trigger_error("math: function call $curr_var not allowed");

            return;

        }

    }

    foreach($params as $key => $val) {

        if ($key != "equation" && $key != "format" && $key != "assign") {

            // make sure value is not empty

            if (strlen($val)==0) {

                $smarty->trigger_error("math: parameter $key is empty");

                return;

            }

            if (!is_numeric($val)) {

                $smarty->trigger_error("math: parameter $key: is not numeric");

                return;

            }

            $equation = preg_replace("/\b$key\b/",$val, $equation);

        }

    }

    eval("\$smarty_math_result = ".$equation.";");

    if (empty($params['format'])) {

        if (empty($params['assign'])) {

            return $smarty_math_result;

        } else {

            $smarty->assign($params['assign'],$smarty_math_result);

        }

    } else {

        if (empty($params['assign'])){

            printf($params['format'],$smarty_math_result);

        } else {

            $smarty->assign($params['assign'],sprintf($params['format'],$smarty_math_result));

        }

    }

}

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?>