<?php

/**

 * Smarty plugin

 * This plugin is only for Smarty2 BC

 *

 * @package    Smarty

 * @subpackage PluginsFunction

 */

/**

 * Smarty {math} function plugin

 * Type:     function<br>

 * Name:     math<br>

 * Purpose:  handle math computations in template

 *

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

 *           (Smarty online manual)

 * @author   Monte Ohrt <monte at ohrt dot com>

 *

 * @param array $params parameters

 * @param Smarty_Internal_Template $template template object

 *

 * @return string|null

 */

function smarty_function_math($params, $template) {

    static $_allowed_funcs = array(

        'int' => true, 'abs' => true, 'ceil' => true, 'cos' => true, 'exp' => true, 'floor' => true,

        'log' => true, 'log10' => true, 'max' => true, 'min' => true, 'pi' => true, 'pow' => true,

        'rand' => true, 'round' => true, 'sin' => true, 'sqrt' => true, 'srand' => true, 'tan' => true

    );

    // be sure equation parameter is present

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

        trigger_error("math: missing equation parameter", E_USER_WARNING);

        return;

    }

    $equation = $params['equation'];

    // make sure parenthesis are balanced

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

        trigger_error("math: unbalanced parenthesis", E_USER_WARNING);

        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);

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

        if ($curr_var && !isset($params[$curr_var]) && !isset($_allowed_funcs[$curr_var])) {

            trigger_error("math: function call $curr_var not allowed", E_USER_WARNING);

            return;

        }

    }

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

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

            // make sure value is not empty

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

                trigger_error("math: parameter $key is empty", E_USER_WARNING);

                return;

            }

            if (!is_numeric($val)) {

                trigger_error("math: parameter $key: is not numeric", E_USER_WARNING);

                return;

            }

            $equation = preg_replace("/\b$key\b/", " \$params['$key'] ", $equation);

        }

    }

    $smarty_math_result = null;

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

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

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

            return $smarty_math_result;

        } else {

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

        }

    } else {

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

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

        } else {

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

        }

    }

}