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<?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;
 }
 
 // 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 {
 $template->assign($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));
 }
 }
 }
 
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