<?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                    $params   parameters 
 * @param Smarty 
 * 
 * @return string|null 
 */ 
function smarty_function_math($params, &$smarty) 
{ 
    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; 
    } 
 
    // disallow backticks 
    if (strpos($equation, '`') !== false) { 
        trigger_error("math: backtick character not allowed in equation", E_USER_WARNING); 
 
        return; 
    } 
 
    // also disallow dollar signs 
    if (strpos($equation, '$') !== false) { 
        trigger_error("math: dollar signs not allowed in equation", 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; 
            } 
        } 
    } 
 
    // match all vars in equation, make sure all are passed 
    preg_match_all('!(?:0x[a-fA-F0-9]+)|([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)!', $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, or missing parameter '{$curr_var}'", E_USER_WARNING); 
 
            return; 
        } 
    } 
 
    foreach ($params as $key => $val) { 
        if ($key != "equation" && $key != "format" && $key != "assign") { 
            $equation = preg_replace("/\b$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 { 
            $smarty->assign($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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