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|
<?php
namespace Smarty\FunctionHandler;
use Smarty\Template;
/**
* Smarty {math} function plugin
* Type: function
* Name: math
* Purpose: handle math computations in template
*
* @author Monte Ohrt <monte at ohrt dot com>
*
* @param array $params parameters
* @param Template $template template object
*
* @return string|null
*/
class Math extends Base {
public function handle($params, Template $template) {
static $_allowed_funcs =
[
'int' => true,
'abs' => true,
'ceil' => true,
'acos' => true,
'acosh' => true,
'cos' => true,
'cosh' => true,
'deg2rad' => true,
'rad2deg' => true,
'exp' => true,
'floor' => true,
'log' => true,
'log10' => true,
'max' => true,
'min' => true,
'pi' => true,
'pow' => true,
'rand' => true,
'round' => true,
'asin' => true,
'asinh' => true,
'sin' => true,
'sinh' => true,
'sqrt' => true,
'srand' => true,
'atan' => true,
'atanh' => true,
'tan' => true,
'tanh' => true
];
// be sure equation parameter is present
if (empty($params['equation'])) {
trigger_error("math: missing equation parameter", E_USER_WARNING);
return;
}
$equation = $params['equation'];
// Remove whitespaces
$equation = preg_replace('/\s+/', '', $equation);
// Adapted from https://www.php.net/manual/en/function.eval.php#107377
$number = '-?(?:\d+(?:[,.]\d+)?|pi|π)'; // What is a number
$functionsOrVars = '((?:0x[a-fA-F0-9]+)|([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*))';
$operators = '[,+\/*\^%-]'; // Allowed math operators
$regexp = '/^((' . $number . '|' . $functionsOrVars . '|(' . $functionsOrVars . '\s*\((?1)*\)|\((?1)*\)))(?:' . $operators . '(?1))?)+$/';
if (!preg_match($regexp, $equation)) {
trigger_error("math: illegal characters", E_USER_WARNING);
return;
}
// make sure parenthesis are balanced
if (substr_count($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));
}
}
}
}
|
