<?php 
/** 
 * Smarty plugin 
 * @package Smarty 
 * @subpackage plugins 
 */ 
 
 
/** 
 * Smarty {math} function plugin 
 * 
 * Type:     function<br> 
 * Name:     math<br> 
 * Purpose:  handle math computations in template<br> 
 * @link http://smarty.php.net/manual/en/language.function.math.php {math} 
 *          (Smarty online manual) 
 * @author   Monte Ohrt <monte at ohrt dot com> 
 * @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; 
    } 
 
    // strip out backticks, not necessary for math 
    $equation = str_replace('`','',$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/", " \$params['$key'] ", $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)); 
        } 
    } 
} 
 
/* vim: set expandtab: */ 
 
?> 
 
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